Evaluation of virus removal in MBR using coliphages T4

A membrane bioreactor (MBR) with gravity drain was tested for domestic wastewater for 65 days. Resultss howed that the effluent quality was excellent, and met with the reuse water standard of China (GB/T 18920-2002). Virus removal in the membrane separation process was investigated by employing coliphages T4 as a tracer. Two microfiltration membrane modules, with pore sizes of 0.22 and 0.1 μm, were used to investigate their effects on virus rejection at the transmembrane pressure of 8.5 kPa. It was found that 0.1 μm membrane had complete rejection of virus, and 0.22 μm membrane had significant rejection of virus. In the longterm operation of this MBR, no significant difference was observed between both pore sizes because the virus concentrations of the effluent in both cases were in the same order. Effluent virus concentration at steady state of MBR running was less than 2 PFU/mL. The removal ratios of coliphage T4 in MF processes were more than 10^5.5. The membrane surface deposits played an important role in the rejection of virus. The formation of cake clay on the membrane surface was the main cause of high rejection of colipbage T4 with MF of 0.22 μm.     

Diatomite Precoated Nonwoven Membrane Bioreactor for Domestic Wastewater Reclamation

Nonwoven was selected as filtration materials in submerged membrane bioreactor( MBR) for domestic wastewater reclamation. For its hydrophobic membrane surface,diatomite was precoated on nonwoven to improve membrane hydrophilicity. In the precoating stage,diatomite dynamic membrane could be formed on10 μm polyethylene nonwoven surface efficiently and effluent turbidity could be below 5 nephelometric turbidity units( NTU).The MBR system was operated steadily under gravity flow and scanning electron microscope( SEM) analysis showed that nonwoven membrane was only partially fouled at the membrane flux of 5 L/( m2·h). Average removal efficiencies of chemical oxygen demand( COD) and NH +4-N were above 86 % and 50 %,respectively. The effluent turbidity and chromaticity were below 5 NTU and 25°,respectively. Those results could meet the requirements for wastewater reuse.     

Study on performance of submerged membrane bioreactor in proteinaceous wastewater treatment

The continuous flowing experiment using a submerged membrane bioreactor (SMBR) in proteinaceous wastewater treatment was studied. The removal rate of the chemical oxygen demand (COD) was over 96.0% and the biochemical oxygen demand (BOD) was above 98.1%, the average removal rate of the total nitrogen (TN) was 61.7% ,the removal rate of NH3-N was as high as 99% ,but the removal effect of the total phosphorus (TP) was instable. The analysis under the condition of our experiments came to the conclusion that backwashing, waterpower scouting, low-pressure opexation and control of mixed liquor suspended solid (MISS) could lighten the attenuation of filtration flux in SMBR.     

Influence of solid retention time on sludge characteristics and effluent quality in immersed membrane bioreactor

Here the effect of solid retention time （SRT） on the concentration of the mixed liquor suspend solid （MLSS）, the sludge characteristics, the content of extra-cellular polymeric substances （EPS）, the viscosity of mixed liquor and effluent quality in the immersed membrane bioreactor （IMBR） was investigated. The results indicate that the increase of the EPS content is the main reason for the increase of mixed liquor viscosity, the former is positively correlated with the latter （R^2 = 0.9751）. The size distribution profile of particles in the mixed liquor presents double-peak shape at SRT more than 30 days. The filtration resistance of membrane in IMBR is mainly caused by the tiny particles and the viscosity of the mixed liquor. In this study, the extension of SRT can hardly affect the removal efficiency of Chemical Oxygen Demand （COD） and NH4^＋-N, and when SRT is below 30 days, silt density index （SDIIs） is less than 3, the effluent can be deeply treated by using reverse osmosis system （RO） or nano-filtration system （NF）. The method of controlling SRT is put forward by analyzing the relationship between SRT and the minimum generation-time of dominant bacteria （at the maximum specific growth rate under the operation temperature）.     

