磷及环境因子对太湖梅梁湾藻类生长及其群落影响

在太湖梅梁湾进行的围隔试验表明,藻类生长与水华形成受气候(如水温、风浪)与营养因子(如N,P)影响。统计分析发现各点硝态氮均与叶绿素a显著负相关,在不同围隔中水温、总磷、总氮等与叶绿素a显著相关。各围隔中优势种主要为蓝藻,尤其是微囊藻类。加磷对藻类生长与群落结构均有影响,但磷营养不是目前太湖水华爆发的关键因素。     

淹没式复合型MBR处理城市生活污水的效能研究

为了缓解缺水压力，在传统膜生物反应器（CMBR）的基础上开发出了一种新型城市污水处理回用工艺——淹没式复合型膜生物反应器（SHMBR），并考察了对城市生活污水的处理效果。试验结果表明，SHMBR可以在CMBR的基础上进一步提高生物量，并明显改善了对有机物和NH4^＋-N的去除效果。试验中对TN、TP的去除效果没有提高，原因可能是生物膜的厚度不够，没有在生物膜内部形成厌氧微环境。另外，SHMBR的除磷效果没有增强还可能与生物膜的SRT较长以及聚磷菌主要生活在活性污泥中有关。     

高铁酸钾处理景观水体的效果研究

研究了高铁酸钾对景观水体中浊度、COD、溶解性COD、TN、TP和藻类的去除效果,并与聚合氯化铝(PAC)、硫酸铝和氯化铁的去除效果进行了对比,同时还考察了上述几种药剂的污泥产生情况以及高铁酸钾对水体可生化性的影响。结果表明,与其他几种混凝剂相比,高铁酸钾对浊度、COD、溶解性COD、TP和藻类的去除效果更好,但对TN的去除效果比PAC略差;高铁酸钾去除的污染物量较多,产生的污泥量较少;高铁酸钾可提高景观水体的BOD5/COD值,显著改善了水体的可生化性。     

Recycling algae to improve species control and harvest efficiency from a high rate algal pond

This paper investigates the influence of recycling gravity harvested algae on species dominance and harvest efficiency in wastewater treatment High Rate Algal Ponds (HRAP). Two identical pilot-scale HRAPs were operated over one year either with (HRAP_r) or without (HRAP_c) harvested algal biomass recycling. Algae were harvested from the HRAP effluent in algal settling cones (ASCs) and harvest efficiency was compared to settlability in Imhoff cones five times a week. A microscopic image analysis technique was developed to determine relative algal dominance based on biovolume and was conducted once a month. Recycling of harvested algal biomass back to the HRAP_r maintained the dominance of a single readily settleable algal species (Pediastrum sp.) at >90% over one year (compared to the control with only 53%). Increased dominance of Pediastrum sp. greatly improved the efficiency of algal harvest (annual average of >85% harvest for the HRAP_r compared with ∼60% for the control). Imhoff cone experiments demonstrated that algal settleability was influenced by both the dominance of Pediastrum sp. and the species composition of remaining algae. Algal biomass recycling increased the average size of Pediastrum sp. colonies by 13-30% by increasing mean cell residence time. These results indicate that recycling gravity harvested algae could be a simple and effective operational strategy to maintain the dominance of readily settleable algal species, and enhance algal harvest by gravity sedimentation.     

Removal of organics and nutrients from food wastewater using combined thermophilic two-phase anaerobic digestion and shortcut biological nitrogen removal

A process combining pilot-scale two-phase anaerobic digestion and shortcut biological nitrogen removal (SBNR) was developed to treat organics and nutrients (nitrogen and phosphorus) from food wastewater. The thermophilic two-phase anaerobic digestion process was investigated without adjusting the pH of the wastewater for the pre-acidification process. The digested food wastewater was treated using the SBNR process without supplemental carbon sources or alkalinity. Under these circumstances, the combined system was able to remove about 99% of COD, 88% of TN, and 97% of TP. However, considerable amounts of nutrients were removed due to chemical precipitation processes between the anaerobic digestion and SBNR. The average TN removal efficiency of the SBNR process was about 74% at very low C/N (TCOD/TN) ratio of 2. The SBNR process removed about 39% of TP from the digested food wastewater. Conclusively, application of the combined system improved organic removal efficiency while producing valuable energy (biogas), removed nitrogen at a low C/N ratio, and conserved additional resources (carbon and alkalinity).     

