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Chemical treatment of poultry abattoir wastewater.

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Presentation on theme: "Chemical treatment of poultry abattoir wastewater."— Presentation transcript:

1 Chemical treatment of poultry abattoir wastewater

2 Contents of Presentation Introduction Introduction Aims & Objectives Aims & Objectives Methodology Methodology Results & Discussion Results & Discussion Conclusions & Recommendations Conclusions & Recommendations

3 Introduction 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

4 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

5 Parameter Maximum permissible concentration Chemical Oxygen Demand1500 mg/l Chloride (as Cl - ) and sulphate as SO 4 2- combined 1500 mg/l pH5 - 9 Total suspended solids400 mg/l Oil & grease150 mg/l Discharge 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

6 Abattoir 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

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

8 Methodology 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

9 2. Characterization of Wastewater Streams Poultry Abattoir Sewer Map showing sampling locations

10 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

11 Preservation of Samples ParameterContainerPreservation Maximum Holding Time ChlorideP,GNone required28 days NitrateP,GCool, 4 o C48 hours Oil and greaseG Cool, 4 o C H 2 SO 4 to pH < 2 28 days TSSP,GCool, 4 o C7 days BODP,GCool, 4 o C48 hours CODP,G Cool, 4 o C H 2 SO 4 to pH < 2 28 days Hydrogen ion (pH) P,GNone required Analyze immediately TurbidityP,GCool, 4 o C7 days

12 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.

13 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 (FeCl 3 ), Sodium Hexamethaphosphate (HMP), Alum, Primco 730 and Primco 738 and flocculent used was Nalco 9617

14 Collection of wastewater sample at effluent treatment plant Carrying out of Jar test Experiments Each time a coagulant was used the optimum dosage was determined by the turbidity test

15 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

16 Results & Discussion 1. 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

17 2. Effluent streams characterization results pH COD (mg/l) Oil & grease (mg/l) TSS (mg/l) Chloride (mg/l) Sampling location RangemeanRangemeanRangemeanRangemeanRangemean Killing section (S2) Evisceration section (S8) Spin chilling section (S11) Live dock section (S12) 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

18 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

19 ParameterPollution range Mean pollution load Discharge limit pH6.51 – – 9 COD (mg/l)3885 – Oil & grease (mg/l) 44.3 – TSS (mg/l)605 – Chloride67.5 – Result of the characterization of the final effluent 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

20 3. Jar Tests Results Combinations of Coagulants and Nalco 9617 Turbidity (FTU) 225 ppm FeCl ppm Nalco ppm HMP + FeCl 3 (1:1) mixture + 15 ppm Nalco ppm HMP + 15 ppm Nalco ppm Alum + 10 ppm Nalco Combinations of coagulants and Nalco 9617 dosages giving lowest turbidity Lowest turbidity with combination of 225 ppm FeCl 3 & 10 ppm Nalco 9617 The combination of 325 ppm of alum + 10 ppm Nalco 9617 gave the highest turbidity

21 Coagulants Best working pH range Resulting turbidity range (FTU) FeCl – – 79 HMP + FeCl 3 (1:1)3.3 – – 28 HMP3.5 – – 65 Alum6.0 – – 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 FeCl 3 + HMP gave appreciable turbidity results at a low pH range

22 Comparison of Efficiency of combinations coagulants & Nalco 9617 The combination of HMP & Nalco 9617 removed the highest percentage of COD from the wastewater The combination of FeCl 3 & Nalco 9617 removed the highest percentage of turbidity and TSS

23 Cost of effluent treatment per m 3 Combinations of chemicals Cost of treatment (Rs/m 3 ) FeCl 3 + Nalco HCl % FeCl % HMP + Nalco HCl HMP + Nalco HCl27.30 Alum + Nalco HCl16.55 Least cost is obtained by treating the effluent with a combination of FeCl 3 + Nalco 9617 Highest cost is obtained by treating the effluent with chemical combinations containing HMP

24 Raw effluent Effluent treated with HMP Effluent treated with FeCl 3 Effluent when treated with alum

25 Conclusion & Recommendations Conclusions : 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 FeCl 3 + Nalco 9617 removed the highest percentage of turbidity & TSS Treating the effluent with combinations containing HMP would be more expensive

26 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 m 3 /day. This 96 m 3 of effluent can be directly sent to the sewer network or use to rinse the blood in the blood trough during the neck severing process Further research : Determining the best disposal option for the 96 m 3 of effluent which completely conforms with the discharge regulations

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