Effect Evaluation on Non-hazardous Latrine in Rural Areas of Guangdong Province

Objectives To investigate the latrine improvement in rural areas of Guangdong Province in 2011 and evaluate the effect of the non-hazardous treatment of the septic tank so as to supply the evidence for policy-making.

Methods Three counties were randomly chosen through stratified cluster sampling in the whole province. And three latrine improvement villages and three non-latrine improvement villages were randomly chosen in each survey county, and in each village 30 families were randomly chosen and surveyed. Meanwhile, the samples were collected from the inlet and outlet of 45 "three-grille mode" septic tanks.The parasite eggs, chemical oxygen demand (CODcr), nitrate nitrogen, nitrite nitrogen, ammonia nitrogen (NH₃-N) and fecal coliform (FC) were tested in lab.The quality rate of FC, detection rate of parasite eggs, removal rates of CODcr, nitrate nitrogen, nitrite nitrogen and NH₃-N were calculated.

Results During these septic tanks, the construction quality pass rate of latrine improvement families was significantly higher than those of non-latrine improvement families. In the 135 samples, the mean quality rates of FC in the inlet, outlet of the septic tank and non-sanitary latrines were 93.33%, 100% and 86.67%, respectively.The detection rate of parasite eggs were 55.56%, 4.44% and 51.11%, respectively.The mean removal rates of CODcr, NH₃-N, nitrate nitrogen and nitrite nitrogen of the septic tank were 58.02%、42.93%, 34.08% and 85.0%, respectively.

Conclusions In 2011, the effect of non-hazardous latrine in Guangdong Province was obvious, which had a good effect of destroying FC and parasite eggs.However, the removal abilities of CODcr, NH₃-N, nitrate nitrogen and nitrite nitrogen are non-ideal and should be further conducted.