Completely Autotrophic Nitrogen-removal over Nitrite in Two Types of Reactors

IntroductionWastewater with high ammoniumconcentrations,suchas sludge digestion liquor,landfill leachate and piggerywastewater,are rather cost-intensive when treated withconventional methods as both the oxygen demand fornitrification and the additional COD demand fordenitrification depend onthe respective nitrogen concentrationin wastewater.As a result,a number of new techniquesconcerning nitrogen removal have been developed todecrease the high costs of energy and carbon addition.In recent ye…     

Analysis of Circumstance Influence Factors on HMBR for Waste-water Reclamation in Dwelling District

Circumstance influence factors on Hybrid Membrane Bio-Reactor (HMBR) process for the wastewater reclamation in dwelling district was analyzed. The main characteristic of this process is that sludge and nitrified effluent can be recycled automatically, which simplifies the operation of system and is beneficial to get the high removal of organics and nitrogen. Based on the analysis of circumstance influence factors, it is recommended that water temperature of about 20℃, influent pH of 6 -7 and DO of 1. 0 mg/L - 1. 5 mg/L in the aerobic compartment. Under these conditions, COD, BOD5, NH4+ -N, and TN were removed effectively in HMBR and the average removal efficiencies were 94.5%, 99.3%, 99.4% and 84.7%, respectively. SS and coliforms were both below the detection limits in the permeate of UF membrane module, and turbidity was less than 1NTU. The treated effluent meets the Miscellaneous Domestic Water Quality Standard (CJ25.1-89), and can be reused multipurposely such as watering of green belts, cleaning a     

Evaluation of humic acid removal by a flat submerged membrane photoreactor

A flat submerged membrane combined with a TiO 2 /UV photocatalytic reactor (FSMPR) was employed in batch mode to remove humic acid (HA). HA removal efficiency was characterized by UV 254 absorbance, UV-vis spectra, dissolved organic carbon (DOC) concentration, specific UV absorbance (SUVA), and trihalomethane formation potential (THMFP). The FSMPR process was effective in removing more than 86% of DOC and nearly 100% of UV 254 absorbance, while the THMFPs of samples were reduced to < 19 μ g/L after 150 min of treatment. In addition, changes in transmembrane pressure (TMP) with and without UV were evaluated; TiO 2 /UV was effective at controlling membrane fouling by HA. Analysis of the molecular weight (MW) distributions and three-dimensional excitation-emission matrix (EEM) fluorescence spectra of HAs revealed that the effectiveness in membrane fouling control is a result of changes in HA molecular characteristics. The TiO 2 /UV photocatalytic reactor caused the degradation of high MW, hydrophobic humic-like molecules to low MW, hydrophilic protein-like molecules, although this fraction was not completely removed during 150 min of treatment and was less responsible for membrane fouling.     

Application of immobilized psychrotrophs in ICCBR to treat domestic wastewater and its microbiological investigation

To guarantee the efficiency of biotreatment of domestic wastewater in chilly season, six high efficient cold-adapted microorganisms were isolated, and identified as Zoogloea, Aeromonas, Flarobacterium, Micrococcus, Bacillus, Pseudomonas. These cold-adapted microorganisms with 63.67% Chemical Oxygen Demand (COD) removal efficiency higher than that of mesophiles at low temperature were immobilized on soft polyurethane foams and applied to internal circulation compound bioreactor (ICCBR) to treat domestic wastewater. In an experiment period of 12 months, the treatment efficiency, ecological factors, sludge physicochemical properties, and microbiology were studied. Results showed that the average COD removal efficiency in the ICCBR was 85.79% between 4℃ and 10℃ in winter, and 86.66% in the whole year, and COD of systemic effluent was below 60 mg•L⁻¹ which could achieve the first-degree B discharge standard of pollutants in China for municipal wastewater treatment plant. The reduction in microfauna and biomass on carriers could be associated with the seasonal temperature transients, the concentrations of protozoa and metazoan decreased from 110000±30000 microorganisms/mL sludge in summer to 35000±20000 microorganisms/mL sludge in winter, and biomass on carriers increased in the beginning and slightly reduced in the end.     

