7143999_1

12 December 2018

AIR DISCHARGE ASSESSMENT

Envirofert – Compost and Managed Landfill, 74 Geraghtys Road, Tuakau

2

AIR DISCHARGE ASSESSMENT Envirofert – Compost and Managed Landfill, 74 Geraghtys Road, Tuakau

Contents 1 Introduction ....................................................................................... 4

1.1 Composting ............................................................................... 4

1.2 Managed Fill .............................................................................. 6

2 Existing Environment ........................................................................ 8

2.1 Meteorology .............................................................................. 9

2.2 Topography ............................................................................. 12

3 Assessment Criteria ......................................................................... 13

4 Identification of Sensitive Receptors ............................................... 14

5 Discharges to Air ............................................................................. 15

5.1 Sitewide mitigation.................................................................. 15

5.2 Composting operation ............................................................. 16

5.2.1 Process description .......................................................... 16

5.2.2 Potential odour discharges ............................................... 21

5.2.3 Potential dust discharges ................................................. 30

5.3 Managed Fill operation ............................................................ 31

5.3.1 Process description .......................................................... 31

5.3.2 Potential odour discharges ............................................... 32

5.3.3 Potential dust discharges ................................................. 32

6 Assessment of Effects ..................................................................... 33

6.1 Good Practise Guides for composting ...................................... 34

6.2 Analysis of published separation/buffer distances .................... 34

6.3 Comparison of the proposed composting operation against other similar operations ...................................................................... 35

6.3.1 Southern Horticultural Products ....................................... 35

6.3.2 Lenz Enterprises, Inc. ....................................................... 35

6.3.3 Summary ......................................................................... 36

6.4 Differences between the historic operation and proposed operation – expected reduction in effects ............................................ 36

NZ Air is an air quality

consultancy specializing

in expert evidence, air

discharge consent

applications, odour

assessments, nuisance

dust assessments, air

quality monitoring and

air dispersion modelling.

3

6.4.1 Composting operation ............................................................................................................... 36

6.4.2 Historic landfill operation ............................................................................................................ 37

6.4.3 Proposed changes to the operation ............................................................................................. 37

6.5 FIDOL Assessment .............................................................................................................................. 37

6.5.1 Frequency .................................................................................................................................. 38

6.5.2 Intensity ..................................................................................................................................... 38

6.5.3 Duration ..................................................................................................................................... 39

6.5.4 Offensiveness ............................................................................................................................. 40

6.5.5 Location ..................................................................................................................................... 41

6.5.6 Summary ................................................................................................................................... 41

7 Potential for cumulative effects ................................................................................................................. 41

8 Historic Complaints Analysis ..................................................................................................................... 42

9 Consultation with Neighbours ................................................................................................................... 43

10 Consideration of Alternatives ................................................................................................................ 44

11 Proposed Consent Conditions ................................................................................................................ 44

12 Conclusion ............................................................................................................................................. 44

4

1 Introduction Envirofert Limited (Envirofert) requires a new air discharge consent for a compost and landfill operation at 74 Geraghtys Road, Tuakau. This application needs to be lodged before the 31st December 2018 to provide for a continuation of the current consents (AUTH102300.01.01 and AUTH104419.01.03) whilst processing of the application occurs. The site location and nearest neighbouring receptors is shown in Figure 1.

Envirofert have contracted NZ Air Limited (NZ Air) to undertake a qualitative assessment of potential odour and dust effects from air discharges associated with the compost and landfill operations. The results of this assessment will be used to support an air discharge consent application.

Pre-application consultation has occurred between Waikato Regional Council (WRC) and their technical review team (Jacobs), Envirofert, and NZ Air, to ensure that the level of assessment and proposed outcomes are agreed.

Envirofert’s proposed hours of operation for the compost and landfill operation are: 6.30am – 6.00pm Monday to Friday; 8.00am – 5.00pm Saturday

FIGURE 1 SITE LOCATION AND NEAREST RECEPTORS

Aerial Imagery sourced from Google Earth November 2018

1.1 Composting Envirofert currently operate a green waste and food scraps composting operation. The historic management of this operation has been poor, resulting in a large number of verified off-site odour complaints, and enforcement action by the WRC. Recently new management took over the Envirofert operation, and this has resulted in a significant reduction in off-site complaints and enforcement action.

5

The historic composting operation of the site involved poor leachate and water management. This resulted in a number of the composting windrows and storage piles becoming anaerobic and discharging offensive odours.

A new sloped water impermeable composting pad is being constructed, this will separate storm water from the pad site allowing composting leachate and only the storm water on the Compost Pad area to be diverted into dedicated sumps which will transfer the leachate via pumps to a leachate storage pond for application to land.

It is proposed that in the future Envirofert will have the capacity to have two additional uses for the leachate and stormwater produced on-site. Firstly, Envirofert are investigating the potential for developing a liquid nutrient product line which would involve suppling customers with compost leachate as a liquid fertiliser. In this instance it is anticipated the leachate would be transported off-site in tankers to end clients. Secondly, Envirofert are researching charcoal treatment options to treat the water to a standard that it can be discharged into a wetland area which is proposed to be established in a low lying western portion of the site.

The proposed composting pad layout and associated water drainage plan is illustrated in Figure 2.

FIGURE 2 NEW SITE LAYOUT AND WATER DRAINAGE

After extensive consultation with Peter Moon of O2 Composting (a large, industry leader of composting systems, based out of Washington, USA), Envirofert are proposing to implement a new method of composting on-site. Composting will be undertaken using Extended Aerated Static Piles (EASP), this process is described in further detail in Section 5.2. This method of composting enables a much better control of temperature and available oxygen in the composting process and vastly reduces the potential for anaerobic conditions developing within the composting windrows. This form of composting speeds up the composting process and reduces offensive odours associated with anaerobic conditions.

6

Raw product will be trucked onto site in covered trucks, which will enter the site via the River Road entrance. The trucks will then pass over the site weighbridge prior to raw product (green waste and food scraps) being dumped at the dedicated receivals area (annotated as ‘green waste drop zone’ on Figure 2). Some raw products will be shredded to generate the desired product consistency. Raw products will then be mixed together (sometimes bulking agents such as sawdust will be added) to achieve the desired carbon to nitrogen ration (C:N) within the aeration windrows. Material which is too large to be incorporated into the aeration windrows (overs, mostly consists of large sticks) will be stored in the location marked as ‘wood overs’ on Figure 2. The mixed raw products (green waste, food scraps and bulking agents) will then be incorporated into an aeration windrow (either Aeration 1 or Aeration 2, as annotated in Figure 2).

Once the compost has completed its aeration cycle (usually lasts between 30 – 42 days), the compost will be moved to a maturation pile (either Maturation 1 or Maturation 2 as annotated on Figure 2). At times, overs will be mixed into the maturation mix to achieve the desired porosity in the maturation piles. Maturation takes approximately 30 – 60 days.

Once mature compost has been produced, a final screening step will take place prior to being transported off-site as finished product, or being stored in the storage sheds (at either end of the composting pad, see Figure 2).

Mature compost will be trucked off-site in covered trucks, which will leave via the main haul road which exits onto River Road. All trucks will pass through the on-site truck wash prior to leaving the site, so as to limit tracking compost or raw materials onto the main haul road or off-site.

Operational limits

• The proposed annual processing rates will be approximately 60,000 tonnes per year • The proposed maximum volume of greenwaste or food scraps in the feedstock receivals area is

300 m3. • The proposed maximum volume of compost in the aeration piles is 13,500 m3. • The proposed maximum volume of compost in the maturation piles is 13,500 m3. • It is proposed that the new aeration and maturation windrows will be approximately 3m in

height. • Approximately 15,000 m3 of mature compost for sale may be kept on-site. All mature compost

will be kept within covered storage and remain on-site for transport to clients as and when required by client demand. The on-site storage of mature compost will usually not be longer than 360 days.

The above measurable volume limits will limit the scale of the operation to ensure that the site’s operational capacity is not exceeded.

1.2 Managed Fill There are two historic landfill cells on-site (one in the north eastern corner, and one along the western side – see Figure 3). Both of these cells have historically received material which did not meet the Ministry for Environment (MfE) Cleanfill criteria1 and therefore have leachates which contain levels of metals and sulfidic compounds above the environmental acceptance limits. Envirofert have developed a containment program which will limit discharges to air and the amount of leachate being generated by these historic cells. Additionally, all leachate generated will be collected and contained separately and only combined with the Compost Leachate at the time of irrigation via a proposed venturi dilution

1 Ministry for Environment (2002) “Guide to the Management of Cleanfills”.

7

process. Furthermore, as a backup measure, Envirofert are exploring the possibility of treating the leachate (prior to discharge to land) to further minimise any environmental effects.

