Fecal coliform removal in a sulfate reduction, autotrophic denitrification and nitrification integrated (SANI) process for saline sewage treatment.

The Sulfate Reduction, Autotrophic Denitrification, Nitrification Integrated (SANI) process has been specially designed to treat saline wastewater. In the process no biological excess sludge is produced. SANI process also has the added advantages of cost and footprint reduction when compared to traditional activated sludge processes. In the SANI pilot plant, the fecal coliform removal efficiency in the sulfate reducing up-flow sludge bed (SRUSB) was found to be 1.4 log, whereas that in the subsequent anoxic and aerobic reactors it was 0.6 and 0.2 log, respectively, leading to a relatively high overall coliform removal of 2.2 log. Sulfide was confirmed to be toxic to fecal coliform and the contact time between the sulfide produced and coliform in the SRUSB played an important role in the removal.