HYDRAULIC AND ECONOMIC BENEFITS OF DOWNSPOUT DWERSION1

ABSTRACT: A downspout diversion program in an urban area is evaluated to assess the impacts on sanitary sewer flow volumes and cost effectiveness. Sanitary sewer flows and wastewater treatment cost data are compared for the five years before and 1.25 years after the downspout diversion was completed. In order to establish a cause and effect relationship between flow volumes and downspout diversion, measurements of precipitation, consumption patterns, and system loss (maintenance, fire flows, main ruptures) for the before and after time periods were obtained. The results indicate the downspout diversion contributed to a reduction of over 25 percent in the mean flow volumes within the sanitary sewer collection network during all rainfall events, with flow reductions ranging from 25 percent to 62 percent for rainfall depths between 6 mm (0.25 inches) and 25.4 mm (1.0 inches). Costs incurred for wastewater treatment were also reduced significantly, as overtime for overflow maintenance was eliminated. Downspout diversion is a viable nonstructural alternative for sthrmwater flow reduction in highly urbanized communities which may lack available space for large scale detention facilities.     

Inter-municipal cooperation for wastewater treatment: case studies from Israel

Since the beginning of the 1990s, local authorities in Israel have been engaged in promoting advanced Wastewater Treatment Plant (WWTP) projects throughout the country, resulting in the "wastewater treatment revolution" of the 1990s. These achievements are extremely important in the water-scarce country, as untreated or partially treated wastewater has become a major source of pollution of Israel's fresh-water resources, and reuse of high-quality effluents can expand the national water potential. Many of these projects are regional schemes based on a central WWTP, serving a few neighboring municipalities. This paper presents two case studies of such regional cooperation: the "Karmiel Region Union of Towns for Sewage Treatment" and the "Treatment and Reuse of Wastewater in the area of the Hadera Stream, Ltd." corporation. The findings suggest that regional cooperation can be an efficient tool in promoting advanced wastewater treatment, and has several advantages: an efficient use of limited resources (financial and land); balancing disparities between municipalities (size, socio-economic features, consciousness and ability of local leaders); and reducing spillover effects. However, some problems were reported in both cases and should be addressed.     

Wastewater Effluent,Combined Sewer Overflows,and Other Sources of Organic Compounds to Lake Champlain1

Abstract: Some sources of organic wastewater compounds (OWCs) to streams, lakes, and estuaries, including wastewater‐treatment‐plant effluent, have been well documented, but other sources, particularly wet‐weather discharges from combined‐sewer‐overflow (CSO) and urban runoff, may also be major sources of OWCs. Samples of wastewater‐treatment‐plant (WWTP) effluent, CSO effluent, urban streams, large rivers, a reference (undeveloped) stream, and Lake Champlain were collected from March to August 2006. The highest concentrations of many OWCs associated with wastewater were in WWTP‐effluent samples, but high concentrations of some OWCs in samples of CSO effluent and storm runoff from urban streams subject to leaky sewer pipes or CSOs were also detected. Total concentrations and numbers of compounds detected differed substantially among sampling sites. The highest total OWC concentrations (10‐100 μg/l) were in samples of WWTP and CSO effluent. Total OWC concentrations in samples from urban streams ranged from 0.1 to 10 μg/l, and urban stream‐stormflow samples had higher concentrations than baseflow samples because of contributions of OWCs from CSOs and leaking sewer pipes. The relations between OWC concentrations in WWTP‐effluent and those in CSO effluent and urban streams varied with the degree to which the compound is removed through normal wastewater treatment. Concentrations of compounds that are highly removed during normal wastewater treatment [including caffeine, Tris(2‐butoxyethyl)phosphate, and cholesterol] were generally similar to or higher in CSO effluent than in WWTP effluent (and ranged from around 1 to over 10 μg/l) because CSO effluent is untreated, and were higher in urban‐stream stormflow samples than in baseflow samples as a result of CSO discharge and leakage from near‐surface sources during storms. Concentrations of compounds that are poorly removed during treatment, by contrast, are higher in WWTP effluent than in CSO, due to dilution. Results indicate that CSO effluent and urban stormwaters can be a significant major source of OWCs entering large water bodies such as Burlington Bay.     

