cp case manual[1]

8/3/2019 CP Case Manual[1]

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PROBLEM STATEMENT

Industries within the SADC region are struggling to address the problem of resourceconsumption and waste generation and also conform to prevailing environmental

legislation as well as emerging green markets. One such industry is the Beef CorporationLtd (BeefCo) whose major environmental concerns are water and air pollution. Therewas a lack of understanding of the Cleaner Production concept which should haveassisted the company to identify and address these concerns whilst meeting its businessinterests.

CASE SITUATION

BeefCo is a large meat producing company. The company was established in 1957 and issituated along a major river in a commercial capital.

The main products of the company include cut beef, steak, beef sausages, pork, porksausages, ham sausages, polony, dripping (fats), minced meat, and by products which aresold locally, and hides and skins which are sold internationally. The raw materials arebasically cattle, pigs, sheep, and goats. They are mainly sourced from cattle ranches andlocal farmers. Other main production inputs are, water, diesel and electricity.

In its daily operations BeefCo makes an extensive use of resources such as water andenergy. Large volumes of water are used for cleaning equipment and floors. Thewastewater contains blood and some meat trimmings. The processing of by productsproduces bad smell resulting in air pollution particularly when processing decomposedmaterial. Energy is used for cooling purposes as well as for the production of hot water

and steam.

People living around the company have for a long time complained about the bad smellthat is attributed to the activities of the company. Wastewater from the companysprocesses contains blood, fat, pieces of meat, extracts of manure and stomach contents.This wastewater has a high Biochemical Oxygen Demand (BOD) and fatty matters (oils).During the period between January to August 1999, the effluent from the wastewatertreatment plant had average values of BOD and fatty matter of 603 mg/l and 1744 mg/lrespectively. These values are above the City Assembly trade effluent limits of 400 mg/lfor BOD and 200 mg/l for fatty matter. The company pays on average US$711 per monthto the City Assembly in fines as a result of noncompliance to trade effluent limits.

Abattoirs are identified as large water consumers. Large volumes of water are used forcleaning equipment, floors and meat products. BeefCo uses approximately 1929 cu. m ofwater per month. Average specific water consumption during period under review wasabout 3102 litres per head of cattle and 935 litres per pig and approximately 8990 litres per tonne of by-product. The water consumption was very high compared to bestavailable technologies which use about 1000 litres per cattle and 300 litres per pig.(UNEP, 1999)

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Energy consumption was also high. The company obtained heat from a boiler that useddiesel oil as the source of energy. A lot of energy was wasted from steam due to leaks,uninsulated pipes and other hot surfaces. Approximately 350 Giga Joules (GJ) of heatenergy was lost during the period under consideration. This was an equivalent of

approximately 750 litres of diesel per month. This translated to an expenditure of US$667per month.

It was the companys wish and ambition to remain profitable while accounting for theenvironmental impacts of its activities. This challenge required a solution that wouldenable BeefCo to maximise its economic gains. It was against this background that thecompany in conjunction with the Southern African Network for Training and Researchon the Environment (SANTREN), carried out a Cleaner Production Assessment in orderto answer three basic questions:

Where were the waste emissions generated ?(source identification).

Why were those waste streams generated? (cause evaluation). How could those streams be avoided ? (option generation).

STAKEHOLDERS

The activities of BeefCo were influenced directly or indirectly by its variousstakeholders. The company's stakeholders could be split into two categories as follows:

Internal:

Top Management decision-making and commitment with respect to adoptionand implementation of CP activities.

Section Managers eg. Audit Assistant, Production Supervisor, Stores Supervisor,Electrical and Refrigeration Supervisor, Stock Holder, Accounts Clerk.

Production Staff who are involved in resource usage and waste generation.

Waste treatment and handling staff e.g. in wastewater treatment plant and the by-product processing plant.

External

Shareholders - owners of the company.Responsible government ministries these are policy formulating bodies.

Local Authority i.e. the City Assembly enforcement of legislation onenvironment.

External Assistance Providers external consultants from SANTREN. Consumers both local and international (whether products are produced

following set acceptable standards)

Community affected by emissions and other wastes generated.

Chamber of Commerce and Industry an umbrella body for industries.

