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生态塘—湿地耦合系统处理上海崇明地表水研究

Study on Eco-pond & Wetland Coupled System Deal with Surface Water in Chongming of Shanghai

【作者】 季兵

【导师】 陈季华;

【作者基本信息】 东华大学 , 环境科学与工程, 2010, 博士

【摘要】 主要研究内容有:(1)建立生态塘-垂直流湿地和生态塘-水平流湿地小试装置净化中心河水的效能研究(2)考察水力负荷、溶解氧和温度对污染物去除能力的影响及污染物的沿程变化。(2)从基质、高等植物、低等植物角度研究中心河水中氮磷在系统中的迁移转化规律。(3)建立中试工程研究整个系统去除污染物的效能和主要单元生态纤维塘、潜流式湿地去除污染物的机理,对整个系统的贡献,营养元素输移规律。(4)拟合污染物在无植物系统、浮萍系统、金鱼藻系统去除动力学模型并进行参数研究。(5)对系统进行环境效益、生态效益、经济效益和社会效益的评价,研究提高系统去除污染物能力的途径。主要创新点:(1)针对崇明前卫村的高浊度表征地表水,进行氮、磷元素高效去除污染控制技术及机理的深化研究。(2)污染物质在生态净化系统中的迁移转化一直用“灰箱”理论加以描述,本论文通过实验对污染物质具体的迁移过程和转化途径进行深入的研究和探讨,揭示生态塘-湿地耦合系统中氮磷的存在形式及转化方式,从基质、高等植物和低等植物等角度对氮磷的吸收吸附的进行实验,为塘.湿地系统的脱氮除磷提供理论依据。(3)在中试系统氧化塘中采用东华大学自主研发的聚酯纤维弹性填料模拟自然水草,微生物在纤维丝上附着生长,强化塘对水中浊度去除,并前置于人工湿地前解决目前潜流式湿地普遍存在的堵塞问题。(4)采用河道疏竣底泥作为原料,烧制多孔生态轻质陶粒,应用于崇明的水体生态修复,研究其在氮磷去除方面的功效和吸附释放平衡。主要研究结论如下:(1)小试系统对浊度变化有很强的适应性。随着水力负荷的降低,系统对浊度的去除率呈曲线型升高,在水力负荷条件达到0.015 m3/(m2.h)前,水力负荷的降低与去除率的升高呈线性关系,水力负荷达到0.015 m3/(m2.h)后,随着水力负荷的降低,去除率升高不明显,趋向平缓。确定水力负荷在0.015 m3/(m2.h)为宜。低水力负荷水力条件下,对总氮的处理效果明显优于高负荷水力条件。对于总磷的去除,进水总磷浓度相近的情况下,高负荷水力条件处理效果稍好一些。(2)采用y=A*eBx指数方程拟合温度与COD去除速率效果最佳,生态塘一水平流湿地COD去除速率与温度的拟合方程为y=10.58exp(0.0344x)R2=0.6028;生态塘—水平流湿地COD去除速率与温度的拟合方程为y=10.59233exp(0.03662x)R2=0.75。两塘温度与COD去除速率之间均呈正相关的关系,在相同温度条件下垂直流复合系统明显高于水平流。总氮去除速率极差垂直流大于水平流,垂直流人工湿地系统总氮去除速率受温度影响较大。总氮去除速率不仅与氨氮相关,还会受到物理、化学和生物等诸多过程共同影响。两系统总磷去除速率的相伴概率皆为0.000,相关性在α为0.01显著。两系统温度与总磷去除速率的拟合采用Sigmoidal方程。两系统总磷去除速率的极差相近,去除速率受温度影响差异不大,总磷的去除主要取决于填料的物理吸附作用。(3)塘区单元内沿深度方向的DO变化情况所配合的回归方程为y=A×exp(B*x),塘—垂直流湿地系统A=5.409,B=-0.032,R2=0.9937;塘—水平流湿地系统,A=6.053,B=-0.036,R2=0.9880。显著性检验均非常明显。在沿着水流方向,塘—水平流湿地生态系统的DO表现出很好的相关性。所配合的回归方程为y=ax2+bx+c,求得a=-0.002379,b=0.2386,c=4.07,R2=0.9599,线性相关性显著。微生物和植物呼吸作用耗氧速率与植物的光合作用产氧速率以及大气复氧速率基本保持动态平衡。(4)对浊度、氨氮去除生态塘-垂直流湿地出水效果优于生态塘—水平流湿地。生态塘是NH4+-N去除的主要单元,平均占到总去除率的75%~90%,后续湿地系统主要滤去处理水中的藻类和截留大部分的悬浮物,利用植物根系和陶粒的吸附、截留作用对出水氨氮再做进一步处理。两系统对TP的去除率分别在19%~54%和14%~45%之间,塘-垂直流系统对TP去除稍高于塘—水平流系统。湿地填料对总磷去除存在一个动态平衡,4~6小时解吸附的速率下降,6h以后陶粒对磷的解吸量呈现缓慢上升,0.2mg/L析出与吸附达到动态平衡。塘-垂直潜流湿地系统的CODcr去除率要好于塘-水平潜流湿地系统。生态塘中去除率最高可达28%,是CODcr的主要去除单元。(5)系统中脱氮途径对除氮的贡献依次为微生物代谢(硝化反硝化及微生物吸收)、基质吸附、湿地植物地上生物量吸收、塘内藻类吸收。系统中除磷途径对除氮的贡献依次为基质吸附、植物地上生物量吸收、塘内藻类吸收。陶粒的吸附是湿地除磷的最主要的形式,植物也起到重要作用。(6)石灰石与陶粒对氮都有吸附作用,而且两种基质随着污染物浓度升高,吸附量也有所增高,但到一定程度增长速率有下降趋势,石灰石吸附量在总氮浓度21.5mg/L的条件下,达到最大值,随着总氮浓度的增加,吸附量基本维持稳定。对于总氮的吸附量,陶粒的吸附能力要强于石灰石,在总氮浓度为19mg/L条件下,达到吸附平衡,石灰石的吸附量为0.089mg/g,而陶粒的吸附量为0.228mg/g,约为石灰石吸附量的2.56倍。选择陶粒作为填料更有利于总氮的去除。(7)石灰石和陶粒对磷都具有吸附作用,陶粒吸附磷的作用要强于石灰石。在1.8mg/L总磷污水中,达到平衡时,石灰石对于TP的吸附量为0.1mg/g,陶粒的吸附量为0.15mg/g,约为石灰石吸附量的1.5倍。随着污染物浓度的增加,两种基质吸附量都有所增加,但是陶粒增加速度更快,在含0.6mg/L总磷的污水中,达到平衡时,而石灰石的吸附量为0.24mg/g,陶粒的吸附量为0.38mg/g,约是石灰石吸附量的1.6倍。对于吸附磷而言,基质应该选择陶粒为佳。相同条件下,陶粒对总磷吸附量为石灰石的1.5倍以上,总氮吸附量为2.5倍以上,而且陶粒多孔,比表面积大易于微生物附着,形成生物膜。但综合考虑起来,石灰石取用方便,而且石灰石的使用加大了厌氧层的厚度,有利于总氮和其他污染物的去除,同时石灰石可以调节水体的pH值,使微生物生活的环境更加稳定,有利于微生物生长,所以采用底层陶粒,中间层用石灰石。(8)植物对氮磷的转移量与植物量呈现正相关,与装置类型和种植面积关系不大。