| With China’s social and economic development, water pollution is worsening, the recentnews about the contaminated water increased, the eutrophication of water body pollution hasbecome the focus of attention, including the China’s largest freshwater lake Poyang lake. Howto purify this class water of not easy to centralized collection treatment and different waterbodies contaminated degree, to protect Poyang lake water become a serious problem to besolved. Compared with traditional technology, the technique of constructed wetland,stabilization pond ecosystem to better highlight its characteristics, and the combination ofboth realize the complementation of the two can to advantage deep purification water quality,improve the water quality and stability, more suitable for this type polluted water treatment.But at the moment about the combination technology applied in polluted water treatment isrelatively small, can provide the corresponding design parameters are rare.This study mainly discusses the ecosystem combination system of constructed wetlandand stabilization pond in polluted water purification effect and the law of each pollutant,provide a reference for the practical application of combined system.First of all, starting fromthe selection of stabilization pond, chose8kinds of common pathogens of submerged planthas better purification effect on nitrogen and phosphorus pollutants combined with pond ineast China, forming the submerged plant pond, in-depth analysis of the system for sewagepurification effect and its mechanism, examine the stability of the system performance, thusfor combination system to select the most suitable submerged plant pond; Secondly on thebasis of determining stabilization pond, established two-stage combination system ofconstructed wetland and submerged plant pond to study the whole process and the variousstructures in combination treatment effect on water pollutants, and the effects of combinationssystem on pollutants removal under different hydraulic loading conditions; Finally based onthe two-stage combination system, set up various forms of constructed wetland and pondcombination process of multi-stage, exploratory discussion multi-stage combination processof serious pollution of water purification effect and the stability of the combination processperformance.This study get the following conclusion:1) the submerged plant pond test:The submerged plant pond of sewage removal effect is obvious.CODcrremoval rateranged from44.35to72.18%, of which the Ceratophyllum demersum, Myriophyllumaquaticum optimal removal effect of organic matter, achieved the Ⅳ class water quality of“environment quality standard for surface water”; TP, TDP, PO43--P removal ranged from 58.26-79.34%;60.00-83.91%;61.32-86.79%, are all Egeria densa were the highest, to reachthe Grade A standard of “discharge standard of pollutants for municipal wastewater treatmentplant”; TN, NH3-N removal rate is between44.05-61.54%and35.71-71.13%, TN removalCeratophyllum demersum effect is best, Egeria densa NH3-N removal efficiency, achieves theGrade A standard of “discharge standard of pollutants for municipal wastewater treatmentplant”. Eight different submerged plant water Ceratophyllum demersum, Myriophyllumaquaticum and Egeria densa removal effect is prominent, the pollutant removal rate is best,have good anti-load capacity, which Myriophyllum aquaticum more cold tolerancesignificantly, least influenced by the external environment, can be submerged plant inoptimization considering for the pond.Through the study found that the submerged plant pond degradation of organic mattermainly by precipitation, filtration, insoluble organic matter by microbial intercept and use,soluble organic matter degradation can be direct absorption and metabolism of microbes andplants; Remove part of the phosphorus pollutants directly absorbed by the plant, the main isstill the chemical precipitation and sedimentation adsorption; Remove part of nitrogenpollutants including plants uptake, microbial nitrification and denitrification, and thevolatilization of ammonia nitrogen, but the main removal effect remains to be further studied.2) two-stage combination process test:The combination process of constructed wetland and submerged plant pond in the wholerunning stability under different hydraulic loading and pollution load, load resistant capabilityis strong, the removal effect is good. CODcreffluent achieved to Ⅲ class standard of“environment quality standard for surface water” under low HLR, medium and high HLRachieved to Ⅱ class standard; Total phosphorus achieved to Ⅳ class standard of“environment quality standard for surface water” under low, high HLR, the medium HLRachieved to Ⅴ class standard;Total nitrogen are reaching the achieves the Grade A standardof “discharge standard of pollutants for municipal wastewater treatment plant”; Ammonianitrogen all reach the achieves the Grade B standard of “discharge standard of pollutants formunicipal wastewater treatment plant”.Hydraulic load of pollutants removal efficiency has a certain impact. The compositesystem with the increase of hydraulic load, average pollutant removal rate of CODcr:72.09,68.06,64.50%; TN:51.69,48.22,46.82%; Ammonia nitrogen:62.52,53.53,50.47%; TP:85.56,81.64,80.89%; Solubility orthophosphate:89.69,82.48,84.90%; indicating that inaddition to the soluble phosphate, other pollutants removal rate were reduced with theincrease of hydraulic load, low hydraulic load optimal removal effect. Constructed wetlandeach pollutant removal efficiency are low> medium> high hydraulic loading, and negativelycorrelation with hydraulic load; While stabilization pond CODcr: medium> high> low;ammonia nitrogen: low> medium> high; TN, TP, phosphate: high> low> medium,indicating less affected by hydraulic loading, and hydraulic loading no significant correlation. Combined system of wetlands and ponds in the removal of pollutants in differentcontribution rates. For CODcrwetlands in low, medium and high removal rate of threehydraulic loading:59.75,48.84,47.39%, while the pond is:30.45,39.11,33.87%, wetlandremoval effect is better than that of the submerged plant pond; But for nitrogen andphosphorus, the submerged plants pond with hydraulic load increases total nitrogen,ammonia nitrogen, total phosphorus, dissolved phosphorus removal rates were respectively:33.86,31.11,34.08%;53.89,43.71,43.18%;71.52,68.99,72.40%;70.95,69.48,74.84%,while wetlands26.71,24.87,18.81%;18.49,16.26,12.50%;48.94,38.85,29.95%;61.43,40.28,39.29%, submerged plants pond water eutrophication factors removal better thanwetlands.3) multi-stage combination process test:For this kind of serious pollution, high concentration and the mean C/N ratio less than1special polluted water, the system load resistant capability is strong, the whole system runningstability. Organic combination system mean value of119.61mg/L, the water outlet average of49.17mg/L, the average removal rate was58.58%, achieved to Grade A standard of“discharge standard of pollutants for municipal wastewater treatment plant”(50mg/L); Fillthe average total nitrogen concentration of126.50mg/L, ammonia nitrogen concentration of87.33mg/L, effluent is average54.00mg/L, total nitrogen ammonia nitrogen average36.91mg/L, removal rate are57.03%and57.03%respectively; Average total phosphorus into wateris0.11mg/L, the mean total p was0.03mg/L, water removal rate was69.61%, reached Ⅲclass standard of “environment quality standard for surface water”(lake, library0.05mg/L). |
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