| dc.description.abstract | Wastewater treatment plants (WWTPs) operate on natural processes in
removal of Biochemical oxygen Demand (BOD), Oxygen chemical
(COD), nutrients organic carbon, and pathogenic microorganisms from
wastewater. Wastewater treatment produce considerable amount of
greenhouse gases largely methane during their operations. Reducing
these emissions from the treatment process and the contribution of the
wastewater treatment plants is important in reducing green house gas
effects into the environment. This can also allow recuperating energy,
and nutrients, thus reclaiming of treated wastewater in less developed
countries can be of importance in boosting the energy sources as well
as improve in Economies of these countries. It is therefore important to
understand how these emissions can be computed and get
documented. This research has attempted to estimate and compute the
greenhouse gases, primarily methane, emissions from Dandora
Sewage Treatment Plant (DSTP) in Nairobi Kenya using the
Intergovernmental Panel in Climate Change (IPCC) Guidelines (1996)
and IPCC Good Practice Guidance (2000).Operations data from year
2007 to year 2013 was obtained from Nairobi City Water and
Sewerage Company (NCWSC), the operator at the plant and analysed
to determine the average BOD loading rate and flows to the Plant as
well as the BOD removal rate across the anaerobic ponds from which
the amount of methane being generated by the DSTP was computed.
The average BOD loading rate and effluent to and from the anaerobic
ponds of DSTP was 454.11mg/l and 120.82 mg/l respectively between
year 2007 and 2013.This was 88.7% of the design capacity of 512mg/l.
The plant received an average of 83,648.30 m3/day which was
52.28% of the design capacity of 160,000m3/day from year 2007 to
year 2013.This represented a BOD mass loading of 37,985.53kg/day
against a designed capacity of 81,920kg/day which was 46.37%.Thus
DSTP has been operating at about 50%.
The plant generated an average of 11.29m3/day of methane from year
2007 to year 2013 at the current flows and can generate an average of
14.1m3/day of methane at a full capacity of 160,000m3/day at a BOD
loading of 512mg/l.
Methane generated from the anaerobic ponds at the plant can be
collected using floating covers and be used to generate electricity that
can be imported into the national grid at a feed in tariff ,be used in
operations of the plant or be sued for carbon credits. This would
increase revenue to the operator as well as prevent methane being
released into the atmosphere as it is the case now. | en_US |