Envirofert propose to continue to operate a Managed Fill on eastern land parcels of the site (as illustrated in Figure 3). The waste acceptance criteria for this Managed Fill are as follows:

- Cleanfill that meets the MfE Cleanfill criteria2.

In addition, the following Managed Fill wastes, as stipulated within Envirofert Consents3, are acceptable for disposal:

- Polyethylene planter bags filled with growing medium - Silica Based Weatherboard - Glass and associated plastic tops etc

FIGURE 3 HISTORIC FILL CELLS AND MANAGED FILL LAYOUT/PROCESS DIAGRAM

It is anticipated that the rate of filling will be approximately 950 t/week and 50,000 t/year.

For each new cell the existing topsoil will be removed and used to form the perimeter bunds. Each cell (there are three new cells proposed), will have a clay base liner. No more than 0.5 hectares of the Managed Fill will be open/actively filled at any one time to limit dust emissions. It is expected that the total height of the Managed Fill lifts will be 3 – 5m in height.

Progressive clay capping will occur as each cell progresses southwards. The final surface will be covered with topsoil and re-grassed.

2 Ministry for Environment (2002) “Guide to the Management of Cleanfills”. 3 Consent Numbers xxx and xxxx

Leachate Sump 1

Leachate Sump 2

8

2 Existing Environment The current composting and landfilling operation is situated on land zoned as Rural in the Waikato District Plan. There is a number of isolated rural dwellings in an arc to the north east of the site (see Figure 1). The land to the south and west of the site is predominantly rural farm land. There is a small portion of residential zoned land adjacent to the northern boundaries of the site. The Waikato river bounds the southern portion of the site.

The surrounding Waikato District Plan zoning is included in Figure 4.

There is a number of potential odour producing industries in the vicinity of the site, including the Riverland Poultry farm and the Tuakau Proteins rendering plant (marked on Figure 1).

FIGURE 4 SURROUNDING DISTRICT PLAN ZONING

Envirofert

9

The Envirofert composting and landfill operations have been occurring on the site for 20 years and form part of the existing environment. Envirofert propose to vastly improve the on-site management and processes that have historically occurred on-site so as to improve the air quality amenity values in the surrounding area.

The Ministry for Environment Good Practice Guide for Assessing and Managing Odour – 2016 (MfE GPG) describes the sensitivity of receiving environments to odour impacts (in Section 2.5). In this guide, rural environments are considered to have a low sensitivity to rural type odours but have a high sensitivity to non-rural odours. For the purposes of this assessment it has been assumed that residences surrounding the proposed composting and Managed Fill operation would have a high sensitivity to odours associated with anaerobic decomposition of organic materials (which can be described as sour, pungent, foul in character). However, it is considered that these residences would have a low sensitivity to odours associated with aerobic decomposition (which can be described as earthy, musty in character) from the proposed Envirofert operation. For this reason, Envirofert are proposing to use a proven composting method with a high level of mitigation to ensure that aerobic conditions are maintained on-site.

2.1 Meteorology Local meteorological conditions have a direct bearing on the potential for odour and dust nuisance effects to occur at neighbouring properties, and need to be considered for an air discharge/land use consent.

Meteorological data has been sourced from the on-site weather station. Data for 2016 – 2017 (inclusive). A windrose of this dataset is presented in Figure 5.

A windrose shows the frequency of occurrence of winds by direction and strength. The bars correspond to the 16 compass points – N, NNE, NE, etc. The bar pointing vertically upwards in the wind rose diagram represents winds blowing from the north (i.e. northerly winds), and so on. The length of the bar

Envirofert

10

represents the frequency of occurrence of winds from that direction, and the widths of the bar sections correspond to wind speed categories, the narrowest representing the lightest winds. Thus, it is possible to visualise how often winds of a certain direction and strength occur over a long period.

The frequency distributions of these wind speeds and directions is included numerically in Table 1.

FIGURE 5 ENVIROFERT WEATHER STATION WINDROSE 2016 - 2017

11

TABLE 1 ENVIROFERT 2016 - 2017 WIND FREQUENCY DISTRIBUTION PERCENTAGES

Wind Sector Wind Parameters as a % Wind Speed (m/s) 0.5-2.0 2.0-3.0 3.0-5.0 5.0-10.0 >=10 All

CALM 9.2% N 2.6% 0.8% 1.7% 2.7% 0.3% 9.2% NNE 3.7% 0.6% 1.3% 1.0% 0.2% 6.8% NE 5.9% 0.7% 1.6% 0.4% 0.0% 8.5% ENE 4.7% 0.7% 0.4% 0.0% 0.0% 5.8% E 5.3% 1.9% 1.8% 0.4% 0.0% 9.5% ESE 1.9% 1.5% 2.9% 1.9% 0.0% 8.3% SE 0.5% 0.2% 0.5% 0.6% 0.0% 1.9% SSE 0.6% 0.2% 1.2% 0.8% 0.0% 2.8% S 0.5% 0.2% 0.8% 1.4% 0.0% 2.9% SSW 0.4% 0.5% 0.9% 1.2% 0.0% 3.0% SW 0.8% 0.5% 0.9% 3.6% 1.6% 7.3% WSW 0.4% 0.1% 0.1% 0.0% 0.0% 0.7% W 0.9% 0.5% 1.1% 2.1% 2.0% 6.5% WNW 2.4% 0.8% 2.1% 2.2% 0.7% 8.2% NW 2.2% 0.7% 1.8% 0.8% 0.0% 5.5% NNW 1.9% 0.9% 1.2% 1.0% 0.0% 4.9% Totals 34.6% 10.8% 20.4% 20.2% 4.8% 90.7%

To enable better visualisation of these wind patterns the windrose has been overlaid on top of the site in Figure 6.

12

FIGURE 6 ENVIROFERT WINDROSE 2016 - 2017 OVERLAID ON THE SITE

The windrose shows that the dominant winds occur from the North to East-Southeast, which would blow potential odour/dust emissions from the proposed Composting and Managed Fill operation away from the nearest off-site receptors. The lower wind speeds (less than 2 m/s), which are often associated with adverse odour effects due to poor dispersion conditions, generally occur from the Northeast quarter. This is consistent with cold air drainage flows towards the Waikato river. These low windspeed conditions would carry any odour generated from the site towards uninhabited farmland. Stronger winds (above 10 m/s) mostly occur from the Southwest – West and blow towards the nearest off-site receptors.

2.2 Topography The surrounding land is relatively flat with mild undulations, and falls in elevation towards the Waikato river. Cold air drainage flows across the site are expected to flow southwards towards the Waikato river.

The local terrain is illustrated in Figure 7. The low hill ranges at distance from the site are not expected have a large influence on the wind patterns in the local environment surrounding the site.

13

FIGURE 7 TERRAIN SURROUNDING THE SITE

3 Assessment Criteria The relevant rules, objectives and policies in both the Waikato Regional and District plans have been discussed in the AEE prepared by Bakers Associates. However, as a summary, the proposed composting operation is considered a Discretionary activity under Rule 5.2.8 of the Waikato Regional Plan, as it involves the composting of food scraps, has historically been subject to enforcement action, is increasing in scale, and exceeds the permitted activity processing rates.

The main potential discharge to air from the proposed continued operation of the Envirofert composting plant and Managed Fill is nuisance odour and dust. The rules in the Waikato District Plan and the Waikato Regional Plan refer to the ‘offensive or objectionable’ threshold for nuisance beyond the boundary of the activity. Therefore, for the purposes of this assessment the assessment criteria is considered to be the ‘offensive or objectionable’ threshold.

The method for assessing ‘offensive or objectionable’ odour involves undertaking an assessment using the FIDOL (Frequency, Intensity, Duration, Offensiveness and Location) factors, which is a technique commonly used throughout New Zealand.

The FIDOL criteria for assessing offensive and objectionable nuisance odour can be described as follows:

I. the frequency of odour nuisance events;

Envirofert

14

II. the intensity of events, as indicated by the degree of strength, but taking account of character or quality;

III. the duration of each odour nuisance event; IV. the offensiveness of the discharge, having regard to the character of the odour; including reference

to the “hedonic tone”; and V. the location of the odour nuisance, having regard to the sensitivity of the receiving environment,

including taking into account the relevant zone(s) and provisions in the Operative District Plan.

