Abstract
The reclaimed wastewater quality in 39 treatment facilities of combined household wastewater for individual houses were investigated in the rural area in Ehime Prefecture, in Japan. The mean values of SS·BOD·COD·T-P·T-N were 8.70mg·L-1, 12.0mg·L-1, 25.3mg·L-1, 3.69mg·L-1, 23.6mg·L-1, respectively. The SS·BOD·T-N concentrations decreased when the return flow devices were continuously operated. The COD·T-N concentrations decreased when it was shorter period since the cleaning, including back washing and sludge carry out. Based on the results, the availability, limitation and the key of the better management practices of the treatment systems to the water quality conservation in Japanese rural area were also discussed.
