Exploration And Practice Of On-site Treatment And Resource Utilization Of Kitchen Wastewater

Food and kitchen wastewater treatment has always been a difficult problem in the industry.Its source mainly includes two parts:food and beverage raw materials,tableware cleaning sewage;kitchen garbage collection,waste water generated in the process of treatment.Food and kitchen wastewater has the characteristics of high COD,high SS,high oil content,easy corruption and unstable incoming.It has a certain impact on municipal sewage pipeline and sewage treatment plants,if the wastewater has been directly discharged.The easily corrupted suspended matter easily attaches to the pipeline network,and produces foul gas and methane,which not only affects the surrounding environment,but also has security risk.This topic mainly aims at some large-scale enterprises or crowd gathering places,and remote tourist attractions,etc.,the production of kitchen sewage is large,centralized sewage treatment facilities,pipe network can not be matched in place or take over the place of high discharge requirements at present.Combining with the sewage treatment and reclaimed water reuse process with many successful cases,the centralized treatment of kitchen sewage source and the optimization of reclaimed water reuse process are tried.On the basis of a practical sewage treatment project in a dining hall of Wuxi factory,a pilot test was conducted to sample the actual wastewater.According to the test results,the project technological route was determined,and the technological process design and equipment selection were carried out.Through experimental analysis,the"oil separation+physicochemical+biochemical+MBR"process was used to treat kitchen wastewater.After treatment,all the effluent is reused for flushing toilets in the production workshop.Through the analysis of debugging and running data of actual projects,the results show that the average amount of kitchen wastewater in the factory is 74.5m³/d,The influent water quality:the COD concentration?4000mg/L,the NH₃-N concentration?35mg/L,the TN concentration?70mg/L,the TP concentration?10mg/L.After treatment with the above process,the effluent water quality:the COD concentration?70mg/L,the NH₃-N concentration?2.5mg/L,the TN concentration?10mg/L,the TP concentration?0.5mg/L,which can meet the requirements of"Water Quality of Urban Wastewater Recycling and Utilization of Urban Miscellaneous Water"GB/T18920-2002on toilet flushing.After calculation,the cost of water treatment is 9.83 yuan/t,taking into account the cost of electricity,chemicals,labor,sludge treatment and membrane replacement.The successful operation experience and operation data of this project can provide some important reference for the design and operation of new similar kitchen sewage treatment projects.The sewage after treated is reused in the factory area to reduce the primary clean water consumption?municipal water supply?and save 333.5 yuan per day?annual water consumption can be reduced by 121727.5 yuan?.For remote areas where water resources are scarce and municipal sewage treatment facilities are not in place,it can also reduce the burden of municipal water supply and drainage network?increase the potential scope of services of subsequent municipal sewage plants?,which has certain economic benefits and demonstration effect.