A method for the measurement of biodegradable organic carbon in waters

In the last few years several methods have been proposed for determining biodegradable dissolved organic carbon (BDOC) in waters. A modification of an original method for measuring BDOC is proposed. This method is suitable for discrete samples and for measuring the biodegradability of organic compounds dissolved in water. It consists of a dynamic procedure that measures the decrease in the dissolved organic carbon (DOC) in the sample of water. The sample is recirculated through a glass column containing a biofilm attached to a novel support medium. The method has been used to study waters at different steps in a water-treatment process and to measure the biodegradability of different dissolved organic substances in water.     

浅谈饮用水生物稳定性评价指标及体系

对比分析了国内外不同生物稳定性控制指标与配水系统中水的生物稳定性关系,并分别就BDOC(可生物降解溶解性有机碳)、AOC(生物可同化有机碳)、TP(磷)以及AOC-TDWMS和用细菌生长潜力(BGP)各自的测定方法及工程研究中的应用进行比较。饮用水生物稳定性作为一个新兴研究课题尚处于探索阶段,对各控制指标的监测方法的研究和改进以及寻求更好的控制指标及体系来控制饮用水生物稳定性,具有重要的社会现实意义。     

可生物降解有机物在水厂净水工艺中的变化

以上海市两座不同水源的典型水厂为研究对象,分析了可生物降解有机物(BOM)和总有机物(以DOC表征)在水厂常规净水工艺中的变化规律.结果表明,水厂常规工艺对AOC、BDOC与DOC的去除能力均不高,且受水温影响明显,两水厂出水均为生物不稳定性饮用水;DOC主要在沉淀单元被去除,BDOC在沉淀、砂滤单元都有去除,AOC则主要在砂滤单元被去除;加氯可造成DOC(或BDOC)向AOC的转化,使出厂水AOC浓度增加,要确保出厂水的生物稳定性,必须同步削减水中BOM与总有机物的浓度.     

饮用水生物稳定性评价指标及体系

饮用水乍物稳定性的研究是近年来水处理领域的研究热点.该文对比分析了国内外不同生物稳定性控制指标与配水系统中水的牛物稳定性关系,并分别就BDOC(可生物降解溶解性有机碳)、AOC(生物可同化有机碳)、TP(磷),以及AOC-TDWMS和用细菌生长潜力(BGP)各自的测定方法及工程研究中的应用进行比较.     

饮用水AOC与BDOC测定方法的比较与评述

可同化有机碳(AOC)和生物可降解溶解性有机碳(BDOC)是饮用水生物稳定性研究的重要指标。该文简述了AOC与BDOC的含义和关系，总结了AOC与BDOC的测定技术的原理和发展，并对不同测定方法进行了比较和评述。     

动态循环法测定可生物降解溶解性有机碳

试验以葡萄糖和邻苯二甲酸作为易生物降解和难生物降解的代表有机物，研究了一种动态循环测定ＢＤＯＣ的方法，将待测水样不断循环通过生物载体反应器，使其中可生物降解有机碳充分降解，测定ＤＯＣ的变化以确定ＢＤＯＣ值。结果表明：（１）以动态循环法 ２流程和管 ＢＤＯＣ的变化显示，水源水预氯化后ＢＤＯＣ增辑３１．５８％，出厂水加氯同样使ＢＤＯＣ增加；（２）动态循环测定ＢＤＯＣ的方法有测定时间短，能评价不同水源不     

Impact of UV/H(2)O(2) advanced oxidation treatment on molecular weight distribution of NOM and biostability of water

The presence of natural organic matter (NOM) poses several challenges to the commercial practice of UV/H₂O₂ process for micropollutant removal. During the commercial application of UV/H₂O₂ advanced oxidation treatment, NOM is broken down into smaller species potentially affecting biostability by increasing Assimilable Organic Carbon (AOC) and Biodegradable Organic Carbon (BDOC) of water. This work investigated the potential impact of UV/H₂O₂ treatment on the molecular weight distribution of NOM and biostability of different water sources. A recently developed flow cytometric method for enumeration of bacteria was utilized to assess biological stability of the treated water at various stages through measurement of AOC. BDOC was also assessed for comparison and to better study the biostability of water. Both AOC and BDOC increased by about 3-4 times over the course of treatment, indicating the reduction of biological stability. Initial TOC and the source of NOM were found to be influencing the biostability profile of the treated water. Using high performance size exclusion chromatography, a wide range of organic molecule weights were found responsible for AOC increase; however, low molecular weight organics seemed to contribute more. Positive and meaningful correlations were observed between BDOC and AOC of different waters that underwent different treatments.     

Implications of organic carbon in the deterioration of water quality in reclaimed water distribution systems

Changes in water quality in reclaimed water distribution systems are a major concern especially when considering the potential for growth of pathogenic microbes. A survey of 21 wastewater process configurations confirmed the high quality effluent produced using membrane bioreactor (MBR) technology, but suggests that other technologies can be operated to produce similar quality. Data from an intensive twelve-month sampling campaign in four reclaimed water utilities revealed the important trends for various organic carbon parameters including total organic carbon (TOC), biodegradable dissolved organic carbon (BDOC), and assimilable organic carbon (AOC). Of the four utilities, two were conventional wastewater treatment with open reservoir storage and two employed MBR technology with additional treatment including UV, ozone, and/or chlorine disinfection. Very high BDOC concentrations occurred in conventional systems, accounting for up to 50% of the TOC loading into the system. BDOC concentrations in two conventional plants averaged 1.4 and 6.3 mg/L and MBR plants averaged less than 0.6 mg/L BDOC. Although AOC showed wide variations, ranging from 100 to 2000 μg/L, the AOC concentrations in the conventional plants were typically 3-10 times higher than in the MBR systems. Pipe-loop studies designed to understand the impact of disinfection on the microbiology of reclaimed water in the distribution system revealed that chlorination will increase the level of biodegradable organic matter, thereby increasing the potential for microbial growth in the pipe network. This study concludes that biodegradable organic carbon is an important factor in the microbial quality and stability of reclaimed water and could impact the public health risk of reclaimed water at the point of use.     

Formation and Removal of Biodegradable Ozonation By-Products during Ozonation-Biofiltration Treatment: Pilot-Scale Evaluation

An ozonation-biological filtration pilot-scale study was performed to evaluate the formation and removal of biodegradable ozonation by-products. The formation of aldehydes and ketoacids was found to be proportional to the DOC concentration and ozone dosage, and a strong relationship between the formation of aldehydes, ketoacids, and biodegradable dissolved organic carbon (BDOC) was observed. Four types of granular activated carbon (GAC) and one nonadsorbing medium, biolite, were employed to evaluate the performance of biofiltration for removing ozonation by-products. It was observed that GAC filters developed biological activity sooner than the biolite filter. Once developed, biofilters, either GACs or biolite, were particularly effective in the removal of aldehydes, ketoacids and BDOC.     

黄河下游某市给水管网水质生物稳定性分析

考察了黄河下游某市给水管网水质的生物稳定性。结果表明:2011年2～7月,生物可同化有机碳AOC在8.7～328.7μg/L,81.3%的检测数据AOC<100μg/L,其值随季节变化、水温升高而升高。AOC P17在AOC组成中占优势,季节变化特征较AOC NOX明显。以引黄水库作为水源、处理工艺不同的两水厂给水管网可生物降解溶解性有机碳BDOC存在差异。黄河下游城市给水管网水质生物稳定性总体水平较好,管网不同取样点细菌再生长限制性因子有差异,AOC、磷及其他无机营养元素均有可能成为限制性因子。