矿化垃圾处理渗滤液中有机污染物的GC-MS研究

以上海市老港填埋场中矿化垃圾反应床处理渗滤液为例,定性分析了该反应床进水和出水中有机污染物组分,同时半定量分析了该反应床对有机污染物的去除效果,分析结果显示:从宏观尺度上,矿化垃圾反应床很好的去除了渗滤液中的污染物质,渗滤液经过矿化垃圾反应床后,14种有机污染物得到完全去除,3种有机物的含量降低,产生1种新物质,邻苯二甲酸二辛酯在进水和出水中同时存在,从谱图上可以看出其出水浓度降低,在不同pH值萃取条件下,从进、出水谱图的对比中可以发现,进水中大部分有机污染物得到去除.     

矿化垃圾处理渗滤液中有机污染物的GC-MS研究

以上海市老港填埋场中矿化垃圾反应床处理渗滤液为例，定性分析了该反应床进水和出水中有机污染物组分，同时半定量分析了该反应床对有机污染物的去除效果，分析结果显示：从宏观尺度上，矿化垃圾反应床很好的去除了渗滤液中的污染物质，渗滤液经过矿化垃圾反应床后，14种有机污染物得到完全去除，3种有机物的含量降低，产生1种新物质，邻苯二甲酸二辛酯在进水和出水中同时存在，从谱图上可以看出其出水浓度降低，在不同pH值萃取条件下，从进、出水谱图的对比中可以发现，进水中大部分有机污染物得到去除。     

FeC内电解处理渗滤液尾水研究

根据FeC对难降解物质具有一定的还原作用,并对部分物质具有去除COD的功效,应用FeC内电解技术对经矿化垃圾生物反应床处理后渗滤液尾水进行深度处理研究,通过FeC比例、pH条件、反应时间等不同因素的小型试验确定其适宜条件,并通过L9(34)正交试验,确定如下最佳条件,反应时间5h,pH为6,FeC比例为4:1,此时出水COD能降低约100 mg/L,而对氨氮其作用不大,甚至有增加的趋势,FeC内电解反应后出水的pH值和电导率具有一定的增加趋势。     

FeC内电解处理渗滤液尾水研究

根据FeC对难降解物质具有一定的还原作用,并对部分物质具有去除COD的功效,应用FeC内电解技术对经矿化垃圾生物反应床处理后渗滤液尾水进行深度处理研究,通过FeC比例、pH条件、反应时间等不同因素的小型试验确定其适宜条件,并通过L9(34)正交试验,确定如下最佳条件,反应时间5h,pH为6,FeC比例为4:1,此时出水COD能降低约100 mg/L,而对氨氮其作用不大,甚至有增加的趋势,FeC内电解反应后出水的pH值和电导率具有一定的增加趋势.     

FeC内电解处理渗滤液尾水研究

根据FeC对难降解物质具有一定的还原作用，并对部分物质具有去除COD的功效，应用FeC内电解技术对经矿化垃圾生物反应床处理后渗滤液尾水进行深度处理研究，通过FeC比例、pH条件、反应时间等不同因素的小型试验确定其适宜条件，并通过L9（3^4）正交试验，确定如下最佳条件，反应时间，5h，pH为6,FeC比例为4：1，此时出水COD能降低约100mg／L，而对氨氮其作用不大，甚至有增加的趋势，FeC内电解反应后出水的DH值和电导率具有一定的增加趋势。     

垃圾渗滤液处理技术研究进展

介绍了渗滤液产生来源和特点,指出垃圾渗滤液是一种非常复杂的、难以生物处理的污水,并对垃圾渗滤液物理化学处理、生物处理及土地处理法进行了探讨,重点介绍了渗滤液的土地处理,包括渗滤液回灌、人工湿地法和渗滤液矿化垃圾生物反应床处理技术,指出了土地法处理垃圾渗滤液无论在技术上还是经济上比较是可行的.     

垃圾渗滤液处理技术研究进展

介绍了渗滤液产生来源和特点,指出垃圾渗滤液是一种非常复杂的、难以生物处理的污水,并对垃圾渗滤液物理化学处理、生物处理及土地处理法进行了探讨,重点介绍了渗滤液的土地处理,包括渗滤液回灌、人工湿地法和渗滤液矿化垃圾生物反应床处理技术,指出了土地法处理垃圾渗滤液无论在技术上还是经济上比较是可行的。     

垃圾渗滤液处理技术研究进展

介绍了渗滤液产生来源和特点，指出垃圾渗滤液是一种非常复杂的、难以生物处理的污水，并对垃圾渗滤液物理化学处理、生物处理及土地处理法进行了探讨，重点介绍了渗滤液的土地处理，包括渗滤液回灌、人工湿地法和渗滤液矿化垃圾生物反应床处理技术，指出了土地法处理垃圾渗滤液无论在技术上还是经济上比较是可行的。     

