Operation of a full-scale pumped flow biofilm reactor (PFBR) under two aeration regimes

A novel technology suitable for centralised and decentralised wastewater treatment has been developed, extensively tested at laboratory-scale, and trialled at a number of sites for populations ranging from 15 to 400 population equivalents (PE). The two-reactor-tank pumped flow biofilm reactor (PFBR) is characterised by: (i) its simple construction; (ii) its ease of operation and maintenance; (iii) low operating costs; (iv) low sludge production; and (v) comprising no moving parts or compressors, other than hydraulic pumps. By operating the system in a sequencing batch biofilm reactor (SBBR) mode, the following treatment can be achieved: 5-day biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total suspended solids (TSS) reduction; nitrification and denitrification. During a 100-day full-scale plant study treating municipal wastewater and operating at 165 PE and 200 PE (Experiments 1 and 2, respectively), maximum average removals of 94% BOD5, 86% TSS and 80% ammonium-nitrogen (NH4-N) were achieved. During the latter part of Experiment 2, effluent concentrations averaged: 14 mg BOD5/l; 32 mg COD(filtered)/l; 14 mg TSS/l; 4.4 mg NH4-N/l; and 4.0 mg NO3-N/l (nitrate-nitrogen). The average energy consumption was 0.46-0.63 kWh/m3(treated) or 1.25-1.76 kWh/kg BOD5 removed. No maintenance was required during these experiments. The PFBR technology offers a low energy, minimal maintenance technology for the treatment of municipal wastewater.     

Performance of a combined eco-system of ponds and constructed wetlands for wastewater reclamation and reuse.

An on-site study on the operational performance of a combined eco-system of ponds and SF constructed wetland for municipal wastewater treatment and reclamation/reuse in Donging City, Shandong, China was carried out from January 2001 through October 2003. The removal efficiencies for various main parameters were: TSS 84.8 +/- 7.3%, BOD5 87.2 +/- 5.3%, CODCr 70.2 +/- 18.6%, TP 52.3 +/- 23.1%, and NH(3)-N 54.8 +/- 23.9% with effluent concentration of TSS 9.12 +/- 5.12 mg/l, BOD5 6.44 +/- 4.58 mg/l, CODCr, 42.8 +/- 6.7 mg/l, TP 0.94 +/- 0.27 mg/l and NH(3)-N 7.95 +/- 2.36 mg/l. In addition, the removal efficiencies for faecal coliforms and total bacteria were > 99.97% and > 99.998% respectively, which well meet Chinese National standards for effluent quality of municipal wastewater treatment plants. The composition of TSS was closely related to CODCr and BOD5 variations, and nitrification-denitrification is the major mechanism of nitrogen removal both in ponds and in wetlands. In addition, sedimentation also played an important role in the removal of TSS, nitrogen, phosphorus and BOD5. The removal efficiencies of various parameters, the number of species and biomass of biological community in the system increased gradually with the ecological maturation.     

Treatment of slaughterhouse plant wastewater by using a membrane bioreactor

The use of a membrane bioreactor (MBR) for removal of organic substances and nutrients from slaughterhouse plant wastewater was investigated. The chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) concentrations of slaughterhouse wastewater were found to be approximately 571 mg O2/L, 102.5 mg/L, and 16.25 mg PO4-P/L, respectively. A submerged type membrane was used in the bioreactor. The removal efficiencies for COD, total organic carbon (TOC), TP and TN were found to be 97, 96, 65, 44% respectively. The COD value of wastewater was decreased to 16 mg/L (COD discharge standard for slaughterhouse plant wastewaters is 160 mg/L). TOC was decreased to 9 mg/L (TOC discharge standard for slaughterhouse plant wastewaters is 20 mg/L). Ammonium, and nitrate nitrogen concentrations of treated effluent were 0.100 mg NH4-N/L, and 80.521 mg NO3-N/L, respectively. Slaughterhouse wastewater was successfully treated with the MBR process.     

Design and operation of an eco-system for municipal wastewater treatment and utilization.

