Experience with an up-flow biological aerated filter (BAF) for tertiary treatment: from pilot trials to full scale implementation.
Biofilters can be added to existing non-nitrifying activated sludge plants for tertiary ammonia removal and effluent polishing. It is a convenient, efficient, and cost effective way of meeting more stringent consents. In order to prove this technology, a biofilter pilot plant was installed in a large activated sludge plant with challenging conditions, since almost half of the load is industrial effluent and the water temperature can be as low as 7 degrees C. Trials were conducted over a two year period, providing the following information: low water temperature does not affect the process; the optimum rise rate at nominal flow is 8.5 m/h for this wastewater; the consent can be achieved for ammonia loads up to 0.94 kgNH4N/M3 media/day; about 50% of the post-secondary TSS and BOD can be removed in the BAF; a large proportion of industrial effluent has not had any noticeable effect on the beads after two years. A full scale plant with a nominal flow of 8257 l/s was then built and commissioned in summer 1998. Seeding was completed within three weeks of starting the filters. Two months later, a 28 day takeover was started. Results obtained on full scale plant during and after this test confirm the results obtained on the pilot.
Payraudeau
M
M
OTV, L'Aquarène, Saint-Maurice, France.
Pearce
A R
AR
Goldsmith
R
R
Bigot
B
B
Wicquart
F
F
D000641:Ammonia / Q000737:chemistry / Q000378:metabolism*; D001673:Biodegradation, Environmental; D004867:Equipment Design; D005374:Filtration; D007220:Industrial Waste; D009584:Nitrogen / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism*; D011786:Quality Control; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods / Q000592:standards; D014872:Water Movements; D018508:Water Purification / Q000379:methods* / Q000592:standards
D007220:Industrial Waste; D012722:Sewage; D000641:Ammonia; D009584:Nitrogen; D010100:Oxygen