span - technical specification

SPAN - TECHNICAL SPECIFICATION

SPAN-TS 2006-04-R0

ICS: 13.030.20

Sludge/Residuals treatment - Sludge

thickener and dewatering

© Copyright 2020 Suruhanjaya Perkhidmatan Air Negara (SPAN)

A document developed by SIRIM for SPAN

SURUHANJAYA PERKHIDMATAN AIR NEGARA (SPAN) Suruhanjaya Perkhidmatan Air Negara (SPAN) is a technical and economic regulatory body for the water supply and sewerage services in Peninsular Malaysia and Federal Territories of Putrajaya and Labuan. The Commission regulates all entities in the water supply and sewerage services industry including public and private water supply and sewerage services operators, water supply and sewerage contractors, permit holders and suppliers of water and sewerage products. SPAN vision is towards a sustainable, reliable and affordable water service for all and with the mission to regulate the water services industry through fair, effective and transparent implementation of Water Services Industry Act 2006 (Act 655).

SPAN TECHNICAL SPECIFICATION SPAN Technical Specification (SPAN-TS) is developed according to SIRIM standardisation procedures, which are in line with international practices that ensure appropriate notification of work programmes and participation of interested parties. As a standards development organisation, SIRIM Berhad has extensive expertise in standards research and consultancy which helps industries and businesses meet local and international requirements and practices. SPAN-TS is developed from SPAN initiatives as a regulatory body for the water supply and sewerage services through collaboration with SIRIM which provides requirements, specifications, guidelines or characteristics that can be used to ensure that materials, products, processes and services are fit for their purpose. SPAN-TS is developed through consensus by established committee, which consists of experts in the subject matter. The use of this standard is mandatory, and it is open for adoption by regulators, government agencies, associations, industries, professional bodies, etc.

© Copyright 2020

For further info or enquiries on SPAN-TS, please contact: Bahagian Pembangunan Industri Suruhanjaya Perkhidmatan Air Negara (SPAN) Ground Floor, Prima Avenue 8, Block 3510, Jalan Teknokrat 6, 63000 Cyberjaya, Selangor Darul Ehsan Tel: 60 3 8317 9333/334/335 Fax: 60 3 8317 9336 E-mail:

© SPAN 2020 - All rights reserved i

Contents

Page Foreword ............................................................................................................................... ii 0 Introduction ............................................................................................................... 1 1 Scope ........................................................................................................................ 1 2 Normative references ................................................................................................ 1 3 Terms and definitions ................................................................................................ 2 4 Material ..................................................................................................................... 4 5 Sludge thickeners ...................................................................................................... 6 6 Sludge dewatering ..................................................................................................... 8 7 Service life ............................................................................................................... 13 8 Safety ...................................................................................................................... 13 9 Marking ................................................................................................................... 14 Annex A Test methods .................................................................................................... 15 Bibliography ........................................................................................................................ 20

ii © SPAN 2020 - All rights reserved

Foreword This SPAN-TS was developed by the Working Group on Sludge/Residuals Treatment - Sludge Thickening and Dewatering. This standard was developed with the following objectives: a) to provide a comprehensive standard that prescribes requirements for mechanical sludge

treatment equipment; b) to assist the industries to certify their products against a given standard; and c) to provide the regulatory bodies a standard for monitoring and qualifying products for use

in water treatment system and sewage treatment system. This standard will be subjected to review to reflect current needs and conditions. Users and other interested parties may submit comments on the contents of this standard for consideration into future versions. Compliance with this standard does not by itself grant immunity from legal obligations.

SPAN-TS XX:2020

© SPAN 2020 - All rights reserved 1

Sludge/Residuals treatment - Sludge thickener and dewatering

0. Introduction Sludge coming from treatment system contains high percentage of water which requires water reduction process to obtain solids prior to disposal. Sludge thickener and dewatering operations allow for this high reduction in sludge mass or volume. Handling of solid matters proven to be much easier and more cost effective as compared to handling sludge for disposal. In selecting a suitable equipment, many aspects must be taken into consideration including, but not limited to, the followings: — quality and quantity of the sludge to be treated;

— overall energy consumption of the system; — initial investment, maintenance and operating costs; — skill and infrastructure available; — safety of operations; and — specific local constraints or opportunities. Suruhanjaya Perkhidmatan Air Negara (SPAN) being the regulator for water and sewage activities in Malaysia recognises the importance of the efficiency of sludge and thickening system in water treatment and sewage treatment systems. This technical specification was developed as a guide to qualify equipment for these treatment systems. The technical specification provides the requirements on the material used for the construction of the equipment, the design criteria for thickener and dewatering equipment, the performance, acceptance criteria and test requirement for type of equipment, the service life for motors used in the system, the safety consideration during installation and operation of equipment, and the requirements on marking of equipment that need to be followed by equipment manufacturers.

