Rating method for evaluating distribution-system odors compared with a control.

A new sensory method was developed and tested at a full-scale water treatment plant. The method evaluates changes in aesthetic water quality during transit in the distribution system. A paired comparison format is used to determine if the odor of a distribution-system sample is different from that of a control sample. The control sample represents the "ideal" water, such as treated water leaving the plant. The method can rapidly determine whether or not a problem exists in the distribution system, and, if one does exist, it allows for characterization of the problem. Over a three-month period a 4-member odor panel evaluated 118 distribution samples by this new procedure. Among the 118 samples tested, 39 samples yielded a consensus among the analysts as to the odor characteristics of the sample; 35 were rated "not different from the control" (about 90%), and only 4 were rated "different from control" (about 10%). The 79 samples for which no consensus was generated had only slight rating differences between analysts and for odor intensity. No taste-and-odor problems were reported by consumers during the time period for this study and the method indicated that no major odor problems existed in the distribution system.     

臭味感官分析法在饮用水测定中的应用

饮用水中频频出现的臭味问题往往影响其饮用品质。由于致臭物质复杂且含量很少,不容易检测,如何定量和定性测定臭味成为目前研究的热点。臭味感官分析法是目前正在推广普及的臭味分析方法之一,包括臭味强度指标法、臭味阈值法、臭味层次分析法和臭味等级描述法,其中臭味层次分析法最具生命力,已在我国部分地区开始采用。     

Development of an odor wheel classification scheme for wastewater.

Overall, in the air pollution control field, odor concentration and intensity as well as hedonic rating have been well studied to the point where some level of standardization is being developed or is already in place. However, there has been no standardization with respect to odor quality characterization. There is now sufficient understanding of the types of odorous compounds that can arise from wastewater treatment processes to develop an odor classification scheme. This article presents the first wastewater odor wheel or classification scheme that should form the foundation for the evolution of odor quality data reporting with links to chemical causes.     

Understanding odorants associated with compost, biomass facilities, and the land application of biosolids.

Odorous water and air can result from compost, biomass facilities and land application of biosolids. Common odorous compounds from these biodegradation systems include alcohols, aldehydes, fatty acids, solvents and various sulfur and nitrogen compounds. Each odorant possesses a unique individual odor signature i.e. odor character or quality, odor threshold concentration and chemical concentration. This paper develops an initial understanding of how the volatile odorous chemicals and their relative concentrations produced are related to the total odor quality from the process by their odor threshold concentrations. The compost process is used as an example. It was estimated, that on day 1 and 7, the primary fatty acids controlling the fermented and rotten odors were butyric acid and valeric acids, individually, unpleasant and rancid odors, respectively, although acetic acid had the highest fatty acid concentration on both days. In the same way, aldehydes and ketones controlled the disappearance of the sweet odor from day 1 to 7.     

The value of an odor-quality-wheel classification scheme for wastewater treatment plants.

Each odorant possesses a unique odor signature (i.e. odor character or quality, odor threshold and chemical concentration). This paper develops an initial understanding of how the volatile odorous chemicals and their relative concentrations produced are related to the total odor quality from the process by their odor threshold concentrations and odor signatures.     

Case study of odor and indoor air quality assessment in the dewatering building at the Stickney Water Reclamation Plant

Indoor air quality (IAQ) and odors were determined using sampling/monitoring, measurement, and modeling methods in a large dewatering building at a very large water reclamation plant. The ultimate goal was to determine control strategies to reduce the sensory impacts on the workforce and achieve odor reduction within the building. Study approaches included: (1) investigation of air mixing by using CO(2) as an indicator, (2) measurement of airflow capacity of ventilation fans, (3) measurement of odors and odorants, (4) development of statistical and IAQ models, and (5) recommendation of control strategies. The results showed that air quality in the building complies with occupational safety and health guidelines; however, nuisance odors that can increase stress and productivity loss still persist. Excess roof fan capacity induced odor dispersion to the upper levels. Lack of a local air exhaust system of sufficient capacity and optimum design was found to be the contributor to occasional less than adequate indoor air quality and odors. Overall, air ventilation rate in the building has less effect on persistence of odors in the building. Odor/odorant emission rates from centrifuge drops were approximately 100 times higher than those from the open conveyors. Based on measurements and modeling, the key control strategies recommended include increasing local air exhaust system capacity and relocation of exhaust hoods closer to the centrifuge drops.     

