Disinfection Of Pathogens Research Articles

Decentralised Wastewater Treatment and Recycling in Urban Villages

Decentralised wastewater recycling and irrigation systems have been established with industry partners in Perth urban villages. The project is now monitoring and evaluating these systems for performance and reliability to meet regulatory standards, effects on soil and vegetation, pathogen disinfection, nutrients prevented from infiltration to groundwater or infiltrated and recycled, maintenance issues of the systems and the effective amount of scheme and bore water saved in the long term. Three trial sites were established for the Premier's Water Foundation (PWF) (Bridgewater Lifestyle Village 389 household greywater recycling; Timbers Edge Resort Village 260 houses to common greywater recycling; Banksia Tourist Village 162 park homes to common wastewater treatment) The research team continues to conduct research on other promising sites (Somerville Ecovillage with 104 houses on dry composting toilets and greywater recycling and Tuart Lakes Lifestyle Village with 415 park homes to common wastewater treatment). This paper provides an overview of the results to date from five research topics: completed are a new regulatory framework, a technical elements model, and a new water balance and efficiency rating tool. For the fourth topic, trials found that mosquito control measures are effective. Fifthly, early monitoring results for a “zero emissions nutrients” (ZEN) model for urban land developments are promising with nutrient leaching within prescribed limits.

Disinfecting and Stabilizing Biosolids Using E-Beam and Chemical Oxidants

Municipal sewage and sludges can harbor a variety of infectious microorganisms as well as estrogenic compounds and their metabolites. Biosolids and other residuals generated from municipal wastewater treatment facilities need to be used for beneficial purposes such as land application. To reduce the potential for adverse environmental and human impacts, it is critical that novel approaches be investigated so that municipal biosolids can be disinfected and stabilized to reduce the pathogen loads and levels of estrogenic compounds. The overall objective of this project was to demonstrate the disinfection and enhanced stabilization of municipal biosolids when high energy (10 MeV) Electron Beam (e-beam) technology is coupled with oxidants such as chlorine dioxide and ferrate.High energy E-Beam is effective as a disinfection technology. Significant reductions of all target organisms can be achieved in municipal biosolids depends on the dose that is employed. An e-beam treatment system utilizing 15 kGy e-beam dose has been designed and mathematically modeled and validated. Based on these engineering design considerations, e-beam treatment was shown to be cost-effective. There was synergistic disinfection of pathogens when e-beam is coupled with oxidants such as chlorine dioxide and ferrate. E-Beam at 8 kGy was unable to destroy estrogenic activity in the sludge samples. Ferrate (100 ppm) was capable of destroying estrogenic activity in the biosolid samples with or without the addition of e-beam irradiation. Chlorine dioxide (100 ppm) was not effective at destroying the estrogenic activity either by itself or in combination with e-beam. The combination of 100 ppm of ferrate with 8 kGy of e-beam promoted the stabilization of aerobic and anaerobic sludge samples as indicated by BOD, VSS and SOUR test results. The results demonstrate that 10 MeV e-beam is capable of cost-effectively inactivating a variety of bacterial and viral pathogens in aerobically and anaerobically digested biosolids. Overall, thes results suggest that when e-beam is combined with ferrate significant reductions of microbial pathogens, estrogenic compounds and biosolid stabilization can be achieved.This title belongs to WERF Research Report Series.ISBN: 9781843392996 (eBook)

Photocatalytic TiO2 thin films by aerosol-deposition: From micron-sized particles to nano-grained thin film at room temperature

A nano-sized, TiO2 photocatalytic thin film with a dispersion of anatase crystallites was successfully fabricated from a micron-sized powder by aerosol deposition (AD) at room temperature (RT). Extremely rough, network-structured, photocatalytic thin films were obtained without any binder or heat treatment. The films were photocatalytically active under both ultraviolet (UV) and solar light as a result of their nano-sized, anatase grains and amorphous phase. Various photocatalytic evaluations confirmed the excellent photocatalytic performance of the AD TiO2 film in terms of organic degradation, pathogen disinfection, and hydrophilicity. This enhanced photocatalytic performance was attributed not only to the nano-crystalline anatase grains, but also to the exceptionally rough, network microstructure and nano-projections capable of supporting the enhanced loading of organic contaminants onto the film surface. Furthermore, because the nano-grained, AD TiO2 photocatalytic thin films were fabricated from low-cost, micron-sized powder with a deposition rate as high as 3μm/min at RT, this process promises to be one of the most cost-effective methods for many practical photocatalyst applications.