International Donor Organisations DANIDA provided project funding and alsoinvolved in capacity building.

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Academic and Research Institutions e.g. SANTREN promoting CP activities inthe SADC region.

Waste Hauliers City Assembly responsible for collection, treatment and disposalof waste.

CLEANER PRODUCTION CASE STUDY PROCEDURE

In carrying out this case study the CP procedure as illustrated in Figure 1 below wasfollowed.

Figure 1 Overview of CP Procedure

PLANNING AND ORGANISATION

As one of the steps in the Cleaner Production Assessment procedure, the objectives of theplanning and organisation phase were to:

obtain management commitment to the project;

set CP project goals;

inform and create understanding from all involved parties;

organise company project team.

SANTREN consultants visited BeefCo several times to obtain management commitmentfor participation in the project. During the first meting, the objectives of the project, the basic principles of CP and possible benefits for the company were explained tomanagement. The General Manager of BeefCo showed great interest and expressed histotal commitment to the project and promised to cooperate.

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Planning and Organisation

Pre assessment

Assessment

Feasibility

Implementation & Continuation


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The discussions with the company resulted in the establishment of a project teamcomprising external consultants and members of staff of BeefCo. There were sevenmembers from BeefCo consisting of the General Manager, Production Supervisor,Electrical and Refrigeration Supervisor, Stores Supervisor, Stock Holder, Accounts Clerkand Audit Assistant while five members were from SANTREN.

The project team was taken through a short training session for one day. The objective ofthe training was to inform and establish a common understanding amongst the teammembers on what Cleaner Production was all about and how it could be applied withinthe company. The contents of the training included: an introduction to CP, anintroduction to waste minimization assessment, CP benefits, assessment team, collectingand compiling data, identifying candidate waste streams, site inspection, evaluation andselection of waste minimization techniques, final report, implementation and evaluation,and conducting periodic reviews and update assessments.

CLEANER PRODUCTION PRE-ASSESSMENT

Before the full assessment, a cleaner production pre-assessment for the plant was carriedout with the aim of setting the plant-wide CP goals, develop process flow charts, evaluatethe general inputs and outputs and selecting an audit focus. This involved walking aroundthe entire processing plant in order to gain a sound understanding of all the processingoperations and their interrelationships. At this stage it was not considered appropriate tolist all the unit processes in fine detail. Instead the plant was broken up into processingareas.

The project team identified four main processing areas: beef processing, pork processing,beef products processing and pork products processing. Besides the four main processingareas, the following processes were also identified: by-products, hides processing, steamsupply system, cooling system, and wastewater treatment. The general flow diagram ofthe plant is shown in Figure 2. The site inspection revealed the following main problems:

High usage of water;

Running hoses;

Uninsulated steam pipes and steam-water mixers; and

Steam leaks.

After observing the problems and evaluating the general inputs and outputs, the projectteam set the following Cleaner Production goals:

to reduce current water consumption and

to reduce current steam energy losses.

By studying the processing operations and asking questions around the plant, it waspossible to identify the areas in the plant where wastewater and energy losses weregenerated. The areas which were selected for cleaner production assessment focus toachieve the goals above were the beef processing, and the steam supply system.

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Final Product (Pork)

FinalProducts

FinalProducts

Final Product(Beef)

Treated Hides

LandfillDisposal

City Sewer

Figure 2General Process Flow Diagram

THE CLEANER PRODUCTION ASSESSMENT

CONSTRUCTING PROCESS FLOW DIAGRAMS

Once the main processing areas which generated wastewater and energy losses had beenidentified, process flow diagrams were constructed for each area. This involved a moredetailed study of each processing area and identification of process inputs and outputs.Figures 3 and 4 show the process flow diagrams for these areas.

