【作者】 郭一明；

【导师】 刘云国；

【作者基本信息】 湖南大学 ， 环境科学与工程， 2014， 博士

【摘要】 本研究以设计一种可推广的分散式生活污水深度生态处理技术为目标,以耦合Sequencing Batch Biofilm Reactor (SBBR)及Vertical Flow Constructed Wetlands (VFCW)技术为基础设计了SBBR-VFCW装置。在SBBR-VFCW基础上,以恢复和维持农村塘、池水体生态健康为目标,设计了促生态恢复型集成式生态浮床(Restoration-Promoting Integrated Floating Bed, RPIFB)。实验以SBBR-VFCW为核心处理技术,以RPIFB为农村水体生态系统的保育技术,为农村分散式生活污水深度处理及水体生态环境健康维护提供了一套新的技术方案。具体内容包括：(1)研究通过设计有效容积为18L、工作容积为12.5L的SBBR反应器,处理了TN、TP、NH4+-N、CODCr浓度范围分别为87.0-100.0mg/L、6.0-8.0mg/L、75.0-85.0mg/L、490.0-510.0mg/L的高浓度和64.0-75.0mg/L、4.0-6.0mg/L、55.0-64.0mg/L、360.0-380.0mg/L的中浓度模拟农村分散式生活污水(文中简称污水)。以12h为一个周期分两阶段共进行了20周期的污水处理实验。其中,前10周期进水负荷为7L,考察了SBBR系统对两种浓度污水的处理能力；后10周期,进水由7L/cycle,以0.5L/cycle的增长速率渐增至12.5L/cycle,考察了SBBR的耐负荷增长能力。结果显示：SBBR处理高浓度污水时出水中的TN、TP、 NH4+-N、CODcr达到《城镇污水处理厂污染物排放标准》(GB18918-2002,下称标准)I级A标准的频率分别为100%、0%、60%、20%,处理中浓度污水的出水达I级A标准的频率分别为100%、0%、100%、100%；II级标准限值下,SBBR处理高浓度污水进水负荷可增大至初负荷的,1.3-1.6倍,处理中浓度污水时可至1.7-1.8倍。因而,SBBR能较好的处理污水并耐污染负荷增长,随进水浓度降低其处理及耐负荷能力增强；但SBBR对污染物处理能力不均衡,TP处理能力较弱；出水虽能满足农田灌溉等再生利用标准,但仍具较强致富营养化性。SBBR宜作为耦合工艺的第一环节技术,采取有效技术补充深化污染物的处理。(2)研究通过设计体积80L、有效容积为25.2L的VFCW系统,以美人蕉为功能植物,布置卵石、天然沸石、土壤基质,处理了TN、TP、NH4--N、CODcr浓度范围分别为59.0-62.0mg/L、4.2-5.0mg/L、45.0-50.0mg/L、290.0-310.0mg/L的中浓度和32.0-35.0mg/L、1.4-1.7mg/L、28.0-30.0mg/L、61.0-65.0mg/L的低浓度模拟污水,两种浓度下以0.10m3/m2·d和0.17m3/m2·d两种负荷测试了VFCW对污染物的处理率及沸石基质孔隙率的变化。VFCW系统在中浓度污水0.10m3/m2·d负荷入水情况下,出水各指标均未达GB18918-2002I级A标准,相同负荷条件下处理低浓度污水时各出水指标均达I级A标准；两浓度污水负荷由0.10m3/m2·d增至0.17m3/m2·d时,出水水质均下降明显；由VFCW系统沸石基质孔隙率、出水可再生利用性、富营养胁迫性的变化,发现高浓度、高水力负荷条件下VFCW孔隙率降低速率更快,出水可再生利用范围更窄,对受纳水体富营养化胁迫更强。因而,VFCW系统对进水水质要求较高,宜在通过前处理初步消减污染物,使入水污染物浓度有所降低的基础上发挥深度处理作用。(3)研究通过设计的耦合SBBR及VFCW两种工艺的一体化SBBR-VFCW装置,以3个SBBR-VFCW装置在不同DO、曝停比、干湿比、进水量条件下处理了高、中、低3个浓度(以TN、TP、NH4+-N、CODCR为指标)水平的模拟污水。取连续20d的出水水质数据作为BPN人工神经网络模型训练的样本,应用MATLAB软件,设置隐含层为7,学习速率为0.14,动量因子为0.6,学习时间为8000h对实验进行模拟。结果显示,3组SBBR-VFCW出水NH4+-N、TN、CODCr全部可以达到I级A标准,出水TP介于I级B标准与II级标准问；低浓度进水时TN、TP、NH4+-N、CODCr的去除率分别可达91.5%、88.5%、98.5%、97%。以随机抽取的6组测试样本对BPN模型的模拟能力检验,TN、TP、NH4+-N、CODcr的MAER值分别为6.6%、5.9%、7.2%、6.4%均低于13.5%,测试样本均方根误差(RMSE)均小于0.078,相关系数均大于0.99,证明BPN模型泛化能力和过程模拟能力良好。通过模型权重分析,可知SBBR-VFCW出水TN、TP、NH4+-N、 CODcr受进水NH4+-N、曝停比、DO影响明显。实验显示SBBR-VFCW对模拟农村生活污水处理能力好,出水可再生利用性强,对农村水环境富营养化胁迫小,BPN模型能较好的模拟SBBR-VFCW这一非线性多变量的耦合污水处理过程,为预测系统水质变化、在线监测、工艺自动控制提供了基础。(4)研究通过设计的促生态恢复型人工浮床(restoration-promoting integrated floating bed, RPIFB)为SBBR-VFCW系统的处理生活污水的出水的环境转归做了进一步深度净化补充技术的探索。RPIFB中,浮水床、沉水床以天然沸石为基质,为挺水植物(美人蕉,Canna indica Linn.)和沉水植物(菹草,Potamogeton crispus Linn.)着生提供了条件,RPIFB以网裹覆,内部放养铜锈环棱(Bellamya aeruginosa)、泥鳅(Misgurnus anguillicaudatus),所有组分为系统内部构成完整的生物链提供了基础。实验以富含蓝绿藻类和原生动物的富营养化池塘水为基础,添加KH2PO4、(NH2)2CO和NH4NO3营造重富营养化水体。实验1以CODCr、 NO3--N、NH4+-N、TN、TP、Chl.a、浊度等指标(其中TN、TP、NH4+-N、CODcr浓度值均大于SBBR-VFCW出水浓度)的变化对比了FB、GSB及RPIFB对水体的净化能力,研究了光照作用于GSB进而影响RPIFB净化功能的特点；实验2探究了RPIFB中美人蕉、菹草、泥鳅、铜锈环棱螺对沉水床光照和深度变化的生理响应,分析了RPIFB的生态保育能力。结果显示,PRIFB作用下TN、TP、NH4+-N、和CODcr的去除率分别可达74.5%±1.4%、98.3%±4.3%、74.7%±0.5%、88.8%±1.3%和71.4%±2.5%,Chl.a和水体浊度可降至初始浓度水平的10%,FB、GSB及RPIFB净水能力顺序为RPIFB>FB>GSB。RPIFB不但能对SBBR-VFCW的出水实施深度净化,预防并治理富营养化水体,还可促进沉水植物恢复至水体下垫面,促进水体生态系统发生藻型相态向草型相态的转变,为农村塘、池等水体环境的生态健康提供了思路。更多还原