1. Scope

This technical specification provides the requirements for sludge treatment equipment for the purposes of sludge thickener and dewatering of municipal wastewater and water treatment plant discharge.

2. Normative references

The following normative references are indispensable for the application of this standard. For dated references, only the edition cited applies. For undated references, the latest edition of the normative reference (including any amendments) applies.

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2 © SPAN 2020- All rights reserved

ISO 9906, Rotodynamic pumps - Hydraulic performance acceptance tests - Grades 1, 2 and 3 IEC 60085, Electrical insulation - Thermal evaluation and designation Standard Method 2540, Solids

3. Terms and definitions For the purposes of this standard, the following terms and definitions apply. 3.1 General 3.1.1 centrate Liquid leaving a centrifuge decanter or screw press after most of the solids have been removed. 3.1.2 dewatered sludge Sludge, in which the water content has been reduced by natural or mechanical means. 3.1.3 dissolved solids Substances remaining, after filtration and evaporation to dryness of a sample, under specified conditions. 3.1.4 dry solid content Ratio of the mass of total solids to total mass of sludge. 3.1.5 filtrate Liquid leaving a filter press, belt press, rotary drum thickener or belt thickener after most of the solids have been removed. 3.1.6 floating solids Floating layer of undissolved material and foam or scum on the surface of liquid. 3.1.7 settleable solids Portion of the initially suspended solids capable of being removed by sedimentation after a specified settling period under specified conditions. 3.1.8 sludge cake Sludge that has been sufficiently dewatered to be handled like a solid.

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3.1.9 sludge dewatering Process whereby wet sludge, usually conditioned by a coagulant, has its water content reduced by physical means. 3.1.10 sludge/residuals thickening Process by which the water content of sludge is significantly reduced, either by prolonged settlement aided by slow mechanical stirring and sometimes with the addition of chemicals, or by flotation of solids or centrifugation. 3.1.11 suspended solids Solids with a diameter greater than 0.45 µm that are suspended in water. 3.1.12 thickened sludge Concentrated sludge/residuals coming out from thickening process. 3.1.13 total solids (TS) Sum of dissolved, suspended, settleable and floating solids. 3.2 Wastewater treatment 3.2.1 municipal wastewater Water arising from any combination of domestic, commercial activities, surface runoff and any accidental sewer inflow/infiltration water. NOTE. Municipal wastewater includes collected stormwater and water discharged to the environment or sewer.

3.2.2 primary sludge Sludge removed from primary treatment unmixed with other recycled sludges. 3.2.3 sludge Mixture of water and solids separated from various types of wastewater as a result of natural or artifical processes. 3.2.4 waste activated sludge Sludge which is removed from an activated sludge process. NOTE. Waste activated sludge is also referred as surplus activated sludge or excess sludge.

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3.2.5 wastewater Water composed of any combination of water discharged from domestic premises, industrial or commercial premises, surface run-off and accidentally any sewer infiltration water.

3.3 Water treatment 3.3.1 residuals Accumulated settled solids separated from various types of water as a result of natural or artificial processes.

4. Material 4.1 General Materials used for the equipment shall be resistant to attack by the constituents of municipal wastewater and sludge, aerosols, sewage gases and atmospheric influences (e.g. micro-atmosphere) as appropriate and consistent with the relevant requirements. The client shall inform the equipment supplier of any special factors, such as the presence of septic sewage. If different materials are connected, detrimental galvanic corrosion shall be prevented. If load-bearing components are made of plastic material, detrimental effects of the environment (e.g. UV-radiation, temperature) shall be considered. Local conditions may require the use of particularly durable materials; this being subject to special agreement between contractor and client. Durability can be achieved by the use of materials inherently resistant to corrosion or by the application of a suitable coating. Where possible, anti-corrosion protection shall form part of the manufacturing process. Materials shall be selected to meet the requirements specified in the tender documents. Special materials shall be used at the clients’ request.

