Article

Assessing Potential Health Risks from Viruses and Parasites in Reclaimed Water in Arizona and Florida, USA

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Wastewater reuse has been mandated in both the states of Arizona and Florida, U.S.A. In Arizona, standards have been set for enteric virus and Giardia levels to maintain a specified effluent quality depending on the reuse, while in Florida, specified treatment control has been implemented. Data on virus levels in treated wastewaters have been generated in both states. Average virus levels ranged from 13-130 pfu/100L after secondary treatment while with the addition of filtration, levels were reduced to averages between 0.13 to 1.25 pfu/100L. Giardia cyst levels also dropped by 100 fold after filtration averaging 0.32/40L. Using a probability of infection model, risk of infection from 100 ml accidental ingestion ranged from approximately 2 x 10-3 to 2 x 10-4 for the levels of viruses and protozoa found in chlorinated secondary effluent and the risk was reduced to 2 x 10-4 to 2 x 10-6 with filtration and disinfection following activated sludge.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... In contrast, the QMRA approach is used to model risk profiles for specific scenarios following four distinct steps 1) hazard identification, 2) exposure assessment, 3) dose-response modeling, and 4) risk characterization (Rose and Gerba, 1991). Human health risks posed by microorganisms in wastewater have been estimated by QMRAs since the 1980s (Haas et al., 2014). ...
... Viral pathogens survive relatively long periods in water, are resistant to some treatment processes Rose and Gerba, 1991), and cause a large number of illnesses annually (Pearce-Walker et al., 2020). A recent survey found that viruses accounted for 68% of foodborne outbreaks in the U.S. between 2009 and 2013 (Brown et al., 2017). ...
Article
The burden of disease caused by the contamination of ready-to-eat produce with common waterborne microbial pathogens suggests that irrigation supplies should be closely monitored and regulated. Simultaneously freshwater resources have become increasingly scarce worldwide while global demand continues to grow. Since the turn of the 20th century with the advent of modern wastewater treatment plants, the reuse of treated wastewater is considered a safe and viable water source for irrigation of ready-to-eat vegetables. However strict, and often costly, treatment regimens mean that only a fraction of the world's wastewater supplies are being put to reuse. The purpose of this review is to explore the available literature on the risks associated with reuse water for ready-to-eat produce production including different approaches to reducing those risks as the demand for reuse water increases. It is not the intent of the authors to determine which methods of treatment should be applied, which pathogens should be considered of greatest concern, or which regulations should be applied. Rather, it is meant to be a discussion of the evolving guidelines governing irrigation with reuse water, potential risks from known pathogens common to produce production and recommendations for improving the adoption of water reuse moving forward. To date, there is little evidence to suggest that adequately treated reuse water poses more risk for produce-related illness or outbreaks than other sources of irrigation water. However, multiple epidemiological and quantitative risk assessment models suggest that guidelines for the use of reuse water should be regionally specific and based on local growing practices, available technologies for wastewater treatment, and overall population health. Though research suggests water reuse is generally safe, the assumptions of risk are both personal and of public interest, they should be considered carefully before water reuse is either allowed or disallowed in produce production environments.
... Contamination of drinking water and the subsequent outbreak of waterborne diseases are the leading cause of death in many developing nations. Therefore, virus removal during water treatment has received more attention due to the epidemiological significance of these pathogens [1][2][3]. Traditional water/wastewater treatment technologies remain ineffective for providing adequate safe water due to the increasing demand for water coupled with stringent health guidelines and emerging contaminants. In order to ensure safe drinking water for all, some membranes such as reverse osmosis forward osmosis, membrane distillation, and capacitive deionization could be promising in the desalination of both sea and brackish water. ...
... Pure PSF and modified composite PSF-Nano Ag/ZnO membranes were prepared with the phaseinversion method, which was used for preparing another type of membranes in the literature [1,2]. Casting solutions were prepared by dissolving of Polysulfone (PSF) in the solvent NMP at a water bath at (75-80)ºC with a continuous stirring rate of 500 rpm. ...
Article
Full-text available
In this work, innovative composite flat sheet polymeric membrane, made of polysulfide (PSF) combined with nanoparticles (AgNp) and nano zinc oxide (ZnONp), which have been prepared for wastewater treatment using phase inversion. The structural properties for PSF/ZnO/Ag composite UF membrane were then characterized using scanning electron microscopy (SEM), EDX analysis, and surface roughness measurement using atomic force microscopy (AFM). The mean roughness and the root mean square of this membrane are much less valuable than the polysulfide membrane without nonmaterials. On the other hand, it has been found that the pure water flux was increased from a low of 250 L/m 2 h for the pristine membrane to a high of 410 L/m 2 h for the composite membrane and the rejection rate using water containing sodium chloride was increased from 50% to 70% for the polysulfide membrane with nonmaterial's than the polysulfide membrane without nonmaterial's using the same saline solution. In addition, the membrane efficiency was studied as an antifouling due to bacterial contamination using pure bacterial colonies of Staphylococcus Aureus, and Escherichia coli. Practical experiments have shown that this combination of Zinc oxide and silver nanoparticles combined with polysulfide can be the best choice for having double characteristics of anti-bacterial and bacteriological pollution to improve membrane for wastewater treatment.
... 3. Ingestion of laboratory grown organisms may not replicate ingestion of organisms in environmental samples. Rose and Gerba (1991) and Shuval et al. (1986) summarised infectious doses for different organisms and these are shown in Table 4. In interpreting this data the above limitations need to be kept in mind. ...
... Two assumptions were made. Firstly it was assumed that 1.98x10-2 0.5 100-1000 10 4 -10 6 Ascaris lumbricoides 1-10 10-100 Ancylostoma duodenale 1-10 10-100 Trichuris trichiura 1-10 10-100 * from Rose and Gerba (1991) t from Shuval et a/. (1986) pathogen densities in Australian sludges are similar to those from other countries. ...
... However, epidemiological methods cannot be used to determine the significance of exposure to low levels of pathogens over time Gerba and Rose, 1993). Risk assessment has been used to evaluate risk associated from exposure to pathogens present in water (Rose et ai., 1991;Rose and Gerba, 1991). This methodology helps in determining the quantification of risk and costlbenefit of control strategies (Gerba and Rose, 1993). ...
... The presence of pathogenic viruses in water represents a public health hazard (Gerba and Rose, 1991). Over 120 potentially pathogenic viruses may be excreted by man, finding their way into sewage . ...
... Humans excrete are said to contain more than 100 different types of enteric viruses capable of producing infection or disease to humans (Rose and Gerba, 1991;Absar, 2005). The presence and subsequent consumption of toxic algae or organisms that feed on them also lead to serious harm to humans and other terrestrial animals. ...
Chapter
Life Cycle Assessment (LCA) is a widely used tool for estimation of environmental footprint of any products, technologies and services, throughout its whole lifecycle from cradle to grave. It is a standardized decision support system, for quantifying the different environmental impact categories and deciding upon the sustainability of each system employed. The use of LCA tools for wastewater treatment and their impact assessment is started very recently. In wastewater treatment the LCA tools compile and evaluate the inputs and the outputs, and consider their potential environmental impacts associated with the operation of the system for all types of wastewater treatment plants either for conventional or algal ponds, throughout its whole process chain. The LCA studies generally follow ISO standards (International Organization for Standardization) with baseline framework consisting of four phases’ viz. goal and scope determination, life cycle inventory analysis (LCI), life cycle impact assessment (LCIA) and interpretation of results. The inventory analysis accumulate the data or the database for analysis, using specific criteria or data quality matrices and the impact assessment is carried out with the help of different type of softwares viz. SimaPro®, Gabi®, OpenLCA®, Umberto® etc. The impact assessment transforms the mathematical data to environmental effect equivalent via the factor multiplication. The LCA studies has validated that the wastewater treatment with microalgae comparing to the conventional, can significantly reduced the negative environmental impacts, as well as the system has the advantage on low cost of operation, the possibility of recycling the nutrients in wastewater to high value products, reducing the emissions by absorption of CO2 present in the flue gases and the discharge of oxygenated effluent into the water body.
... The pathogens of main concern in the Al-Zarqa River, one of the major water resources in Jordan, include bacteria, protozoa and viruses. The last type of microorganisms are of main concern as they generally pose a greater challenge than bacteria and protozoa in food and wastewater treatment and the risk of infection can be 10-1,000 times higher than for bacteria at a similar level of exposure (Rose & Gerba 1991). Also, viruses can survive in water longer than bacteria and can tolerate changes in temperature and pH (Maunula et al. 2005). ...
