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In the present study, three low-cost filter aggregate materials were tested and compared for organic matter and fecal coliform (FC) removal at the laboratory scale. Setups were subjected to synthetic wastewater at two hydraulic loading rates (HLR), i.e. 4 cm/day and 40 cm/day. The hydraulic retention time (HRT) at the two HLRs varied from 4 days to 12 h, respectively. The result obtained shows that the biochemical oxygen demand (BOD5) removal efficiency of aggregate materials decreased with the increase in HLR. Both at high and low HLR, the terracotta aggregate material exhibited maximum BOD5 loading removal and without significant difference for the case of FC removal efficiency for all the three aggregate materials. At higher HLR, cell debris and biofilm loss from the aggregate material contributed to the chemical oxygen demand (COD) levels in the treated water. The terracotta aggregate material provided best organic matter removal at both HLRs. The study demonstrates the potential of incorporating inexpensive and readily available local materials into decentralized, frugal green infrastructure interventions capable of lowering the quantum of harmful biological contaminants in open storm water channels in rapidly urbanizing cities of developing countries, and that the terracotta aggregate material provided best organic removal at both HLRs. [ABSTRACT FROM AUTHOR]

Coastal water quality is deteriorating worldwide. Water quality monitoring is therefore essential for public health risk evaluation and the management of water bodies. This study investigated the feasibility of using bacteriophages of Enterococcus faecalis as sewage-specific faecal indicators, together with physicochemical (dissolved oxygen, pH, temperature and total suspended solids) and biological parameters, to assess coastal water quality using multivariate analysis incorporating non-detects. The principal component and cluster analyses demonstrated that coastal water quality was mostly influenced by biological parameters, including Escherichia coli and total coliforms, which were found in all 31 sampling sites, and enterococci, which was found in all but two sampling sites. The enterococcal bacteriophages AIM06 and SR14 were detected in 17 and 18 samples at concentrations up to 1,815 and 2,790 PFU/100 mL, respectively. Both bacteriophages co-presented in approximately 80% of phage-positive samples, and the concentrations at each site were not significantly different. Overall, either bacteriophage could be used to differentiate high- and low-level coastal water pollution, as grouped by cluster analysis. This study is the first to investigate the suitability of sewage-specific bacteriophages of E. faecalis for monitoring coastal water quality and emphasises the importance of a multivariate analysis with non-detects to facilitate coastal water quality monitoring and management. [ABSTRACT FROM AUTHOR]

This study examined the individual and combined effects of potassium ferrate(VI) additions and freezethaw conditioning for the treatment and dewatering of wastewater sludge in cold climates, with particular focus on the inactivation of fecal coliforms and oxidation of estrogens, androgens, and progestogens. The first phase of the study evaluated the effects of potassium ferrate(VI) pre-treatment followed by freeze-thaw at -20 °C using a low (0.5 g/L) and high (5.0 g/L) dose of potassium ferrate(VI). The results showed that pre-treatment of anaerobically digested sludge with 5 g/L of potassium ferrate(VI) reduced the concentration of fecal coliforms in the sludge cake to below 100 MPN/g DS. The second phase evaluated the ability of ferrate(VI) to oxidise selected hormones in sludge. Anaerobically digested sludge samples were spiked with 10 different hormones: estrone (E1), 17α-estradiol, 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), equilin, mestranol, testosterone, norethindrone and norgestrel in two groups of low (3-75 ng/mL) and high (12-300 ng/L) concentration ranges of hormones. The samples were treated with either 0.5 or 1.0 g/L of potassium ferrate(VI), and hormone concentrations were measured again after treatment. Potassium ferrate(VI) additions as low as 1.0 g/L reduced the concentration of estrogens in sludge. Potassium ferrate(VI) additions of 0.5 and 1.0 g/L were less effective at reducing the concentrations of androgens and progestogens. Increasing ferrate(VI) dose would likely result in more substantial decreases in the concentrations of fecal coliforms and hormones. The results of this study indicate that the combined use of freeze-thaw and ferrate(VI) has the potential to provide a complete sludge treatment solution in cold regions. [ABSTRACT FROM AUTHOR]

Environmental issues have a worldwide impact on water bodies, including the Danube Delta, the largest European wetland. The Water Framework Directive (2000/60/EC) implementation operates toward solving environmental issues from European and national level. As a consequence, the water quality and the biocenosis structure was altered, especially the composition of the macro invertebrate community which is closely related to habitat and substrate heterogeneity. This study aims to assess the ecological status of Southern Branch of the Danube Delta, Saint Gheorghe, using benthic fauna and a computational method as an alternative for monitoring the water quality in real time. The analysis of spatial and temporal variability of unicriterial and multicriterial indices were used to assess the current status of aquatic systems. In addition, chemical status was characterized. Coliform bacteria and several chemical parameters were used to feed machine-learning (ML) algorithms to simulate a real-time classification method. Overall, the assessment of the water bodies indicated a moderate ecological status based on the biological quality elements or a good ecological status based on chemical and ML algorithms criteria. [ABSTRACT FROM AUTHOR]

Survey of schools of different education levels (primary, intermediate and secondary) in Kuwait showed an average greywater generation rate of 7.3 L/p/d and varied in the range of 2.9-16 l/p/d, reflecting the school level of education (i.e. student age). The highest rates were observed for primary schools while the lowest rates were observed in secondary schools where students are more mature and use the water more wisely. The greywater characteristics indicated waste with low chemical oxygen demand (COD) and 5-day biochemical oxygen demand (BOD5) values but relatively high solids, conductivity, and sodium content due to excessive use of hand soap. Total coliform values ranged between 89 and 352 most probable number (MPN)/mL with an average of 196 MPN/mL while no fecal coliform values were detected. Greywater collected from schools is classified as light greywater and contains much lower levels of organic matter and nutrients compared to residential greywater and domestic wastewater. It is suitable for non-potable reuse after minimal treatment since microbial contamination may pose a serious threat to health if greywater comes into contact with humans. It also provides a good opportunity for reuse in toilet flushing since it can be easily collected from wash sinks and fountains, as major sources, and recycled. [ABSTRACT FROM AUTHOR]

An important tool in environmental management projects and studies due to the complexity of environmental systems, environmental modeling makes it possible to integrate many variables and processes, thereby providing a dynamic view of systems. In this study the bacteriological quality of the coastal waters of Fortaleza (a state capital in Northeastern Brazil) was modeled considering multiple contamination sources. Using the software SisBaHiA, the dispersion of thermotolerant coliforms and Escherichia coli from three sources of contamination (local rivers, storm drains and submarine outfall) was analyzed. The models took into account variations in bacterial decay due to solar radiation and other environmental factors. Fecal pollution discharged from rivers and storm drains is transported westward by coastal currents, contaminating strips of beach water to the left of each storm drain or river. Exception to this condition only occurs on beaches protected by the breakwater of the harbor, where counterclockwise vortexes reverse this behavior. The results of the models were consistent with field measurements taken during the dry and the rainy season. Our results show that the submarine outfall plume was over 2 km from the nearest beach. The storm drains and the Maceió stream are the main factors responsible for the poor water quality on the waterfront of Fortaleza. The depollution of these sources would generate considerable social, health and economic gains for the region. [ABSTRACT FROM AUTHOR]

