Household wastewater treatment plants have been rapidly promoted in re
cent years as part of the measures for reducing the pollution loading
discharge from private households in Japan. The author; have developed
a high-efficiency household wastewater treatment plant employing a fl
ow equalisation anoxic-oxic recirculation biofilm process removing org
anic matter as well as nitrogen which causes eutrophication. A full-sc
ale experiment has been conducted for one year by leading actual grey
water (cooking, bathing, washing effluents) from a private household i
nto the experimental apparatus. The results obtained in this study are
summarised as follows: effective now equalisation and excellent efflu
ent quality were achieved, the maximum effluent flow rate was 100 l/h
(the peak coefficient 1.5) when the maximum influent flow rate was 415
l/h (the peak coefficient 6.2), the average values of BOD5, CODMn, SS
, T-N and T-P of the treated water were 7.8 mg/l, 11.1 mg/l, 5.9 mg/l,
6.4 mg/l and 1.2 mg/l, respectively BOD5 and T-N of the treated water
were less than 10 mg/l during the experimental period.