混凝-电化学氧化处理垃圾渗滤液MBR出水的效能研究

采用“混凝-电化学氧化”组合工艺对某垃圾填埋场中渗滤液MBR出水进行深度处理，探究了混凝工艺、电化学氧化过程中电极种类及运行参数对MBR出水中COD去除效果的影响，并讨论了混凝预处理在MBR出水电化学氧化过程中的重要意义。试验结果表明，“混凝-电化学氧化”组合工艺对垃圾渗滤液MBR出水中COD的降解效果显著。混凝预处理可去除MBR出水中68%以上的COD含量，同时可缓解电化学氧化的有机负荷，缩短电解时间，节约能耗，强化电化学氧化对水样中COD的降解效率，避免额外的深度降解工艺及成本投入，具有较好的经济环境效益。电化学氧化过程中，三种电极对该垃圾渗滤液MBR出水的处理能力大小为PbO₂>Ru系电极>Pt电极；采用Ti/PbO₂电极电解混凝处理后的MBR水样时，仅需在室温下进行，且当电流密度在50～70 A/m²时，水样中COD的去除率可达96%以上，出水COD含量可降至10 mg/L左右，处理效果更佳。     

膜生物反应器处理垃圾渗滤液研究进展

垃圾渗滤液由于污染负荷高,水质复杂,传统的活性污泥法处理难以达到相关的国家排放标准,是国内外污水处理的难题。相比于传统活性污泥法,MBR的水力停留时间(HRT)更短,有机负荷率(OLR)更高,出水稳定且有机残留低,近年来在渗滤液处理工艺中得到了广泛的应用。本文讨论了国内外膜生物反应器处理渗滤液的研究进展,对存在的问题进行了分析,提出了MBR处理渗滤液技术的发展方向。厌氧MBR在渗滤液处理和沼气生产上有很大潜力,而活性炭联用MBR在去除难降解物质和缓解膜堵塞方面表现出色。     

Treatment of Leachate by Aged-Refuse-based Biofilter

Refuse in landfills becomes stabilized or aged, as organic matter in the refuse gradually degrades and as the soluble inorganic substances dissolve during its long-term stabilization process. Within this paper, this process is referred to as mineralization and the resultant stabilized or essentially stabilized refuse is referred to as “aged refuse.” The aged refuse contains a wide spectrum and large quantity of microorganisms, which have a strong decomposition capability for refractory organic matter present in some wastewaters, such as leachate. In this study, aged refuse excavated from two to ten year old closed landfill compartments in Shanghai Refuse Landfill (SRL) was characterized in terms of particulate distribution by screening, and a biofilter consisting of ten year old aged refuse was then used for biofiltration of leachate sampled from the landfill. Typically, 400 kg of screened aged refuse with limiting diameter less than 15 mm was used as biofiltration materials in a round shaped biofilter with 80 cm inner diameter and 80 cm height. Leachate with initial chemical oxygen demand (COD), biological oxygen demand (BOD), and NH3–N concentrations of 3,000–7,000, 540–1,500, and 500–800 mg/L, respectively, was passed through the biofilter. As a result, the corresponding concentrations in the effluent were reduced to lower than 100–350, 10–200, and 10–25 mg/L, respectively, 90–99% removal for these parameters at a hydraulic load of 80–200 L/m3 refuse/day. The color of the effluent became slightly gray, in comparison with the heavy brownish color of the influent. The treatment efficiencies heavily depend on hydraulic load, BOD/COD ratios in the leachate, and preliminary treatment of the aged refuse. A variety of leachates with various BOD/COD ratios was tested. It was found that the effluent deteriorated when BOD/COD ratios were lower than 0.1–0.2. Increase of hydraulic load resulted in a decrease of removal efficiencies. Removal of stone, plastics, and glass, etc., from the aged refuse improved the treatment. A pilot test was conducted at SRL and the experimental results obtained at laboratory scale were verified.     

