Effect of hydraulic loading variations on the performance of decentralized small scale activated sludge treatment plant.

摘要

A compact decentralized small scale activated sludge treatment plant receiving domestic waste water was monitored over 12-month period. The plant was constructed, so that carbonaceous and nitrogenous bioreactions are to take place. The plant was operated at different hydraulic loadings (15, 20, 30 and 40 m3/d) to investigate the plant performance at varying conditions and to check for its absorbance capacity for possible shock loadings as a result of fluctuating influent quality. Carbonaceous kinetic coefficients based on Monod kinetics were determined. It has been found, that the plant was operated properly under different hydraulic loadings and produced a water quality that complies with the lowest Jordanian Standard 893-2006, which set an allowable maximum level of 30 mg-BOD₅/litre and 100 mg-COD/litre for irrigating vegetables, parks, playgrounds and roadsides within city limits. The results showed clearly, that the plant is sufficiently capable to absorb the organic chock loadings, which is expected in small treatment systems. Nutrient (nitrogen and phosphorus) removals were found to be very efficient, so that maximum ammonium and phosphorus removals were found to be 90 and 70%, respectively. The obtained kinetic coefficients showed clearly, that this treatment facility is able to biodegrade this type of waste water with low excess sludge production.