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Lairages

Pig

Pig Slaughter &

Dressing Hall

Chiller

Storage

PorkProducts

Processing

SteamGenerator

CoolingSystem

LairageCattle

Cattle Slaughter& Dressing Hall

ChillerStorage

BeefProducts

Processing

GutContentStorage

By-ProductsProcessing

HidesProcessing

Water Treatment


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Live animal

Live animal

Water, Electricity, Wastewater, Spent CartridgesCartridges

Unconscious animal

Water, Electricity Blood,Wastewater,

Cattle headsSlaughtered animal

Water, Wastewater, Hides/skinsSteam Offals, Tail hair, Liver & heart

Fat , Cow heelsDressed animal

Water, Wastewater,

Electricity Reject (to by-products or buried)

Sides (Carcass)

Water,Wastewater

Meat- marking ink

Carcass

Electricity,Water, Wastewater

AmmoniaChilled carcass

Wastewater, SawdustSaw dust

Sliced meat

Figure 3 Beef Processing Flow Chart

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Stunning

Sticking

Bleeding

Dressing

Washing

Splitting

Inspection

Weighing

Grading

Chiller(Storage)

Meat

Processing

Department

Slicing

Dispatch

Lairages


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Water at room temperature ( 24 oC)

Diesel (fuel oil) Heat, Noise, Air emissions(CO2, NOx, SO2)Electricity

City Sewer Water stream

Steam Wasterwater

Hot condensate

Figure 4 Steam Supply Flow Diagram

DEFINING PROCESS INPUTS AND OUTPUTS

The input and output information were collected in the plant simultaneously even thoughthe audit procedures describe these as discrete steps. While conducting the in-plantsurvey and collecting the input and output information, the investigating team noteddown any areas of inefficient operation and any opportunities for waste reduction. Theseopportunities have been described in the Waste Reduction Measures section.

Much of the quantitative data for these flow charts were not available, because of lack ofin-process monitoring. Some of the data used in the assessment were estimates calculatedfrom the aggregated figures basing on the capacity of unit processes and usage whilesome of the data were calculated after taking measurements. The input and outputinformation was therefore recorded as aggregate for processing areas as opposed tospecific units. Ideally, all inputs at each specific unit process were supposed to bedetermined either by direct measuring during the case study or from process monitoring

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SteamGenerator(Boiler)

Cattle Slaughterand Dressing Hall

Pig Slaughter andDressing Hall

By-ProductsCooking

Beef and PorkProductsProcessing

Wastewater Treatment


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records. There were no resources and time available to carry out the direct recording,neither were there any specific records available. The inputs and outputs for the areasunderstudy are shown in flow diagrams in Figures 3 and 4.

CURRENT LEVELS OF WASTE REUSE

Wastewater was not generally reused at the plant except wastewater used in thedefrosting of chillers.

There is however, a high level of reuse of by-products. By-products such as blood, meatproducts unfit for human consumption, bones, offals, meat trimmings and fat areprocessed for animal feed. Fat called tallow is extracted and is used in soap making.

Quantifying Process Outputs

Beef processing outputs were identified (Figure 3). Much of the quantitative data for

these outputs were not available because of lack of in-process monitoring. Some of thedata used in the assessment were estimates calculated from the aggregated figures basingon the capacity of unit processes and usage and measurement of waste masses, volumesand concentrations. Aggregate input and support figures are shown in the figure below.

Input and output figures for beef processing

Cattle (6562 units)

Water 17891.3m3 Cattle Slaughter Water 17953.4m3

Cartridges, (6562) House Hoofs 26248 unitsElectricity, Heads 6562 unitsSteam 993.6Mt Internal organs (93.9-156.4Mt)

Beef 972.14Mt

Accounting for wastewater flows and concentrations.

All wastewater streams were identified and sampled. The investigation was performedduring the period between January to August 1999 in order to cover a full range ofoperating conditions. Most of the wastewater from unit processes is drained into the CityAssembly sewer system after wastewater treatment process. Figure 2 outlines thewastewater streams. The study highlighted areas where water consumption could bereduced.

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Documenting waste stored or hauled off site for disposal.

Solid waste stored or hauled off site for disposal included

grass bedding (not quantified)

manure trimmings (washed during cleaning).

undigested foods from throat (not quantified)

Solid waste sold

heads (6562/year)

hoofs (26248/year)

hides (6562/year) - exported

MATERIAL BALANCE

Assembling unit process input and output information

The material balance study was done by first assembling complete input and output dataas given in unit process flow charts i.e. the receiving area, stunning, sticking andbleeding, flaying, evisceration and splitting and chilling and dispatch.

