新型SBR工艺处理生活废水的研究

新型SBR工艺是在传统SBR反应器中加一隔板,将反应器从空间上分成上下两个区域,上面是好氧区,下面为缺氧厌氧区。实验通过水力停留时间和上下区域体积比对脱氮除磷效果影响的研究,确定该工艺的最佳运行工况和反应器内挡板位置;同时与传统SBR工艺进行对比实验研究。结果表明,进水60 m in,曝气240 m in,沉淀30 m in,排水15 m in,闲置15 m in;上下区域体积比为1∶1时脱氮除磷效果最佳,TN和TP去除率达到88.7%和78.4%,其效果均好于传统SBR工艺。     

污水生物脱氮除磷新工艺的研究

传统的生物脱氮除磷技术效率低下,导致氮、磷去除率不迭标,是造成水体的富营养化的主要原因.概述了传统生物脱氮除磷原理,分析了传统生物脱氮除磷工艺的不足,并介绍了反硝化除磷、同时硝化反硝化、短程硝化反硝化、厌氧氨氧化等几种生物脱氮除磷新技术的原理与典型工艺.最后对生物脱氮除磷技术的发展趋势进行了展望,指出经济、高效、低能耗...     

电解脱氮除磷技术在海产养殖废水治理中的研究

海产养殖迅速发展造成水域富营养化、赤潮频发,海产养殖废水污染的治理迫在眉睫。为解决此问题将电解脱氮除磷技术应用在海产养殖废水处理中,并探讨电压、pH、极板间距和电解时间对脱氮除磷去除率的影响。结果表明:脱氮除磷的去除率与电压成正相关,与极板间距成负相关。在电压为30V,极板间距10cm,pH为7时,NH_4~+-N、NO_3~--N和TP的去除率达到最大分别为72%、90%、85%。     

ABR-生物接触氧化工艺处理低碳氮比生活污水试验

近年来,城市生活污水呈现出低碳氮比的趋势,造成污水处理脱氮困难.采用ABR-生物接触氧化工艺对低碳氮比生活污水进行试验研究,确定了试验运行参数,即在进水COD/N为2～7范围内,当HRT=10 h,R=2.5、T=30℃时,系统对TN的去除效果良好;TN的平均去除率随着碳氮比的减小而迅速降低,此时,碳源不足成为制约脱氮效果的主要原因;在最佳运行条件下,当进水COD/N为6～7时,TN平均去除率达到80%以上,出水TN质量浓度小于15 mg/L,满足<城镇污水处理厂污染物排放标准>一级A标准.     

分级式除磷脱氮工艺探讨

综合考虑生物除磷与脱氮对环境条件的要求,提出了分级式除磷脱氮的工艺模式,旨在将聚磷菌与硝化菌分别控制在两级反应器中优势生长,以解决硝化菌与其他细菌混合生长系统在除磷与脱氮过程中存在的矛盾关系,达到优化除磷脱氮目的.探讨了分级式除磷脱氮的工艺流程、优化除磷脱氮的可行性及研究要点.     

浅析人工湿地对污水处理厂处理后中水的净化作用及问题探讨

人工湿地是人为因素形成的湿地，由水体、基质、水生植被和微生物四个基本组成要素构成的，是一种生态治理污水的方法。皂河人工湿地是西安市为改善皂河入渭口水质而建设的人工湿地。经分析，皂河人工湿地对皂河污水中的主要指标均有明显去除效果，但是，对污水处理厂处理后的中水除氮、磷外，其他指标处理效果不明显。针对人工湿地净水植物随着年份增加，根系逐步板结、生长愈发缓慢、净水能力下降的问题，可以采取调整湿地整体功能、更新净水植物及创新管理运行方式等措施，更好发挥人工湿地的净化作用。     

