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THE POTENTIAL OF WASTE STABILIZATION PONDS EFFLUENT AS A LIQUID
FERTILIZER
MOAZZAM
ALI KHAN AND M. ALTAF KHAN
Abstract:
This
research investigation was aimed at demonstrating the technical and
economic feasibility of waste stabilization ponds (WSP) under the
climatic conditions of a subtropical region. A pilot plant was designed
and constructed at the Karachi University Campus (KUC) for the treatment
of domestic wastewater. An intensive analytical programme was followed
for 24 months to evaluate the performance of ponding system. The
algal-bacterial symbiotic system performed satisfactorily and achieved
total BOD5 removal upto 80 - 82%, COD 69-74%, NH3-N
9-52%, Total Kjeldahl nitrogen (TKN) 38-47% and PO4-P ranging
between 34 to 38 % in the secondary pond (P-4) at very high organic
loadings of 500 and 1168 kg/ha.d. The maximum efficiency for the removal
of coliforms was 99%. The study demonstrated that high BOD5
loadings at 500 and 1168 kg/ha.d were possible without deteriorating the
performance of WSP. The
research investigation practically demonstrated that WSP treatment
technology is economically viable, as the effluent has been shown to be
useful as a liquid fertilizer being rich in plant nutrients (N, K, P).
An economic analysis of the treatment of 1000,000 gallons of wastewater
indicated a net profit of Rs 7673 in addition to social and
environmental benefits. At the same time this approach could conserve
equivalent quantity of potable water, which is always, in short supply
in mega cities like Karachi.
Institute
of Environmental Studies,
University
of Karachi, Karachi-75270, Pakistan.
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