Preliminary Material balances.

Receiving area

Company trucks bring the cattle to the receiving area. After unloading the cattle in the

receiving area, trucks are cleaned and disinfected while the cattle are inspected. Thecattle are kept for about 12 hours before slaughter. They are not fed but are given a lot ofwater.

Process Figure

Live cattle

Receiving vehicle Manure

Water cleaning inspection wastewaterDisinfectant Grass beddingGrass bedding

Live cattle

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Material Balance

Inputs Outputs

Live cattle: 6562 unitsWater: (not quantified)Grass bedding: not quantified

Live cattle: 6562 unitsWastewater: not quantifiedGrass bedding: not quantifies

STUNNING, STICKING & BLEEDING

Live cattle are led into the stunning box using an electricity charged rod called prodder.Some water is splashed over the cattle to make electric shock more effective. The cattleis then stunned by gunstroke in the head.

The unconscious cattle is hoisted and dragged into a rectangular enclosure with concrete

walls about 30 cm high adjacent to the stunning box. Then it is killed by cutting the throatwith a steam-sterilized knife. The cattle is left to bleed for approximately ten minutes.

Process Figure

Cattle

Water StunningCatridges Sticking Blood, Head, WastewaterSteam Bleeding Undigested foods.

Carcass (Dead cattle)

Material Balance

Inputs Outputs

Unconscious cattle: 6562 units, not

weighed before slaughterWater: not quantifiedSteam: not quantifiedCatridges: 6562 units

Dead cattle: 6562 units

Wastewater: not quantifiedBlood: approx. 98430 litresHeads: 6562 unitsUndigested foods from throat: not

quantified

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FLAYING (DRESSING), EVISCERATION AND SPLITTING

Using a rail hoist the bled cattle is taken to a dressing table where the carcass is flayedand its internal organs removed. Four to five people are used to flay one carcass, aprocess that takes 3 to 5 minutes.

The objective of flaying is to remove the skin and gain access to the internal organs inorder to remove them, a process called evisceration. Access to the internal organs isachieved by opening the abdomen with a knife.

Steam is used for sterilizing knives and heating water for cleaning hoofs.

Afterwards, the carcass is split into two halves using an electric saw and then inspectedby an official from the Department of Veterinary Services. Thereafter it is graded andweighed.

Process Figure

Carcass

Flaying Blood, internal organsSteam, Evisceration (intestines, liver etc), hide,Water, Splitting trimmings, hoofs, steamElectricity wastewater.

Flayed, Eviscerated and Split Carcass

Material Balance

Inputs Outputs

Carcasses: 6562 units, not weighed before

splittingSteam: not quantifiedElectricity

Half split carcasses:972.14Mt

Wastewater: not quantifiedBlood: not quantified and negligibleInternal organs: 93.9 - 156.4 MtTrimmings: not quantifiedHides: 6562 unitsHoofs: 26248 units.

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CHILLING AND DISPATCH

After weighing and grading the carcasses are chilled for a least 12 hours in a chiller set at2C. Thereafter they are dispatched either to Sales Department or Processing Department

or further stored at -12C.

Water is used to clean and defrost the chiller. The wastewater goes into the reservoir forreuse and some goes into the sewer when the reservoir overflows.

Process Figure

Half split carcasses

Water Chilling WastewaterElectricity Dispatching Ammonia (leaks)Ammonia

Chilled half split carcasses

Material Balance

Inputs OutputsBeef 972.14MtWater, not quantifiedAmmonia, not quantifiedElectricity not quantified

Chilled beef - approximately 972.14MtWastewater - not quantifiedAmmonia due to leaks (not quantified)

STEAM SUPPLY SYSTEM

Another area that was studied was the steam supply system.

The steam supply system is used to provide steam for boiling, heating and sterilisation.

Quantifying Process Outputs

The steam is produced in a boiler and transferred through pipes to machines andsteam/water mixers. The boiler uses diesel fuel and on average it consumes 47,800 litresper annum. Water at ambient temperature is fed and from calculations using the boiler

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capacity and the period the boiler is run, the amount of water used was found to beapproximately 248,400 litres per annum.