The MfE GPG for odour contains a list of tools to assist in the FIDOL assessments and NZ Air has used a number of the relevant tools in this assessment.

Given the separation distances between potential dust producing activities and the nearest off-site receptors, it is considered that there is a low likelihood for off-site nuisance dust effects. However, for completeness NZ Air has included potential dust emissions in the FIDOL assessment.

4 Identification of Sensitive Receptors A desktop study was undertaken to identify discrete receptors deemed sensitive to changes in air quality as a result of discharges from the proposed Envirofert operation. The nearest potentially affected sensitive receptors are marked in Figure 1 (yellow markers) and are summarised in Table 2.

In the context of the assessment contained in this report, the term 'sensitive receptor' is defined as a location where a sensitive activity occurs. Sensitive activity means an activity undertaken at a place or in an area where a person or persons are present and have a reasonable expectation that their enjoyment of the amenity values of that place or area will not be materially impaired by the effects of a discharge of odour, dust or smoke; and may include places where people gather for recreation, education, worship, culture or similar purposes, or where they reside, including outdoor living areas.

15

TABLE 2 LOCATION OF NEAREST RECEPTORS

Receptor ID Receptor Type Approximate distance from the composting

operation (m)

Direction Relative to the

Site R1 Residential 1,000 North

R2 Residential 1,050 Northeast

R3 Residential 1,000 Northeast

R4 Residential 1,050 Northeast

R5 Residential 1,050 Northeast

R6 Residential 980 Northeast

R7 Residential 1,050 East

R8 Residential 950 East

R9 Residential 850 East

R11 Residential 1,450 Southeast

R12 Residential 1,500 South

R13 Residential 1,600 South

R14 Residential 1,550 Southwest

R15 Residential 2,650 Southwest

R16 Residential 2,700 West

The separation distances of the above receptors from the proposed continued operation of the Managed Fill and management of historical landfill cells is less, however discharges from these activities have a lower potential for off-site effects. This is discussed further below.

5 Discharges to Air NZ Air has identified all of the potential discharges to air associated with the proposed composting and Managed Fill operation. These are described below, along with the proposed mitigation to prevent or minimise discharges from each source/activity.

5.1 Sitewide mitigation The following sitewide mitigation measures are to be applied by site staff. These are in addition to the activity specific measured outlined Section 5.2 and 5.3.

- Regular boundary odour observations for informing odour management. These boundary odour observations are to be made in accordance with the procedures outlined in the site’s operational management plan (OMP attached as Appendix A) (in general accordance with the MfE GPG guidance). Note that boundary observations are to be made on the southern boundary. However, given the proximity of the composting operation to this boundary and the very large separation distances between the operation and receptors in this direction, detectable odours

16

are acceptable on this boundary, but the intensity is to be at or below a ‘3 (distinct)’ on the odour intensity scale.

- Activities with a higher potential for odour emission are only to occur during favourable meteorological conditions. Favourable meteorological conditions are winds which are not blowing from the southwest (winds blowing from 180 – 270 degrees azimuth). Poor dispersion conditions such as; inversion layers, low windspeeds, overcast conditions (where thermal convective cells are less likely), cool temperatures, etc, are also to be avoided.

- Automated weather station alerts (from the existing on-site weather station) are to be observable to all site staff during wind directions from the south western quadrant (winds blowing from 180 – 270 degrees azimuth). These will be visualised by a wind sock and flashing light central to the site, and text message/e-mail alerts sent to site management.

- The site is to be maintained in a relatively clean operational condition. Good housekeeping is to be implemented by all site staff, i.e. tracking of compost outside of the lime stabilised pad is to be limited where possible, at the completion of an aeration or maturation windrow the pad is to be scraped clean to prevent compost remaining in the same location for several batches, regular inspections and cleaning of the aeration systems is to occur, etc.

- All emission control equipment (biofilter, aeration fans, screen dust controls, watercart, pond aerator, monitoring equipment, etc) is to be regularly inspected and maintained to ensure effective/consistent performance.

- Main haul road is to have a sign posted speed limit – 20 km/hr. - Staff inductions are to include education and training on the OMP. In particular, appropriate staff

are to be trained on the process for making boundary odour observations (as the feedback from these observations is critical in progressing mitigation levels, as outlined below).

- All site staff to know their responsibilities under the OMP. Failure to follow the procedures in the OMP will result in disciplinary action for site staff.

5.2 Composting operation 5.2.1 Process description A brief description of the composting process is included in Section 1.1, a detailed description of the proposed site processes is included in the OMP. The below is a summary of this detailed process description.

5.2.1.1 Initial Compost Mix - Mass Balance Procedures Mass balance estimates are used for planning purposes, and are not intended to be prescriptive. Because conditions and material properties vary daily and seasonally, the site operator must develop a talent for making adjustments to the mix composition and ratio of bulking agents in order to prepare an initial mix that can be effectively and efficiently composted without adverse impact to surface water, ground water or air quality.

The annual average quantities of feedstock materials that will be received at Envirofert Compost are summarized in Table 3. The target parameters for the initial compost mix include:

• Target-bulk density of 380 – 560 kg/m3 • Initial moisture content of 60 to 65 percent • Carbon to nitrogen ratio between 25:1 and 35:1

The composition and nutrient character of the green waste and food scraps changes significantly on and daily and annual basis. At certain times of year or dependant on the client supply, it can be comprised primarily of wet, nitrogen rich lawn clippings and trimmings. At other times of year such as

17

summer months, the materials can become progressively drier and more carbonaceous. Furthermore, the quantity and quality of food scraps can be highly variable. This material generally has a higher nitrogen component and is usually mixed in a low ration to greenwaste (approximately a 50:1).

TABLE 3 MASS BALANCE AT AVERAGE RATE

5.2.1.2 Making Great Compost 5.2.1.2.1 MATERIAL FLOW PLAN A generic process material flow diagram is provided as Figure 8. Each operations step depicted in the flow diagram is discussed in the following sections.

Description Approximate annual supply (Tonnes per year)

Bulk Density (kg/m3)

Greenwaste 42,500 350 Food scraps 9,000 600 Wood waste 8,500 300 Total Est. Quantity of Shredded Initial Mix

60,000

450 (Wetted)

Output: Estimated 40% Volume Reduction with Composting Total Est. Quantity Output Product

36,000 650

Screened Product 28,000 750 Screen Overs 8,000 (often recycled in compost) 300

18

FIGURE 8 COMPOST FLOW DIAGRAM

5.2.1.2.2 MIXING BULKING AGENTS Bulking agents typically consist of woody materials that have sufficient size to provide structural support and maintain air spaces within the composting matrix. Bulking agents form a three-dimensional matrix of solid particles capable of self-support by particle-to-particle contacts. Grass clippings and food scraps and similar "wet" feed stocks can be viewed as being supported within the voids between the bulking agent particles.

The bulking agents to be used for this process include: shredded wood waste and compost screen overs (i.e. coarse fraction). In the case of shredded green waste, the available nutrients are a source of energy for the compost material and thereby provide a secondary benefit. The screen overs serve to inoculate the initial mix of compost materials with microorganisms and to provide structure and porosity in the pile. These materials will be processed to a ~50 mm average size using the shredder that is dedicated to the site.

5.2.1.2.3 RECEIVING FEEDSTOCKS Feedstocks will be of three general types. One type will be woody or low nitrogen feed stocks. Generally, these will be land clearing debris, orchard pruning’s or solid wood materials that have little potential for odour generation. This material will be ground and used as a carbon source and for

19

bulking. This material will be ground and moved as needed to prepare the appropriate mix for composting.

The second type of feedstock will be greenwaste (i.e. curb side green bin collections) that is high in nitrogen. In all cases the delivery will be to a tipping area identified at the site. Greenwaste will comprise the majority of materials received and processed by Envirofert.

A third type of feedstock will be food scraps, including commercial collections (restaurants, supermarkets, event centres) and Auckland City kerb-side collections. Delivery will take place on the receiving area but then moved by loader to the mix being prepared for compost feedstock. The runoff from the receiving slab will have leachate retention. If this method causes nuisance odours Envirofert will prioritize pre-processing to place them within and EASP within 24-hours. Food scraps have historically comprised a small percentage of materials received and processed at the site.

All feed stock material will be tipped on the dedicated receivals area (see Figure 2).