Article
Full-text available
Al-Zarqa River is the second main tributary to River Jordan after the Yarmouk River. The river flow has been modified by discharge of industrial wastewater and treated domestic water. Concerns about the occurrence of waterborne pathogenic viruses in the surface waters of Al-Zarqa River prompted the analysis of the surface water quality with respect to the presence of enteric viruses. Viruses were concentrated from a total of 33 different water environmental samples including raw sewage, effluent samples and river water collected from and around the river over a period of 11 months. Calculated recovery yields for these concentration methods ranged between 2 and 8%. Polymerase chain reaction (PCR), reverse transcriptase-PCR (RT-PCR), nested RT-PCR and southern blotting hybridization analysis were used for the detection of hepatitis A virus, norovirus, astrovirus and human adenovirus 40/41, with the later one being detected in 21 (64%) of the samples that also showed previous positive presence for enteroviruses. To our knowledge, this is the first molecular biology report in Jordan describing the circulation of adenoviruses, which were detected more frequently than enteroviruses in sewage and water samples, and therefore, they can be used as an index for the presence of human pathogenic viruses in water environment. HIGHLIGHTS Occurrence of waterborne pathogenic viruses in water resources.; Circulation of adenoviruses from and around Al-Zarqa River, Jordan.; Implementation of techniques for concentrating viruses from surface and treated water, and raw sewage.; Genomic content of enteric viruses was detected by molecular techniques.; Adenoviruses can be used as an index for the presence of human pathogenic viruses in water environment.;
... If the treated wastewater will be reclaimed, virus removal is required and regulated to a performance target [58,59]. In the United States, for both indirect potable reuse (IPR) and direct potable reuse (DPR), an LRV of 12 and 8 are required when using untreated wastewater and wastewater treatment plant effluent, respectively, as a source [46,60]. ...
Article
Full-text available
The water sector needs to address viral-related public health issues, because water is a virus carrier, which not only spreads viruses (e.g., via drinking water), but also provides information about the circulation of viruses in the community (e.g., via sewage). It has been widely reported that waterborne viral pathogens are abundant, diverse, complex, and threatening the public health in both developed and developing countries. Meanwhile, there is great potential for viral monitoring that can indicate biosafety, treatment performance and community health. New developments in technology have been rising to meet the emerging challenges over the past decades. Under the current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the world’s attention is directed to the urgent need to tackle the most challenging public health issues related to waterborne viruses. Based on critical analysis of the water viral knowledge progresses and gaps, this article offers a roadmap for managing COVID-19 and other viruses in the water environments for ensuring public health.
... These enteric viruses multiply in the intestinal tract and are released in the faecal matter of infected persons. From the standpoint of health, the most important human enteric viruses are the enteroviruses, Norwalk viruses, rotaviruses, reoviruses, caliciviruses, adenoviruses and hepatitis A virus (Rose & Gerba, 1991;Absar, 2005). ...
Article
Full-text available
Wastewater effluents from industries particularly in developing countries like Nigeria are in most cases discharged into the adjoining environment; water bodies being mostly affected. Some of these wastewater effluents are untreated or inadequately treated before being discharged, which has become a worrisome phenomenon due to its impact on environmental health and safety. This paper is aimed at reviewing the environmental and health impacts of untreated or inadequately treated industrial wastewater effluents. The quality of wastewater effluents is responsible for the degradation of the receiving water bodies. This is because untreated or inadequately treated wastewater effluents may lead to eutrophication of the receiving water bodies and also create environmental conditions that favor proliferation of water-borne pathogens or toxin-producing cyanobacteria. In extension, recreational water users coming into contact with the infected water are at risk. Although various microorganisms play many beneficial roles in wastewater systems, a great number of them are considered to be critical factors in contributing to numerous water-borne diseases outbreak. Also, wastewater effluents have been shown to contain a variety of anthropogenic compounds, many of which have endocrine-disrupting properties. Since large amounts of wastewater effluents are passed through sewage treatment systems on a daily basis, there is a need to remedy and diminish the overall impacts of these effluents in receiving water bodies. In order to comply with wastewater legislations and guidelines, there is a need for adequate treatment before discharge. This can be achieved through the application of appropriate treatment processes, which will help to minimize the risks to public health and the environment. To achieve reduced discharge of wastewater into receiving water bodies, careful planning, adequate and suitable treatment, regular monitoring and appropriate legislations are necessary.
... Enteroviral infection can lead to a broad spectrum of manifestations, ranging from asymptomatic infection to serious disease and fatality (29,30). The presence of enteroviruses in the environment is a public health hazard (33) even when very few viral particles are present (36). ...
Article
Several systems for virus recovery from environmental samples and extraction of nucleic acid were tested by adding adenovirus 2 and poliovirus 1 to different sewage samples. The most promising method involved: concentration of viruses by centrifugation, and elution of the pelleted viruses by treatment with 0.25 N glycine buffer pH 9.5. The nucleic acids were extracted by adsorption of RNA and DNA to silica particles. One aliquot was directly used for a two-step PCR in a nested fashion, with specific primers for all adenoviruses; the other aliquot was used to synthesize cDNA and a nested two-step PCR with specific primers for enteroviruses. The specificity and sensitivity of the selected primers were evaluated, the 47 human adenovirus serotypes were identified and 24 different enterovirus strains were recognized. The sensitivity of the nucleic acid extraction, cDNA synthesis and nested PCR amplification was estimated to be between 1 and 10 viral particles. Sewage and polluted river samples were analyzed showing, as expected, a much higher number of positive samples by the method described than by tissue culture analysis, a high prevalence of hepatitis A virus in sewage and the adenoviruses as the most commonly detected virus in the environmental samples analyzed.
... The hypothesis of an independent action of single organisms forms the base for the (3PM. The 3PM was first used for drinking water and food technology and is an appropriate model to assess virus ingestion and the probability of infection (Rose and Gerba 1991;Rose et al. 1996;McNab 1997;Tanaka et al. 1998). ...
... Enteroviral infection can lead to a broad spectrum of manifestations, ranging from asymptomatic infection to serious disease and fatality (29,30). The presence of enteroviruses in the environment is a public health hazard (33) even when very few viral particles are present (36). ...
Article
A method for the detection of adenovirus in environmental samples has been developed. We tested several systems for concentrating viral particles by adding adenoviruses 2 and 12 to different sewage samples. The method selected was as follows: centrifugation of the sample in order to pellet adenovirus viral particles and all suspended solids, elution of the pelleted viruses by treatment with 0.25N glycine buffer pH 9.5, removal of solids from the sample by a short centrifugation and ultracentrifugation of the resulting supernatant. Elution with glycine buffer avoided inhibitors and showed more sensitivity than ultrasonication or filtration through a low binding protein filter to retain bacteria and suspended solids. Sewage samples were treated by this selected method and recovered viral particles were analyzed both by a two-step DNA amplification reaction and by infecting Hep-2 cells. About 50% of the samples were positive in a two-step PCR and these data were confirmed by tissue culture amplification and one step PCR. Two pairs of primers (external and nested) from the hexon region were used, which are able to detect human adenovirus from all subgenera. Although more studies are needed, the two-step PCR developed appears to be a quick and reliable method for adenovirus detection in environmental samples.
... Protozoa and enteric viruses are of specific concern in wastewater reuse as they generally pose a greater challenge than bacteria in wastewater treatment, and the risk of infection can be 10 to 1,000 times higher than for bacteria at a similar level of exposure (189). Highly infectious bacteria like Campylobacter (231) and enterohaemorrhagic E. coli, EHEC (229), are notable exceptions. ...
... In addition, uptake of plant nutrients in reclaimed wastewater and reduction in fertilizer use may prevent surface water and/or groundwater contamination (Sanderson, 1986). Potential disadvantages of using reclaimed wastewater include accumulation of phytotoxic levels of heavy metals (Omranet al., 1988), high salinity (Basiouny, 1982), and concern over the health risk associated with viruses and bacteria in the water (Brenner et al., 1988;Gleason et al., 1984;Rose and Gerba, 1991). ...
Article
An experiment was designed to determine the effects of canal water and reclaimed wastewater on growth, yield, and fruit quality of mature (25-year-old) `Redblush' grapefruit (Citrus paradisi Macf.) trees on sour orange (C. aurantium L.) rootstock. The study was conducted from 1 Oct. 1990 to 18 Apr. 1994 at a site adjacent to the Indian River County municipal wastewater treatment facility located near Vero Beach, Fla. Treatments included canal water applied based on one-third or two-thirds soil water depletion and reclaimed wastewater applied using microsprinklers at 23.1 mm/week (low), 30.7 mm/week (moderate) and 38.6 mm/week (high). Trees receiving low and moderate levels of reclaimed wastewater had the largest canopies and trunk diameters and highest yields, even though the amount of fertilizer applied was less than that of canal water plots. Leaf nutrient levels were generally within acceptable ranges for N, P, K, Ca, Mg, and Na except in 1991 when levels were deficient due to excessive rainfall and leaching. Leaf B levels were similar for all reclaimed wastewater treatments but were lower for the canal water treatment in 1992 and 1993. Fruit growth rate, fruit and juice weight, total soluble solids (TSS), titratable acidity (TA), and TSS: TA ratio were similar for all treatments in 2 of 3 years. Peel thickness was similar for all treatments. Heavy metal concentration in the reclaimed wastewater was at low or nondetectable levels. Similarly, enteric viruses in the effluent were always <0.003 plaque forming units/liter. Reclaimed wastewater irrigation significantly increased weed growth compared to the canal water treatment.