Process FigureWater (at room temp. 24C)

Diesel (fuel oil) Noise and HeatAir emissions

Electricity (C02, N0x, S02)

Steam

Material Balance

Inputs Outputs

Diesel (0.51% sulfur) 40,646kg

(47,800 litres)

Water (at ambient temp)248,400 litres

Energy content 1866.27 GJ

Carbon dioxide (C02 ), not quantifiedNitrogen oxides (N0x ), not quantifiedSulfur dioxide (S02), not quantifiedSteam 374,000 kg

1 kg of oil = 1.176 litres of oil (0.85 kg/I ) 1 kWh = 3.6MJ (BP Southern

Africa Typical Characteristics, 1999)

ACCOUNTING FOR WASTEWATER AND ENERGY LOSSES

During the study it was discovered that no condensate was returned to the boiler

for re-heating. In the cattle and pig slaughterhouses, steam was directly used inheating water in steam/water mixers and was eventually discharged into the sewersystem. All the steam except that lost due to leaks turned back into water anddischarged into the wastewater treatment plant and the nearby stream.

Some of the pipes were not insulated. A total of approximately 80m and 100m of50mm diameter and 25mm diameter pipes respectively were not insulated. Thesurface temperatures of the pipes and the temperature of the steam at source weremeasured in order to calculate the heat energy losses. The rate of condensate flowand its temperature were also measured to determine the heat energy lossesthrough the condensate. Steam leakage points were also noted. A total number of

eight steam leakage points were noticed.

Insulation of steam pipes and other hot surfaces.

About 80m of 50mm diameter pipe to the by-products and about 100m of 25mmdiameter pipe to the pig and cattle slaughter houses and the kitchen were notinsulated. Assuming an average of 3 hours and 276 days of steam running thetotal energy loss through natural convention is a bout 72.68 GJ an equivalent of1816.53 litres of diesel oil. In other words about 1816.53 litres of diesel was lost

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Steam supply

(Boiler)


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through energy loss in uninsulated pipes (sample calculations are shown inAppendix B).The steam/water tank mixer in cattle slaughterhouses was not insulated. The totalsurface area of the tank was 6.283m2. Energy loss due to evaporation and naturalconvection was approximately 27.15GJ per annum, an equivalent of 695.38 litres

of diesel oil.

Utilization of condensate

The condensate was not returned to the boiler. The condensate was discharged at

about 100C at a rate of about 6 litres/minute. This means that both energy andwater were wasted. Energy loss through 1000 litres of lost condensate represents

8.7 kg of diesel oil at a condensate temperature of 100C. An estimate of 248,400litres of condensate per annum was an equivalent of 3253.8 kg of diesel or 3774.4litres of diesel lost. There was also a total loss of about 374,000 litres (374 m 3 ) ofwater.

ENVIRONMENTAL AND ECONOMIC CONCERNS

The following environmental and economic concerns were observed during theassessments in the unit processing areas.

Receiving Area Koala

A considerable amount of manure was produced in this area. If this is not properlywashed down into the sewer, it may drain into the adjacent public water course and hencelead to water pollution.

Stunning, sticking and Bleeding

Wastewater

Most of the blood went straight into the blood tank awaiting processing into blood meal.In most cases the water used to clean the bleeding area went into the blood tank. Thisincreased the time and heat energy required to evapolate the water during blood cooking.Some of the wastewater containing blood as a result of cleaning the floor went straightinto the sewer.

Water wastage

A lot of water was used in cleaning the sticking and bleeding area and also washing

hands and equipment such as knives.

Energy wastage

Since sterilization was done using steam, a lot of energy was used in generating the steam the boiler was usually on for at least two hours everyday. A lot of steam was lost duringsterilization due to indiscriminate opening of the steam valve.

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Flaying, Evisceration and Splitting

Energy and water wastage

Sterilization of knives was done using steam and as a result a lot of heat was lost. Therewas also high water consumption during cleaning of hoofs, carcasses, offals and the floorarea.

Wastewater

Trimmings that were washed during cleaning of the floor found their way into the sewersystem resulting in high BOD.

Chilling and Despatch

Energy wastage

The chillers were under-utilized resulting in high usage of energy.

