Quantification and modeling of the elimination behavior of ecologically problematic wastewater micropollutants by adsorption on powdered and granulated activated carbon

The adsorption on powdered activated carbon (PAC) of ecotoxic or potentially ecotoxic micropollutants (ten pharmaceuticals, four X-ray contrast media, and eight industrial chemicals) present in a biologically treated municipal wastewater is studied. All but the X-ray contrast media are eliminated with high efficiency at an economically feasible PAC dosage of 10 mg/L. Based on the experimental data, the competition between the background organic matter and the micropollutant for the active sites of the adsorbent is modeled with the help of the adsorption and tracer analysis supported by the Ideal Adsorption Solution Theory. With granulated activated carbon, adsorption isotherms are determined by spiking. Based on these experimental data and modeled parameters, a lay-out of fixed-bed adsorbers may be simulated.     

Biogenic nanoscale colloids in wastewater effluents

The size, surface area, metal complexation capacity, organic pollutant sorption potential, reactivity with disinfectants, and elevated nitrogen content of biogenic organic nanoscale material (BONM) can potentially affect aquatic environments. BONM in effluents from 11 full-scale wastewater treatment plants (WWTPs), which use a range of biological processes, were characterized in two ways. First, BONM was measured by hydrodynamic size-exclusion chromatography coupled with an online organic carbon and UV detector. Second, BONM was isolated from the wastewater using rotary evaporation and dialysis and then characterized by elemental analysis, transmission electron microscopy, and Fourier transform infrared spectroscopy. The wastewaters contained 6-10 mg/L of dissolved organic carbon (DOC). BONM accounted for 5%-50% of the DOC in wastewater effluent organic matter, and the largest size fraction (>10 kDa) of organic carbon correlated with the organic carbon content determined after rotary evaporation and dialysis. Membrane bioreactor WWTPs had the lowest fraction of BONM (<10% of the DOC), followed by conventional activated sludge (10% to 30% of the DOC), with other processes (e.g., trickling filters, aerated lagoons) containing larger BONM percentages. BONM had a lower carbon to nitrogen ratio (6.2 ± 1.7) compared with the literature values for humic or fulvic acids, exhibited chemical bonds that were indicative of amides and polysaccharides, and contained fibril entangled networks. This work has important implications for operations efficiency of WWTPs, including controlling membrane fouling and release of organic nitrogen into sensitive environments.     

Nitrogen removal from wastewater using simultaneous nitrate reduction and anaerobic ammonium oxidation in single reactor

The effects of C/N ratio and total organic carbon (TOC) loading on nitrogen removal through simultaneous nitrate reduction and anaerobic ammonium oxidation in a single reactor were examined. Granular sludge taken from a methane fermentation reactor was placed in an upflow reactor and supplied with synthetic wastewater containing nitrate at a C/N ratio of 1 to grow heterotrophic denitrifying bacteria. When nitrogen removal ratio reached 30%, anammox sludge attached to nonwoven-carrier was added into the same reactor and then ammonia was added to the synthetic wastewater. Nitrogen removal ratio was markedly increased to 80-94%. In this system, nitrogen removal ratio was affected by C/N ratio and TOC loading, not by the amount of granular sludge. A stable isotopic analysis using 15N-labeled nitrate showed that N2 gas was formed by anammox reaction.     

Thermal oxidation kinetics and mechanism of sludge from a wastewater treatment plant

The organic fraction of a sludge from a wastewater biological treatment plant is characterized by the total organic carbon, TOC, content, cyclohexane and toluene extractions, and thermal desorptions in nitrogen and air flow at different temperatures. The inorganic fraction is characterized by water extraction, FT-IR spectroscopy, thermogravimetric analysis, and scanning electron microscopy/energy dispersion X-ray analysis. The thermal degradation rate of organic carbon is studied in batch experiments in air, in the 250-500 degrees C temperature range. The sample TOC is used to measure the decrease of reagent concentration with time. The TOC vs time data are well fitted by a generalized kinetic model, previously proposed for the MSWIs fly ash thermal degradation. The rate constants of the immediate carbon gasification, k2, and of the dissociative oxygen chemisorption, k1, followed by C(O) intermediate gasification, k3, together with activation and thermodynamic parameters are calculated. The rate determining step is the C(O) oxidation. The influence of desorbed or extracted organic compounds on kinetics and the role of the C(O) formation in explaining the reaction mechanism as well as the comparison with fly ash kinetics are discussed.     

