sewerage services 2012report technical - regulation &...

Sewerage ServiceS Technical reporT2012

The regulaTion & SuperviSion BureauSewerage Services Technical Report 2012

01

introduction The activities of the wastewater sector are defined by Emirate law as:

(a) collection of wastewater from premises;(b) treatment and processing of wastewater; and(c) disposal of the products of wastewater treatment.

This report provides an overview of the sector’s performance in 2012 and is based on the regulatory submissions and reports received by the Bureau. It is focussed on the performance of ADSSC, the sector’s main service provider, but also describes the contribution of other licensees.

The report also highlights the work of the Bureau’s Wastewater Team to support the efficient operation and development of the sector in 2012.

This is the first time that this report has been published and recognises the growing confidence in the data collected and reported as the sector matures and regulations and reporting practices become embedded.

The acronyms and abbreviations used in this document are listed in page 11.

Sewerage services are provided throughout the emirate by abu Dhabi Sewerage Services company (aDSSc).


02

Sewerage services

licensees Sewerage services include the collection and treatment of wastewater and disposal of the products of wastewater treatment.

These services are primarily designed to protect public health and minimise the environmental impact of wastewater but also generate a range of valuable products which can be used as a source of water, nutrients and energy to support the Emirate’s sustainable development goals.

The Bureau enforces a legal framework designed to:

a. minimise the risk to public health and the environment;

b. minimise public nuisance from sewerage services;

c. maximise the social and economic benefits of sewerage services; and

d. develop public confidence in recycled water and biosolids disposal.

Sewerage services are provided throughout the Emirate by Abu Dhabi Sewerage Services Company (ADSSC) with the support of a number of other private operators that deliver contracted treatment capacity to ADSSC or collection, treatment and disposal facilities for small, remote developments such as labour camps and hotels.

Major wastewater licensees

In 2012, the Bureau had four major sewerage services licence holders:

a. Abu Dhabi Sewerage Services Company (ADSSC);

b. Higher Corporation for Specialized Economic Zones (ZC);

c. Al Etihad Biwater Waste Water Company (EB); and

d. Al Wathba Veolia Besix Waste Water Company (VB).

Figure 1 illustrates the operational areas and major treatment plants operated by ADSSC and the other major wastewater licence holders. EB and VB hold treatment only licences and provide treatment capacity to support ADSSC’s operations.

ZC operate a collection, treatment and disposal system for the ICAD zones close to Abu Dhabi.


03

Figure 1: Major wastewater licensee operations

aDSSc main plants (over 7Mi/day)

etihad Biwater plants - Wathba 1 and Saad

Veolia Besix plants - Wathba 2 and al hamah (not commissioned)

Zonescorp

abu Dhabi

al ain

western regionMadinat Zayed

Mirfa

Zonescorpwathba-2

wathba-1

Mafraq

Zakher

al Saad

al hamah*

Small-scale wastewater licensees

Any sewerage services licence holder managing less than 10,000m³/d is described as small-scale. In 2012, 11 small-scale licensees held time-limited development licences, as listed in table 1.

Table 1: Small-scale licensees

licensees issue date Licensed flow (m³/d)

average daily flow (m³/d)

TDIC - Qasr Al Sarab 23-Aug-08 620 320

ADFEC (Masdar) 20-Jan-10 1,500 300

Samsung Corporation - Ruwais 18-Feb-10 500 100

Manazel Real Estate 30-Mar-10 1,000 900

EMAL 13-Oct-10 700 230

Sorouh Real Estate Company PJSC 15-Feb-11 2,120 1,600

Hyundai KPIZ- (stopped operation June 2012) 20-Feb-11 1,000 1,000

Al Tamouh Investments LLC - Wadi Adventure 19-Jul-11 50 50

Hyundai Engineering and Construction Co. Ltd - Braka 1-Oct-11 3,000 1,733

Al Naboodah National Contracting Group LLC 6-May-12 100 0

Dhafra Beach Hotel 1-Jul-12 500 280

Total 11,090 6,513

The total average daily flow managed by the systems under the control of small-scale licensees was 6,513m³/d in 2012 or 0.8% of the total daily flow managed by the sector.

* Not commissioned in 2012


04

Figure 2: Small-scale licensee operations

al ain

western region

TDic (Qasr al Sarab)

Samsung

hyundai - Braka

Dhafra Beach hotel

Tamouhal naboodah

aDFecManazel

emalhyundai - KpiZ

Sorouh

wastewater assets In 2012, ADSSC operated 35 wastewater collection, treatment and disposal systems across the Emirate. Most of these underwent significant changes, eg. increase in flow or delivery of new capital projects, to support the Emirate’s sustainable development plans.