Constructed wetland ecotechnologies (CWEs) are a promising solution to effectively treat domestic wastewater in developing countries at low cost. This paper reports the findings of the effectiveness of sand media amended with woody biochar and two plants species (Melaleuca quinquenervia and Cymbopogon citratus) in removing biological oxygen demand (BOD5), suspended solids and coliforms. The experimental design consisted of 21 vertical flow (VF) mesocosms. There were seven media treatments using sand amended with varying proportions of biochar. During the first 8 months, the mesocosms were loaded with secondary clarified wastewater (SCW) then septage. The influent had a 4-day hydraulic retention time. Samples were monitored for BOD5, total suspended solids (TSS), total volatile solids (TVS), total coliforms and faecal coliforms. In the first 8 months, there were no significant performance differences between media treatments in the outflow concentrations of BOD5, TSS and TVS. The significant differences occurred during the last 3 months; using septage with biochar additions performed better than pure sand. For coliforms, the significant differences occurred after 6 months. In conclusion, the addition of biochar was not effective for SCW. The VF mesocosms system proved to be more effective in removing BOD5, TSS, TVS and coliforms when septage was loaded into the media. [ABSTRACT FROM AUTHOR]

This study examined the performance of subsurface flow horizontal wetlands in total coliforms, faecal coliforms, enterococci and Salmonella removal from swine and domestic wastewaters. The effects of organic loading rate, contact time (CT) and the presence of aquatic macrophytes, Typha dominguensis and Typha latifolia, on treatment performance were evaluated. In general, chemical oxygen demand (COD) and total suspended solids (TSS) were reduced by 66 and 72% after 24 h and 75 and 84% after 48 h in domestic wastewaters, and 73 and 71% after 24 h and 72 and 78% after 48 h in swine wastewater. Total coliform and faecal coliform reductions of 70-83% and 65-78% were observed in the vegetated systems after 24 h of CT, while after 48 h, total coliform and faecal coliform reductions of 80-82% and 86-91% were noted. [ABSTRACT FROM AUTHOR]

Stabilization ponds are a highly appropriate system for treating sewage in small to medium size communities. However, sludge accumulation at the pond bottom occurs with the passage of time, reducing the net pond volume, which, in principle, could affect its performance. The objective of this paper is to compare the behaviour of two equal ponds in parallel treating the same flow of municipal wastewater from an upflow anaerobic sludge blanket reactor in Brazil. Each pond treated a population equivalent of around 125 inhabitants. One pond had approximately 40% of its net volume occupied by sludge after 11 years of operation, while the other pond had previously undergone complete desludging. The study covers the removal of biochemical oxygen demand (BOD), chemical oxygen demand (COD), suspended solids (SS), nitrogen fractions and coliforms. Owing to the presence of a sludge layer, the theoretical hydraulic retention time (HRT) was lower in the pond without sludge. For BOD, COD, SS and Escherichia coli there were no significant differences (Wilcoxon matched-pairs test) between both ponds. The pond without sludge had significantly better removal efficiencies in terms of total Kjeldahl nitrogen and ammonia-N. The sludge layer probably allowed the occurrence of removal mechanisms that compensated for the reduction caused in the HRT. [ABSTRACT FROM AUTHOR]

This study aimed to assess the quantity and quality of water in a surface flow constructed wetland in Australia's far north Queensland. Owing to tropical climate in the region, the wetland provided dual functions: retention of a treated wastewater for zero discharge during the dry season and tertiary treatment prior to discharge during the wet season. Rainfall data, permeability of wetland soil, evaporation, inflow and outflow were analysed in a water balance analysis; the results showed that based on a 72-year-average rainfall pattern, daily wastewater inflow of 85 m3/d is the maximum this wetland can cope with without breaching its discharge certificate. In water quality analysis, the K-C* model was used to predict changes of biochemical oxygen demand (BOD, suspended solids (SS), total nitrogen (TN), total phosphorus (TP) and faecal coliforms (FC) in the wetland. Model predictions were compared with field sampling results. It was found that the wetland was effective in removing FC (>99.9%), TN (70.7%) and TP (68.2%), for which the predictions by the K-C* model were consistent with field testing results. However, significant disparities between the predictions and testing results were found for BOD and SS. A revised K-C* equation was proposed to account for the internal generation of organics in constructed wetlands with a long retention time. [ABSTRACT FROM AUTHOR]

The purpose of this research was to study the disinfection of sanitary effluent from constructed wetlands, evaluating the oxidation of organic matter, the formation of formaldehyde, as well as the efficiency of total coliforms and Escherichia coli inactivation. A constant flow of ozone was applied to the batch system in 5 and 10mg.O3 L-1 doses with contact times of 5 and 10min. This study revealed that the average values of formaldehyde formation ranged between 259.00 and 379.00 μg L-1, which means that the values are within World Health Organization recommended values. The total coliforms and E. coli showed complete inactivation in almost all tests. The dose of ozone 5 mg.O3 L-1 and contact time of 5 min were sufficient for a significant reduction of the concentration levels of pathogens in constructed wetlands effluent with similar characteristics, thus allowing for its agricultural reuse. [ABSTRACT FROM AUTHOR]

Microbial contamination in surface waters has become a worldwide cause for concern. As efforts are made to reduce this contamination, monitoring is integral to documenting and evaluating water quality improvements. Autosamplers are beneficial in such monitoring efforts, as large data sets can be generated with minimized effort. The extent to which autosamplers can be utilized for microbial monitoring is largely unknown due to concerns over contamination. Strict sterilization regimes for components contacting the water being sampled are difficult, and sometimes logistically implausible, when utilizing autosamplers. Field experimentation showed contamination of fecal coliform in autosamplers to be more of a concern than that of Escherichia coli. Further study in a controlled laboratory environment suggested that tubing configuration has a significant effect on residual E. coli concentrations in sampler tubing. The amount of time that passed since the last sample was collected from a given sampler (antecedent dry weather period - DWP) tubing was also a significant factor. At a DWP of 7 days, little to no contamination was found. Thus, simple protocols such as providing positive drainage of tubing between sample events and programming samplers to include rinses will reduce concerns of contamination in autosamplers. [ABSTRACT FROM AUTHOR]