【Abstract】 A coupling device SBBR-VFCW was constructed to remediate domestic wastewater with the characteristics of easier construction, lower operating cost, easy management, stable and reusable effluent, etc. In order to restore and maintain a healthy aquatic ecological environment, a Restoration-Promoting Integrated Floating Bed (RPIFB) system was designed. The SBBR-VFCW was used as the key feature in the sewage disposal systems. The RPIFB was utilized as supplement to the conservation of the rural aquatic environment. The coupled systems provide a new technical for the advanced treatment of the decentralized rural domestic wastewater and preservation of a healthy aquatic environment. Specific content includes:(1) A SBBR reactor was designed to purify the synthetic domestic wastewater (hereinafter referred to as wastewater) with high concentration (TN,87.0-100.0mg/L; TP,6.0-8.0mg/L; NH4+-N,75.0-85.0mg/L; CODCr490.0-510.0mg/L) and moderate concentration (TN,64.0-75.0mg/L; TP,4.0-6.0mg/L; NH4+-N,55.0-64.0mg/L; CODcr,360.0-380.0mg/L). The effective volume, working volume and the work cycle of the reactor were18L,12.5L and12h, respectively. To test the purification performance of SBBR, the inlet wastewater load of the first10cycles was set to7L. To test load resistant ability of SBBR, the inlet was added from7L/cycle to12.5L/cycle at the growth rate of0.5L/cycle in the posterior10cycles. Results showed that SBBR could effectively cope with high concentration wastewater. Effluent concentration achieves the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002)(level I class A; hereinafter referred to as the standard). The qualification rates of TN, TP, NH4+-N and CODcr were100%,0%,60%and20%respectively in high concentration experimental group,100%,0%,100%and100%in moderate concentration experimental group. To keep the effluent within level II of the standard, the influent wastewater load of the SBBR could be increased to1.3-1.6times of the initial when deal with the high concentration wastewater, and increased to1.7-1.8times when deal with the moderate concentration wastewater. Therefore, SBBR can deal with wastewater efficiently, and can anti to the growing pollution load. Its treatment and resistance capacity to load enhanced with the decrease of influent concentration. But the performance of SBBR on the pollutant is unbalanced, such as that TP removal efficiency is weak. Though the effluent of SBBR can meet Chinese standards for farmland irrigation and some other standards, it can still not avoid threating rural water environment to become eutrophication. SBBR can be taken as the first round of the coupling process, and effective technical supplement should be taken to improve the treatment.(2) A VFCW system (with volume of80.0L, effective volume of25.2L) was designed to deal with both moderate concentration wastewater (TN,59.0-62.0mg/L TP,4.2-5.0mg/L; NH4+-N,45.0-50.0mg/L; CODCr290.0-310.0mg/L) and low concentration wastewater (TN,32.0-35.0mg/L; TP,1.4-1.7mg/L, NH4+-N,28.0-30.0mg/L; CODcr,61.0-65.0mg/L). Canna indica Linn. was taken as the functional plant. Besides, pebbles, natural zeolite and soil were applied as the matrix bed. Changes in the purification rate and zeolite porosity were observed under two concentrations and two hydraulic loadings (0.1m3/m2·d and0.17m3/m2·d). Results showed that the effluent couldn’t meet the level I class A of the standard when purifying the moderate concentration inflow at the hydraulic loading0.1m3/m2·d. The effluent water quality decreased significantly when the hydraulic loading increased from0.10m3/m2·d to0.17m3/m2-d. According to the variation of zeolite matrix porosity, renewability of effluent and eutrophication stress over watery environment, the performance of VFCW decreased faster under high concentration and high hydraulic load. The effluent will also be reused in a narrower field, and the receiving water body eutrophication stress became stronger when VFCW work under extreme concentration and hydraulic load. Thus, VFCW requires high quality influent. It can play a role as advanced treatment after the pollutant concentration decreased in the first round.