Cent ra l Environmental Author i ty Partsara Mawatha

Maligawatta New T o w n Colombo 10 SRI I.ANKA.

T e l e p h o n e No: 449455/6, 437487/8/9 Fax No: 01-446749

ISBN 955-9012-04-5

PRINTED B* LIMTt D MFRCKAN1 S LTO CCH.OMBO U

GOVERNMENT OF THE DEMOCRATIC SOCIALIST REPUBLIC OF SRI LANKA

I N D U S T R I A L P O L L U T I O N C O N T R O L G U I D E L I N E S

N o . 5 — Dairy Industry

C E N T R A L E N V I R O N M E N T A L A U T H O R I T Y Ministry of Environment and Parliamentary Affairs

INDUSTRIAL POLLUTION CONTROL GUIDELINES

/ QQf - > J w> 'y

No 5 Dairy Industry I

CEA Library

Prepared by the Centra^ Environmental Authority With Technical Assistance from The Government of the Netherlands

1992/93

First edition 1992

"OQ4430J

VAO> .. •

Published by the Central Environmental Authority Parisara Mawatha Maligawatta New Town Colombo 10 SRI LANKA

Telephone No:449455/6, 437487/8/9, 439073/4/5/6 Fax No: 01-446749

This document may be reproduced in full or in part with due acknowledgement to the Central Environmental Authority

ISBN 955-9012-04-5

Front Cover Design & concept by W A D D Wijesooriya Artwork by Somasiri Herath

024/waddw/guideS

PREFACE

The Government of Sri Lanka is promoting rapid industrialization in order to create better employment opportunities for the growing work force of the country, and to increase the income level of the people. At the same time the Government is conscious of the fact that some of the existing industries significantly contribute to the deterioration of the quality of the environment in the country, especially in the urbanised and industrialized areas. Ill-planned industrialization will no doubt accelerate the process of environmental degradation.

The Government has, therefore, introduced environmental legislation to enhance environmental protection and pollution control. The Central Environmental Authority (CEA) is the lead agency in the implementation and enforcement of the environmental legislation. It has initiated various programmes for the protection of the environment, with special attention on industrial pollution control.

The CEA has requested technical and financial assistance from the Government of

The Netherlands for a number of projects in this field.

As a result technical assistance for a programme which consist of the following projects was provided by the Government of The Netherlands:?

1. Development of environmental quality standards on the basis of designated

uses . A

2 . Development and updating of emission/discharge standards and pollution control guidelines for selected priority industries

3 . Feasibility studies on pollution control for priority industries or industrial

sectors 4 . Study tour to The Netherlands for Sri Lankan officers involved in compliance

procedures in the Environmental Protection Licensing Scheme (enforcement)

Under project No 2 above, industrial pollution control guidelines, were prepared the following eight(8) industrial sectors, considered as major polluters in Sri Land

1. Natural Rubber Industry 2 . Concentrated Latex Industry 3 . Desiccated Coconut Industry 4 . Leather Industry 5. Dairy Industry 6. Textile Processing Industry 7. Pesticide Formulating Industry 8. Metal Finishing Industry

The main objective of the preparation of these guidelines was to assist the Central Environmental Authority in industrial pollution control with special reference to the introduction of the Environmental Protection Licensing Scheme.

In the preparation of these guidelines attention was focused on the generation of liquid, gaseous and solid wastes and their impacts on the environment. In the process aspects of industrial counselling, including in-plant measures to prevent and reduce waste generation and measures to improve occupational safety and health were also considered. Alternative methods were discussed for end-of-pipe treatment of liquid . gaseous and solid wastes .

Existing wastewater discharge quality standards were considered and intermediate standards ( with respect to the phased installation of treatment systems) were proposed in these guidelines.

The guidelines were mainly prepared on the basis of data available on industrial pollution and its abatement in sri Lanka, from studies and reviews carried out in the past and from missions to Sri Lanka specifically carried out for preparation of these guidelines.

The project was directed by Mr K G D Bandaratilake. Director of the Environmental Protection Division of the CEA, and coordinated by Mr W A D D Wijesooriya, Senior Environmental Scientist of the CEA. The CEA project team consisted of Mr C K Amaratunga and Mr S Seneviratne, Environmental Officers.