... These enteric viruses multiply in the intestinal tract and are released in the faecal matter of infected persons. From the standpoint of health, the most important human enteric viruses are the enteroviruses, Norwalk viruses, rotaviruses, reoviruses, caliciviruses, adenoviruses and hepatitis A virus (Rose and Gerba, 1991;Absar, 2005). Sedimentation, filtration and disinfection, if used efficiently, usually provide acceptable virus removal (EPA, 1996). ...
Article
Full-text available
The reuse of treated effluent (for agriculture and as supplement for drinking water needs) is currently receiving attention as a reliable water source. This paper is aimed at reviewing the environmental and health impacts of untreated or inadequately treated wastewater effluents. The quality of wastewater effluents is responsible for the degradation of the receiving water bodies. This is because untreated or inadequately treated wastewater effluent may lead to eutrophication in receiving water bodies and also create environmental conditions that favour proliferation of waterborne pathogens of toxin-producing cyanobacteria. In extension, recreational water users and anyone else coming into contact with the infected water is at risk. Although various microorganisms play many beneficial roles in wastewater systems, a great number of them are considered to be critical factors in contributing to numerous waterborne outbreaks. Also, wastewater effluents have been shown to contain a variety of anthropogenic compounds, many of which have endocrine-disrupting properties. Since large amounts of wastewater effluents are passed through sewage treatment systems on a daily basis, there is a need to remedy and diminish the overall impacts of these effluents in receiving water bodies. In order to comply with wastewater legislations and guidelines, there is a need for adequate treatment before discharge. This can be achieved through the application of appropriate treatment processes, which will help to minimize the risks to public health and the environment. To achieve unpolluted wastewater discharge into receiving water bodies, careful planning, adequate and suitable treatment, regular monitoring and appropriate legislations are necessary.
... Agricultural reuse of wastewater becomes the potential irrigation water in the big cities and urban. The water resources from secondary treatment contain the residual viruses and pathogens, which can persist to varying degrees after release to the environment ( Rose and Gerba, 1991). Hence, the effluent wastewater is required special care before irrigating the crops for direct human consumption (WHO, 1973). ...
Conference Paper
Full-text available
Irrigation water and recycled water used for farm gardens can be a potential source of contamination of microbial pathogens that cause harmful illness. This study investigated the use of pressurized carbon dioxide to inhibit pathogens in water sources. An apparatus producing microbubbles was operated with pressure up to 0.7 MPa, room temperature and a common period for disinfection, 25 minutes. Target environmental water samples, including distilled water, artificial ground water and effluent wastewater, were subjected to microbial contamination with desired concentrations of Escherichia coli (ATCC 11303 and ATCC 13965) and bacteriophages. Under identical conditions, approximately 4.0 – 5.0 log of E. coli were inactivated in water samples, whereas the reduction ratio of bacteriophages are nearly 3.0 – 4.0 log. The chemical nature of CO2 molecule (acidification, diffusivity and solubility in water) was indicated to be the main factors causing the microorganism deaths. Besides that, high pressure, depressurization rate, characteristics of microbubbles and pumping cycle contributed to microorganism inhibition. These findings in this investigation may be considered to use carbon dioxide as a novel disinfectant to water treatment in agricultural irrigation. Moreover, carbon dioxide treatment produces no disinfection by-products and excessive pressure after disinfection can be an advantage to enhance irrigating to plants.
... Ultraviolet treatment or chlorination). Well operated treatment plants will produce a quality of reclaimed water suitable for non-restricted irrigation, however these waters contain low levels of pathogens and limitations on human exposure is advised (Rose & Gerba 1991:2097. Limits are set on such parameters as faecal coliforms, total coliforms, viruses, parasites, suspended solids, turbidity, and biochemical oxygen demand (BOD) (Thomas 1999:13), and specific parameters and values will vary between different sets of guidelines. ...
Article
Placing the phenomena of urban water reuse in context introduces a range of social, political and economic issues which arise from the balancing act of satisfying human needs while maintaining some protection for the natural environment. This paper draws from the first year of research on the topic: Community perceptions of water r euse: a critical analysis which has involved a basic orientation to the concept of urban water reuse. Initial field work has been completed at New Haven, in Adelaide, and interviews are currently being conducted with a c omparative population at Mawson Lakes. However, the focus of this paper is the context: the main drivers of the technology, standard treatment, regulations and some of the historical and current applications which provide the foundation for the research.
... The reclamation and reuse of the secondary wastewater or domestic effluents can be a good alternative for securing water sources in such regions. However, those effluents usually contain a certain level of organic contaminants and pathogenic microorganisms like enteric viruses and protozoan parasites causing health risks [1,2]. Recently, organic and microbial contamination has been a matter of greater concern in accordance with meeting stringent regulations of discharge levels. ...
Article
Filtration experiments using a bench-scale immersed membrane separation system combined with PAC (powdered activated carbon) were conducted in order to investigate the effects of PAC on the efficiencies of operation and treatment and to evaluate the performance of the system. The experiments were carried out under such operation conditions as a filtration rate of 1 m/d (or 42 l/m2/h), water temperature of 20–25°C, and PAC dose of 0 g/l (PAC-0), 10 g/l (PAC-10) and 40 g/l (PAC-40). Synthetic secondary wastewater was used as a raw water; the influent concentrations of TOC (total organic carbon), UV254 (UV absorbance at 254 nm) and NH4+-N (ammonia nitrogen) were 9.09 mg/l, 16.4 1/m and 5.0 mg/l, respectively. TOC removal of 51, 74 and 83%, and UV254 removal of 63, 89 and 95% were obtained for PAC-0, PAC-10 and PAC-40, respectively. Ammonia oxidation was observed only for PAC-40, which started to occur on the 20th d from the operation and was completed in 25 d. Average filtration times up to TMP (transmembrane pressure) of 70 kPa were 32, 61 and 97 h for PAC-0, PAC-10 and PAC-40, respectively. The amounts of organic compounds attached to the membrane pore were 380, 280 and 64 mg of TOC per 1 m2 of membrane surface area for PAC-0, PAC-10 and PAC-40, respectively. This study found that the filtrate quality and the performance efficacy were enhanced with the increase in the concentration of PAC introduced into the filtration system.
... The percent of the swimming-associated illnesses attributable to each of the reference pathogens was based on data published by the CDC (Mead et al., 1999). The doseeresponse relationships were based on the peer reviewed literature (Crabtree et al., 1997;Haas et al., 1999;Regli et al., 1991;Rose and Gerba, 1991;Teunis et al., 2005Teunis et al., , 2008aTeunis et al., , 2008bU.S. EPA, 2006). The percent of infections resulting in illness was based on the results of a comprehensive literature review that was conducted during the course of previous work (Soller et al., 2007a;Soller and Eisenberg, 2008) and supplemented with newer data for Norovirus (Teunis et al., 2008a). ...
Article
Epidemiology studies of recreational waters have demonstrated that swimmers exposed to faecally-contaminated recreational waters are at risk of excess gastrointestinal illness. Epidemiology studies provide valuable information on the nature and extent of health effects, the magnitude of risks, and how these risks are modified or associated with levels of faecal contamination and other measures of pollution. However, such studies have not provided information about the specific microbial agents that are responsible for the observed illnesses in swimmers. The objective of this work was to understand more fully the reported epidemiologic results from studies conducted on the Great Lakes in the US during 2003 and 2004 by identifying pathogens that could have caused the observed illnesses in those studies. We used a Quantitative Microbial Risk Assessment (QMRA) approach to estimate the likelihood of pathogen-induced adverse health effects. The reference pathogens used for this analysis were Norovirus, rotavirus, adenovirus, Cryptosporidium spp., Giardia lamblia, Campylobacter jejuni, Salmonella enterica, and Escherichia coli O157:H7. Two QMRA-based approaches were used to estimate the pathogen combinations that would be consistent with observed illness rates: in the first, swimming-associated gastrointestinal (GI) illnesses were assumed to occur in the same proportion as known illnesses in the US due to all non-foodborne sources, and in the second, pathogens were assumed to occur in the recreational waters in the same proportion as they occur in disinfected secondary effluent. The results indicate that human enteric viruses and in particular, Norovirus could have caused the vast majority of the observed swimming-associated GI illnesses during the 2003/2004 water epidemiology studies. Evaluation of the time-to-onset of illness strongly supports the principal finding and sensitivity analyses support the overall trends of the analyses even given their substantial uncertainties.
