Study On The Integrated Device Consists Of Modified MST And Constructed Wetland

There are a great many small towns in our country and they widespread in many places, but the research about decentralized wastewater treatment technology for small towns was still in the initial stage, lacking specialized design specifications and standards as well as targeted and complete sets of equipments, integrated equipment is becoming a hot spot of research in recent years because of its advantages of less needs of land?better effect of treatment and less investment. MST integrated device was based on the biological contact oxidation and biological fluidized bed, the combination with artificial floating islands improves its effect of treatment, now we make artificial wetlands as the deeper treatment process, study the treatment effect of the pilot scale experiment device, providing the decentralized sewage treatment of small towns with new ideas and references.The results of the study are as followed:1)Make sure the total treatment amount of the device is above 5m3/d, through comparative trials under different working conditions, we determine the best rate of inflow was 0.22 m3/h, the best gas-water ratio was 10:1 and 17.1:1 respectively in the reaction zones of suspended filler and gas stripping, the hydraulic retention time was 37 h, the hydraulic loading was 2.88m3/(m3·d) and 4.61m3/(m3·d) respectively in the reaction zones of suspended filler and gas stripping, the concentration of COD?NH4+-N?TN?SS in effluent meet the part standards of Water Quality Standard for Scenic Environment Use and Water Quality Standard for Urban Miscellaneous Water Consumption or A standard of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant after the treatment of the modified MST integrated device.2)The water from the device enters artificial wetland for deeper processing, the removal rate of CODCr?NH4+-N?TN?TP improved in different extent. The concentration of the pollutions in artificial effluent except TP can satisfy the 3rd standard of surface water. The temperature has a big influence on treatment effect of artificial wetland, the removal rate for pollution in summer of artificial wetland is higher than in winter, aquatic plant and the substrate packing in wetland are also important elements that have great influence effect on the treatment effect, processing load as a key factor also influence the treatment effect of artificial wetland.3)The combination of modified MST integrated device and vertical undercurrent of artificial wetlands has a good ability to resist the fluctuant load, the influent quality in wastewater treatment plant has relatively large fluctuations,the average removal rate of COD reaches 86.66%,the average removal rate of COD reaches 95% and even higher, the average removal rate of TN reaches 63%, the concentration of CODcr?NH4+-N in effluent of the system can satisfy the requirement of level 3rd standard of surface water(CODcr?20mg/L?NH4+-N?1.0mg/L); the concentration of TN in effluent can also meet the A standard; total phosphorus treatment effect of the device is relatively poor,but the concentration of TP in effluent of artificial wetland can satisfy the requirement of level of A standard.4)The combination of modified MST integrated device and vertical undercurrent of artificial wetlands also has the characters of less needs for land?less sludge production?simple operation and even can realize automatic control?convenient management and maintenance and so on, the artificial floating islands and artificial wetlands also have a high value in ecosystem aspect, not only can purify the water body but also beautify the environment at the same time.5)It is feasible to apply the integrated device to treat the decentralized sewage of the small town, which provides the wastewater treatment plant in small town which was located in Chaohu river basin with technology reference, achieve the design prospect of the pilot scale experiment.