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The disinfecting ability of hibiscus seed proteins against Escherichia coli, total coliforms and faecal coliforms in water treatment was investigated. Hibiscus seeds are widely available as a primary source of protein in tropical countries. Using varying doses of extracts, partial inactivation of faecal coliforms and E. coli was achieved. Hibiscus sabdariffa crude extract (SCE) achieved 67% faecal coliform inactivation whereas Hibiscus cannabinus (kenaf) crude extract (KCE) achieved 57% using dosages of 200 mg/l. Additionally, E. coli were observed to be more sensitive to KCE than SCE, with maximum inactivations of 65% and 60%, respectively. Furthermore, complete bacterial regrowth was witnessed with the extracts after 72 h storage time. However, purified sabdariffa protein (PSP) and purified kenaf protein (PKP) showed complete (100%) bacterial inactivation post-treatment, using a dose of 1·48 mg/l. Additionally, PSP and PKP achieved 92% and 90% turbidity removal, respectively, from a value of 11·9 NTU. Therefore, the use of PSP and PKP in water treatment could improve access to clean water in developing countries. [ABSTRACT FROM AUTHOR]

To date, the and stable isotopic composition of freshwaters has received little attention compared to stable isotopes in precipitation. Specifically, studies characterising the stable isotopic variability of surface waters on regional and local scales are limited. Here, the and stable isotopic compositions of raw and partially treated waters from 16 UK water treatment works are examined. The water treatment works abstract surface waters from a range of catchments (upland versus lowland and semi-natural versus anthropogenically impacted). The investigation of stable isotope composition and deuterium excess (-excess) revealed a high degree of spatial and temporal variability. Compared to rainfall, the spatial and temporal variability of surface water is more complex and catchment-dependent. Multiple linear regression analysis identified moderately strong relationships between catchment controls (altitude, mean rainfall, base flow index, aquifer permeability, location) and , and -excess of raw and partially treated waters Results suggest that catchment controls explain 60% ( ), 66% ( ) and 74% (-excess) of the variation in isotopic composition of raw water. Results also indicate that catchment permeability has a stronger influence on surface waters isotopic composition than altitude, latitude or rainfall effects. The potential benefits from the use of isotopic composition data in the water supply are discussed. [ABSTRACT FROM AUTHOR]

This paper examines the velocity field in an idealised heterogeneous open channel during normal flow conditions, corresponding to two different subcritical flow conditions (discharges of 0·040 m/s and 0·056 m/s, with corresponding Froude numbers 0·51 and 0·57). The bed of the channel is formed of two full-length, longitudinal strips of equal width, a smooth section constructed from polyvinyl chloride and a rough section constructed from gravel ( = 10 mm). The results indicate that the turbulence appears to propagate vertically from the rough bed and horizontally over the rough-smooth boundary. There is also evidence to suggest that the turbulent momentum transfer is maximised at the rough-smooth boundary. Secondary flow structures are seen to exist due to the rough-smooth boundary and provide another mechanism for momentum transfer. These transfer mechanisms are important in understanding the effect of a heterogeneous channel bed on open-channel flow. [ABSTRACT FROM AUTHOR]

The formation of potentially harmful trihalomethanes (THM) when using chlorine as a disinfectant in potable water supplies has led to tighter regulatory controls and hence a need for better models for THM management. The prediction of THM concentration is difficult due to the complex and changing hydrodynamic and chemical regimes found in water treatment works and distribution systems. A simple and cost-effective model is described to model chlorine decay and total THM concentration through water treatment works and within distribution systems. With knowledge of the bulk chlorine decay characteristics and the THM productivity of the water, this model offers a simple and straightforward tool which can be readily applied to water treatment works and distribution systems alike to provide an initial assessment of the risks of total THM formation at different sites, and to identify sites and systems at risk of compliance failure. [ABSTRACT FROM AUTHOR]

The article discusses papers within the March 2012 issue of "Proceedings of ICE: Water Management," including a paper that offers a new approach to describe the surface profile of a hydraulic jump formed in an open channel of arbitrary cross-section.

An introduction is presented in which the editor discusses various reports within the issue on topics including the simulation of disinfection by-product modelling in water treatment works, decision-support system targeted at effective water resource management, and open channel flow.

The author reflects on the role of aid organizations and water engineers in addressing the devastations created by the natural disasters in Burma and China. He states that immediate assistance is needed to acquire a rich supply of safe drinking water and suitable sanitation measures so that the afflicted will not suffer to diseases associated with water impurities. He emphasizes that the knowledge needed by water professionals in alleviating the situations is rooted on fundamental research.