Mwangi Simon Thuku F21/2492/2009 Supervisors : Mr. Orodi Odhiambo

1. UNIVERSITY OF NAIROBI ENVIRONMENTAL & BIOSYSTEMS ENGINEERING Design of a biological slaughterhouse wastewater treatment system (Using an anaerobic baffle reactor – constructed wetland system) < case study of Kiserian Slaughterhouse> Mwangi Simon Thuku F21/2492/2009 Supervisors : Mr. Orodi Odhiambo Eng. D. A. Mutuli

2. BACKGROUND Approximated slaughterhouse waste content and NEMA standards for disposal into the environment Johns et al., 1995; Manjunath et al., 2000, NEMA

3. BACKGROUNDCont’d Treatment Options • Anaerobic treatment + activated sludge • Anaerobic treatment + contact aeration • Activated sludge + chemical coagulation • Contact aeration + chemical coagulation.

4. Problem Statement • This waste water flows to R. Kiserian and eventually gets to Kiserian Dam. • This causes eutrophication and anoxia in the water bodies. • Waste from slaughterhouses also leads to air and soil pollution Pre- treated Wastewater getting into the streams

5. Site Analysis • Kiserian is a settlement in Kajiado county • Habitants are mainly pastoralist community • Warm and Temperate climate. • Rainfall =833mm • Temperature = 17.8

6. Objectives Overall objective To design a biological slaughterhouse wastewater treatment systemSpecific Objectives To analyze the amount and the content of wastewater To establish pertinent parameters for design of a biological slaughterhouse waste water treatment system. To use the parameters from (ii) to size the baffle reactor and the constructed wetland.

7. Statement of the scope • Survey work • Carrying out tests • Determination of System Design Parameters • Making detailed engineering drawings Literature review • Treatment Process ( primary, secondary and tertiary treatment) • Why anaerobic? • Anaerobic Baffle reactor (improved septic tank) • Constructed Wetland

8. Methodology Survey Soil and waste water sampling Laboratory tests (soil & waste water) Determining the efficiency of ABR ABR volume determination Result analysis Designing the wetland Structural design of the ABR

9. Theoretical Framework Chemical oxygen demand, Biochemical Oxygen Demand, BOD5,mg/L = Sasse (1998), Wanasen (2003), Foxon et al., (2004) etc

10. Results

11. Results Cont’d Leslie C.P. et al, 1999

12. Results Cont’d Qi = 14.5m3/d y = 0.7 m As = 126.22 m2 t = 1.85 days width = 7.94 m dh = 0.01 x 15 = 0.15m Length = 2 x 9 = 16 m slope is taken to be 1.5

13. Drawings

14. Drawings

15. Drawings

16. Drawings

17. Drawings

18. Conclusion • Objectives of the design project were met. • slaughterhouse wastewater was observed to have high content of waste. • The BOD5 removal efficiency for the ABR was found to be 90% (i.e. from 936.25mg/l to 93.625mg/l) with a HRT of 2.38days. The organic lading in the ABR was found to be 1.314 kg COD/m3.d (should range between 1 – 3 kg COD/m3.d). • The CW reduced the concentration of nitrates in the waste water from 141.5 mg/l to 100 mg/l and the BOD from 93.625mg/l to 15.62mg/l. • System was found to have a 98.4% BOD reduction

19. Recommendations • The first compartment of the ABR should be modified and increased in size to trap as much solids as possible. • The ABR should be made air tight and a system to improve/increase the pressure of the biogas in the reactor to allow gas collection otherwise the first compartment can be constructed in such a way that it has a gas holder and made airtight (shape of a fixed dome). • A gradient should be created between the ABR and the CW so as to utilize gravity as the driving force. • Wastewater monitoring/ testing should be done on a regular basis in order to ensure that the content of waste flowing to the stream conforms with the NEMA standards and as a way of monitoring the performance of the system.

20. References • Muench, E. (2008): Overview of anaerobic treatment options for sustainable sanitation systems. In: BGR Symposium "Coupling Sustainable Sanitation and Groundwater Protection". • Bachmann, A., Beard, VL. and McCarty, PL. (1985). Performance Characteristics of the Anaerobic Baffled Reactor. Water Research 19 (1): 99–106. • Sergio S. Domingos (2011), Thesis on Vertical flow constructed wetlands for the treatment of inorganic industrial wastewater, Murdoch University WA, Australia. • Morel A. and Diener S. (2006). Greywater Management in Low and Middle-Income Countries, Review of diff erent treatment systems for households or neighbourhoods. Swiss Federal Institute of Aquatic Science and Technology (Eawag). Dubendorf, Switzerland. • Nijaguna B.T. (2002), Biogas Technology, New Age International (P) Limited, New Delhi.

21. References • Rustige H &Platzer Chr. (2000),Nutrient Removal in Subsurface Flow Constructed Wetlands for Application in sensitive Regions in: Proceedings – 7th Int. Conf. On Wetland Systems for Water Pollution Control, Orlando, USA • Leslie Grady .C, Glen .T, (1999), Biological Wastewater treatment, 2nded, Maral Dekker ,Inc, New York • Foxon KM, Pillay S, Lalbahadur T, Rodda N, Holder F, Buckley CA (2004) The anaerobic baffled reactor(ABR): An appropriate technology for on-site sanitation. Water South Africa 30, 44-50. • Lawrence A.W. and McCarty p.L (1970): Unified basis for biological Treatment Design and Operation. J. Sanit. Eng. Div., Am. Soc. CivEngrs. • Walter R.H., Shermah R.M. and Downing D.L. (1974): Reduction in Oxygen demand of abattoir effluent by Precipitation with metal. J. Agric. FdChem

22. THANK YOU