5.2.1.2.4 PRE-PROCESSING AND BATCH MIXING Size reduction of the greenwaste materials will be accomplished with a front-end loader and a shredder that is located central to the site (marked as ‘shredder pad’ on Figure 2). Incoming materials will be reduced to a ~50 mm minus size and blended with bulking materials (shredded wood waste and horticultural residuals) as needed to provide an initial mix that has a carbon to nitrogen ratio (C:N) of between 25:1 and 35:1 and a moisture content of 60 to 65 percent.

The initial mixing will be accomplished promptly to produce a homogeneous blend of materials (as the first step to mitigate potentially offensive odours). Mixing will be accomplished partially using the front-end loader then completed during the shredding process. To obtain the proper mix the front-end loader scoop volume will be used as the unit of measure the operator will simply count bucket loads of the various mix components. Mixing will be performed by dumping on the EASP pad the appropriate proportions and lifting and combining the feedstock.

Samples of the initial mix may be taken as necessary to be and tested by a certified laboratory. Suitable methods of sampling and testing are discussed in detail in the "Quality Assurance Plan" section of the OMP. Test results will:

1) confirm that desired mix parameters are attained; and 2) provide baseline data to compare with typical lab results for finished compost.

Seasonal/daily adjustments of the initial mix will be necessary. Records of the mix ratios will be retained on-site such as to provide guidance to other site staff and future operators.

5.2.1.2.5 BUILDING EXTENDED AERATED STATIC PILES Envirofert will utilizes the EASP method of composting feed stocks. The EASP method uses perforated pipes placed on-grade prior to construction of the compost pile. The air pipe is connected to electric blowers, which force air into the compost pile (positive aeration). Contiguous compost cells are constructed directly on the flank (side slope) of the previous cell thereby producing a flat-topped extended pile (see Figure 9).

20

FIGURE 9 EASP CROSS SECTIONAL DIAGRAM

As each cell is being constructed, a 300 mm layer (minimum thickness) of finished compost is placed over the top of the raw feed stocks. This cover layer serves four main purposes:

1) Acting as an insulating blanket to ensure that all of the materials reach desired temperatures for pathogen and weed seed destruction;

2) Serving as a biofilter to digest odour-causing compounds before being emitted to the open air; 3) Helping to maintain the desired moisture content within the pile; and 4) Control vectors from breeding or burrowing in the pile.

Each EASP cell will contain approximately 840 m3 of feedstock materials, and each completed pile/windrow will contain a total of 6,750 m3. During peak operating conditions, there will generally be one fully constructed EASP and one partially constructed EASP at any given point in time. The entire composting process will take place without moving the pile. This step will take 21 to 30 days and completion will be based on the temperature cycle and the need to create space for subsequent piles.

By maintaining an oxygen level of at least 8 to 10 percent within the pile, aerobic conditions will be met, thereby mitigating offensive odours.

The extended piles will be constructed on a lime stabilised slab that slopes to drain by gravity to a leachate collection drain. The 2 piles will each measure approximately 25 m wide by up to 90 m long. The initial height of the pile will be on the order of 3 m. Over time, shrinkage will occur as a result of material consolidation and decomposition, reducing overall pile height to 2.5 m by the end of the active phase of composting.

5.2.1.2.6 ACTIVE COMPOSTING The active phase of composting (the period during which most of the process heat and potentially offensive odours are generated) generally lasts between 21 and 30 days and will take place in EASP’s, as discussed previously.

During the active phase of composting the primary objective is to reach temperatures throughout the pile of at least 55°C for a minimum of 72 hours. This standard is referred as the minimum pasteurisation time in NZS4454-2005 Composts, Soil Conditioner and Mulches. These criteria will be used to produce a safe finished product, available to the public for unrestricted use.

21

5.2.1.2.7 MATURATION The subsequent maturation phase of composting (the period during which the product becomes stable and marketable) lasts an additional 30 to 60 days. The curing phase may be accomplished either in the original compost pile, with adjusted airflow, or in a separate stockpile. EnviroFert will undertake curing in a separate stockpile. Given that the finished product is screened, the screening process can take place either before or following product maturation. The product maturation area is shown on Figure 2.

5.2.1.2.8 SCREENING Following maturation, the product will be screened to produce as many as three products.

1) Fine screened product, 2) Medium screened product; and 3) Screen overs.

The size of the fine and medium products will depend upon the size of the mesh used. Screen overs may be used as they are, or reground for size reduction. Often the screen overs are used as plenum, or biofilter cover or simply fed back into the pile for further composting.

5.2.1.2.9 STORAGE As part of the maturation process, the finished compost product will typically be stored for some period of time (typically not exceeding 360 days).

Storage of product following maturation will take place off the lime stabilised pad and off the area of leachate collection. Before product can be stored off the pad it must be confirmed that the metals concentration, pathogen destruction, pH, physical contaminants, sharps, and stability meet the levels specified in NZS4454-2005. Storage piles will be stored in weatherproof sheds (located at each end of the lime stabilised pad (as marked on Figure 2).

Storage piles must also be kept at a moisture content below 60% water. This can be accomplished by confirming with the squeeze test that the stored compost’s moisture is initially below 55%. The covered storage sheds will help maintain a dry stable final product.

Porosity in the storage piles will be achieved and maintained by keeping the height of the piles at or below 3 m. This will minimize consolidation and compaction. When the storage piles are constructed the operator will break up any existing dense areas from prior storage by handling with the loader (pouring and fluffing the material when building pile). The loader operator will avoid driving on the pile to prevent compaction.

In addition, performance standards specified in NZS4454-2005 must be achieved.

5.2.2 Potential odour discharges Nuisance odours associate with the proposed improved composting operation can be discharged from the following listed activities/sources. The proposed mitigation measures for each source are included under each potential source. To provide for a high level of odour control from the composting operation, Envirofert have proposed a staged mitigation approach. This provides for multiple factors of safety. Should Level 1 mitigation be insufficient to control odour discharges from the source/activity, then Level 2 mitigation will be applied, and so on until the odour discharges are controlled to a point that the odour emitted from the activity is not detectable at dwellings or sensitive locations beyond the boundary of the site.

The level of mitigation proposed is considered to be consistent with or to exceed good practise odour control for composting operations.

22

5.2.2.1 The transport of raw materials to and through the site The raw material which are provided to site consist of greenwaste, food scraps and bulking agents.

Greenwaste is generally sourced from ‘green bin’ residential collection, refuse transfer stations, horticultural waste products from the growing/processing of crops, and other minor sources.

Food scraps are generally sourced from commercial collections (restaurants, supermarkets, event centres) and Auckland City kerb-side collections.

Bulking agents such as wood pallets, saw dust and wood chip are transported to and stored on site. They are used to balance the C:N ratio in the aeration windrows/composting.

Mitigation

Level 1

All potentially odorous or dusty raw materials are to be delivered to site in covered trucks.

No material which has already begun to decompose anaerobically is to be transported to site.

The waste acceptance criteria is to be communicated to all customers/contractors. No waste other than what is specified in the resource consent, such as greenwaste or food scraps are to be delivered to site. Signage is to be placed at the entrance to the site clearly stating the composting materials that are acceptable.

Should prohibited waste be delivered to site, the load is to be immediately rejected and transported off-site. A record of the offending client/contractor is to be kept. Repeat offending will result in banning this client/contractor from providing waste to the site.

Level 2

Should fugitive odours still be escaping out of the truck covers and be detectable off-site, then the offending raw materials are to be transported to site in sealed containers. An investigation is to be undertaken by Envirofert as to the products that are generating odours during transport. Where possible Envirofert are to provide education and limits to customers/contractors as to the required condition of raw materials prior to transport. For example, food scraps are to be in a ‘fresh’ state, no more than 48 hours old, etc.

Level 3

No raw materials which have produced detectable odour at off-site locations during transport to or through the site are allowed to be transported to site. Customers/contractors whom have been supplying these materials are to be notified of the ban and should they continue to transport the offending products to site, be prohibited from transporting any material to site.

5.2.2.2 Raw product dumping and storage Once the raw products are received on-site. All greenwaste or food scraps will be dumped in the dedicated receivals area (marked on Figure 2). Any bulking agent received on site will be dumped in the sawdust/overs pile (marked on Figure 2).

Mitigation

Level 1

Site staff are to inspect each load of waste that is delivered to site. Should a waste product which is not included in the waste acceptance criteria (i.e. not food scraps or greenwaste) be delivered to site, then

23

this is to be prevented from dumping or reloaded on the truck immediately. The load is to be sent away from site, the incident is to be recorded, and site management are to be informed of the incident.

