With good biodegradability, domestic sewage is mainly derived from bath waste water, kitchen waster water and toilet-flushing water, usually applies A/O, Anoxic/Oxic treatment, effectively reduces content of COD, BOD and NH-N and meets the national discharged standard of sewage. Moreever, deeper treatment with M/F, Multi media filtration/ Ultrafiltration can further remove sewage suspensions and organic matter, decrease the sewage turbidity and chroma. The deeper treated waste water can be used as domestic miscellaneous water for washing cars, flushing toilet, greenery and architecture water usage, etc.