Ammonia leakage

The recharging of refrigeration plant with ammonia indicated that ammonia leaked intothe atmosphere.

WASTE REDUCTION MEASURES (CP OPTIONS)

From the information accumulated from the waste audit and observations that were madewhile investigating the plant in detail, a number of waste reduction and efficiencyimproving measures, were identified. These are split into four unit processing areas in

beef processing, wastewater treatment plant and the steam supply steam.

(a) Receiving area Koala

From the studies at the receiving area, it was noted that water consumption needed to bechecked. Use of hosepipes with pressure controlled spray guns would reduce the waterusage considerably.

(b) Stunning, Sticking and Bleeding

A lot of water was used in cleaning the sticking and bleeding area, and also washing

hands and equipment such as knives. Water usage in this area could have been minimizedthrough good housekeeping to ensure that taps were not left open longer than wasnecessary. Cleaning of the area could have been effected through use of hose pipes with pressure controlled spray guns. In addition, the bleeding area should have beenconstructed in such a way that the blood collected into some container in the form of atrough rather than splashing in a wide area which would have had to be cleaned usinglarge amounts of water.

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Energy wastage was observed through the steam that was lost during sterilization due tothe indiscriminate opening of the steam valve. Good housekeeping measures could havereduced this wastage. In addition, sterilization of knives and other equipment shouldhave been carried out using standard sterilization equipment.

Blood needed to be separated from other wastes such as water in order to get qualityblood for the blood meal and to reduce energy requirements and time during the cookingof blood.

(c) Flaying, Evisceration and Splitting

Sterilization of knives in the flaying, evisceration and splitting area was done usingsteam, and as a result, a lot of heat was lost. There was also high water consumptionduring cleaning of hoofs, carcasses, offals and the floor area.

Sterilization of knives and other equipment should have been carried out using standard

sterilization equipment.

To reduce energy wastage it was important that the steam/water mixer tank be coveredwith a lid and insulated.

Usage of water during cleaning of the floors could have been greatly reduced byremoving blood, trimmings and other remains using rubber brushes.

Every drain should have had a strainer to enable removal of bigger particles.

(d) Chilling and Dispatch

When production was low some coldrooms should have been switched off, and allcarcasses kept in one coldroom irrespective of ownership. This could have beenfacilitated by improving on identification and security system. The central cooling systemcould have been replaced with unitary cooling systems to allow shutdown of somecoldrooms when not needed.

All leaks should be attended to on routine basis.

(e) Wastewater Treatment system

Most of the blood from sticking and bleeding went straight into the blood bank awaitingprocessing into blood meal. In most cases the water used to clean the bleeding area wentinto the blood tank. This increased the time and heat energy required to evaporate thewater during blood cooking. Some of the wastewater containing blood as a result ofcleaning the floor went straight into the sewer.

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Trimmings that were washed during cleaning of the floor in the flaying and splittingfound their way into the sewer system resulting in high BOD loadings on the wastewatertreatment plant.

The wastewater treatment plant received the bulk of the wastewater generated at the site,

including WC flushings and sludge.

Wastewater treatment at the site consisted of the following stages: - screening, gritremoval, primary sedimentation, biological treatment, and secondary sedimentation.

All unit processes for wastewater treatment plant operated satisfactorily except the bio-filtration process where the arms did not rotate. It was recommended that these beattended to in order to facilitate the efficient operation of the plant, particularly withrespect to biological treatment of the wastewater.

The effluent had high levels of BOD5. Between January to August 1999, the average

recorded BOD5 was 603mg/l. This was higher than the recommended limit of 400mg/l(City Assembly). The fatty matter (oils) in the effluent was also very high. The averagevalue during this period was 1744mg/l against the recommended limit of 200mg/l. (CityAssembly).With the biofiltration plant not functioning normally (the rotor arms did not rotate) thewastewater treatment plant was unlikely to perform at its optimum.

The payment of discharge penalties due to high levels of BOD5 was clear evidence ofsub-optimal performance of the plant.

Although the wastewater treatment plant was an end-of-pipe technology, its optimal performance was important in reducing the level of BOD5 in the effluent. If thebiofiltration process were made to operate normally, the BOD5 in the wastewater wouldhave been greatly reduced.Discharge penalties through violation of discharge standards would have been avoidedthereby reducing operation costs.