Sustainable wastewater management for small communities in the Middle East and North Africa

Accelerated expansion of wastewater services to small communities in the Middle East and North Africa (MENA) is essential in order to address serious concerns over water scarcity and pollution in addition to meeting the demand for convenience and protecting public health. Centralized and conventional wastewater systems are currently the preferred choice of planners and decision-makers in MENA. Water and funding are not available to provide these centralized conventional services to small communities. This paper presents an integrated approach to sustainable wastewater management for small communities in MENA under the severe water resources crisis. The approach calls for a paradigm shift from centralized conventional wastewater systems to decentralized wastewater systems. Management of wastewater in MENA should start at home. Wastewater generation should be reduced through a combination of domestic water conservation measures. On-site systems must be improved and monitored to control pollution and to recover water for non-potable water uses. Should the circumstances not allow the use of on-site systems, wastewater should be transported and managed through a community system applying the principles of decentralized wastewater management and using the settled sewers for wastewater transportation where appropriate. This approach will facilitate the accelerated and sustainable extension of environmentally responsible wastewater services to MENA's small communities. It offers great potential for cost reduction, accommodates the necessary domestic water conservation efforts, reduces freshwater inputs in wastewater transportation thus eliminating unnecessary demand on freshwater, reduces associated environmental risks and increases wastewater reuse opportunities.     

Fate of pathogenic microorganisms and indicators in secondary activated sludge wastewater treatment plants

This study was undertaken to investigate the removal of pathogenic microorganisms and their indicators in a laboratory scale biological treatment system that simulated the secondary treatment process of a wastewater treatment plant (WWTP). Four groups of microorganisms including bacteria, viruses, protozoa and helminths as well as the selected indicators were employed in the investigation. The results demonstrated that approximately 2-3 log10 removal of the microbial indicators was achieved in the treatment process. The log removal of Clostridium perfringens spores was low due to their irreversible adsorption to sludge flocs. The laboratory treatment system demonstrated a similar removal capability for Escherichia coli and the bacterial indicators (total coliforms, enterococci and particles <2.73 microm/L). The MS-2 bacteriophage, measured as a viral indicator, showed a lower removal than poliovirus, which may be considered as a worst case scenario for virus removal. The results of using particle profiling as an indicator for protozoa and helminths appeared to be inaccurate. The removal performance for bacterial and protozoan pathogens and their indicators in a full scale WWTP and the laboratory treatment system was compared.     

Decentralized approaches to wastewater treatment and management: applicability in developing countries

Providing reliable and affordable wastewater treatment in rural areas is a challenge in many parts of the world, particularly in developing countries. The problems and limitations of the centralized approaches for wastewater treatment are progressively surfacing. Centralized wastewater collection and treatment systems are costly to build and operate, especially in areas with low population densities and dispersed households. Developing countries lack both the funding to construct centralized facilities and the technical expertise to manage and operate them. Alternatively, the decentralized approach for wastewater treatment which employs a combination of onsite and/or cluster systems is gaining more attention. Such an approach allows for flexibility in management, and simple as well as complex technologies are available. The decentralized system is not only a long-term solution for small communities but is more reliable and cost effective. This paper presents a review of the various decentralized approaches to wastewater treatment and management. A discussion as to their applicability in developing countries, primarily in rural areas, and challenges faced is emphasized all through the paper. While there are many impediments and challenges towards wastewater management in developing countries, these can be overcome by suitable planning and policy implementation. Understanding the receiving environment is crucial for technology selection and should be accomplished by conducting a comprehensive site evaluation process. Centralized management of the decentralized wastewater treatment systems is essential to ensure they are inspected and maintained regularly. Management strategies should be site specific accounting for social, cultural, environmental and economic conditions in the target area.     

Use of artificial neural network black-box modeling for the prediction of wastewater treatment plants performance

A reliable model for any wastewater treatment plant is essential in order to provide a tool for predicting its performance and to form a basis for controlling the operation of the process. This would minimize the operation costs and assess the stability of environmental balance. This process is complex and attains a high degree of nonlinearity due to the presence of bio-organic constituents that are difficult to model using mechanistic approaches. Predicting the plant operational parameters using conventional experimental techniques is also a time consuming step and is an obstacle in the way of efficient control of such processes. In this work, an artificial neural network (ANN) black-box modeling approach was used to acquire the knowledge base of a real wastewater plant and then used as a process model. The study signifies that the ANNs are capable of capturing the plant operation characteristics with a good degree of accuracy. A computer model is developed that incorporates the trained ANN plant model. The developed program is implemented and validated using plant-scale data obtained from a local wastewater treatment plant, namely the Doha West wastewater treatment plant (WWTP). It is used as a valuable performance assessment tool for plant operators and decision makers. The ANN model provided accurate predictions of the effluent stream, in terms of biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) when using COD as an input in the crude supply stream. It can be said that the ANN predictions based on three crude supply inputs together, namely BOD, COD and TSS, resulted in better ANN predictions when using only one crude supply input. Graphical user interface representation of the ANN for the Doha West WWTP data is performed and presented.     