An eco-system consisting of integrated ponds and constructed wetland systems is employed in Dongying City, Shandong Province for the treatment and utilization of municipal wastewater with design capacity of 100,000 m(3)/d. The total capital cost of this system is 680 Yuan (RMB) or US dollars 82/m(3)/d, or about half that of the conventional system based on activated sludge process, and the O/M cost is 0.1 Yuan (RMB) or US dollars 0.012/m(3), only one fifth that of conventional treatment systems. The performance of the wastewater treatment and utilization eco-system is quite good with a final effluent COD, BOD, SS, NH3-N and TP of 45-65 mg/l, 7-32 mg/l, 12-35 mg/l, 2-13 mg/l and 0.2-1.8mg/l respectively and the annual average removals of COD, BOD, SS, NH3-N and TP are 69.1%, 78.3%, 76.4%, 62.1% and 52.9%o respectively, which is much better than that of conventional pond system or constructed wetland used separately and illustrates that the artificial and integrated eco-system is more effective and efficient than the simple natural eco-system.     

天津市于桥水库水质变化特点及影响因素分析

采用非参数Mann-Kendall检验和Sen方法对于桥水库1986-2005年的水质参数(pH值、DO,COD,BOD5和NH3-N)的变化趋势和趋势量进行了统计和分析.结果表明:近20年来于桥水库水质能够满足其水功能规划Ⅲ类水质标准要求,pH值、D0,BOD5和NH3-N质量浓度均达到Ⅱ类水质标准,COD质量浓度也...     

Biodegradability enhancement of municipal landfill leachate

The method of enhancing the biodegradability of landfill leachate via air stripping followed by coagulation/ultrafiltration （UF） processes is introduced. In this study, the air stripping process obtained a removal efficiency of 88.6% for ammonia nitrogen （NH3-N）, at an air-to-liquid ratio （A/L） of 3 300 （pH = 11） and after 18 h of stripping. The single coagulation process increased the BOD （biological oxygen demand）/COD （chemical oxygen demand） ratio by 0.089 with a FeCl3 dosage of 570 mg/L, at pH 7.0, and the single UF process increased the BOD/COD ratio from 0.049 to 0.311. However, the combination of coagulation and UF increased the BOD/COD ratio from 0.049 to 0.423, and the final BOD, COD, NH3-N, and colour of the leachate were 1 023 mg/L, 2 845 mg/L, 145 mg/L, and 2 056, respectively, when a 3 kDa molecular weight cut-off （MWCO） membrane was used at an operating pressure of 0.7 MPa. In the ultrafiltration process, the average solution flux （Jv）, concentration multiple （Mc）, and retention rate （R） for the COD were 107.3 L/（m^2·h）, 6.3, and 84.2%, respectively.     

土壤过滤系统处理农村生活污水的 试验研究

采用一种土壤过滤系统处理农村生活污水,考察了该工艺对CODCr、BOD5、NH3-N、全氮（TN）和全磷（TP）的去除效果。实验结果表明,当水力负荷约为0.05 m3/（m2·d）, 水力停留时间为3 d时。该土壤过滤系统对CODCr、BOD5、NH3-N、全氮（TN）和全磷（TP）的去除效果较好,平均去除率分别达到84.6%、83.3%、64.3%、59.8%和70%。出水CODCr约为18.3~42.1 mg/L,BOD5约为8.9~17.3 mg/L,NH3-N约为11.2~17.7 mg/L,TN约为21.2~31.3 mg/L,TP小于2.0 mg/L,出水水质优于农田灌溉水质标准（GB 5084—2005）。气温变化和进水污染物浓度对处理效果影响明显。总体上来讲,温度大于22 ℃时,进水污染物浓度越低处理效果越好。     

Membrane bioreactor application in wastewater re-use from the effluent of Bali primary WWTP, northern Taiwan.

Two MBR pilot systems were constructed and tested in the Bali Primary WWTP. The pilot study shows that two MBR systems, i.e. the Green-MenBio system (MBR-1) and the Bio-MF system (MBR-2), can both fulfill the requirement of wastewater reclamation standard. The MBR-2 system is more economical compared with MBR-1 system. The cost of US dollars 0.10-0.16/m3 is estimated to reclaim the effluent of primary WWTP in Taiwan. The Bali Primary WWTP has the capacity of 1,320,000 cmd which is the biggest in Taiwan. The domestic wastewater of partial Taipei City and Taipei County are collected and transported to the Bali Primary WWTP. The effluent of the Bali Primary WWTP is then discharged into the ocean through two 3.8 m marine outfalls. The AO processes are installed in both MBR systems. More than 90% of the NH3-N can be removed through the AO and membrane processes. The outflow of the MBR systems (without RO) can reach the quality of COD <30 mg/l, BOD <10 mg/l, SS <5 mg/l, NH3-N <3 mg/L. The outflow of the MBR system is proposed to transport 40 km south to the Taoyuan County where four new industrial parks are to be constructed. Part of the reclaimed water is to be used on irrigation and another portion is to be sent to the industries after RO treatment.     

