高级氧化技术降解水中药物及个人护理品的研究进展

目前,药物和个人护理品(PPCPs)在城市污水厂出水和水环境中频繁检出,已经引起了越来越多的关注.常规的污水处理工艺、饮用水处理工艺对PPCPs的降解都极其有限.高级氧化技术能高效降解PPCPs,且降解后其生化性大幅提高.全面阐述了03/H<,2>O<,2>、TiO<,2>光催化氧化、UV/H<,2>O<,2>、Fen...     

The disinfection of sewage treatment plant effluents using ultraviolet light

The discharge of chlorinated wastewaters may result in acute toxicity to the aquatic ecosystem. This toxicity is due to chlorine residuals and to chlorinated organics formed during chlorination. An alternative method to chlorination for effluent disinfection is ultraviolet light irradiation. Kills of more than 99% have been obtained for coliform, fecal coliform, fecal streptococci and heterotrophic bacteria by irradiating secondary effluents from conventional activated sludge sewage treatment plants with ultraviolet light (254nm). Laboratory scale treatment studies of ultraviolet sterilization as a method of reducing the toxicity of municipal effluents and producing effluents of acceptable bacterial quality is reported.     

Ozone Application for the Improvement of UASB Reactor Effluent. II. Toxicity Evaluation

In order to improve the effluent from domestic sewage treatment through an anaerobic process in an upflow anaerobic sludge blanket reactor (UASB), CETESB - The Environmental Protection Agency for Sao Paulo State, and FILSAN - Equipamentos e Sistemas S/A, developed a joint program to study the effectiveness of ozonation of the effluent as a post-treatment process. As the effluents treated by this system could contain toxic chemicals, Daphnia similis toxicity tests were applied. Two ozonation conditions were evaluated: (1) contact time of 30 min, mean ozone application dosage of 15.9 mg/L; (2) contact time of 50 min, mean ozone application of 16.7 mg/L. Toxicity reduction occurred for all samples but one. The ozonation system eliminated the residual toxicity associated with the effluent treated by the UASB reactor.     

Biodegradation of synthetic detergents evaluation by community trials: I. Linear alkylbenzene sulphonates

The biodegradability of a number of linear alkylbenzene sulfonates (LAS) has been evaluated by field trials with a trickling filter sewage plant serving a small community. All the LAS material examined showed a satisfactory order of biodegradability. In all the LAS materials examined, aeration of the sewage effluent resulted in further biodegradation to a degree corresponding to 96% to 99% degradation of the LAS present in the settled sewage. The results of laboratory scale biodegradation tests are largely in agreement with those obtained in the field trials. However, with tests of the simple open bottle type, such as the test of the U.K. Standing Technical Committee on Synthetic Detergents, misleading indications of low biodegradability may sometimes be obtained on products of higher molecular weight. Such products do not appear to acclimatize sufficiently rapidly to bacteria under the conditions of the open-bottle test. Under practical sewage treatment conditions, or with tests which simulate these, a high order of biodegradation is obtained. There were only minor differences in biodegradability between an LAS derived from paraffins and those derived from cracked wax olefins.     

Ecotoxicology Study of Various Homologues of Methyl Ester Sulfonates (MES) Derived from Palm Oil

Methyl ester sulfonate (MES) is an anionic surfactant derived from palm oil through sulfonation of fatty acid methyl esters. Due to limited ecotoxicological data on MES, this study was initiated to evaluate the ecotoxicological properties of MES and its impact to the environment. The respirometric method (OECD 301F) was used to monitor the biodegradation of various homologues of MES over 28 days. The algae growth inhibition test (OECD 201) was conducted to assess the effects of palm‐based MES towards green algae by exposing exponentially‐growing cultures of Pseudokirchneriella subcapitata (P. subcapitata) to five concentrations of MES with maximum concentrations of 100 mg/L. Results showed all MES samples were readily biodegradable, where the biodegradability of each homologue surpassed 60% within 28 days. It was also observed that the longer the carbon chain length of MES, the solubility and the biodegradability rate decreased. The ecotoxicity of C12 and C14 MES towards P. subcapitata after 72 h of experiment showed no inhibition of algae growth in C12 MES while, the growth of algae decreased as the concentration of C14 MES increases. The EC₅₀ value for C14 MES and C16 MES towards green algae was >100 and >10 mg/L, respectively. It can be concluded that C12 and C14 MES were practically non‐toxic towards P. subcapitata and the toxicity increased with an increase in chain length of the surfactant (EC₅₀ value decreases). Therefore homologues of palm‐based MES are not expected to cause environmental concern due to their biodegradability and low toxicity in the aquatic environment.     