EB completed commissioning of two new treatment plants which provided 35% of the treatment capacity in the Emirate and VB commissioned one new treatment plant which provided 25% of the Emirate’s capacity.

A small number of permanent connections were added to ZC’s system, including the Emirate’s largest tanker reception facility. In 2012, ZC managed approximately 2% of the total daily flow generated in the Emirate.

collection systems

Wastewater collection is defined as “the connection of premises to the sewerage system and the transportation of wastewater from premises or customers to the wastewater treatment system” and a collection system is defined as a “system consisting (wholly or mainly) of sewerage pipes, pumping stations,

tankers and other plant and equipment owned or operated by the licensee and used for the transportation of wastewater from premises or customers to the wastewater treatment system”1.

The key components of the collection systems operated in the Emirate are:a. gravity sewers;b. pumping stations; and c. pumping mains.

In 2012, ADSSC operated 288 pumping stations ranging in size from small local stations to large terminal pumping stations rated at over 300l/s. 23 new pumping stations were commissioned to extend the capacity of the networks in Abu Dhabi and Al Ain.

The delivery of the Strategic Tunnel Enhancement Program (STEP), designed to relieve hydraulic overloading on Abu Dhabi Island and the surrounding mainland, progressed with the completion of 75% of the 41 kilometres of deep tunnel sewer. Work also started on the link sewers that will connect the existing sewer system to the deep tunnel sewer and on the pumping station required to lift all flows from the tunnel into the ISTPs at Wathba.

1 ADSSC Sewerage, Wastewater Treatment and Disposal Licence ED/L01/016

abu Dhabi


05

Figure 3 illustrates the year-on-year increase in the length of sewer network operated by ADSSC. It highlights the changing proportion of pumping mains, trunk sewers (those greater than 400mm in diameter) and local sewers (those smaller than 400mm in diameter).

The total operational network length in 2012 was 6,800km an increase of 1.3% from 2011 which included a significant 28% increase in trunk sewer length.

The growth in network length was due to the adoption of some mega development assets and the delivery of projects designed to extend the capacity of the networks in Abu Dhabi and Al Ain.

Treatment systems Wastewater treatment is defined as “the reception of wastewater from the collection system, the treatment of wastewater and delivery of the resulting products and by-products to the disposal system” and a wastewater treatment system is defined as a “system consisting (wholly or mainly) of pipes, pumping stations, tankers and other plant and equipment owned or operated by the licensee and used for the wastewater treatment”1.

In January 2012 EB’s Wathba 1 and Al Saad ISTPs entered full operation followed by VB’s Wathba 2 treatment plant in February. These new ISTPs extended the treatment capacity in the Abu Dhabi Region by 600Ml/d and Al Ain city by 70Ml/d.

This additional capacity allowed ADSSC to rationalise the provision of treatment capacity in Al Ain and Abu Dhabi by closing a number of small temporary MBR treatment plants and hydraulically re-rating Mafraq STP to 260Ml/d from 340 Ml/d.

In late 2012, ADSSC took responsibility for the treatment plants on Yas Island (12Ml/d) and Masdar City (1.5Ml/d).

All these changes resulted in a slight decrease in available capacity across the Emirate, as illustrated in table 2.

Table 2: Major licensee treatment capacity

2011 2012

Sewage treatments plants (no.) 40 37

Total installed capacity (Ml/day) 1,236 1,155

Disposal systemsWastewater disposal is defined as “the safe and sustainable disposal, recycling or sale of various products produced from the wastewater treatment system, including but not limited to treated effluent and biosolids” and a wastewater disposal system is defined as a “system consisting (wholly or mainly) of pipes, pumping stations, tankers, and other plant and equipment owned or operated by the licensee and used for disposal” .

In 2012, the disposal of recycled water and biosolids in the Emirate was almost exclusively carried out by ADSSC. The company operated transmission networks to transfer recycled water to end-users or environmental disposal sites and all treated biosolids (45,160 tons) were transported by road to landfill sites.

The total length of recycled water network increased significantly in 2012 with the commissioning of the network that connected Al Saad ISTP to the Al Ain Municipality irrigation network and the partial commissioning of an extension of the network serving the mainland area of Abu Dhabi, as show in table 3.

