【作者】 李剑波；

【导师】 周琪；

【作者基本信息】 同济大学 ， 环境工程， 2008， 博士

【摘要】 针对垂直流-水平流（vertical flow-horizontal flow,简称VF-HF）组合人工湿地系统普遍存在脱氮能力季节性差异和HF段反硝化碳源不足等问题,本研究通过在VF段填充一定量沸石基质,构建离子交换-生物再生强化组合人工湿地系统（enhanced vertical flow-horizontal flow hybrid constructed wetland,简称VF2-HF2）,暖季和寒季,实现微生物与沸石基质协同脱氮,并以曲阳污水处理厂初沉池出水为试验用水,与VF段填充砾石构建的组合人工湿地系统（verticalflow-horizontal flow hybrid constructed wetland,简称VF1-HF1）进行了COD、NH₄⁺-N、TN和TP处理效果比较研究。同时,开展了沸石生物再生动力学和水生植物枯叶强化HF段反硝化的动力学小试试验研究。当水力停留时间为4.4～17.6d,进水COD 120～300 mg·L^-1、氨氮12～33 mg·L^-1、总氮24～42 mg·L^-1和总磷2.8～9.4 mg·L^-1时,VF1-HF1组合湿地系统全年的去除率分别为64%～94%、4%～72%、3%～71%和15%～98%,而VF2-HF2组合湿地系统全年的去除率分别为82%～99%、52%～98%、34%～91%和20%～98%。当HRT≥4.4d,VF2-HF2组合湿地系统出水COD、氨氮、总氮和总磷全年可稳定达到《城镇污水处理厂污染物排放标准》（GB18918-2002）规定的一级B标准。如以出水水质达到GB18918-2002规定的一级B为主要目标,综合考虑处理水量和沸石生物再生要求,推荐VF1-HF1组合湿地系统采用HRT=17.6d,VF2-HF2组合湿地系统采用HRT=8.8d运行较为合适。基质类型对COD去除效果无显著影响,有机物的降解主要是通过厌氧菌和好氧菌的生物作用实现的,基质主要作为微生物附着的载体;菖蒲和水葱组成的多植物系统具有较发达的根系,能为微生物的附着生长提供更多的表面积,同时对有机物也具有较高的吸收能力,因此对COD的去除能力要优于单一的芦苇植物系统。对全年脱氮途径的分析和计算结果表明,生物脱氮占69%,是VF2-HF2人工湿地主要的脱氮形式,沸石吸附仅占16%,证明暖季沸石的吸附能力可以实现生物再生;对全年磷去除途径计算和分析可知,VF2-HF2组合人工湿地系统除磷作用主要发生在VF段,基质的吸附和沉淀作用是除磷的主要途径,占除磷总量的84%,植物收割仅占4%,证实植物收割除磷对高负荷污水处理的作用是有限的。沸石生物再生小试试验结果表明,沸石对氨氮的吸附和离子交换作用主要在2d内完成,沸石对NH₄⁺的饱和吸附量为3.32mgN·g^-1;阳离子浓度、曝气、硝化细菌和异养菌对饱和沸石再生效率的影响均可用一级动力学方程(y=1-e^-kt)模拟,曝气吹脱作用可使再生效率在再生液阳离子自然再生基础上提高1.5%,异养菌的存在可使再生效率提高7.7%,硝化细菌的存在可使再生效率提高48.9%。异养菌与硝化细菌共存时,再生时间超过80d时,硝化细菌和异养菌的生长存在底物抑制。通过对沸石再生前后沸石中的主要阳离子浓度(K⁺、Na⁺、Ca²⁺和Mg²⁺)测定可知,K⁺和Na⁺在沸石氨氮再生过程中起主要作用,这与四种离子与氨氮的分离因数测定结果相一致。植物枯叶释放有机碳源强化HF段反硝化是可行的。香蒲枯叶在投加后7～11d内反硝化速率最快,植物生长可将反硝化动力学常数k提高0.72倍,香蒲枯叶的投加可将反硝化动力学常数k提高3.56倍,香蒲枯叶经预处理后可将反硝化动力学常数k提高10.35倍;香蒲枯叶经碱洗预处理后,氨氮的释放速率和释放量随之增加,易降解含氮有机物在植物枯叶投加后10 d内分解较快,难降解有机氮化合物在在植物枯叶投加后17 d,可在酶催化剂作用下水解。PCR-DGGE分析结果表明,香蒲枯叶的投加和植物的生长都使反应器中的Shannon-Wiener指数发生一定变化。对DGGE结果进行测序分析和比对结果表明,反应器内主要存在的反硝化菌为Leptolyngbya属和Escherichia属,其相似性都达到了99%。更多还原