... Availability of water for irrigation is one of the most important factors in arid and semiarid regions, and treated domestic wastewater becomes an important source. More than 365 x 10 6 m 3 per year of wastewater is used for irrigation in the US (Rose and Gerba, 1991). More than 70% of Israel sewage is treated and reused in agriculture irrigation. ...
Article
Full-text available
The objective of this work was to compare and simulate transport and fate of microorganisms from wastewater for surface and subsurface irrigation methods. Adsorption isotherms and water-content dependent survival were measured for fecal coliforms, somatic coliphages and F-specific RNA phages in batch experiments with treated wastewater and clay loam soil. Column experiments with surface and subsurface trickle irrigation were carried out for the same soil. Results of the column experiments were simulated with a combination of Richards equation for water transport and advective-dispersive model with the first-order nonlinear adsorption and moisture-dependent first-order die-off. Simulations showed that die-off rates in column experiments were much higher than in batch experiments for all three organisms. Somatic coliphages were the most persistent organisms probably because of lower adsorption and die-off. The subsurface irrigation appeared to be efficient in decreasing the number of pathogens in irrigated water and preventing their appearance on soil surface that could lead to produce contamination.
... Viral removal after treatment has an epidemiological importance depending on the high resistance of viruses to the treatments if compared with bacteria (Rose et al. 1996;Nasser and Oman 1999). Enteric viruses include Enteroviruses, Hepatitis A virus, Calicivirus, Rotavirus, Adenovirus and Astrovirus and they are responsible for a large number of epidemics because of their presence in the aqueous environment or food (Rose and Gerba 1991;Sánchez et al. 2002;Martinelli et al. 2006;Torner et al. 2008). ...
Article
The aim of the work was to evaluate the circulation of the viruses and to determine a correlation between faecal indicators and viruses. Raw wastewater and effluent samples were collected from three wastewater treatment plants, during three sampling periods, and analysed, using cultural and molecular methods, to determine bacteria and virus presence. The results show a removal of bacterial indicators, but a limited reduction of the phages. The viral analysis displays the circulation of cultivable enteroviruses and differences in the seasonal-geographical distribution. Hepatitis A virus was found with only two genotypes: IA-IB. Rotavirus was present in 11.11%, 24.14%, 2.78% of the samples in the 1st, 2nd and 3rd sampling periods; Astrovirus in 33.33%, 6.9%, 25%; Adenovirus in 7.41%, 3.45%, 2.78%; Norovirus in 7.41%, 10.34%, 5.56% respectively. Adenovirus was never identified in plants B and C as Rotavirus in plant C. The presence of faecal indicators was not predictive of the enteric virus presence, whereas a different circulation of Enteroviruses was found in the wastewater treatment plants. The study shows the importance and the usefulness of molecular methods to evaluate the virus circulation and the genetic variability of Enteroviruses.
A quantitative microbial risk assessment (QMRA) was conducted to support renewal of the City of Vacaville wastewater discharge permit and seasonal (summer) filtration requirements. Influent and final disinfected effluent from the city’s wastewater treatment plant, as well as 11 receiving water stations, were monitored for indicator organisms (i.e. total and fecal coliforms, Escherichia coli, Enterococcus, male-specific bacteriophage (MS2), and the Bacteroidales) and several pathogens (i.e. Giardia cysts, Cryptosporidium oocysts, infectious Cryptosporidium, and Norovirus GI and GII). QMRA annualized risks of infection for selected pathogens enteric viruses, Giardia and Cryptosporidium. Estimated median annualized risk for recreational exposure in either disinfected secondary and/or filtered disinfected secondary effluent is on the order of 1.1 × 10³ per person per year (pppy) for enteric viruses and would be roughly one order of magnitude lower if local receiving water dilution of the treatment plant effluent was taken into account. Estimated median annual risk for recreation exposure in disinfected secondary effluent is 1.8 × 10³ pppy for Cryptosporidium and 1 log10 less with filtration during the summer months. The estimated median annual risk for landscape exposure (e.g. golfing) to secondary disinfected effluent is 7.6 × 10⁷ pppy for enteric viruses. Estimated median annualized risk is 1.7 × 10⁷ pppy for enteric viruses and 3.0 × 10⁵ to 3.6 × 10⁶ pppy for parasites for use of secondary disinfected effluent with irrigated agriculture. Estimated annualized risks for recreational exposure to the local receiving waters were approximately 10 to 1,000 times greater than direct recreational exposure to the final filtered and disinfected effluent. All risk estimates associated with exposure to final treated plant effluent (i.e. secondary filtered and disinfected) were close to or lower than the California level of acceptable annual risk of infection of 10⁴ pppy for recreational exposure. Risk estimates provide further evidence to support the use of seasonal treatment limits requiring summer filtration for public health protection.
Article
Wastewater treatment represents a continuous challenge for engineers, environmental scientists and regulators. At the beginning it was the biological load to be reduced as much as possible to prevent infections and eutrophication phenomena. Afterwards, besides domestic discharges, industrial wastewater required specific technologies and treatment facilities to allow the removal of targeted pollutants. Today, an increasing number of new contaminants are rising up such as pharmaceuticals, personal care products and nanomaterials just to cite the most recent categories. The current goal in wastewater management is to move towards the (near-) zero approach or, ideally, the zero-discharge requiring to recover and reuse treated wastewater as much as possible. About that, ecotoxicological tools may offer a great support in the defining the rate of contamination removal during the treatment processes and allow further assessment about effluent second life. An overview of ecotoxicological approaches to assess wastewater environmental impacts to saltwater is presented and discussed considering toxicity tests as essential guidelines.
Article
Water plays not only an essential role in the growth of produce, but also in in processing and hygienic uses pre- and postharvest. Ensuring the microbial quality of this water is critical to prevent contamination of produce by waterborne enteric pathogens. Contamination of produce may occur from the use of contaminated irrigation water or water to apply pesticides, fertilizers, hydro-cooling, hand-washing and icing. Several produce outbreaks have been known or suspected to have been due to the use of contaminated irrigation water. Currently, no microbial indicator standards exist for irrigation waters used for produce production in the United States. There are few studies on the occurrence of fecal bacteria in irrigation waters in the United States. Existing data indicates that levels are generally low, except after rainfall events. Sources of fecal bacteria in irrigation waters include birds, storm water runoff and domestic animals. The degree of crop contamination during irrigation depends on the methods of application i.e., spray, flood or sub-surface irrigation.
Article
The wastewater treatment is an essential practice and is one of the forefront new worldwide challenges. Indeed, the today aims in wastewater management are profoundly changing. The sanitization processes are of course essential, but now some more efforts are required not only to reduce the environmental impact of the effluent regarding the receiving water body, for example, in terms of organic load, but also to provide management practices to allow water recovery, recycle and reuse. This means that treated wastewater are new resources that may be reused according to their final level of quality. New technological facilities are available, some more are expected in the near future, and innovative scaling approaches are strongly encouraged too. Actually, sometimes extensive sewage collection systems are no more cost-effective, thus decentralisation treatment processes considering small-scale wastewater treatment plants may represent a potential solution in both developed and developing countries. Furthermore, this kind of approach will strengthen those areas that are historically affected by drought phenomena or are expected to suffer from water scarcities in the near future as a consequence of climate change. © 2013 Springer Science+Business Media Dordrecht. All rights are reserved.
Chapter
Water has always played a key role as a vehicle for the transmission of pathogens transmitted by the fecal-oral route. Several produce outbreaks have been known or suspected to have arisen from contamination in the field, suggesting contamination by irrigation or during handling. The microbial quality of irrigation water depends on the source of the water and contamination as it is transmitted through the distribution system. Contamination of produce may also occur through the use of contaminated water to apply pesticides, fertilizers, washing, hydrocooling, handwashing, and icing. It has been observed that use of contaminated hand wash water, resulting from multiple use by different individuals, can result in hand contamination by enteric bacteria. Furthermore, use of fecally contaminated water for application of pesticides or in wash water may lead to produce contamination. Although the percentage of pathogen transfer from contaminated water to produce by some types of irrigation methods (e.g., drip irrigation) may be low, risks can still be considered significant because of the low numbers of some enteric pathogens, such as viruses, necessary to cause infection. Meaningful standards for indicator bacteria that better assess the risk of produce contamination and risk of infection to the consumer need to be developed.