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4.2 Material for main component Additional requirements regarding materials for specific components is given in Table 1.

Table 1. Material for specific component of thickener and dewatering equipment

Type Component Material Minimum grade

Thickener

Centrifuge

decanter

Bowl Duplex stainless steel 1.4462/ SAF2205

Scroll Stainless steel Min SS304

Scroll flight Tungsten carbide-coated

spray

Tungsten carbide tiles Weld SS316

Belt thickener Belt Polyester/ Polypropylene

Roller Carbon steel ST 37.2 or

equivalent

Stainless steel SS304

Rotary drum Mesh Polyester/ Polypropylene

Stainless steel mesh SS304

Dewatering equipment

Belt filter press Belt Polyester/ Polypropylene

Roller Carbon steel ST 37.2 or

equivalent

Stainless steel SS304

Filter press Filter cloth Polypropylene/ Polyamide

Hydraulic

cylinder barrel

Structural steel • Cold drawn

tube GR20 with

heat treatment

• UNI Fe 510D

• 1.0576

• 1.0570

• 1.1191

Centrifuge Bowl Duplex stainless steel 1.4462/SAF2205


Scroll flight Tungsten carbide-coated

spray

Tungsten carbide tiles Weld SS316

Screw press Disc Stainless steel Min SS304


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5. Sludge thickeners 5.1 Type of sludge thickeners The following are the type of mechanical sludge thickeners covered in this technical specification. a) Centrifugal decanter

b) Gravity belt thickener c) Rotary drum thickener d) Other innovative products of thickener, subject to specification by SPAN The mechanical sludge thickener should a) be operated automatically with mechanism for manual override;

b) also include equipment needed for dosing of flocculant and flocculator tank (belt and

drum) and three polymer injection points (centrifuge decanter); c) use flocculant of food grade for water treatment; and d) be enclosed or located in a well-ventilated room for health and safety of operators and

to reduce corrosion. 5.2 Design criteria Design of mechanical thickening equipment shall take into account the requirements for control of odour, noise, vibration and explosive atmospheres; and, but not limited to, the followings. a) type and total solids concentration of the sludge to be thickened;

b) sludge properties required for downstream processes; c) availability of process water (quality, flow and pressure); d) compressed air required (flow and pressure) with auto-drain and dryer; e) daily net thickening capacity (the output mass of thickened dried solids), and maximum

daily thickening capacity, which includes any recirculation of solids (for example, solids return from a centrifuge);

f) maximum sludge feed rate, hydraulic (m3/h) and mass (kg DS/h); g) consumption of polymers or conditioning agents per mass of dried solids fed to the

equipment;

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h) dry mass concentration in the thickened sludge at the specified net capacity; i) dry mass capture rate attainable at the specified net capacity; j) consumption of polymers or conditioning agents at the specified net capacity; k) type of the mechanical equipment, relevant dimensions and specification of all relevant

materials and means of corrosion protection; l) nominal power consumption of all electrical drives, maximum and average power

consumption; m) failure indication at the control panel; n) automatic shut-down on failure inclusive of ancillary equipment;

o) automatic start-up and shut-down inclusive of ancillary equipment; p) consumption of process and clean water (including water for preparation and dilution of

polymers or conditioning agents); q) labour time required during regular operations; r) provision of sampling and maintenance; and s) provision of scour, backflushing and facilities for cleaning of equipment and accessories. Design criteria for thickener shall comply to the requirements given in Table 2.

Table 2. Design parameters for thickener

Parameter Type Requirement

Sludge type All i. Primary sludge

ii. Waste activated sludge

iii. Mixed sludge

Design basis Centrifuge decanter As rated by manufacturer

Gravity belt thickener Minimum 90 kg DS/m belt width

Rotary drum thickener Minimum 20 kg DS/m2.h

Hydraulic loading All As rated by manufacturer

Solid capture rate All i. Minimum 90 (Sewage)

ii. Minimum 95 (Water)

Energy consumption All Refer to Table 3

Water consumption Centrifuge decanter Maximum 10 % of hydraulic feed

Gravity belt thickener Maximum 3 m3/h.m

Rotary drum thickener Maximum 10 % of hydraulic feed

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Table 3. Energy consumption (without pumping and conditioning unit) for thickening

(initial sludge concentration of 0.7 % to 1.2 %

Type kWh/t DS kWh/m3

Gravity belt thickener 5 to 15 < 0.2

Disc/drum/desk thickener 5 to 20 < 0.2

Centrifuge decanter 80 to 220 0.6 to 1.4

5.3 Performance and test requirement The expected performance for sludge thickeners according to design shall be according to Table 4.