Practice of High Concentration Sludge for Efficient Nutrient Removal from Municipal Sewage

ECOSUNIDE is a new activated sludge process based on the sludge concentration optimization theory.With it,we carried out a high sludge concentration by changing influent mode and distributing carbon source in a reasonable way,which can improve the ecological superiority of nitrification and denitrification for the growth of phosphorous accumulating organisms(PAOs)and nitrifiers and raised the nutrient removal efficiency of municipal sewage treatment plants.In 2007,we adopted this technique in Linyi Sewage Treatment Plant in Shandong Province,China.After the reconstruction,we achieved the high efficiency of nutrient removal with low investment under the dynamic load of the secondary sewage treatment plant.The effluent water qualities meet the classⅠ-A criteria specified in Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant(GB 18918-2002)and the rest effluent indexes meet the classⅠ-B criteria.Besides,we have above 20% operating cost cut by stopping the internal reflux without power charge increased and any new pool structures built.     

Composition and Accumulation of Fouling during Leachate Reverse Osmosis Membrane Treatment in both a Typical Incineration Plant and a Landfill

Reverse osmosis(RO) membrane process has been extensively used for leachate treatment both in incineration plants and landfills. However, operation and maintenance costs caused by membrane pollution limit the wide application of RO membrane.In order to further understand membrane fouling, this study analyzes the influent, effluent, concentrated liquid pollutants and membrane fouling of typical waste incineration plants and landfills in Chongqing, a city in the west of China based on the comparis...     

Application of Constructed Wetlands on Wastewater Treatment for Aquaculture Ponds

A group of constructed wetlands （CWs） were applied to the recirculating aquaculture system. This study assessed the performance of CWs in treating the aquaculture wastewater, examined the water quality condition of aquaculture ponds and the growth and the survival rate of ＂target＂ species （Ictalurus punctatus and Megalobrama amblycephala）. The results showed that CWs were effective on reducing the concentrations of 5-day biochemical oxygen demand （BOD5, at 70.5%）, total suspended solids （TSS, at 81.9%）, chlorophyll a （Chl-a, at 91.9%）, ammonium （NH4^＋, at 61.5%） and nitrate nitrogen （NOa-N, at 68.0%）. Effect of CWs on phosphate （PO43 -P） removal was relatively lower （at 20.0%）. The concentrations of BODs, TSS, Chl-a, NH4^＋ and TN, TP in the recirculating culture pond were significantly lower than that in the control pond（ p〈0.05 ）. CWs could help to increase total yield, survival rate of the ＂target＂ species and significantly decrease feed conversion ratio （ p〈0.05 ）.     

电催化氧化处理垃圾渗滤液

以复极性固定床电解槽为反应器,利用CuO-CeO₂/γ-Al₂O₃多相催化剂取代传统反应器的绝缘填料,构建电催化氧化体系。采用XRD、SEM对CuO-CeO₂/γ-Al₂O₃进行表征,考察了槽电压、pH、气体流量和极间距等因素对垃圾渗滤液降解的影响。结果表明,该体系对渗滤液具有较好的催化降解效果。当槽电压为15.0V、pH为中性、气体流量为0.08m³/h、极间距为3.0cm时,垃圾渗滤液COD和NH⁺₄-N的去除率分别达到93.7%和100%。在处理垃圾渗滤液的过程中,体系运行稳定,经过20次反复实验,降解效果仍能维持在70%以上。在电催化氧化体系的作用下,垃圾渗滤液中的难降解有机污染物被直接矿化或降解为小分子有机物;而NH⁺₄-N则主要被氧化为氮气和水。     

Optimization of Four Kinds of Constructed Wetlands Substrate Combination Treating Domestic Sewage