Standardizing photoreactivation: Comparison of DNA photorepair rate in Escherichia coli using four different fluorescent lamps

The disinfection of pathogens in water via ultraviolet light exposure is a growing treatment technology, although the potential repair of UV damage following disinfection is a continued topic of concern in many UV disinfection applications. The conditions for investigating DNA repair of microorganisms are not standardized nor often correctly reported in the literature resulting in contradicting results regarding repair abilities of specific microorganisms. In this work a protocol was developed that enables comparison of photorepair experiments from different laboratories. Four different commonly used lamp types as well as sunlight were investigated to induce photorepair in Escherichia coli. Both time-based and photorepair fluence-based comparisons were performed. It was concluded that both intensity and lamp spectra significantly affect photorepair rate. Based on photorepair fluence calculations, there was no significant difference in photorepair rate between the different lamp types or compared to sunlight, while large differences were indicated using a time-based comparison as typically reported in the literature. Interestingly, the lethal effects of solar light on E. coli overshadowed the photorepair, and after 10 min the number of E. coli cells started to decrease. Because the disinfection efficiency of the sun affected the results, laboratory-based repair experiments may only indicate “potential” photorepair, as sunlight may be more lethal than laboratory photorepair lamps.

Report: Biomedical waste management practices at Balrampur Hospital, Lucknow, India

Biomedical waste has become a serious health hazard in many countries, including India. Careless and indiscriminate disposal of this waste by healthcare establishments and research institutions can contribute to the spread of serious diseases such as hepatitis and AIDS (HIV) among those who handle it and also among the general public. The present study pertains to the biomedical waste management practices at Balrampur Hospital, a premier healthcare establishment in Lucknow, in North India. The study shows that infectious and non-infectious wastes are dumped together within the hospital premises, resulting in a mixing of the two, which are then disposed of with municipal waste at the dumping sites in the city. All types of wastes are collected in common bins placed outside the patients wards. For disposal of this waste the hospital depends on the generosity of the Lucknow Municipal Corporation, whose employees generally collect it every 2 or 3 days. The hospital does not have any treatment facility for infectious waste. The laboratory waste materials, which are disposed of directly into the municipal sewer without proper disinfection of pathogens, ultimately reach the Gomti River. All disposable plastic items are segregated by the rag pickers from the hospital as well as municipal bins and dumps. The waste is deposited either inside the hospital grounds, or outside in the community bin for further transportation and disposal along with municipal solid waste. The open dumping of the waste makes it freely accessible to rag pickers who become exposed to serious health hazards due to injuries from sharps, needles and other types of material used when giving injections. The results of the study demonstrate the need for strict enforcement of legal provisions and a better environmental management system for the disposal of biomedical waste in the Balrampur Hospital, as well as other healthcare establishments in Lucknow.

Mixing it up: Integrated disinfection scenarios in drinking water treatment

This column discusses the quandry water utilities face when attempting to concurrently achieve higher levels of pathogen disinfection and lower levels of disinfection byproducts (DBPs). Integrated disinfection, one such strategy utilities can use to achieve this goal, is the focus of this article. Two case studies, examples of integrated disinfection, are also discussed: Evaluation of chlorine dioxide and ozone; and, evaluation of ozone and ultraviolet (UV) light.