Table 4. Acceptance criteria and test requirement for thickener

Parameter Acceptance criteria Test method

Sewage Water

Solid loading As rated As rated Refer Annex A

Dry solid content, % DS Minimum 4 Minimum 4 APHA 2540

Solid capture rate, % Minimum 90 Minimum 95 Refer Annex A

Energy consumption,

kWh/m3

As rated As rated Refer Annex A

Water consumption As rated As rated Refer Annex A

Hydraulic loading As rated As rated Refer Annex A

Polymer consumption,

kg/tonne DS

1 - 4 1 - 4 Refer Annex A

6. Sludge dewatering 6.1 Type of sludge dewatering method The following are the type of mechanical sludge dewatering method covered in this technical specification. a) Belt filter press

b) Centrifuge decanter c) Filter press (chamber or membrane) d) Screw press

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The mechanical sludge dewatering should a) be operated automatically with mechanism for manual override; b) also include equipment needed for dosing of flocculant and flocculator tank (belt and

screw press) and three polymer injection points (centrifuge decanter); c) use flocculant of food grade for water treatment; and d) be enclosed or located in a well-ventilated room for health and safety of operators and

to reduce corrosion. The specifications of the dewatering equipment room shall be decided considering the following items. a) The room shall have adequate space for operation, inspection and maintenance of the

equipment. b) Ventilation, lighting and floor drainage shall be sufficient. c) The room shall be in a convenient location for carrying out the concentrated sludge. d) An overhead traveling crane, electric hoist, etc. shall be provided. 6.2 Design criteria Design of mechanical dewatering equipment shall take into account the requirements for control of odour, noise, vibration and explosive atmospheres; and, but not limited to, the followings. a) type and total solids concentration of the sludge to be dewatered; b) dewaterability characteristics of the sludge; c) sludge properties required for the final disposal; d) availability of process water (quality, flow and pressure); e) compressed air required (flow and pressure) with auto-drain and dryer; f) daily net dewatering capacity (the output mass of dewatered dried solids), and maximum

daily dewatering capacity, which includes any recirculation of solids (for example, solids return from a centrifuge);

g) maximum sludge feed rate, hydraulic (m3/h) and mass (kg DS/h); h) consumption of polymers or conditioning agents per mass of dried solids fed to the

equipment; i) dry mass concentration in the dewatered sludge at the specified net capacity;

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j) dry mass capture rate attainable at the specified net capacity; k) consumption of polymers or conditioning agents at the specified net capacity; l) type of the mechanical equipment, relevant dimensions and specification of all relevant

materials and means of corrosion protection; m) nominal power consumption of all electrical drives, maximum and average power

consumption; n) failure indication at the control panel; o) automatic shut-down on failure inclusive of ancillary equipment; p) automatic start-up and shut-down inclusive of ancillary equipment; q) consumption of process and clean water (including water for preparation and dilution of

polymers or conditioning agents); r) labour time required during regular operations; s) provision of sampling and maintenance; t) isolation device for wash water from the dewatered cake shall be provided and the wash

water to be discharged to the designated location. Wash water pressure shall be sufficient to wash mesh, belt, filter cloth, and bowl and scroll; and

u) automatic flushing or washing facilities shall be included.

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Design criteria for dewatering equipment shall comply to the requirements given in Table 5.

Table 5. Design parameters for dewatering equipment

Parameter Type Requirement

Sludge type i. Primary sludge ii. Waste activated sludge iii. Mixed sludge iv. Digested sludge v. Water treatment residuals

Design basis Centrifuge decanter As rated by manufacturer

Screw press Minimum 40 kg DS/hr/disc internal diameter

Belt filter press Minimum 90 kg DS/m belt width

Filter press (membrane) i. Sewage - Minimum 1 kg DS/m2.h

ii. Water treatment residuals - Minimum 1.25 kg DS/m2.h

Filter press (chamber) i. Sewage - Minimum 0.7 kg DS/m2.h

ii. Water treatment residuals - Minimum 1 kg DS/m2.h

Hydraulic loading As rated by manufacturer

Solid capture rate Minimum 95 (Sewage) Minimum 95 (Water treatment residuals)