低成本吸附剂处理印染废水的研究进展及发展趋势

吸附技术广泛应用于印染废水中染料的去除,目前普遍使用商业活性炭作为吸附材料,由于成本高、再生困难,限制了其应用和发展,因此研究价格低廉的新型吸附剂替代活性炭十分必要。简单介绍了工业废弃物、天然材料和生物吸附剂,并描述了它们的优点和局限性。     

Recycling of poultry process wastewater by ultrafiltration

Poultry processing plants use relatively high amount of water with an average consumption of 26.5 L/bird during primary and secondary processing of live birds to meat. The used water contains proteins, fats, carbohydrates from meat, blood, skin and feathers, resulting in much higher biological oxygen demand (BOD) and chemical oxygen demand (COD). Hence the processors are required to remove majority of the soluble and particulate matter in the wastewater prior to discharge from the plant. Treatments for poultry wastewater include screening, diatomaceous earth filtration, ozonation, and chlorine dioxide. Food safety and inspection service regulations allow reconditioned water to replace potable water in prescribed ratios. Recycling of poultry wastewater by ultrafiltration improves the quality of recycled water and provides solution to water resource limitations. Ultrafiltration is basically a pressure-driven process that separates on the basis of molecular diameter. Membrane bioreactors (MBR) that integrate biological degradation of waste products with membrane filtration are also quite effective in removing organic and inorganic contaminants as well as biological entities from wastewater. Value added products like crude proteins could be separated through ultrafiltration from poultry wastewater, subsequently reducing the chemical oxygen demand. Ongoing research in membrane separation techniques involves exploration of new membrane materials and of new module design configurations to address issues of membrane fouling and treatment of waste streams containing high suspended solids or viscous wastes.Industrial relevancePoultry processing plants use large volumes of water at different stages of the process due to set policies regarding the pathogen reduction requirements in the broiler meat. Recovery of process wastewater benefits the plant by reducing fresh water demand, wastewater volume and energy consumption. Microbial safety is the primary concern in reconditioning of process wastewater. Proteins and fats which come from carcass debris and the blood are the major pollutants in the wastewater. These materials are of high nutritional value and should be recovered. The proteins and fats are difficult to harvest by conventional procedures. From an environmental and economic point of view, ultrafiltration is an efficient technique to recondition wastewater and to recover proteins and fats from it. Importantly, this technology addressed the water quantity and quality issues that have been raised in this industry by reducing primary water use and electrical energy. Though the capital costs of ultrafiltration are higher, their life cycle costs are comparable with conventional treatments. Further, foot print of ultrafiltration could be 30–50% of conventional filters with less consumption of chemicals. Hence this paper focuses upon the potential for the use of ultrafiltration membrane processing for recycling poultry process wastewater and recovery of value added products.     

Addition of carbon sorbents to reduce PCB and PAH bioavailability in marine sediments: physicochemical tests

The addition of activated carbon as particulate sorbent to the biologically active layer of contaminated sediment is proposed as an in-situ treatment method to reduce the chemical and biological availability of hydrophobic organic contaminants (HOCs) such as polychlorinated biphenyls (PCBs) and polycyclic aromatic hydrocarbons (PAHs). We report results from physicochemical experiments that assess this concept. PCB- and PAH-contaminated sediment from Hunters Point Naval Shipyard, San Francisco Bay, CA, was contacted with coke and activated carbon for periods of 1 and 6 months. Sediment treated with 3.4 wt % activated carbon showed 92% and 84% reductions in aqueous equilibrium PCB and PAH concentrations, 77% and 83% reductions in PCB and PAH uptake by semipermeable membrane devices (SPMD), respectively, and reductions in PCB flux to overlying water in quiescent systems up to 89%. Adding coke to contaminated sediment did not significantly decrease aqueous equilibrium PCB concentrations nor PCB or PAH availability in SPMD measurements. Coke decreased PAH aqueous equilibrium concentrations by 38-64% depending on coke dose and particle size. The greater effectiveness of activated carbon as compared to coke is attributed to its much greater specific surface area and a pore structure favorable for binding contaminants. The results from the physicochemical tests suggest that adding activated carbon to contaminated field sediment reduces HOC availability to the aqueous phase. The benefit is manifested relatively quickly under optimum contact conditions and improves in effectiveness with contact time from 1 to 6 months. Activated carbon application is a potentially attractive method for in-situ, nonremoval treatment of marine sediment contaminated with HOCs.     