沣河2001—2009年水质变化特征

利用沣河沣峪、沣河口、严家渠、三里桥4个监测断面2001—2009年的水质监测资料和沣河秦渡镇的水文资料,采用季节性Kendall检验方法,对CODMn、BOD5和NH3-N的变化趋势进行分析。结果表明:中上游监测断面的水质变化趋势不显著,下游断面的CODMn、BOD5和NH3-N均呈显著减小趋势;整条河流的CODMn、BOD5和NH3-N均显著减小,年平均减小速率分别为0.5460、.330、0.031 mg/L;水质变化主要是由入河污染物量的变化引起的,受流量的影响相对较小。     

Vegetated ditches for treatment of surface water with highly fluctuating water regime

Vegetated drainage ditches (VDD) as a type of constructed wetland primarily serve to remove and store excess water associated with irrigation and storm events. Current research suggests using a VDD as an additional practice in the mitigation of surface water pollution. The VDD for water treatment of the Glinscica River was constructed in 2006. The efficiency of the system was evaluated in 2008 and 2009 regarding the reduction of SS, COD, BOD5, NH4-N, NO3-N, NO2-N, TN, ON and TP. The microbiological association developed in the VDD was analyzed with a focus on the identification and quantification of the narG gene as a denitrification indicator. This paper discusses the efficiency of pollution removal and the distribution of the narG gene within the VDD. The results showed that the highly fluctuating water regime was the main reason for the even distribution and abundance of the narG gene throughout the system, regardless of oxygen saturation or the nutrient status of the wastewater. With the exception of SS, pollutant concentrations met the permitted outflow levels.     

生态湿地在污水处理厂尾水深度处理中的应用

将生态湿地技术用于处理南通市某污水处理厂的尾水,详细介绍了处理工艺流程和设计参数,并对主要技术指标进行了分析。运行结果表明:生态湿地技术对城市污水处理厂尾水具有较好的净化效果,对COD、BOD5、NH3-N和TP的平均去除率分别达到60.1%,55.3%,76.6%,57.8%以上,出水水质达到了《地表水环境质量标准》(GB3838-2002)中Ⅲ类水的要求,有效削减了污染物的入河排放量,改善了区域水环境质量。     

河流滨岸带坡面对降雨径流的污染削减效应——以上海市樱桃河为例

选取上海市闵行区樱桃河畔具代表性的滨岸带地域,在模拟降雨过程中,设置不同坡度,不同坡长及植被条件下的对比实验。得出最优方案:坡度约为8°±0.5°,被冬青覆盖的河滨带在宽度为4~5 m时,对降雨径流的污染削减效果最佳。此时模拟地表径流平均入水质状况为,进水水质:ρ(COD)=154.7 mg/L、ρ(TP)=0.55 mg/L、ρ(NH3-N)=1.19 mg/L,出水水质:ρ(COD)=77.38 mg/L、ρ(TP)=0.29 mg/L、ρ(NH3-N)=0.69 mg/L;削减率分别为49.98%,47.27%,41.61%。试验结果为提高城市绿地规划与建设的合理性以及城市降雨径流非点源污染的控制提供参考。     

A process-dependent real-time controller for sequencing batch reactor plants: results of full-scale operation.

This paper presents results of a research project, in which a process-dependent real-time control (RTC) strategy for a sequencing batch reactor plant was realised in full-scale. The cycle controller is based on NH4 analysers, NO3 probes, TSS probes and sludge level probes. With this new RTC strategy it was possible to increase the treatment capacity by 50%. By implementation of the new controller the TN, TP and NH4-N treatment efficiency could be improved significantly, too. The treatment efficiency concerning COD is comparable.     