Energy consumption Refer to Table 6

Water consumption Centrifuge decanter Maximum 10 % of hydraulic feed

Screw press Maximum 10 % of hydraulic feed

Belt filter press Maximum 6 m3/h.m

Filter press Maximum 20 % of hydraulic feed

Table 6. Energy consumption (without pumping and conditioning unit) for dewatering

systems (initial sludge concentration: 3 % to 8 %)

Type kWh/t DS kWh/m3

Filter press 20 to 50 0.7 to 1.2

Belt press 5 to 30 0.5 to 1

Screw press 5 to 30 0.2 to 1

Centrifuge decanter 15 to 80 1 to 3

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6.3 Performance and test requirement The expected performance for sludge dewatering method according to design shall be as given in Table 7.

Table 7. Acceptance criteria and test requirement for dewatering equipment


Sewage Water

Solid loading As rated As rated Refer Annex A

Dry solid content, % DS Minimum 20* Decanter:

i. Raw water

(river) -

Minimum 25

ii. Raw water

(dam/ORS) -

Minimum 20*

Filter press:

i. Raw water

(river) -

Minimum 35

ii. Raw water

(dam/ORS) -

Minimum 20*

Belt press:

i. Raw water

(river) -

Minimum 25

ii. Raw water

(dam/ORS) -

Minimum 20*

Screw press:

i. Raw water

(river) -

Minimum 25

ii. Raw water

(dam/ORS) -

Minimum 20*

APHA 2540

Solid capture rate, % Minimum 95 Minimum 95 Refer Annex A

Energy consumption,

kWh/m3

As rated As rated Refer Annex A

Water consumption As rated As rated Refer Annex A

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Table 7. Acceptance criteria and test requirement for dewatering equipment (continued)


Sewage Water

Hydraulic loading As rated As rated Refer Annex A

Polymer consumption,

kg/tonne DS

Maximum 4 Maximum 5** Refer Annex A

*If minimum value could not be achieved, mechanical dewatering should be carried out after

chemical conditioning (with lime, alum and/or ferric chloride or perlite/celite)

**Subject to type of polymer

7. Service life The service life of all motors shall be a minimum of Class 3 (see Table 8), unless otherwise specified. The service life of all bearings and gears for pumps, compressors, rakes, mixers, sludge dewatering machines and similar machinery and components shall be a minimum of Class 4 (see Table 8), unless otherwise specified.

Table 8. Acceptance criteria and test requirement for dewatering equipment

Service life class

1 2 3 4 5

Design service life, h

undefined 10 000 20 000 50 000 80 000

Motor coil insulation shall be of Class F (see IEC 60085).

8. Safety 8.1 The risk of accumulation of toxic or explosive gases shall be taken into consideration. 8.2 Appropriate measures for natural or mechanical ventilation shall be taken and/or explosion proof equipment shall be selected. 8.3 Sludge dewatering plants, in which gases and vapours can accumulate in noxious concentrations, shall be equipped with effective ventilation devices to exhaust gases and vapours from the source. 8.4 During sludge dewatering, hazardous gases such as ammonia, odour gases, hydrogen sulphide or methane may be produced depending on the process or conditioning method. 8.5 Hazardous gases may continue to be produced by dewatered sludge. Thus, rooms in which dewatered sludge is stored shall be well-ventilated.

SPAN-TS XX:2020


8.6 Mechanically operated sludge dewatering plants should be fitted with automatic cleaning equipment. 8.7 When inorganic chemicals are used, it is important to following best practices for chemical handling such as the use of gloves, glasses and protection clothes for operators and the provision of showers near the working area. 8.8 Handling of powder polymers requires anti-dust masks to be worn. This is not necessary for microspheres and emulsions. Polymeric solutions, diluted or not, have a high viscosity and quantities spilt on wet ground could involve an additional risk for the operators. 8.9 The noise level should be kept at <70 dB for belt and belt thickeners, belt and screw press, and for piston press (hydraulic distribution) but higher for centrifuges (85-90 dB) that requires noise insulation and/or specific staff protection equipment. 8.10 Centrifuges are vibrating machines and the level vibration shall be below 15-20 mm/s to avoid mechanical degradations. 8.11 Belt press shall be installed with emergency pull cord/lanyard and emergency stop button. 8.12 Filter press shall be installed with safety light curtains on both sides.

