Effects of gas flow rate, inlet concentration and temperature on the biofiltration of toluene vapors

In this work the variation in the elimination capacity of a biofilter as a function of the gas flow and toluene concentration was studied. A bioreactor 0.75 m high x 14.5 cm diameter was used, divided into three equal stages, using compost to support the microorganisms, and sea shells to control the pH. The biofiltration of toluene was evaluated for flows between 0.12 and 0.73 m(3)h(-1) in a concentration range of 1-3.2 gm(-3). It was observed that on increasing the toluene inlet load by 90% (from 37 to 70 gm(3)h(-1)), the conversion by the biofilter varied by only 5% (from 98% to 93%). The biofiltration system used achieved elimination capacities of up to 82 gm(-3)h(-1) for a toluene load of 100 gm(-3)h(-1).     

陶粒-沸石-活性炭组合填料生物滤池的研究

采用陶粒、沸石、活性炭填料合理组合作为曝气生物滤池的填料对高校生活污水进行处理。研究了组合填料生物滤池生物膜的培养,不同水力负荷、容积负荷和气水比对污水处理效率的影响,以及该生物滤池对生活污水的处理效果。结果表明,采用组合填料生物滤池,接种挂膜培养周期为25d,在水力负荷为2．5m3／（m2·h）,气水比3．5：1,组合填料生物滤池出水COD、BOD5、SS、NH3-N和色度平均值达到《城市污水再生利用城市杂用水水质》GB／T18920—2002水质要求。     

Biological treatment of 2,4,6-trichlorophenol (TCP) containing wastewater in a hybrid bioreactor system with effluent recycle

Due to the toxic effects of trichlorophenol (TCP) on microorganisms, biological treatment efficiencies of TCP containing wastewaters are usually low. Synthetic wastewater containing 2,4,6-TCP was biologically treated in a hybrid-loop bioreactor system consisting of a packed column biofilm and an aerated tank bioreactor with effluent recycle in order to improve COD and TCP removals. Effects of the feed TCP concentration on COD, TCP and toxicity removal performance of the system were investigated for the feed TCP between 50 and 450 mg L(-1) while the sludge age (solids retention time, SRT) and hydraulic residence time (HRT) were kept constant at 20 d and 25 h, respectively. Biomass concentrations in the packed column and in the aeration tank decreased with increasing feed TCP concentrations due to toxic effects of TCP on the organisms. Low biomass concentrations in the system at high feed TCP contents resulted in low COD, TCP and toxicity removals. Therefore, percent TCP, COD and toxicity removals decreased with increasing feed TCP concentrations especially above 400 mg L(-1). The effluent TCP concentrations were lower than 20 mg L(-1) for the feed TCP concentrations below 390 mg L(-1) resulting in TCP and COD removals above 90%. Specific rates of TCP and COD removals increased with the feed TCP due to low biomass concentrations at high TCP contents. The system should be operated at a feed TCP lower than 400 mg L(-1) in order to obtain more than 90% TCP, COD and toxicity removals under the specified experimental conditions.     

复式潜流湿地净化生活污水的试验研究

研究了新型复式潜流人工湿地对生活污水的净化效果。在不同水力负荷、季节、曝气方式等条件下经过小试试验,分析了该湿地对污染物净化效果的影响。结果表明,该系统出水水质稳定,达到《城镇污水处理厂污染物排放标准》（GB18918--2002）的一级A标准。在水力负荷184mm·d。条件下COD、NH,一N去除率最大分别可达87．2％、68．9％。冬季低温条件下对各类污染物去除率仍大于20％。正交试验分析得知,最佳运行条件是气温28．6℃、水力负荷0．184m3·m-2·d-1、水力停留时间2．4d。对比试验表明,采用预曝气方式对湿地净化效果明显优于厌氧处理。     

人工湿地技术在农村生活污水综合治理中的应用探讨

农村生活污水具有浓度低、成分复杂、生化性高的特点,以豫南某村人工湿地工程为例,介绍人工湿地组合工艺处理农村生活污水,并对污染负荷、湿地床结构、基质材料及植被选择、水力条件等设计参数进行分析。结果表明,人工湿地系统能够有效处理农村生活污水,操作管理简单,在我国农村具有很强的推广意义。     

提高曝气池污水处理能力的可行性实践

炼化企业污水场控制污泥膨胀,可以在一定限度内有效提高装置的污水处理能力。通过对大连石化公司污水场进行生产分析,在保持有机负荷F/M相对稳定的条件下,好氧生化单元的污泥浓度由设计值2000～2500mg/L,提高至3500～4000mg/L之间,进水COD去除量由设计值8880kg/d,提高到16000kg/d,使装置的处理能力提高了1.8倍。     