(f) Steam Supply System

Oil handling

It is very important to avoid oil spills, and if they occur, they need to be cleaned upproperly. Oil spilling can cause serious pollution of soil and water. One litre of oilcontaminates 100,000m3 of water, rendering it unfit for drinking (UNEP, 1999).

Steam leakage

Steam leaks should be repaired as soon as possible when identified.

Insulation of hot surfaces

Insulation of hot surfaces is a cheap and very effective way of reducing energyconsumption.

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Through proper insulation of hot surfaces (pipes) the heat losses will be reduced by 90%.Often the payback period for insulation is less than 3 years.

Utilization of condensate

Heat exchanger pipes in the steam/water mixers in the pig and cattle slaughterhousesshould be used. Steam condensate from the heater exchangers and by-products machineshould be returned to the boiler. The payback period for such a system would be shortconsidering that 1m3 of lost condensate represents 8.7kg of oil at a condensate

temperature of 100C. There is also some saving in water consumption.

Proper operation of the boiler

The efficiency of boiler depends on how well the boilers are operated. If the air/fuel ratiois wrongly adjusted the incineration will be poor, causing more pollution and/or poorerutilization of the fuel. Proper operation of the boiler requires proper training ofemployees.

PRELIMINARY EVALUATION ON CP OPTIONS

The objective of this step was to select and prioritise the cleaner production options forfurther study.

A satisfactory number of waste reduction options were generated. The options werescreened and priotised on the basis of availability, suitability, environmental effect andeconomic feasibility using the checklists for availability, suitability, environmental effectand economic feasibility given in Appendix A. The obvious no and low cost options wererecommended for implementation without carrying out feasibility studies. Some of the

obvious no and low cost options which required simple feasibility studies have beenpresented in the proceeding sections.

A further extensive feasibility study was recommended for the wastewater treatmentplant.

FEASIBILITY STUDIES

COST/BENEFIT ANALYSIS

Following the preliminary evaluation, the following CP options were identified for

simple feasibility studies.

(a) Water consumption in cattle slaughterhouse

Since automatic on-off water valves were not readily available, a simple design of controlvalve using Conventional Gate Value could have been used.

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This arrangement would involve connecting a galvanized pipe 25mm, 0.5m long to ahosepipe and the gate valve and another small piece of galvanized pipe 25m long with anozzle. The user would hold the galvanized pipe piece to open or close the valve. Theuser would not have to travel a distance to open or close the valve, as was the case.

Therefore free running of water would have been reduced. Water would come out of thenozzle at a higher pressure and this would have facilitated the cleaning operation,reducing the water usage even further. The cost of installing such a system for 17-wateroutlet points was US$110.00.

Subject to verification, it was assumed that this system should have been able to reducewater consumption in the cattle slaughterhouse by 50%.

Cattle slaughterhouse

Total number of cattle slaughtered 562

Total water consumption 17,891m3

Number of water outlets 14Total cost of installing new valves US$92.00

Current average water consumption 2859 litres/cattle

Equivalent cost US$2.6

50% reduction in water consumption 1430 litres/cattle

Equivalent cost US$1.3

Savings US$1.3

Number of animals to pay back the cost ofinstallation

68 cattle

Total savings assuming the same number of animalswere slaughtered/year

US$8252.00

After slaughtering 68 cattle and 46 pigs, the cost of installation would be covered.

(b) Energy conservation Steam Pipe Insulation

Insulation of steam pipes with fiberglass material was considered. At the time of thestudy the total length of uninsulated steam pipes was 180m (i.e. 80m of 50mm diameterand 100m of 25mm diameter pipes).

