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Disinfection with chlorine is a common practice to ensure secured drinking water, but results in potentially harmful disinfection by-products (DBPs), when excess chlorination is done. The US Environmental Protection Agency (US EPA) has established Stage 1 and Stage 2 disinfection by-product Rules (DBP rules) to control DBP exposure. A modified version of the Canadian Council of Ministries of the Environment water quality index (CCME WQI) is used to assess water quality. CCME WQI is a globally accepted index to assess water quality, but is too generic to be used for DBP rules. The study developed a scheme to make the index suitable for DBP rules. A scoring method based on an analytic hierarchy process (AHP) is applied to assign weights based on DBP rules. A previously modified CCME WQI (Islam et al., 2014) is adapted along with the weights to perform the assessment at the distribution network (DN). A case study was performed on 7 sampling stations in a Québec City DN. The spatial water quality variations are presented using kriging - a geostatistical method, which identifies the regions with relatively poor water quality and highlights the potential locations for re-chlorination points. The proposed assessment formulation is flexible to handle situations with limited data, which makes it especially suited to smaller municipalities. [ABSTRACT FROM AUTHOR]

Arab countries are primarily situated in arid environments and face serious water scarcity challenges due to growing populations, urbanization, and climate change impacts. Reusing greywater, if adequately treated at the point of generation, poses less human health risk as compared to blackwater reuse. Consumers have several reasons for being unwilling to reuse greywater, including potential health risk, religious and cultural concerns, and feeling uncomfortable. There are several possible reuse applications of treated greywater, such as watering plants, floor cleaning, landscaping, toilet flushing, etc. Therefore, it is important to assess consumer perceptions about greywater reuse before its implementation in any region. In this research, a framework based on greywater reuse indicators (GWRI) was developed to assess consumer perceptions before and after introducing low-cost treatment (LCT). Later the framework was implemented for Muscat, Oman. A questionnaire survey was carried out with 110 households located in diverse socioeconomic settings to collect data about general demographics, existing water uses, water sources, greywater applications (after LCT), and in-house plumbing systems. Seven key GWRI were estimated and aggregated to develop an overall consumer perception index (CPI). The study results revealed that CPI improved significantly from 'very low' to 'high' after introducing LCT. However, governments should provide financial assistance to consumers for improving in-house plumbing systems, based on detailed investigations. The study revealed that the CPI can be applied across the globe and can save time and effort for municipal managers, engineers, and policy makers by providing information that will enable effective decision-making. [ABSTRACT FROM AUTHOR]

To maintain desirable residual chlorine for a groundwater source, optimizing the chlorine dose in small- to medium-sized water distribution systems (SM-WDS) is a daunting task in developing countries. Mostly, operators add a random chlorine dose without recognizing the smaller size of their distribution network. In this research, a modelling framework for optimizing chlorine dose in SM-WDS is developed. In order to evaluate its practicality, the proposed framework has been applied in a case study of a residential neighbourhood in Lahore (Pakistan) with a small network spanning over 0.35 km2. Three datasets for residual chlorine were monitored at 6 locations spread over the study area. EPANET 2.0 software was used for hydraulic and residual chorine modelling. The bulk decay coefficient (Kb) was determined in the laboratory, whereas the wall decay coefficient (Kw) was estimated by calibrating the simulation results with the residual chlorine determined in the field. Based on the calibrated EPANET simulations, a fuzzy rule-based model was developed for pragmatic application of the proposed framework. Scenario analyses for different situations have also been carried out for achieving residual chlorine required at the consumer end. This exercise revealed that much lower chlorine doses than the existing practice can generate detectable chlorine residuals. Moreover, the model can be used to deal with emergency situations, which may arise in developing countries due to viral outbreaks and cross-contamination events in SM-WDS. [ABSTRACT FROM AUTHOR]