Table 3: Key recycled water disposal assets

region Disposal asset data 2011 2012*

aD island and Mainland

Recycled water network length (Km)

Number of recycled water pumping stations

Recycled water storage capacity (Ml)

74.2

0

0

143.2

0

0

al ain and remote areas




24.8

16

25.1

82.7

17

96.7

Western region




30.7

11

53.3

46.6

12

60.8

* estimated data from 2012 AIS

total length of pum ping main

length of sewers > 400mm

length of sewers < 400mm

1,000

0

2,000

3,000

4,000

5,000

6,000

7,000

2010

net

wo

rk le

ng

th (K

m)

2011 2012*

5,387

751

428

1 ADSSC Sewerage, Wastewater Treatment and Disposal Licence ED/L01/016

Figure 3: collection network length

5,254

717

373

5,459

792

549


06

System performance

This section reports on key performance measures for the collection, treatment and disposal systems operated by ADSSC. The performance indicators have been selected to demonstrate changes in ADSSC’s effectiveness and efficiency in providing sewerage services.

collection system performanceperformance indicator one: Sewer collapses per 100km

A sewer collapse is a “break or collapse in any gravity sewer, pumping main or vacuum system main which forms part of the licensee’s sewerage system and causes an interruption to the service”2.

The number of collapses per 100km of sewer is a good indicator of the effectiveness of collection system asset management activities and the performance of the operator in managing third party activities close to sewer systems. Between 2011 and 2012, sewer collapses for ADSSC decreased, with rates in Abu Dhabi and Al Ain primarily attributed to third party construction activity.

Table 4: Sewer collapses per 100km

Sewer collapses per 100km 2011 2012

Abu Dhabi Region 1.53 1.01

Al Ain City & Remote Area 1.02 0.93

Western Region 0.61 0.78

performance indicator two: Sewer blockages per 100km

A sewer blockage is “any partial or total blockage in any gravity sewer, pumping main or vacuum system main which forms part of the licensee’s sewerage system and causes an interruption to the service”2.

The frequency of blockages per 100km indicates the effectiveness of operation and maintenance activities in the collection system. ADSSC use a benchmark figure of 100 blockages per 100km of network per year.

The data presented in table 5 reflects the blockage rate for ADSSC sewers and does not include the blockages on private sewer systems cleared by ADSSC. There has been a significant increase in the blockage rates recorded in the Abu Dhabi Region during 2012. This may be due to a change in O&M contractor and clarification of reporting requirements.

Table 5: Sewer blockages per 100km

Blockages per 100km 2011 2012

Abu Dhabi Region 34 66

Al Ain City & Remote Area 2.2 2.2

Western Region 1.2 0.78

2 ADSSC AIS template 2012.


07

Treatment system performanceTable 6 shows an increase of 15.38% in the total annual flow and average daily flow handled by the major licensees between 2011 and 2012.

performance indicator three: STps running over 90% of hydraulic capacity

The number of STPs running at over 90% of their hydraulic capacity is an indicator of the effectiveness of ADSSC’s asset management activities for treatment assets such as planning and forecasting or operation and maintenance.

Table 7 shows the number of treatment plants operated by ADSSC in each of its three regions and the number running within 90 % of their hydraulic capacity during 2011 and 2012. The table highlights that there are more works running at 90% of their rated capacity in 2012 than in 2011. However the most significant change is the removal of Mafraq STP from the over capacity list in Abu Dhabi Region.

The growth in wastewater flows has been attributed to an increase in contributing population driven by Government policies and the commissioning of a number of mega developments in the Abu Dhabi Region.

Figure 4 illustrates the proportion of wastewater managed by the major licensees in 2012, highlighting the important role played by the ISTPs and the relative scale of the treatment operations carried out by ADSSC across the Emirate.

Table 6: Flow to treatment

regionAnnual flow Ml Ave daily flow Ml/d % change

2011 to 20122011 2012 2011 2012

ADSSC + ISTPs 241,256 276,952 661 759 14.8

ZonesCorp 4102 6155 11 17 50

Total 245,359 283,107 672 776 15.38

Table 7: STps running over 90% of hydraulic capacity

region2011 2012

no. of STps no. > 90% capacity no. of STps no. > 90% capacity

Abu Dhabi Region 6 2 9 1

Al Ain and Remote Areas 16 5 16 6

Western Region 12 7 12 9

Total emirate Flows by company

aDSSc Flowby region

38% ADSSC

35% Biwater (2 plants)

25% Veolia

2% ZonesCorp

57% Abu Dhabi Region

13% Western Region

30% AL Ain and Remote Areas

Figure 4: Proportion of flow handled by major licensees


08

Disposal system performanceperformance indicator four: proportion of recycled water sent to reuse

The proportion of recycled water sent to reuse activities is an indicator of the effectiveness of the sector’s capacity to support the Emirate’s sustainable development goal and maximise use of a valuable product. Figure 5 illustrates the proportion of recycled water generated in the Emirate that is either reused on ADSSC’s own sites, dispatched to end-users for reuse, for example municipality irrigation systems, or discharged to the environment.

