Abstract
In order to investigate microfauna in activated sludge treating livestock wastewater for control of treatment performance and effluent quality, mixed liquor of intermittent aeration process (pilot scale) and extended aeration process (full scale) were examined microscopically during a year.
The numbers of microanimal species found in activated sludge of intermittent aeration and extended aeration were 16 sp. and 13 sp., respectively. Observed microanimal species was very few in comparison with microfauna of other biological wastewater treatment system. Microfauna in a livestock wastewater treatment system show characteristic and variations in species composition and density with response to SS removal, BOD removal and pH variation. Opercularia coarctata was considered useful indicator of BOD and T-N removal, however flagellated protozoa was only observed in mixed liquor when the percentage BOD removal was below 95% and NH4-N was accumulated in the reactor. There was a drastic change in microfauna which became dominant by Rhizopoda such as Euglypha sp., Cryptodifflugia oviformis and Trinema lineare with the accumulation of effluent NO3-N.
These results show microfauna in activated sludge treating livestock wastewater was valuable as indicators of system perfomance. In addition, it is clear that the indicator organisms observed in activated sludge treating sewage wastewater is possible to be applied to livestock wastewater treatment, in a similar way to their use for the mainanace of treatment system.