Based on the static and dynamic experiments, this paper has analyzed the adsorbing capacity for domestic wastewater pollutant （COD, NH4^＋-N and TP） of four kinds of constructed wetlands substrate which were fly ash, hollow brick crumbs, coal cinder and activated carbon pellets in single and combined condition. In the static experiments, the adsorbing capacity of four substrates all grew as the adsorbing dose increased. In adsorbing COD, each substrate＇s adsorbing capacity rises with the adsorbing dosage. Simultaneously, experiments show that all the adsorption of the four kinds of substrate for COD, NH4^＋-N and TP follows the Freundich Rule. The dynamic experiment demonstrated that the adsorbing capacity of combined substrates is bigger than that of single substrate. Fly ash in combination with small coal cinder adsorbs COD the best, while it takes in NH4^＋-N and TP the best when working with hollow brick crumbs. The combination of the two raises the removal rates up to 89% and 81% respectively. Given high cost and low adsorbing effect, activated carbon is not a suitable candidate for constructed wetlands substrate.     

Treatment efficiency of integrated vertical-flow constructed wetland for saline wastewater

The integrated vertical-flow constructed wetland(IVCW) was simulated with three suits of designed experiment columns planted with Kandelia candel.Units A,B and C were irrigated with sewage of different salinity(A:10‰ B:20‰,C:30‰),respectively.The removal rates of dissolved organic carbon(DOC),NH3-N and NO3--N dropped 90.4%-48.6%,80.2%-40.3% and 84.8%-60.9%,respectively,when salinity increases from 10‰ to 30‰.The removal rate of TP increased 14%-31.2%,oppositely.A 20-day inflow salinity drastic change shock affective trial was done on units D and E.Unit D was used as a control and irrigated with saline sewage(20‰).Unit E was irrigated with sewage with low salinity(5‰) as a salinity drastic change shock on the third and fourth days.DOC,NH3-N and NO3--N removal efficiency of unit E showed a three-stage process of change,"rapidly decrease,increase beyond the normal standard,and then back to the normal standard".TP removal value was negative during the 2-day shock period.     

化肥厂高浓度氨氮废水的处理和回用

在实验室规模研究了通过生成鸟粪石（磷酸铵镁, MAP）去除氨氮工艺条件的影响. 加入磷酸和MgO产生MAP沉淀, pH值对其影响很大, pH值为9.0时氨氮去除效果最好. PO₄^3-, Mg²⁺, NH₄⁺的摩尔比为1 ∶1.5 ∶1时, 氨氮去除率较大并且可较好地回收氨生成鸟粪石. 此外, 物料的加入次序严重影响氨氮的去除. 两步沉淀工艺氨氮去除率达99.1%, 氨回收率为80.1%.     

不同分子量DOM对垃圾渗滤液生物处理组合工艺中DBP和DEHP去除率的影响

采用小型生物处理组合工艺(上流式厌氧污泥床+曝气生物滤池+缺氧反应器+膜生物反应器, UASB+ BAF+ANO+MBR)处理老龄垃圾渗滤液, 考察了邻苯二甲酸二丁酯(DBP)和邻苯二甲酸二(2-乙基己基)酯(DEHP)两种内分泌干扰物在组合工艺中的去除, 以及与渗滤液中溶解性有机质(DOM)去除的关系。结果表明, 组合工艺对DBP和DEHP的去除率可分别达到92.9%和95.2%, 且与DOM腐殖化作用(即腐殖质的芳香性和分子量)密切相关。溶解性有机碳(DOC)主要分布在分子量为1~100 kDa的有机组分中, 此时腐殖质的芳香性较强, DBP和DEHP的浓度也较高。经过工艺处理后, 该组分的DOC和芳香性有效降低, 相应两种污染物的去除效果也更为明显。渗滤液原水及各工艺段中DOC与DBP及DEHP浓度的正相关性, 表明二者之间相互作用更有利于污染物的有效去除。     