多点交替进水五箱一体化活性污泥法脱氮除磷研究

为了获得较高的氮、磷去除效率，在UNITANK工艺的基础上，开发了一种新型的城市污水脱氮除磷工艺——多点交替进水五箱一体化活性污泥法，并在南京某污水处理厂开展了中试研究。连续一年的稳定运行表明，在进水COD、BOD5、TP、NH3-N、TN分别为110～430、52～130、2．2-6．1、15～41、17-50mg／L的情况下，出水水质可稳定地达到《城镇污水处理厂污染物排放标准》（GB 18918-2002）的一级A标准．除磷率和脱氧率分别可达90％和70％以上．     

Removal of nitrogen from industrial wastewaters with the use of algal rotating disks and denitrification packed bed reactor

An attempt was made to use an algal rotating disk system in a two-step biological purification of nitrogen fertilizer industry wastewaters. The proposed method involved the removal of ammonium by Stichococcus bacillaris growing on the rotating disk and of oxidized forms of nitrogen by denitrifying bacteria. The use of a rotating algal disk followed by denitrification bed as the second step of biological treatment removed about 90% of nitrogen from the wastewater. A change of purification sequence resulted in the appearance of NO ⁻₃ and NO⁻₂ in the purified wastewater caused by the activity of nitrifying bacteria accompanying algae in the biological film on the disk. It was found that methanol used as a carbon source for denitrifying bacteria could be replaced by organic matter of algal origin.     

Bioavailability of wastewater-derived organic nitrogen to the alga Selenastrum Capricornutum

Recent attempts to control cultural eutrophication in nitrogen-limited systems have focused on the simultaneous control of all forms of nitrogen with the underlying assumption that inorganic and organic nitrogen are equally bioavailable. To assess the validity of this assumption, algal growth bioassays were conducted on denitrified wastewater effluent samples, in the presence and absence of bacteria isolated from an effluent-receiving surface water. Bioassay results indicated that wastewater-derived dissolved organic nitrogen (DON) is not bioavailable to the algae Selenastrum Capricornutum in the absence of bacteria. However, approximately half of the wastewater-derived organic nitrogen was available to the algae in the presence of bacteria during a 2-week incubation. These results suggest that while it is inappropriate to assume that wastewater-derived DON cannot cause cultural eutrophication, it will not cause as much eutrophication as inorganic nitrogen. Additional research is needed to develop methods of minimizing the discharge of bioavailable forms of wastewater-derived organic nitrogen by wastewater treatment plants.     

三种人工介质对太湖水质的改善效果

利用人工介质富集太湖水中的微生物来改善梅梁湾水源地水质,中试结果表明:三种人工介质中以组合介质(RZ)的生物量最大、生物活性最强且上部的生物量和生物活性高于中部和下部的,中间的生物量高于进水端和出水端的.在水力停留时间为6～7 d、源水CODMn为4.17～9.88 mg/L、UV254为0.09～0.13 cm-1、TN为3.35～11.6 mg/L、氨氮为0.22～5.19 mg/L、亚硝酸盐氮为0.01～0.94 mg/L、TP为0.08～0.79 mg/L的条件下,RZ对CODMn、UV254、TN、氨氮、亚硝酸盐氮、TP的平均去除率分别为22.8%、8.6%、22.1%、32.4%、49.7%、60.7%.可见通过人工介质富集微生物的方法对太湖梅梁湾水源地水质有明显的改善.     