【Abstract】 In this research,enhanced hybrid constructed wetland system of vertical-flow （VF）and horizontal-flow（HF）using a zeolite,clinoptilolite in the vertical-flow constructed wetland（VF2-HF2）was designed,to chemically store ammonia in cold temperatures and regenerate biologically the ammonia adsorped under the conditions that are more conducive for nitrification,to solute poor nitrogen removal in colder climates.The other hybrid constructed wetland system of vertical-flow and horizontal-flow（VF1-HF1）filled with gravel instead of zeolite in VF was also designed,to find out the removal difference in COD,NH₄⁺-N,TN and TP between the two systems.As well,the kinetics of zeolite biological regeneration and enhanced denitrification by harvested leaves of hydrophyte in the horizontal-flow was investigated in the laboratory research.When hydraulic retention time（HRT）was 4.4～17.6d,with COD 120～300 mg·L-1,NH₄⁺-N 12～33 mg·L-1,TN 24～42 mg·L-1,TP 2.8～9.4 mg·L-1 in the influent,the removal efficiency of COD,NH₄⁺-N,TN and TP was 64%～94%,4%～72%,3%～71%,15%～98%in VF1-HF1,and was 82%～99%,52%～98%,34%～91%,20%～98%in VF2-HF2.When HRT is above 4.4d,the concentration of COD, NH₄⁺-N,TN and TP in the effluent of VF2-HF2 can steadily comply to the standard of I level-B of discharge standard of pollutants for municipal wastewater treatment plant（GB18918-2002）.Therefore,when the effluent should comply to the standard of I level-B of GB18918-2002,and treatment ability and zeolite biological regeneration are considered,it is advised to operate with HRT=17.6d for VF1-HF1,with HRT=8.8d for VF2-HF2.The main mechanism responsible for organic matter removal is the microbial activity of aerobic and anaerobic bacteria,the types of substrate have no significant influence on the degradation of COD,which mainly act as the carrier of microorganism growth.The iris and bulrush have a more vigorous root system,and provide an expanded surface area for attached microbial growth and additional nutrient uptake.Therefore,they have an higher removal efficiency of COD than reed. HRT has the significant influence on the removal efficiency of NH₄⁺-N in spring, summer and autumn,that of TN and TP in spring,summer and winter.There was a very strong positive correlation between influent load and removal rate of NH₄⁺-N, TN and TP.The removal path of nitrogen shows that biological removal accounts for 69%;the adsorption of zeolite accounts for just 16%,which proves the happen of biological regeneration of zeolite in warm climates.The removal path of phosphorus shows that the removal of phosphorus is mainly happened in VF1,substrate adsorption accounts for 84%,plant absorption just accounts for 4%,which is proved that the removal of phosphorus in high load wastewater treatment by plant harvest is limited.The result of zeolite biological regeneration showed that ion-exchange of NH₄⁺-N mainly happened in two days,the saturated adsorption capability of zeolite is 3.32mgN·g^-1.The influence of cation concentration,aeration,nitrifying bacteria and heterotrophic bacteria on the regeneration efficiency fits the fist order kinetic reaction. The regeneration efficiency can be raised by 1.5%with aeration on the basis of regeneration of cation concentration,7.7%with heterotrophic bacteria,and 48.9% with nitrifying bacteria.When heterotrophic bacteria and nitrifying bacteria coexisted in a reactor,the functions of nitrifying bacteria and heterotrophic bacteria were inhibited by substrate competition when the regeneration times were above 80d.The determination of cation concentration before and after zeolite biological regeneration showed that K⁺ and Na⁺ took an important role in the biological regeneration,which is consistent with the separation factor between NH₄⁺-N and other cation.It is feasible that harvested plants are used to supply carbon source for denitrification in HF reactor,the rate of denitrification is the fastest after 7～11d added of harvested cattail.The denitrification kinetic constant can be raised by 0.72 times because of the growth of live reed plant,3.56 times because of the addition of the leaves of dead cattail,10.35 times because of the addition of harvested cattail after pretreatment.The rate of NH₄⁺-N released goes up after the harvested cattail pre-treated by NaOH alkali solution.The result of PCR-DGGE shows that the Shannon-Wiener changes with the addition of harvested cattail and the growth of standing reed plant.The result of DGGE shows that the main bacteria existed in the reactor are Leptolyngbya and Escherichia with the similarity of 99%.更多还原