Ml Of Sewage Research Articles

Hepatitis E Virus (Genotype 3) in Slurry Samples from Swine Farming Activities in Italy.

Hepatitis E virus (HEV) is an emergent causative agent of acute hepatitis, transmitted by fecal-oral route. Infection with HEV is a global cause for morbidity and mortality throughout the world: it mainly causes large outbreaks in endemic areas and sporadic autochthonous cases in industrialized countries where HEV infections seem to be an emergent zoonotic disease. Infection of porcine livestock and its relationship with the human cases have been demonstrated. The present study describes an investigation on the prevalence and diversity of HEV in pig slurry in Italy. Slurry samples (24) were collected from ten farms located in North Italy during 2015 and analyzed for HEV, using four broad-range nested PCR assays targeting ORF1 (MTase), ORF2 (capsid) genes, and ORF2/3 regions. Overall, 18 samples (75%) were positive for HEV RNA, and characterized as genotype 3. Nine samples could be subtyped by ORF2 sequencing: Eight belonged to subtype 3f, while one sequence could not be characterized by blast analysis and phylogenetic analysis and may actually represent a new subtype. Furthermore, similarity of 99% was found between 3f Italian HEV sequences of human and swine origins. Real-Time PCR assay was also performed, in order to obtain quantitative data on positive samples. Two swine slurry samples were positive, containing 600 and 1000 UI per mL of sewage. The results of this study show that HEV strains belonging to zoonotic genotype 3 are widely present in swine excreta, and have high degree of identity with strains detected in autochthonous HEV cases. Improving swine farming operations safety and increasing operators' awareness of the zoonotic potential connected with the handling of swine effluents turn out to be key points in order to reduce the environmental and sanitary problem represented by the possible dissemination of HEV to water bodies.

Performance evaluation of the household ultraviolet water purifier

In this study water disinfection capability of three household ultraviolet water purifiers was studied. The first two purifiers were composed of three housings, namely, for polypropylene yarn cartridge, for granular activated carbon cartridge and for 4-pin ultraviolet lamp. The third purifier was a horizontal water flow system containing a bi-pin ultraviolet lamp labeled as UV water Sterilizer. This study focused on the performance of the cylindrical UV disinfection reactor. Eleven ultraviolet lamps were labeled and placed in the UV sets turn wise. 100 ml of water samples collected from various sites were studied for coliform colonies growth before UV irradiation and after the process. To study the affect of the biodose on the efficiency of UV lamps, one/two ml of sewage was injected in 25 liters of tube well water. The performance of various lamps was studied after 24 hours incubation. The lamps were efficient for low bio-dose but none of the lamps was found efficient against high-bio-dose. The public health services require that UV lamp should have a minimum UV dose of 16,000-µw sec./cm2. Spectroscopic studies revealed that all the UV lamps irradiate a beam of 253.7 nm,. These lamps differed in the emitted UV dose and the arc length only. Quartz sleeves surround UV lamps in the disinfection reactor. Four quartz sleeves were spectroscopically studied for UV transmittance. It was found that the green sleeve was pure silicate glass having zero percent transmittance for UVC, while the other three were good quality quartz sleeves. The hydraulic contact time of water film with UV lamp, and its optimum length was calculated from the analysis. As UV lamp of the optimum length and UV dose was not available, in order to achieve the required results the stainless steel jacket surrounding the sleeved lamp was replaced by a highly UV reflecting metallic jacket, or UV photo reflector. The improved design produced encouraging results.

A real‐time polymerase chain reaction assay for quantitative detection of the human‐specific enterococci surface protein marker in sewage and environmental waters

A real-time polymerase chain reaction (PCR) assay using SYBR Green I dye was developed to quantify the Enterococcus faecium enterococci surface protein (esp) marker in sewage (n = 16) and environmental waters (n = 16). The concentration of culturable enterococci in raw sewage samples ranged between 1.3 x 10(5) and 5.6 x 10(5) colony-forming units (cfu) per 100 ml. The real-time PCR detected 9.8 x 10(3)-3.8 x 10(4) gene copies of the esp marker per 100 ml of sewage. However, the concentration of culturable enterococci and the esp marker in secondary effluent was two orders of magnitude lower than raw sewage. Surface water samples were collected from a non-sewered catchment after storm events and the real-time PCR was applied to quantify the esp marker. Of the 16 samples tested, 6 (38%) were PCR-positive and the concentration of the esp marker ranged between 1.1 x 10(2) and 5.3 x 10(2) gene copies per 100 ml of water samples. The newly developed real-time PCR method was successfully used to quantify the esp marker in samples collected from sewage and environmental waters. The presence of the esp marker in water samples immediately after storm events not only indicated human faecal pollution but also provided evidence of the degree of human faecal pollution. To our knowledge, this is the first study that reports the use of a real-time PCR assay to quantify the esp marker in sewage and surface waters. Such study would provide valuable information for managers for the improved management of water quality.

