Aqua

Abstract: Amphiprion barberi, a new species of anemonefish fish, is described from 46 specimens, 16.3-85.8 mm SL, collected at depths of 2-10 m from coral reefs of Fiji, Tonga, and Samoa. It is closely allied to A. melanopus, which is widely distributed in the western Pacific. The two species exhibit significant colour-pattern differences, including a mainly reddish orange body in A. barberi and dark brown or blackish body in A. melanopus. Adults of the new species also possess fewer spinules (11-19 versus 19-26) in the upper- ...

ABSTRACT Computational fluid dynamics (CFD) can be applied to the advancement of dissolved air flotation (DAF) plant design. The use of CFD in design and predictive analysis, in particular here with reference to the upgrading of an existing DAF plant from 30 to 60 Ml/d and associated diagnostics, while still developing, helped by the emergence of ever more powerful computational systems, can be regarded as an established tool providing beneficial and useful data, although on occasions care may be required in the interpretation of results. The initial CFD studies were undertaken using the existing and upgraded works flows and structures at both 'low' and 'high' temperatures, i.e. 2 and 20 degrees C, while the modelling results are reported using graphical representations of 'contours of flow velocity' and 'velocity vectors'. In addition the degree of short circuiting based on T(10) together with other retention parameters T(50) and T(50)/m are reported. Further modifications were also considered: how changes to the incline baffle and tank depth can impact on the predicted distribution, vorticity and in practice on the actual subnatant water quality measured in terms of turbidity. Finally applying CFD to DAF plant design is shown to be a beneficial tool for the designer.

ABSTRACT Computational fluid dynamics (CFD) can be applied to the advancement of dissolved air flotation (DAF) plant design. The use of CFD in design and predictive analysis, in particular here with reference to the upgrading of an existing DAF plant from 30 to 60 Ml/d and associated diagnostics, while still developing, helped by the emergence of ever more powerful computational systems, can be regarded as an established tool providing beneficial and useful data, although on occasions care may be required in the interpretation of results. The initial CFD studies were undertaken using the existing and upgraded works flows and structures at both 'low' and 'high' temperatures, i.e. 2 and 20 degrees C, while the modelling results are reported using graphical representations of 'contours of flow velocity' and 'velocity vectors'. In addition the degree of short circuiting based on T(10) together with other retention parameters T(50) and T(50)/m are reported. Further modifications were also considered: how changes to the incline baffle and tank depth can impact on the predicted distribution, vorticity and in practice on the actual subnatant water quality measured in terms of turbidity. Finally applying CFD to DAF plant design is shown to be a beneficial tool for the designer.

Water utilities are an essential service that helps protect public health during crises. The Covid-19 pandemic revealed that crisis preparedness is a crucial capability that water utilities must possess. The purpose of this paper is to identify managerial actions and responses that were undertaken by water utility managers in order to reduce the risk related to the first economic lockdown caused by the unexpected Covid-19 crisis. As water utilities should learn from Covid-19 so as to strengthen their future risk preparedness, the paper offers some theoretical underpinnings on risk management. As a result of literature analysis, we focus on the risk management framework that distinguishes five types of risk. The survey was carried out among 116 waterworks in Poland in April 2020. The results indicate the importance of minimising liquidity risk and supply chain risk, which is relevant to the adopted theoretical framework. The findings also highlight the importance of a category that w...

Résumé/Abstract Haloacetic acids (HAAs) are formed during the chlorination of water containing organic matter but predictive models for their formation are not well established at present and have not been applied to UK water systems. In this paper two different ...

ABSTRACT The importance of performance assessment in the water industry is demonstrated by the increasing number of initiatives taking place around the world. Since the first initiatives, which started 15 years ago, the topic has evolved significantly although it still presents challenges to be tackled. Five years ago, a project on performance assessment of urban infrastructure services was submitted to the European Union under the COST programme. As a consequence, the COST C18 Action was created. This paper presents the main conclusions and future key research areas from the project. In the solid waste sector, existing practical experience is less advanced, but methodologies and conclusions will be equally applicable in performance assessment projects.

ABSTRACT In semi-arid regions experiencing rapid population growth, rainwater harvesting is becoming increasingly important. Roof-collected rainwater is the exclusive water source for many households worldwide. Improper collection, storage or treatment of rainwater can result in adverse health effects. This study surveys rainwater harvesting practices and examines water quality from these systems. At 36 households, stored 'pre-filtration' rainwater and 'post-filtration' water from the kitchen faucet used for drinking and cooking were sampled. Rainwater harvesters desire to conserve water and believe that rainwater is more healthful than surface or groundwater. Almost 95% of homeowners use filtration and purification devices, but 64% have never tested their water. Coliform bacteria were not found in any post-filtration water, but some pre-filtration water samples were high in total heterotrophic bacteria. Lead levels exceeded the United States Environmental Protection Agency (USEPA) standard of 15 mu g L--1 in 25% of pre-filtration samples and 6% of post-filtration samples. First-flush diversion devices significantly decreased the likelihood of pre-filtration lead levels above 15 mu g L-1. Aluminium, copper and iron exceeded USEPA recommended levels in a small percentage of homes. Although water from roof-collected rainwater harvesting systems was generally within drinking water standards, regular testing should be encouraged to avoid potential health problems.

Biofouling of polyamide membranes is one of the main barriers faced by reverse osmosis (RO) technologies to supply fresh water. Currently, biofouling is addressed by feed water pretreatment using chlorine, followed by membrane cleaning. Chlorine damages polyamide membranes and also generates harmful disinfection byproducts. Thus, safer strategies are needed to prevent biofouling in polyamide membrane systems. This review investigates the applicability of the following non-oxidizing biocides in preventing and controlling biofouling in RO systems, including their antimicrobial efficiency, hazard levels, membrane compatibility, and applicability to drinking water treatment: (1) 2,2-dibromo-3-nitrilopropionamide (DBNPA); (2) 2-methyl-4-isothiazolin-3-one (MIT); (3) sodium bisulfite (SBS), (4) phenoxyethanol (PE), (5) sodium benzoate (SB). According to this review, MIT and DBNPA present most of the features attributed to an ideal anti-biofouling chemical but also are the most hazardous b...

Résumé/Abstract The performance of a new commercial tannin-based cationic polymer (TBP) has been investigated at bench-scale in terms of its capability to coagulate colour and humic material. The TBP is characterised as a moderate-to-high molecular weight polymer ...

ABSTRACT Data is presented on chemical and physical changes observed on a series of 15 specially made writing papers as part of the development of the new ASTM standard D6789-02. Papers were exposed to north window, fluorescent, and halogen illumination ...

... B. Petrusevski (corresponding author) SM Shahidullah SK Sharma International Institute for Infrastructural, Hydraulic and Environmental Engineering (IHE), PO Box 3015 ... The filters were operated at a constant filtration rate of 0.23 m/hr thus allowing adsorption times of 21 or 33 ...