Ozone-Based Decomposition of Main Endocrine Disruption Chemicals in Sewage Effluent

In order to decompose endocrine disruption chemicals (EDCs) in sewage effluent, ozone based oxidation of nonylphenol (NP), bisphenol A (BPA) and 17β-estradiol (E2) was investigated. Experimental results showed that these EDCs were decomposed easily even in the presence of other organic substances of TOC 5 mg/L. The simulation using kinetic constants obtained from the experiments indicated that these EDCs in sewage effluent were removed to below the detection limit with an amount of ozone consumed less than 0.5 mg/L. Ozonation also reduced the estrogenic activity and the aquatic acute toxicity of these EDCs solution. From these results it was concluded that ozonation was very effective in decomposing these EDCs in sewage effluent.     

EVALUATION OF UV/O3 AND UV/H2O2 PROCESSES FOR NONBIODEGRADABLE COMPOUNDS: IMPLICATIONS FOR INTEGRATION WITH BIOLOGICAL PROCESSES FOR EFFLUENT TREATMENT

Poorly biodegradable compounds reduce the efficiency of biological effluent treatment processes. These are often encountered in pharmaceutical and speciality chemical industries. Advanced oxidation technologies (AOT) are appropriate for the conversion of such compounds into biodegradable entities. Tetrahydrofuran, 1,4-dioxane, and pyridine are heterocyclic compounds that are known to be recalcitrant and nonbiodegradable. AOT were investigated for the destruction of these model compounds. Two forms of AOT, UV-O₃ and UV-H₂O₂, were studied. UV-H₂O₂ treatment resulted in higher biodegradability for tetrahydrofuran; UV-O₃ treatment resulted in higher biodegradability for 1,4-dioxane. For pyridine, neither treatment improved biodegradability. For efficient integration of AOT with biological processes for effluent treatment, it is necessary to evaluate the AOT with multiple objectives, such as level of destruction of target compound, level of reduction in COD, and enhancement of biodegradability. Due to the presence of multiple pollutants in real effluents and in AOT, kinetics of oxidation elucidated with single compounds is unlikely to be useful.     

小城镇一体化污水处理站工程设计实例

云南省某小城镇污水来源主要为生活污水,具有水量较小、可生化性好、悬浮物浓度较高等特点,设计采用地埋式一体化PASG污水处理工艺,该工艺主要由两级构成,第一级为厌氧生化处理,第二级为综合生化处理。工程运行结果表明:出水CODCr、BOD5、SS、NH3-N、TN、TP的平均质量浓度分别为45、11.5、8.0、11.75、14.5、0.75 mg/L,出水水质能稳定达到GB 18918—2002《城镇污水处理厂污染物排放标准》中一级B排放标准的要求。介绍了污水处理工艺流程,给出了主要构筑物设计参数及投资运行成本。     

Biodegradability and aquatic toxicity of glycoside surfactants and a nonionic alcohol ethoxylate

The environmental properties of three glycoside surfactants and one alcohol ethoxylate were examined by standardized laboratory methods. All of the surfactants biodegraded extensively in aerobic screening tests and may be assumed to approach 100% removal in aerobic wastewater treatment plants, except in cases of high loadings or otherwise exceptional conditions. Anaerobic biodegradability tests showed that an ethyl glycoside monoester (EGE) and a linear alkyl polyglycoside (APG) were both mineralized (>70%) under methanogenic conditions. In contrast, a branched APG resisted anaerobic degradation, while the alcohol ethoxylate was partially mineralized by anaerobic bacteria. The EGE surfactant was most rapidly mineralized in aerobic and anaerobic biodegradability tests. None of the surfactants inhibited respiration in activated sludge at the highest concentration tested (200 mg/L). Tests with aquatic organisms showed increasing toxicity in the following order: branched APG<EGE<linear APG<alcohol ethoxylate. Negligible aquatic toxicity was observed for the branched APG, while the alcohol ethoxylate was highly toxic to examined organisms. This evaluation demonstrates that considerable variation in biodegradability and toxicity responses can be seen within structurally related glucose-based surfactants.     