低密度沸石复合填料的制备及其性能研究

以天然沸石为主要原料,水泥为粘结剂,发泡聚苯乙烯球形颗粒为内核,经复合、成球、筛分、养护,制备出粒径4~8 mm的免烧球形低密度沸石复合填料。对制备的材料进行了空隙率、表观密度、强度等性能测试。研究结果表明,制备低密度沸石复合填料的最优工艺组合条件为质量百分比沸石∶水泥=75%∶25%,自然条件下养护7~10d,此时制备的成品填料空隙率为47.4%,表观密度为1.23 g/cm3,强度为61.5 N,堆积密度为0.647 g/cm3。扫描电镜图像表明,挂膜前填料表面粗糙,内部存在大量孔隙,挂膜后表面和内部均有大量的微生物附着,与粉煤灰制备的陶粒相比,该填料挂膜微生物量提高了一倍。本研究制备的低密度沸石复合填料,用于在环境温度低于15℃下曝气生物滤池的挂膜启动运行,对氨氮的去除率达到96%,具有较好的氨氮去除效果,表明该复合填料在废水脱氮深度处理方面具有良好的应用前景。     

表面流人工湿地处理糠醛生产废水的应用

根据糠醛生产废水的特点,利用生产企业所处低洼盐碱地改造成表面流人工湿地,废水在湿地内以自然消耗的方式处理,无外排,处理的废水量等于湿地内废水的自然蒸发量、植物的蒸腾量与植物的贮存量。研究表明,经湿地处理后的废水COD去除率平均为94%,TN去除率平均为65%,TOC去除率平均为94.9%。处理后的废水pH值为6.22。     

多层渗滤介质处理微污染水体的中试研究

对传统的渗滤系统进行改进,采用多层渗滤介质系统,以期增大人工土层对颗粒有机物的接触氧化表面积,同时设置曝气装置保证好氧过程的氧气供应,可以大大提高污水地下处理系统的水力负荷。以北京典型的细砂、中砂、粗砂和砾石为填充材料,处理北京市海淀区上庄水库的污染水体,远优于类似的系统。现场试验结果表明,改进后的系统能创造良好的好氧/厌氧环境,对污染物去除效果良好,COD_Cr、TN、NH⁺₄-N和TP去除率分别达到了48.57%~94.87%、18.49%~70.21%、20.51%~87.50%和5692%~80.65%,出水达到了地表水Ⅲ-Ⅳ类水质标准。多层渗滤介质系统通过微生物的硝化、反硝化作用实现生物脱氮是去除氮的主要途径;土壤的吸附与沉淀作用是去除磷的主要途径。      

天然沸石曝气生物滤柱脱氮性能及生物再生

对二级天然沸石曝气生物滤柱的脱氮性能和生物再生进行了实验研究.研究结果表明,在进水有机负荷0.8～6.4 kgCOD/(m3·d)、水力负荷1～2 m/h、气水比1:1～4:1的工艺条件下,COD、氨氮和总氮去除率分别达到67%～90%、52%～82%和33%～67%;水中氨氮含量在10～30mg/L时,硝化速率为0.23mg/min.生物再生过程中,微生物不仅硝化解吸氨氮,还可以深入沸石孔道,直接利用沸石吸附的氨氮.分级分段进水可以提高沸石生物再生速度,减少再生时间.     

Effects of plants development and pollutant loading on performance of vertical subsurface flow constructed wetlands

The influent concentration has a great effect on nutrients removal efficiency in vertical subsurface flow constructed wetland systems, but treatment performance response to different C: N: P ratios in the influent are unclear at present. At the first growing seasons, the effects of the plants present or not, season, the different C: N: P ratio in influent condition and their interaction on treatment performances were studied in the planted or the unplanted wetlands in greenhouse condition. Each set of units was operated at hydraulic loading rates of 40 L/d. Low, medium and high-strength (100, 200, 400 mg/L of chemical oxygen demand or 20, 40, 80 mg/L total nitrogen) synthetic sewage were applied as influent. According to the first growing season results, the average removal efficiencies for the unplanted and the planted wetlands were as follows: chemical oxygen demand (44–58 % and 55–61 % respectively), total nitrogen (26–49% and 31–54 %) and total phosphorus (36–64 % and 70–83 %). The both wetlands system was operated as an efficient treatment system of highest average removal rates of both chemical oxygen demand and total phosphorus when medium-strength synthetic sewage were applied. When high strength synthetic sewage was applied, the planted wetlands usually had a higher nutrients removal rates than the unplanted over the study period. The plants grew well under any high loading treatment over the study period. Anyhow, it also proved that the wetland systems have a good capacity to treat different strength wastewater in greenhouse condition.     