Comparison between a moving bed bioreactor and a fixed bed bioreactor for biological phosphate removal and denitrification

Moving bed bioreactors (MBBR) and fixed bed bioreactors (FBBR) were compared for biological phosphorus removal and denitrification. The sorption denitrification P-elimination (S-DN-P) process was selected for this study. Results indicated that all nutrients were removed by the FBBR process compared with the MBBR process: 19.8% (total COD), 35.5% (filtered COD), 27.6% (BOD(5)), 62.2% (acetate), 78.5% (PO(4)-P), and 54.2% (NO(3)-N) in MBBR; 49.7% (total COD), 54.0% (filtered COD), 63.2% (BOD(5)), 99.6% (acetate), 98.6% (PO(4)-P), and 75.9% (NO(3)-N) in FBBR. The phosphate uptake and NO(3)-N decomposition in the FBBR process during the denitrification phase were much higher than for the MBBR process despite being of shorter duration. Results obtained from this study are helpful in elucidating the practical implications of using MBBR and FBBR for the removal of bio-P and denitrification from wastewater.     

Electrolytic degradation of biorefractory organics and ammonia in leachate from bioreactor landfill.

Electrochemical oxidation was applied to treat the effluent from bioreactor landfill with leachate recirculation, characterised as poor biodegradability and high NH3-N concentration. In this study, the effluent was electrolysed in a batch reactor with Ti/TiO2-IrO2-RuO2 anode and stainless steel cathode. The oxidation of dissolved organic matter (DOM) during electrolysis was evaluated based on the evolution of molecular weight grade, hydrophilic fractionation (humic acid, fulvic acid and hydrophilic fractions), specific ultraviolet absorbance (SUVA254) and AOX. The impact of the initial NH3-N concentration on the oxidation was discussed. The results showed that at a current density of 100 mA/cm2, electrolysis time of 1.5 h and electrode gap of 1 cm, NH3-N with an initial concentration of 1.2 g/L could be completely eliminated and 56% of COD with an initial concentration of 1.2 g/L could be removed, which illustrated that the electrolysis-produced chlorine preferentially oxidised ammonia. The electrolysis mainly resulted in the degradation of humic substances and other high molecular DOM, followed by the increase of BOD/COD ratio and decline of SUVA254 of the leachate. The current efficiencies for COD and ammonia oxidation gradually decreased during the electrolysis, with the latter obviously higher than the former. At the optimal electrolysis time of 1.5 h, NH3-N could be totally removed and the BOD/COD ratio could be enhanced to 0.3, which was also favourable to control the AOX at a reasonable level.     

Performance evaluation of subsurface wastewater infiltration system in treating domestic sewage

This study was to investigate domestic treatment efficiency of a subsurface wastewater infiltration (SWI) system over time. The performances of a young SWI system (in Shenyang University, China, fully operated for one year) and a mature SWI system (in Shenyang Normal University, China, fully operated for seven years) under the same operation mode were contrasted through field-scale experiments for one year. The performance assessment for these systems is based on physical and chemical parameters collected. The removal efficiencies within the young system were relatively high if compared with the mature one: for biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), ammonia nitrogen (NH(3)-N) and total phosphorus (TP) were 95.0, 89.1, 98.1, 87.6 and 98.4%, respectively. However, the removal efficiencies decreased over time. The mean removal efficiencies for the mature SWI system were as follows: BOD (89.6%), COD (87.2%), SS (82.6%), NH(3)-N (69.1%) and TP (74.4%). The results indicate that the mature SWI system successfully removed traditional pollutants such as BOD from domestic wastewater. However, the nutrient reduction efficiencies (including NH(3)-N and TP) decreased after seven years of operation of the mature SWI system. Meanwhile, the SWI system did not decrease the receiving surface water quality.     

