Low Cost Wastewater Treatment in Small Towns and Rural Areas by SimplyConstructed Alternate Aerated Ponds

Abstract:

A simplyconstructed alternate aerated pond was proposed based on the integration of Unitank,trichannel oxidation ditch and aerated pond.Results show that the side tank plays key role in denitrification and dephosphorization,and the ideal performance can only be achieved by artful setting for inflow and aeration in side tank.Under the optimized control mode,cycling time=6h,ratio of inflowside tank to inflowmiddle tank=2,ratio of aeration time to inflow time for the whole system=1,and ratio of aeration time to inflow time for side tank=0.5.Running by this mode can maintain the activity and concentration of sludge,and attain a good balance of denitrification and dephosphorization,so that effluent reached Level-1 B of China’s Discharge standard of pollutants for municipal wastewater treatment plant.By two years’ full scale operation,simplyconstructed alternate aerated pond is proved to be a useful method for water pollution control in Chinese rural towns with its advantages of low cost,simple maintenance and good effluent quality.

Key words:rural town; denitrification; dephosphorization; simplyconstructed alternate aerated pond