Nitrification/denitrification in swine wastewater using porous ceramic sticks with plastic rings as supporting media in two-stage fixed-biofilm reactors.
This study evaluated the performance of oxic-anoxic fixed-biofilm reactors (FBRs) using porous ceramic sticks with plastic rings as supporting media for nitrogen and organic carbon (as COD) removal from swine wastewater. Experimental results indicate that the removal efficiency of NH(4)(+)-N increased to 86-92% from 52-98% as the volumetric ammonium-nitrogen loading rate increased to 0.25 kg NH(4)(+)-N/m(3)-d from 0.082 kg NH(4)(+)-N/m(3)-d. Furthermore, during the denitrifying column test, the average removal efficiencies for COD and NO(x)-N were 83 and 76%, respectively. Only small amounts of NO(2)(-)-N and NO(3)(-)-N accumulated in the denitrifying FBR. The average values for NO(2)(-)-N and NO(3)(-)-N in effluent from denitrifying reactor were roughly 2 mg/L and 6 mg/L, respectively. Approximately 82% of NO(3)(-)-N was converted into N(2) by denitrifying bacteria in the denitrifying FBR. Approximately 98-100% high removal efficiencies of NO(x)-N could be reached in denitrifying FBR, when the ratio of COD(r)/NO(x)-N(r) was controlled at 9-12 throughout the test. Microscopic observations show that cell number on the ceramic sticks in denitrifying FBR was greater than that in nitrifying FBR in the final phase of colonization.
Lin
Yen-Hui
YH
Department of Safety, Health and Environmental Engineering, Central Taiwan University of Science and Technology, Taichung 40601, Chinese Taiwan. yhlin1@ctust.edu.tw
D000383:Agriculture; D000818:Animals; D018441:Biofilms / Q000254:growth & development; D019149:Bioreactors; D002516:Ceramics; D004867:Equipment Design; D006799:Housing, Animal; D007220:Industrial Waste; D008855:Microscopy, Electron, Scanning; D009584:Nitrogen / Q000737:chemistry*; D009930:Organic Chemicals; D010969:Plastics; D013552:Swine; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000295:instrumentation*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
D007220:Industrial Waste; D009930:Organic Chemicals; D010969:Plastics; D014874:Water Pollutants, Chemical; D009584:Nitrogen