Yossi Manor

Poliovirus distribution in the soil-plant system under reuse of secondary wastewater

Abstract Treated domestic wastewater is a source of water utilized for a variety of purposes. Outdoor experiments were conducted to examine poliovirus penetration into tomato plants under subsurface drip irrigation with secondary level treated domestic wastewater. According to the results, high virus content in the applied wastewater resulted in a limited penetration into the plant via the roots. No virus contamination was found in the leaves of plants irrigated with wastewater spiked with viruses, while a limited amount of virus contamination was detected in leaves of plants irrigated with tap water enriched with poliovirus.

Ecologically friendly wastewater disinfection techniques

Abstract The toxicity of the by-products found in water disinfected by chlorination methods prompted the regulatory agencies to insist on the use of alternative, ecologically friendly methods. This paper presents new disinfection techniques developed in our laboratory, which use sunlight or artificial UV radiation to promote photochemical disinfection processes. The sunlight was either used as global irradiation or concentrated by mirrors via an intermediary photosensitizer dissolved in water. Under these conditions the sunlight produces oxidative species in water which kill the microorganisms and oxidize organic materials. The disinfection efficiency of these methods has been proven in two experimental pilot plants operating in a continuous process with outputs of 50 and 0.15 m 3 h −1 , and retention times of 35 min and 3 s, respectively. The former process is economically competitive and is ready for practical use, especially in countries with high solar radiation flux densities. Data about a potential industrial application of concentrated solar radiation for detoxification of industrial wastewater polluted by a pesticide (bromacil) are presented. A new technique was used for UV (254 nm) water disinfection; it employs custom-designed elliptical UV reflectors which concentrate the radiation on a UV-transparent pipe through which the wastewater flows. The 5 m 3 h −1 laboratory installation provided efficient disinfection of wastewater with turbidities up to 20 NTU. For large UV water disinfection plants (> 100 m 3 h −1 ), a new design is proposed, which could replace the present gravitational systems.

Intensified environmental surveillance supporting the response to wild poliovirus type 1 silent circulation in Israel, 2013

An emergency response was triggered by recovery of wild poliovirus type 1 (WPV1) of the South Asia (SOAS) lineage from sewage in southern Israel in April 2013 during routine environmental surveillance. Public health risk assessment necessitated intensification of environmental surveillance in order to facilitate countrywide monitoring of WPV1-SOAS circulation. This involved increasing sampling frequency and broadening the geographical area, for better coverage of the population at risk, as well as modifying sewage testing algorithms to accommodate a newly developed WPV1-SOAS-specific quantitative real-time RT-PCR assay for screening of RNA extracted directly from sewage concentrates, in addition to standard virus isolation. Intensified surveillance in 74 sites across Israel between 1 February and 31 August 2013 documented a sustained high viral load of WPV1-SOAS in sewage samples from six Bedouin settlements and two cities with Jewish and Arab populations in the South district. Lower viral loads and intermittent detection were documented in sampling sites representing 14 mixed communities in three of the five health districts in central and northern Israel. Environmental surveillance plays a fundamental role in routine monitoring of WPV circulation in polio-free countries. The rapid assay specific for the circulating strain facilitated implementation of intensified surveillance and informed the public health response and decision-making.