Floating wetland mesocosm assessment of nutrient removal to reduce ecotoxicity in stormwater ponds

A grouped mesocosm study was conducted with different water holding capacities and conditions to determine nutrient removal efficiency using floating wetland macrophytes. Different scenarios were created by changing water depth, littoral vegetation, sorption media and area coverage to observe how they affect nutrient removal efficiencies. Plant species were screened and selected based on the literature, local availability and previously performed microcosm studies. Sorption media were warped using geotextile filter fostering microbial colonization in the rhizospheric zone to enhance denitrification and plant growth. Water quality parameters included total nitrogen, total phosphorus, orthophosphate, nitrate?Cnitrogen and ammonia?Cnitrogen in addition to in situ parameters such as pH, dissolved oxygen, temperature and chlorophyll-a. Composite samples across several locations were collected periodically to understand the spatial distribution or aggregation of nutrients. After 3?months of water quality monitoring, plants were analyzed for tissue nutrient concentrations, and the average uptake rate was calculated as 36.39 and 1.48?mg?m^?2?day^?1 for nitrogen and phosphorus, respectively, by the floating treatment wetland system. Finally, considering the higher nutrient aggregation in the rhizospheric zone, the removal rate with 5?% area coverage and water quality improvement by littoral zone, the optimized design, placement and maintenance of the whole system were recommended.     

The influence of three mangrove species on the distribution of inorganic nitrogen and phosphorus in the Quanzhou Bay estuarine wetland soils

This study aims to investigate the effects of region and three regional dominated mangrove species (Avicennia marina, Aegiceras corniculatum and Kandelia candel) on the distribution of inorganic nitrogen and phosphorus. Measurement of the inorganic nitrogen and phosphorus and enzymatic activities was carried out in soils covered by three mangrove species in the Quanzhou Bay estuarine wetlands, a typical coastal wetland in China. Species with a higher biomass in upstream and midstream absorb more nitrogen from soils, and the retention of the available phosphorus in the soils of different regions causes the regional variation of phosphorus. In areas dominated by A. marina, nitrate nitrogen is lower while available phosphorus is higher. Meanwhile, nitrate nitrogen and available phosphorus are higher in the soils covered by K. candel. Moreover, all three species affect the elemental and enzymic stoichiometry. The mangrove species influences the diversity of the elemental and enzymic stoichiometric relationship through differential microenvironments, which induce the biodiversity of wetland ecosystems. Thus, this study may facilitate a better understanding of the transformation ability of mangroves to nitrogen and phosphorus and will therefore be beneficial for providing a basis for the ecological restoration of estuarine wetlands.     

再力花/菖蒲生物湿地床去除河水中氮磷的试验

采用再力花和菖蒲构建湿地床,以考察其对污染河水的净化效果。6个月的连续试验表明:在水力负荷为0.24 m3/(m2.d)、植物种植密度大于158株/m2的条件下,2种植物存活率均大于93%,说明植物能适应低污染负荷、高种植密度的无土培养环境;再力花和菖蒲湿地床月均去除率分别为:总氮(TN),48.22%～78.53%和43.23%～72.42%;总磷(TP),77.62%～85.67%和58.07%～80.77%。再力花湿地床对TN、TP的净化效果好于菖蒲湿地床;2种植物吸收N、P含量分别占去除总量的比例:N为44.14%、37.75%,P为73.43%、62.05%。湿地床技术可有效去除来水中的TN、TP,通过植物吸收作用累积N、P含量较高,不同种类的植物构建湿地床对污染河水中N、P去除效果存在显著差异,且硝化反硝化和植物吸收是去除N的主要途径,而植物吸收是去除P的有效手段。     