金门水厂原水中臭味物质去除的中试研究

金门地区水库富营养化严重影响饮用水水质。夏天藻类所产生的臭味以土霉味为主。土霉味主要来自于藻类代谢物二甲基异冰片和土臭素。利用活性炭处理工艺分别使二甲基异冰片、土臭素及嗅值的去除率达92%、83%及72%;而利用臭氧一生物活性炭工艺则可使二甲基异冰片、土臭素及嗅值的去除率分别达96.3%、100%及96.7%。组合工艺可有效去除臭味物质,但清水池加氯消毒所产生的氯臭味,使嗅值无法达到台湾地区的饮用水水质标准,因此要特别注意控制加氯量。     

Ambient odour testing of concentrated animal feeding operations using field and laboratory olfactometers.

The Missouri Air Conservation Commission regulations include regulations that limit the amount of acceptable odor from confined animal feeding operations (CAFOs). The regulations concerning odor designate the use of a scentometer as a screening tool. The rules dictate that if an odor is detectable by an investigator at a dilution ratio of 5.4 using a scentometer then an air sample should be collected and sent to an olfactometry laboratory for an odor panel to determine the detection threshold and the intensity of the odor sample. The detection thresholds are determined following ASTM E679-91 and EN13725. The intensity is determined following ASTM E544-99. If the olfactometry laboratory determined the detection threshold of the sample to be above seven, then the CAFO would be in violation. If the olfactometry laboratory determined the intensity level to be above a level equivalent to 225 ppm of n-butanol, then the source of odor would be in violation. The CAFO odor rules came under scrutiny by representatives of the largest hog producer in the State of Missouri. Specifically, they argued that the detection threshold limit of seven in the CAFO portion of the rule was too low for the rule to realistically identify a violation. This paper presents the results of a study to find the appropriate regulatory level of odor as determined by laboratory olfactometry. The study took place from November 2001 to October 2002. Samples were collected from field locations that exhibited odor produced by confined animal feeding operations and from areas exhibiting no apparent odor. The odors were categorized based upon the scentometer level at which the odors were detectable, and then samples were sent to an odor evaluation laboratory for analysis by olfactometry.     

新型萤火虫算法-投影寻踪模型在区域人水和谐评价中的应用

为科学评价区域人水和谐状况,构建新型萤火虫算法(NFA)-投影寻踪(PP)评价模型。以文山州2006-2018年资料为例进行实例研究。选取8个典型测试函数对NFA进行仿真验证,并与教学优化(TLBO)等4种优化算法的仿真结果进行对比。从水资源、经济社会、生态环境3个方面遴选16个指标构建区域人水和谐度评价指标体系和分级标准,在各分级标准阈值间采用随机内插的方法生成样本构建人水和谐度评价投影目标函数,利用NFA优化求解该目标函数的最佳投影向量,构建NFA-PP模型对研究区2006-2018年人水和谐状况进行评价。结果表明:NFA寻优效果优于TLBO等4种算法,具有较好的寻优精度、极值寻优能力和全局搜索能力。NFA-PP模型对实例2006-2011年人水和谐度评价为"不和谐",2012-2016年评价为"基本和谐",2017-2018年评价为"较和谐"。2006-2018年文山州人水和谐度呈上升趋势,且上升趋势显著。     

利用剪切波速对饱和砂土地震液化的判别

现行有关抗震规范的液化判别方法大多使用标贯试验方法,最大判别深度不超过20 m,而近些年来的地震灾害调查显示超过20 m的饱和砂土深层液化现象是客观存在的。为此,基于Kayne场地液化数据库和修正的双曲线模型,建立了临界剪切波速液化判别公式,其判别成功率可达到80%以上。以西藏某水利枢纽为例,结合现行规范中的判别方法,对比分析并评价了本文剪切波速液化判别方法的适用性。结果表明:(1)对于埋深20 m以内的饱和砂层,《水力发电工程地质勘察规范》(GB 50287—2016)中规定的标贯判别方法得到的液化判别结果最为安全;(2)《岩土工程勘察规范》(GB 50021—2001)中规定的剪切波速液化临界曲线,对埋深超过20 m的饱和砂层液化判别过于保守,在高地震烈度时可导致极其密实的砂土被判别为液化,但在Ⅶ度时,该法对埋深10 m以内的浅层砂土的液化判别结果偏不安全;(3)对于高地震烈度区或者埋深超过20 m的深层液化判别来说,本文剪切波速方法既能克服《岩土工程勘察规范》(GB 50021—2001)判别方法过于保守的弊端,又能得到相对合理的液化判别结果。当场地缺少标贯数据或者需要对埋深超过20 m的砂土进行液化判别时,本剪切波速判别液化方法具有较强的实用性。     

Compost odor control using high carbon wood ash.