Effect of Ozone Pretreatment on Biodegradability Enhancement and Biogas Generation Potential From Biomethanated Distillery Effluent

The study evaluates the effect of ozone pretreatment on biodegradability enhancement of biomethanated distillery effluent. Results revealed that ozone pretreatment led to biodegradability index (BI = BOD/COD) enhancement up to 0.58 along with COD, color and toxicity reduction of up to 33%, 25% and 40%, respectively. Anaerobic digestion of pretreated effluent resulted in favorable biogas generation with methane content, yield and COD reduction of up to 62%, 39 mL/g COD and 57%, respectively. Kinetics of biogas generation determined by modified Gompertz model indicated methane production potential and production rate of 48.08 mL/g COD and 8.085 mL/g COD.day respectively under optimal conditions.     

Two step sequential treatment of pulp and paper mill effluent by Cryptococcus albidus and Emericella nidulans var. nidulans in 2L bioreactor

A number of studies had shown biological treatment of pulp and paper mill effluent. However, almost all the studies have focused on reduction in physical and chemical parameters. Toxicity analysis, though very important, has been neglected. Thus in this study genotoxicity along with colour and lignin content were studied. Treatment of effluent, generated at the pulping stage in pulp and a paper mill, was done using two fungal strains, Cryptococcus albidus and Emericella nidulans var. nidulans, in sequential manner in 2 L bioreactor. Two different treatments were given. In treatment (I) effluent was first treated by C. albidus (stage A) and this treated effluent was further treated by E. nidulans var. nidulans (stage B). In treatment (II) effluent was first treated by E. nidulans var. nidulans (stage C) and this treated effluent was further treated by C. albidus (stage D). Treatment (I) was more efficient than treatment (II) with 71%, 51%, 44% and 70% reduction in colour, lignin, COD and genotoxicity, respectively. Class distribution of comets also showed that treatment (I) was more efficient than treatment (II). Colour content showed very good correlation (r² = 0.99) with effluent toxicity. The effluent treatment process (I) can be scaled up for industrial use. © 2011 Canadian Society for Chemical Engineering     

Biodegradability of nonionic surfactants: Screening test for predicting rate and ultimate biodegradation

Environmental water quality evaluations of raw materials in consumer products occupy a position of critical importance in many industries throughout the world. The rapid growth and diversity of the household detergent market requires continuous consideration of new materials needed to meet the demands of new, improved and modified products. As household cleaning products are normally disposed of as a component of domestic sewage, surface active compounds, including nonionic surfactants, would reach surface waters only as a part of a sewage effluent and would be subject to the same degree of biological treatment as the balance of the waste. For this reason, evaluations of such new materials include an environmental assessment in which biodegradability testing of organic materials is an important first step. Biodegradability characteristics of nonionic surfactants, as a class, are generally more difficult to ascertain because of wide structural diversity and a usual lack of functional groups. Such determinations usually involve intricate and laborious test methods which necessitate development of analytical techniques for each degradation product of a given material. A method has been developed, modified and used in our laboratory, that provides, after reasonable opportunity for biological acclimation, a measure of the rate and degree of ultimate biodegradation (conversion to CO₂ and H₂O). This method, which uses simple equipment, has been used to assess the biodegradability of a wide variety of nonionic surfactants, without necessitating the development of specific analytical methods for each surfactant under consideration. Additionally, this method can be adapted to measure degradation under conditions of anaerobiosis or low temperature.     