Risk-based evaluation of wastewater treatment projects: A case study in Niasar city,Iran

For sustainable wastewater management, it is essential to consider social, environmental, geological and technical features as well as economic feature in the decision-making process. A limitation of many of the earlier works on wastewater management is that they take into account only financial criteria to make a decision for a given problem. Moreover, the decision-makers’ (DMs) attitude to risk, or optimism degree, when faced with uncertainty is not considered. In this paper, we study the application of risk-based multi-attribute decision-making (RB-MADM) methods to achieve sustainable wastewater management. Consideration of uncertainty, value tradeoffs, and different risk attitudes of decision makers are the important features of the developed methodology. A case study on the Iranian city of Niasar is presented to illustrate how this methodology can be applied to select the most preferred alternative for wastewater management among a set of options. The most preferred option is selected with respect to nine attributes under different optimism/pessimism degrees, using six different MADM methods. The results show that the ranking of options is sensitive to the optimism degree of the DMs. The proposed approach may help policy makers to achieve sustainable wastewater management.     

Application of strategies for sanitation management in wastewater treatment plants in order to control/reduce greenhouse gas emissions

Greenhouse gases (GHG), basically methane (CH(4)), carbon dioxide (CO(2)) and nitrous oxide (N(2)O), occur at atmospheric concentrations of ppbv to ppmv under natural conditions. GHG have long mean lifetimes and are an important factor for the mean temperature of the Earth. However, increasing anthropogenic emissions could produce a scenario of progressive and cumulative effects over time, causing a potential "global climate change". Biological degradation of the organic matter present in wastewater is considered one of the anthropogenic sources of GHG. In this study, GHG emissions for the period 1990-2027 were estimated considering the sanitation process and the official domestic wastewater treatment startup schedule approved for the Metropolitan Region (MR) of Santiago, Chile. The methodology considers selected models proposed by the Intergovernmental Panel on Climate Change (IPCC) and some others published by different authors; these were modified according to national conditions and different sanitation and temporal scenarios. For the end of the modeled period (2027), results show emissions of about 65Tg CO(2) equiv./year (as global warming potential), which represent around 50% of national emissions. These values could be reduced if certain sanitation management strategies were introduced in the environmental management by the sanitation company in charge of wastewater treatment.     

废水资源化是实施可持续水资源管理的必然要求

介绍了可持续水资源管理的概念，阐述了实施可持续水资源管理的必要性。介绍了废水资源化的概念、意义及其发展历史与现状，论述了废水资源化是可持续水资源管理的必然要求。认为废水资源化管理必须充分考虑到其自身的特点。比较了废水资源化管理与普通的水资源管理的异同。     

珠江三角洲经济区污水系统设计原则

分析了珠江三角洲经济区水环境现状；阐述了城市污水分散处理与集中处理的利弊；指出污水深度处理与回用是形成良性水循环的有效途径，更是经济可持续发展的必然要求；通过对已建排水系统存在问题的分析，探讨了珠江三角洲经济开发区污水系统的设计原则，认为污水系统规划要改变传统设计方法，应方便再生水回用，由经济、技术、地理等综合因素确定排水分区、污水厂厂址与数量，选择适合各排水区域水质水量的工艺流程，预留污水厂与再生水回用管线分期发展的空间，应优先选用国产污水处理设备，尽可能维持城市河涌自然生态。     

TILE RATIONALE FOR OHIO'S DETERGENT PHOSPHORUS BAN1

ABSTRACT: Ohio signed into law a detergent phosphorus ban on March 26, 1988. This law limits the elemental phosphorus content of household laundry detergents to 0.5 percent in all 35 Lake Erie counties in Ohio by 1990. Ohio's detergent phosphorus ban will help non-compliant municipal wastewater treatment plants achieve compliance with the 1 mg/L effluent phosphorus standard. By limiting the phosphorus content of household laundry detergents, Ohio will also benefit from less phosphorus entering surface waters from combined sewer overflows, communities with treatment plant bypasses, and riparian homes with septic tanks. This is important because most of the phosphorus in laundry detergents is in the bioavailable form and Ohio's Lake Erie shoreline is particularly sensitive to Cladophora problems. When viewed in conjunction with reduced chemical costs for phosphorus removal and savings in sludge disposal costs, Ohio's detergent phosphorus ban is a pragmatic component of an international phosphorus management strategy to protect the Great Lakes.     

