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• Sewage treatment deficits for forecasted rural and urban populations computed for India. • Scenario analysis to aid urban planners and decision-makers plan sustainable sewage treatment. • Life cycle costs computed considering land, capital, operation and maintenance cost. • Investing in land for natural treatment systems beneficial than energy-intensive treatment. • Lowered greenhouse gas emissions due to natural and hybrid treatment systems. Sewage treatment involves a trade-off of land vs. energy and the location of installing Sewage Treatment Plants (STPs) strongly impacts the decisions regarding treatment technologies. In the wake of rapid urbanization, deteriorating freshwater quality and water scarcity, it is crucial to plan adequate and low-cost sewerage infrastructure that can improve the quality of life in rural and urban areas. The present work involves a novel life cycle analysis through six scenarios generated from a holistic perspective that can aid urban planners and urban local bodies in planning the sewage treatment facilities in their cities, towns or villages. Instead of planning sewerage infrastructure for a long-term period of thirty years, it is suggested to create and operate the STPs only for the upcoming decade. Further, owing to the drawbacks of mechanized and natural treatment systems, adopting a mix of these treatment approaches in planning infrastructure is suggested and the benefits of implementing the same are quantified and discussed. Implementing these strategies results in almost 30 % cost savings and 40 % reduction in greenhouse gas emissions, hence, investing in land for natural treatment systems is suggested instead of incurring heavy electricity bills for mechanized treatment systems. The land cost significantly affects the decision-making regarding treatment technology selection; hence, the variation in the life cycle cost of different sewage treatment approaches is assessed for varying land rates in India. [Display omitted] [ABSTRACT FROM AUTHOR]

We present a second-generation wastewater treatment inventory model, WW LCI 2.0, which on many fronts represents considerable advances compared to its previous version WW LCI 1.0. WW LCI 2.0 is a novel and complete wastewater inventory model integrating WW LCI 1.0, i.e. a complete life cycle inventory, including infrastructure requirement, energy consumption and auxiliary materials applied for the treatment of wastewater and disposal of sludge and SewageLCI, i.e. fate modelling of chemicals released to the sewer. The model is expanded to account for different wastewater treatment levels, i.e. primary, secondary and tertiary treatment, independent treatment by septic tanks and also direct discharge to natural waters. Sludge disposal by means of composting is added as a new option. The model also includes a database containing statistics on wastewater treatment levels and sludge disposal patterns in 56 countries. The application of the new model is demonstrated using five chemicals assumed discharged to wastewater systems in four different countries. WW LCI 2.0 model results shows that chemicals such as diethylenetriamine penta (methylene phosphonic acid) (DTPMP) and Diclofenac, exhibit lower climate change (CC) and freshwater ecotoxicity (FET) burdens upon wastewater treatment compared to direct discharge in all country scenarios. Results for Ibuprofen and Acetaminophen (more readily degradable) show that the CC burden depends on the country-specific levels of wastewater treatment. Higher treatment levels lead to lower CC and FET burden compared to direct discharge. WW LCI 2.0 makes it possible to generate complete detailed life cycle inventories and fate analyses for chemicals released to wastewater systems. Our test of the WW LCI 2.0 model with five chemicals illustrates how the model can provide substantially different outcomes, compared to conventional wastewater inventory models, making the inventory dependent upon the atomic composition of the molecules undergoing treatment as well as the country specific wastewater treatment levels. [ABSTRACT FROM AUTHOR]

We report the development and application of a user-friendly, scenario-based decision support tool (TechSelect 1.0). The objective of the study focuses on implementation of the ‘scenario-based’ multiple attributes decision-making (MADM) approach recently proposed by Kalbar et al. (2012a) . The tool incorporates multiple scenarios to deal with complex decision-making situations typically encountered in urban, suburban and rural areas. The scenario-based decision-making implemented through the tool reduces complexity in the selection of the appropriate wastewater treatment technology. It also uses a life cycle sustainability assessment framework for assessing technologies from environmental (life cycle assessment), economic (life cycle costing) and social (various sustainability indicators) perspectives. In addition, a user-friendly computational platform has been provided for the convenience of end users and stakeholders. The tool has been tested and validated on two real-life case studies pertaining to the problem of decision-making under complex situations. The results clearly explain the technology selection process and justify the simplicity of the tool in both the case studies. The proposed tool will broaden the application of scenario-based decision-making approaches in wastewater management. [ABSTRACT FROM AUTHOR]