The paper is a review of previous research on secondary effluent disinfection by peracetic acid (PAA) integrated with new data about the effect of a preliminary flash-mixing step. The process was studied at bench and pilot scale to assess its performance for discharge in surface water and agricultural reuse (target microorganisms: Escherichia coli and faecal coliform bacteria). The purposes of the research were: (1) determining PAA decay and disinfection kinetics as a function of operating parameters, (2) evaluating PAA suitability as a disinfectant, (3) assessing long-term disinfection efficiency, (4) investigating disinfected effluent biological toxicity on some aquatic indicator organisms (Vibrio fischeri, Daphnia magna and Selenastrum capricornutum), (5) comparing PAA with conventional disinfectants (sodium hypochlorite, UV irradiation). PAA disinfection was capable of complying with Italian regulations on reuse (10 CFU/100 mL for E. coli) and was competitive with benchmarks. No regrowth phenomena were observed, as long as needed for agricultural reuse (29 h after disinfection), even at negligible concentrations of residual disinfectant. The toxic effect of PAA on the aquatic environment was due to the residual disinfectant in the water, rather than to chemical modification of the effluent. [ABSTRACT FROM AUTHOR]

Agave plants grow in semi-arid regions and are used for mescal production. However, agave fiber by-products are considered waste materials. Thus, we tested agave fiber as a filter media and biofilm material carrier for removing pollutants from municipal wastewater. Three laboratory-scale biofiltration reactors were used in two trials with five hydraulic loading rates (HLRs = 0.27, 0.54, 0.80, 1.07 and 1.34 m3 m-2 d-1 ). One series was conducted using mechanical aeration (0.62 m3 m-2 h-1 ). To prevent compaction, decreasing pressure and clogging of the filter media, 4, 8 and 12 internal divisions were evaluated in the biofilter column. After 17 months of continuous operation at an HLR of 0.80 m3 m-2 d-1 , the removal efficiencies of the aerated biofilters were 92.0% biochemical oxygen demand, 79.7% chemical oxygen demand, 98.0% helminth eggs, 99.9% fecal coliforms and 91.9% total suspended solids. Statistical analysis showed that the chosen operational parameters significantly influenced the removal efficiencies of the biofilters. The effluent quality obtained under these conditions complied with the Mexican and US EPA standards for agricultural irrigation and green spaces, except for coliforms, which is why the effluents must be disinfected. Thus, agave fiber is a favorable choice for use as a packing material in biofiltration processes. [ABSTRACT FROM AUTHOR]

In the literature, analytical models have been shown to be extremely useful for estimating the decay rates of coliform as fecal indicator microorganisms, providing reliable predictions of bathing conditions in coastal and continental waters. Although a number of different formulations have been developed in the literature, each one may only be suitable for specific environments, and no comparison between these methods has ever been carried out. In the present article, a comparative analysis of bacterial decay models, calculated by eight different formulations, was performed in coastal outfall plumes, considering identical environmental conditions of solar radiation, temperature and salinity. A statistical approach was applied to identify the differences in means and in behaviors of the results obtained in the various simulations. The results indicate good agreement between bacterial decay rates calculated with at least four methods that were considered more reliable, and at least one of the models was shown to be suitable for estimating bacterial decay rates under nighttime conditions, considering only the combined influences of temperature and salinity. Moreover, under daytime conditions, it provides consistent decay rates when compared with measurements taken in the field. [ABSTRACT FROM AUTHOR]

This paper presents a case study on the prospects of bathing in a large water course (das Velhas River, Brazil), which crosses the important metropolitan region of Belo Horizonte (25 municipalities), receiving several point and diffuse discharges. The studies were carried out based on a mathematical simulation of thermotolerant coliforms over 227 km of the river, using an adaptation of the Qual2E model (model Qual-UFMG). Simulations of intervention scenarios were made for the current conditions, with three reference flows for the das Velhas River, tributaries and direct contribution: Q7,10 (representative of low-flow conditions), Q50 (average conditions) and Q10 (rainy season). The intervention scenarios simulated were: (a) current conditions without intervention; (b) scenario with effluent disinfection in the two largest wastewater treatment plants in the basin (around 2.4 million inhabitants); (c) scenario with 95% sewage collection and treatment, with disinfection in all municipalities of the study area; (d) scenario with the calculation of values required for the coverage of sewage treatment and coliform removal efficiencies based on a mathematical optimization process. The monitoring data and results of all simulations indicated improvement in coliform concentration as the river flows downstream. However, results suggested that disinfection per se is not enough. Even under hypothetical conditions of excellent sanitary infrastructure for a developing country, coverage of collection and treatment of 95% of the generated sewage, and treatment with disinfection at all wastewater treatment plants, concentrations of thermotolerant coliforms in das Velhas River are likely to be above the maximum allowable of 1,000 MPN/100 mL for bathing purposes. The mathematical optimization indicated the need for very high percentages of sewage treatment coverage (near 100%, i.e. universality of collection and treatment) and implementation of disinfection in most treatment plants in the basin, and highlighted the fact that both items play equally important roles. [ABSTRACT FROM AUTHOR]

Scenario-based pollutant load analysis was conducted to develop a part of a concept for planning and management of wastewater treatment systems (WWTSs) under the mixture conditions of centralised and on-site WWTSs. Pollutant discharge indicators and pollutant removal efficiency functions were applied from another paper in the series, which were developed based on the existing conditions in urban and peri-urban areas of Bangkok, Thailand. Two scenarios were developed to describe development directions of the mixture conditions. Scenario 1 involves keeping the on-site wastewater treatment plants (WWTPs) within the areas of centralised WWTSs. Scenario 2 is dividing the centralised and on-site WWTS areas. Comparison of the smallest values of total pollutant discharge per capita (PDCtotal) between Scenarios 1 and 2 showed that the smallest PDCtotal in Scenario 1 was smaller than that in Scenario 2 for biological oxygen demand, chemical oxygen demand and total phosphorus whereas the smallest PDCtotal in Scenario 2 was smaller than that in Scenario 1 for total nitrogen, total coliforms and faecal coliforms. The results suggest that the mixture conditions could be a possible reason for smaller pollutant concentrations at centralised WWTPs. Quantitative scenario-based estimation of PDCtotal is useful and a prerequisite in planning and management of WWTSs. [ABSTRACT FROM AUTHOR]

Urbanization and frequent storms play important roles in increasing faecal bacteria pollution, especially for tropical urban catchments. However, only little information on the faecal bacteria levels from different land use types and the factors that influence bacteria concentrations is available. Thus, the objectives of this study were to quantify the levels and transport mechanism of faecal coliforms (FCs) from residential and commercial catchments. Stormwaters were sampled and the runoff flow rates were measured from both catchments during four storm events in Skudai, Malaysia. The samples were then analysed for FC, biochemical oxygen demand (6005). chemical oxygen demand (COD), total suspended solids (TSS) and ammoniacal-nitrogen (NH3i-N) concentrations. Intra-storm and inter-storm characteristics of FC bacteria were investigated in order to identity the level and transport pattern of EC. The commercial catchment showed significantly higher event mean concentration (EMC) of FC than the residential catchment. For the residential catchment, the highest bacterial concentrations occurred during the early part of stormwater runoff with peak concentrations usually preceding the peak flow. First flush effect was more prevalent at the residential catchment. [ABSTRACT FROM AUTHOR]