9. Marking Each equipment shall, at a minimum, be marked with the following information. a) Manufacture’s name or trademark b) Manufacturing serial number c) Manufacturing date (MM/YY) d) Equipment capacity:

i. Pressed volume and filtration area (filter press) ii. Solid load capacity, kg DS/h (centrifuge decanter) iii. Solid load capacity, kg DS/h (belt thickener/belt press) iv. Solid load capacity, kg DS/h (drum thickener) v. Solid load capacity, kg DS/h (screw press)

The markings shall be printed on plate and adhered to the equipment.

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Annex A (normative)

Test methods Annex A provides the test method to be conducted in order to comply with this Technical Specification. Figure A.1 is a typical process set-up for a thickener and dewatering equipment and demarcation on the test locations.

Key 1 Sludge feed 2 Thickened sludge/dewatered sludge 3 Centrate/filtrate produced 4 Polymer dosing 5 Wash water FM-1 Flowmeter, sludge feed (EM type) FM-2 Flowmeter, polymer dosing (EM/rotameter type) FM-3 Flowmeter, wash water (EM/rotameter type) P-1 Sludge feed pump P-2 Polymer dosing pump PPU Polymer preparation unit

Figure A.1. Typical diagram for thickener and dewatering equipment set-up

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A.1 Hydraulic loading Measure sludge feed flowrate, m3/h, using a flowmeter. Reading shall be made directly from the measuring equipment.

A.2 Solid loading A.2.1 Measure sludge feed flowrate, m3/h, using a flowmeter. Reading shall be made directly from the measuring equipment. A.2.2 Conduct test for dry solid on sludge feed using the appropriate method according to Standard Method 2540. Result given in % dry solid. A.2.3 Conduct test for density of sludge feed according to an established laboratory method. A.2.4 Calculation of dry solid loading, in kg DS/h, as follows:

Sludge flowrate x Density of sludge feed x Dry solid content

= m3

h x

kg

m3 x

kg DS

kg

A.3 Energy consumption, kWh/m3 A.3.1 Measure power use, kW, using a power meter according to method given in ISO 9906. Reading shall be made directly from the measuring equipment. A.3.2 Simultaneously, measure sludge feed flowrate, m3/h, using a flowmeter. Reading shall be made directly from the measuring equipment. A.3.3 Calculation of energy consumption, in kWh/m3, as follows:

Power use

Sludge flowrate

A.4 Water consumption Measure water flowrate, m3/h, using flowmeters (electromagnetic or rotameter). Reading shall be made directly from the measuring equipment.

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A.5 Polymer consumption, kg/tonne DS A.5.1 Measure polymer dosing flowrate, m3/h, using a flowmeter. A.5.2 Calculate the concentration of polymer in use, kg polymer/kg solution, based on actual operating condition (0.1 % - 0.4 %). A.5.3 Calculation of polymer consumption as follows:

Polymer dosing flowrate x Density x Concentration of polymer

Solid loading

kg polymer/h

kg DS/h

= kg polymer/kg DS

A.5.4 Convert result to kg polymer/tonne DS.

A.6 Solid capture rate, % A.6.1 Conduct test for dry solid for sludge feed, centrate/filtrate and cake using the appropriate method according to Standard Method 2540. Result is given in % dry solid. A.6.2 Measure sludge feed flowrate (m1), m3/h, using a flowmeter o. Reading shall be made directly from the measuring equipment. A.6.3 Measure centrate/filtrate flowrate (m3), m3/h, using one of the following methods: a) Method 1: Using mass balance by trial and error method. This method is applicable for

operation using all type of equipment.

b) Method 2: Manual measurement of centrate/filtrate flowrate using a calibrated volume. This method does not apply to filter press. Measurement shall be conducted with minimum of five flow ranges.

A.6.4 Calculation of solid capture rate, in %, as follows:

[1 −centrate/filtrate flowrate, m3

sludge feed flowrate, m1] x 100 %

For cases where continuous wash water mixed with filtrate (i.e. for belt thickener, belt press, rotary drum and screw press), the mass balance shall take into consideration the amount of wash water used for washing. Refer mass balance diagram (Figure A.2). For cases where the wash water does not mix with the centrate/filtrate (i.e. decanter and filter press), the wash water shall be excluded from the mass balance calculation.