Technical assistance was given by a team of BKH Consulting Engineers, Comprises Dr I van der Putte (team leader), Mr J G Bruins and Mr H J F Qreemers.

This document contains pollution control guidelines for Dairy Industry.

G K Amaratunga Chairman Central Environmental Authority

Paae

1. INTRODUCTION 1

2. PRODUCTION OF DAIRY PRODUCTS 2

2.1 Production data 2 2.2 Production processes 2

3. WASTE PRODUCTION AND ENVIRONMENTAL IMPACTS 4

3.1 Wastewater production 4 3.2 Solid wastes 4 3.3 Air pollution 5 3.4 Environmental impacts 5

4. INDUSTRIAL COUNSELLING 6

4.1 Introduction 6 4.2 In-plant pollution control 6 4.3 Improvement of occupational safety and health 6

5. POLLUTION ABATEMENT METHODS 8

5.1 Introduction 8 5.2 Wastewater treatment alternatives 8 5.3 Wastewater treatment system choice 12

6. DISCHARGE AND EMISSION STANDARDS 13

6.1 Effluent quality standards 13 6.2 Emission standards 14

7. REFERENCES

Annex I - Standards for industrial emissions in Thailand

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INTRODUCTION

The Sri Lankan dairy industry processes annually about 80 million litres milk into dairy products such as milk, milk powder, cheese, butter, ice cream and yoghurt.

The dairy industry consists of regional milk collection centres and a number of large and small scale dairy plants.

The dairy industry generates significant quantities of liquid wastes, of which the discharge may cause serious water pollution. Only one dairy plant operates a wastewater treatment plant. All other factories discharge their wastewater into nearby drains, streams or marshy lands.

This document gives general guidelines regarding pollution control for the dairy industry including in plant pollution control, improvement of occupational safety and health and wastewater treatment methods. A pollution control programme to be implemented in stages, with intermediate and final effluent quality standards is proposed.

2. PRODUCTION OF DAIRY PRODUCTS

2.1 Production data

In Sri Lanka 81 million litres milk per year are collected in 85 regional milk collection centres, which are located all over the country. They distribute the milk to the milk processing plants (dairies).

Presently about 15 dairies are in operation, of which 4 plants are considered as large scale, with a processing capacity over 7.5 million litres milk per year. The other 11 plants have a-smaller production capacity.

In the dairy plants raw milk is processed into pasteurized milk, sterilized milk, ice cream, butter, cheese, yoghurt, condensed milk and milk powder.

All dairy plants are privately owned. Presently none of the 4 large scale plants operates at its full production capacity. They process on the average 40,000 I milk per day.

2.2 Production processes

In the dairy industry various products are manufactured, including pasteurized and sterilized milk, butter, cheese, yoghurt, ice cream and curd. Most dairy plants manufacture a variety of dairy products, but also dairies with only one product, e.g. milk powder exist.

The raw material for dairies is raw milk, which is taken to rural milk collection centres, and from there transported in bowsers to the dairy plant. A typical dairy factory which produces various dairy products except milk powder is divided into the following production sections:

raw milk reception milk pasteurisation section cream pasteurisation + mix preparation pasteurized milk filling section sterilized milk section

final products section (yoghurt, butter, cheese, ice cream)

Raw milk reception In this section bowsers are unloaded and the raw milk is stored in chilled tanks.

<

Milk pasteurisation section Cream is separated from the milk and taken to the cream pasteurisation section. Milk is pasteurized and subsequently stored for further processing. ^

Cream pasteurisation and mix preparation

Cream is pasteurized, deodorized and homogenized and subsequently stored in vats. For the production of ice cream the pasteurized cream is kept in vats. Cream which is used for yoghurt production is stored in separate yoghurt mix storage vats. Pasteurized cream is mixed with pasteurized milk for the production of butter and cheese.

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Pasteurized milk filling section

In this section the pasteurized milk is stored and packed.

Sterilized milk section For the production ot sterilized milk, pasteurized milk is consecutively pre-sterilized, homogenized and reheated. Bottles are washed, tilled with pre-sterilized milk and subsequently transported to the sterilization tower.