Simultaneous removal of carbon and nutrients from an industrial estate wastewater in a single up-flow aerobic/anoxic sludge bed (UAASB) bioreactor

Simultaneous removal of carbon and nutrients (CNP) in a single bioreactor is highly significant for energy consumption and control of reactor volume. Basically, nutrients removal is dependant to the ratio of biochemical oxygen demand to chemical oxygen demand (BOD₅/COD). Thus, in this study the treatment of an industrial estate wastewater with low BOD₅/COD ratio in an up-flow aerobic/anoxic sludge bed (UAASB) bioreactor, with an intermittent regime in aeration and discharge, was investigated. Hydraulic retention time (HRT) of 12-36 h and aeration time of 40-60 min/h were selected as the operating variables to analyze, optimize and model the process. In order to analyze the process, 13 dependent parameters as the process responses were studied. From the results, it was found, increasing HRT decreases the CNP removal efficiencies. However, by increasing the BOD₅ fraction of the feed, the total COD (TCOD), slowly biodegradable COD (sbCOD), readily biodegradable COD (rbCOD), total nitrogen (TN), and total phosphorus (TP) removal efficiencies were remarkably increased. Population of heterotrophic, nitrifying and denitrifying bacteria showed good agreement with the results obtained for TCOD and TN removal. The optimum conditions were determined as 12-15 h and 40-60 min/h for HRT and aeration time respectively.     

Algal growth in primary settled sewage: The effects of five key variables

Photoperiod, at 3240 lx (300 ft candle) light intensity, was found to be the primary limiting factor for algal biomass growth in a bench scale series of experiments using primary settled sewage. At a retention time of seven days, a total effective photoperiod of greater than 6 h a day was required to produce algae at concentration above 500 mg 1⁻¹.Increasing dissolved CO₂ concentration promoted green algae production and resulted in a higher yield than that obtained from the blue green algae which dominated at low levels of dissolved CO₂. Unfortunately, most of the green algae were unicellular, discrete, small particles, and would be expensive to harvest compared with blue-green algae which often grow in colonies possessing a gelatinous sheath or are of filamentous construction.Low temperature favoured algal biomass production because of its effect upon the solubility of CO₂. The addition of bicarbonate also increased algal biomass yield but an excess of ammonium nitrate inhibited algal production.The removal of nitrogen and phosphorus by algae varied with the quantity of algal biomass produced. Under the experimental conditions, nitrogen removal corresponded to about 3 mg per 100 mg of biomass produced and phosphorus removal to about 0.5 mg per 100 mg biomass produced.     

Influence of operational parameters on nitrogen removal efficiency and microbial communities in a full-scale activated sludge process

To improve the efficiency of total nitrogen (TN) removal, solid retention time (SRT) and internal recycling ratio controls were selected as operating parameters in a full-scale activated sludge process treating high strength industrial wastewater. Increased biomass concentration via SRT control enhanced TN removal. Also, decreasing the internal recycling ratio restored the nitrification process, which had been inhibited by phenol shock loading. Therefore, physiological alteration of the bacterial populations by application of specific operational strategies may stabilize the activated sludge process. Additionally, two dominant ammonia oxidizing bacteria (AOB) populations, Nitrosomonas europaea and Nitrosomonas nitrosa, were observed in all samples with no change in the community composition of AOB. In a nitrification tank, it was observed that the Nitrobacter populations consistently exceeded those of the Nitrospira within the nitrite oxidizing bacteria (NOB) community. Through using quantitative real-time PCR (qPCR), nirS, the nitrite reducing functional gene, was observed to predominate in the activated sludge of an anoxic tank, whereas there was the least amount of the narG gene, the nitrate reducing functional gene.     