多项膜生物反应器在含盐废水处理中的应用

文章介绍了哈尔滨石化公司应用多项膜生物反应器处理炼化企业含盐废水。影响膜生物反应器的主要运行参数有电导率、溶解氧、COD,电导率适宜范围是3000～5000μS/cm,大于6000μS/cm微生物受到抑制,低于2000μS/cm时,去除率显著下降;一级好氧单元溶解氧适宜范围4.2～7.0mg/L或2.0～3.0mg/L,分别是好氧微生物和兼性微生物占据优势;当进水COD低于500mg/L,出水可稳定达到GB8978-1996《污水综合排放标准》二级标准(COD≤120mg/L)。     

准好氧矿化垃圾处理渗滤液的工艺参数研究

利用准好氧矿化垃圾柱，通过室内模拟试验，采用正交试验方法研究准好氧矿化垃圾柱处理渗滤液的最佳工艺参数。研究表明，本试验最佳工艺参数为水力负荷0.023L/kg矿化垃圾·d，进水周期24h，有机负荷0．33g／kg矿化垃圾·d，氨氮负荷0.028g／kg矿化垃圾·d。其中水力负荷是影响矿化垃圾柱处理效果的关键因素。     

Intermittently aerated EMMC-Biobarrel (entrapped mixed microbial cell with Bio-barrel) process for concurrent organic and nitrogen removal

The PEMMC-Biobarrel (packed-bed of entrapped mixed microbial cells with Bio-barrel) process and MEMMC-Biobarrel (moving EMMC-Biobarrel) process were investigated for enhancing concurrent organic and nitrogen removal with applied intermittent aeration. For the PEMMC-Biobarrel process, the EMMC-Biobarrel carriers were employed at a packing ratio of 20%. In the MEMMC-Biobarrel process, the EMMC-Biobarrel carriers with a packing ratio of 10% were added along with the activated sludge (AS) in the bioreactor. Three different hydraulic retention times (HRTs) of 9, 6 and 4 h were applied. Aeration was provided intermittently at time schedules of 1 h air on/1 h air off, 1 h on/1.5 h off and 1 h on/2 h off. Nitrogen removal in the PEMMC-Biobarrel system was not improved by increasing the intermittent non-aeration time period. On the other hand, the MEMMC-Biobarrel process enhanced nitrogen removal with increasing non-aeration time even though the SCOD/N(TIN) ratio decreased from 6 to 4. Significant denitrification during the aeration cycle was observed in the MEMMC-Biobarrel process. The MEMMC-Biobarrel process demonstrated the most efficient organic and nitrogen removal at an HRT of 6 h with an intermittent aeration time schedule of 1 h on/2 h off. Nitrogen removal of 80% was achieved, which was about 15% higher compared to the AS system. TCOD and SCOD removal efficiencies were 80% and 75%, respectively.     

Bioproduction of ferric sulfate used during heavy metals removal from sewage sludge

Toxic metals removal from wastewater sewage sludge can be achieved through microbial processes involving Acidithiobacillus ferrooxidans. The oxidation of ferrous ions by A. ferrooxidans, cultured in sewage sludge filtrate, was studied in both batch and continuous flow stirred tank reactors. Sewage sludge filtrate containing natural nutrients (phosphorus and nitrogen) was recovered as effluent following the dehydration of a primary and secondary sludge mixture. Batch and continuous flow stirred tank reactor tests demonstrated that A. ferrooxidans were able to grow and completely oxidize ferrous iron in a culture medium containing more than 80% (v v(-1)) sewage sludge filtrate with 10 g Fe(II) L(-1) added. Toxic levels were reached when total organic carbon in the sewage sludge filtrate exceeded 250 mg L(-1). The ferric iron solution produced in the sludge filtrate by A. ferrooxidans was used to solubilize heavy metals in primary and secondary sludge. The solubilization of Cu, Cr, and Zn yielded 71, 49, and 80%, respectively. This is comparable with the yield percentages obtained using a FeCl(3) solution. The cost of treating wastewater sewage sludge by bioproducing a ferric ion solution from sewage sludge is three times less expensive than the conventional method requiring a commercial ferric chloride solution.     

生态过滤技术去除城镇污水氨氮的研究

生态过滤工艺是一种利用由微生物和以蚯蚓为代表的微型动物共同组成的人工生态系统对城镇污水中的氨氮进行降解和代谢的新型环保技术。该工艺由生物予处理和生态过滤组合而成。当城镇污水采用适当的生物予处理 ,生态滤池的水力负荷为 3 0m3 /m2 d时 ,该工艺处理城镇污水的氨氮去除率达 58%～ 70 % ,氨氮出水浓度为 1 0～ 1 5mg/L ,可达到国家一级排放标准。该工艺还具有比活性污泥法除氮工艺节约 60 %的能耗、 37 5%的造价、管理方便和污泥产率低等特点     