Point- and nonpoint-source pesticide contamination in the Zwester Ohm catchment, Germany

Reducing pesticide loads in surface waters implies identifying the pathways responsible for the pollution. The current study documents the pesticide contamination of the river Zwester Ohm, a 4917-ha catchment in Germany with 41% of the land used for crop production. Discharges and concentrations of 19 pesticides were measured continuously at three locations for 15 mo. The load detected at the outlet of the catchment amounted to 9048 g a.i. The losses represent 0.22% of the pesticides applied by the farmers. The contamination showed a seasonal pattern following the pesticide application times. The wastewater treatment plant system (WWTPS) in the catchment (two wastewater treatment plants [WWTP], 14 combined sewer overflows (CSO), four CSO tanks) emits during dry weather periods purified sewage and during storm events sewage mixed with stormwater runoff into the river. The contribution by the WWTPS to the pesticide load was defined as point-source pollution (PSP). The load was dominated by PSP with at least 77% of the total pollution. No significant interdependencies between intrinsic properties of the pesticides, hydrometeorological factors, and the loads occurring in the stream could be found. Therefore, it is not possible to predict PSP for other catchments based on the results from this study. Whereas 65% of the total load entered the river via the WWTP, a portion of 12% was attributed to the CSO. The study points out that the influence of CSO on PSP should be taken into account in future catchment studies in areas with comparable agricultural structure.     

Assessing the environmental performance of urban wastewater systems using the INSA model: application to the Algés-Alcântara wastewater system, in Portugal

Although the application of complex integrated models to wastewater systems is useful, it is often difficult to implement and not always suitable for the design of new systems or for their rehabilitation. Integrated simple approaches that allow assessing the environmental performance of urban wastewater systems may be advantageous, especially during the initial phases of the system planning process. This paper presents an original, straightforward approach that can be used for planning, design and operation of urban wastewater systems. The INtegrated Simplified Approach (INSA) combines the concepts of performance indicators with mass balances and can be applied to wastewater systems as a management support tool, particularly in situations where there is lack of data, economic limitations or time constraints. The INSA was applied to the Algés-Alcantara wastewater system to evaluate its environmental performance and to simulate the individual or combined impact of the rehabilitation measures proposed, thus defining their priority. The results clearly indicate that, despite the investment already made upgrading the wastewater treatment plant (WWTP), the proposed interventions must be implemented to ensure an acceptable environmental performance of the system. In addition, the results demonstrate the significant pollution loads present in stormwater, frequently higher than the pollution loads discharged into receiving waters during dry weather.     

Full Water‐Cycle Monitoring in an Urban Catchment Reveals Unexpected Water Transfers (Detroit MI,USA)

A goal in urban water management is to reduce the volume of stormwater runoff in urban systems and the effect of combined sewer overflows into receiving waters. Effective management of stormwater runoff in urban systems requires an accounting of various components of the urban water balance. To that end, precipitation, evapotranspiration (ET), sewer flow, and groundwater in a 3.40‐hectare sewershed in Detroit, Michigan were monitored to capture the response of the sewershed to stormwater flow prior to implementation of stormwater control measures. Monitoring results indicate that stormflow in sewers was not initiated unless rain depth was 3.6 mm or greater. ET removed more than 40% of the precipitation in the sewershed, whereas pipe flow accounted for 19%–85% of the losses. Flows within the sewer that could not be associated with direct precipitation indicate an unexpected exchange of water between the leaky sewer and the groundwater system, pathways through abandoned or failing residential infrastructure, or a combination of both. Groundwater data indicate that groundwater flows into the leaky combined sewer rather than out. This research demonstrates that urban hydrologic fluxes can modulate the local water cycle in complex ways which affect the efficiency of the wastewater system, effectiveness of stormwater management, and, ultimately, public health.     

EDUCATING RURAL COMMUNITY LEADERS IN WASTEWATER TREATMENT ALTERNATIVES1

ABSTRACT: Providing adequate wastewater treatment facilities for the citizens in small rural communities in the United States can cost millions of dollars. An educational program has been developed and conducted in Ohio to teach local officials about wastewater treatment alternatives. The five-session workshop covers wastewater treatment principles, needs assessment, system management, and resource gathering. The knowledge and skills gained by the 96 community leaders who participated in six workshops were measured using a pretest/pest test and surveys conducted during the workshops. From 25 percent to 100 percent of the participants increased their knowledge of treatment systems, alternatives, and relative costs. From 23 percent to 84 percent applied new skills, such as conducting a sanitary survey or examining treatment systems. The pretest also revealed previous knowledge of the participants in the areas of system maintenance and consultant qualifications.     

