Studies On The Design And Purification Performance To Aquatic Wastewater Of Constructed Wetland

For recycling aquatics wastewater in BaiYun lake area,we designed a kind of wastewater treatment system based on constructed wetland.These constructed wetlands were vertical flow constructed wetland combining downward flow-upward flow.Three kinds of fillers were laid on the bottom of constructed wetland.Phragmitis communis,Typha angustifolia, Sagittaria sagittifolia,Phragmitis communis+ Typha angustifolia,Phragmitis communis+ Sagittaria sagittifolia,Typha angustifolia +Sagittaria sagittifolia, Phragmitis communis+ Typha angustifolia+ Sagittaria sagittifolia were planted separately in seven constructed wetlands.After constructed wetlands be used for four months,The plants had well-grown in constructed wetlands, Average load of constructed wetlands was 1.12m³/(m²Â·d),the capacity of wastewater treatment was about 800t every day,the time of water remaining in wetlands was 15h.Through determining microbial amount twice and determining physical and chemical parameter and pollute target-TN,TP,COD,NH₄⁺-N of ingoing and effluent water four times,we proved the effect of purifying aquatics wastewater by constructed wetlands,chose out the most suitable plants in wetlands.The result showed:the effect of water treatment was quite good in constructed wetlands.The water which purified achievedⅣ～Ⅴlevel standard required by Chinese environmental quality standard for surface water(GB3838—2002).Bacteric amount on surface of the plant root was more 1 amount class than on surface of the filler,this showed the purification performance of the plant was greater than the filler.Nitrobacteria amounts ofâ…£,â…¦pool were obvious greater than other pools,Nitrobacteria amounts of other pools were no obvious difference.This showed nitrification inâ…£,â…¦pool were obvious stronger than other pools-nitrification in constructed wetlands planted Phragmitis communis+ Typha angustifolia+ Sagittaria sagittifolia and Phragmitis communis+ Typha angustifolia were obvious stronger than others.The changes of the ingoing and effluent water-temperature in all kinds of constructed wetlands were not obvious,but the effluent water-temperature were higher than the ingoing water-temperature,this showed constructed wetlands could keep temperature.The changes of the ingoing and effluent water-transparency were obvious,this showed the effect of filtering out suspended matter and plankton in constructed wetlands was quite strong,the purification performance was quite good.Compared the concentration of DO. in ingoing and effluent water of constructed wetlands,the concentration of DO.descended slightly in effluent water.Compared the effects of removing TN,TP,COD and NH₄⁺-N in seven kinds of constructed wetlands,the effect of purifying wastewater by a kind of plant,Phragmitis communis＞Typha angustifolia＞Sagittaria sagittifolia;the effect of purifying wastewater by combination of there kinds of plants, Phragmitis communis+ Typha angustifolia+ Sagittaria sagittifolia＞Phragmitis communis+ Typha angustifolia＞Phragmitis communis+ Sagittaria sagittifolia＞Typha angustifolia +Sagittaria sagittifolia.The capability of removing different contaminations in aquatics wastewater was NH₄⁺-N＞TP＞TN＞COD.The average removing rates to NH₄⁺-N,TP,TN,COD of all pools were separate81.3%,80.5%,55.6%,54.7%.