| Large production scale of distilled spirit in our country resulted in numerous wastewater discharge amount. Owing to high concentaions of organic, nitrogenous and phosphorus-containing matter as well as high colourity, the brewery wastewater is difficult for treatment. What’s more, with the implementation of the Discharge standard of Water pollutants for fermentation alcohol and distilled spirits industry (GB27631-2011), a higher level has been put forwarded for the brewery wastewater treatment. At present, many spirit-producing enterprises can not meet the new discharge standard and therefore face the challenge of stop production and rectification. It is imperative to upgrade and retrofit their old wastewater treatment stations.This research takes the reconstruction project of WenShui Co.,Ltd’s brewery wastewater treatment system as an example. Based on comprehensive analysis of the problems exsited in the old wastewater treatment station, the modification scheme, structure size and equipement model were determined through of craft selection and design calculation. A large number of first-hand data was get through anticipating the system debugging, trial operation and trouble shooting in operation phase. Then, a set of operational parameters and fault-resolving countermeasures were summarized and the technical and economic feasibility of this reformation scheme was proved.The main biological treatment process for the old wastewater station was comprised of anaerobic tower, traditional activated sludge aeration and bio-contact oxidation. It concluded UASB, A2O and biological contact oxidation tank after reconstruction. In order to eliminate the adverse effects of high suspended solids concentration on UASB, a primary settling tank was added before UASB. A chemical phosphorus removal unit was designed after the biological units to enhance the phosphorus removal efficiency. As regards equipments, variable orifice aerator aeration hoses was used, combined-type double ring filler was set in the bio-contact oxidation pond and a new serried-screw sludge dewatering machine replaced the old frame pressure filter.The conclusions were drawn as follows:(1) The challenges in brewery wastewater treatment lay in meeting the discharge standard of nitrogen and phosphorous. Choosing A2O as the main biological process and using polyaluminum chloride as the chemical phosphorus removing agent were reasonable.(2) Adding a primary settling tank before the UASB, adjusting pH with sodium hydroxide and recirculating a portion of UASB effluent and designing high-efficient water distribution system were of great importance to ensure and improve UASB performance.(3) The methods that improving the influent load stepwisely and taking volatile fatty acid concentration (<3 mmol/L) as an indicator were effective for the startup of UASB. Reduing the influent flux, rapidly increasing pH of the mixed liquid and starting a large ratio of effluent circulation could recover the acidified UASB effectively. Spare air blower could be used to solve the problem that aerobic sludge appeared black.(4) The combined-type double ring filler exhibited excellent performance in the bio-contact oxidation pond. The serried-screw sludge dewatering machine could replace the tranditional frame pressure filter due to its advantages such as compact configuration, small land demand, simple operation and high dehydrating efficiency.(5) The original operation cost was 10.93 CNY per cubic meter. After reconstruction, the operation cost was reduced to 8.55 CNY per cubic meter. |
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