Study On Application Of The Immobilized EM Technology In The Constructed Wetland And Adsorption Characteristics Of Phosphorus Of Substrate

Constructed wetland is a very potential wastewater treatment technology. It has many advandtages, such as high treatment efficiency, low cost of construction, operation and maintenance, wide field of application and strong ability of shock loading resistance etc. As a new kind of applied wastewater treatment technology, researches on the application and development of constructed wetland have been paid more and more attention. Because of the pipeline network was not perfect and there were still some local urban sewage discharging into the river surface, the surface water pollution in many places became more and more serious in Foshan. Against the situation, the efficient, low-cost, aesthetic and healthy constructed wetland was mainly researched, in order to disperse the urban wastewater of Foshan in situ. It had been suggested local plants, EM and substrates would solve the problem. Buckets were adopted in simulated constructed wetland to study removed efficiency of the pollutions. Firstly, using 8 plants treated domestic wastewater. Secondly, some augmentation technologies were used to improve the purification efficiency of artificial wastewater treatment. Thirdly, adsorption isotherm and kinetics experiments were carried out to determine the effects of initial concentration on aqueous phase adsorption of phosphate, particle size and concentration of potsherd particles as a wetland construction material. The results are as follows:1. Containing of COD_cr600mg/L, NH₄⁺-N23mg/L, TP26mg/L in domestic wastewater, on the basis of the test on treating capability, the purification benefits of 8 plant species in south of China were evaluated comprehensively. The evaluated items included biomass, root, landscape, purification capacity, etc. The result is that the ceriman is better than others.2. Containing of COD_cr510 mg/L, NH₄⁺-N35mg/L, TP4mg/L in artificial wastewater, it was not significant that the immobilized microorganism was applied to the constructed wetland for improving the purification efficiency because COD_cr of EM was 30000～40000mg/L. However, the purification efficiency could be enhanced significantly in NH₄⁺-N-removal and P-removal if EM was applied properly in the constructed wetland (P＜0.05). The results indicated that purification capacity of EM, purification efficiency of NH₄⁺-N and TP was increased with increasing times. It suggested purification capacity of EM increase when superiority microorganisms were formed in the new environment. Substrates were significant in COD_cr, NH₄⁺-N and TP removal(P＜0.01).3. The results indicated that potsherd particles have regenerate capacity because it was not only excellent adsorption, but also excellent desorption in adsorption and kinetics experiments of substrates. When particle size was 0.5～1.0 mm and concentration of potsherd was 5.00g/100ml, lower quantity and higher P-removal efficiency would be gained in constructed wetland. The adsorption isotherm datas were well represented by the Langmuir isotherm model with the maximum adsorption capacity of 3.50mg/g. Adsorption isotherm was described as C_e╱q_e=10.164+0.2854C_e by Langmuir equation. Elovich equation was useful since it fitted the adsorption rate datas better than diffusion equation and the first order kinetics that calculated q_e was a good estimate of the equilibrinm isotherm capacity. Elovich equation described the adsorption rate datas as:1) Initial concentrationsofphosphate C₀=5mg/L, q=0.016lnt-0.032, r=0.987;2) Initial concentrations of phosphate C₀=10mg/L, q=0.033lnt-0.080, r=0.986;3) Initial concentrations of phosphate C₀=20mg/L, q=0.048lnt-0.111, r=0.982;4) Initial concentrations of phosphate C₀=80mg/L, q=0.254lnt-0.891, r=0.971.