Final products section In this area products such as ice cream, yoghurt, curd, butter and cheese are produced from mixtures of pasteurized cream and pasteurized milk. For example, cheese is produced through addition of a "starter" to the milk under controlled temperature conditions. For the production of curd, raw milk is pasteurized batch-wise. An acid or enzyme is then added to form lactic acid which, in turn, results in curd formation.

In all sections described above the equipment is daily cleaned with water containing strong alkalis or acids.

Production ot milk powder

The processes for milk powder production are quite different from the other dairy production processes. Raw milk is sterilized and subsequently evaporated by spraying. All equipment in the sterilization and evaporation sections is daily cleaned with water, which contains small amounts of nitric acid or caustic soda. In the so-called dry section milk powder is manufactured and packed. In milk powder factories also coconut powder can be produced since the production processes are quite similar.

3. WASTE PRODUCTION AND ENVIRONMENTAL IMPACTS

3.1 Wastewater production

The large scale dairy factories producing consumption milk and other dairy products are each generating a wastewater flow of about 100 m 3 /day. One large scale milk powder factory is reported to discharge 220 m 3 of wastewater per day.

The main sources of wastewater are:

washing and cleaning of tanks, trucks, cans, piping and other equipment; spills from leaks, overflows, equipment malfunctioning, careless handling; wastage of spoiled products, returned products or by-products such as whey; detergents and other chemicals used for cleaning; domestic wastewater.

A typical composition of wastewater from dairies is given in Table 3.1 for the following sources:

A - wastewater from the pasteurization and sterilization section B - wastewater from bowser washing and the production of ice cream and

yoghurt

Table 3.1 Composition of two wastewater streams from a dairy (Ref. 5)

Parameter Source A Source B Total (sec text) (see text) (A + B)

BOD (mg/l) 1,100 175 545 COD (mg/l) 2,800 400 1,360 Suspended solids (mg/l) 600 50 270 PH 5.0 5.4 5 - 5.5 Flow (m 3/d) 45 67.5 112.5

The wastewater is mainly organic in nature. Dairy wastewater acidifies rapidly, since the milk sugar converts to lactic acid in the absence of oxygen. The resulting low pH causes casein to precipitate and decompose into a heavy black sludge 1 which has a high BOD. Raw milk contains about 2.5% of casein.

3.2 Solid wastes i Small amounts of solid waste are generated by dairy industries mainly consisting of discarded packing material (paper, cartons, aluminium/metallized foil).

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3.3 Air pollution

Some atmospheric pollution is generated in the dairy industry by steam boilers, which are mostly fuelled with furnace oil. These boilers are used for sterilization and pasteurization purposes.

3.4 Environmental impacts

In Sri Lanka dairies are mostly discharging their wastewater without any treatment (with one exception) into nearby streams or rivers. These discharges result in low dissolved oxygen concentrations in the receiving stream or river. Suspended solids cause a build-up of bottom deposits. This is particularly objectionable because the solids are organic in nature. Bottom deposits of organic sludge cause a heavy oxygen demand on the receiving water. Anaerobic decomposition may produce hydrogen sulphide and other intermediate products, causing bad odours and adverse effects to aquatic life.

The acidic character of the wastewater may have an adverse impact on aquatic life due to increased toxicity. Water supplies and wastewater treatment systems may be damaged due to increased corrosiveness. Secondary effects such as the increasing solubility of heavy metals may also, result in increasing toxicity to aquatic life. The combination of aforementioned effects may make the receiving water unfit for drinking and bathing purposes.

Emissions of black smoke and flue gases from steam boilers may cause nuisance to neighbouring residents.

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4. INDUSTRIAL COUNSELLING

4.1 Introduct ion

The industrial counselling procedures are directed towards the introduction of environmentally sound technology ("clean technology"). Clean technologies contribute to more efficient production methods by saving energy and raw materials and reducing emissions to air, water and soil. They include good housekeeping measures, modification of production processes and raw materials use, as well as recycling of waste and process waters.

Industrial counselling aims at environmentally sustainable industrial development by promoting a combination of in-plant pollution control and end-of-pipe treatment in order to protect the environment and to optimize the conservation of energy and raw materials.

Additional advantages of the application of cleaner production processes are the reduction of safety hazards and the impiovement of occupational health. Therefore, initial investments aimed at pollution control become more cost effective.

