Study And Engineering Application Of Preanoxic-BIOFOR Combination Technology

With the rapid development and expansion of industry, the source of high concentration organic wastewater increases day by day, which has brought serious pollution and harm to the environment. Based on the L-lactic acid production wastewater treatment project of a chemical plant in Jiangxi province, the paper studies the application prospect of pre-anoxic-BIOFOR combination wastewater treatment technology in the aspect of L-lactic acid production wastewater treatment. The actual project application indicates that the treatment effect of this technology is good, the effluent quality (COD, NH3-N, SS, pH) is able to meet the first class standard in Integrated Wastewater discharge Standard GB8978-1996. The removal rate of COD, NH3-N, SS are all above 95%, 93%, 97%, pH value is about 7.Through researching the mechanism of biological nitrification and denitrification and actual project application of the technology and related literature materials, the obtained results are as follows:(1) Anoxybiosis is effective to the removal of COD; after the anoxic process, BOD/COD of the outflow increases, it shows that the degradation ability of wastewater is improved; anoxybiosis is insensitive when shock loading of inflow wastewater varies greatly;(2) It is demonstrated by the operation of inoculation and cultivating that biofilm takes two weeks to succeed in cultivating on packings and the removal ratios of NH3-N and COD get 50% and 70% respectively, when gas-water ratio is 6:1, HRT is 7.3 hour, water temperature is above 15°C;(3) It is demonstrated that gas-water ratio, hydraulic loading, HRT, temperature, pH etc are important factors which influence the removal effect of pollutants, when the gas-water ratio is 6:1, hydraulic loading is about 0.38kgNH3-N/m~3.d, water temperature ranges from 15°C to 27°C, pH ranges from 7.5 to 8.0, the BIOFOR removal effect of pollutants is the best;(4) The operation indicated that, this technology has strong ability of nitrification and denitrification; it has extremely vital significance for reducing the water body eutrophication;(5) It is confirmed the feasibility and the usability of preanoxic-BIOFOR process to treat L-lactic acid production wastewater. The experiment indicated that the treatment effect of this technology is very good and also shows that the technology has many advantages, such as small volume, high treatment efficiency, good effluent quality and strong endurance to load variation, this technology is a new and economical wastewater treatment process.