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For cases where post-dilution of polymers is made, the amount of post-dilution water shall be measured and included in the mass balance calculation. For cases where the wash water is mixed with centrate/filtrate, the solid content tested may produce lower result due to dilution by the wash water. Ultimately, the solid capture calculated without taking into consideration the wash water flowrate will be higher compared with actual value. Example of calculation is given in Figure A.2.

SPAN-TS XX:2020


Bibliography [1] MS 1850: Part 13:2006, Water quality - Sampling - Part 13: Guidance on sampling of

sludges from sewage and water treatment works [2] ISO 5667-17:2008, Water quality - Sampling - Part 17: Guidance on sampling of bulk

suspended solids [3] ISO 6107-1:2004, Water quality - Vocabulary - Part 1 [4] ISO 6107-2:2006, Water quality - Vocabulary - Part 2 [5] ISO 6107-6:2004, Water quality - Vocabulary - Part 6 [6] ISO 6107-8:1993, Water quality - Vocabulary - Part 8 [7] ISO 20670:2018, Water reuse - Vocabulary [8] ISO/DTR 19995, Sludge recovery, recycling, treatment and disposal - Thickening and

dewatering [9] EN 12255-10:2000, Wastewater treatment plants - Part 10: Safety principles [10] BS EN 1085:2007, Wastewater treatment - Vocabulary [11] BS EN 12255-1:2002, Wastewater treatment plants - Part 1: General construction

principles [12] BS EN 12255-8:2001, Wastewater treatment plant - Part 8: Sludge treatment and

storage [13] IS 10037 (Part 2) - 1983 (2001), Requirements for sludge de-watering equipment - Part

2: Vacuum filtration equipment [14] IS 10037 (Part 3) - 1983 (2001), Requirements for sludge dewatering equipment - Part

3: Centrifugal equipment (Solid bowl type) [15] JIS B 9944-1987, Testing methods of activated sludge process equipments [16] JIS B 9945-1987, Testing methods of filtration equipments for dewatering [17] Design Guidelines for Sewage Works, Ministry of the Environment, Ontario [18] Malaysian Sewerage Industry Guidelines, Suruhanjaya Perkhidmatan Air Negara

© SPAN 2020 - All rights reserved

Acknowledgements SPAN and SIRIM STS would like to thank the organisations who have contributed their ideas, time and expertise in the development of this module. Mr Azamy Abdul Aziz bin Abdul Aziz (Chairman)

Suruhanjaya Perkhidmatan Air Negara (SPAN)

Ms Norfaizah Nasir (Technical Secretary) SIRIM STS Sdn Bhd Mr Ray Tan Alfa Laval (M) Sdn Bhd Mr Abd Haman Mohd Khairi ANQAS Certification Sdn. Bhd. Mr Talahah Othman BW Perunding Sdn Bhd Ms Mazurah Sulaiman/ Ms Nur Farah Farhana Mughni

HLA Associates Sdn Bhd

Mr Jason Ng Chan Hean/ Mr Ahmad Tarmizi Rahmat

Indah Water Konsortium

Ir. Hasrul Nizam Abdul Rahman Jabatan Kerja Raya Ir Huzaini Haji Husain Jabatan Perkhidmatan Pembentungan

(JPP) Mr Olgun Ugurdogan/ Mr Mohd Rizal Zakaria

Offshore Avenue Sdn Bhd

Ms Junainah Ahamah Pengurusan Air Selangor Sdn. Bhd. Mr Yeap Cheng Soon Perbadanan Bekalan Air Pulau Pinang Mr Wong Voon Yoong/ Mr Christopher Lim

PMI-Technology Sdn Bhd

Ms Wan Norisah Wan Awang/ Mr Roslan Azizan

SIRIM QAS International Sdn Bhd (Product Certification)

Mr Mohd Fauzely Mustapa Bakari SIRIM QAS International Sdn Bhd (Testing

Services) Ms Suriani Mohd Sukor Suruhanjaya Perkhidmatan Air Negara

(SPAN) Prof Dr Shaliza Ibrahim Universiti Malaya

© Copyright 2020

All rights reserved. Unless otherwise specified, no part of this module may be reproduced or utilised in any form or by any means, electronic or mechanical, including photocopying, recording or otherwise, without prior written permission from SPAN.

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