| According to the problems that traditional constructed wetlands has low phosphorus and nitrogen removal performance and large areas, the group has exploited sequence constructed wetlands system during earlier stage which solve the problem about low nitrogen removal performance commendably. On this basis, deep sequence constructed wetlands (DSCW) is proposed. In order to substantially reduce the areas of constructed wetlands, depth of wetland systems is increased. Meanwhile, for reinforcing phosphorus removal efficiency and stabilization of treatment efficiency, on account of constructed wetlands micro-electrolysis packing is exploited. The effect of depth on the efficiency of DSCW is set research priorities. Through studying the factors about filler particle size, operation condition, winter temperature and wetlands series, key condition parameters for DSCW is fixed. Furthermore, micro-electrolysis packing is firstly used to dispose of sewage in wetland systems. Treatment efficiency of Ferric-carbon filler and Alumina-carbon filler are respectively studied; the effect and mechanism of dealing with sewage by Ferric-carbon micro-electrolysis packing are studied through the factors about pH, reaction time, organic loading, filler particle size and match. The effects of pH,loading and reaction time on micro-electrolysis filler treatment efficiency are studied by orthogonal test, and orthogonal regression equation is obtained which concern the effects of pH, organic loading and reaction time on treatment efficiency. Major conclusions of the study are as follows:The result of depth effect experiment showed that when the depth of DSCW system is 0.55m, 1.1m and 1.9m respectively, the COD removal rate is 83.9%,85.0% and 82.4% respectively, the NH4+-N removal rate is 48.3%,56.9% and 57.1% respectively, the TN removal rate of 48.5%,53.2% and 42.6% respectively, the PO43--P removal rate is 57.3%,67.0% and 67.5% respectively. The increase of depth of Sequencing Batch Artificial wetland system has no significant influence to its treatment efficiency. DSCW system area load is 146.7gCOD/m3·d, 35.7 gTN/m3·d and 2.4gPO43-/m3·d respectively, which is raised by 93.4 gCOD/m3.d, 26.9gTN/m3·d and 1.53gPO43-/m3·d respectively when compared to traditional Artificial wetland. Land occupation for processing unit water is 1.87m2/(m3·wastewater) and 80% less in land occupation.The result of running condition showed that When the water temperature is 20℃~ 30℃, optimal operating condition of DSCW is"inlet water 8min~reaction 12h~ outlet water 8min~ idle 12h".Compared with idle time of 4h in shallow bed SCW system of depth of 0.5m, idle time of DSCW system is tripled.The result of efficiency of winter showed that in comparison of one-stage DSCW, the efficiency of two-stage DSCW system is enhanced significantly. When the water temperature is 8℃～10℃, the influent COD, NH4+-N, TN and PO43--P is 253mg/L, 59.3mg/L, 69.6mg/L and 4.7mg/L respectively, the effluent is 12.4mg/L,15.0mg/L,14.8mg/L and 1.2mg/L respectively. Total removal rate is 95%, 74.7%, 78.7% and 78.0% respectively. The share rate of COD, NH4+-N, TN and PO43--P removal in the first stage of DSCW system is 72.0%, 38.9%, 41.1% and 58.0% respectively, the second stage is 22.4%, 38.1%, 35.2% and19.1% respectively. Of these, the effluent of COD and TN meet the first-level A standards in (GB18918-2002).the effluent of NH3-N first-level B standards, the effluent of PO43--P is close to first-level B standards. Land occupation for processing unit water is 3.8m2/(m3·wastewater).The result of single influential factor experiment of Ferric-carbon micro-electrolysis filler for processing domestic sewage showed that the optimal operating condition of system is the influent pH is 7~8, reaction time is 3h, load is 1.39kgCOD/(m3 Ferric-carbon·d), volume ratio of Fe/C is 1:1, particle size of scrap iron and activated carbon is 16 orders. Under the optimal operating condition, the influent of domestic sewage COD, NH4+-N,TN and PO43--P is 300mg/L, 57.4mg/L, 66.0mg/L and 4.1mg/L respectively, the effluent decrease to 61.3mg/L, 16.9mg/L, 17.3mg/L and 0.1mg/L respectively and removal rate is 78.5%, 74.9%, 77.5% and 98% respectively. As operating time increased, the removal capability of COD and PO43--P of Ferric-carbon micro-electrolysis system shows good stability,but he removal capability of NH4+-N shows downward trend.The result of orthogonal test of Ferric-carbon micro-electrolysis filler showed that the factor which has significant influence to COD, NH4+-N and PO43--P removal efficiency is load, pH,reaction time and load , reaction time. The orthogonal regression equation of comprehensive influence of Load, pH, and reaction time to Ferric-carbon micro-electrolysis system is respectively.ηCOD(%)=85.7+1.15pH-37.2T+1.45NηNH3(%)=42.8+3.25pH -28.8T +2.6NηPO43-(%)=96.8-0.6pH+2.8T-0.7NThe study target is to solve bottleneck problem about the application of CW, which has relatively strong pertinence. Exploited technology of DSCW has excellent adaptability and popularization and application value in small town and the rural area which has little land. The development of micro-electrolysis filler will enhance treatment efficiency and stabilization of wetland systems. It has an important practical value and practical significance.
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