生活垃圾生物反应器填埋场的试验研究--渗滤液处理技术的发展与改良

采用生物反应器填埋场消纳生活垃圾，通过改变模拟生物反应器填埋场实验垃圾柱的装填方式和运行方式，对不同垃圾柱的渗滤液水质变化特征进行分析，试验表明，生物反应器填埋场具有稳定时间短，渗滤液污染强度削减快，给后续的渗滤处理系统的设计及运行带来极大的便利。     

Aerobic treatment of palm oil mill effluent

In this study treatment of palm oil mill effluent (POME) was investigated using aerobic oxidation based on an activated sludge process. The effects of sludge volume index, scum index and mixed liquor suspended solids during the acclimatizing phase and biomass build-up phase were investigated in order to ascertain the reactor stability. The efficiency of the activated sludge process was evaluated by treating anaerobically digested and diluted raw POME obtained from Golden Hope Plantations, Malaysia. The treatment of POME was carried out at a fixed biomass concentration of 3900+/-200mg/L, whereas the corresponding sludge volume index was found to be around 105+/-5mL/g. The initial studies on the efficiency of the activated sludge reactor were carried out using diluted raw POME for varying the hydraulic retention time, viz: 18, 24, 30 and 36h and influent COD concentration, viz: 1000, 2000, 3000, 4000 and 5000mg/L, respectively. The results showed that at the end of 36h of hydraulic retention time for the above said influent COD, the COD removal efficiencies were found to be 83%, 72%, 64%, 54% and 42% whereas at 24h hydraulic retention time they were 57%, 45%, 38%, 30% and 27%, respectively. The effectiveness of aerobic oxidation was also compared between anaerobically digested and diluted raw POME having corresponding CODs of 3908 and 3925mg/L, for varying hydraulic retention time, viz: 18, 24, 30, 36, 42, 48, 54 and 60h. The dissolved oxygen concentration and pH in the activated sludge reactor were found to be 1.8-2.2mg/L and 7-8.5, respectively. The scum index was found to rise from 0.5% to 1.9% during the acclimatizing phase and biomass build-up phase.     

长庆油田生活污水回用技术研究

文章分析了目前长庆油田站场生活污水处理工艺存在的问题,对生活污水处理工艺进行了改进,采用膜生物反应器工艺处理生活污水以得到优质的中水,从而回收利用。通过对实际工程进行水质监测,COD、氨氮、浊度的去除效果好于GB 18920-2002《城市污水再生利用城市杂用水水质》中冲厕、绿化等用水要求。通过中水回用,形成"给水→利用→处理→循环利用"的中水回用模式,既节约了新鲜水,又减少了污水排放,保护了油区生态环境。     

The effects of pulverized refuse fines (PRF) as a soil material on plant growth

Pulverized refuse fines (PRF) are the residual fine screenings from refuse-derived fuel plants after the removal of metals and oversize material from domestic refuse, and the extraction of the light fraction as fuel. It appears to be a potential soil amendment, but currently it is disposed of by landfilling. The glasshouse experiment described in this paper therefore evaluated its effectiveness as a soil amendment or soil material for plant growth.PRF had a slightly alkaline pH and was high in organic carbon and soluble salts. Unamended PRF supported significantly higher yields of ryegrass than PRF mixed with a sandy soil at 2 and 10% (w/w), and was comparable to that of sewage sludge and sludge-amended PRF. On the other hand, PRF supplemented with inorganic nitrogen or phosphorus resulted in better yields than PRF alone. Despite the high C/N ratio of PRF, nitrogen recovery in ryegrass suggested that mineralization was sufficiently high to allow adequate plant uptake and sustained plant growth, although there was initial inhibition. Tissue contents of zinc, copper and cadmium from pure PRF treatment were not excessive and were lower than those from sewage sludge.High rate applications of PRF, which are desirable from the viewpoint of disposal, should not cause environmental degradation. PRF is not as good as commercial fertilizers or potting media, but it can be an excellent soil substitute in horticulture and land reclamation.     

Application of Eichhornia crassipes and Pistia stratiotes for treatment of urban sewage in Israel

The effectiveness of sewage purification by aquatic plants, such as water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes), was tested on laboratory and pilot scales. Cascade and semi-continuous pilot experiments verified that the plants are capable of decreasing all tested indicators of water quality to levels that permit the use of the purified water for irrigation of tree crops. This applies to biochemical oxygen demand (BOD), chemical oxygen demand (COD), total suspended solids (TSS), and turbidity. The laboratory-scale tests confirm the capacity of the plants to reach and hold reasonably low levels of BOD (5-7 mg L(-1)) and COD (40-50 mg L(-1)) and very low levels of TSS (3-5 mg L(-1)) and turbidity (1-2 NTU). In the experimental pilot setup, with circulation, COD decreased from 460 to 100 mg L(-1) after 2.5-4 days of treatment, while 6-7 days were required to this end without circulation. This doubled the active pond area and provided a two-level hydraulic loading (8 and 12 L min(-1)) with circulation that proved to be effective during the summer as well as the winter season. The outflow concentrations were 50-85 mg L(-1) of COD and 4-6 mg L(-1) of BOD. The results show that the use of this free water surface flow system (FWS) and its low maintenance system for treatment of urban and agricultural sewage is a viable option.     