Diverse fecal and nonfecal bacterial contamination and nutrient sources (e.g. agriculture, human activities and wildlife) represent a considerable non-point source load entering natural recreational waters which may adversely affect water quality. Monitoring of natural recreational water microbial quality is most often based mainly on testing a set of microbiological indicators. The cost and labour involved in testing numerous water samples may be significant when a large number of sites must be monitored repetitively over time. In addition to water testing, ongoing monitoring of key environmental factors known to influence microbial contamination may be carried out as an additional component. Monitoring of environmental factors can now be performed using remote sensing technology which represents an increasingly recognized source of rigorous and recurrent data, especially when monitoring over a large or difficult to access territory is needed. To determine whether this technology could be useful in the context of recreational water monitoring, we evaluated a set of agroenvironmental determinants associated with fecal contamination of recreational waters through a multivariable logistic regression model built with data extracted from satellite imagery. We found that variables describing the proportions of land with agricultural and impervious surfaces, as derived from remote sensing observations, were statistically associated (odds ratio, OR = 11 and 5.2, respectively) with a higher level of fecal coliforms in lake waters in the southwestern region of Quebec, Canada. From a technical perspective, remote sensing may provide important added-value in the monitoring of microbial risk from recreational waters and further applications of this technology should be investigated to support public health risk assessments and environmental monitoring programs relating to water quality. [ABSTRACT FROM AUTHOR]

The reclamation of domestic wastewater for irrigation is one alternative approach to solve the water scarcity crisis, but it is essential to control the microbiological quality of wastewater used for irrigation. The removal of thermotolerant coliforms, also known as faecal coliforms (FC), from treated domestic wastewater by intermittent media infiltration (IMI) in column was studied. The columns were filled with natural filter media (soil, soil/charcoal and zinc-modified zeolite, Zeo-Zn), and wastewater, IMI-treated wastewater and disinfected wastewater were compared. The numbers of residual FC on Swiss chard (Beta vulgaris) and in agricultural soil were determined over a 4-month period. The column using Zeo-Zn had a higher FC removal efficiency (2.98 log) than columns with other filter media and disinfection (1 .87-2.57 log) due to the bactericidal properties of Zn2+. The treatment of wastewater using Zeo-Zn and disinfection both decreased the accumulation of FC on plants and in soil to approximately 1-20 MPN/g dry matter. MI-treated wastewater using the column with Zeo-Zn was suitable for unrestricted agricultural use, complied with Mexican regulations (as did disinfectedwastewater) and had a low risk of FC contamination of plants and soil. [ABSTRACT FROM AUTHOR]

High levels of environmental contamination, often associated with improper waste and excreta management, are widespread among informal settlements within urban areas in developing countries. We determined the level of faecal contamination in domestic water sources and evaluated the potential contribution of these water sources to intestinal helminthiases in seven informal settlements of Kisumu City, western Kenya. Membrane filtration technique was used for enumeration of total and (aecal (Escherichia coli) coliform bacteria in water samples collected from dams, rivers, springs and wells. Out of the 80 water sources sampled, 76 (95%) were highly contaminated with E. coli. All water samples from unprotected wells (26) and 92.6% of samples from protected wells (25) were positive for E. coli. The highest and lowest E. coil densities were observed in samples from dams (3,800 ± 1,807 coliforms per 100 ml) and boreholes (419 ± 223 coliforms per 100 ml), respectively (p = 0.0321). Distance from pit latrines was negatively associated with E. coli coliform density for wells (r= -0.34, n = 53, p = 0.0142). Untreated well-water may not be suitable for human consumption, and its continued use constitutes a major health risk for the inhabitants of these informal settlements. [ABSTRACT FROM AUTHOR]

There is increasing concern regarding spread and proliferation of pathogenic microorganisms in watersheds and their impacts on water quality, in agricultural and rural watersheds fecal coliform occurrence, an indicator of pathogenic contamination, is often thought to be a result of land applications of animal waste. This study used the Hydrologic Simulation Program Fortran (HSPF) along with the Bacterial Indicator Tool to model feca coliform transport in a coastal watershed with a view to identifying contaminant sources and key contributing areas. Results indicated that the highest levels of fecal coliform contamination (often exceeding the 400 counts/i 00 ml standard for the area) emanated from areas with and without livestock operations, and from largely forested areas, indicating that livestock operations were not the determining source of fecal coliform as suggested in previous studies. This study found HSPF to be an effective tool for identifying key coliform contributing areas in coastal watersheds. [ABSTRACT FROM AUTHOR]

The filtration of fecal coliform from a secondary clarifier effluent was investigated using direct rapid sand filters as tertiary wastewater treatment on a pilot scale. The effect of the flocculation dose, flow loading rate, and grain size on fecal coliform removal was determined. Direct rapid sand filters can remove 0.6-1.5 log-units of fecal coliform, depending on the loading rate and grain size distribution. Meanwhile, the flocculation dose has little effect on coliform removal, and increasing the loading rate and/or grain size decreases the bacteria removal efficiency. A model was then developed for the removal process. Bacteria elimination and inactivation both in the water phase and the sand bed can be described by first-order kinetics. Removal was successfully simulated at different loading rates and grain size distributions and compared with the data obtained using pilot-scale filters. [ABSTRACT FROM AUTHOR]

Measurements of primary productivity of phytoplankton and enumeration of the counts of coliform and heterotrophic bacteria (HB) were made in the water of 12 experimental tanks used for 3 treatments and control in triplicate as follows: (a) fresh human urine (0.02%), (b) stored human urine (0.02%), (c) mixed urine of fresh and stored human urine (0.02%) and (d) control without input of urine. The gross primary productivity of phytoplankton was highest in the stored urine treated tanks (508 mg C m-2 h-1) followed by fresh urine (353 mg C m-2 h-1), mixed urine (303 mg C m-2 h-1) and control (215 mg C m-2 h-1). Similar was the response of net primary production of phytoplankton. The mean count of HB observed in stored urine fed tanks was significantly higher (59-184%) than the remaining urine fed treatments. The mean count of Escherichia coli did not differ from urine treated tanks to control implying the good quality of water. The concentration of dissolved oxygen of water (7.6 to 12.8 mg L-1) in these tanks remained satisfactory for aquaculture. The mean concentration of ammonium-N observed in fresh urine treated tanks was more than 10 times higher than the remaining treatments employed. In contrast, the level of phosphate and electrical conductivity in the stored urine treated tanks were significantly higher than the remaining treatments. It is proposed that stored urine with a significantly reduced load of E. coli might be an effective low cost liquid fertilizer for algal biomass production. [ABSTRACT FROM AUTHOR]

The purpose of this research was to determine the feasibility of a UV photoreactor for the disinfection of effluent from a polishing pond following a UASB reactor treating domestic wastewater. For this, a 20 mm diameter photoreactor (20.7 litre volume) equipped with four 30 W submerged low-pressure mercury arc lamps was used. Three tests with contact times and doses ranging from 45 to 90 s and from 16.9 to 31.3 mW s cm-2 were carried out. Inactivation of total coliforms and Escherichia coli varied from 2.6 to 3.4 log-units, even with the presence of suspended solids in the range of 87 to 102 mg L-1. These results have shown that UV radiation disinfection of pond effluents can be a feasible alternative in areas with land restriction. [ABSTRACT FROM AUTHOR]