Removal of sulfur-organic polar micropollutants in a membrane bioreactor treating industrial wastewater

While membrane bioreactors (MBR) have proven their large potential to remove bulk organic matter from municipal as well as industrial wastewater, their suitability to remove poorly degradable polar wastewater contaminants is yet unknown. However, this is an important aspect for the achievable effluent quality and in terms of wastewater reuse. We have analyzed two classes of polar sulfur-organic compounds, naphthalene sulfonates and benzothiazoles, by liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS) over a period of 3 weeks in the influent and effluent of a full-scale MBR with external ultrafiltration that treats tannery wastewater. While naphthalene monosulfonates were completely removed, total naphthalene disulfonate removal was limited to about 40%, and total benzothiazoles concentration decreased for 87%. Quantitative as well as qualitative data did not indicate an adaptation to or a more complete removal of these polar aromatic compounds by the MBR as compared to literature data on conventional activated sludge treatment. While quality improvements in receiving waters for bulk organic matter are documented and the same can be anticipated for apolar particle-associated contaminants, these data provide no indication that MBR will improve the removal of polar poorly biodegradable organic pollutants.     

有机废水资源化研究进展

介绍了国内乳品废水、制糖废水、淀粉废水、味精废水处理技术及资源化进展。这四种废水属于高浓度有机废水，可生化性好，主要采用物化和生化方法处理。同时这些废水中含有许多有价值成分，可以开发利用，着重介绍了这几种废水在综合利用和资源化研究方面的进展。     

活性炭吸附脱除废水中2,4-二氯苯酚的研究

2,4-二氯苯酚(2,4-DCP)毒性大、难降解,是化工、农药、染料、防腐剂等行业废水中常见的有机污染物。本文以活性炭为吸附剂处理含2,4-DCP的废水,考察了pH、活性炭添加量、吸附时间、2,4-DCP浓度以及活性炭使用次数对废水处理能力的影响。实验结果表明,pH、活性炭添加量、吸附时间、2,4-DCP浓度对2,4-DCP的去除率影响显著;在293K温度下,浓度为100mg/L的2,4-DCP废水,在pH为5、活性炭添加量为50mg、吸附处理100min后,2,4-DCP的去除率可达99.5%。实验表明,含2,4-DCP的废水处理后符合国家综合污水一级排放标准,为污水处理设计、工程建设等提供了有价值的实验数据。     

我国白酒废水处理工艺探讨

白酒作为中国特有的酒产品,种类繁多,分布广泛,而白酒生产过程中会产生大量的酿酒废水。白酒酿造废水是一种高浓度有机废水,具有极高的化学需氧量（COD）和悬浮颗粒物浓度,并含有大量氮、磷等元素,且pH较低。该文简要介绍了我国白酒的一般生产工艺以及酿酒废水的排放情况和污染特征;综述了当前我国白酒酿造废水的处理现状,主要为“物化法+生物法”耦合工艺;归纳总结了我国大中型白酒厂常用处理工艺,并通过与大中型白酒厂对比,剖析了当前小型分散式白酒厂废水处理的重点与难点;同时介绍了其他白酒废水处理工艺并阐明了行业发展的方向。     

CQJ型气浮技术在思茅松制浆废水处理中的应用

介绍云景林纸废水处理工艺“物理化学处理法＋好氧生物处理法＋化学处理法”的原理,以及CQJ型超效浅层气浮在处理思茅松制浆废水中的应用及特点。     

Production of electricity during wastewater treatment using a single chamber microbial fuel cell