In this chapter in-plant pollution control measures and methods to improve occupational safety and health are proposed.

4.2 In-plant pol lut ion control

In-plant pollution control techniques should be applied in order to reduce the strength and volume of the final discharges. The waste load from dairy factories could be reduced by good housekeeping methods and by integrated process measures. The most commonly used measures include:

a comprehensive waste monitoring system which enables effective waste management; an equipment maintenance programme to minimize product losses; optimum equipment utilization; product quality control programme to prevent unnecessary loss of products to waste streams; development of (re-)use methods for waste products; constant improvement of processes, equipment and systems.

4.3 Improvement of occupational safety and health

Occupational safety and health aspects concern physical, chemical, biological and mental hazards and stresses present in the working environment. The improvement of occupational safety and health aims at the protection of workers at the workplace and its immediate environment against hazards such as heat, dust, noise, vibration, toxic chemicals, airborne pollutants, mechanical hazards, explosions and radiation. It also includes the adaptation of installations and processes to the physical and mental capacity of the workers.

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In the dairy industry, the main safety hazards are cuts and abrasions caused by numerous rotating machine components, bursting separators, bursting bottles and flying glass, and falls on slippery floors. Health hazards are diseases carried by animals. Other hazards may include burns from strong alkalis and acids used for cleaning. Fires and explosions may occur in the drying chambers of milk powder plants.

Measures which could be adopted to improve occupational safety and health in the dairy industry include the following:

floors should be non-slip and frequently cleaned; good housekeeping practices; open milk vats should have guards or railings to protect workers from falling into them; fire extinguishers should be easily accessible; there must be adequate passage way for carters and workers; mechanical equipment must have guards to protect workers from injury from moving components. Bottling machines should be fitted with screens to protect from flying glass. Workers should be provided with eye and face protection; regular inspection and maintenance is essential in preventing accidents and injuries from machines, steam boilers, steam receivers, etc.; protective clothing should be worn by the workers where necessary (gloves, aprons, boots, eye and face protection); disinfectants should be used frequently in order to prevent contamination of the workers with diseases carried by animals; chambers for the spray drying of milk should be fitted with relief vents. The workers should not be exposed to a dust level above 5 mg/m 3 .

5. POLLUTION ABATEMENT METHODS

5.1 Introduction

In dairies the amount of solid waste is negligible. Methods of solid waste disposal are therefore not further discussed.

Some air pollution is generated from steam boilers which are generally fuelled with furnace oil.

The wastewater is mostly combined into one flow and discharged directly into the nearest stream. Due to adverse impacts of directly discharged dairy wastewater on the water quality and because of the enforcement of industrial wastewater discharge standards by the Sri Lankan Government dairy plants will be enforced to install wastewater treatment facilities. A number of alternative wastewater treatment facilities, which can be installed in stages, is described in the following section.

5.2 Wastewater treatment alternatives

Dairy wastewater is polluted mainly with bio-degradab!e organic matter. Therefore it is usually treated by biological wastewater treatment methods.

The combined wastewater flow from a typical large-scale dairy plant in Sri Lanka has the following characteristic (the Milco dairy, ref.5):

Daily flow 100 m 3 /d pH 5.2 BOD 560 mg/l COD 1,400 mg/l

Three different biological wastewater treatment methods are described in the following sections.

5.2.1 Ponds systems

If sufficient land area is available a ponds system can be applied for the treatment of dairy wastewater..Various types of wastewater treatment ponds exist: anaerobic ponds, facultative ponds, aerated ponds and maturation ponds. Usually series of different ponds are used for wastewater treatment.

Two alternative pond systems are described below:

Alt. 1 - anaerobic pond - facultative pond - maturation pond

Alt. 2 - anaerobic pond - facultative aerated pond - maturation pond

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The anaerobic pond is considered as first stage or pre-treatment. The combination of facultative pond or aerated pond followed by a maturation pond is carried out as secondary treatment. Each of these ponds systems is discussed below.

Pre-treatment: Anaerobic pond

In the anaerobic pond the organic matter in the wastewater is biodegraded by anaerobic bacteria into gases, such as methane, hydrogen' sulphide, ammonia and carbon dioxide. Solids settle into a sludge layer at the bottom of the pond which has to be removed periodically.