WSP technology has been used in Ceará, Northeast Brazil, since middle 1970s. There are presently 96 ponds plants and most of them are comprised by single cells (40%) and series of 3 ponds (35%). They were under loaded due to incomplete house connections to the sewerage network and low per capita wastewater contributions. Highest removal rates of organic material, ammonia and faecal coliform were found in 3 pond series. Faecal coliform removal was in accordance with the literature and series of ponds reached numbers ⩽105 cells/100 ml. In series with 4 and 5 ponds FC was below 103 cells/100 ml. Ammonia removal varied from 30 to 80% and total phosphorus the removal was not significant. An increase in the number of maturation ponds enhances nutrient and coliform removal. Up-grading schemes should be investigated as well as effluent reuse potential. [ABSTRACT FROM AUTHOR]

This paper presents the results of five years monitoring of an experimental wastewater treatment plant in southeast Brazil, comprised of a UASB reactor followed by a submerged aerated biofilter (BF) (field scale) and shallow polishing ponds (pilot scale). Three ponds in series achieved high quality effluent standards in terms of ammonia and E.coli, but a fourth pond did not result in further efficiency. Well established models to predict ammonia and E.coli removal in facultative and/or maturation ponds were, in a way, validated for polishing ponds too. The paper also includes results of input design parameters, such as pH and E.coli die-off rate constants, and their variation along the pond series. [ABSTRACT FROM AUTHOR]

Performance of the combined process of up-flow anaerobic sludge blanket (UASB) reactor and cascade sponge reactor (CSR) for sewage treatment was studied. UASB-CSR system was operated at HRTs of 24 h, 16 h, and 8 h at an average wastewater temperature of 29°C. It comprises of the most efficient combined process not only for CODT (98.9%), BODT (98.5%), TSS (99.3%), total nitrogen (89.1%), total phosphorus (99.0%), total coliform (99.9%) and fecal coliform (99.9%) removal but also for reducing excess sludge production. Fecal coliform counts were found 23 MPN/100 ml only in final effluents. The effluent quality of the system sufficiently meets the discharged standards which regulate wastewater discharge into drains. The parameters of CSR are closely related to those of the potable water after certain advanced treatment which can be reused in many ways. Moreover, it does not require any external aeration and thus the cost associated with energy and devices required for aeration are cut to zero. [ABSTRACT FROM AUTHOR]

This study evaluates the performance of four 2.3 m deep pilot-scale, independently loaded, primary facultative ponds treating predominantly domestic sewage in northeast Brazil. The ponds contained longitudinal baffles giving different length to width ratios from 3.55 to 32.4. The ponds had mean hydraulic retention times of ∼15 days, and mean surface organic loadings of 330 kg BOD5.ha.d-1 during the first experimental phase and 375 kg BOD5.ha.d-1 in the second. The vertical inlets and outlets pipes were positioned at 1.8 m and 5 cm respectively below the pond surface in the first phase and at 50 cm and 1.8 m respectively in the second. All the ponds functioned as efficient primary facultative ponds but statistical analysis demonstrated no differences in effluent quality for most of the parameters measured for the various configurations of baffles and inlet and outlet depths. All behaved similarly to the unbaffled pond. The only exceptions were suspended solids and chlorophyll a concentrations which tended to be lower for all combinations of baffles with the outlets set 1.8 m below the surface. This study suggested that the longitudinal baffling of primary facultative ponds when using vertical inlets and outlets may well not significantly improve pond performance. [ABSTRACT FROM AUTHOR]

Chlorination and UV irradiation of RBC (rotating biological contactor)-treated light GW (greywater) was investigated. The ability of chlorine and UV to inactivate indictor bacteria (FC - Faecal Coliforms, HPC - Heterotrophic Plate Count) and specific pathogens (P.a. - Pseudomonas aeruginosa sp., S.a. - Staphylococcus aureus sp.), was assessed and their regrowth potential was examined. The RBC removed 88.5-99.9% of all four bacteria groups. Nevertheless, the treated GW had to be disinfected. Most of the chlorine was consumed during the first 0.5 h, while later its decay rate decreased significantly, leaving enough residual after 6 h to prevent regrowth and to further inactivate bacteria in the stored GW effluent. Under exposure to low UV doses (⩽69 mJ/cm2) FC was the most resistant bacteria group, followed by HPC, P.a. and S.a. Exposure to higher doses (⩽439 mJs/cm2) completely inactivated FC, P.a. and S.a., while no further HPC inactivation was observed. FC, P.a. and S.a. did not exhibit regrowth after exposure to all the UV doses applied (up to 6 h storage). HPC did not exhibit regrowth after exposure to low UV doses (19-69 mJ/cm2), while it presented statistically significant regrowth in un-disinfected effluent and after exposure to higher UV doses (147-439 mJ/cm2). [ABSTRACT FROM AUTHOR]

in India, recently, upflow anaerobic sludge blanket (UASB) based sewage treatment plants (STP5) have come up in a big way. Sequence adopted: screens- grit chambers- UASB reactors followed by one-day detention ponds (DP). Performance of DPs located at five STP5 (27-70 MUd) was evaluated over a period of one year from July 2004 to July 2005. The installation of these non-algal ponds reduced land requirement, but from treatment point of view it at best offered only removal of solids washed out of the UASB reactor. Total coliform count in the effluent from ponds ranging from 106 to 109 MPN/100 mL is more than the maximum permissible limit of 10,000 MPN/100 mL A need has, therefore, been felt to evaluate the possibility of aerating the effluent from UASBR. During aeration, ORP and DO increase, whereas COD and BOO decrease. In a continuous aeration -50% reduction in COD and nearly 50% increase in DO saturation (DO/DOs) can be achieved by increasing ORP from -100 to 122 my. Regression equation established between ORP and COD/CODi/Do/DOs may find wide application. [ABSTRACT FROM AUTHOR]

The Sulfate Reduction, Autotrophic Denitrification, Nitrification Integrated (SANI) process has been specially designed to treat saline wastewater. In the process no biological excess sludge is produced. SANI process also has the added advantages of cost and footprint reduction when compared to traditional activated sludge processes. In the SANI pilot plant, the fecal coliform removal efficiency in the sulfate reducing up-flow sludge bed (SRUSB) was found to be 1.4 log, whereas that in the subsequent anoxic and aerobic reactors it was 0.6 and 0.2 log, respectively, leading to a relatively high overall coliform removal of 2.210g. Sulfide was confirmed to be toxic to fecal coliform and the contact time between the sulfide produced and coliform in the SRUSB played an important role in the removal. [ABSTRACT FROM AUTHOR]

