Center for Environment and Energy Research and Studies (CEERS)
Abstract
The aim of the study was to investigate the nutrient removal rate of
three wastewater protozoan isolates. The study was carried out in a
laboratory-scale batch reactor for a period of 120 h. in a four batch
study. Aliquot samples were withdrawn from the reactor every 24 h. for
the analysis of phosphate, nitrate, nitrite, ammonia, chemical oxygen
demand, dissolved oxygen and pH, using standard methods. The results
obtained in the different batches among the three isolates showed PO42-
removal rate ranging from 0.04 to 0.52 mg-PO42-/L/h. while NO3- nitrate
removal rates ranged from 0.08 to 0.16 mg-NO3-/L /h. Also NO2- and NH3-
rates were observed to range between 0.022 and 0.087 mg-NO2-/L /h. 0.05
and 0.16 mg-NH3-/L /h, respectively. For the physicochemical
parameters, there was no observed COD decrease; rather there was an
increase and this was irrespective of isolates and experimental
batches. However, dissolved oxygen concentration decreased drastically
(below 1 mg/L) at the end of each batch while pH show a decrease after
an initial 24 h. period and thereafter increased. This trend was also
irrespective of isolates and experimental batches. Overall, the study
has been able to show the effect of the test isolates on nutrient
removal rates and other physicochemical parameters (COD, DO and pH) in
activated sludge mixed liquor