The most important' design parameters are (for Sri Lankan conditions, average temperature is 27° C)

Organic volume loading rate 300 g BOD/m 3.d Depth 2.5-4 m BOD removal efficiency 70-90 %

Anaerobic ponds may cause odour nuisance. For this reason these ponds should be located at sufficient distance from residential areas (at least 500 m).

The anaerobic pond should have the following dimensions:

Volume 200 m 3

Depth 4 m Area (excluding embankments) 50 m J

It is estimated that the effluent of the anaerobic pond has the following composition:

pH 7 - 8 COD 400 mg/l BOD 150 mg/l

Alternative 1 - Facultative pond + maturation pond

In the facultative pond organic matter is biodegraded aerobically in the upper layers of the pond. Oxygen for this process is mainly supplied by algae. Some anaerobic biodegradation of settled organic material takes place at the bottom of the facultative pond.

The most important design parameters for facultative ponds are:

Organic surface loading rate 330 kg BOD/ha.d Depth 1.2 m BOD removal efficiency 80-90 %

Facultative ponds are usually applied in series of 2 or more ponds. The last pond functions as a polishing or maturation pond, in which micro-organisms die off and settle to the bottom. A design example is given hereafter, on the basis of the wastewater characteristics, given above.

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Facultative pond

Area (excl. embankments) 500 m* Depth 1.2 m Volume 600 m 3

Maturation pond

Area (excl. embankments) 200 m J

Depth 1.5 m Volume 300 m 3

Effluent quality

COD 150 mg/l BOD 20 mg/l

Alternative 2 - Facultative aerated pond + maturation pond

An alternative for the facultative pond is a mechanically aerated pond. In this type of pond oxygen for aerobic biodegradation is supplied by mechanical aerators. There are two types of aerated ponds, the completely mixed aerated pond and the facultative aerated pond. A design example of a facultative aerated pond system is given below.

In a facultative aerated pond only the top layers are kept aerobic, by means of mechanical aerators. Suspended solids settle to the bottom of the pond, where anaerobic biodegradation takes place. The most important design parameters for facultative aerated ponds are:

Required power input 1.75 W/m 3 pond volume BOD removal efficiency 80-90 % Depth 2.5-4 m

Facultative aerated ponds are usually followed by a maturation pond.

Dimensions of the ponds are:

Facultative aerated pond

Required power input 0.75 kW Volume 400 m 3

Depth 4 m Area 100 m 2 (excl. embankments)

Maturation pond

(see facultative ponds)

Effluent quality

COD 150 mg/l BOD 20 mg/l

I 5.2.2 Activated sludge system

In the activated sludge system the wastewater is led into an aeration tank, where it is mixed with floes of aerobic micro-organisms (activated sludge). The mixture of activated sludge and wastewater is aerated vigorously.

i Organic substances in the wastewater are absorbed by the active micro­organisms, which biodegrade the organic matter, utilizing the breakdown products as a substrate for growth and formation of new cells. As a result the sludge quantity in the aeration tank is increased. Micro-organisms die-off in the aeration

( tank, the dead cells being oxidized into inert material (mineralization).

The mixture is led from the aeration tank into a sedimentation tank where the floes settle into a sludge. Part of this sludge is returned to the aeration tank, in order to maintain a constant concentration of activated sludge in it. The remainder of the sludge (surplus sludge) has to be removed. The surplus sludge is often de watered in a sludge drying bed to decrease its volume.

Controlled disposal of the wet sludge in agricultural lands is also possible.

High load activated sludge systems with a high loading rate of organic matter per quantity activated sludge (kg BOD per kg sludge solids per day) and low load activated sludge systems are used in wastewater treatment.

The advantages of low load systems in comparison with high load systems are higher reliability, better BOD removal, production of a mineralized sludge and simpler operation. One type of low load activated sludge system is the oxidation ditch system.