Five multiple-attribute decision-making (MADM) methods are used to rank the four most commonly used wastewater treatment technologies in India using pre-defined set of criteria and their indicators. Results show that it is difficult to get similar ranking using different MADM methods for equal set of weights. However, for varying weights all MADM methods generated similar ranking. It is found that in wastewater treatment alternative selection problem, it is essential to define set of weights considering priorities of the decision situation. Emphasis on a rational structuring of decision-making problem is more required than searching for more sophisticated MADM methods. TOPSIS is found to be the most suitable MADM method as it considers ideal and non-ideal solutions simultaneously to select appropriate wastewater treatment alternative. [ABSTRACT FROM AUTHOR]

The application of multiple-attribute decision-making (MADM) to real life decision problems suggests that avoiding the loss of information through scenario-based approaches and including expert opinions in the decision-making process are two major challenges that require more research efforts. Recently, a wastewater treatment technology selection effort has been made with a ‘scenario-based’ method of MADM. This paper focuses on a novel approach to incorporate expert opinions into the scenario-based decision-making process, as expert opinions play a major role in the selection of treatment technologies. The sets of criteria and the indicators that are used consist of both qualitative and quantitative criteria. The group decision-making (GDM) approach that is implemented for aggregating expert opinions is based on an analytical hierarchy process (AHP), which is the most widely used MADM method. The pairwise comparison matrices (PCMs) for qualitative criteria are formed based on expert opinions, whereas, a novel approach is proposed for generating PCMs for quantitative criteria. It has been determined that the experts largely prefer natural treatment systems because they are more sustainable in any scenario. However, PCMs based on expert opinions suggest that advanced technologies such as the sequencing batch reactor (SBR) can also be appropriate for a given decision scenario. The proposed GDM approach is a rationalized process that will be more appropriate in realistic scenarios where multiple stakeholders with local and regional societal priorities are involved in the selection of treatment technology. [Copyright &y& Elsevier]

Four municipal wastewater treatment plants ( WWTPs) in India based on different technologies are compared by conducting Life Cycle Assessment ( LCA) using field data. CML 2 baseline 2000 methodology is adopted in which eight impact categories are considered. SBRs ranked highest in energy consumption and global warming potential ( GWP) but also produced the best effluent with respect to organics and nutrients. Constructed wetlands have negligible energy consumption and negative GWP because of carbon sequestration in the macrophytes. Emissions associated with electricity production required to operate the WWTPs, emissions to water from treated effluent and heavy metal emissions from waste sludge applied to land are identified as main contributors for overall environmental impacts of WWTPs. This comparison of technologies suggests that results from LCA can be used as indicators in a multicriteria decision-making framework along with other sustainability indicators. [ABSTRACT FROM AUTHOR]

Abstract: Many technological alternatives for wastewater treatment are available, ranging from advanced technologies to conventional treatment options. It is difficult to select the most appropriate technology from among a set of available alternatives to treat wastewater at a particular location. Many factors, such as capital costs, operation and maintenance costs and land requirement, are involved in the decision-making process. Sustainability criteria must also be incorporated into the decision-making process such that appropriate technologies are selected for developing economies such as that of India. A scenario-based multiple-attribute decision-making (MADM) methodology has been developed and applied to the selection of wastewater treatment alternative. The four most commonly used wastewater treatment technologies for treatment of municipal wastewater in India are ranked for various scenarios. Six scenarios are developed that capture the regional and local societal priorities of urban, suburban and rural areas and translate them into the mathematical algorithm of the MADM methodology. The articulated scenarios depict the most commonly encountered decision-making situations in addressing technology selection for wastewater treatment in India. A widely used compensatory MADM technique, TOPSIS, has been selected to rank the alternatives. Seven criteria with twelve indicators are formulated to evaluate the alternatives. Different weight matrices are used for each scenario, depending on the priorities of the scenario. This study shows that it is difficult to select the most appropriate wastewater treatment alternative under the “no scenario” condition (equal weights given to each attribute), and the decision-making methodology presented in this paper effectively identifies the most appropriate wastewater treatment alternative for each of the scenarios. [Copyright &y& Elsevier]

Abstract: A framework for technology assessment for wastewater treatment is proposed in this work. A case study of technology selection for high rise buildings in urban centres of India is used for evaluation and to test this framework. The multiple-attribute decision-making technique is used for ranking the alternatives. The three most commonly used wastewater treatment technologies viz., activated sludge process (ASP), sequencing batch reactors (SBR) and membrane bio-reactor (MBR) are evaluated. Seven criteria having indicators derived from life cycle assessment (LCA), life cycle costing (LCC) and criteria accounting for resource constraints, robustness of the system and sustainability are used for the evaluations. The technology assessment framework used in this work will help identify appropriate wastewater treatment technologies for various decision-making situations encountered while managing wastewaters. Importantly, this study validates the theory that it is the decision situation which decides the appropriateness of the technology and not the technology itself. Hence, the definition of appropriate technology given by Murphy et al. [4] is more convincing for water and sanitation technologies. [Copyright &y& Elsevier]