Chapter
The parasites Giardia duodenalis and Cryptosporidium parvum are the two most commonly reported parasites of human beings world-wide. The endemnicity of giardiasis and cryptosporidiosis, the large numbers of (oo)cysts excreted in feces, and their small size and disinfection insensitivity have implications for wastewater treatment. Giardia exists in two distinct morphological forms: the reproductive, pear-shaped trophozoite-which is non-invasive and attaches onto the enterocytes of the upper small intestine, and the environmentally resistant cyst, voided in the feces, which is the infective and disseminating stage. Both the (oo)cyst structure and the organization contribute significantly to the different requirements for control by disinfection. As the (oo)cysts settle slowly and have a specific gravity similar to that of water, insufficient retention time (RT) is available for their complete settlement and removal, unless attached to heavier particulate material. The mechanism of (oo)cyst removal is similar to that for other negatively charged particles in water. Cationic coagulants are added to the water and are mixed rapidly to reduce the large repulsive forces between negatively charged particles, and cause them to collide and form aggregates of greater mass.
Article
Full-text available
California currently recycles treated wastewater at a volume of approximately 8.0x108m3 of water per year, with a potential to recycle an additional 1.9x109m3 per year. A key challenge in promoting the expansion of water recycling for agricultural purposes was addressing the perceived concern about whether recycled water produced in conformance with California law is protective of public health. The California Department of Public Health (CDPH) established an expert panel to consider the concern. The panel found, based on quantitative microbial risk assessment (QMRA), that the annualized median risks of infection for full tertiary treatment ranges from 10-8 to 10-4 (for human enteric viruses Cryptosporidium parvum and Giardia lamblia, and Escherichia coli O157:H7) based on the assumption of daily exposure. The panel found that risk estimates are consistent with previous CDPH estimates and concluded that current agricultural water recycling regulations do not measurably increase public health risk.
Article
Full-text available
Here w report the r esults of Giardía cysts removal [rom waslewater trea tmen t. The sam ples were collecled [rom facullative pond , Al and m a turatlon pond, AJ of oxidation ponds nine system. Oth ers samples were colleded [rom hyacinth t ank, slow sand filter and trickling filter u n ils feedi ng maturation pon ds effluen ts . The sample were proseculed a ccording t o Ho el. a l (1995), with partíais modifications . Gíardia cysts were removed from hyacinth tank maturation effl u en ts. An 78,0% Giardía cysts were removed [rom slow s and fil ler units a n d 50, 0%, the from trickl1 ng fille r unils. Cysts rem oval [rom domestic wastewa ter treatment in oxldaUon ponds were 90. 9 % . Th e trea tmen ts were sign ificative (p ~ 0 .05) for the reduction of Giardia cysts o[ wastewater. Th e removal Giardia cysts were effective in oxldaUon s ponds, hyacinth tank, slow sand fil ter units and trtcklin g filter u n its.
Chapter
Two drip irrigation systems for on-surface and subsurface effluent application were installed in sweet corn (Zea mays L. var. saccharatum) experimental fields. Effects of secondary effluent on yield and bacterial contamination in the soil and the corn plants were studied. Results were compared with those obtained for sprinkle irrigated plots. Bacterial contamination of the crop was maximal under sprinkle irrigation and minimal under drip application.
Article
Several systems for virus recovery from environmental samples and extraction of nucleic acid were tested by adding adenovirus 2 and poliovirus 1 to different sewage samples. The most promising method involved: concentration of viruses by centrifugation, and elution of the pelleted viruses by treatment with 0.25 N glycine buffer pH 9.5. The nucleic acids were extracted by adsorption of RNA and DNA to silica particles. One aliquot was directly used for a two-step PCR m a nested fashion, with specific primers for all adenoviruses; the other aliquot was used to synthesize cDNA and a nested two-step PCR with specific primers for enteroviruses. The specificity and sensitivity of the selected primers were evaluated, the 47 human adenovirus serotypes were identified and 24 different enterovirus strains were recognized. The sensitivity of the nucleic acid extraction, cDNA synthesis and nested PCR amplification was estimated to be between 1 and 10 vital particles. Sewage and polluted river samples were analyzed showing, as expected, a much higher number of positive samples by the method desrnbed than by tissue culture analysis, a high prevalence of hepatitis A virus in sewage and the adenoviruses as the most commonly detected virus in the environmental samples analyzed.
Article
Monitoring data and dose-response models were used to evaluate risks associated with viruses and protozoa at a full-scale reclamation facility. Indigenous indicator and pathogenic microorganisms were monitored at different stages of treatment for 1 yr at a full-scale water reclamation facility that produced reclaimed water for residential irrigation. The combination of biological treatment, sand filtration, and chlorination employed at the plant reduced total and fecal coliforms by > 7 log10 and coliphages and enteroviruses by > 5 log10. Protozoa (Cryptosporidium and Giardia spp.) were reduced by > 3 log10. Viruses and protozoa were detected in the reclaimed water at levels between 0.01 and 5 per 100 l. The addition of large numbers of bacteriophage as a tracer permitted an assessment of inactivation and/or removal by the filtration and chlorination units, which were shown to provide 1.6 and 1.5 log10 reductions, respectively. Analysis of the risk associated with exposure to the reclaimed water shows that the probability of infection following a single exposure to 100 ml of the water was between 10−6 (1 in a million) and 10−8 (1 in 100 million) for landscape irrigation. In general, anaerobic treatment of residual solids produced during the wastewater treatment process reduced the levels of indicator and pathogenic microorganisms by approximately 1 log10. The levels of viruses detected in the final residual would not meet acceptable levels for land application for class A residuals according to EPA regulations.
Article
Membranes are finding increasing applications in disinfection processes including virus removal from water for municipal effluent reuse. The capability of virus removal from water by microfiltration membranes has previously been demonstrated. In this study, the capability of fuzzy logic for modeling and simulation of dead-end microfiltration process for removal of IBR and FMD viruses from water was elucidated. The main parameters indicating membrane performance i.e. flux and rejection were experimentally obtained under different conditions and compared with theoretically calculated flux and rejection using fuzzy inference system. The genetic algorithm which is an efficient and systematic method was employed in the design of fuzzy model for optimization of the poorly understood, irregular and complex membership function with improved performance. Hybrid genetic algorithm was used for optimizing the parameters that are located at the Gaussian membership functions in the premise and consequent of each rule.The results indicated that fuzzy inference system predicts the key parameters i.e. flux and rejection for different operating conditions with an acceptable error. In other words FIS is able to apply for modeling the microfiltration membrane which is mathematically difficult or in many cases an unpredictable process.
Article
This paper provides the background to the development of the Australian guidelines for the use of reclaimed water. USEPA and WHO guidelines are discussed. The current draft guideline format is outlined. This includes values for thermotolerant coliforms set at four levels for a variety of applications depending on degree of human contact. Levels of treatment are recommended along with safeguards for particular applications.
Article
Full-text available
The need for alternative sources of water, especially for non-potable purposes, has been met in many states in the US and throughout the world through the use of reclaimed wastewater. Wastewater contains a wide variety of microbial pathogens that may pose a risk to human health if not properly controlled; however, there are currently no national standards for microorganisms or consistent treatment requirements in the US with regards to reclaimed water. Besides the routine monitoring for TC and FC bacteria that has been used for assessing water quality, several types of alternative microorganisms have been suggested as indicators of water quality, fecal pollution, and public health risks. These include enterococci, Clostridium perfringens, and coliphage among others. This project evaluated the removal of both indicators (TC and FC, enterococci, C. perfringens and coliphage) and pathogens (enteroviruses, Giardia spp. and Cryptosporidium spp.) at 3 water reclamation facilities with varying treatment designs and operations. The facilities evaluated range in size from 20 to 44 million Liters per day capacity, with both shallow and deep bed sand/anthracite filters. Differences also existed in the disinfection processes for the 3 reclamation plants. The TC and FC showed a 5 to 7 log reduction throughout the treatment processes with no detectable levels in the final effluent. However, even though the alternative indicators (enterococci, C. perfringens and coliphage) showed reductions that varied from 2 to 6 logs, some levels of these indicators were consistently detected in 2 of the 3 facilities in the final reclaimed effluent. Both Cryptosporidium spp. and Giardia spp. were detected in the final effluent in all 3 facilities, even when no indicators were present. Virus detection was seasonal, and associated with cooler temperatures and less disinfection. The results of this study indicate that differences in filter design, operations, and disinfection approaches were responsible for
Article
The current annual risk of acquiring a foodborne disease in the United States is estimated at 2.7 × 10-2. The risk of associated death is estimated at 3.7 × 10-5. These represent a health care burden >$3 billion. Using a risk assessment model one can identify levels of microbial contamination which may be unacceptable in foods and appropriate controls needed to reduce these levels. Salmonella bacteria continue to represent a large percentage of the identifiable infections. A model developed from human dose-response studies predicts the probability of infection for Salmonella at 7.5 × 10-3 with exposure to a single CFU of the organism. Risks of severity (hospitalization), mortality, reactive arthritides, and mortality in the elderly are estimated at 3.1 × 10-6, 7.5 × 10-6, 1.7 × 10-5, and 2.8 × 10-4. Exposure to microbial contaminants needs to be evaluated on a single meal basis. For chicken, exposure may range from a single drum stick (38g) to a half broiler (176g) but averages around 80g. For beef between 51 and 85g may be consumed during a single meal. Therefore, methods for monitoring must be able to detect at least 1 CFU/80g. Risks for some pathogenic E. coli are estimated at 1,000 to 10,000 less than Salmonella. Therefore, use of coliforms as indicators needs to be assessed and related to occurrence and survival and regrowth potential of the enteric bacteria of greater public health concern. Because, 20% of the U.S. population may be considered to be in a special population category and at an increased risk of severe outcomes, no more than 20% failure of a standard should be acceptable.