Investigations of subsurface flow constructed wetlands and associated geomaterial resources in the Akumal and Reforma regions,Quintana Roo,Mexico

Subsurface flow constructed wetlands in the village of Akumal, Quintana Roo, Mexico were surveyed to determine the general status of the wetland systems and provide baseline information for long term monitoring and further study. Twenty subsurface flow wetlands were surveyed and common problems observed in the systems were overloading, poor plant cover, odor, and no secondary containment. Bulk mineral composition of aggregate from two subsurface flow constructed wetlands was determined to consist solely of calcite using bulk powder X-ray diffraction. Some soil structure is developed in the aggregate and aggregate levels in wetlands drop at an estimated rate between 3 and 10 cm/year for overloaded wetlands owing to dissolution. Mineral composition from fresh aggregate samples commonly is a mixture of calcite and aragonite. Trace amounts of Pb, Zn, Co, and Cr were observed in fresh aggregate. Coefficients of permeability (k) varied from 0.006 to 0.027 cm/s with an average values being 0.016 cm/s. Grain size analysis of fresh aggregate samples indicates there are unimodal and multimodal size distributions in the samples with modes in the coarse and fine sand being common. Investigations of other geologic media from the Reforma region indicate that a dolomite with minor amounts of Fe-oxide and palygorskite is abundant and may be a better aggregate source that the current materials used. A Ca-montmorillonite bed was identified in the Reforma region as well and this unit is suitable to serve as a clay liner to prevent leaks for new and existing wetland systems. These newly discovered geologic resources should aid in the improvement of subsurface flow constructed wetlands in the region. Although problems do exist in these wetlands with respect to design, these systems represent a successful implementation of constructed wetlands at a community level in developing regions.     

潜流构建湿地氮素转化运移的理论模型研究

构建湿地中氮素的主要存在形态为有机氮和无机氮,无机态氮主要包括氨态氮和硝态氮两种形态。一方面,这些氮素之间通过矿化、氨同化、硝化、反硝化、吸附交换、植物吸收等物理、化学及生物学过程相互联系并相互转化;另一方面在构建湿地污水处理系统中,从进水到出水,这些不同形态的氮素又随多孔介质中的饱和流发生运移。根据氮素的转化机理和溶质运移理论,以构建湿地中氮素的溶质运移模型为基础,将氮素转化的机理过程作为源汇项包括到基本模型中,由不同形态氮素的运移转化模型相联合形成构建湿地中氮素转化运移的理论模型系统。根据文献调研,给出模型系统参数的参考值,并简要介绍了模型系统的计算机语言求解方法。该模型为深入研究构建湿地中污水脱氮综合机理提供工具,其结果为以脱氮为目的的构建湿地的设计提供科学参考。     

Simultaneous nitrification–denitrification of wastewater: effect of zeolite as a support in sequential batch reactor with step-feed strategy

One of the technologies used for wastewater nitrogen removal consists in simultaneous nitrification–denitrification. The low microbial growth rate and the low availability of organic material for the denitrification stage make it necessary to study new operational conditions and the use of microbial supports. The aim of this study was to evaluate the operational behavior of a simultaneous nitrification–denitrification process in a sequential batch reactor utilizing zeolite as a biomass support and step-feed strategy. Two reactors of 2 L were used, one with zeolite and another without zeolite, both operated at constant temperature (31 °C), varying nitrogen loading rate (NLR) from 0.041 to 0.113 kg total Kjeldahl nitrogen (TKN/m³/day). After 209 days, removals higher than 86 and 96 % in nitrogen compounds and organic matter were obtained, respectively. There was not accumulation of nitrate and nitrite in any case; this means that there was a simultaneous nitrification–denitrification in the reactors. The incorporation of zeolite in the system held higher concentration of biomass in the reactor; this led to reduce start-up to 21 days and to improve 11.31 % removal kinetic. The use of a step-feed strategy prevents events of inhibition by substrate, even duplicating tolerance to higher NLR for the same operation time.     

