Application of pilot scale trickling filter couple with pre-ozonation for ammonia, iron and dissolved organic carbon removals from Saigon river water
Abstract
A pilot scale trickling filter and pre-ozonation contactor with capacity of about 20 m3/day was run at Hoa Phu Pump Station which takes raw water from Saigon River for drinking water supply for Ho Chi Minh City. The raw water contains 0.52 ± 0.19 mg NH4+-N/l, 0.14 ± 0,06 mg/l total iron and 3.14 ± 0.45 mg/l DOC. The study aimed to using the pilot scale experiment to assess ammonia, iron and dissolved organic carbon (DOC) removals from Saigon Water River for the sake of reducing chlorine demand and thus mitigating risk from Disinfection By Products (DBPs) formation. The size of the trickling filter was 0.5 m long x 0.5 wide x 2m high. The bio-media was seven PE wool sheets with thickness of 30 mm that is widely used as filter cloth in aquariums. It run at hydraulic loading of 3 m3/m2.h of raw water, and 8 m3/m2.h, where 50% of total flow was the returned effluent of pre-ozonation. The pilot scale pre-ozonation contactor which has the size of 0.6 m long x 0.6 m wide x 2.0 m high was operated at contact time of 15 minutes and ozone concentration of 0.5 mg/l. The ammonia, iron and DOC removals at 8 m3/m2.h were 58%, 25% and 22%, respectively. Whereas, it obtained ammonia, iron and DOC removals of 52%, 19% and 9% DOC respectively. Thus, even though the experiment with returned pre-ozonation effluent run at high hydraulic loading rate, the better performance was obtained as comparison to the experiment without return.