长龄期简易填埋条件下污泥基本性质的变化

我国曾经有大量的污泥被随意弃置形成了许多简易污泥填埋场,简易填埋的污泥不受控制的堆放在自然环境中,其性质会随着时间发生变化。本文通过对江苏省某化工企业已经简易填存20年陈污泥的取样分析,发现经过多年的堆存,降解简易填埋陈污泥中的有机质含量仍高于50%;污泥中的pH值维持在8.5～9.0,适合产甲烷菌的生存条件;污泥中的含水率大多在90%以上,且水位线在污泥坑表层0～30cm变动,下部都呈厌氧饱和状态。该简易填埋场中老污泥中重金属Zn和Mn总量较高,但浸出量和渗沥液中的含量都很低,表明重金属不是污泥简易填埋场的主要污染物。渗沥液中COD、BOD₅、TN、NH₄-N、TP大多超标,表明简易污泥填埋场中的主要污染类型为有机污染。简易填埋污泥的渗透系数在10-8cm/s数量级,水分排出困难,不适合采用真空预压或堆载排水加固的方法对场地进行加固施工。     

流型、植物种类和基质厚度对人工湿地去除废水中氨氮的影响

实验模拟人工湿地,以沙、土混合物为基质,比较了水平潜流和垂直流、不同植物、不同基质厚度对氨氮(NH_4~+-N)处理效果的影响,并分别进行了分析。实验表明,水平潜流和垂直流NH_4~+-N去除率分别达到59%和68%,垂直流人工湿地处理效果较好的原因是垂直流为硝化创造了有利的条件。金边吊兰、金钱草、绿萝对NH_4~+-N的平均去除率依次为46%、60%和70%,分析认为根系是影响NH_4~+-N去除效果的主要因素。以金钱草做湿地植物,基质厚度为6 cm时去除效果最好,最大去除率达到74%,表明基质厚度与植物根系长度相适应时,NH_4~+-N的去除效果最佳。研究结果为深化湿地去除NH_4~+-N的理论研究和应用推广提供了支撑。     

Iron fractions in the apoplast of intact root tips of Zea mays L. seedlings affected by nitrogen form

The effects of ammonium (NH₄⁺-N ) and nitrate ( NO₃^--N ) were examined on Fe fractions and FeCN (ferricyanide) reductase activity in intact root tips (0—3 cm) of young maize (Zea mays L. cv. Lenz) in solution culture by using short-term experiment under controlled Fe deficiency conditions (containing high HCO₃^- concentration in preculture solution). The results showed that Fe(Ⅱ) concentrations in root tip apoplast of maize were only 20—40 nmol/g FW which accounted for 7%—13% of total Fe. Most of Fe in root tips existed as Fe(Ⅲ) compounds. Imposition of the roots to NH₄⁺-N or NO₃^--N for 60 min led to an increase of Fe(Ⅱ) in root tip apoplast. NH₄⁺-N led to an increased concentration of Fe(Ⅱ) and exchangeable Fe (Fe(Ⅱ) and Fe (Ⅲ)) in root tips, while NO₃^--N increased FeCN reductase activity. The relationship between pH and Fe fractions, FeCN reductase activity was also discussed.     

Sanitary Sewage Treatment with Jet Inner-loop Bioreactor

0　IntroductionThejetloopreactorhasthecharacteristicsofbothjetandloopflow .Ononehand ,theairsuckedinisdispersedintosmallgasbubblesbecauseoftheshearingforcecausedbythehighvelocityjet,producinganincreasedinterfacialcontactbe tweengasandliquid ,thusthemasstransferefficiencyisin creased .Ontheotherhand ,aregularloopflowisformedbecauseofmutualimpetusofbothjetandair lift,thusdramaticallyim provestheperformancesofmixture ,diffusion ,masstransferandheattransferofthematerial.Withoutmechanicdriving ,the…