A pilot study on the feasibility of using high carbon wood ash to control composting odor emissions was conducted at a green material composting facility. The study's treatments consisted of adding 0%, 12.5%, and 25% high carbon wood ash by volume to green-material compost feedstock in three separate windrows. The wood ash has properties similar to activated carbon with an active surface area of 105 square metres per gram on a dry weight basis. The odorant emission data suggest that the higher percentage wood ash treatment results in the most effective control of most compost odors and that wood ash provides effective treatment of volatile fatty acids and some aldehydes and ketones. The 25% wood ash treatment resulted in more effective treatment of odors for a longer time period than the 12.5% treatment. Acetaldehyde had the highest concentration in the control (14,000 times its odor threshold concentration), was reduced by high carbon ash by over 97% but remained 386 times its reported odor threshold concentration after 14 days. Ethyl mecaptan and ammonia were produced in the process and were also over their reported human detection limits.     

广东水资源统一管理机构改革方案的研究

立足为广东水资源管理体制改革提供理论支持之目的,概要剖析了广东水资源部门分割管理的现状,并提出了广东水资源统一管理政府机构改革的3个方案: "大改方案"、"小调方案"和"协调方案".从行政效率考虑,"大改方案"和"小调方案"较优,但从可操作性的角度考虑,"大改方案"和"小调方案"劣于"协调方案".宜选择"协调方案"作为水资源统一管理省级政府机构改革的技术路线.     

Analysis of sulfur and nitrogen odorants using solid-phase microextraction and GC-MS.

An analytical method involving solid-phase micro-extraction (SPME) and gas chromatography-mass spectrometry (GC-MS) was applied to analyze biosolids odors. A selective ion monitoring (SIM)-based MS method was developed, using SPME injections of odorant standards under the full-scan mode to select the quantification and confirmation ions for each odorant. The odorants analyzed in this study include: dimethylsulfide, dimethyldisulfide, methyl mercaptan, hydrogen sulfide, carbon disulfide, trimethylamine and dimethylamine. We have used this method to quantify parts-per-billion levels of odorant vapors produced during anaerobic incubation of digested wastewater sludge. Important considerations for expedient and accurate calibration under static and dynamic flow conditions are discussed. The SPME-GC-MS method may give a positive intercept in the calibration curve, especially under static sampling conditions, which sets a practical detection limit for odor analysis.     

水源水质标准中嗅味标准的研究

在我国现有的《生活饮用水水源水质标准》(CJ3020-93)标准中并未对嗅味做定性和定量的规定。嗅味层次分析方法能够对水样中的嗅味种类以及嗅味强度做出定性和定量化的判断,通过嗅味层次分析方法以及SPME-GC/MS化学分析的结果,给出了饮用水嗅味的推荐值。按不同水源地类型对二甲基异莰醇(2-MIB)的标准进行了研究,综合考虑感官分析和化学分析结果,水厂可处理程度以及消费者可接受情况,给出2-MIB标准的推荐值,一级、二级水源地的标准推荐值为10 ng/L,三级水源地的标准推荐值为50 ng/L。二甲基异莰醇(2-MIB)嗅味标准推荐值的给出在一定程度上对水源地的划分又提供了一个参考依据,开辟了水质感官分析的新思路,为我国城市水源中2-MIB含量的划分提供了参考。     

济南鹊华水厂深度处理改造工程设计及运行分析

济南鹊华水厂以引黄调蓄水库为水源,原水存在低浊高藻高臭味等问题,水厂原有工艺难以有效处理。为适应国家《生活饮用水卫生标准》(GB 5749—2006)要求,水厂将"混凝—沉淀—过滤—液氯消毒"工艺改造为"中置式高密度沉淀—臭氧催化氧化—上向流生物活性炭吸附—V型砂滤—液氯消毒"工艺,改造后的净水工艺对有机物、臭味等特征污染物去除效果明显,出厂水水质稳定达标。     

水资源承载能力计算模型及关键问题

探讨了水资源承载能力的概念、内涵、计算模型及相关的关键问题．从前人提出的各种定义中,剖析水资源承载能力的内涵,认为“水资源承载能力”的定义应该从它的主体和客体间关系入手,考虑水资源承载能力的时间属性、空间属性和“可承载”准则．再从水资源承载能力的内涵剖析影响其大小的主要因素,包括水资源系统本身特性、人类活动能力及意识形态、定义“是否可承载”的目标．基于这些认识,提出一套区域水资源承载能力计算方法,包括“水资源承栽程度指标”计算和“水资源承载能力”计算,建立了水资源承载能力判别模型．并提出计算水资源承载能力的几个关键问题。     