Microbial fuel cells (MFCs) have been used to produce electricity from different compounds, including acetate, lactate, and glucose. We demonstrate here that it is also possible to produce electricity in a MFC from domestic wastewater, while atthe same time accomplishing biological wastewater treatment (removal of chemical oxygen demand; COD). Tests were conducted using a single chamber microbial fuel cell (SCMFC) containing eight graphite electrodes (anodes) and a single air cathode. The system was operated under continuous flow conditions with primary clarifier effluent obtained from a local wastewater treatment plant. The prototype SCMFC reactor generated electrical power (maximum of 26 mW m(-2)) while removing up to 80% of the COD of the wastewater. Power output was proportional to the hydraulic retention time over a range of 3-33 h and to the influent wastewater strength over a range of 50-220 mg/L of COD. Current generation was controlled primarily by the efficiency of the cathode. Optimal cathode performance was obtained by allowing passive air flow rather than forced air flow (4.5-5.5 L/min). The Coulombic efficiency of the system, based on COD removal and current generation, was < 12% indicating a substantial fraction of the organic matter was lost without current generation. Bioreactors based on power generation in MFCs may represent a completely new approach to wastewater treatment. If power generation in these systems can be increased, MFC technology may provide a new method to offset wastewater treatment plant operating costs, making advanced wastewater treatment more affordable for both developing and industrialized nations.     

Odorous compounds in municipal wastewater effluent and potable water reuse systems

The presence of effluent-derived compounds with low odor thresholds can compromise the aesthetics of drinking water. The potent odorants 2,4,6-trichloroanisole and geosmin dominated the profile of odorous compounds in wastewater effluent with concentrations up to 2 orders of magnitude above their threshold values. Additional odorous compounds (e.g., vanillin, methylnaphthalenes, 2-pyrrolidone) also were identified in wastewater effluent by gas chromatography coupled with mass-spectrometry and olfactometry detection. Full-scale advanced treatment plants equipped with reverse osmosis membranes decreased odorant concentrations considerably, but several compounds were still present at concentrations above their odor thresholds after treatment. Other advanced treatment processes, including ozonation followed by biological activated carbon and UV/H(2)O(2) also removed effluent-derived odorants. However, no single treatment technology alone was able to reduce all odorant concentrations below their odor threshold values. To avoid the presence of odorous compounds in drinking water derived from wastewater effluent, it is necessary to apply multiple barriers during advanced treatment or to dilute wastewater effluent with water from other sources.     

退浆废水中自由基引发的聚乙烯醇交联沉淀研究

针对纺织印染工业退浆废水中含聚合度高且化学稳定性强的聚乙烯醇(PVA),是纺织工业水污染治理难点的现状,利用过硫酸盐能够引发自由基交联且氧化性强的优势,结合退浆废水高温排放的特点,使用热活化过硫酸盐体系通过自由基交联快速将PVA从废水中沉淀分离。考察了过硫酸盐投加量、反应时间、反应温度及p H值对PVA去除的影响。并利用电子顺磁共振谱、傅里叶变换红外光谱、X射线光电子能谱等对交联沉淀物进行表征分析。结果表明:在过硫酸盐投加量为10 g/L、废水温度为70℃时,处理30 min后PVA即可有效交联沉淀,化学需氧量(COD)和PVA去除率分别可达95.1%和95.6%;过硫酸钾热活化主要产生硫酸根自由基和羟基自由基,PVA被自由基夺氢产生碳自由基,碳自由基相互结合可高效交联PVA并快速沉淀。     

偶氮染料废水厌氧生物脱色强化

针对偶氮染料废水的生物降解难题,通过对比投加不同浓度的电子供体（葡萄糖）和氧化还原介体（RM）蒽醌-2,6-二磺酸钠盐和活性炭对偶氮染料的厌氧生物脱色效果的影响,探究增强偶氮染料厌氧生物脱色的条件。结果表明,投加电子供体或RM均可有效强化偶氮染料废水厌氧生物脱色：投加300 mg/L葡萄糖时脱色率可高达53.35%,投加200 mmol/L蒽醌-2,6-二磺酸钠盐时脱色率为34.59%,与投加0.6 g/L的活性炭的脱色率（35.26%）相当;投加葡萄糖时0~24 h的脱色速率最快为1.47%/h,36 h脱色效率接近最大值为46.49%;投加蒽醌-2,6-二磺酸钠盐时0~12 h的脱色速率最快为1.03%/h,60h脱色效率接近最大值为33.30%;投加活性炭时0~30 h的脱色速率最快为0.79%/h,60 h脱色效率接近最大值为33.65%。     

