Mwangi Simon Thuku F21/2492/2009 Supervisors : Mr. Orodi Odhiambo - PowerPoint PPT Presentation

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mwangi simon thuku f21 2492 2009 supervisors mr orodi odhiambo eng d a mutuli

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

BACKGROUND

Approximated slaughterhouse waste content and NEMA standards for disposal into the environment

Johns et al., 1995; Manjunath et al., 2000, NEMA

BACKGROUNDCont’d

Treatment Options

Anaerobic treatment + activated sludge
Anaerobic treatment + contact aeration
Activated sludge + chemical coagulation
Contact aeration + chemical coagulation.

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

Site Analysis

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

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.

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

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

Theoretical Framework

Chemical oxygen demand,

Biochemical Oxygen Demand, BOD5,mg/L =

Sasse (1998), Wanasen (2003), Foxon et al., (2004) etc

Results

Results Cont’d

Leslie C.P. et al, 1999

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

Drawings

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

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.

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.

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