Contribution of Wastewater Treatment Plant Effluents to Nutrient Dynamics in Aquatic Systems: A Review

Excessive nutrient loading (considering nitrogen and phosphorus) is a major ongoing threat to water quality and here we review the impact of nutrient discharges from wastewater treatment plants (WWTPs) to United States (U.S.) freshwater systems. While urban and agricultural land uses are significant nonpoint nutrient contributors, effluent from point sources such as WWTPs can overwhelm receiving waters, effectively dominating hydrological characteristics and regulating instream nutrient processes. Population growth, increased wastewater volumes, and sustainability of critical water resources have all been key factors influencing the extent of wastewater treatment. Reducing nutrient concentrations in wastewater is an important aspect of water quality management because excessive nutrient concentrations often prevent water bodies from meeting designated uses. WWTPs employ numerous physical, chemical, and biological methods to improve effluent water quality but nutrient removal requires advanced treatment and infrastructure that may be economically prohibitive. Therefore, effluent nutrient concentrations vary depending on the particular processes used to treat influent wastewater. Increasingly stringent regulations regarding nutrient concentrations in discharged effluent, along with greater freshwater demand in populous areas, have led to the development of extensive water recycling programs within many U.S. regions. Reuse programs provide an opportunity to reduce or eliminate direct nutrient discharges to receiving waters while allowing for the beneficial use of reclaimed water. However, nutrients in reclaimed water can still be a concern for reuse applications, such as agricultural and landscape irrigation.     

Confronting limitations: new solutions required for urban water management in Kunming City

Despite continuous investment and various efforts to control pollution, urban water environments are worsening in large parts of the developing world. In order to reveal potential constraints and limitations of current practices of urban water management and to stimulate proactive intervention, we conducted a material flow analysis of the urban water system in Kunming City. The results demonstrate that the current efficiency of wastewater treatment is only around 25% and the emission of total phosphorous from the city into its receiving water, Dianchi Lake, is more than 25 times higher than its estimated tolerance. With regard to the crisis of water quantity and quality, the goal of a sustainable urban water environment cannot be attained with the current problem-solving approach in the region due to the technical limitations of the conventional urban drainage and treatment systems. A set of strategies is therefore proposed. The urban drainage system in Zurich is used as a reference for a potential best-available technology for conventional urban water management (BAT) scenario in terms of its low combined frequency of sewer overflow.     

污水处理厂化学除磷精确控制系统研究——以山东某污水处理厂为例

我国总磷排放标准日趋严格,污水处理厂为保证出水总磷达标,过量投加化学除磷剂,造成资源浪费.为在出水水质达标的基础上节省化学除磷剂添加量,以山东某污水处理厂为例设计了化学除磷精确控制系统.在充分考虑仪器故障潜在风险的前提下,根据进水磷酸盐负荷实时调整药剂投加量,采用"前馈+反馈"控制的模式,实现加药过程的自动化及智能化....     

Source characterization of nervous system active pharmaceutical ingredients in healthcare facility wastewaters

Nervous system active pharmaceutical ingredients (APIs), including anti-depressants and opioids, are important clinically administered pharmaceuticals within healthcare facilities. This study provides source characterization data describing the composition and magnitude of nervous system APIs present in healthcare facility wastewaters. Concentrations and mass loadings of ten nervous system APIs and three nervous system API metabolites are reported for wastewaters from a hospital, nursing, assisted living, and independent living facility within a single municipality. Concentrations of nervous system APIs ranged from non-detectable levels for alprazolam in all four facility wastewaters to a high of 290 ng/L amitriptyline in nursing facility wastewater. The summed mean concentration of all thirteen analytes ranged from 402 ng/L in independent living facility wastewater to 624 ng/L in assisted living facility wastewater. Wastewater flow rates from each facility were combined with concentration data to estimate the daily mass loading of nervous system APIs leaving each facility through wastewater discharge to the municipal sewer system. The total mass loading of all thirteen analytes for the hospital, nursing, assisted living, and independent living facility was 228, 44, 29.5, and 28.1 mg/day, respectively. The total mass loading of nervous system APIs contributed to the municipality's wastewater from all four facilities was 330 mg/day.