植物对氮磷的吸收量变化不大,吸收量很少,通过收割不能够大幅度提高装置的脱氮除磷效率,但应该采取适当收割,去除腐败植物的方式来处理湿地中植物。(9)研究藻类对氮素的吸收作用。TN进水浓度基本在1.6mg/L左右,出水浓度保持在1.2mg/L左右,而去除率却随着时间的延长逐渐变低,由开始的35%降到最后基本维持在20%左右,靠藻类对于氮素的吸收不能够满足处理要求。TP进水浓度在0.12-0.17mg/L范围内徘徊,出水也保持在0.07-0.11m/L之间,处理效果不是很理想。单纯利用藻类对于氮磷的吸收来处理河水,效果并不理想。在氮去除作用中,随着时间的延长,处理效果逐渐下降;而在磷去除作用中,去除率很不稳定,出水总磷浓度随进水变化很大,再考虑到水体中磷的含量与浊度的关系和实验中悬浮物的沉淀,从而反应藻类对磷的去除效果也并不明显。(10)建立的中试系统高效生态纤维塘/潜流式人工湿地对CODcr、TN、TP、浊度的平均去除率分别为48.4%、45.3%、65.38%、94.89%;最终出水指标达到或接近设计要求,能满足农村景观水的需要。系统中有机污染物主要依靠微生物代谢,氮的去除主要依靠微生物硝化与反硝化,总磷主要通过基质吸附沉淀去除,浊度主要通过自然沉降、生态纤维膜和填料表面生物膜的吸附而去除。(11)陶粒填料的表层覆盖20厘米平均粒径在3~5厘米的碎石,主要为石灰石,从某种意义上将厌氧层增厚了20cm,延长了厌氧层的水力停留时间,有更多的有机物在厌氧层被消耗,降解同样质量的有机物厌氧微生物的产泥量远小于好氧微生物;表层碎石的粒径变大后吸附效果降低,污泥不易在表层沉积;石灰石还能改善底部厌氧微生物产酸发酵形成的酸性水质,为表层好氧微生物创造更好的环境条件,有利于CODcr的去除。(12)前置生态纤维塘能有效去除悬浮污染物,改善崇明地表水进水高浊度的状况。降低湿地的负荷,解决目前湿地普遍存在的堵塞问题。前置氧化塘中人工水草是采用东华大学自主研发的聚酯纤维弹性填料,由弹性丝、中心件和中心绳组成,其中弹性丝用于粘附生物膜,填料在水中悬浮,弹性填料垂直悬挂,进水中的悬浮颗粒与弹性填料碰撞后速度减小,进而沉降至氧化塘底部,和潜流式人工湿地相比,可以设置排泥管,这是生态纤维塘作为悬浮物主要去除单元不可替代的优势,(13)无植物、浮萍、金鱼藻系统对NH3-N、TP、PO43--P、CODcr去除符合一级反应动力学。处理能力为:金鱼藻系统>浮萍系统>无植物系统。无植物、浮萍、金鱼藻系统NH3-N去除速率系数分别为0.0372d-1、0.1071d-1和0.1534d-1,TP去除速率系数为0.0061d-1、0.0097 d-1和0.0234d-1,PO43--P去除速率系数为0.0036d-1、0.0108d-1和0.0364d-1,CODcr去除速率系数为0.0046 d-1、0.064 d-1和0.074d-1。(14)该项目研究开发的污水资源化处理技术,不仅具有较高的实用价值,同时还具有明显的环境效益、社会效益和经济效益。

【Abstract】 This research comed from the major scientific and technological project of Shanghai Science and Technology Commission," The evolution of the law of the domain of water environment and water quality improvement technology research in Chongming Island,"(Number:06DZ12307),and received a Ph.D.thesis Innovation Project funding(Number:113-06-0019027) of Donghua University.River water of Qian Wei village,Chongming as the object of study,carried out the eco-pond& wetland coupled system of its purification and mechanism performance,process experiments. Main research contents:(1) Establish small pilot plant of ecological pond-vertical-flow wetland and ecological pond- horizontal flow wetlands for water purification performance study.(2) Study the hydraulic loading,dissolved oxygen and temperature on the pollutant removal ability of pollutants along the way influence and change.(2) From the matrix,higher plants,lower plants research nitrogen and phosphorus in center river water in the system of migration and transformation rules. (3) Establish pilot projects to look at the whole system pollutants removal performance from the main unit of eco-fiber pond,subsurface flow constructed wetlands and pollutants-type removal mechanism,the contribution of the whole system,nutrients transport in the law.