In this study, operation and maintenance performance in two long-term operating Membrane Bioreactor (MBR) wastewater treatment facilities were investigated. One facility in Japan started its operation in 1999 showed that both effluent BOD and n-hexane extracts were less than 5 mg/L, and a cumulative replacement percentage (CR%) of membrane cartridges was 7.8% as of 2008. Another facility in the United Kingdom (UK) started its operation in 1998 showed that average effluent BOD was less than 5 mg/L and more than 5-log removal of faecal coliforms was maintained. The CR% was 6.4% as of 2008. Amongst 95 facilities in Europe, the CR% was 6.4% after 5-year operation. In order to inspect product quality of membrane cartridges after 10-year operation in the UK facility, clean water flow (CWF) rate and pore size distribution were measured. The CWF rate was approximately 100% of that of new membrane cartridge's, and the pore size distribution was well maintained at less than 0.46mm. A microscopic observation showed some scratches on the membrane surface. However, they did not lead to deteriorate permeate quality. These data suggested that the membrane cartridges can be used as long as 10 years. [ABSTRACT FROM AUTHOR]

This study investigated the regrowth of total coliform, Salmonella, and Clostridium perfringens in anaerobically digested sludge after centrifuge dewatering in the presence and absence of daylight. Sludge cake and centrate samples were collected from a treatment plant, and half of the samples was stored in daylight and the other half was stored in dark for three weeks. The bacteria levels in the cake and centrate samples were measured periodically throughout the storage period, and all three bacteria showed substantial regrowth. Presence of daylight increased the regrowth of Salmonella both in sludge cake and centrate, and increased the regrowth of total coliform in centrate. Salmonella exhibited the highest regrowth rate in cake among the three bacteria tested both in the presence and absence of light. Daylight did not appear to have a significant impact on the regrowth of Clostridium perfringens in cake and centrate, and on the regrowth of total coliform in cake. This might, however, be caused by the masking effect of the higher initial numbers of these bacteria in the samples. There is need for more research to thoroughly understand the effect of daylight on the regrowth of sludge bacteria. [ABSTRACT FROM AUTHOR]

The dynamic, hemolytic and hemagglutination activities and the antibiotic resistance of non-O1 Vibrio cholerae, Pseudomonas aeruginosa, faecal coliforms (FC) and faecal streptococci (FS), isolated by standard membrane filtration methods from suburban and rural groundwater supplies, were carried out. Detectable non-O1 V. cholerae and P. aeruginosa was present in 81% and 88% of samples. The total occurrence of FC and FS during the period of study was 94%. The annual average densities of non-O1 V. cholerae were 4,903 MPN/100 mL. While, they were 206, 1,891 and 1,246 cfu/100 mL for P. aeruginosa, FC and FS respectively. Non-O1 V. cholerae strains had the highest percentage of hemolytic activities (a + b) (71.29%), whereas 20.71% of FS, 16.88% of FC and 9.13% of P. aeruginosa strains produced hemolysin. Bacterial strains isolated were found to be adhesive, with percentages of 63.09%, 65.09%, 84.06% and 87.98% respectively for non-O1 V. cholerae, FS, FC and P. aeruginosa. As for antibiotic resistance, the overall resistance of non-O1 V. cholerae strains was 79%, whereas it was 100% for the other bacteria. Non-O1 V. cholerae resistance was expressed towards sulfamethoxazole (75%), streptomycin (62%) and cephalothin (60%). Obtained results indicated correlation between bacteriological pollution and their public health implications. [ABSTRACT FROM AUTHOR]

This paper summarises the physicochemical and microbiological quality of water from a rainwater harvesting (RWH) system in a UK-based office building. 7 microbiological and 34 physicochemical parameters were analysed during an 8 month period. Physicochemically, harvested rainwater quality posed little health risk; most parameters showed concentrations below widely used guideline levels for drinking water. However, RWH system components (e.g. fittings and down pipes) appear to be affected soft water corrosion, resulting in high concentrations of some metals (copper, zinc and aluminium). This suggests the material selection of such fittings should be considered keeping in view the hardness of rainwater of an area. Microbiologically, Cryptosporidium, Salmonella and Legionella were not present in the samples analysed. However, faecal coliform counts were high at the beginning of the study, but did decrease over time in weak correlation with increasing pH. Enterococcus faecalis displayed counts consistently above UK rainwater harvesting standards. Inappropriate roof and rainwater good design, as well as material selection appear to be responsible for the reduced microbial quality, as they promoted contributions from avian sources and inhibited cleaning activities. Building and RWH system designs require greater consideration of local factors, which are critical for optimising harvested rainwater quality, to prevent both the development of contaminated sediments and health impacts. [ABSTRACT FROM AUTHOR]

In order to understand the current status of rainwater harvesting (RWH) practices in Taiwan's schools, a study was carried out to examine the RWH system performance, water usage, and water quality in these sites. A total of 29 schools in various regions were selected for this investigation, including 7 in the northern, 7 in the central, 8 in the southern, and 7 in the eastern regions of Taiwan. Water quality indicators tested were: pH, temperature, conductivity, oxidation-reduction potential, suspended solid, total organic carbon, fecal coliform, and total coliform. From this study, it was found that RWH systems in these sites generally had two different designs: one that collected rainwater only, and one that collected both rainwater and grey water. From statistical analysis, it was found that water quality indicators such as suspended solids, total organic carbon, and fecal coliform were significantly affected by the water source and site location. Fecal coliforms in most of the sites we studied were high and not qualified for toilet flushing. The average water retention time of 2.4 months was long and considered to be the main reason to cause high fecal coliform counts. Finally, the benefit analysis was conducted to evaluate economic feasibility of rainwater harvesting for these schools. It turned out that 20% of them were able to gain economic benefits from using rainwater. [ABSTRACT FROM AUTHOR]

The occurrence of resistance patterns among wastewater fecal coliforms was determined in the study. Susceptibility of the isolates was tested against 19 antimicrobial agents: aminoglycosides, aztreonam, carbapenems, cephalosporines, b-lactam/b-lactamase inhibitors, penicillines, tetracycline, trimethoprim/sulfamethoxazole, and fluoroquinolones. Additionally the removal of resistant isolates was evaluated in the laboratory-scale wastewater treatment model plant (M-WWTP), continuously supplied with the wastewater obtained from the full-scale WWTP. Number of fecal coliforms in raw (after mechanical treatment) and treated wastewater, as well as in aerobic chamber effluent was determined using selective medium. The selected strains were identified and examined for antibiotic resistance using Phoenix Automated Microbiology System (BD Biosciences, USA). The strains were identified as Escherichia coli (n = 222), Klebsiella pneumoniae ssp. ozaenae (n = 9), and Pantoea agglomerans (n = 1). The isolate of P. agglomerans as well as 48% of E. coli isolates were sensitive to all antimicrobials tested. The most frequent resistance patterns were found for ampicillin: 100% of K. pneumoniae ssp. ozaenae and 41% of E. coli isolates. Among E. coli isolates 12% was regarded as multiple antimicrobial resistant (MAR). In the studied M-WWTP, the applied activated sludge processes reduced considerably the number of fecal coliforms, but increased the ratio of antimicrobial-resistant E. coli isolates to sensitive ones, especially among strains with MAR patterns. [ABSTRACT FROM AUTHOR]