(3) A coupling device SBBR-VFCW was designed. Three SBBR-VFCW systems were applied to deal with wastewater at three different levels of concentrations and at different DO, exposure time, wet/dry ratio and the amount of influent conditions.20days data of the effluent were collected as the training samples of BPN model. The optimum operating parameters of this network were as follows:the hidden layer (n)=7, learning rate (LR)=0.14, momentum constant (MC)=0.6, learning time (LT)=8000. Results showed that all NH4+-N, TN and CODCr values of effluent of three SBBR-VFCW systems could reach the level I class A of the standard, except that the TP concentration could some time reach beyond level I class A of the standard. When concentrations of influent were low, the TN, TP, NH4+-N and CODCr removal rates reached up to91.5%,88.5%,98.5%and97.0%, respectively.6groups of test samples were chosen at random to test the simulation performance of BPN models. MAER values of TN, TP, NH4+-N and CODCr were6.6%,5.9%,7.2%and6.4%, respectively, all lower than13.5%. The root mean squared errors (RMSE) were lower than0.078, and the correlation coefficients (R2) all higher than0.99, which proved that BPN can efficiently reflect the nonlinear function. And ANN is suitable for the dynamic monitor of the performance of SBBR-VFCW in various conditions. Through the weights analysis, TN, TP, NH4+-N and CODCr of effluent in SBBR-VFCW were affected significantly by NH4;+-N, aeration/non-aeration ratio and DO of influent. Thus, SBBR-VFCW can be applied in the advanced wastewater treatment. BPN model can effectively simulate the process of SBBR-VFCW, which also lays the foundation to the water quality forecasting system, online monitoring and automatic control technology.(4) A restoration-promoting integrated floating bed (RPIFB) was designed. Natural zeolite was used as a matrix to provide attachment condition for the emergent aquatic plant(Canna indica Linn.) and submerged plant(Potamogeton crispus Linn.) in the floating bed and sinking bed. The RPIFB was coated with an oxidation-resistant PVC net. All composition constituted a complete food chain system. The experiment water was collected from a pond reach of blue green algae and protozoans, and to creat serious eutrophication water KH2PO4,(NH2)2CO and NH4NO3was added. Trial1was conducted to compare the eutrophication purification performance among floating bed (FB), gradual-submerging bed (GSB) and RPIFB. The purification capacity of FB, GSB and RPIFB was compared through the removal efficiencies of CODcr, NO3-N, NH4+-N, TN, TP, Chl.a and water turbidity. The lighting effect to the GSB and RPIFB was also studied. In Trial2, influences of depth of GSB and photic area in RPIFB on biotas were investigated. Ecological conservation capacity of RPIFB was analyzed by observing physiological response of Canna indica Linn., Potamogeton L., Misgurnus anguillicaudatus and Bellamya aeruginosa. Results showed that the removal efficiencies of TN, TP, NH4+-N and CODCr via RPIFB were74.6%±1.4%,98.3%±4.3%,74.7%±0.5%,88.8%±1.3%and71.4%±2.5%, respectively. Chl-a and water turbidity can both reach to10%of the initial concentration. The order of purification capacities of FB, GSB and RPIFB was: RPIFB>FB>GSB. Therefore, RPIFB cannot only purify eutrophication water, but also can promote the submerged plant be restored to the water bottom. The regime shift from phytoplankton-dominated to macrophyte-dominated could be promoted. It also provides a novel idea to the ecological development of rural waters.更多还原