Access to drinking water: time matters.

Despite the reported achievement of the Millennium Development Goals (MDGs) with respect to drinking water, lack of access to water remains widespread worldwide. The indicator used there to measure access to water in the MDGs refers to the use of an improved water source. However, the amount of time spent in collecting water is high in countries where access to drinking water supplies located on premises is not common. 26.3% of the world's population did not have such access in 2015. Thus the need to travel to a water point, possibly queue, fill water containers, and carry them home is prevalent. The amount of time and effort used in water collection can be considerable, and household surveys increasingly provide data on collection time. This study aims to demonstrate the effect of adding a 30-minute collection time component to monitor access to drinking water. This study draws on household surveys from 17 countries to highlight the widespread burden of fetching water and its significant impact on estimates of coverage. The proportion of the population with access decreased by 13% on average for these 17 countries when collection time was added as a consideration.

Laboratory evaluation of a new coagulant/disinfectant point-of-use water treatment product for emergencies.

AIMS: There is emerging evidence that point-of-use (POU) water treatment can be effective in the improvement of microbial water quality and the decrease in diarrhoeal disease incidence in humanitarian emergencies. Coagulant/disinfection products (CDPs) have the distinct advantage of providing microbial quality improvement, turbidity reductions and a free chlorine residual (FCR). The laboratory treatment performance of a novel CDP, the 'Pureit(®) ' sachet, has been evaluated under different water quality conditions. METHODS AND RESULTS: The CDP performance was evaluated with regard to bacteriological humanitarian water quality objectives as well as the recent World Health Organization recommendations for evaluating POU water treatment options. At least 4 log10 reductions of tested bacterial indicators for a 'highly protective' status were attained in the tested conditions. Treated waters were consistently below 10 MPN per 100 ml with regard to final Escherichia coli concentrations (i.e. 'low risk') with majority of samples with no detectable E. coli (i.e. 'very low risk'). Attainment of the target FCR levels (at least 0·5 and 0·2 mg l(-1) after 0·5 and 24 h respectively) was dependant on the test water matrix. FCRs are thought to have been affected by the product's formulation, which contains a quenching agent intended to reduce chlorinous tastes. Treated water turbidity levels were marginally above the nonhealth-based target of five nephelometric turbidity units, partially due to the filtration cloth employed. CONCLUSIONS: This study has served to identify the performance envelopes of the CDP under challenging conditions. In particular, initial alkaline pHs negatively affected this product's performance with regard to bacterial log10 reductions. SIGNIFICANCE AND IMPACT OF THE STUDY: This CDP has the potential to attain humanitarian drinking water quality objectives when not operating under extreme conditions; consistently achieving E. coli log10 reductions between 4·5 and 5·2 resulting in treated water with E. coli concentrations mostly below the <1 MPN per 100 ml target level.

Treatment of heavy metals by iron oxide coated and natural gravel media in Sustainable urban Drainage Systems.

Sustainable urban Drainage Systems (SuDS) filter drains are simple, low-cost systems utilized as a first defence to treat road runoff by employing biogeochemical processes to reduce pollutants. However, the mechanisms involved in pollution attenuation are poorly understood. This work aims to develop a better understanding of these mechanisms to facilitate improved SuDS design. Since heavy metals are a large fraction of pollution in road runoff, this study aimed to enhance heavy metal removal of filter drain gravel with an iron oxide mineral amendment to increase surface area for heavy metal scavenging. Experiments showed that amendment-coated and uncoated (control) gravel removed similar quantities of heavy metals. Moreover, when normalized to surface area, iron oxide coated gravels (IOCGs) showed poorer metal removal capacities than uncoated gravel. Inspection of the uncoated microgabbro gravel indicated that clay particulates on the surface (a natural product of weathering of this material) augmented heavy metal removal, generating metal sequestration capacities that were competitive compared with IOCGs. Furthermore, when the weathered surface was scrubbed and removed, metal removal capacities were reduced by 20%. When compared with other lithologies, adsorption of heavy metals by microgabbro was 10-70% higher, indicating that both the lithology of the gravel, and the presence of a weathered surface, considerably influence its ability to immobilize heavy metals. These results contradict previous assumptions which suggest that gravel lithology is not a significant factor in SuDS design. Based upon these results, weathered microgabbro is suggested to be an ideal lithology for use in SuDS.

Particle separation options for emergency water treatment.

Emergencies can result from the effects of unpredictable natural forces or from the cruelty of conflicts. The affected population is often left vulnerable to increased health risks. The victims' exposure to these risks can be reduced by timely public health interventions. Often, one of the first basic mitigations is the provision of water for essential needs. The quickest option, and generally more polluted, is of surface waters. We have reviewed particle separation options for emergency water treatment of surface waters. These vary from granular filtration package treatment facilities to ceramic candle filters and have therefore been broadly classified in three categories: modular, mobile and point-of-use (or household). The operational requirements and process limitations that can influence the choice of each option are discussed alongside with their underlying particle separation mechanisms and performance data.