Bioflims in surface waters primarily consist of allochthonous microorganisms. Under conditions of pollution faecally derived bacteria may interact with these bioflims. Total coliform bacteria, Escherictiia coli and intestinal enterococci are used to monitor source water quality, indicating faecal pollution and the possible presence of enteric pathogens. In the present study the occurrence of faecal indicators was investigated in biofilms (epilithic biofilms, sediments) of German rivers. All of the biofilms contained significant concentrations of these bacteria, which were several orders of magnitude lower compared with the total cell number and the number of culturable heterotrophic plate count bacteria indicating that faecal indicator bacteria represented a minor fraction of the whole biofilm communities. The biofilms displayed approximately two orders of magnitude higher concentrations of total coliforms, E. coli and enterococci compared with the overlying water. Identification of coliform and enterococcal isolates from the biofilms revealed the presence of species which are known to be opportunistic pathogens. Overall, the results of the present study show that faecal indicator bacteria can survive in the presence of high cell densities of the authochthonous microflora in epilithic biofilms and sediments, suggesting that these biofilms may act as a reservoir for bacterial pathogens in polluted rivers. [ABSTRACT FROM AUTHOR]

The study used existing indicator bacterial data and a number of physicochemical parameters that can be measured instantaneously to determine if a decision tree approach, especially classification and regression tree, could be used to predict bacterial concentrations in timely manner for beach closure management. Each indicator bacteria showed different tree structures and each had its own significant variables; Dissolved oxygen played an important role for both total coliform and fecal coliform and turbidity was the most important factor to predict concentrations of enterococci for decision tree approaches. Root mean squared error stayed between 5 and 6.5% of the average values of observations; RMSEs from each simulation, 0.25 for total coliform, 0.31 for fecal coliform, and 0.29 for enterococci. Estimations from tree structures would be regarded as a good representation of the actual data. In addition to results of the objective function, RMSE, 77.5% of actual value fell into the 95% of confidence interval of estimations for total coliform concentrations, 60% for fecal coliform concentrations, and 62.5% for enterococci concentrations. The approach showed reliable estimations for the majority of the data processed, although the method did not portray low concentrations of bacteria as well. [ABSTRACT FROM AUTHOR]

An 8 month investigation into the quality of water from open and rope-pump shallow wells in rural Cambodia was conducted. Wells were analysed for indicators of the health (arsenic, fluoride, manganese, nitrate, total coliforms, E. coli, male-specific coliphage) and aesthetic (iron, chloride, conductivity, total dissolved solids, hardnesss, turbidity, pH) quality of the water, and referenced to the Cambodian Drinking Water Standard when available. The shallow aquifer was chemically less of a health risk than the deep aquifer; however, microbial contamination was considerable for both shallow well types with mean E. coli loads of 103 CFU/100mL and male-specific coliphage contamination of 102 PFU/eluate. Temporal variation in microbial contamination was significant ( p , 0.05), with overall loads decreasing during the dry season. The aesthetic quality of the water was poor for all samples, but worsened during the dry season. No significant difference was observed in the quality of water from open and rope-pump wells, despite their classification as unimproved and improved respectively by the WHO/UNICEF Joint Monitoring Programme. Contaminants present in both well types may readily be removed by simple water treatment, suggesting that household treatment may be more beneficial to rural Cambodian households than shallow aquifer source improvements. [ABSTRACT FROM AUTHOR]

In this study ten laboratories in Greece compared the performance of reference method TTC Tergitol 7 Agar (with the additional test of b-glucuronidase production) with five alternative methods, to detect E. coli in water, in line with European Water Directive recommendations. The samples were prepared by spiking drinking water with sewage effluent following a standard protocol. Chlorinated and non-chlorinated samples were used. The statistical analysis was based on the mean relative difference of confirmed counts and was performed in line with ISO 17994. The results showed that in total, three of the alternative methods (Chromocult Coliform agar, Membrane Lauryl Sulfate agar and Trypton Bilex-glucuronidase medium) were not different from TTC Tergitol 7 agar (TTC Tergitol 7 agar vs Chromocult Coliform agar, 294 samples, mean RD% 5.55; vs MLSA, 302 samples, mean RD% 1; vs TBX, 297 samples, mean RD% 22.78). The other two alternative methods (Membrane Faecal coliform medium and Colilert 18/ Quantitray) gave significantly higher counts than TTC Tergitol 7 agar (TTC Tergitol 7 agar vs MFc, 303 samples, mean RD% 8.81; vs Colilert-18/Quantitray, 76 samples, mean RD% 18.91). In other words, the alternative methods generated performance that was as reliable as, or even better than, the reference method. This study will help laboratories in Greece overcome culture and counting problems deriving from the EU reference method for E. coli counts in water samples. [ABSTRACT FROM AUTHOR]

Concerns about water shortage and pollution have received increased attention over the past few years, especially in developing countries with warm climate. In order to help local water management in these countries, the Euro-Mediterranean Regional Programme (MEDA) has financed the Zer0-m project (www.zer0-m.org). As a part of this project, several constructed wetland (CW) pilot systems with different pre-treatments have been implemented in four Technological Demonstration Centres in Egypt, Morocco, Tunisia and Turkey. The aim of this research was to establish appropriate designs for treatment of segregated domestic black (BW) and grey water (GW). We tested several different multistage CW configurations, consisting of horizontal and vertical subsurface flow CW for secondary treatment and free water systems as tertiary stage. CW removal efficiencies of TSS, COD, BOD5, N-NH+4 , N-NO3, Ntot, total coliforms (TC) were evaluated for each of the implemented systems. The results from this study demonstrate the potential of CWs as a suitable technology for treating segregated domestic wastewater. A very efficient COD reduction (up to 98%) and nitrification (92-99%) was achieved for BW and GW in all systems. CW effluent concentrations were below 15 mg/L for BOD5, 1 mg/L for N-NO3 and 0.5 mg/L for N-NH+4 together with acceptable TC counts. Based on these results, we suggest adopting the design parameters used in this study for the treatment of segregated wastewater in the Mediterranean area. [ABSTRACT FROM AUTHOR]

Water quality of the Zayandehrud River, located in an arid region of central part of Iran, was assessed using National Sanitation Foundation Water Quality Index (NSF WQI) calculated by four aggregation methods. Water samples were collected monthly (July 2006 to June 2007) from eight stations in the middle of the river. The parameters required for the NSF WQI calculations including saturation percent of dissolved oxygen, biochemical oxygen demand, fecal coliforms, pH, nitrate, total phosphate, temperature deviation, total dissolved solids and turbidity were measured. According to WQIm which appeared to be more adapted to environmental conditions of the Zayandehrud River, the studied section of the river was considered as "reasonable" to "polluted" water quality. All of the calculated water quality indices showed the lowest values in August. In addition to BOD5 and fecal coliform amounts which were generally high, nitrate and total phosphate concentrations were also considerably increased due to agriculture practices in August. Generally, BOD5 and fecal coliforms are the main water quality subindices that reflect the effect of anthropogenic activities on the water quality of this river. [ABSTRACT FROM AUTHOR]