Article
The use of Serratia marcescens bacteriophage as a tracer and a model for virus removal in the Cayman Islands' waste stabilisation ponds was investigated. A series of bench-scale experiments was designed and carried out to determine the survival of Serratia marcescens bacteriophage in the various stages of a waste stabilisation pond system. The study investigated whether the physico-chemical conditions expected in facultative and maturation ponds precluded the use of phage tracers. By the end of the 6th day, phage in filtered and unfiltered raw sewage and facultative pond samples, in normal sunlight, was undetectable. In the maturation pond samples,in normal sunlight, phage was undetectable by the 4th day. There was a high correlation between increased phage reduction and increased pH levels. The phage was still detectable on day 13 in maturation pond experiments kept in the dark. Therefore the study concluded that Serratia marcescens bacteriophage may be useful as a tracer in ponds with retention times up to 14 days provided average pH at the outlet is <9.0.
Article
Freie Gewässer enthalten oft Krankheitserreger, die durch diffuse und punktuelle Abwassereinleitungen, Regenüberläufe, Regenabschwemmungen u. a. m. eingetragen werden. Daher besteht beim Baden in freien Gewässern ein gewisses Infektionsrisiko. Andererseits erfreut sich das Baden in freien Gewässern zunehmender Beliebtheit, bieten doch Badeereignisse einen intensiven Kontakt zu Landschaft und Natur mit hohem Erholungswert. Das Risiko, sich beim Baden zu infizieren, muß daher gegen den gesundheitlichen Nutzen der Erholung abgewogen werden. Dabei sind Ziele, freie Gewässer vollkommen frei von Krankheitserregern zu halten, unrealistisch. Vielmehr muß versucht werden, die Kosten für die Sauberhaltung von Badegewässern mit dem Nutzen der Prävention von badebedingten Infektionen in Beziehung zu setzen. Zu diesem Zweck muß die Gesellschaft überinkommen, wie viele badebedingte Infektionen sie bereit ist, in Kauf zu nehmen (z. B. pro Anzahl Badender und Saison). Anschließend müssen mit naturwissenschaftlichen Methoden diejenigen Grenzwerte von Fäkalindikatoren, die dem akzeptierten Risiko entsprechen, abgeleitet werden. In dieser Arbeit werden zwei Wege für die Ableitung von gesundheitsbezogenen Grenzwerten vorgestellt. Der erste Weg geht von empirisch festgestellten Dosis/Wirkungsbeziehungen (z. B. durch Probandenstudien) für bestimmte Krankheitserreger aus. Daraus lassen sich für einzelne Krankheitserreger die Infektionswahrscheinlichkeiten beim Baden ermitteln und, wenn das Verhältnis von Indikatororganismen zu Krankheitserregern bekannt ist, Indikatorgrenzwerte festlegen. Der zweite Weg geht von der epidemiologischen Bestimmung der Erkrankungsrate in Abhängigkeit zum Fäkalindikatorengehalt von Badegewässern aus. Weil die Konzentration von Fäkalindikatoren in Badegewässern nicht konstant, sondern lognormal verteilt ist, müssen bei der eigentlichen Berechnung des Baderisikos die Parameter dieser statistischen Verteilung auch berücksichtigt werden. Beide Ansätze können für eine rationale Ableitung von Grenzwerten herangezogen werden. Gemäß ihrer unterschiedlichen Ableitungsprinzipien erfordert ihre Anwendung die Erarbeitung unterschiedlicher Grundlagen. Für Deutschland wird die rationale Ableitung von mikrobiologischen Grenzwerten über beide Wege dadurch erschwert, daß weder genügend Erkenntnisse zum Verhältnis von Krankheitserregern zu Fäkalindikatoren vorliegen, noch epidemiologische Studien zum Infektionsrisiko beim Baden durchgeführt worden sind. Untersuchungen in anderen Ländern deuten darauf hin, daß die zur Zeit gültigen Grenzwerte nicht ausreichend sind. Diese Ergebnisse lassen sich jedoch nur mit Vorbehalt auf Deutschland übertragen. Frequently the same free natural waters are used for swimming and other recreational activities as well as for the discharge of multiple sources of fecal pollution, for example point and non-point discharges of sewage, sewage pipes overflow valves, runoff of contaminated rain water. This results in a certain risk of infection for bathers, which has to be weighed against the recreational value of using the free waters. Goals directed towards quantitatively eliminating fecal pollution must, as a rule, be discounted as unrealistic. Rather, attempts must be made to balance the risk of getting infected against the advantages (for health, recreation, etc.) of relatively clean waters. In doing so, society has to decide as to how many waterborne infections it might be ready to tolerate and, subsequently, determine the values of bacteriological fecal pollution standards which correspond to the accepted risk. In this paper we deal with two approaches for developing health related bacterial standards. The first approach leads to the development of standards starting from the odds of infection with a pathogen that is present in the bathing water. This approach requires that the numerical ratio between the pathogen in question and the fecal indicators in the water are known. Additionally the relationship between the number of pathogens ingested and the probability of being infected must have been previously established (in form of, e. g., studies in volunteers). The second approach for the development of standards directly uses the relationship observed between the ratio of diease among bathers and the concentration of fecal indicators in the waters. Additionally it takes into account the statistical distribution of the fecal indicators in the water. Both approaches can help to rationally develop bacterial standards, but their application requires different kinds of preliminary work. In Germany the application of either procedure is hampered because there is insufficient data regarding the ratio of pathogens to bacterial indicators in free waters, nor have epidemiological studies of bathers been carried out. At the present time no statement can be made on the adequacy of the current bacteriological standards for bathing waters in Germany. Epidemiological studies which have been carried out in other regions and might therefore not be transferable suggest that the standards might be insufficient.
Article
Field experiments were conducted to verify the hypothesis that soil performs as a complementary biofilter for secondary domestic treated wastewater disposal. The soil surrounding a subsurface point source functions as a biofilter for effluent used in agricultural irrigation. This hypothesis was examined in an outdoor experiment in which poliovirus was injected into the subsurface drip irrigation system. According the results, high virus concentration in applied effluent resulted in a very limited penetration into tomato plants via the roots. However, no viruses were detected in the leaves and the fruits.
Article
Urine separating sewerage systems have been promoted since urine contributes the major amounts of nitrogen (80%) and phosphorous (55%) to household wastewater, while only constituting 1% of the volume. To evaluate potential health risks from enteric viruses in stored urine used in agriculture, source-separated urine (pH 9) was challenged with rhesus rotavirus and Salmonella typhimurium phage 28B and their persistence followed over time. No significant inactivation of either rotavirus or the phage occurred at 5°C during 6 months of storage, while the mean T90 values at 20°C were estimated at 35 and 71 days for rotavirus and the phage, respectively. In pH controls (pH 7), the inactivation of rotavirus was similar to that in urine at both temperatures, whereas no decay of the phage occurred at either 5 or 20°C. Therefore, rotavirus inactivation appeared to be largely temperature-dependent, whereas there was an additional virucidal effect on the phage in urine at 20°C (pH 9). Hence, risks from enteric viruses are likely to be dictated by the proportion of faecal cross-contamination and the urine storage time and temperature. If stored at 20°C for at least 6 months, urine may be considered safe to use as a fertilizer for any crop.
Article
Nucleic acid hybridization has been used to detect viral nucleic acid in water. This type of assay, in contrast with tissue culture assays, may not distinguish between viable and non-viable viruses. We evaluated, by comparison with tissue culture infectivity assay (plaque forming method), the ability of the gene probe assay to detect viable poliovirus 1 (LSc) in well water, autoclaved well water, filter-sterilized well water and autoclaved phosphate buffered saline kept at 37 and 15°C for 75 days, and in dechlorinated tap water held at room temperature. A gradual decline in numbers of poliovirus was observed in all of the samples by cell culture assay. With the exception of autoclaved well water and phosphate buffer, a parallel decline in virus detectable by gene probe occurred in all other water samples. These results suggest that detection of poliovirus 1, by gene probe, is influenced by the presence of microorganisms or their products and to a lesser extent by temperature. This suggests that in some natural waters, the detection of poliovirus 1, by gene probe, may be expected to correlate to detection by tissue culture.