皖江经济带湿地遥感现状调查及变化规律研究

利用MSS、ETM+、CBERS-2、BJ-2、02C和TH1多时相卫星遥感数据,分别提取1975年、2000年、2007年和2016年皖江经济带湿地现状及变化的遥感信息,研究皖江经济带湿地遥感现状及变化规律.结果 表明:皖江经济带湿地类型主要为河流湿地、湖泊湿地、沼泽湿地和人工湿地,市县级地域湿地分布不均、类型不全;19752016年,人工湿地面积增加,增长率为55.32%;沼泽湿地面积减少,减少率为69.97%;湖泊湿地和河流湿地面积较稳定,增长率分别为1.80%和2.06%.湿地变化分两个阶段:第一阶段(1975-2007年),湿地面积总体增加,河流湿地、湖泊湿地和沼泽湿地面积减少,人工湿地面积增加;第二阶段(2007-2016年),湿地面积总体增加,但河流湿地和湖泊湿地面积增加,沼泽湿地面积继续减少,人工湿地面积继续增加,湿地面积增减受人类活动影响较大.     

Potency of constructed wetlands for deportation of pathogens index from rural,urban and industrial wastewater

Pathogen removal is essential for wastewater treatment and its potential reuse in agriculture. Three field-scale wastewater treatment systems consisting of free surface flow were operated around 1.5 years receiving water from urban domestic, rural domestic and industrial sources. The study was conducted to evaluate seasonal performance of constructed wetland systems in removing Escherichia coli, Enterococci and total coliforms under continuous hydraulic flow. Results displayed that all three wetlands gain recognition in removing pathogen load with high removal efficacy till water reaches output ports. Removal efficiencies were even higher, 66–93, 78–92 and 80–94% for E. coli, Enterococci and total coliforms, respectively, within constructed wetlands. Remarkably at shorter temporal scales in CW-A, greater homogeneity of pathogen concentrations was assessed at wetland outlet sites. In outlet ports, results displayed a highly effective removal of E. coli concentration 80–90% (June 2015), 86–92% (October 2015) and 79–92% (February 2016), Enterococci 80–94% (June 2015), 83–94% (October 2015) and 80–94% (February 2016) and total coliforms 85–93% (June 2015), 87–95% (October 2015) and 88–96% (February 2016). Positive correlation was observed between bacterial indicators (E. coli–Enterococci, r = 0.038; p < 0.01 and E. coli–total coliforms, r = 0.142; p < 0.01). Removal of bacterial indicators in constructed wetland was also displayed by PCA in which three-component analysis of variance was 98.39% and showed a clear decrease in measured parameter gradients toward samples from outlet ports. Constructed wetlands provide cost-effective treatment systems for reducing the pathogen load in wastewater in variable agro-climatic conditions and thus improve water quality.     

Effect of vegetation on the performance of horizontal subsurface flow constructed wetlands with lightweight expanded clay aggregates

This research evaluates the effect of both organic and ammonia loading rates and the presence of plants on the removal of chemical oxygen demand and ammonia nitrogen in horizontal subsurface flow constructed wetlands, 2 years after the start-up. Two sets of experiments were carried out in two mesocosms at different organic and ammonia loading rates (the loads were doubled); one without plants (control bed), the other colonized with Phragmites australis. Regardless of the organic loading rate, the organic mass removal rate was improved in the presence of plants (93.4 % higher for the lower loading rate, and 56 % higher for the higher loading rate). Similar results were observed for the ammonia mass removal rate (117 % higher for the lower loading rate, and 61.3 % higher for the higher loading rate). A significant linear relationship was observed between the organic loading rate and the respective removal rates in both beds for loads between 10 and 13 g m^?2 day^?1. The presence of plants markedly increase removal of organic matter and ammonia, as a result of the role of roots and rhizomes in providing oxygen for aerobic removal pathways, a higher surface area for the adhesion and development of biofilm and nitrogen uptake by roots.