Biodegradation and Ecotoxicity of Branched Alcohol Ethoxylates: Application of the Target Lipid Model and Implications for Environmental Classification

With the advent of global regulations for safer detergent and an emphasis on a shift toward more environmentally friendly formulations, the environmental profile of surfactant chemistries have moved to the forefront of product formulation and design. The two cornerstones of surfactant environmental profiles are the ability to biodegrade in the natural environment and the ecological hazard profile. The objectives of this article are to describe biodegradation and aquatic toxicity data for a series of branched oxo-alcohol ethoxylate (AEO) surfactants; to apply the target lipid model (TLM) for deriving model-based threshold hazard concentrations (HC5) of AEO; and, finally, to accurately determine aquatic classifications for AEO surfactants for use in regulatory classification frameworks. Biodegradation results indicate a high level of biodegradability of branched AEO, with C8–C13-rich oxo-alcohols with 1–20 mol of ethoxylate meeting the readily biodegradable criteria. Results from acute and chronic toxicity tests indicated comparable or lesser aquatic toxicity versus linear AEO structures previously reported in the literature. The TLM model, applied a priori, resulted in good agreement with acute toxicity data (RMSE = 0.49) and is comparable to the root mean square errors (RMSE) previously determined for other narcotic chemicals (RMSE = 0.46–0.57). Model errors for invertebrates and fish were smaller than those for algae, with the TLM systematically overpredicting acute and chronic classification of two of seven branched AEO. Furthermore, TLM-predicted HC5 values were determined to be sufficiently conservative, with 100% of observed chronic data (N = 79) falling above the HC5 threshold values, providing a useful tool for the risk assessment of AEO.     

New accelerated test for rapid measurement of detergent biodegradability

A new accelerated biodegradation test has been developed in order to determine rapidly the biodegradability of detergents. Natural river water is fortified with additional microorganisms isolated from sewage effluent by continuous centrifugation to remove residual detergent. This increases the reproducibility between different samples of river water and decreases seasonal effects. Using detergents of different chemical structures, this accelerated procedure gave the same biodegradable results as obtained with the usual river die-away test. However, such data can now be obtained in as little as ten days or less. Multiple test results are presented showing the rate and degree of biodegradation of representative test detergents and the reproducibility between different series of tests with the same compound. Examples are given showing that the extent and completeness of biodegradability of the test compounds depends on the degree of branching.     

Microbial and toxic evaluation of raw and treated olive oil mill wastewaters

BACKGROUND: Olive oil mill wastewaters (OMW) from a three‐phase system were treated in a laboratory‐scale continuous stirred tank reactor (CSTR) for hydrogen production. Microbiological and physicochemical characterizations of raw and anaerobically treated olive oil mill effluents were performed. Toxicity assessment was also conducted in order to determine the impact of residual waters on the aquatic environment. RESULTS: Pseudomonas aeruginosa that has the ability to utilize phenolic compounds was isolated in raw OMW, along with several gram‐negative bacteria (Serratia odorifera, Enterobacter cloacae and Aeromonas hydrophila). The dominant species in the untreated effluent appears to be Enterobacter cloacae, whereas in the treated effluent it is Citrobacter braakii. Phenols, pH, NO^?₂, total dissolved solids (TDS) and conductivity were the main parameters related to the observed toxicity. CONCLUSION: A significant differentiation in the microbiological flora was detected between treated and untreated effluents whereas the microbial communities were correlated to the toxicity test results, pointing to the need for further research regarding identification of the microbial flora. This can improve the treatment processes to optimize management of OMW for environmentally safe discharge. Copyright © 2010 Society of Chemical Industry     

Catalytic wet air oxidation of olive oil mill effluents: 4. Treatment and detoxification of real effluents

Olive oil mill wastewater (OMW) generated by the olive oil extraction industry constitutes a major pollutant, posing severe environmental threats. It contains a high organic load and phytotoxic and antibacterial phenolic compounds which resist biological degradation. Platinum and ruthenium supported titania or zirconia were studied in the catalytic wet air oxidation (CWAO) of OMWs in a batch reactor and in a continuous trickle-bed reactor. CWAO experiments at 190 °C and 70 bar total air pressure confirmed the effective elimination of the TOC (total organic carbon) and of the phenolic content of actual diluted OMW. Simultaneously, toxicity towards Vibrio fischeri was reduced and a decrease in phytotoxicity occurred. The ruthenium catalysts were found stable over a long period of operation in a trickle-bed reactor.The biodegradability of the oxidized waste has been enhanced and this study also examined the feasibility of coupling CWAO and an anaerobic digestion treatment. The pretreatment of the OMW in the presence of a ruthenium catalyst reduced considerably the total phenolic contents of the wastewater, and produced an effluent suitable to be treated by anaerobic treatment with increased biomethane production compared to the untreated effluent.     