Article
Recent studies have revealed complex interactions among grapevine rootstocks, soil water status, and water quality in terms of yield and growth. Understanding these interactions is essential to optimise yield and its quality, especially in regions with limited or degraded water resources. Thus, a study was conducted to investigate the effect of rootstock (41B, 1103P, and 110R), irrigation level (0.50, 0.75 and 1.00 of ET, evapotranspiration), and water quality (fresh and recycled water) on vegetative characteristics and on yield quantitative and qualitative components of potted Soultanina vines for a 3-year-period. Vine growth was inhibited by irrigation with recycled water and that inhibition became more severe by increasing the irrigation level and from one season to the next season. Furthermore, recycled water reduced yield by 50% and grape juice from these vines exhibited higher pH and titratable acidity values and lower total soluble solids. Rootstock significantly affected shoot growth, an effect which varied with age and within the growing season. Vines grafted on 41B developed more leaf area and produced higher yield than vines grafted on the other two rootstocks. Decreasing in the irrigation level dramatically reduced all vegetative parameters without affecting fruit quality and yield components. A significant interaction was detected between rootstock and irrigation level in terms of yield. Vines on 41B produced the highest yield of vines irrigated at 1.00 ET, and produced higher yields than vines grafted on 110R when irrigated at 0.75 ET, but the differences in yield among rootstocks disappeared at the 0.50 ET level.
Article
The development of innovative water disinfection strategies is of utmost importance to prevent outbreaks of waterborne diseases related to poor treatment of (drinking) water. Recently, the association of silver nanoparticles with the bacterial cell surface of Lactobacillus fermentum (referred to as biogenic silver or bio-Ag(0)) has been reported to exhibit antiviral properties. The microscale bacterial carrier matrix serves as a scaffold for Ag(0) particles, preventing aggregation during encapsulation. In this study, bio-Ag(0) was immobilized in different microporous PVDF membranes using two different pre-treatments of bio-Ag(0) and the immersion-precipitation method. Inactivation of UZ1 bacteriophages using these membranes was successfully demonstrated and was most probably related to the slow release of Ag(+) from the membranes. At least a 3.4 log decrease of viruses was achieved by application of a membrane containing 2500 mg bio-Ag(0)(powder) m(-2) in a submerged plate membrane reactor operated at a flux of 3.1 L m(-2) h(-1). Upon startup, the silver concentration in the effluent initially increased to 271 μg L(-1) but after filtration of 31 L m(-2), the concentration approached the drinking water limit ( = 100 μg L(-1)). A virus decline of more than 3 log was achieved at a membrane flux of 75 L m(-2) h(-1), showing the potential of this membrane technology for water disinfection on small scale.
Article
Full-text available
A procedure has been developed for the rapid detection of enteroviruses and adenoviruses in environmental samples. Several systems for virus concentration and extraction of nucleic acid were tested by adding adenovirus type 2 and poliovirus type 1 to different sewage samples. The most promising method for virus recovery involved the concentration of viruses by centrifugation and elution of the virus pellets by treatment with 0.25 N glycine buffer, pH 9.5. Nucleic acid extraction by adsorption of RNA and DNA to silica particles was the most efficient. One aliquot of the extracted nucleic acids was used for a nested two-step PCR, with specific primers for all adenoviruses; and another aliquot was used to synthesize cDNA for a nested two-step PCR with specific primers for further detection of seeded polioviruses or all enteroviruses in the river water and sewage samples. The specificity and sensitivity were evaluated, and 24 different enterovirus strains and the 47 human adenovirus serotypes were recognized by the primers used. The sensitivity was estimated to be between 1 and 10 virus particles for each of the species tested. Twenty-five samples of sewage and polluted river water were analyzed and showed a much higher number of positive isolates by nested PCR than by tissue culture analysis. The PCR-based detection of enteroviruses and adenoviruses shows good results as an indicator of possible viral contamination in environmental wastewater.
Article
Standard methods for detecting enteroviruses in environmental samples require cell culture, which is time consuming and expensive. The reverse transcription-polymerase chain reaction (RT-PCR) is a rapid, sensitive method for detecting enteroviruses in water. However, environmental samples often contain substances that inhibit PCR amplification of target RNA. Hence the virus must be concentrated by procedures that do not interfere with amplification. This study shows that virus concentration by adsorption onto glass powder or glass wool supports is suitable for detecting viral genomes in treated wastewater by RT semi-nested PCR. No enterovirus genome was detected directly in 25 samples of treated wastewater by RT semi-nested PCR. However, samples concentrated by adsorption onto glass wool or glass powder showed that 48% (glass powder) and 56% (glass wool) contained virus. Secondary concentration by organic flocculation was unsuitable for detecting virus concentrated on glass wool (20% positive samples), but it helped to increase the detection of the genome after concentration on glass powder (72% positive samples).
Book
A book in environmental sciences prepared for students in Indian Universities as part of CBCS curriculum. book comprises of seven units, namely, Introduction to Environmental Studies, Ecosystems, Natural resources, Biodiversity and conservation, Policies and practices and Human communities and environment.
Chapter
The removal/inactivation of viruses during sewage treatment is reviewed. Almost all of our current knowledge on enteric virus removal is limited to enteroviruses, and research is needed on the removal of other enteric viruses during sewage treatment. Primary treatment removes 0-50% of the viruses initially present, while secondary treatment (biological) can be expected to remove 90-99%. Rotaviruses may not be as effectively removed by secondary sewage treatment as enteroviruses. Tertiary treatment involving chemical coagulation can be expected to further remove large numbers of viruses.
Article
A watershed in the western United States was surveyed biweekly for a year for the protozoa Cryptosporidium and Giardia. Parasite samples were collected using filtration of 200-1000 L of water, eluted by washing the filter, concentrated and clarified with density gradients. Oocyst and cysts were detected using monoclonal antibodies, in a direct or indirect immunofluorescent assay. The organisms were enumerated on membrane filters using epi-fluorescent microscopy. Number of organisms per liter of water were then calculated. Grab samples were analyzed for total and fecal coliform concentrations as well as turbidities. After log10(y+1.0) transformations, Pearson's correlation coefficients were derived for each variable against all others. From 39 samples, Cryptosporidium and Giardia were detected in 20 and 12 of the samples, respectively, and oocyst concentrations were approximately 10 times higher than cyst levels. The river downstream from the lake ran through an area concentrated with cattle pasture and had the greater numbers of both parasites (1.09 oocysts and 0.22 cysts/L). The lake, although receiving sewage effluents, may have also had lower levels (0.58 oocysts and 0.08 cysts/L) because of dilution and sedimentation. Coliform levels ranged from 0.12 to 75 CFU/l00ml while fecal coliform levels were slightly lower. Turbidity averaged 55 NTU at the river and 48 NTU at the lake. Correlation coefficients were derived for all variables. Giardia concentrations were significantly correlated to Cryptosporidium concentrations with an r value of 0.778, significant at the 99% confidence level. No other correlations were observed between Giardia and total or fecal coliforms or turbidities nor between Cryptosporidium levels and total or fecal coliforms or turbidities. Neither bacterial indicator organisms nor turbidity are reliable predictors for the absence of enteric protozoa in the study watershed.
Article
This article is intended to serve as a guide for those who evaluate water treatment plants with the objective of lowering the turbidity of finished water produced from filtration plants in which chemical coagulation is part of the treatment process. Ineffective removal of turbidity may be related to several factors, including the physical condition of the facilities, the hydraulics of treatment processes, the quality of water, and the competence of the operating staff. By preplanning, the evaluation can be conducted in a logical fashion that results in consideration of all necessary and important aspects of the plant and its operation. Descriptions of the proper operation of each component in the process train and pragmatic remedies to improve performance are given. Este artículo tiene la intentión de ser un guía para personas que evalúan plantas de tratamiento de agua con el objetivo de bajar la turbidez de agua terminada producida en plantas de filtratión en las cuales coagulatión química es parte del proceso de tratamiento. Remoción inefectiva de turbidez puede ser relacionada a varios factores, incluyendo la conditión física de las facilidades, las hidráulicas de procesos de tratamiento, la calidad de agua y la competencia del personal. Planificando con anterioridad, la evaluatión puede ser conducida de una manera lógica que resulta en consideratión de todos los aspectos necesarios e importantes de la planta y su operatión. En este artículo se dan descripciones de las operaciones correctas de cada componente de la cadena de procesos y soluciones pragmáticas para mejorar la ejecución.