(4) Fit of pollutants in non-plant systems, duckweed system,hornwort system removing dynamics model and Study parameter. (5) Evaluate environmental efficiency,ecological benefits,economic and social benefits of Systems and research way to improve system capability of removing contaminants.Major innovations points:(1) Deepening research on characterization of high turbidity of surface water in Qian Wei village of Chongming for nitrogen and phosphorus pollution control the suspended solids retention,use of plant roots and ceramic The adsorption of ammonia-nitrogen retention role of the water do further processing.These two system TP removal rates was form 19%to 54%and 14%to 45%respectively,and the pond -vertical-flow system for TP removal slightly higher than the pond- the level of flow system.Filling of wetlands on the existence of a dynamic balance of total phosphorus removal,4~6 hours decreased the rate of desorption,6h after the desorption of phosphate ceramic volume rendering rise slowly,0.2mg/L precipitation and adsorption to achieve dynamic balance.Pond- vertical subsurface flow constructed wetland system CODcr removal better than pond- the level of subsurface flow constructed wetland system.The removal rate of Eco-pond was up to 28%,it was the main removal CODcr unit.(5)The contribution of nitrogen removal in system was followed by microbial metabolism(nitrification,denitrification and microbial uptake),matrix adsorption,the aboveground biomass of wetland plants to absorb,Tong absorbed within the algae. The contribution of phosphorus removal in system was followed by substrate adsorption,absorption of the aboveground biomass of plants,pond algae absorbed within.Ceramic adsorption was the most important wetlands in the form of phosphorus,plants also played an important role.(6) Limestone and ceramic adsorbed nitrogen,and the two kinds of substrate with the concentration of pollutants,adsorption capacity has also been increased,but the growth rate to a certain extent there was a downward trend in total nitrogen concentration in the adsorption capacity of limestone 21.5 mg/L under the conditions to achieve maximum value,with the total nitrogen concentration increases,adsorption basically remained stable.For the total nitrogen adsorption capacity,adsorption capacity of better than ceramic limestone,in the total nitrogen concentration of 19mg /L under the conditions to reach adsorption equilibrium,the adsorption capacity of limestone 0.089mg/g,while the adsorption capacity of ceramsite 0.228mg/g,about 2.56 times the adsorption capacity of limestone.Select ceramic as a filler more conducive to the removal of total nitrogen.(7)Limestone and ceramic had a good role in adsorption of phosphorus,ceramic limestone stronger than the role of adsorption of phosphorus.In the 1.8mg/L total phosphorus effluent to reach equilibrium,the adsorption capacity of limestone for the TP to 0.1mg/g,the adsorption capacity of ceramic 0.15mg/g,about 1.5 times the adsorption capacity of limestone.With the increase in pollutant concentration,two kinds of substrate adsorption capacity