RECYCLE SYSTEM OF RESOURCES WHICH APPLIED COW EXCRETA

Development for recycle technology of the organic refuses is a subject to prevent environmental pollution and to secure natural resources. In a case of Japan, most of natural resources are imported from foreign countries. Therefore organic refuses are increasing and accumulating in any place of Japan. This is coursedby effect of global warming. We developed a recycle system of resources that is consisted from methane fermentation and composting. This recycling system was built in Hokkaido. Hokkaido is a famous place for dairy farming and approx. one million number of milk cows is keeping. In this system, cow excreta is converted to electric energy andmanure by microorganisms.In this report, we describe (1) summary of our recycle system which was built in Bekkai-cho, (2) results of fundamental study of seed microorganisms for startup of methane fermentation, (3) operational condition of methane fermentation, (4) effect of temperature on disinfection of pathogens, and (5) importance of recycle system and subject of methane fermentation.

The effect of high-dose-rate X-rays on E. coli 0157:H7 in ground beef

The emergence of pathogens in today's world has increased the need for new, portable, nonthermal sterilization technologies. The University of Missouri, Columbia in cooperation with the Institute of Electrophysics, Ekaterinburg, Russia, have built and tested a new accelerator based on solid-state opening switches for the disinfection of pathogens in food. The accelerator utilizes a new solid-state opening switch to generate 40 ns, 2OO-keV electron beam pulses. These pulses were then converted to Bremsstrahlung X-rays using an integral X-ray converter. The efficacy of treating E. coli 0157:H7. In ground beef was tested by irradiating frozen ground beef with the high-dose-rate 10/sup 7-6/ rads/s X-ray pulses. Comparison studies were also done with a Cobalt-60 source located at the Missouri University Research Reactor. The results of the study are presented in this paper.

The Detection and Disinfection of Pathogens in Storm-Generated Flows

A recreational water's disease-producing potential is usually assessed by bacterial indicators of human fecal contamination, however many of these indicator bacteria also originate from soils, vegetation, and animal feces. Stormwater runoff can contain high densities of the nonhuman indicator bacteria and epidemiological studies of recreational waters receiving stormwater runoff have found little correlation between indicator densities and swimming related illnesses. In addition a number of non-enteric pathogens found in stormwater runoff have been linked to respiratory illnesses and skin infections, a risk which is not assessed by the present fecal indicators. Therefore, for receiving waters with predominantly stormwater discharges, the current bacterial indicators are not suited to accurately assess the water's total illness producing capacity. The intermittent and irregular nature of stormwater discharges causes unique disinfection requirements which are discussed in connection with present practices and developments. The need for epidemiological studies to assess the risk from nonhuman and non-enteric pathogens is recommended.

Detection and disinfection of pathogens in storm-generated flows.

The disease-producing potential of recreational waters is currently estimated through the use of certain bacterial indicators that are believed to be positively correlated with the presence of fecal contamination. In general, these indicators and their recommended limiting values have been adopted for use from existing standard methods for the analysis of sanitary waste water. However, no indicator currently in use today exists solely in the feces of man and not also elsewhere, e.g., in soils, vegetation, and the feces of animals. Storm-water runoff is often rich in bacteria originating from these nonhuman sources and can contain high densities of indicator bacteria; however, existing epidemiological studies of recreational waters receiving storm-water runoff have reported little correlation between current indicator densities and the incidences of swimming illnesses. In addition, microbial analyses of storm-water runoff have revealed a predominance of nonenteric disease-causing bacteria and viruses that have been linked to respiratory illnesses and skin infections. Fecal-based indicators in use today provide no information on the risks resulting from body contact with these nonenteric pathogens. Consequently, for receiving waters containing discharges that originate primarily from separate storm drainage systems, current bacterial indicators are ill suited to accurately assess the water's total illness-producing capabilities. This paper briefly reviews the development of current bacterial standards and evaluates their adoption in the field of storm-water testing. The unique disinfection requirements of storm-generated runoff are discussed, and advanced disinfection practices are reviewed. The need for additional epidemiological studies that address the disease-causing potential of nonhuman and nonenteric pathogens commonly found in storm-water runoff from urban, agricultural, and rural watershed areas is emphasized in order to determine the actual health risks associated with storm water runoff contact.