The disposal of recycled water varies from region to region and reuse activities in Al Ain were very effective compared to those in Abu Dhabi and the Western Region, as shown in table 8. Lower recycling performance in these areas was reportedly caused by constrained infrastructure

in Abu Dhabi and limited demand from end-users in the Western Region.

Furthermore, in the Abu Dhabi Region, all the recycled water produced by Zonescorp was discharged to the environment.

Performance indicator five: Recycled water quality

The Recycled Water and Biosolids Regulations 2010 require the quality of any recycled water supplied to end-users or discharged to the environment to meet the requirements of Schedule A of the regulations. Schedule A is based upon a risk-based approach to quality and includes a range of parameters which vary depending on the proposed end-use or discharge.

Table 9 summarises the performance of all STPs treating more than 7Ml/d, which accounts for over 95% of the recycled water produced in the Emirate. The table highlights the performance of each STP against three key parameters; faecal coliforms, biochemical oxygen demand and total suspended solids.

During 2012, the ISTPs’ performance was deemed excellent with overall compliance in excess of 97% for the key parameters. The performance of ADSSC’s main STPs was found to be more variable with, for example, periodic issues of meeting the microbiological quality at Mafraq and the TSS standard in Mirfa and Madinat Zayed.

The regulations are designed to promote the safe and sustainable reuse of recycled water and biosolids throughout the Emirate by developing relevant information on the quality of these important products. Furthermore, robust, transparent reporting will highlight compliance difficulties and allow licensees to develop effective operational or project-based solutions to drive year-on-year improvements.

Table 8: recycled water reuse activities by region 2012

region rW produced (Ml) reused onsite (Ml) Reused offsite (Ml) environmental (Ml) % reuse

Abu Dhabi Region 201,494 4,588 75,423 126,026 40

Al Ain 58,025 1,676 55,072 1,276 98

Western Region 13,080 1,898 6,709 4,473 66

Total 272,599 8,162 137,204 131,775 52

Table 9: Key recycled water quality data for major STps

co

mp

any

Site

regs sch’d a1.1 stds

Faecal coliforms cFU/100ml BoD

5 (aTU) mg/l Total suspended solids

(TSS) mg/l

no. samples % pass Geo-

meanno.

samples % pass Mean no. samples % pass Mean

aD

SS

c

Mafraq P1 187 68 0.1 248 100 1.57 251 98 4.3

Al Zakher P1 181 93 2.9 240 100 3.3 299 99 1.27

Mirfa P1 44 95 0.1 51 98 1.65 51 86 6.16

Madinat Zayed P1 41 90 0.4 50 98 1.85 50 82 6.48

eB Wathba 1 P1 29 97 0.1 366 100 1.22 366 97 4.62

Al Saad P1 264 100 1.6 263 100 1.53 306 100 1.27

VB Wathba 2 P1 32 100 0.01 366 99 1.46 366 99 3.55

Zc ICAD P3 12 100 298.4* 366 99 8.64 52 100 8.06

49% RW reused offsite

3% RW reused onsite

48% Environment

* Faecal coliform data reported for ZonesCorp is an arithmetic mean not geomean.

Figure 5: recycled water disposal outlets in 2012


09

wastewater operational incidents

In 2012, seven operational incidents were reported to the Bureau under the Incident Reporting Regulations 2008, five by ADSSC and two by VB.

Most incidents were caused by contractors not controlling construction activities in a way that minimised damage to collection networks and six of them required further investigation, as summarised in table 10.