The most important design parameters for low load activated sludge systems (oxidation ditch) are:

0.15 kg BOD/kg sludge dry solids

4 kg/m 3

2.5 kg 0 2 / k g BOD 95-98 %

1.5-2.5 m

It is estimated that the effluent of an oxidation ditch system has the following quality:

BOD 15 mg/l COD 120 mg/l

organic sludge loading rate sludge dry solids content in aeration tank oxygen requirement BOD removal efficiency depth (depends on aerator type)

5.2.3 Rotating Biological Contactors System

The Rotating Biological Contactors (RBC) system consist of a series of biorotors, a biorotor being a central horizontal shaft to which a contact surface has been attached. The biorotor is fitted into the tank, into which the combined wastewater, after pretreatment including equalization, is led. The submersion depth of the biorotor in the tank is 40% of the biorotor diameter. The biorotor rotates slowly, about 1-2 rotations per minute, and a film of sludge, containing aerobic micro-

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organisms develops on the contact surface of the biorotor. While rotating in the tank the biorotor lifts up a quantity of wastewater, causing intensive contact between wastewater, micro-organisms and oxygen from the air.

The sludge film absorbs organic matter, which is biodegraded aerobically in the process of substrate utilization by the micro-organisms for growth and formation of new cells. The excess sludge is washed off from the contact surface.

The effluent of the biorotor tanks is led into a sedimentation tank in which the excess sludge settles.

Important design parameters for the RBC system are:

Biorotor surface loading rate 10 g BOD/m 2.d Peripheral rotation speed 12.5 m/min Biorotor submersion depth 24 - 40 % of diameter BOD removal efficiency 90-95 %

Before entering the RBC units the wastewater from the dairy should be collected in an equalization tank in order to create a continuous equal flow to the RBC units. A RBC system consists of an equalization tank, RBC units, sedimentation tank and sludge disposal facilities.

The estimated effluent quality is:

BOD 40 mg/l COD 300 mg/l

The effluent quality can be improved by increasing the number of RBC's in the system.

5.3 Wastewater treatment system choice

The selection of a wastewater treatment system for a dairy plant depends on a large number of factors, including size and location of the plant, availability of land, presence of suitable land for wastewater disposal (irrigation), sludge disposal, and the characteristics of the receiving waters.

If sufficient land area is available the anaerobic/facultative ponds system will be selected since this system has the lowest costs and the most simple operation. If the anaerobic/facultative ponds system cannot be applied, one of the other systems has to be chosen. The oxidation ditch system is the most expensive system but has the best effluent quality.

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6. DISCHARGE AND EMISSION STANDARDS

6.1 Effluent quality standards

Presently no specific quality standards for the discharge of dairy wastewater exist in Sri Lanka. However, the Government' of Sri Lanka has set general quality standards for the discharge of effluents into inland surface waters. These standards are given in Table 6.1.

Table 6.1 Quality standards for the discharge of effluents into inland surface water, Sri Lanka

pH 6.0 - 8.5 Temperature (max. °C) 40 BOD5 (at20°C, mg/l) 30 COD (mg/l) 250 oil, grease (mg/l) 10.0 phenolic compounds (mg/l) 1.0 total suspended solids (mg/l) 50 cyanides (mg/l) 0.2 sulfides (mg/l) 2.0 fluorides (mg/l) 2.0 chlorine (mg/l) 1.0 arsenic (mg/l) 0.2 cadmium (mg/l) 0.1 chromium (mg/l) 0.1 copper (mg/l) 3.0 lead (mg/l) 0.1 zinc 5.0 mercury (mg/l) 0.0005 nickel (mg/l) 3.0 total nitrogen (mg/l) 50 pesticides undetectable

The discharge standards for the BOD and the COD given in Table 6.1 can be fulfilled by means of one of the wastewater treatment alternatives described in Chapter 5.

Since the installation of complete wastewater treatment systems for the dairies creates problems, intermediate standards are proposed for the operation of a first stage treatment system consisting either of rotating biological contactors or of an anaerobic pond (see Table 6.2). In the case of the RBC-system, second stage treatment may consist of the addition of more RBC's. The anaerobic pond can be extended with more ponds in the second stage, constituting a complete ponds system (see Table 6.3).

