ByBy

Fabrice Pellegrin & A.K. Ragen Fabrice Pellegrin & A.K. Ragen

Chemical treatment of poultry abattoir Chemical treatment of poultry abattoir wastewaterwastewater

Contents of Contents of PresentationPresentation

Introduction Introduction Aims & ObjectivesAims & Objectives MethodologyMethodology Results & DiscussionResults & Discussion Conclusions & RecommendationsConclusions & Recommendations

IntroductionIntroduction From the year 2000 to 2006 the poultry production in Mauritius had increased by 40.6 % Two major slaughterhouses in Mauritius operating on an industrial scale One of these abattoirs processes about 30,000 birds per day Poultry slaughterhouses make use of significant quantity of high quality water for their operations

About 88 % of the water intake is directly converted into wastewater with a strong organic content The strong organic wastewater generated contains high levels of oil & grease, total suspended solids (TSS) and nutrients With the introduction of norms on limiting wastewater discharge, it is now a legal requirement for poultry slaughterhouses in Mauritius to treat their wastewater to such quality to meet discharge norms

Parameter Maximum permissible

concentration

Chemical Oxygen Demand 1500 mg/l

Chloride (as Cl-) and

sulphate

as SO42- combined

1500 mg/l

pH 5 - 9

Total suspended solids 400 mg/l

Oil & grease 150 mg/l

Discharge parameters to be complied with by poultry abattoirsDischarge parameters to be complied with by poultry abattoirs

The abattoir under study is equipped with a Dissolved Air Floatation System (DAF) as means of treatment to remove pollution from the wastewater

Abattoir ProcessesAbattoir Processes

Stunning: process whereby birds are made insensible before slaughtering Neck severing Scalding: wetting & partially removing the birds feathers Plucking Evisceration: the purpose of evisceration is to remove all the thoracic & abdominal organs and separating the edible viscera from the inedible ones Spin chilling: to chill & disinfect the carcasses before packaging

Aims & ObjectivesAims & Objectives To determine the specific water intake (SWI) of the To determine the specific water intake (SWI) of the abattoirabattoir To characterize the outgoing wastewater streams in To characterize the outgoing wastewater streams in terms of COD, pH, chloride, TSS and oil & grease terms of COD, pH, chloride, TSS and oil & grease To carry out standard jar tests to determine the To carry out standard jar tests to determine the optimum conditions of various chemicals on the optimum conditions of various chemicals on the wastewaterwastewater To find a proper way to dispose of the blood generated To find a proper way to dispose of the blood generated by the slaughtering of chickenby the slaughtering of chicken

MethodologyMethodology

1. Determination of Specific Water Intake (SWI)

The SWI was determined by: taking the readings of the CWA flowmeter connected on the supply line to the abattoir on each working day for a period of one month Recording the amount of birds processed on each working day over the same period

2. Characterization of Wastewater StreamsPoultry Abattoir Sewer Map showing sampling locations

Sampling of wastewater streams

13 composite samples were taken each day for 5 days (In all 65 samples were taken) Composite sampling was chosen to

eliminate possible errors that might have occurred due to:

1. An irregular flow of birds on the line shackles 2. An irregular water flow inside the abattoir

Preservation of Samples

Parameter Container Preservation Maximum

Holding Time

Chloride P,G None required 28 days

Nitrate P,G Cool, 4oC 48 hours

Oil and grease G Cool, 4oC

H2SO4 to pH < 2

28 days

TSS P,G Cool, 4oC 7 days

BOD P,G Cool, 4oC 48 hours

COD P,G Cool, 4oC

H2SO4 to pH < 2

28 days

Hydrogen ion

(pH)

P,G None required Analyze

immediately

Turbidity P,G Cool, 4oC 7 days

Methods of Analysis

Chloride was determined using the Mohr`s method as per the ISO 9297:1989(E) standard All the other parameters were analyzed by means of the US-EPA approved Hach DR/2000 spectrophotometer.

3. Jar Test Experiments

The wastewater samples for jar tests were taken on 5 days (each day 25 L of grab sample was collected) Grab sampling was chosen because composite sampling might have obscured some important parameters such as turbidity and pH The jar tests were carried as per the ASTM D 2035 – 80 (2003) method Coagulants used were Ferric chloride (FeCl3), Sodium Hexamethaphosphate (HMP), Alum, Primco 730 and Primco 738 and flocculent used was Nalco 9617

Collection of wastewater sample at effluent treatment plantCarrying out of Jar test Experiments

Each time a coagulant was used the optimum dosage was determined by the turbidity test

The tests were repeated by placing the same optimum coagulant dosage in each beaker but that time the pH of the wastewater was varied (different pH in each beaker) Most of the time, when the optimum coagulant dosage was determined (with or without change in pH), the tests were repeated by placing the same optimum coagulant dosage in each beaker and different doses of Nalco 9617 (flocculent) were added to the beakers

Results & Discussion1. SWI results

Variations in SWI per bird over a period of one month

The SWI varied from 14.3 to 28.4 L/bird The figure illustrates 4 peaks in the SWI at 28.4, 25.6, 22.3 & 24.8 L/bird These peaks may be explained by the fact that on those days fewer birds were processed but the same amount of water was used The average SWI = 17.9 L/bird

