The formation of disinfection by-products from the chlorination and chloramination of amides

This study examined the potential of six aliphatic and aromatic amides, commonly found in natural waters or used as chemical aids in water treatment, to act as organic precursors for nine haloacetamides (HAcAms), five haloacetonitriles (HANs), regulated trihalomethanes (THMs) and haloacetic acids (HAAs) upon chlorination and chloramination. The impact of key experimental conditions, representative of drinking water, including pH (7 & 8), retention time (4 & 24 h) and bromide levels (0 & 100 μg/L), on the generation of the target DBPs was investigated. The highest aggregate DBP yields upon chlor(am)ination were reported for the aromatic and hydrophobic hydroxybenzamide; 2.7% ± 0.1% M/M (chlorination) and 1.7% M/M (chloramination). Increased reactivity was observed in aliphatic and hydrophilic compounds, acrylamide (2.5 ± 0.2% M/M) and acetamide (1.3 ± 0.2% M/M), in chlorination and chloramination, respectively. The addition of bromide increased average DBP yields by 50–70%. Relative to chlorination, the application of chloramines reduced DBP formation by 66.5% (without Br−) and by 46.4% (with Br−). However, bromine incorporation in HAAs and HAcAms was enhanced following chloramination, of concern due to the higher toxicological potency of brominated compounds

Simultaneous prediction of trihalomethanes, haloacetic acids, haloacetonitriles and haloacetamides using simulated distribution system tests

Supplementary information: https://www.rsc.org/suppdata/d1/ew/d1ew00824b/d1ew00824b1.pdf (359KB PDF)Anglian Water; AW Innovation, UK.https://www.rsc.org/suppdata/d1/ew/d1ew00824b/d1ew00824b1.pd

Simultaneous prediction of trihalomethanes, haloacetic acids, haloacetonitriles and haloacetamides using simulated distribution system tests

This study analysed the spatial and temporal occurrence of 29 disinfection by-products (DBPs) formed by chlorination and chloramination. Four full-scale treatment works, and distribution system locations were sampled, and the results were compared with laboratory-based simulated distribution system (SDS) tests. The DBPs monitored incorporated 4 trihalomethanes (THMs), 9 haloacetic acids (HAAs), 7 haloacetonitriles (HANs) and 9 haloacetamides (HAcAms). For the first time, SDS tests were shown to successfully simulate the levels and speciation of HANs and HAcAms in both chlorinated and chloraminated systems. While THM and HAA concentrations generally increased with water age, HAN and HAcAm concentrations fluctuated and resulted in less pronounced overall increases. To explore the impact of switching the disinfectant in distribution, free chlorine and chloramines were applied in the SDS tests, which showed that chloramination not only reduces the yields of THMs (by 34%) and HAAs (by 49%), but also HANs (by 61%) and HAcAms (by 51%), although it shifts speciation towards more brominated HAAs, HANs and HAcAms species when compared against chlorination. Overall, the aim of the study was to demonstrate that SDS tests can be recommended for the simultaneous estimation of THM, HAA, HAN and HAcAm concentrations in distribution systems and to assess the effect of potential DBP minimisation strategies, such as switching the disinfectant in distribution

A novel theatre-based behaviour change approach for influencing community uptake of schistosomiasis control measures

Background: Appropriate behaviour change with regard to safe water contact practices will facilitate the elimination of schistosomiasis as a public health concern. Various approaches to effecting this change have been trialled in the field but with limited sustainable outcomes. Our case study assessed the effectiveness of a novel theatre-based behaviour change technique (BCT), in combination with cohort awareness raising and capacity training intervention workshops. Methodology: Our study was carried out in Mwanza, Tanzania and Kemise, Ethiopia. We adapted the Risk, Attitude, Norms, Ability, and Self-regulation (RANAS) framework and four phases using a mixed methods approach. Participatory project phase engagement an11 qualitative formative data were used to guide the design of an acceptable, holistic intervention. Initial baseline (BL) data was collected using quantitative questionnaire surveys with 804 participants in Tanzania and 617 in Ethiopia, followed by the theatre-based BCT and capacity training intervention workshops. Post-intervention (PI) survey was carried out after six months, with a participant return rate of 65% in Tanzania and 60% in Ethiopia. Results: The intervention achieved a significant improvement in the knowledge of schistosomiasis transmission being associated with poorly managed sanitation and risky water contact. Participants in Tanzania increased their uptake of preventive chemotherapy (Male: BL:56%; PI:73%, Female: BL:43%; PI:50%). There was a significant increase in the selection of sanitation (Tanzania: BL:13%; PI:21%, Ethiopia: BL:63%; PI:90%), safe water and avoiding/minimising contact with infested waters as prevention methods in Tanzania and Ethiopia. Some of the participants in Tanzania followed on from the study by building their own latrines. Conclusions: This study showed substantial positive behaviour changes in schistosomiasis control can be achieved using theatre-based BCT intervention and disease awareness training. With appropriate sensitisation, education and stakeholder engagement approaches, community members were more open to minimising risk-associated contact with contaminated water sources and were mobilised to implement preventive measures