Study On District Reclaimed Water Reuse With The Combination Process Of Coagulative Precipitation And Constructed Wetlands

According to the national policy guidance for reclaimed water reuse and the market and the technical demand of the residential district to treat waste water and reuse, in view of the tremendous influence on sewage regeneration craft running effectively due to small dimension and great changes in water quality and volume,to provide reliable and economical parameters suit for water treatment and reuse in community,the integrated coagulation precipitation treatment craft has strong ability adapting for water quality and volume change and works flexibly.With the constructed wetland craft process merits that it has high anti- impact hydraulic load,and the landscape function,the test choose high quality sewage as water resource for water quality standard.Researches are carried on to study the performance of the combination process of coagulative precipitation and constructed wetlands used to treat district reclaimed water.The main research content and conclusion are as follows:â‘ Carried on the orthogonal experiment influenced by the quantity of coagulation medicament to pretreat water and the operating mode parameters,and the results indicated:When original water quantity is COD=78～122mg/L,TP=1.1～4.5mg/L,and the mixing condition is G=80s^-1,t=6min,PAC=24mg/L and the PAM=0.075mg/L were added in sequence,the removal rate of COD and TP respectively achieved about 65% and 80%.â‘¡Carried on the constructed wetland design and the choice of wetland plant and the padding.The constructed wetland the water treatment start and the potency test research were also been done.The start test result indicated that,when the temperature is 20℃～33℃,and inflow water's COD is 180～200mg/L,and hydraulic load is 7.0cm/d,after start test lasted 30d,water leakage COD stably achieves 50～60mg/L; The tesr indicated:When the constructed wetland treat reclaimed water alone,hydraulic load respectively is 7.0,8.5,10.6,14.1 and 21.2cm/d,the change rule of COD,NH₃-N, TN and TP can be seen.â‘¢Used the coagulation precipitation and constructed wetland craft process to treat sewage.Through two kind of crafts different combinations operating mode and the temperature influence contrast experiment,it indicated that,the better operating mode of coagulation craft section is:Mix pond HRT=2min,PAC=24mg/L,the mixing speed is 120r/min,flocculation pond HRT=4min,PAM=0.075mg/L,the mixing speed is 30r/min;The better operating mode of constructed wetland craft section is:In summer (T=15℃),when the better load of constructed wetland is 21.2cm/d,the outflow water quanlity satisfied two standards simultaneously.In winter(T＜15℃),when the hydraulic load of constructed wetland is 14.1cm/d,the outflow can satisfy the first standard,but TN cannot achieve the latter standard;when the hydraulic load of constructed wetland is 10.6cm/d,the outflow water quanlity satisfied two standards simultaneously.It is an important way to enhance the non- traditional water source useage for district sewage treatment and reuse.Research on district reclaimed water reuse with the combination process of coagulative precipitation and constructed wetlands,which can highly adapt the undulation of water quality and volume,the plot,has openned the broader application prospect for water treatment and reuse of district and hotel and so on.It has important practical significance.