Potential of a Combination of UASB and DHS Reactor as a Novel Sewage Treatment System for Developing Countries: Long-Term Evaluation

A novel municipal wastewater treatment system, consisting of a combination of an upflow anaerobic sludge blanket (UASB) and down-flow hanging sponge (DHS) posttreatment unit, was continuously evaluated for more than three years with raw sewage as an influent. The system was installed at a sewage treatment site and operated at 25±3°C. This paper reports on the results of a long term monitoring of the system. The whole experimental period was divided into three distinct phases with different operating conditions. Organic pollutants were only partially removed in anaerobic UASB pretreatment unit. The remaining organics as well as nitrogenous compounds were almost completely removed by the DHS posttreatment unit. In all phases the system demonstrated removal efficiency consistently over 95% for unfiltered biochemical oxygen demand (BOD), 80% for unfiltered-chemical oxygen demand and 70% for suspended solids. The system produced an excellent effluent quality with only 4–9?mg/L of residual unfiltered BOD. Dissolved oxygen in the final effluent was 5–7?mg/L although no aeration was provided to DHS system. Moreover, excess sludge production from DHS was negligible thus eliminating secondary sludge that is troublesome to dispose off. The system also exhibited substantial stability against twofold hydraulic shock load and fourfold organic shock load. The results suggested that the proposed system may be a competitive solution for municipal sewage treatment under variable conditions.     

Comparison of Continuous and Sequencing Batch Operated Biofilters for Treatment of Gas-Phase Methyl Ethyl Ketone

Although biofiltration has been used successfully to remove and biodegrade a wide variety of gas-phase organic contaminants generated by industrial facilities and environmental remediation efforts, the ability of conventional biofilters to maintain high removal efficiency during short-term, unsteady-state, elevated loading conditions is limited. A promising alternative for improving biofilter performance during transient elevated loading conditions while minimizing the disadvantages of conventional treatment technologies is utilization of adsorption packing media and implementation of sequencing batch operating strategies. In the studies described herein, a continuous-flow biofilter (CFB) and a sequencing batch biofilter (SBB) were operated for more than 300 days to treat a methyl ethyl ketone (MEK) contaminated gas stream. The packing medium for both biofilters consisted of activated carbon coated polyurethane foam cubes. Both biofilters exhibited stable long-term performance with greater than 99% removal of the influent 106?ppmv MEK concentration during “normal” loading conditions. To assess performance during transient loading conditions, on a regular basis the influent MEK concentration of each biofilter was temporarily increased by a factor of 10 to 1,060?ppmv MEK for a duration of either 45 or 60 min. Results are presented which demonstrate how the operational flexibility of SBB systems can be utilized to minimize or eliminate contaminant emissions from biofilters during unsteady-state loading conditions. The SBB was able to remove more than 99% of the influent MEK at a transient loading rate of 380?g?m?3?h?1 and 83% of the influent MEK at a transient loading rate of 760?g?m?3?h?1. In comparison, the CFB exhibited lower MEK removal efficiency.     

Removal of EATX from Waste Gases by a Trickle-Bed Air Biofilter

The trickle-bed air biofilter performance for treating mixtures of ethylacetate (EA), toluene (T), and xylene (X) volatile organic compounds (VOCs) was evaluated under different influent VOC loadings. The EA removal efficiencies were significantly higher than those for T and X, indicating that EA is a preferred substrate in the EATX waste gas. More than 80% removal efficiencies could be achieved under influent loadings below 77 g EA∕m3∕h, 8 g T∕m3∕h, and 10 g X∕m3∕h. The trickle-bed air biofilter appears efficient for controlling EATX emission with medium EA loadings and low TX loadings. The elimination capacities of EA, T, and X for a pure VOC feed were higher than for a mixed VOC feed and the differences increased with increased influent VOC loading.     

Organic Removal of Anaerobically Treated Leachate by Fenton Coagulation

The leachate from a Hong Kong landfill, containing 15,700 mg∕L of chemical oxygen demand (COD) and 2,260 mg∕L of ammonia nitrogen (NH3–N), was first treated in a UASB (upflow anaerobic sludge blanket) reactor at 37°C. The process on average removed 90.4% of COD with 6.6 days of hydraulic retention at an organic loading rate of 2.37 g of COD∕L?day. The UASB effluent was further treated by the Fenton coagulation process using H2O2 and Fe2+. Under the optimal condition of 200 mg of H2O2∕L and 300 mg of Fe2+∕L and an initial pH of 6.0, 70% of residual COD in the UASB effluent was removed, of which 56% was removed by coagulation∕precipitation and only 14% by free radical oxidation. It is obvious that H2O2 and Fe2+ had a strong synergistic effect on coagulation. The average COD in the final effluent was 447 mg∕L. Removing each gram of COD required 0.28 g of Fe2+ and 0.18 g of H2O2.     

Four-Substrate Design Model for Single Sludge Predenitrification System

In this paper a new mathematical steady-state model specifically aimed at the design of biological phases in single sludge predenitrification systems is proposed. The model is based on the mass balance equations of four substrates (dissolved and suspended biodegradable organic matter, ammonia nitrogen, and nitrate nitrogen) and two biomasses (heterotrophic and autotrophic microorganisms). For each specific design problem, if both the influent flow composition and the kinetic parameter values are known and the effluent nitrogen compound concentrations are fixed, the model makes possible an a priori assessment of system applicability and gives the explicit expressions of the biological phase volumes. A sensitivity analysis is also presented in order to evaluate the effect of variations in the influent and effluent characteristics on the biological phase volumes.     