Assessing the presence of BSE and scrapie in slaughterhouse wastewater

This paper describes a procedure for evaluating the presence and the stability of the proteinase K-resistant form of the prion protein (PrP(res)) in slaughterhouse wastewater. Wastewater samples were spiked with either scrapie or bovine spongiform encephalopathy agents and PrP(res) was concentrated and detected by western blotting. The detection limit was estimated to be 2-4 microg of either scrapie or BSE-infected brain tissue in 15 ml of sewage. Wastewater samples from three abattoirs were analysed, two of which had processed BSE-infected animals. No PrP(res) was detected. The effect of sewage on the inoculum and the persistence of transmissible spongiform encephalopathy agents in wastewater were also considered. The results of the assay suggest that wastewaters from abattoirs where one positive BSE case has been identified would contain titres lower than 0.6-26 x 10(-4) cattle oral ID(50) per litre resulting from specified risk material tissue contamination. Moreover, the effect of abattoir wastewaters is to reduce the persistence of PrP(res). The assay may be a useful tool for risk assessment studies and for reducing the potential risk of contamination with BSE via sewage sludge fertilizer procedures.

Lagoon Effluent Treatment Using Grass Filtration

The Western Treatment Plant (WTP) is one of the largest treatment plants in Australia treating more than 500 ML of sewage per day, discharging treated effluent to Port Phillip Bay in Victoria, Australia. The Port Phillip Bay Environmental Study (1992–1996) concluded that there was a need to reduce nitrogen loads from WTP to lower the risk of eutrophication, especially during winter when grass filtration was in operation. Therefore, in 1997, Melbourne Water initiated a pilot study to investigate the effectiveness of grass filtration for polishing wastewater that had received prior lagoon treatment. The study involved field monitoring of seven trial grass filtration bays at the WTP for hydraulic and water quality data from mid-May to early-October 1997. The results of the pilot study revealed that the removal rates of these nutrients were higher during the first half of the trials than during the second half. The results also showed that the removal rates of nutrients were inversely proportional to the hydraulic loading rates of the bays. A hydraulic loading rate of 40 mm/d was found to be optimal in this pilot study for achieving a balance between wastewater throughput and nutrient removal.

Abundance in sewage of bacteriophages that infect Escherichia coli O157:H7 and that carry the Shiga toxin 2 gene.

Shiga toxin-converting bacteriophages are involved in the pathogenicity of some enteric bacteria, such as Escherichia coli O157:H7, but data on the occurrence and distribution of such phages as free particles in nature were not available. An experimental approach has been developed to detect the presence of the Shiga toxin 2 (Stx 2)-encoding bacteriophages in sewage. The Stx 2 gene was amplified by PCR from phages concentrated from 10-ml samples of sewage. Moreover, the phages carrying the Stx 2 gene were detected in supernatants from bacteriophage enrichment cultures by using an Stx 2-negative E. coli O157:H7 strain infected with phages purified from volumes of sewage as small as 0.02 ml. Additionally, the A subunit of Stx 2 was detected in the supernatants of the bacteriophage enrichment cultures, which also showed cytotoxic activity for Vero cells. By enrichment of phages concentrated from different volumes of sewage and applying the most-probable-number technique, it was estimated that the number of phages infectious for E. coli O157:H7 and carrying the Stx 2 gene was in the range of 1 to 10 per ml of sewage from two different origins. These values were approximately 1% of all phages infecting E. coli O157:H7.

Explanations for the acclimation period preceding the mineralization of organic chemicals in aquatic environments.