Should a particularly odorous load be delivered to site, this material is to be processed immediately and incorporated into an aeration windrow as soon as possible.

Food scraps are to be incorporated into an aeration windrow as soon as possible. Food scraps are not to be stored for more than 24 hours before being incorporated into a EASP windrow.

Greenwaste can be stored for up to 48 hours as long as it is sufficiently aerated as to prevent anaerobic decomposition from occurring.

Storage bins are to be regularly scrapped clean to ensure that there is no residual material left in the receivals areas for longer than the above holding times.

Where required receivals area is to be washed down to further assist in preventing foul odours. Wash water is to be directed into the leachate drains.

Level 2

Should the Level 1 controls not be sufficient to control odour to the point at which odour is detectable beyond the boundary of the site, then the offending odorous material is to be covered with mature compost, sawdust, or a plastic liner and not be processed until favourable wind conditions occur (i.e. winds not from the southwest).

No odorous waste is to be delivered during south westerly wind conditions.

Level 3

The offending waste is to be banned from being delivered to site.

5.2.2.3 Raw product shredding and mixing Once raw product has been delivered to site a portion of it is shredded. Overs (woody material too large for the aeration piles) is removed and the various waste streams, then the raw product is blended with bulking agents (saw dust, wood chip, etc) to achieve the desired C:N ratio (~30:1).

The active disturbance of these potentially odorous materials can result in the release of more intense odours. Therefore, the following mitigation is to be applied.

Mitigation

Level 1

As above in Section 5.2.2.2 the primary mitigation for this process is undertaking the works as soon as possible to ensure that decomposition is occurring in a controlled environment. Waste streams which result in unacceptable odour emissions are to be limited or banned.

Envirofert are to keep at least two operational shredders on-site at all times as a redundancy measure should one unit breakdown or require maintenance.

Shredders are to be maintained regularly to prevent build-up of waste on the machines themselves and ensure consistent operation.

Level 2

Should the shredding and mixing of the various waste streams result in odours detectable at the site boundary, then Envirofert are to investigate enclosing various aspects of the operation to reduce the

24

wind flow across the product lines and hence odour emissions. Enclosure options include; covered conveyors, shrouding or enclosing the shredder, undertaking the activities indoors, etc.

Undertake the processing of more odorous waste streams under more favourable wind conditions, i.e. winds not from the southwest.

Level 3

Cease the shredding, screening and mixing of the offending odorous waste streams. Truck any remaining odorous waste off-site to landfill.

5.2.2.4 Formation and operation of aeration windrows In the process description included in Section 5.2.1 and the OMP, there is a very prescriptive methodology for ensuring that the EASP windrows are constructed, monitored and maintained within strict parameters which will facilitate and maintain aerobic decomposition of the feedstock. The aerobic decomposition of the feedstock will result in musty, earthy odours in low intensities which are unlikely to result in nuisance odour effects.

Should this procedure not be followed in its entirety, then the potential for anaerobic decomposition is increased. Anaerobic decomposition of the feedstock will produce rotten, sour, pungent like odours which are likely to cause offensive or objectionable effects if detected off-site.

Much of the mitigation is discussed in Section 5.2.1 and the OMP, however below is a summary of the mitigation measures which are proposed to reduce the potential odour emissions.

Mitigation

Level 1

Ensure that the aeration windrows are situated on a sloped, free draining, elevated, impervious pad, so as to prevent leachate or stormwater accumulating in the base of the windrow. Undertake regular inspections for ponding of water at the base of the pile.

Ensure that the base of the aeration windrow is constructed in accordance with the OMP, such that even airflow from the EASP system can be directed through the compost pile and no pockets of anaerobic decomposition are occurring. Undertake regular visual inspections of steam emissions to ensure an even distribution of steam is occurring across the windrow.

Aeration windrows are to not be higher than 3m.

The C:N ratio is to be between 25 – 35. The mix of food scraps, greenwaste and bulking agents is to be recorded and as prescribed in the OMP.

Ensure that the porosity and bulk density of the aeration windrow is between 400 to 600 kg/m3 as stipulated in the OMP to enable even airflows and maintain aerobic conditions.

The compost is to have a moisture content of 60 – 65%. Monitor this via the ‘squeeze test’ and bucket weighing tests as stipulated in the OMP. Where the moisture content is too low (below 45%, apply water (or leachate), where it is too high (above 75%), mix in further dry material. Envirofert are to have access to sufficient water resource to maintain the applicable moisture content.

A water balance study is to be completed prior to composting operations commence (this is documented in the OMP). This water balance study is to be used to determine if local rainfall conditions will result in excess moisture content in the outdoor EASP’s during certain months of the year. If this study identifies risks that these conditions may occur, then either EASP composting is not to occur during these months or only covered EASP composting is to occur during these months.

25

Undertake regular temperature, pH, bulk density, and oxygen content monitoring such that these parameters do not exceed the recommended limits in the OMP for each stage of the composting process. These measurements are to be recorded on the site field sheets/logs such as to assess any changes in composition/composting conditions which may be trending outside the prescribed limits. Where these parameters exceed those stipulated in the OMP, undertake corrective actions (such as mixing, watering, adjusting fan operation, etc) to balance the pile conditions back to within the prescribed limits.

A 300mm layer of mature compost is to be placed over the formed aeration pile to provide a biofilter layer to reduce odour emissions from the EASP.

Ensure that the operation of the fans is undertaken in accordance with the procedures stipulated in the OMP. Amend the operation frequencies and durations to maintain the EASP temperatures within the desired ranges for the stage of composting.

Always have at least one standby fan available per EASP as a redundancy measure should a fan breakdown or require maintenance.

Undertake regular sniff tests to assess the character of the odour being released from the pile. Should anaerobic odours be detected coming from the EASP, investigate the source and rectify by restoring the EASP conditions as stipulated in the OMP and above.

Level 2

Should the Level 1 controls not be able to contain anaerobic odour emissions from the EASP, then the following backup controls are to be implemented.

Identify the source of the anaerobic odour, where the source is limited to a small portion of the EASP, then additional material (such as bulking agents, and mature compost) are to be mixed into this portion to promote aerobic conditions. Following on from this mixing, the restored product is to be reintegrated into the EASP. Then additional mature compost is to be placed over the surface of the EASP to reduce any residual anaerobic odour emissions. This mixing is to be undertaken during favourable wind conditions so as not to present a risk to off-site receptors.

If a large portion of the EASP is anaerobic or unfavourable wind conditions are occurring, or odour is detectible at the site boundary, then additional mature compost is to be added to the surface of the EASP as a biofilter layer to reduce/prevent odour release.

Level 3

Feed stock delivery to site is to cease.

All EASP composting is to cease until small scale trial or pilot studies can identify a viable method for maintaining aerobic composing using the available feedstock.

5.2.2.5 Transfer of compost from aeration windrows to maturation windrows and maturation phase composting

Once the aeration composting is complete, Envirofert propose to transfer the compost from Aeration 1 or Aeration 2 to Maturation 1 or Maturation 2 zones as identified in Figure 2. Where required additional material and/or overs will be added into the maturation mix to obtain the correct porosity/bulk density for maturation. It is proposed that this transfer process will be undertaken via a loader. Once the maturation windrow has been formed the compost will be matured/cured for a further 30 – 60 days.

26

Mitigation

Level 1

The transfer of compost from the EASP to the maturation pile will only occur to the adjacent pile (i.e. Aeration 1 to Maturation 1) so as to limit material handling and transport times.

Should at any time during the transfer of compost from one pile to another, anaerobic odours be detected, this portion of the pile will be immediately covered with mature compost till such time that it can be mixed into an EASP to restore aerobic conditions and eliminate anaerobic odour production.

During transfer, the EASP product will be inspected and tested (in accordance with the methodology stipulated in the OMP) to ensure that the EASP process is complete and the product is ready for maturation. Should the EASP process not be complete, the material is to be re-incorporated into the EASP until such time that the material meets the criteria in the OMP.

The maturation windrows are to be situated on a sloped, free draining, elevated, impervious pad, so as to prevent leachate or stormwater accumulating in the base of the windrow. Undertake regular inspections for ponding of water at the base of the pile.

The maturation windrows are to be constructed in accordance with the procedures in the OMP, in particular the bulk density and moisture content is to be maintained such that any further decomposition of organic matter in the windrow occurs aerobically.

Maturation windrow temperatures, pH, oxygen content, moisture content, and bulk density are to be measured in accordance with the methodology and frequency stipulated within the OMP (similar to that prescribed in Section 5.2.2.4 above). These measurements are to be recorded on the site logs such as to assess any changes in composition/composting conditions which may be trending outside the prescribed limits.