The treatment of stormwater using surface constructed wetlands has become common in the last decades. However, the use of constructed wetlands for stormwater management has not been thoroughly evaluated in their capacity to treat microbial loads. The case studies presented in this paper are situated at Lake Macquarie, a large estuarine lagoon located approximately 150km north of Sydney, Australia. To protect the lake ecosystem from the impact of increasing urban development, the local Council constructed numerous stormwater quality improvement devices (SQIDs) at selected locations. The SQIDs typically consisted of trash racks, gross pollutant traps and surface constructed wetlands. To evaluate the effectiveness of three of these devices in reducing faecal contamination, water samples were collected for faecal coliforms (FC) during and following rainfall at inlets and outlets of the structures. Results indicated one of the SQIDs as the most efficient for bacterial reduction, while the other two provided low or non reduction of FC. Results also illustrated dependence of bacteria reduction on flow conditions. Comparison of devices suggested that hydraulic residence times and other design parameters strongly influenced the capacity of each device to reduce FC counts during different weather conditions. [ABSTRACT FROM AUTHOR]

Efficiency of solar disinfection (SODIS) was evaluated for the potability of rainwater in view of the increasing water and energy crises especially in developing countries. Rainwater samples were collected from an underground storage tank in 2 L polyethylene terephthalate (PET) bottles and SODIS efficiency was evaluated at different weather conditions. For optimizing SODIS, PET bottles with different backing surfaces to enhance the optical and thermal effects of SODIS were used and different physicochemical parameters were selected and evaluated along with microbial re-growth observations and calculating microbial decay constants. Total and fecal coliforms were used along with Escherichia Coli and Heterotrophic Plate Counts (HPC) as basic microbial and indicator organisms of water quality. For irradiance less than 600W/m², reflective type PET bottles were best types while for radiations greater than 700W/m², absorptive type PET bottles offered best solution due to the synergistic effects of both thermal and UV radiations. Microbial inactivation did not improve significantly by changing the initial pH and turbidity values but optimum SODIS efficiency is achieved for rainwater with acidic pH and low initial turbidity values by keeping air-spaced PET bottles in undisturbed conditions. Microbial re-growth occurred after one day only at higher turbidity values and with basic pH values. First-order reaction rate constant was in accordance with recent findings for TC but contradicted with previous researches for E. coli. No microbial parameter met drinking water guidelines even under strong experimental weather conditions rendering SODIS ineffective for complete disinfection and hence needed more exposure time or stronger sunlight radiations. With maximum possible storage of rainwater, however, and by using some means for accelerating SODIS process, rainwater can be disinfected and used for potable purposes. [ABSTRACT FROM AUTHOR]

The density and distribution of bacteria indicative of pollution in the surface microlayer and subsurface water of the River Slupia were estimated. The number of heterotrophic bacteria, total coliforms, fecal coliforms and fecal streptococci were higher in the surface microlayer than in the underlying water. The average bacterial enrichment factor (EF) of the parameters studied in the bacterioneuston was 1.7 to 1.8 times higher than in bacterioplankton. During the annual study cycle, bacterial pollution indicators inhabiting the surface microlayer and subsurface water showed considerable monthly changes. [ABSTRACT FROM AUTHOR]

Recent research efforts demonstrated an increase in fecal coliform counts in anaerobically digested biosolids after dewatering. Variety of bacteria enters viable but nonculturable (VNC) state as a survival response when exposed to environmental stress. Increase in coliform concentration after digestion and dewatering processes have been attributed to cells going into a viable but non-culturable state implying that traditional coliform enumeration methods are not sufficient to determine number of viable cells. Therefore, this research has been undertaken to develop a method for rapid and accurate quantification of viable but non-culturable pathogens in biosolids via monitoring and quantifying stress-related genes in Salmonella sp. The proposed method has the potential to allow accurate detection of pathogens in biosolids even when the cells are non-culturable due to environmental stress. The research proposed identification of stress related genes in Salmonella when cells are exposed to heat for different durations by using available Salmonella microarrays. In the context of this study the identified stress genes can be quantified through reverse transcription, complementary DNA (cDNA) synthesis, and amplification of cDNA via quantitative reverse transcription polymerase chain reaction (qRT-PCR). Then quantity of mRNA can be correlated to cell viability and cells ability to grow, i.e., their culturability. Development of a novel approach to understand the pathogen behaviour in biosolids is key to ensure low public health risks from biosolids. Nevertheless, the initial results suggest that intact RNA isolation from biosolids is still challenging task. [ABSTRACT FROM AUTHOR]

In order to gain knowledge on the presences of bacteria and viruses in urban waters, the authors started a long-term study on the microbiological quality of urban lakes and rivers in Xi'an, China. In the current study, enteroviruses were chosen as typical viruses and RT-nested PCR was conducted for their detection. Universal primers were designed for simultaneous detection of poliovirus, coxsackievirus, and enterovirus 71 which are the most frequently encountered enteroviruses in China. The RT-nested PCR protocol established in this study showed high sensitivity and specificity. The detection limit was equivalent to 0.038 CCID50 per litre by applying a modified adsorption-elution concentration method. No cross-reactivity was observed using the genome of pathogenic bacteria as of PCR template. The occurrence of enteroviruses was compared with fecal coliform count in a 6-month period from July to December 2006 for the urban waters. As a result, it was noticed that the presence of enteroviruses might not relate to the fecal coliform count so much. Statistical analysis also indicated that there was no significant correlation between the presence of enteroviruses and that of total bacteria, total coliform, and fecal coliform. [ABSTRACT FROM AUTHOR]

The effect of the use of treated wastewater on the growth of cabernet sauvignon and merlot grapes from the Guadalupe Valley, Mexico was evaluated. Secondary advanced effluent was used to irrigate the grapevines at a rate of 66 L/vine/week. Wastewater quality results confirmed that all parameters complied with Mexican legislation for crop irrigation as well as reuse in activities in which the public would be in direct or indirect contact with the reclaimed water. Results showed that the number of leaves per shoot and the overall biomass increased in plants irrigated with wastewater and grape production per plant was 20% higher. The concentration of carbohydrates, organic acids and pH were similar in grapes from vines irrigated with wastewater to those irrigated with groundwater. Throughout the experiment, no fecal coliform bacteria were detected in the cultivated grapes. The wastewater caused an increase in the biomass of the grapevines and there was no presence of microbial indicators in the final product so a higher wine production could be achieved without an increase in health risk related problems. If 200 L/s of reclaimed wastewater would be returned to be used for grapevine irrigation in Valle de Guadalupe (the same amount that is currently being sent as drinking water to Ensenada), assuming an irrigation application of 6,000-7.500m3/ha/year, approximately 837-1046 hectares (ha) of grapevines could be irrigated. Part of ongoing research includes an economical analysis of the best options for Ensenada and the Valle de Guadalupe in order to establish the optimum volume of water to be returned, the cost of its transportation, as well as the cost of irrigation. [ABSTRACT FROM AUTHOR]