| With the rapid economic development recent years, the growing requirements ofthe environmental quality, the urban sewage and industrial waste water has beengradually solving now, while rural and small towns sewage pollution problem becomemore imperative. Because of our country economy develops, the towns can’t laidsewage pipe network and collect sewage treatment like city, therefore, using theecological engineering technique to sewage purifying and get rid of the nutrient,which can reduce water pollution around towns, improving water environment andensuring water safety with great significance. Based less developed towns sewagetreatment problem in yangtze-huaihe region, study on sewage removal efficiency ofnutrient by building the sewage septic tank-land treatment system combinationtechnique. Focus on land treatment system of phosphorus purifying effect and surfacesoil phosphorus combined forms and migration transformation process. Study on landtreatment system of phosphorus purifying effect and surface soil phosphoruscombined forms and migration transformation process, based on sewage high levelsof the water quality SRP characteristics. At the same time, study on rice huskactivated carbon eco-agricultural of phosphorus adsorption, solve the problem oftraditional packing easy saturated, the main research contents and achievements are asfollows:(1) The physical and chemical indexes of the two land treatment system during operation, the average temperature was26.1℃, pH was7.29, DO was1.38mg/L,ORP was51.4mv and SS was118mg/L. Index of COD and TN, the artificial wetlandand the surface filtration system had higher COD removal rate of82.9%and64%respectively, the removal rate of TN was34.1%and28.9%respectively, Both of thetow systems had good removal efficiency on total phosphorus of sewage, the removalrate was61.6%and48.2%respectively, and the percentage of PP in total phosphoruscontent was low, most group of TP was SRP, which easily to be absorbed by the plantutilization.(2) Spatial and vertical variation of total phosphorus (TP) concentration wasbetween149.2-159.4mg/kg. The consideration of phosphorus forms, the main formsof phosphorus of surface soil was Ca-P, which accounted for33.1%of TP, followed inorder by Ex-P, Org-P, Fe-P and Oc-P, which accounted26.1%,19.6%,14.2%and7%of TP respectively. The consideration of Bio-available phosphorus (the sum of Ex-Pand Fe-P), which accounted larger percentage of TP, increased from38.0%to40.3%.Inert phosphorus (Oc-P, Ca-P and Org-P) may be converted to Bio-availablephosphorus. Mineralization of Org-P rate was greater than the cumulative rate bymicrobial. The correlation analysis showed that concentration of different formsphosphorus and pH is irrelevant except Ca-P. Org-P had response relation betweenthree other forms of phosphorus (Ex-P, Ca-P and Fe-P).(3) Rice husk activated carbon with rich microporous, mesoporous was madefrom agricultural waste rice husk by carbonization, activation, pickling, washing,drying process.BET specific surface area reached886.3m2/g. The adsorptionphosphorus conditions of rice husk activated carbon were optimized by orthogonaltest, and isothermal adsorption, adsorption kinetics were investigative simultaneously.The results indicated that the adsorption isotherm of phosphorus better met theLangmuir model and Freundlich model, the correlation coefficient R~2＞0.92; Ricehusk activated carbon adsorption capacity for phosphorus reached6.93mg/g, by theLangmuir linear regression equation; Rice husk activated carbon adsorption process for phosphorus can be described with a pseudo second-order kinetic equation, thecorrelation coefficient R~2=0.9968. Adsorption process at a faster pace, theproliferation phase of the particle adsorption rate control stage. Rice husk activatedcarbon has good prospects as a readily available, inexpensive, and efficient matrixfilling, in rural decentralized sewage ecological treatment technologies. |
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