Table 10: operational incidents 2012

Date of incident

license holder

Type of incident nature of the incident consequences root cause

02-Jan-12 ADSSC Sea, Land Third party contractor preforming drilling work hit one of ADSSC’s strategic pumping mains on AD mainland

Wastewater discharge to the surrounding ground. Wastewater diverted to the sea via storm drains during peak hours

The contractor was working without work permit from ADSSC

31-Jan-12 ADSSC Land An ADSSC contractor was preforming drilling which damaged an ADSSC collection network in Mafraq

Wastewater discharged to the surrounding ground and groundwater. Physical damage to property

Drilling struck a sewer causing damage

03-Feb-12 ADSSC Land Trial hole work by an ADSSC contractor damaged an ADSSC collection network in Al Ain

Wastewater on the surrounding ground, groundwater & physical damage to the property

During trial work a sewer has been exposed

29-Mar-12 ADSSC Land ADSSC contractor damaged an ADSSC collection network while carrying out excavation work for RW pipeline in Al Shamakha

Raw sewage flooded and accumulated at the work location

Excavation work hit main sewer

12-Oct-12 ADSSC Water Raw Wastewater discharged to storm water network and ultimately Musaffah channel

Pollution of Musaffah Channel

Increase of flow due to development in the catchment and delay to capital project to mitigate the increase in flows

17-Oct-12 Al Wathba Veolia Besix Waste Water Company PJSC

By pass Wastewater bypass at the filtration unit

Wastewater discharged into a bypass line into the environment

Power failure leading to wastewater bypass at the filtration unit


10

Launch of Low-Risk Trade Effluent codes of practiceOver 3,000 restaurants and cafés and more than 300 small-scale laundries are registered in the Emirate, all of which discharge non-domestic wastewater to licensee networks. These discharges are deemed to pose a low-risk to the receiving collection and treatment systems but must be controlled.

To minimise the regulatory burden associated with controlling these types of discharge, the Bureau issued two Code of Practices (CoPs) that define the operational and management controls for wastewater discharges from restaurants and laundries through its powers under the Trade Effluent Control Regulations 2010.

wastewater regulations quality standards consultationEvery two years, the Bureau is obliged to assess whether the quality standards in the Trade Effluent Control Regulations 2010 and Recycled Water and Biosolids Regulations 2010 reflect best international practice and local requirements. In 2012, the Bureau carried out its first review of these quality standards through a consultation with the Wastewater Regulations Review Panel. The standards were deemed fit for purpose and the Bureau is not proposing any changes to the regulations.

wastewater tankeringThe management and control of wastewater tankering activities became a high-profile issue for the Emirate in 2012. The Bureau conducted a consultation with a range of stakeholders, including government agencies and licensees, to establish current practices and the scale of issues associated with wastewater tankering.

The consultation identified a range of controls for tankering used by government agencies and some overlaps between regulatory responsibilities. The consultation also identified a number of issues that required further investigation including tanker specifications, fee structures, customer registers and wastewater dumping. This will lead to future work in 2013.

Defining regulatory roles and responsibilitiesThe Bureau worked with the EAD, CWM, EHS Centre and Abu Dhabi Municipality to review the regulatory framework for wastewater activities in the Emirate.

The project identified that the various frameworks were aligned but that there were a number of gaps and overlaps which should be addressed through closer co-operation between the agencies.

wastewater Flow Monitoring code developmentRecent changes in the wastewater sector have introduced a range of commercial and regulatory requirements to establish accurate wastewater flow data.

The Bureau consulted the sector on the options for establishing controls for flow monitoring practices that could ensure consistent behaviour across the sector and promote confidence in any flow data captured by licensees. The sector endorsed the Bureau’s preferred approach of developing a self-regulation code of practice and the Bureau appointed GHD to develop a code of practice for flow metering activities that sets minimum requirements for installation, operation and management of flow monitoring system.

Key projects


11

glossary

aDFec abu Dhabi Future energy company

aDSSc abu Dhabi Sewerage and Services company

BoD5 (aTu) The biochemical oxygen demand of wastewater during decomposition occurring over a 5 day period.

cFu/100ml colony forming unit per 100 millilitre

cwM centre of Waste Management

eaD environment agency of abu Dhabi

eB al etihad Biwater Wastewater company

ehS abu Dhabi environment, health & Safety centre

eMal emirates aluminium

icaD industrial city of abu Dhabi

iSTps independent sewage treatment plants

km kilometre

KpiZ Khalifa port and industrial Zone

l/s litre per second

m meter

MBr membrane bioreactor

m3/day meter cube per day

mg/l milligram per litre

Ml/day mega litre per day

Ml mega litre

mm millimetre

o&M operation and maintenance

rw recycled water

STep Strategic Tunnel enhancement program

STp sewage treatment plant

TDic Tourism Development and investment company

TSS Total suspended solids

vB Veolia Besix Waste Water company

Zc Zonescorp

Zonescorp higher corporation for Specialised economic Zone

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