Removal Efficiency Of SS Research Articles

Organic matter and nitrogen removal by an on site sewage treatment and disposal system

The performance of an on site sewage treatment and disposal system consisting of a septic tank, a gravel filter, a sand filter and soil absorption trenches operated alternatively, was studied in relation to organic matter and nitrogen removal efficiency. The system was simulated with the aid of a laboratory scale model. BOD 5 and SS removal efficiencies averaged 92.9 and 93.4% respectively. Substantial removal of nitrogen (up to 70%) was achieved due to nitrification followed by denitrification. Removal efficiencies were found to depend on the compaction characteristics of the filter media and the soil, the hydraulic loading applied and the flow conditions (saturated/unsaturated). The results indicate that the system under consideration is a feasible alternative for on site treatment and disposal of domestic sewage.

Investigation to replace the conventional sedimentation tank by a microstrainer in the rotating disc system

The function of the microstrainer in removing suspended solids from the effluent of the rotating disc system was studied. Furthermore the SS removal efficiency of the microstrainer was compared with that of the conventional sedimentation tank. It was found that in connection with the complete biological treatment in the rotating disc system, the microstrainer was more efficient in removing suspended solids than the conventional sedimentation tank, and that under the dry-weather-flow condition an effluent SS concentration of 10 mg 1 −1 could be obtained with the microstrainer at a surface loading rate of 10–15 m h −1.