Study On The Treatment Of Rural Domestic Wastewater By RBC And APFB Technology

Taihu was one of the three big lakes in our country.In recent years,by the developmemt of economic ,The eutrophic degree of Lake Taihu has descended,specially the non-point pollution in Lake Taihu area has been the most important one for the pollution contribution with the serious pollution of nitrogen and PHosPHorus.So the disposition,pollution control,Ecological Restoration of water circumstance in Lake Taihu area has become the most imperative thing that will be done. This full-scale experimental study belongs to the subject about technology and demonstrative engineering for rural domestic wastewater treatment which is one part of the 863 tasks. Combined with the rural fact complexion,the advanced treatment progress and technology which can treat rural domestic sewage in Lake Taihu area effectively will be provided.With the experimental data,the optimal running conditions are obtained which can provide the experiences for continued treatment tasks.Based on these Aerobic Rotating biological contactor(RBC) and Aquatic plant filter bed (APFB) combined processes for treating rural domestic wastewater are designed.The following conclusions can be arrived at during the practice:1.The loads of process,hydraulic load and circumfluence ratio influence the treatment effect of RBC,the best treatment effect can be obtained at the following level:COD cubage load was 0.93kgCOD/m3·d, NH4+-N cubage load≤0.61kgCOD/m3·d,hydraulic load is 3.24m3/m2·d, circumfluence ratio is 100%.The RBC can gain good disposal effect..2.The COD removal ritio of the 3td class biological rotating contactor were 21%,12%和9%, The NH4+-N removel ritio was47%,25%和17%。3. Using fluorescence in situ hybridization (FISH) ,it is found that the microorganisms inside RBC is at 1012cells/g biofilm level and the 3td class biological rotating contactor ,distribution cases which reduced.The nitrosomonases are less than nitrobacters within the whole RBC.The effect of nitration in RBC has a positive correlation with the amounts of nitrifying bacterias.4. By the dynamics evaluation of nitrification and denitrification potential for biomembrane in the RBC, it is found that the maximum nitrification potential is in second turnplate. maximum denitrification potentialof the Denitrification Contactor is in the bottom.5. Aquatic plant filter bed (APFB) is a new type of technique combining plant purification and physical filtration for constructed wetlands without any substrate that applied mainly to purification of hyper-eutrophic surface water.The removal of COD,TN and TP was 31%,39%,64% respectively.The main mechanism of nitrogen in filter bed is the action of microorganisms, The main mechanism of Phosphorus removal is the adsorption and sedimentation. while the phosphorus removal efficiency will increase by the reaction of Ca+ with phosphate in wastewater.