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Table 6.2 Proposed intermediate and ultimate standards for the dairy wastewater quality

intermediate standard ultimate standard (Stage 1) (Stage 2)

BOD (mg/l) 150 30 COD (mg/l) 400 200

Table 6.3 Dairy wastewater treatment in a staged programme

Stage 1 Stage 2

RBC RBC-addition

Anaerobic pond facultative pond + maturation pond (alt.1) aerated pond + maturation pond (alt.2)

6.2 Emission standards

In Sri Lanka no standards have been set for emissions of gaseous, liquid or solid pollutants into the atmosphere. However, oil fired boilers, used in the dairy industry for the production of steam, generate emissions containing nitrogen oxides, sulphur oxides and soot. Therefore it may be useful to refer to existing "Industrial Emission Standards" for specified sources, as proposed for Thailand for the Thailand Ministry of Industries. These standards are given in Annex I (Ref. 7).

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REFERENCES

1. Environmental Guidelines World Bank Environmental Department, 1988

2. Industrial Water Pollution, N.L. Nemerow, 1978

3. Environmental criteria (or the siting of industries in urban areas, National Building Research Organisation, Colombo, 1987 )

4. Occupational safety and health guidelines, World Bank, Environmental Department, 1988

5. Intermediate solution for treatment of dairy wastewater, BKH Consulting Engineers, 1988

6. Survey of industrial production, 1990, Sri Lanka Department of Census and Statistics, 1991

7. Laws and Standards on pollution control in Thailand, 2nd ed., Environmental Quality Standards Division, Office of the National Environmental Board, Thailand, 1989

ANNEX I

STANDARDS FOR INDUSTRIAL EMISSIONS IN THAILAND

1AL E N V I R O N M E N T A L A U T H L

Annex I Standards for industrial emissions in Thailand (Ref. 7)

Substances Sources Proposed Standard

Values

Particulate - Boiler & furnace Heavy oil as fuel 0.3 g/Nm 3

Coal as fuel 0.5 g/Nm 3

- Steel manufacturing 400 mg/Nm 3

- Cement plant and calcium 400 mg/Nm 3

carbide plant - Rock and gravel aggregate 400 mg/Nm 3

plants (production capacity more than 50,000 tons/year)

- Other source 500 mg/Nm 3

Smoke opacity Boiler and furnace not exceed 40% Smoke opacity Ringlemann scale

Aluminium Furnace or smelter (dust) 300 mg/Nm 3

(Al) 50 mg/Nm 3

(dust) 300 mg/Nm 3

(Al) 50 mg/Nm 3

Alcohol any source 0.05 Ib/min Aldehyde any source 0.05 Ib/min Ammonia gas plant 25 ppm Antimony any source 25 mg/Nm 3

Aromatics any source 0.05 Ib/min Asbestos any source 27 jig/Nm 3

Arsenic any source 20 mg/Nm 3

Beryllium any source 10 iig/Nm 3

Carbonyls Burning refuse 25 ppm Chlorine any source 20 mg/Nm 3

Ethylene from production or by usage 0.03 Ib/min Ester any source 0.05 Ib/min Fluorine any source 0.3 lb/ton P , 0 5

200 mg/NrTr Hydrogen Chloride any source 0.3 lb/ton P , 0 5

200 mg/NrTr Hydrogen Fluoride any source 10 mg/Nm 3

Hydrogen Sulphide any source 100 ppm Cadmium any source 1.0 mg/Nm 3

Copper any source dust 300 mg/Nm 3

(Cu) 20 mg/Nm 3

dust 300 mg/Nm 3

(Cu) 20 mg/Nm 3

Lead any source dust 100 mg/Nm 3

(Pb) 30 mg/Nm 3

0.1 mg/Nm 3 Mercury any source (Pb) 30 mg/Nm 3

0.1 mg/Nm 3

CO any source 1,000 mg/Nm 3

so2 H 2SO, production Other activities:

500 ppm

- Bangkok and its vicinities 400 ppm - other area 700 ppm

NO. Combustion source 1,000 mg/Nm 3 NO. HN0 3 production and others

2.00O: mg/Nm 3

Nitric acid any source 70 mg/Nm 3

Organic material any source 0.01 Id/min Phosphoric acid any source 3 mg/Nm 3

Sulfur trioxide any source also in 35 mg/Nm 3

combination with H 2 S 0 4 as H 2 S 0 4

Sulfuric acid any source 35 mg/Nm 3

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