水解酸化/MBR工艺处理混合污水的中试研究

将膜生物反应器与脱氮除磷工艺相结合,建立水解酸化/好氧MBR中试装置,针对以精细化工废水和造纸废水为主的市政混合污水进行处理,系统考察了工艺的运行情况和处理效果.结果表明,在进水COD为335～941 mg/L、NH3-N为11.1～28.7 mg/L、TN为31.2～38.6mg/L、TP为1.0～17.4 mg/L的条件下,当系统水力停留时间约为48 h时,对COD、NH3-N、TN和TP的平均去除率分别为87.1%、91.0%、61.2%和93.7%.其中,出水NH3-N、TN和TP浓度均可达到GB 18918-2002的一级B标准;由于污水中难降解有机物的含量较高,导致出水COD浓度不能稳定达标,对此可在系统后设物化处理单元加以解决.     

塔式复合人工湿地处理农村生活污水的试验研究

考察了新型人工湿地——塔式复合人工湿地（TICW）对农村生活污水的处理效果。结果表明,TICW对污染物具有较高的去除能力,脱氮效果尤其明显,对COD、NH4^＋-N、TN、TP的去除率分别为72％、82％、83％、63％;TICW的瀑布式水流增强了污水的充氧效果,湿地土壤中氨化菌、硝化菌的数量均较多,分别为10^7～10^8 CFU／g土壤和10^4～10^5 MPN／g土壤,提高了湿地的脱氮性能;木本植物和地方特有的经济作物——蔺草的结合使用使湿地在冬季仍能保持较高的除污能力。     

改性硅藻土在处理城市污水中的应用探讨

研究了改性硅藻土应用于城市污水的技术原理,分析了改性硅藻土投加量对污水中COD,TP,TN及氨氮的去除率的影响,并指出改性硅藻土处理城市污水有很大的经济效益,是我国应大力发展的一门技术.     

MBBR用于南方某污水厂强化脱氮效果分析

浙江某污水厂设计规模为16×10⁴m³/d,采用Bardenpho—MBBR工艺进行升级改造后,生化池出水COD、NH₄⁺-N、TN、TP均值分别为17. 2、0. 37、7. 72、0. 168 mg/L,在不投加碳源的情况下即可达到准Ⅳ类水标准,生物脱氮除磷效果良好。对生化池各功能区沿程采样测定发现,好氧MBBR区对TN的去除率为28%～46%,受到泥浆水冲击后也能保持在15%～22%,系统高效去除TN得益于好氧MBBR区的同步硝化反硝化(SND)作用;由于好氧区的SND现象,平均可以节省0. 23元/m3的碳源费用,年节约碳源费用近1 343. 2万元;生物膜厚度和溶解氧的控制对于稳定表现SND有重要影响;系统中微生物的高通量测序结果显示,悬浮载体上硝化菌丰度为32. 19%、反硝化菌丰度为4. 86%,硝化菌和反硝化菌同时存在为SND现象的产生提供了微观保证;冬季低温时,悬浮载体实际承担了系统近90%的硝化负荷。     

Heterotrophic activity compromises autotrophic nitrogen removal in membrane-aerated biofilms: results of a modeling study

A 1-d multi-population biofilm model was constructed to study the effect of heterotrophic activity on completely autotrophic ammonium (NH4+) removal in membrane-aerated (counter-diffusion) versus conventional biofilm systems (co-diffusion). Growth of heterotrophic bacteria (HB) was supported either solely by biomass decay products or by organic carbon (as chemical oxygen demand (COD)) in the influent. Three scenarios were considered: influence of HB growing on biomass decay products on steady-state performance (total nitrogen (TN) removal efficiency); influence of the influent COD/N ratio on steady-state performance (supplying COD in the influent); and impact of dynamic changes in the influent COD/N ratio on TN removal efficiency. The results revealed that the TN removal efficiency in the counter-diffusion biofilm was significantly different when HB were included in the simulations at NH4+ surface loads of LNH4>2.7 g - N m(-2) d(-1). Influent COD significantly altered the microbial community composition in the counter-diffusion biofilm and anaerobic NH4+ oxidation could not be sustained at COD/N>2. The co-diffusion system, however, was less affected and more than 50% of the TN removal originated from anaerobic NH4+ oxidation at those ratios. Perturbation experiments showed that step increases to influent COD/N ratios of 2 or higher over a period of 50 d or longer caused a loss of anaerobic NH4+ oxidation capacity which could not be regained within a reasonable time frame (>1000 d) in the counter-diffusion system. In contrast, simulating a 1-d sloughing event only caused a disturbance of 200 d although a maximum biofilm loss of 90-95% occurred. These results clearly indicate the importance of heterotrophic activity in autotrophic N removal biofilms, especially in counter-diffusion systems where they may compromise N removal capacity.     