Cost of insulating 100m x 25mm US$1004.00

Cost of insulating 80m x 50mm US$1444.32Total cost of insulating material US$2448.34

Labour cost (32 man hours) US$23.18Total cost US$2471.52

(With reference to Appendix B)

Current loss of energy due to uninsulated pipes only is 72.68 GJEquivalent of diesel 1816.53 litresEquivalent cost of diesel US$1070.00

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Assuming the constant saving of US$1070/year was cash inflow and interest charge(discount) rate on capital is 36% (current bank savings rate), the Net Present Value wouldbe as follows:-

Year Cash Flow Present Value of Income Expenditure lessincome (US$)Out (US$) In (US$)

0 2471.52 -

1 1070.00 786.76 1684.76

2 1070.00 578.50 1106.26

3 1070.00 425.37 680.89

4 1070.00 312.77 368.12

5 1070.00 230.00 138.12

6 1070.00 169.10 -30.98

The Net Present Value of a six years period was US$30.98. The cost of the project toinsulate the steam pipes would be covered after five years. This period could be muchlower if the increase in cost of fuel over this period was taken into consideration.

(c) Condensate Utilization

Utilization the condensate would have involved installing a system to collect thecondensate and return it to the boiler for reuse. The materials required included a plastictank, pump and motor, heat exchange pipes, drain pipe, return pipe, valves and T-junctions.

Total material cost US$1755.00Installation cost (labour) US$82.00Running cost (for one year) US$95.00Total cost US$1932.00

(With reference to Appendix B)

Savings for reuse of 248400 litres of condensate(or 2506.85 litres of diesel equivalent) US$1476.25

Savings from reuse of water 374m3 US$335.55Total savings/year US$1811.80

Pay back period 1year and 1 month

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APPENDICES

APPENDIX A

CHECKLIST FOR OPTIONS FEASIBILITY STUDY

Availability

Is the cleaner production optionavailable

Can you find a supplier who cansupply you with the necessaryequipment or input material

Do you know an advisor who canhelp you develop an alternative?

Has the cleaner production optionalready been applied elsewhere?

If so, what are the results andexperiences.

Suitability

Does the option fit in with the wayyour company is run?

Is the option in line with yourcompany's product?

What are the consequences of theoptions for your internal logistics,throughout time and production

planning Does the option require adjustments

in other parts of the company?

If so, what adjustments?

Does the change require additionaltraining of staff and employees?

Environmental Effect

What is the anticipated environmentaleffect of the option?

How big is the estimated reduction in

the waste stream or emission? Will the option affect public or

worker health?

If so, what is the magnitude of theseeffects in terms of toxicity andquantity (positive/negative)

Economic Feasibility

What are the anticipated costs andbenefits from implementing theoption?

Can you estimate the requiredinvestment

Can you make an estimate of thebenefits, such as reduction ofenvironmental costs, reduction inwastage and/ or improving the qualityof the product?

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APPENDIX B

SAMPLE CALCULATION ON HEAT LOSS FROM UN-LAGGED PIPE

Natural Convection

Pipe Surface Temperature = 116C

Room Temperature = 28CFor horizontal pipes, Nu = 0.527(Pr) (Pr + 0.952) (Gr)

Coefficient of cubical expansion, = 1 = 1 = 1 .T 28 + 273 301K

At T = 389K (16 + 273) Pr 0.69

Gr = g d3V2

From Table v = 2.454 x 10-5 m2/sGr = 1 x 9.81 x (116 28) x (0.0605)3 = 10.55 x 105

301 (2.454 x 10-5)2

substituting Nu = 0.527 (0.69) (0.69 + 0.952) (10.55 x 105)= 23.88

Nu = hd = 23.88K

Heat transfer coefficient h = 23.88 x 3.276 x 10

-5

k for air at 3890.0605= 0.0129 kW/m2K

heat loss per metre length Q = hA(tw t)

= 0.0129 x 103 x x 0.0605 x 1 (116 28)= 215.76W

Total loss = 17.26 kW

For 80m length of un-lagged pipeAssuming 3 hrs of running/day for 276 days in a year

3 x 60 x 60 x 276 = 2.98 Mega sec.Energy loss = 2.98 x 106 x 17.26 x 103

= 51.44 GJEnergy loss from a 33mm diameter pipe = 21.34GJ

Therefore total energy loss from un-lagged pips = 72.86 GJFrom the calorific value of diesel 45.29 MJ/kgEnergy equivalent of diesel oil = 1604kg of diesel x 1.17

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= 1861.53 litres of diesel

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cp case manual[1]

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