Toxicity Assay in Kraft E1 Effluent Treated by Ozone: Algae Growth Inhibition and Cytotoxicity in V79 Cells

The efficiency of an ozonation process in the degradation of the Kraft E₁ effluent was evaluated. The investigation was focused on the reduction of chemical oxygen demand, total phenols, color and the absorbance at 254 nm. The chronic toxicity was evaluated by growth inhibition of algae Selenatrum capricornutum and cytotoxicity evaluation of effluents samples by determination of the nucleic acid content (NCA) endpoint. After 60 minutes of ozonation, COD and UV₂₅₄ only reached 21% and 34% efficiency reduction. Total phenols and color were more rapidly removed (at 10 minutes of treatment). The results showed that the chronic toxicity (Selenastrum capricornutum algae) decreases for all effluent doses studied. The cytotoxicity assay indicated that toxic compounds were not generated by the ozonation process.     

Biodegradability of poly(vinyl acetate) containing a pyridinium group

An attempt has been made to give biodegradability to poly(vinyl acetate) by partial modification of the chemical structure. Poly(vinyl acetate) containing a small amount of N-benzyl-4-vinylpyridinium chloride (PVAc-co-VPC) and that containing 16 mol % of methyl acrylate and a small amount of the pyridinium group (PVAc-co-MA-co-VPC) showed significant degradation when placed in an aeration tank of sewage works. Control polymers possessed of no pyridinium group did not show significant degradation under these conditions, and the extent of weight reduction during the treatment increased with the content of the pyridinium group. The weight reduction exhibited an uppermost limit after 7 days of the treatment, and the pyridinium group disappeared from the polymer during the early period. Incorporation of the pyridinium group into poly(vinyl acetate) appeared to have improved the biodegradability. Gel permeation chromatographic analysis showed that the low molecular weight fraction was more easily degraded than was the high molecular weight fraction. In the degradation of PVAc-co-MA-co-VPC, the unit of methyl acrylate was more easily removed than that of vinyl acetate. © 1995 John Wiley & Sons, Inc.     

Fettalkoholsulfate – Die ökologische Absicherung einer wichtigen Gruppe von Waschmitteltensiden

Fatty Alcohol Sulfates – The Ecological Evaluation of a Group of Important Detergent Surfactants The biodegradability and ecotoxicological properties of natural raw materials based fatty alcohol sulfates were extensively investigated. These surfactants displayed very fast and virtually complete biodegradation with respect to primary (MBAS) loss) as well as ultimate degradability (mineralization abd assimilation). This pertains also to the partially poorly soluble tallow alcohol sulfate as was shown by radiolabelling. In addition, complete anaerobic biodegradability was proved in a simulation test for sludge digestion. The effect concentrations determined in acute, subacute and chronic toxicity tests with bacteria, algae, daphniae and fish prove fatty alcohol sulfates to be surfactants of relatively low ecotoxicity, i. e. they are innocuous in the realistic environmental concentration range. This conclusion was supported by results obtained in models of aquatic biocenoses (microcosm, ecological system “sewage treatment plant – receiving water”). Thus, fatty alcohol sulfates can be unequivocally classified as “environmentally compatible” on the basis of the presented ecological data.     

进水条件对小型一体化装置处理污水效果的影响

针对小型一体化农村生活污水处理装置存在运行稳定性不高、处理效果难以保障等问题,研究了不同进水条件对小型一体化装置处理效果的影响,结果表明:有厨房污水作为进水来源且于前端增设化粪池的装置对COD、NH₄⁺-N和TN的平均去除率分别达85.3%、85.2%和75.4%,出水主要三项指标达到江苏省DB32/T 3462-2018的一级B标准,这是因为厨房用水含有较多易被微生物利用的物质,是BOD的主要来源;污水流经化粪池进行厌氧水解反应后污水的可生化性得以提升,研究成果应用性强且投资成本低,为农村生活污水一体化处理装置的高效稳定运行提供参考。