Monitoring of a Best Management Practice Wetland before and after Maintenance

The U.S. Environmental Protection Agency’s (USEPA) Urban Watershed Management Branch monitored a best management practice (BMP) wetland in the Richmond Creek (RC) watershed. This BMP, designated Richmond Creek #5 (RC-5), is owned and operated by the New York City Department of Environmental Protection’s as part of the Bluebelt program. During monitoring performed in 2003 and 2004, RC-5 was monitored for several water quality parameters including suspended solids (SS), chemical oxygen demand (COD), and phosphorous. Calculated SS loads demonstrated a 61% removal which is in line with the anticipated removals of 55%–57%, however, COD was not being removed from RC-5. Due to visible accumulation of sediment in the forebay and leaves throughout the BMP, maintenance activity was performed in the spring of 2005, to remove the sediment and organic matter (leaves) by vactor truck and physical labor. About four truck loads of sediment and leaf litter, estimated at 35?m3 (46 cubic yards), was removed from the site. Monitoring during the fall of 2005 measured the effects of this maintenance activity. The effluent concentrations of COD were significantly less and less variable after maintenance, and calculated influent and effluent COD loading indicated removals. The reduction in COD effluent coincided with drops in effluent phosphorous levels. Effluent SS concentrations were not significantly altered, implying RC-5 still had capacity to remove sediments before maintenance occurred. Indications are that the maintenance activity significantly reduced the COD effluent and may help communities manage phosphorous loadings.     

Biofilm Growth and Mineral Precipitation in Synthetic Leachate Columns

The results of a numerical model developed to describe the clogging of the leachate collection systems are compared with data from column experiments conducted with synthetic landfill leachate. A biofilm kinetic model is used to calculate the utilization of organic substrates (acetate and propionate) and growth of active clog material, and the substrate removal is then linked to mineral precipitation. Calculated changes in the chemical oxygen demand and Ca2+ of the effluent leachate and the porosity profiles along the length of the column show encouraging agreement with measured values. Means to obtain reasonable parameter values are presented. The favorable outcome represents completion of an essential first step toward being able to predict what controls clogging in landfill leachate collection systems.     

SBR Treatment of High COD Effluent from Bottling Plant

The feasibility of bench scale sequencing batch reactors (SBRs) in treating a bottling plant effluent is demonstrated at various influent chemical oxygen demands (CODs) ranging from 300 to over 4,000 mg∕L. The SBRs removed over 75% of the biodegradable fraction of the influent COD at a fixed react time of 5.5 h. An easy to use process model is presented to predict the temporal variations of substrate, biomass, and dissolved oxygen concentrations during the fill and react periods in SBRs. The model satisfactorily predicted effluent COD and final biomass concentrations, as well as temporal variations of COD, biomass, and dissolved oxygen throughout the fill and react cycles.     

Influent Pollutant Concentrations as Predictors of Effluent Pollutant Concentrations for Mid-Atlantic Bioretention

The water quality performance of best management practices (BMPs) has been frequently assessed by the removal efficiency metric. Recent findings show that the removal efficiency metric is flawed because it does not account for background water quality, eco-region differentiation, and background, or “irreducible,” concentrations. Additionally, the removal efficiency metric inherently assumes a definite association exists between influent and effluent pollutant concentrations. Such a relationship between influent and effluent concentrations has been minimally studied for bioretention, the most common storm-water control measure associated with low-impact development (LID). This study analyzes influent and effluent total nitrogen (TN) and total phosphorous (TP) concentrations from 11 bioretention cells in the mid-Atlantic United States. Pooled data showed only a slight association between influent and effluent TN. Essentially no relationship exists between influent and effluent TP concentration. Both findings indicate that the percent-removal metric is a faulty means of evaluating bioretention performance. Twelve general linear models (GLMs) were created where influent TN and TP were the predictors of respective effluent TN and TP concentrations. Only one GLM was considered to be “good,” defined as 67–90% of the variation in effluent concentrations being explained by respective influent concentrations (R2 = 0.72). In addition, there were two “fair” models, five “poor” models, and four “very poor” models. No “very good” models were found for TN or TP. Furthermore, as influent nutrient concentration in runoff increases, the removal efficiency increases for TN and TP. “Dirtier” influent TP concentrations were effectively reduced; conversely, “cleaner” TP influent concentrations increased, both tending toward a (possibly media-controlled) baseline effluent concentration (0.10 to 0.18??mg/l). TN effluent data also may have been tending toward a common concentration; however, the value was not as discernible.