Photochemical disinfection of effluents—pilot plant studies

Abstract A new method of photochemical disinfection of domestic effluents for crop irrigation was investigated in a pilot plant. It uses sunlight as the energy source, the oxygen dissolved in water (DO) as the oxidizing agent and methylene blue (MB) as an intermediary for the absorption and transfer of the sunlight energy (red range) to activate DO and/or to destabilize the organic matter. The pilot plant consists of a series of six identical reactors, each 488 cm in length and 35 cm in height. The reactors were constructed from welded galvanized steel plates having a trapezoidal cross-section. A height differential of about 10 cm between two adjacent reactors ensured free overflow of the treated effluent through the pilot plant. Hydraulic experiments carried out with different effluent flow rates led to the construction and mounting of hydraulic devices which improved the relative residence time of the effluent in the reactors and decreased the hydraulic short-circuiting of the flowing effluent. The lack of DO in the supplied effluent was overcome by using a new method of adding O 2 (from 0.1–0.5 to 4–6 mg l −1 ), by introducing the effluent under pressure. The best microbiological results were obtained in disinfection experiments done under the following conditions: pH, 8.8–8.9 (CaO 80–90 g m −3 ); DO, 4.5–5.5 mg l −1 ; MB, 0.85–0.90 g m −3 ; effluent flow rate, 10 m 3 h −1 ; effluent depth, 20 cm; average sunlight exposure, 58 min; and sunlight intensities, 700–2000 μE −2 s −1 . The decrease in the microorganism count was (logs): coliforms. 3.0 ± 0.5; fecal coliforms, 3.1 ± 0.4; enterococci, 3.76 ± 0.4; and polioviruses, 1.8 ± 0.4. These results were reproducible and could be improved by technical amelioration of the pilot plant.

Sunlight disinfection of domestic effluents for agricultural use

Abstract The photochemical method of disinfecting domestic effluents planned for use as irrigation water for edible crops was developed further, reaching a stage at which it can be used on an industrial scale. This disinfection method uses sunlight as the activation energy source; the oxygen dissolved in water (DO) as the oxidizing agent; and a dye-sensitizer (methylene blue) as an intermediary for the absorption and transfer of the sunlight energy to activate DO and/or to destabilize the organic matter molecules and the microorganisms as the oxidation target. The study was carried out in an experimental pilot-scale plant, capable of treating up to 50 m3/h of effluent supplied by an activated sludge sewage treatment plant located in the Tel-Aviv area. The plant consists of a series of 10 identical photoreactors (6 × 2 × 0.3 m3), installed in series on an unpaved road with a 2% slope which ensures free overflow of the treated effluent through the pilot plant. Preceding the photoreactors there is a mixing reactor (2 × 2 × 1 m3) which supplies the effluent with DO (> 6 g O2/m3), MB (0.7 ± 0.1 g/m3) and calcium hydroxide (33 ± 3 g/m3) for pH correction (8.7–8.9). Operating the pilot plant at an effluent flow rate of 33 ± 3 m3/h (effluent detention time: 35 ± 2 min), sunlight intensities 700–2600 μEm−2 s−1, the following decreases in microbial counts were observed (log counts): coliforms −3.2 ± 0.3; fecal coli −3.12 ± 0.2; fecal streptococci −3.9 ± 0.3; poliovirus −1.9 ± 0.25. The treated effluents did not show regrowth of these microorganisms during 7 days storage in photoreactors, and did not form an impermeable crust when infiltrated into sandy soils. The effluent disinfection cost in a “sunlight disinfection plant” producing 200 m3 disinfected effluent per hour is estimated to be U.S.

Development and validation of a real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay for investigation of wild poliovirus type 1-South Asian (SOAS) strain reintroduced into Israel, 2013 to 2014.

3.95 per 100 m3.

Membrane technology for sustainable treated wastewater reuse: agricultural, environmental and hydrological considerations

In February 2013, wild poliovirus type 1 (WPV1) was reintroduced into southern Israel and resulted in continuous silent circulation in the highly immune population. As a part of the public health emergency response, a novel real time quantitative reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed, to allow for the sensitive and specific detection of the circulatingWPV1-South Asian (SOAS) strain. Specific primers and probes derived from the VP-1 region were designed, based on sequenced sewage isolates, and used to simultaneously amplify this WPV1-SOAS sequence together with bacteriophage MS-2 as internal control. High titre WPV1-SOAS stock virus was used for assay optimisation and 50 processed sewage samples collected from southern Israel and tested by reference culture based methods were used for analytical validation of the assay’s performance. The limit of detection of the multiplex qRT-PCR (SOAS/MS-2) assay was 0.1 plaque-forming unit (pfu)/reaction (20 pfu/mL) for WPV1-SOAS RNA with 100% sensitivity, specificity, positive and negative predictive values when compared to the culture based method. The turnaround time was rapid, providing results for environmental samples within 24 to 48 hours from completion of sewage processing, instead of five to seven days by culture-based analysis. Direct sewage testing by qRT-PCR assay proved to be a useful tool for rapid detection and environmental surveillance of WPV1-SOAS circulating strain during emergency response. Application of the approach for detection of WPV1-SOAS in stool samples obtained during acute flaccid paralysis (AFP) surveillance or field surveys should be further evaluated.

