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The design of electrodes is crucial to electrocoagulation process (EC), specifically, with respect to pollutant removal and energy consumption. During EC, the mechanisms for interaction between different electrode arrangement and electrode reactions remain unclear. This work presents an integrated EC process based on horizontal bipolar electrodes (BPEs). In the electrochemical cell, the graphite plates are used as driving cathode while either Fe or Al plates serves as driving anode and BPEs. The BPEs are placed horizontally between the driving electrodes. For municipal wastewater treatment, the pollutant removal efficiency and energy consumption in different configurations of two-dimension electrocoagulation (2D-EC) system with horizontal BPEs were investigated. The removal efficiency of turbidity, total phosphorus and total organic carbon increased significantly with the number of BPEs. Noted that the energy consumption for TP removal decreased by 75.2% with Fe driving anode and 81.5% with Al driving anode than those of 2D-EC, respectively. In addition, the physical field simulation suggested the distributions of potential and current in electrolyte and that of induced charge density on BPE surface. This work provides a visual theoretical guidance to predict the distribution of reactions on BPEs for enhanced pollutant removal and energy saving based on electrocoagulation process for municipal wastewater treatment. [ABSTRACT FROM AUTHOR]

This paper assesses the significance of stakeholder discourses on uses of water by aquaculture for public policy. Our discourse analysis focuses on the experiences with inland aquaculture in Thailand, drawing from interviews with stakeholders, and evidence in public documents such as newspapers and television news reports. A key finding is that fish farms suffer significant losses from polluted run-off entering water bodies where fish are grown. Mass mortality events in river cage culture, in particular, attract media attention and are the core of the aquaculture-as-victim discourse. Fish farms are also adversely impacted by river management and current water allocation policies. Inland shrimp farming has received more negative media and scientific attention than fish farming, and is the focus of the aquaculture-as-villain discourse. A third, aquaculture-as-benign discourse, is used widely to describe fish pond culture, and more rarely to promote aquaculture in low-quality water bodies or as part of integrated nutrient and waste re-use farming systems. The findings strongly imply that aquaculture farmers should be included as a stakeholder in the management of watersheds and rivers, as well as the negotiation and allocation of water resources. They also suggest a need for aquaculture development policies to pay closer attention to water quality and allocation issues. [ABSTRACT FROM AUTHOR]

We investigated the impacts of on-site sanitation systems to local groundwater. In this year-long study, we monitored the response of faecal contamination levels to hydroclimatological factors including rainfall and groundwater table. Concentration of faecal indicators—E. coli (ESC), Enterococcus (ENT), nitrate—in thirteen pairs of shallow and deep wells were determined every 7-14 days. All samples from shallow wells were tested positive for faecal contamination (ESC and ENT > 1 MPN/100 mL) but concentration varies. A maximum of 24,000 MPN/100 mL were recorded in some shallow wells. Water from deep wells showed lower susceptibility to contamination with only 4 and 23% of samples tested positive for ESC and ENT, respectively. Concentrations of ESC and ENT were lower too, with a maximum of 5 MPN/100 mL and 28 MPN/100 mL, respectively. Fluctuation in contamination among the wells was described by four archetypal responses to hydroclimatological forcing: (i) flushing during the onset of wet season, (ii) dilution over the course of the wet season, (iii) concentration during the dry season, and (iv) synoptic response to storms. Previous studies attempting to link the prevalence of faecal/waterborne diseases and temporal factors (e.g., dry vs wet season) have produced differing outcomes. Our study may help explain the relevant hydrological mechanisms leading to these varying observations. Presently, most communities in Thailand have access to ‘improved’ sanitation systems. However, due to the unsustainable implementation of these systems, the otherwise viable drinking-water resources in the form of the abundant local groundwater has become a genuine health hazard. [ABSTRACT FROM AUTHOR]