Article
In many arid environments an alternative source of water is needed to meet the growing demands of the community, agriculture, and industry, thus wastewater reuse has become a viable option. Although the use of wastewater for agricultural irrigation has been practiced for centuries, recently a conservative approach in fully utilizing this source of water has been taken. The uncertainty of the health risks to an exposed population through wastewater irrigation practices due to the possible presence of enteric pathogenic organisms is one of the major disadvantages. Pathogenic bacteria, parasites, and viruses are all found in sewage and may survive treatment processes. Once in the environment, many are able to exist for prolonged periods of time and outbreaks associated with wastewater irrigation have been documented. Epidemiological evidence is scarce, however, much has been done to determine the fate of the pathogens in the environment. The incidence, survival, and inactivation of pathogens in environments associated with the wastewater aid in the understanding of the sudden occurrence of epidemics and potential routes of transmission. The scope of this review includes epidemiological studies on populations exposed to wastewater, the microbial survival on crops irrigated with wastewater, and the incidence of some of the pathogens in wastewaters. Because many areas are now utilizing wastewater for a variety of purposes from potable water to landscape irrigation, proposed regulations governing its use are discussed.
Article
Three outbreaks of waterborne disease have been attributed to Cryptosporidium - two linked to drinking water and a third to surface water - yet the risk of waterborne disease is unknown because many factors may contribute to transmission. Of 107 surface water samples collected in six western states, 77 were positive for the presence of Cryptosporidium oocysts. A high count was found in raw sewage (1,732 oocysts/L), whereas low counts were found in waters without waste discharges (0. 04 oocysts/L). Cryptosporidium has also been detected in drinking water. Little information is available, however, on oocyst survival in the environment or during sewage and drinking water treatment processes. It has been suggested that the epidemiology and transmission of Cryptosporidium are similar to Giardia. Based on environmental occurrence, the risk of Cryptosporidium transmission by the water route may be equal to or greater than that of Giardia.
Article
The preface indicates that this relatively brief book (eight chapters) is intended to serve as a general introductory text for medical, nursing, and public health students.The book provides cogent explanations and definitions of both environmental health and environmental epidemiology and outlines well both the host and environmental components. Each environmental cause of disease (infectious agents, chemicals, and radiation) is specifically discussed. In addition, sections deal with environmental issues, such as air pollution, occupation, and hazardous waste management, that cross all etiological agent categories. There are also sections dealing with selected environmental and occupational health laws. Water pollution is discussed generally in the chapters on infectious agents and chemicals. It is also acknowledged that injury is an important hazard in the general and occupational environment.There are only a few tables and figures, but they enhance the text well, adding to the reader's understanding. Likewise, the ten-page index is reasonably
Article
Reuse of domestic sewage effluents in Arizona requires that certain microbiological standards be met. The purpose of this project was to determine the effectiveness of rapid mixed media filtration in the removal of enteric viruses, fecal coliforms and roundworm eggs from sewage destined for reuse as irrigation water. Two surrogate viruses, the simian rotavirus SA-11, used in place of human rotavirus which is pathogenic to man, and f2 coliphage, known to adsorb poorly to surfaces, were used to evaluate filter performance. No significant removal of coliphages occurred by the filters. Addition of ferric chloride and anionic polymer did not enhance virus removal. When small amounts of alum and polymer were added, removal of colliphage increased to 37–40%. Average removal of rotavirus ranged from 21 to 27% after addition of alum and polymer. Mixed media filtration effectively reduced coliform numbers. The removal of Ascaris ova by filtration was essentially complete.
Article
Methods are described for the efficient concentration of an enterovirus from large volumes of tap water, sewage, and seawater. Virus in acidified water (pH 3.5) in the presence of aluminum chloride was adsorbed to a 10-inch (ca. 25.4 cm) fiberglass depth cartridge and a 10-inch pleated epoxy-fiberglass filter in a series at flow rates of up to 37.8 liters (10 gallons) per min. Adsorbed viruses were eluted from the filters with glycine buffer (pH 10.5 to 11.5), and the eluate was reconcentrated by using a combination of aluminum flocculation followed by hydroextraction. With this procedure, poliovirus in large volumes of tap water, seawater, and sewage could be concentrated with an average efficiency of 52, 53, and 50%, respectively. It was demonstrated that this method is capable of detecting surface solid-associated viruses originating from sewage treatment plants. No difference in virus recovery between laboratory batch studies and a set-up with acid-salt injection was found. This unified scheme for the concentration of viruses has many advantages over previously described systems. These include: high operating flow rates, low weight and small size, effectiveness with a variety of waters with widely varying qualities, and filters with a high resistance to clogging.
Article
The levels of cytopathic enteroviruses at two wastewater-treatment works were monitored over a period of 9 months. The maximum level of virus at works 1 was 72500 p.f.u. l-1 and at works 2, 57500 p.f.u. l-1. Examination of process efficiency showed an overall reduction of 63% for works 1 and 26% for works 2 when used without lagooning. When lagooning was employed at the second works, virus reduction was 97%. Individual treatment processes showed poor reduction of virus levels. Sedimentation and rapid sand filtration had no significant effect on levels whilst both percolating filtration and activated sludge showed some reduction. Only lagooning resulted in substantial reductions of virus levels.
Article
Haas, C. N. (Illinois institute of Technology, Chicago, IL 60616). Estimation of risk due to low doses of microorganisms: a comparison of alternative methodologies. Am J Epidemiol 1983; 118: 573–82. The log-normal, or log-probit, simple exponential and beta distributed effectiveness models were evaluated for their ability to describe experimental dose-response data for human exposure to waterborne bacteria and viruses. Each of the models was capable of describing at least some of the available data; however, the beta-distributed model appeared to be the most widely applicable. When used to extrapolate to extremely low exposure levels, divergent predictions are obtained for each of the three models. On the basis of this analysis, It is impossible to rule out the hypothesis that a single microorganism when ingested has the potential of inducing infection or disease.
Monitoring of water and wastewater for Giardia Advances in Water Analysis and Treatment Water Quality Technology Conference
  • J L Sykora
  • S J States
  • W D Bancroft
  • S N Boutrous
  • M A Shapino
  • L F Conley
Sykora, J.L., states, S.J., Bancroft, W.D., Boutrous, S.N., Shapino, M.A., and Conley, L.F. (1986). Monitoring of water and wastewater for Giardia. In: Advances in Water Analysis and Treatment Water Quality Technology Conference, Nov. 16-20, Portland, OR, AWWA, Denver, CO, pp. 1043-1054. 18. U.S. EPA. (1984). Manual of Methods for virology. U.S. Environmental Protection Agency, Cincinnati, OH.
Water reuse practices in the United States Reduction of naturally occurring enteroviruses by wastewater treatment processes
  • K J Miller
Miller, K.J. Water reuse practices in the United States. In Proc. Int. Conv. Australian Water and Wastewater Assoc., Melbourne, Australia, April 28 to May 3, 1985. 11. Morris, R. (1984). Reduction of naturally occurring enteroviruses by wastewater treatment processes. �. HVg. 2A:97-103.
WAter Quality standards of Wastewater Reuse
  • B Rose
B. ROSE and C. P. GERBA REFERENCES 1. Arizona., (1984). WAter Quality standards of Wastewater Reuse. Arizona Department of State, Phoenix, Arizona.
WAter Quality standards of Wastewater Reuse. Arizona Department of State
  • Arizona
Arizona., (1984). WAter Quality standards of Wastewater Reuse. Arizona Department of State, Phoenix, Arizona.
Water reuse practices in the United States
  • K J Miller
Miller, K.J. Water reuse practices in the United States. In Proc. Int. Conv. Australian Water and Wastewater Assoc., Melbourne, Australia, April 28 to May 3, 1985.
  • J B Rose
  • H Darbin
  • C P Gerba
Rose, J.B., Darbin, H., and Gerba, C.P. (1988). Correlations of the Protozoa, Cryptosporidium and Giardia with water quality variables in a watershed. water and Science Technology, � 11/12:271-276.
Monitoring of water and wastewater for Giardia
  • J L Sykora
  • S J States
  • W D Bancroft
  • S N Boutrous
  • M A Shapino
  • L F Conley
Sykora, J.L., states, S.J., Bancroft, W.D., Boutrous, S.N., Shapino, M.A., and Conley, L.F. (1986). Monitoring of water and wastewater for Giardia. In: Advances in Water Analysis and Treatment Water Quality Technology Conference, Nov. 16-20, Portland, OR, AWWA, Denver, CO, pp. 1043-1054.
Manual of Methods for virology
  • U S Epa
U.S. EPA. (1984). Manual of Methods for virology. U.S. Environmental Protection Agency, Cincinnati, OH.