Estimation of polio infection prevalence from environmental surveillance data

Field experiments were conducted in agricultural fields in which secondary wastewater of the City of Arad (Israel) is reused for irrigation. For sustainable agricultural production and safe groundwater recharge the secondary effluent is further polished by a combined two-stage membrane pilot system. The pilot membrane system consists of two main in row stages: Ultrafiltration (UF) and Reverse Osmosis (RO). The UF stage is efficient in the removal of the pathogens and suspended organic matter while the successive RO stage provides safe removal of the dissolved solids (salinity). Effluents of various qualities were applied for agricultural irrigation along with continuous monitoring of the membrane system performance. Best agricultural yields were obtained when applying effluent having minimal content of dissolved solids (after the RO stage) as compared with secondary effluent without any further treatment and extended storage. In regions with shallow groundwater reduced soil salinity in the upper productive layers, maintained by extra membrane treatment, will guarantee minimal dissolved solids migration to the aquifers and minimize salinisation processes.

Hepatitis E Virus Genotype 3 in Sewage and Genotype 1 in Acute Hepatitis Cases, Israel

Close monitoring of virus shed into sewage systems allows quantitative surveillance of a polio outbreak. Keeping an eye on polio As the eyes are a mirror of the soul, a city’s sewage is a reflection of its people’s health. Berchenko et al. take advantage of a natural experiment in southern Israel to quantify this relationship for polio. By measuring virus shed into sewage waste in cities in which a known number of people received a live polio vaccine, the authors created tools that can be used to monitor polio incidence in other cities. Thus, virus levels in sewage waste can give an early warning of the reappearance of viral disease or verify its absence. A major obstacle to eradicating polio is that poliovirus from endemic countries can be reintroduced to polio-free countries. Environmental surveillance (ES) can detect poliovirus from sewage or wastewaters samples, even in the absence of patients with paralysis. ES is underused, in part because its sensitivity is unknown. We used two unique data sets collected during a natural experiment provided by the 2013 polio outbreak in Israel: ES data from different locations and records of supplemental immunization with the live vaccine. Data from the intersecting population between the two data sets (covering more than 63,000 people) yielded a dose-dependent relationship between the number of poliovirus shedders and the amount of poliovirus in sewage. Using a mixed-effects linear regression analysis of these data, we developed several quantitative tools, such as (i) ascertainment of the number of infected individuals from ES data for application during future epidemics elsewhere, (ii) evaluation of the sensitivity of ES, and (iii) determination of the confidence level of the termination of poliovirus circulation after an outbreak. These results will be valuable in monitoring future outbreaks with ES, and this approach could be used to certify poliovirus elimination or to validate the need for more containment efforts.

Molecular Characterization of Polio from Environmental Samples: ISSP, The Israeli Sewage Surveillance Protocol

Hepatitis E virus (HEV) is an emerging infectious agent in developed countries. HEV genotypes 1 (G1) and 3 (G3) have been identified in environmental and clinical samples in Europe. In Israel, the overall prevalence of anti-HEV IgG antibodies was found to be 10.6%; however, reports of HEV infection are scarce. In this study, the presence of HEV in Israel was investigated using 169 sewage samples from 32 treatment facilities and 49 samples from acute hepatitis patients, all collected between 2013 and 2015. Fourteen sewage samples, from Haifa (11/18 samples), Tel Aviv (2/29 samples), and Beer Sheva (1/17 samples), regions with good sanitary conditions and middle-high socioeconomic populations, were HEV positive. Among the patient samples, 6.1% (3/49) were HEV positive, all returning travelers from India. Genotype analysis revealed G1 HEV in patients and G3 HEV sequences in sewage. Evidence that HEV could be establishing itself in our region may justify more active surveillance to monitor its spread.