Regular odour checks are to be undertaken and recorded on the site logs. Should anaerobic odour be observed as coming from a maturation windrow, an investigation into the cause of the odour emission is to be undertaken and corrective actions are to be implemented (such as mixing, watering, etc).

Level 2

Should offensive odour be detected at the site boundary during the regular odour surveys, as a result of compost transfer from the Aeration windrows to the Maturation windrows, then this activity is to be limited to favourable meteorological conditions (i.e. winds not from the southwest).

Should the Level 1 mitigation not maintain aerobic decomposition within the static maturation piles, the material is to be transferred to an active EASP until such that the compost returns to an aerobic state.

If a large portion of the maturation windrow is anaerobic or unfavourable wind conditions are occurring, or odour is detectible at the site boundary then additional mature compost is to be added to the surface of the EASP as a biofilter layer to reduce/prevent odour release.

Level 3

Feed stock delivery to site is to cease.

All EASP and maturation composting is to cease until small scale trial or pilot studies can identify a viable method for maintaining aerobic composing using the available feedstock.

27

5.2.2.6 Transfer of compost from maturation windrow to screening pad, screening, storage, and load out of mature compost

After maturation, mature compost will have a low odour generation potential as nearly all of the organic material will have decomposed to a relatively dry stable product with a low odour production potential. Mature compost will have an earthy/musty odour.

After the maturation process is complete, the compost will be transferred to the screening pad adjacent to the storage shed (see Figure 2). Here the product will be screened and sorted into the various product lines for sale. Overs will be removed and stockpiled for use in earlier parts of the operation or shredded and incorporated into the EASP’s.

Final marketable products will be stored in the storage sheds (indicated on Figure 2) prior to load out. A loader will be used to load covered trucks for load out of final product to the end customers.

Mitigation

Level 1

If anaerobic odour is observed during transfer of mature compost to the screening plant or during screening, the activity will cease immediately and an investigation will occur as to the source of the odour.

Where anaerobic immature compost is present in the maturation pile, it will be mixed with bulking agents or overs to promote aerobic conditions. It will then be covered with mature compost to reduce the potential for odour emission.

Where unfavourable meteorological conditions are present, mature compost will be used to cover the offending compost, and mixing will not occur until favourable meteorological conditions return.

Storage of mature compost will occur within a covered shed, so as to prevent the product from getting wet and potentially releasing odour.

Final product will not normally be stored on-site for more than 360 days. This will minimise the potential intensity of any nuisance odour emissions from this source.

Level 2

As above should anaerobic compost be present in the maturation windrows, then Level 2 and potentially Level 3 mitigation as detailed in Section 5.2.2.5 is to be implemented.

Should the stored final product be releasing offensive odours the storage shed doors are to be closed to assist in containing odours until corrective actions can be undertaken to either stop the odour emission from the final product or re-incorporate the product into an EASP during favourable meteorological conditions.

Level 3

Feed stock delivery to site is to cease.

All EASP and maturation composting is to cease until small scale trial or pilot studies can identify a viable method for maintaining aerobic composing using the available feedstock.

If odorous stored final product cannot be successfully re-integrated into on-site aerobic composting, then it is to be trucked off-site to landfill in covered trucks.

28

5.2.2.7 Compost leachate collection and transfer to leachate storage pond The new pad design has been specifically designed to collect all leachate and stormwater and prevent accumulation of water within the active composting windrow and product storage areas. Leachate will be collected in leachate drain/sumps and pumped to the leachate storage pond.

This system has been designed to prevent the composting windrows from getting ‘wet feet’ which can result in anaerobic decomposition of the compost.

Furthermore, the system has been designed to stop ponding of water on-site which can form stagnant pools which become anaerobic due to the high organic/microbial content that is present in compost leachate.

Mitigation

Level 1

Regular inspection of the leachate drains, sumps and pumps is to occur to ensure that there is no blockages and the system is successfully transferring all leachate from the composting operation to the leachate pond.

Where ponding is occurring on the lime stabilised pad, portable surface pumps are to be used to pump water from the affected area to the nearest sump or the leachate pond. An investigation as to why ponding is occurring is to be instigated and where required the leachate drains are to be fixed or modified to prevent further ponding.

Sump pumps are to be regularly maintained to ensure consistent performance. Backup pumps are to be available should a fault occur with one of the pumps or during maintenance periods.

At least two portable surface water pumps are to be kept on-site at all times.

Level 2

If leachate or surface water becomes anaerobic in the leachate drains, sumps or in surface ponding a sucker truck is to be used to suck up any leachate or surface water and transport this off-site to an approved disposal facility.

Level 3

If the above mitigation is still not sufficient to prevent odour emissions from the collection and transfer of leachate to the leachate storage pond, then all composting shall cease on-site until an effective leachate collection and transfer system can be developed.

5.2.2.8 Leachate storage The leachate which is collected from the lime stabilised pad will be transferred to an appropriately sized and designed leachate collection pond. This lined pond will be used to hold leachate collected on-site prior to:

• irrigation to adjacent grazing paddocks managed by Envirofert; • treatment prior to being discharged into a wetland area; or • being sold as a liquid fertiliser.

Mitigation

29

Level 1

Leachate in the storage pond is to be aerated via mechanical aeration to ensure the dissolved oxygen content within the leachate pond does not fall below 1%.

At least two forms of mechanical aeration are to be present (i.e. a surface paddle wheel and a subsurface coarse or fine bubble aeration system) to provide an additional factor of safety.

The oxygen levels are to be measured in accordance with the methodology and frequency outlined in the OMP. Where records indicate that the trigger levels above are likely to be exceeded in the near future, then additional aeration is to occur (i.e. operate the secondary aeration device).

Where possible the holding time of leachate in the storage pond should not exceed 90 days.

The pond shall be emptied annually and sludge from the base of the pond shall be removed to prevent the anaerobic decomposition of this organic waste.

Level 2

Where the above mitigation is not sufficient to control odours being discharged from the site, sucker trucks shall be brought in to remove the leachate from the pond and dispose of in an approved facility.

The use of sucker trucks will continue until the oxygen level in the pond can be restored to above 1%.

Level 3

If Level 1 and Level 2 controls are still not preventing the emission of offensive odour from the leachate pond to below the level of detection at the site boundary, then all composting is to cease at the site until a more effective wastewater treatment plant can be designed, constructed and commissioned.

5.2.2.9 Leachate irrigation to land, discharge to wetland, or sale as liquid fertiliser All the leachate collected from the composting operation is to be transferred to one of three final uses (as listed in Section 5.2.2.8). This leachate is to remain aerobic during storage and be transferred from the storage pond as regularly as possible.

Mitigation

Level 1

No anaerobic leachate is to be irrigated to land, transferred to wetlands, or sold as liquid fertiliser.

The pumping systems used to transfer the leachate to its final use are to be maintained regularly. A secondary pump is to be kept on-site in the case of primary pump failure or maintenance.

Any irrigation lines or pipes used to convey leachate shall be regularly flushed with fresh water or a disinfectant chemical solution so as to prevent anaerobic decomposition of water in the lines, and hence odour release in the first stages of pumping.

Regular inspections of the irrigation fields and/or wetlands are to be conducted by site staff to ensure that there is no ponding or stagnation of leachate such that offensive odours are being released at these locations.

Level 2

If offensive odour is observed coming from this leachate disposal, then an investigation is to be conducted by site management as to alternative leachate disposal techniques/methodologies.

Alternative methods are to be implemented immediately.

30

Level 3

If Level 1 and Level 2 controls are still not preventing the emission of offensive odour from the leachate disposal system to below the level of detection at the site boundary, then all leachate is to be sucker trucked offsite.

All composting and leachate disposal is to cease at the site until a more effective wastewater treatment plant/leachate disposal system can be designed, constructed and commissioned.

5.2.3 Potential dust discharges There is potential for dust discharges from the composting operation. Discharge points include:

• The transport of raw materials and mature compost to and from the site. • Product handling activities: shredding, screening, mixing, and loadout. • Product storage stockpiles. • Vehicle movements on unsealed roads/tracks within the composting operation.

As dust from composting operations has a low risk of containing pathogenic fungal or microbial spores, then dust control is important on-site. Given the distance between the composting operation and the site boundary/nearest residential receptors, this is more critical for on-site worker health and safety than for off-site effects.