has increased,but the ceramic to increase faster, containing 0.6mg/L of total phosphorus in wastewater,to achieve equilibrium,while the adsorption capacity of limestone 0.24mg/g,the adsorption capacity of ceramic 0.38mg/g,the adsorption capacity of limestone is about 1.6 times.For the adsorption of phosphorus,the matrix should choose ceramic better.Under the same conditions, ceramic limestone on the phosphorus sorption capacity of more than 1.5 times,total nitrogen adsorption capacity of more than 2.5 times,and the ceramic porous,large surface area and ease of microbial attachment to form a biofilm.But taken together, limestone and access to convenient,and the use of limestone increased the anaerobic layer thickness is conducive to the removal of nitrogen and other pollutants,while limestone can adjust the pH value of water,so that micro-organisms living environment more stability is conducive to microbial growth,so use of the bottom of ceramic,the middle layer of limestone.(8) The transfer of plants to the amount of N and P showed a positive correlation with plant capacity,and device type,and little to do with acreage.N and P uptake by plants changed little,very little absorption through the harvest can not be greatly improved devices,nitrogen and phosphorus removal efficiency,but should take appropriate harvesting of plants to remove corruption and the way to deal with wetland plants.(9) Study the role of algae on the absorption of nitrogen.Basically,the influent TN concentration of 1.6mg/L or so,the effluent concentrations maintained at 1.2mg/L, while the removal rate has gradually changed with time low,down 35%from the start of the last remaining at around 20%and rely on algae for the absorption of nitrogenwas no able to meet the processing requirements.TP influent concentration in 0.12-0.17mg/L,within the scope of wandering,the effluent was also maintained at 0.07-0.11mg/L,between the treatment effect was not very satisfactory.Simple use of algae for the absorption of nitrogen and phosphorus to deal with the water,the effect was not satisfactory.Role in nitrogen removal,with the extension of time to deal with effects of a gradual decline;while in the role of phosphorus removal,the removal rate was very unstable,the effluent total phosphorus concentration changed dramatically with the water,and then taking into account the phosphorus in water The content and the relationship between turbidity and suspended solids in the sedimentation experiment,thus reflecting the effects of algae to phosphorus removalwas also not obvious.