A comparative analysis of odour treatment technologies in wastewater treatment plants

Biofiltration, activated sludge diffusion, biotrickling filtration, chemical scrubbing, activated carbon adsorption, regenerative incineration, and a hybrid technology (biotrickling filtration coupled with carbon adsorption) are comparatively evaluated in terms of environmental performance, process economics, and social impact by using the IChemE Sustainability Metrics in the context of odor treatment from wastewater treatment plants (WWTP). This comparative analysis showed that physical/chemical technologies presented higher environmental impacts than their biological counterparts in terms of energy, material and reagents consumption, and hazardous-waste production. Among biological techniques, the main impact was caused by the high water consumption to maintain biological activity (although the use of secondary effluent water can reduce both this environmental impact and operating costs), biofiltration additionally exhibiting high land and material requirements. From a process economics viewpoint, technologies with the highest investments presented the lowest operating costs (biofiltration and biotrickling filtration), which suggested that the Net Present Value should be used as selection criterion. In addition, a significant effect of the economy of scale on the investment costs and odorant concentration on operating cost was observed. The social benefits derived from odor abatement were linked to nuisance reductions in the nearby population and improvements in occupational health within the WWTP, with the hybrid technology exhibiting the highest benefits. On the basis of their low environmental impact, high deodorization performance, and low Net Present Value, biotrickling filtration and AS diffusion emerged as the most promising technologies for odor treatment in WWTP.     

Nanomaterial transformation and association with fresh and freeze-dried wastewater activated sludge: implications for testing protocol and environmental fate

Engineered nanomaterials (ENMs) are an emerging class of contaminants entering wastewater treatment plants (WWTPs), and standardized testing protocols are needed by industry and regulators to assess the potential removal of ENMs during wastewater treatment. A United States Environmental Protection Agency (USEPA) standard method (OPPTS 835.1110) for estimating soluble pollutant removal during wastewater treatment using freeze-dried, heat-treated (FDH) activated sludge (AS) has been recently proposed for predicting ENM fate in WWTPs. This study is the first to evaluate the use of FDH AS in batch experiments for quantifying ENM removal from wastewater. While soluble pollutants sorbed equally to fresh and FDH AS, fullerene, silver, gold, and polystyrene nanoparticles' removals with FDH AS were approximately 60-100% less than their removals with fresh AS. Unlike fresh AS, FDH AS had a high concentration of proteins and other soluble organics in the liquid phase, an indication of bacterial membrane disintegration due to freeze-drying and heat exposure. This cellular matter stabilized ENMs such that they were poorly removed by FDH AS. Therefore, FDH AS is not a suitable sorbent for estimating nanoparticle removal in WWTPs, whereas fresh AS has been shown to reasonably predict full-scale performance for titanium removal. This study indicates that natural or engineered processes (e.g., anaerobic digestion, biosolids decomposition in soils) that result in cellular degradation and matrices rich in surfactant-like materials (natural organic matter, proteins, phospholipids, etc.) may transform nanoparticle surfaces and significantly alter their fate in the environment.     

梯级混凝和生物活性炭组合工艺对棉秆造纸废水的处理

采用"梯级混凝+生物活性炭(BAC)"组合工艺处理棉秆高得率制浆造纸废水二沉池出水,并对该工艺进行了最佳条件的研究。试验结果表明:梯级混凝段,在最佳投药量的基础上,一级混凝对二沉池出水COD和色度的去除率分别为30%和28%。二级混凝对COD和色度的去除率分别为60%和70%;生物活性炭段对COD和色度的去除率分别达到50%和70%。该联合工艺对棉秆高得率制浆造纸废水二沉池出水的处理有效可行,完全满足棉秆制浆造纸回用水的要求。