It is expected that dust emissions from the site will not travel more than 100m from the discharge point, however, for completeness NZ Air and Envirofert are proposing the following dust controls.

Mitigation

Level 1

All product transfer activities; dumping of raw materials, conveyors, front end loader transfer to screening plants, load out trucks and between the stages of the composting operation, is to be done in a manner that limits dust production. Where possible operators are to limit the drop height of material transfer activities.

When moving a particularly dusty product, wet down the product prior to moving.

Limit vehicle speeds on unsealed surfaces around the site to 20 km/hr. On hot, dry, windy days wet down internal roads and tracks (with a watercart or sprinklers).

Wet down the surface of stockpiles during hot, dry windy conditions.

Wet down dry material prior to putting it through the shredder or screening plants.

All raw product coming into the site and finished product leaving the site is to be transported in covered trucks.

All site staff are to be aware of dust emissions from the site. Should dust plumes be visible on-site, site staff are to notify site management so additional mitigation can be implemented.

Level 2

Use covers or shrouds on the shredders/screening plants.

Use fixed sprinklers or misters on the shredders/screening plants.

Install wind breaks across the site to reduce surface windspeeds across active disturbance activities or product stockpiles. Consider storing dusty products in three sided bunkers.

31

Use fixed sprinklers over dusty operations/stockpiles/haul routes.

Seal internal roads to prevent dust emissions from vehicle movements.

Level 3

Should nuisance dust be observed crossing the site boundary. Cease the dust producing activity until more effective dust management or controls can be implemented.

5.3 Managed Fill operation 5.3.1 Process description 5.3.1.1 Continuation of the Managed Fill operation A general overview of the proposed Managed Fill operation is included in Section 1.2.

The fill cells will be prepared by stripping the topsoil to form cell bunds, the cells with then be lined with plastic and clay. No more than 0.5 hectares of active fill area will be open at any one time to limit dust emissions from material disturbance activities and unconsolidated surfaces in the Managed Fill.

Managed Fill which meets the fill criteria will be trucked onto site via the main River Road site access point. Site staff will inspect the fill to ensure that it meets the Managed Fill acceptance criteria. Once the fill has reached the final profile level, progressive clay capping and rehabilitation with grassed top soil will occur.

Stormwater which falls on the Managed Fill will be collected in the southern stormwater retention pond (SRP) as marked on Figure 3. This water will be discharged via the scheme drains to the Kairoa Stream and ultimately to the Waikato River, provided it meets the discharge parameters.

It is expected that the three Managed Fill cells (F2, F3 and F4 marked on Figure 3) will be complete and fully rehabilitated within five years. Therefore, this activity is a relatively short duration.

Potential odour discharges from the proposed Managed Fill operation are negligible given the lack of organic material which is proposed to be deposited in the fill.

Dust emissions are expected to be inert, i.e. not contaminated, and therefore don’t present a health hazard. The particulate size is likely to be coarse and therefore not likely to travel far from the point of origin and less likely to contribute to respiratory effects. It is expected that any dust emissions from the site will only have the potential for nuisance dust effects beyond the boundary of the site, rather than health effects.

The current Managed Fill operation in F2 is not resulting in off-site nuisance odour or dust complaints. It is expected that the continuation of this activity will not result in any additional effects to off-site receptors. However good practice dust mitigation measures are proposed below to further limit the potential for any nuisance dust effects beyond the boundary.

5.3.1.2 Historic fill containment and management As discussed earlier there are two historic fill areas (F1 and F5 marked on Figure 3) which in the past received organic waste which is now decomposing within the cells and releasing odorous leachate and potentially landfill gas.

Envirofert have been conducting an extensive containment and treatment program to manage the potential effects of these historic landfill cells. Historically the leachate from these cells has ponded in low lying areas on the site and been the source of very intense sulphurous and anaerobic odours.

32

To reduce the volume and potential for leachate from these cells, they are being re-capped to stop stormwater entering the cell and driving leachate out. In addition, Envirofert have installed leachate two sumps (annotated as Leachate Sump 1 and 2 on Figure 3) in which collected leachate is to be actively pumped out to a tank storage facility which is to be located adjacent to the current compost leachate pond. This leachate is to be diluted via a venturi pumping system prior to irrigation to land. Alternatively Envirofert are investigating a water treatment facility, such that the landfill leachate can be treated to an acceptable level that it can be discharged to the Compost Site SRP and wetland which will discharge to the scheme drains and ultimately the Waikato River via the Kairoa Stream.

5.3.2 Potential odour discharges Odour discharge from the future Managed Fill operation is considered to be negligible given the lack of organic or odorous waste streams which are proposed to be accepted into the waste stream.

Odour discharge from the collection and treatment of the historic landfill leachate collection, storage and treatment will be managed as follows:

Mitigation

Level 1

The leachate collection sumps will be appropriately designed so as to collect all of the leachate being discharged from the historic cells, should another discharge point be observed, another sump/collection point will be designed and constructed.

The pumps in the leachate collection sumps shall be regularly operated so as to limit the volume of odorous, stagnant leachate sitting in these sumps or distribution lines.

The pumps and distribution lines shall be regularly inspected so as to ensure that they are operational and successfully transferring the collected leachate to the tank storage facility A secondary sump pump is to be kept on-site in the case of primary pump failure or maintenance.

The storage tanks are to be sealed such as to limit odour discharges during storage.

Any leachate in the storage tanks is to be incorporated into the compost leachate irrigation scheme or processed through the water treatment facility as soon as possible. It is not to be stored for more than 48 hours prior to being treated.

Level 2

Should intense offensive odour be observed coming from the sumps, chemical dosing of the sumps to reduce the odour discharge potential is to be investigated and implemented if practical.

Should offensive odour from the leachate collection, storage, or treatment be observable at the site boundary, sucker trucks are to be used to regularly collect the leachate from the sumps and dispose at an approved off-site disposal facility.

Level 3

Should Level 1 and Level 2 still not contain odour emissions from the leachate collection and processing, an experience landfill management engineer is to be engaged to design an appropriate leachate collection and processing facility for the site.

5.3.3 Potential dust discharges Potential dust discharge from the proposed Managed Fill operation can occur from:

• Vehicle movements to and from the site on the main access road.

33

• Material disturbance activities such as: o stripping topsoil and clay lining of the cells. o dumping Managed Fill. o shaping the fill profile. o capping the cell and rehabilitation with topsoil.

• Fugitive emissions from exposed surfaces.

Mitigation

Level 1

The speed limit on the main haul road is to be limited to 20 km/hr

Limit drop heights for dumping and material disturbance activities.

Regular use a watercart on the main access road and internal haul roads during hot, dry, windy conditions. (note that more than sufficient water supplies for dust mitigation are available from an on-site well).

Regular maintenance of the haul roads (with fresh washed aggregate) such that the surface of these roads have a low proportion of surface fines.

Regular use a watercart on the exposed unconsolidated areas of the Managed Fill during hot, dry, windy conditions.

Ensure that the water cart is maintained regularly such that efficient operation is maintained. Have access to a backup watercart in the instance that the watercart breaks down.

Level 2

Wet down loads/material prior to dumping and material disturbance activities.

Cease/limit material disturbance activities during adverse meteorological conditions, i.e. hot dry conditions where winds are blowing towards the nearest off-site receptors.

Level 3

Cease acceptance of Managed Fill to the site.

Cease material disturbance activities.

Hydroseed all exposed areas/dust sources on the site.

6 Assessment of Effects The proposed composting and Managed Fill operation has a lower potential for effect for a number of reasons:

• There are large separation distances from the composting operation to the nearest residential dwellings (particularly in all directions other than southeast of the site).

• The new ESAP composting operation will be undertaken in general accordance with US Federal EPA regulations for biosolids composting (40 CFR Part 503), the Compost New Zealand guidance for meeting NZS4454: 20054, and the criteria and good practice guidelines within NZS4454: 2005.

4 Compost New Zealand: A tool kit for NZS4450: 2005 The New Zealand Standard for Composts, Soil Conditioners and Mulches. 2007

34

• A high level of mitigation and monitoring is proposed, with multiple factors of safety to ensure that no offensive or objectional odour is detectable at the boundary.

• Envirofert have engaged a team of experts to ensure that the new operations at site will be conducted in accordance with all of the relevant standards and good practise guidance.

6.1 Good Practise Guides for composting The following standards and good practise guides have been used to design the proposed EASP composting operation. Envirofert consider that the proposed design and operating procedures are consistent with these guides and standards. In addition, this assessment has been conducted in general accordance with the guidance in these standards and guidelines.

