Water scarcity leads to an increased use of reclaimed water, which in turn calls for an improvement in water reclamation procedures to ensure adequate quality of the final effluent. The presence of infectious Cryptosporidium oocysts (IOO) in reclaimed water is a health hazard for users of this resource. Here, we gathered information on Cryptosporidium (concentrations, infectivity and genotype) in order to perform quantitative microbial risk assessment (QMRA). Moreover, data concerning the spores of sulphite-reducing clostridia (SRC) were used to undertake QMRA at a screening level. Our results show that the probability of infection (PI) by Cryptosporidium depends on the tertiary treatment type. The mean PI using the exponential dose-response model was 3.69 × 10−6 in tertiary effluents (TE) treated with UV light, whereas it was 3 log10 units higher, 1.89 × 10−3, in TE not treated with this disinfection method. With the β-Poisson model, the mean PI was 1.56 × 10−4 in UV-treated TE and 2 log10 units higher, 4.37 × 10−2, in TE not treated with UV. The use of SRC to perform QMRA of Cryptosporidium showed higher PI than when using directly IOO data. This observation suggests the former technique is a conservative method of QMRA.
ABSTRACT
The City of Carson City (City) Wastewater Reclamation Plant (WRP) is facing several effluent management challenges, which include increased effluent nitrogen concentrations, seepage from its reclaimed water storage reservoir, and increased influent flow due to growth. The City desires an economical solution that will allow it to continue its 100 percent reuse program as well as protect the public health and environment. The City approached the problem by working with the Nevada Department of Environmental...
Abstract:
This paper analyses informal networks and their utilisation during a period of water scarcity in an upstream and a downstream district in the Khorezm Province, Uzbekistan. The evaluation is based on an organisational theory approach on informal networks. Communication patterns between farm managers, district water departments and district governors in a year with a sufficient amount of water and in a year of water scarcity are compared with informal network structures. The analysis shows that in the...
Executive Overview
New voices are beginning to be heard in the debate over water, and new ideas – good and bad – considered. Among the most powerful and controversial of these new ideas is that water should be considered an “economic good” – subject to the rules and power of markets, multinational corporations, and international trading regimes.
In the last decade, this idea has been put into practice in dozens of ways, in hundreds of places, affecting millions of people.
Prices have been set for water...
One of the largest capacity wastewater treatment plants in Europe is under construction on a small plot of land at Ringsend, on Dublin Bay in Ireland. Sequencing batch reactor (SBR) technology and 100,000 diffusers from ITT Industries` Sanitarie unit was selected to meet the challenging waste treatment needs for this site.
When Dublin`s wastewater treatment plant was built in the 1970s, it answered the Irish capital`s population and environmental needs. But as environmental awareness and Dublin`s population has...
The Water Corporation of Western Australia has over a number of years been investigating various water treatment technologies aimed at dissolved organic carbon (DOC) removal. Research was prompted by intermittent outbreaks of DMTS (Dimethyl Trisulphide) in the clearwater distribution system. The presence of DMTS in tap water is noted as a “swampy” odour, and is suspected to be the product of biological action in the distribution system. DOC in the treated water promotes biofilm growth in the distribution system,...
1.1 Scope and Objectives
A small number of viable options are presently available for the bleaching of wood pulp (delignification and brightening) during the manufacture of pulp and paper. The use of chlorine dioxide (ClO2) in the bleaching process has largely superceded the earlier use of Cl2, or elemental chlorine, in the majority of North American pulp mills: It was discovered over a decade ago that the previous widespread use of Cl2 contributed to the production and subsequent release to the environment of...
Abstract
Africa
The economic and social needs of Africa depends more on its environmental resources but these natural resources are seriously declining and that is really effecting the entire region. Sustainable development in this rapidly changing region has become an imperative, and must take place in the complex context of a diverse and changing ecosystem, political transition and evolution toward market economies.
The region is heading towards integrating environmental components into sectors like...
Deutsche Telekom and NTT Stand Out in the First Environmental Check of the Telecommunications Industry
Deutsche Telekom AG and Nippon Telegraph & Telephone (NTT) are both first in an independent Environmental-Rating of 16 telecommunication companies from eleven countries carried out by the Munich-based rating agency ökom. Both companies received the grade C+ and therefore stood out against the industry average of D+. Telekom Italia Mobile and the Dutch Royal KPN were the tail-lights, both receiving a D-. The...
Introduction
Pollution Prevention Guidelines to provide technical advice and guidance to staff and consultants involved in pollution-related projects. The guidelines represent state-of-the-art thinking on how to reduce pollution emissions from the production process. In many cases, the guidelines provide numerical targets for reducing pollution, as well as maximum emissions levels that are normally achievable through a combination of cleaner production and end-of-pipe treatment. The guidelines are designed to...
The main advantage of ex situ treatment is that it generally requires shorter time periods, and there is more certainty about the uniformity of treatment because of the ability to monitor and continuously mix the ground water. Ex situ treatment, however, requires pumping of ground water, leading to increased costs and engineering for equipment, possible permitting, and material handling.
Physical/chemical treatment uses the physical properties of the contaminants or the contaminated medium to destroy (i.e,...
In the semi-arid region surrounding Whyalla in South Australia, BHP is creating an artificial wetland that promises to make its effluent cleaner than its input water. The wetland is projected to cost around 40% of a conventional treatment works, with significantly less operating costs. The project will conserve one of the most precious resources in the world’s driest country - water - and will improve the local environment. The wetland`s design may also be picked up by local authorities to treat stormwater and...
` In order to determine the impacts of a particular discharge on ambient water quality, it is usually necessary to model the diffusion and dispersion of the discharge in the relevant water body. The approach applies both to new discharges and to upgrading of existing sources. This note provides guidance on models that may be applicable in the context of typical Bank projects.`
Introduction
Mathematical models can be used to predict changes in ambient water quality due to changes in discharges of wastewater. In...
Introduction
Any new technology must overcome perceptions of the marketplace, which are not accurate. As a technology moves into new areas of application, new misconceptions also arise. Crossflow membrane technology is no exception.
The first man-made, pressure-driven `crossflow` membranes were made in flat sheet form. This membrane had to be configured in a device, and was first made in tile obvious `plate-and-frame` design. The spiral-wound design resulted as a response to the high cost, large size, and...
Abstract
This paper describes two successful applications of ultrafiltration (UF) and reverse osmosis (RO) membrane technology used to reclaim water, reduce waste water discharge costs. The first case history covers oily waste water treatment at a major aluminum beverage can manufacturing plant. The second case describes treatment of waste water from a multi-plating bath section of a major wheelchair manufacturing facility. The mechanisms of separation effected by both UF and RO are described at the molecular...
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