Wastewater treatment by reed beds: An experimental approach

The present study consists of assessing the efficiency of a macrophyte (Phragmites australis) system in wastewater purification in an arid climate. The experimental system is made up of three beds differing in length (30, 40 and 50 m) and implanted with Phragmites australis. Wastewater inflow through these beds is horizontal with a flow of 10 l.s⁻¹. Retention time varies between 1 and 4 h. The frequency of irrigation is weekly. The studied parameters are: the organic load (COD and TSS), nutrients (total Kjeldhal nitrogen: TKN and total phosphorus: TP) and the parasitical load (helminth eggs). Water, soil and plants are the three components of the experimental system we analyzed.Results reveal that in the output, the decrease in organic load, nutrients and parasitical load is very sharp in the large bed (COD: 62%, TKN: 43%, TP: 14%, helminth eggs: 93%). However, in the small bed (30 m), the decrease is slight (COD: 48%, TKN: 23%, TP: 5%, helminth eggs: 88%). Concerning parasitical load, the study shows that the three beds are effective in eliminating helminth eggs, even with a very short retention time (1–4 h). The quality of the effluent of the reed bed system should be classified within category B according to WHO guidelines (1989) for crops irrigation.Soil sample analysis from entrance to exit shows a decreasing gradient of nitrogen (N), phosphorus (P), organic carbon (Org.C), organic matter (OM) and parasitical helmith eggs. The gradient becomes more significant in the largest bed with decreasing rate, reaching respectively 49%, 44%, 37%, 40% and 100% for TKN, TP, Org.C, OM and helminth eggs.As for the plant material, the composition of major elements (nitrogen and phosphorus) of Phragmites aerial parts shows the same evolution. While the decreasing rate of nitrogen in the leaves reaches 50% in the largest bed, it does not exceed 8% in the smallest bed. Mean aerial productivity of the studied reed beds was estimated at 134 tons dry weight.ha⁻¹. The aerial biomass exported contains only 5–6% of nitrogen and 10–12% of phosphorus with regard to their load at the influent.     

悬浮填料SBBR处理生活污水的运行工况优化研究

采用自行设计的悬浮填料序批式生物膜反应器(SBBR)对生活污水进行了脱氮除磷试验研究。结果表明,在常温下该反应器的最优运行工况为:瞬时进水、厌氧3h、曝气5h、沉淀20min、出水10min。当反应器在此工况下运行时,对COD、NH3-N、TN、TP的平均去除率分别为95.00%、95.76%、72.16%、97.45%,出水COD、NH3-N、TN、TP均达到了《城镇污水处理厂污染物排放标准》(GB18918—2002)的一级A标准。     

气水比对高分子填料BAF脱氮效能的影响

采用高分子载体作为生物填料,以模拟生活污水为处理对象,对两级曝气生物滤池(BAF)的脱氮效能进行了试验研究,着重考察了气水比对BAF去除COD、NH3-N和TN的影响,并探讨了系统内氮素的转化规律和提高脱氮效能的途径。结果表明,当平均水温为22~32℃、进水流量为4 L/h、进水COD为150 mg/L左右、进水NH3-N为60 mg/L左右、一级BAF的气水比为4∶1、二级BAF的气水比为2∶1时,系统的处理效果最佳,对COD、NH3-N和TN的总平均去除率分别达到84.33%、87.84%和56.06%。系统通过同时短程硝化反硝化实现了低能耗、高效率的脱氮。