• Waste Management Institute of New Zealand: Consent Guide for Composting Operations in New Zealand. 2009

• Compost New Zealand: A tool kit for NZS4450: 2005 The New Zealand Standard for Composts, Soil Conditioners and Mulches. 2007

• NZS4450: 2005 The New Zealand Standard for Composts, Soil Conditioners and Mulches. • US Federal EPA regulations for biosolids composting (40 CFR Part 503) • Department for Environment Food and Rural Affairs (DEFRA): Good Practice and Regulatory

Guidance on Composting and Odour Control for Local Authorities. 2009 • The Ministry for Environment: Good Practice Guide for Assessing and Managing Odour – 2016

6.2 Analysis of published separation/buffer distances Air quality separation or buffer distances are often used by regulatory bodies as an initial screening tool to assess if there is a potential for air quality related effects on neighbouring receptors/dwellings. If the nearest sensitive receptors are outside the separation/buffer distance, then it is unlikely that there will be any adverse air quality effects on these receptors, however they are within the distance then further assessment is required.

There is a number of published recommended separation distances from composting facilities:

• The South Australia (SA) Environmental Protection Agency (EPA) “Evaluation distances for effective air quality and noise management” August 2016

o 1,000 m for composting operations processing >200 tonnes /year • Victoria EPA: “Separation distances for large composting facilities” August 2012

o 1,000 m for composting 55,000 tonnes per annum • Netherlands Ministry of Infrastructure and Water: “Netherlands Emission Guidelines for Air”

2007 o 200 m for composting >20,000 tonnes per year.

• Emission Impossible report for Auckland Council: Air Quality Separation Distances for Industry 2012

o 500 m for composting greenwaste

Note that for many of the above separation/set back/buffer distance guidance documents there are a number of parameters which are used to calculate the appropriate distance. The range in setback distances for composting operations can be between 100 m and 2,000 m depending on the type of composting and the overall annual processing rates.

NZ Air have attempted to select the most appropriate distance based on the proposed Envirofert operation.

The most conservative published recommended separation distances considered appropriate for the proposed Envirofert operation are 1,000 m. In Table 2 there are five dwellings which are identified as

35

being at or within this conservative 1,000 m recommended separation distance R1, R3, R6, R8, and R9. However, all of the receptors are greater than 800 m from the proposed operation, and all of the five receptors are only downwind in one generic wind direction (South Westerlies).

Nevertheless, as some receptors are within this separation distance NZ Air have assessed the potential for effect in more detail.

6.3 Comparison of the proposed composting operation against other similar operations

6.3.1 Southern Horticultural Products NZ Air was engaged by Environment Canterbury to provide expert air quality review and technical input to the Southern Horticultural Products Ltd (trading as Intelligro) air discharge consent application (in 2015) and subsequent additional consent application (in 2017). Donovan van Kekem of NZ Air undertook a technical review of the air discharge assessment, undertook a site visit, and presented expert evidence at the resource consent hearing.

Intelligro, compost in excess of 50,000 m3 of raw materials per year. The feedstock for its composting process included bark and sawdust, chicken manure, spent mushroom substrate compost and pig litter. The composting method is static windrow composting with regular turning. Composting operations using these feedstocks and this methodology have a higher risk of generating adverse odour emissions (as described in the Composting New Zealand Consent Guide, and the DEFRA Technical Guidance of Composting Operations).

The Intelligro site has 13 residential receptors/dwellings within 250 m of the composting operation, a number of these are within 150 m.

This large scale, high risk composting operation has operated since 2015 without any verified odour complaints5.

Odour scout observations (undertaken in general accordance with the German VDI 3940 method) undertaken by both NZ Air personnel and air quality experts from Golder Associates determined that odour from the Intelligro operation was not detectable between 100 – 150 m downwind of the operation at the time when these assessments were conducted (multiple observations were made on different days and under different operating conditions).

The Intelligro operation conducts composting in accordance with the guidance in NZS4454-2005 and has a number of industry standard odour and dust control measures and processes.

6.3.2 Lenz Enterprises, Inc. Lenz Enterprises, Inc. (Lenz) operates an ASP style composting facility in Washington, USA. The feedstocks for this composting operation include:

• agricultural wastes including: herbivorous animal manure, paunch waste, shells, marijuana waste;

• ASTM compostable films and containers; • yard debris; • food waste; • food processing wastes; and • wood wastes.

5 Personal communications with Environment Canterbury’s consents team Dec 2018.

36

Lenz process in excess of 68,000 tonnes per annum and have a number of residential receptors within 300 m of the composting operation. Only one odour complaint has been received in the last 10 years of operation. The activity that caused this complaint was rectified immediately and has not reoccurred since.

Peter Moon of O2 Compost is acting as an advisory consultant to Envirofert, helping to design the proposed EASP methodology and operations plan. Mr Moon also designed the Lenz plant and has been involved in a large number of other composting operations which compost a wide range of organic feedstocks. The system provided by O2 Compost has a very high level of compliance with US regulations and offsite odour effect criteria.

6.3.3 Summary Both the Intelligro and Lenz operations demonstrate that large scale composting undertaken in accordance with good practice guidance and within the industry standards can result in no offensive or objectionable effects within 300 m of the operation.

Given the significantly larger separation distances between sensitive receptors and the proposed Envirofert composting operation, it is expected that the proposed operation will also be able to internalise any offensive odours produced to within the site boundary.

The high level, multifactor mitigation program is in excess of that undertaken at the above example composting operations, further reducing the potential for effects.

It is considered that these ‘real-world’ examples provide robust evidence that the proposed Envirofert composting operation will not result in odour or dust effects at the nearest sensitive receptors.

6.4 Differences between the historic operation and proposed operation – expected reduction in effects

Historic operations at the Envirofert site have resulted in a large number of nuisance odour effects associated with the composting and landfill emissions.

Poor plant design, staff training, operator error, and knowledge of the operation has been the primary cause of these off-site effects.

6.4.1 Composting operation Historically large portions of the composting operation have become anaerobic as a result of poor water drainage from the site and the composting piles getting ‘wet feet’ which results in no oxygen being present in the base of the pile as all of the available air gaps (porosity) are filled with water.

Furthermore, there has been very large volumes of mature compost (up to 40,000 m3) stored on-site which has been stored in outdoor piles well in excess of the recommended maximum 3 m height. Some of this compost has been more than 8 years old. The high piles result in the weight of the pile compacting the material at the base of the pile once again reducing the porosity of the pile and resulting in anaerobic conditions.

Feedstocks with a high potential for offensive odour or nuisance dust emissions have been received, stored and/or composted on-site, such as gypsum and de-packaged dairy products. These high-risk materials have not been well managed on-site and have resulted in poor compliance with the existing consent conditions.

Staff on-site have undertaken high risk odour emission activities, such as pile turning and material disturbance activities during adverse meteorological conditions (South Westerly winds). These operator

37

errors are a result of inadequate training and clear, practical and documented site processes and controls.

6.4.2 Historic landfill operation Historically materials which were not covered by the cleanfill consent criteria (such as gypsum, water treatment sludge, paper pulp etc) were received on-site and disposed of within the landfill operated by Envirofert. The historic landfill cells were not designed to receive this type of waste. This has resulted in leachate with a high sulfur and metals content. This leachate has drained to low lying areas of the site and formed ponds with very intense sulfuric odour emissions. This has resulted in off-site odour nuisance effects.

6.4.3 Proposed changes to the operation Envirofert has engaged a team of experienced professionals and experts to rectify the poor historic compliance of the site. Many of the proposed site changes have been implemented already and a number of changes are proposed to occur prior to replacement consents being granted.

The proposed process and operational changes have been discussed at length earlier in this report, a brief summary of the proposed changes is as follows:

- Prescribed and enforced composting feedstock and Managed Fill waste acceptance criteria. - Removal of all excess mature compost on-site. Future operations will involve only storing a

limited/manageable amount of mature compost on-site in covered sheds to prevent historic anaerobic conditions.

- Removal of all gypsum from the site and no longer accepting this high-risk waste. - Construction of a water impervious composting and processing pad to ensure all water and

leachate drain from the operation to be collected and disposed of appropriately. - A new composting system design (EASP) which has an established history compliance at other

large composting facilities. - Preparation of a very prescriptive OMP, which includes staff training, multilevel mitigation, and

industry standard good practice compost management. - Envirofert have committed to implement multilevel/multifactor of safety odour and dust mitigation