微污染水库水处理工艺研究

通过中试,研究了生物预处理-常规处理-GAC(或O3-BAC)深度处理以及预加氯一常规处理-GAC(或O3-BAC)深度处理对微污染水库水的处理效果。结果表明,对于可生物降解性较好的原水,采用生物预处理可以明显地改善后续常规处理及深度处理的出水水质。对于氨氯、CODMn和UV254较高的水库水,处理工艺流程中应包括生物预处理或O3-BAC工艺。生物预处理-常规处理-GAC工艺的总处理效果好于预加氯-常规处理-O3-BAC工艺。此外,GAC能吸附氯仿、致突变物。当GAC再生周期过长时,出水的氯仿浓度高于进水,且Ames试验呈阳性。GAC的去臭有效期在16个月以上。     

基于SSO-PP模型的滇池流域水质综合评价

针对投影寻踪(PP)模型在实际应用中最佳投影方向a难以确定的不足,利用一种新型群体智能仿生算法——群居蜘蛛优化算法(SSO)搜寻PP模型最佳投影方向a,提出SSO-PP水质综合评价模型。以云南省滇池流域4个监测断面2003—2013年水质评价为例进行实例研究,选取对水体影响较大的氨氮等5项水质评价因子,利用各指标标准阈值z构造水质综合评价分级标准。结果表明①SSO-PP模型水质评价结果与单因子法评价结果基本相同,但对于断面1^#,2^#,4^#,部分年度水质的评价结果要优于单因子法评价结果1～2级。通过Kendall统计量检验,断面3^#—4^#水质改善趋势相对明显。②SSO-PP模型评价结果客观、合理,能够有效应用于水质综合评价。     

Treatment of taste and odor material by oxidation and adsorption.

Massive blooms of blue-green algae in reservoirs produce the musty-earthy taste and odor, which are caused by compounds such as 2-MIB and geosmin. 2-MIB and geosmin are rarely removed by conventional water treatment. Their presence in the drinking water, even at low levels (ng/L), can be detected and it creates consumer complaints. So those concentrations have to be controlled as low as possible in the drinking water. The removals by oxidation (O3, Cl2, ClO2) and adsorption (PAC, filter/adsorber) were studied at laboratory and pilot plant (50 m3/d) to select suitable 2-MIB and geosmin treatment processes. The following conclusions were derived from the study. Both of the threshold odor levels for 2-MIB and geosmin appeared to be 30 ng/L as a consequence of a lab test. For any given PAC dosage in a jar-test, removal efficiencies of 2-MIB and geosmin were increased in proportion to PAC dosage and were independent of their initial concentration in raw water for the tested PAC dosages. In comparison of geosmin with 2-MIB, the adsorption efficiency of geosmin by PAC was superior to that of 2-MIB. The required PAC dosages to control below the threshold odor level were 30 mg/L for geosmin and 50 mg/L for 2-MIB at 100 ng/L of initial concentration. Removal efficiencies of odor materials by Cl2, ClO2, and O3 were very weak under the limited dosage (1.5 mg/L), however increased ozone dosage (3.8 mg O3/L) showed high removal efficiency (84.8% for 2-MIB) at contact time 6.4 minutes. According to the initial concentrations of 2-MIB and geosmin, their removal efficiencies by filter/adsorber differed from 25.7% to 88.4%. For all those, however, remaining concentrations of target materials in finished waters were maintained below 30 ng/L. The longer run-time given for the filter/adsorber, the higher the effluent concentration generated. So it is necessary that the run-time of the filter/adsorber be decreased, when 2-MIB or geosmin occurs in raw water.     

土壤中硝态氮迁移转化的数值模拟研究

为了揭示不同灌溉强度下土壤中硝态氮浓度的变化规律,选取常德市典型浅层土壤为研究对象,以动态土柱淋滤试验和静态反硝化试验为基础,运用HYDRUS-1D软件建立数值模型对不同灌溉强度下硝态氮浓度的变化进行模拟分析。结果表明:当灌溉强度大于4 cm/d时,灌溉强度超过土壤下渗能力,灌溉水按下渗能力下渗,多余的水会形成地面积水,进而形成地表径流,模拟10 d各组土壤中硝态氮的浓度差异不大;当灌溉强度小于等于4 cm/d时,灌溉水全部下渗到土壤中,模拟10 d后土壤中硝态氮的浓度随灌溉强度的增加而增大。