High performance biofilm process for treating wastewater discharged from coal refining plants containing nitrogen, cyanide and thiocyanate.
Wastewater discharge from coal refining plants contains a number of biologically toxic compounds; 2000-2500 mg/l of COD of which 40% is composed of phenol, 100-400 mg/l of thiocyanate, 10-40 mg/l of cyanide, 100-250 mg/l of NH4+-N and 150-300 mg/l of total nitrogen. In order to treat this kind of high strength wastewater, we have developed a high performance biofilm process using fluidizing bio-carriers of the tube chip type. The fluidizing biofilm carriers are made of a composite of polyethylene and several inorganic materials, whose density is controlled at 0.97-0.98 g/ml. The fluidizing biofilm carriers show sound fluidization characteristics inside bioreactors. The wastewater is treated using three consecutive series reactors in oxic-anoxic-oxic arrangement. Each reactor is charged with the fluidizing biofilm carriers of 50 vol%. Furthermore, newly cultured active microorganisms for the thiocyanate biodegradation are added in the biofilm process. At total hydraulic retention time of 2.2 days, this process can achieve steady state removal efficiencies: COD, 99%; thiocyanate, 99%; NH4+-N, 99% and total nitrogen, 90%.
Jeong
Y
Y
School of Environmental Science & Technology, POSTECH, Pohang, Korea. jys@postech.ac.kr
Park
B G
BG
Chung
J S
JS
D000332:Aerobiosis; D018441:Biofilms; D019149:Bioreactors; D002244:Carbon / Q000302:isolation & purification; D003031:Coal; D003486:Cyanides / Q000302:isolation & purification*; D007220:Industrial Waste; D009584:Nitrogen / Q000302:isolation & purification*; D010100:Oxygen / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D020959:Polyethylene / Q000737:chemistry; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D013861:Thiocyanates / Q000302:isolation & purification*; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*
D003031:Coal; D003486:Cyanides; D007220:Industrial Waste; D012722:Sewage; D013861:Thiocyanates; D002244:Carbon; D020959:Polyethylene; D009584:Nitrogen; C031760:thiocyanate; D010100:Oxygen