水质水量结合评价渭河干流(陕西段)水资源变化

为了全面掌握渭河(陕西段)干流水资源变化总体情况,本文收集2000-2008年陕西段渭河干流水文、水质监控断面的监测资料,分别从水质、水量以及两者相结合的角度分析了渭河干流的水环境状况,并重点讨论了渭河干流主要水文站径流量与COD、NH3-N污染物的同期监测浓度的相关关系。结果表明:渭河干流(陕西段)中下游水体水质为劣V类,已受到严重污染。渭河干流可利用的水资源量有所下降,其中80%以上的水资源水质为V类,不能满足水体利用的水质目标要求,渭河干流"水质型"水资源短缺的问题凸显。渭河干流上游径流量与COD、NH3-N污染物的浓度呈低相关性,随着流程变化,径流量与COD、NH3-N污染物的浓度在渭河干流的下游华县水文站已表现为中度负相关。相比较而言,渭河干流河流水量的变化对COD浓度的影响程度大于对NH3-N污染物浓度的影响。     

Combined membrane bioreactor (MBR) and reverse osmosis (RO) system for thin-film transistor-liquid crystal display TFT-LCD, industrial wastewater recycling.

In TFT-LCD industry, water plays a variety of roles as a cleaning agent and reaction solvent. As good quality water is increasingly a scarce resource and wastewater treatment costs rises, the once-through use of industrial water is becoming uneconomical and environmentally unacceptable. Instead, recycling of TFT-LCD industrial wastewater is become more attractive from both an economic and environmental perspective. This research is mainly to explore the capacity of TFT-LCD industrial wastewater recycling by the process combined with membrane bioreactor and reverse osmosis processes. Over the whole experimental period, the MBR process achieved a satisfactory organic removal. The COD could be removed with an average of over 97.3%. For TOC and BOD5 items, the average removal efficiencies were 97.8 and 99.4% respectively. The stable effluent quality and satisfactory removal performance were ensured by the efficient interception performance of the UF membrane device incorporated with biological reactor. Moreover, the MBR effluent did not contain any suspended solids and the SDI value was under 3. After treatment of RO, excellent water quality of permeate were under 5 mg/l, 2.5 mg/l and 150 micros/cm for COD, TOC and conductivity respectively. The treated water can be recycled for the cooling tower make-up water or other purposes.     

Treatment of strong nitrogen swine wastewater in a full-scale sequencing batch reactor.

Treatment of swine wastewater containing strong nitrogen was attempted in a full-scale SBR. The strongest swine wastewater was discharged from a slurry-type barn and called swine-slurry wastewater (SSW). Slightly weaker wastewater was produced from a scraper-type barn and called swine-urine wastewater (SUW). TCOD, NH4+-N and TSS in raw SSW were 23,000-72,000 mg/L, 3,500-6,000 mg/L and 17,000-50,000 mg/L, respectively. A whole cycle of SBR consists of 4 sub-cycles with anoxic period of 1 hr and aerobic period of 3 hr. The maximum loading rates of both digested-SSW and SUW were similar to 0.22 kg NH4+-N/m3/day whereas the maximum loading rates of raw SSW was up to 0.35 TN/m3/day on keeping the effluent quality of 60 TN mg/l. The VFAs portion of SCOD in raw SSW was about more than 60%. The VFAs in SUW and digested-SSW were about 22% and 15%, respectively. NH4+-N and PO4(3-)-P in SSW were removed efficiently compared to those in digested-SSW and DUW because SSW had high a C/N ratio and readily biodegradable organic. High concentration of organic was useful to enhance denitrification and P uptake. Also the amount of external carbon for denitrification was reduced to 5% and 10% of those for digested-SSW and SUW.     

Potentials and limits of a pre-denitrification/ nitrification biofilter configuration for advanced municipal wastewater treatment.

Pre-denitrification in biofilters is limited by the amount of easily degradable organic substrate, resulting in relatively high requirements for external carbon. The combination of pre-DN, N and post-DN filters is much more advisable for most municipal wastewaters, because the recycle rate can be reduced and external carbon can be saved. For minimum use of external carbon, 100-150% recycle rate should not be exceeded. Then, approximately 50-60% of the total NO3-N can be depleted in the pre-DN stage. On average, 10 g total (t) COD/g NO3-N were required in the pre-DN stage for denitrification in the pilot and full-scale plant and 0.4-0.5 kg NO3-N/(m(3)DN d) can be reached without external carbon. As only 40-70% of the COD load is eliminated in the pre-DN, the remaining COD load is removed in the nitrification stage. 1 kg COD/(m(3) d) suppresses nitrification rates by approximately 0.1 kg NH4-N/(m(3) d). For nitrification rates, > 0.5 kg NH4N/(m(3) d) at 12 degrees C not more than 2 kg COD/(m(3) d) may be eliminated in the nitrification.