A study was conducted of possible reasons for acclimation of microbial communities to the mineralization of organic compounds in lake water and sewage. The acclimation period for the mineralization of 2 ng of p-nitrophenol (PNP) or 2,4-dichlorophenoxyacetic acid per ml of sewage was eliminated when the sewage was incubated for 9 or 16 days, respectively, with no added substrate. The acclimation period for the mineralization of 2 ng but not 200 ng or 2 micrograms of PNP per ml was eliminated when the compound was added to lake water that had been first incubated in the laboratory. Mineralization of PNP by Flavobacterium sp. was detected within 7 h at concentrations of 20 ng/ml to 2 micrograms/ml but only after 25 h at 2 ng/ml. PNP-utilizing organisms began to multiply logarithmically after 1 day in lake water amended with 2 micrograms of PNP per ml, but substrate disappearance was only detected at 8 days, at which time the numbers were approaching 10(5) cells per ml. The addition of inorganic nutrients reduced the length of the acclimation period from 6 to 3 days in sewage and from 6 days to 1 day in lake water. The prior degradation of natural organic materials in the sewage and lake water had no effect on the acclimation period for the mineralization of PNP, and naturally occurring inhibitors that might delay the mineralization were not present. The length of the acclimation phase for the mineralization of 2 ng of PNP per ml was shortened when the protozoa in sewage were suppressed by eucaryotic inhibitors, but it was unaffected or increased if the inhibitors were added to lake water.(ABSTRACT TRUNCATED AT 250 WORDS)

Two approaches to modeling kinetics of biodegradation by growing cells and application of a two-compartment model for mineralization kinetics in sewage.

The patterns of microbial mineralization of 0.3 to 30 ng of glucose, benzoate, and phenol per ml of sewage collected in late fall and winter were analyzed with the integrated Monod equation and a model in which growth of active organisms occurs at the expense of organic compounds other than the test substrate. Either model could be closely fit by nonlinear regression to the data from individual tests with one concentration of substrate added to one dilution of sewage. However, neither model accounted satisfactorily for differences in patterns of mineralization resulting from differences in substrate concentration and cell density between different tests. It is suggested that both the added substrates and other organics present in sewage contributed to the growth of the active organisms. The mineralization of glucose in sewage collected in summer was better described by a two-compartment model than by any other model tested.

Models for mineralization kinetics with the variables of substrate concentration and population density.

The rates of mineralization of [14C]benzoate by an induced population of Pseudomonas sp. were measured at initial substrate concentrations ranging from 10 ng/ml to 100 micrograms/ml. Plots of the radioactivity remaining in the culture were fit by nonlinear regression to six kinetic models derived from the Monod equation. These models incorporate only the variables of substrate concentration and cell density. Plots of the mineralization kinetics in cultures containing low, intermediate, and high initial substrate concentrations were well fit by first-order, integrated Monod, and logarithmic kinetics, respectively. Parameters such as maximum specific growth rate, half-saturation constant, and initial population density divided by yield agreed between cultures to within a factor of 3.4. Benzoate mineralization by microorganisms in acclimated sewage was shown to fit logistic (sigmoidal), Monod, and logarithmic kinetics when the compound was added at initial concentrations of 0.1, 1.0, and 10 micrograms/ml, respectively. The mineralization of 10 micrograms of benzoate per ml in sewage also followed logarithmic kinetics in the absence of protozoa. It is concluded that much of the diversity in shapes of mineralization curves is a result of the interactions of substrate concentration and population density. Nonlinear regression with models incorporating these variables is a valuable means for analysis of microbial mineralization kinetics.

Fate in model ecosystems of microbial species of potential use in genetic engineering.

The changes in populations of Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Klebsiella pneumoniae, Agrobacterium tumefaciens, Rhizobium meliloti, and Saccharomyces cerevisiae were measured after their introduction into samples of sewage, lake water, and soil. Enumeration of small populations was possible because the strains used were resistant to antibiotics in concentrations and combinations such that few species native to these ecosystems were able to grow on agar containing the inhibitors. Fewer than 2 cells per ml of sewage or lake water and 25 cells per g of soil could be detected. A. tumefaciens and R. meliloti persisted in significant numbers with little decline, but S. aureus, K. pneumoniae, S. typhimurium, S. cerevisiae, and vegetative cells of B. subtilis failed to survive in samples of sewage and lake water. In sterile sewage, however, K. pneumoniae, B. subtilis, S. typhimurium, A. tumefaciens, and R. meliloti grew; S. cerevisiae populations were maintained at the levels used for inoculation; and S. aureus died rapidly. In sterile lake water, the population of S. aureus and K. pneumoniae and the number of vegetative cells of B. subtilis declined rapidly, R. meliloti grew, and the other species maintained significant numbers with little or a slow decline. The populations of S. aureus, K. pneumoniae, A. tumefaciens, B. subtilis, and S. typhimurium declined in soil, but the first four species grew in sterile soil. It is suggested that some species persist in environments in which they are not indigenous because they tolerate abiotic stresses, do not lose viability readily when starved, and coexist with antagonists. The species that fails to survive need only be affected by one of these factors.