(10) Establish a pilot engineering system,CODcr,TN,TP,turbidity,the average removal rates in high-efficiency ecological fiber Pool/ Subsurface Flow Constructed wetlands were 48.4%,45.3%,65.38%and 94.89%.The final effluent indicators had reached or close to design requirements,to meet the water needs of the rural landscape.System mainly depend on microbial metabolism of organic pollutants, nitrogen removal mainly depend on microbial nitrification and denitrification, phosphorus removal,mainly through substrate adsorption precipitation,turbidity, mainly through natural sedimentation,eco-fiber membrane and filler surface adsorption and biofilm removed.(11) Covering the surface of ceramic filler average particle size of 20 cm in the 3~5 cm of gravel,mainly limestone,in a sense to the anaerobic layer thickness of 20cm, the extension of the anaerobic layer of hydraulic retention time there were more layers of organic material was consumed in the anaerobic degradation of the same quality of soil organic matter anaerobic microbial production capacity is far less than the aerobic microorganisms;the size of gravel surface after the adsorption of larger reduction in the surface sludge was not easy deposition;limestone also improves the bottom of the anaerobic microbial fermentation of the formation of acid acidic water,as the surface of aerobic micro-organisms to create better environmental conditions conducive to the removal of CODcr.(12) Pre-eco-fiber pond could effectively remove suspended pollutants,improving water Chongming high turbidity of surface water conditions.To reduce the load on the wetlands to resolve the current widespread obstruction of the wetlands. Pre-oxidation pond and artificial grass was used self-developed polyester elastic filler by Dong Hwa University,from flexible wire,center pieces and central rope, composed of spandex for the adhesion of biofilm,fillers suspended in water,the vertical elastic filler suspension,water of suspended particles after the collision speed and flexibility of filler decreases,thus settling to the bottom of the oxidation pond, and subsurface flow constructed wetland in comparison,you can set the mud tubes, which was eco-fiber pond as the suspended solids removal unit main irreplaceable advantages,(13) NH3-N,TP,PO43- P,CODcr removal in No plant,Lemna minor,Ceratophyllum demersum system were line with a reaction kinetics.Processing capacity as follows: Ceratophyllum demersum systems,duckweed system,no plant system.NH3-N removal rate of No plants,Lemna minor,Ceratophyllum demersum system coefficients were 0.0372d-1,0.1071d-1 and 0.1534d-1,TP removal rate coefficient were 0.0061d-1,0.0097d-1,and 0.0234d-1,PO43- P removal rate coefficient were 0.0036d-1, 0.0108d-1 and 0.0364d-1,CODcr removal rate coefficient were 0.0046 d-1,0.064 d-1 and 0.074d-1.(14) Research and development of wastewater treatment technology on this project not only had high practical value,but also had obvious environmental benefits,social benefits and economic benefits.

  • 【网络出版投稿人】 东华大学
  • 【网络出版年期】2010年 08期
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