2. Effluent streams characterization resultspH COD

(mg/l)

Oil & grease

(mg/l)

TSS

(mg/l)

Chloride

(mg/l)

Sampling

location

Range mean Range mean Range mean Range mean Range mean

Killing

section (S2)

6.45 -

6.65

6.47 5230 -

6260

5840 536 -

604

575 1745 -

2325

2099 165.1-

195.3

179.5

Evisceration

section (S8)

6.70 -

6.85

6.77 3870-

4425

4205 302-

474

414 664-

745

705 72.7-

104.9

86.4

Spin chilling

section (S11)

7.74-

7.87

7.79 3425-

4330

3905 28.3-

43.0

36.8 515-

685

593 137.2-

156

148

Live dock

section (S12)

9.30-

9.47

9.38 2420-

3440

3075 12.3-

21

16.8 196-

237

220 72.8-

99.5

87.2

The pollution load in some streams varied quite widely The cause of such variations was probably due to an irregular flow of birds on the line shackles at some time when the wastewater samples were taken

The COD load from 4 streams in the evisceration section complied with the discharge norms 1 Stream from the killing section and 2 streams from the evisceration section did not comply with the discharge norms in terms of oil and grease The TSS load from 4 streams in the evisceration section complied with the discharge regulations 4 Streams were not polluted these were the outlet from the vent opener (S3), neck cracker (S5), inside outside washer (S7) & spin washer 2 (S10)

Summary of characterization results from the different sections

Parameter Pollution range

Mean pollution

load

Discharge limit

pH 6.51 – 6.72 6.63 5 – 9

COD (mg/l) 3885 – 4685 4230 1500

Oil & grease (mg/l)

44.3 – 163.2 57.2 150

TSS (mg/l) 605 – 930 789 400

Chloride 67.5 – 92.3 76.8 1500

Result of the characterization of the final Result of the characterization of the final effluenteffluent

The highest value for oil & grease occurred because on one sampling day the rotary screen at the treatment station was not working The TSS and the COD loads did not comply with the discharge norms

3. Jar Tests ResultsCombinations of Coagulants and

Nalco 9617

Turbidity (FTU)

225 ppm FeCl3 + 10 ppm Nalco 9617 29

175 ppm HMP + FeCl3 (1:1) mixture +

15 ppm Nalco 9617

23

175 ppm HMP + 15 ppm Nalco 9617 40

325 ppm Alum + 10 ppm Nalco 9617 62

Combinations of coagulants and Nalco 9617 dosages giving lowest turbidity

Lowest turbidity with combination of 225 ppm FeCl3 & 10 ppm Nalco 9617 The combination of 325 ppm of alum + 10 ppm Nalco 9617 gave the highest turbidity

Coagulants Best working

pH range

Resulting turbidity

range

(FTU)

FeCl35.3 – 6.0 38 – 79

HMP + FeCl3 (1:1) 3.3 – 4.3 21 – 28

HMP 3.5 – 4.5 18 – 65

Alum 6.0 – 8.0 40 – 82

Comparison of the efficiency of chemicals on the effluent in terms of pH

Alum gave better results at a higher pH range than the other coagulants and the mixture of FeCl3 + HMP gave appreciable turbidity results at a low pH range

Comparison of Efficiency of combinations coagulants & Nalco 9617

05

10152025

303540

455055

606570

75808590

95100

% p

oll

uta

nt

rem

ova

l

% CODremoval

% TSSremoval

%Turbidityremoval

% COD removal 75.3 80.1 87.7 65.1

% TSS removal 98.8 96.9 98.1 97.2

%Turbidity removal 97.5 95.8 97.1 92

FeCl3FeCl3 +

HMPHMP Alum

The combination of HMP & Nalco 9617 removed the highest percentage of COD from the wastewater The combination of FeCl3 & Nalco 9617 removed the highest percentage of turbidity and TSS

Cost of effluent treatment per m3

Combinations of chemicals Cost of treatment

(Rs/m3)

FeCl3 + Nalco 9617 + HCl 14.48

50 % FeCl3 + 50 % HMP + Nalco

9617 + HCl

26.43

HMP + Nalco 9617 + HCl 27.30

Alum + Nalco 9617 + HCl 16.55

Least cost is obtained by treating the effluent with a combination of FeCl3 + Nalco 9617 Highest cost is obtained by treating the effluent with chemical combinations containing HMP

Raw effluent Effluent treated with HMP

Effluent treated with FeCl3 Effluent when treated with alum

Conclusion & RecommendationsConclusions:

The SWI was found to be 17.9 L/bird Wastewater streams S3, S5, S7 & S10 completely complied with the discharge regulations The combination of HMP + Nalco 9617 removed the highest percentage of COD whereas the combination of FeCl3 + Nalco 9617 removed the highest percentage of turbidity & TSS Treating the effluent with combinations containing HMP would be more expensive

Recommendations: All hoses should be fitted with self-closing nozzles to eliminate wastage when not in use The effluents from streams which completely conforms with the discharge regulations amounts to 96 m3/day. This 96 m3 of effluent can be directly sent to the sewer network or use to rinse the blood in the blood trough during the neck severing processFurther research: Determining the best disposal option for the 96 m3 of effluent which completely conforms with the discharge regulations