MBBR工艺在生活污水处理装置完善项目中的应用

文章应用MBBR(流动床生物膜反应器)工艺对某石化公司生活污水处理装置进行改造,并研究影响该工艺高效脱氮的主要因素,即pH值、DO含量和污泥回流比。结果表明:实际运行中,pH值控制在7.5、DO在1～4mg/L、污泥回流比R≤3,能取得较好的脱氮效果,将氨氮降至3mg/L以下,同时,将污泥浓度维持在5～8g/L,还可在短时间内实现CODCr高去除率。实践证明,MBBR工艺在生活污水完善项目中的应用,能够有效降低污水中污染物含量,为后续深度处理系统的稳定运行提供可靠保障。     

Root penetration of sealing layers made of fly ash and sewage sludge

Fly ash and sewage sludge are suggested materials for constructing sealing layers covering mine tailings impoundments. Little is known, however, of their effect on vegetation or resistance to root penetration. We investigate: (i) the ability of different plant species to grow in sealing layers comprising fly ash and sewage sludge, (ii) the impact on plant growth of freshly hardened fly ash compared to aged and leached ash, and (iii) the plant stress response to fly ashes of different properties. A 6-mo greenhouse study using birch (Betula pendula Roth.), Scots pine (Pinus sylvestris L.), Kentucky bluegrass (Poa pratensis L.), and willow (Salix viminalis L.) demonstrated that no roots could grow into a compacted layer consisting only of ash, while a 6:4, ash-sludge mixture admitted roots into the upper part and a 1:9, ash-sludge mixture was totally penetrated (to 15 cm in depth) by roots of willow and Scots pine. Freshly hardened ash prevented root growth more effectively than aged ash did, as was observed in tests using reed canarygrass (Phalaris arundinacea L.) and pea (Pisum sativum L.). Furthermore, extracts of highly alkaline ash were more toxic to pea in a 48-h toxicity test than less alkaline ash was. However, stress responses to diluted ash extracts of lower pH, measured as enzyme capacities in dwarf bean (Phaseolus vulgaris L.), were more related to the metal and ion contents. Root penetration of sealing layers is most effectively prevented if little sewage sludge is added, and if ash of high alkalinity is chosen.     

Influence of ground tire rubber on the transient loading response of a peat biofilter

The effect of using ground tire rubber (GTR) as an adsorptive material in the removal of a 2:1:1 weight mixture of n-butyl acetate, toluene and m-xylene by using a peat biofilter under different intermittent conditions was investigated. The performance of two identical size biofilters, one packed with fibrous peat alone and the other with a 3:1 (vol) fibrous peat and GTR mixture, was examined for a period of four months. Partition coefficients of both materials were measured. Values of 53, 118 and 402 L kg(-1) were determined for n-butyl acetate, toluene and m-xylene in peat, respectively; and values of 40, 609 and 3035 L kg(-1) were measured for the same compounds in GTR. Intermittent load feeding of 16 h per day, 5 days per week working at an EBRT of 60 s and an inlet VOC concentration of 0.3 g C m(-1), resulted in removal efficiencies higher than 90% for both biofilters, indicating that the addition of GTR did not adversely affect the behavior of the bioreactor. Full removal of n-butyl acetate was obtained for both biofilters. GTR improved the removal of the aromatics in the first part of the biofilter, facilitating lower penetration of the toluene and m-xylene into the bed. A 31-day starvation period was applied and intermittent operation subsequently restarted. In both biofilters, high removal efficiencies after a re-acclimation period of two days were achieved. A shock loading test related to 1-h peaks of three- and four-fold increases in its baseline concentration (0.30 g C m(-3)) was applied in both biofilters. For the biofilter packed with the peat and GTR mixture, attenuation greater than 60% was observed in the maximum outlet concentration when compared to the biofilter packed with peat alone.     

沈抚灌渠污水预处理实验研究

以砾石为填料采用生物滤池法和以纤维束为填料采用生物接触氧化法，分别预处理沈抚灌渠污水。试验结果表明，在水力停留时间在3．5h，控制气水比分别为5：1和4：1的反应条件下，砾石填料对COD和NH3-N的平均去除率分别为53．9％和53．6％；纤维束软填料对COD和NH3-N的平均去除率分别为55．7％和47．7％。前者对COD和NH3-N的处理效果都达到了预定要求，而后者对NH3-N的处理效果没有达到要求。