Total Coliform Concentrations Research Articles

Tradeoffs between pathogen inactivation and disinfection byproduct formation during sequential chlorine and chloramine disinfection for wastewater reuse

Treatment of fully nitrified municipal wastewater effluents with chlorine followed by chloramines (i.e., sequential chlorine disinfection) upstream of advanced treatment trains can contribute pathogen inactivation credits for potable reuse while leaving a chloramine residual to control biofouling on membrane units in the advanced treatment train. However, free chlorine exposures must be optimized to maximize pathogen inactivation while minimizing the formation of disinfection byproducts (DBPs) that are challenging to remove in the advanced treatment train. Using a pilot-scale disinfection contactor receiving fully-nitrified, tertiary municipal wastewater effluent, this study found that a 3 mg × min/L free chlorine CT (i.e., the product of the chlorine residual “C” and the contact time “T”) followed by a 140 mg × min/L chloramine CT could reliably achieve 5-log inactivation of MS2 bacteriophage and reduce median total coliform concentrations below 2.2 MPN/100 mL. Free chlorine disinfection was equally effective when chlorine was dosed to exceed the breakpoint for 1 mg/L of ammonia as N. At this free chlorine exposure, regulated trihalomethane (THM) and haloacetic acid (HAA) formation remained below their Maximum Contaminant Levels (MCLs), but NDMA concentrations of ∼30 ng/L were above the 10 ng/L California Notification Level. Increasing the free chlorine exposure to ∼30 mg × min/L increased THM and HAA formation, with regulated THMs approaching or exceeding the MCL. Although this free chlorine exposure prevented NDMA formation during chloramination, the ∼10 ng/L background NDMA formation in the tertiary effluent remained. Increasing the free chlorine exposure also increased the formation of unregulated halogenated DBP classes that may be significant contributors to the DBP-associated toxicity of the disinfected wastewater. The results indicate that sequential chlorination can be used to optimize the benefits of free chlorine (virus and NDMA control) and chloramine disinfection (THM, HAA, and coliform control).

The Modelling Approach for Predicting Coastal Pollutions using Rainfall Distributions over Different Land Use/Land Cover

Bae, H.-K., 2018. The modelling approach for predicting costal pollutions using rainfall distributions over different land use/land cover. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 11–15. Coconut Creek (Florida), ISSN 0749-0208.In this study, a modeling approach using rainfall distribution over different land use/land cover was developed and tested to predict coastal pollutions at the Aliso Beach, California, USA. Rainfall distributions over each land use/land cover of the study area, Aliso Creek Watershed, were calculated to use as input variables for the approach. In addition to rainfall distributions, streamflow and previous total coliform concentrations were also used as input variables. Six-hour. averages of rainfall and streamflow data were used since the approach estimated total coliform concentrations for every Six-hour. The estimations from the previous step, previous total coliform concentration, were used for last input variable if observation data were not available since total coliform concentrations were measured once every three days. Six different model scenarios were tested mainly focusing on rainfall events. As the model scenarios became more complicated, better estimations were shown. The approach showed the possibilities for finer time scale prediction, such as 1 hr. or less time scale or even real-time predictions, since precipitation and streamflow can be available for finer time scale and estimated previous concentrations would be used if observation data were not available.

Microbiological quality and antimicrobial resistance characterization of Salmonella spp. in fresh milk value chains in Ghana

Consumer perception of poor hygiene of fresh milk products is a major barrier to promotion of milk consumption as an intervention to alleviate the burden of malnutrition in Ghana. Fresh milk is retailed raw, boiled, or processed into unfermented cheese and spontaneously fermented products in unlicensed outlets. In this study, we have determined microbiological quality of informally retailed fresh milk products and characterized the genomic diversity and antimicrobial resistance (AMR) patterns of non-typhoidal Salmonella (NTS) in implicated products.A total of 159 common dairy products were purchased from five traditional milk markets in Accra. Samples were analysed for concentrations of aerobic bacteria, total and fecal coliforms, Escherichia coli, staphylococci, lactic acid bacteria and yeast and moulds. The presence of Salmonella, E. coli O157:H7, Listeria monocytogenes and Staphylococcus aureus were determined. AMR of Salmonella against 18 antibiotics was experimentally determined. Genome sequencing of 19 Salmonella isolates allowed determination of serovars, antigenic profiles, prediction of AMR genes in silico and inference of phylogenetic relatedness between strains.Raw and heat-treated milk did not differ significantly in overall bacterial quality (P = 0.851). E. coli O157:H7 and Staphylococcus aureus were present in 34.3% and 12.9% of dairy products respectively. Multidrug resistant (MDR) Salmonella enterica serovars Muenster and Legon were identified in 11.8% and 5.9% of unfermented cheese samples respectively. Pan genome analysis revealed a total of 3712 core genes. All Salmonella strains were resistant to Trimethoprim/Sulfamethoxazole, Cefoxitin, Cefuroxime Axetil and Cefuroxime. Resistance to Chloramphenicol (18%) and Ciprofloxacin (100%), which are first line antibiotics used in treatment of NTS bacteremia in Ghana, was evident. AMR was attributed to presence and/or mutations in the following genes: golS, sdiA for cephalosporins, aac(6′)-Iy, ant(9) for aminoglycosides, mdtK, gyrA, gyrB, parC, parE for quinolones and cat1, cat4 for phenicols. Phylogenetic analysis based on accessory genes clustered S. Legon strains separately from the S. Muenster strains. These strains were from different markets suggesting local circulation of related strains.Our study justifies consumer resistance to consumption of unripened soft cheese without further lethal heat treatment, and provides evidence that supports the Ghana Health Service recommendation for use of 3rd generation cephalosporins for the treatment of MDR NTS infections.

Tempo-spatial controls of total coliform and E. coli contamination in a subtropical hilly agricultural catchment

Waterborne microbial pollution remains poorly understood in developing countries, especially in rural areas. The transport of point (e.g. untreated domestic wastewater) and non-point sources of fecal bacteria such as Total coliform (TC) and Escherichia coli (E. coli) and their spatial and temporal patterns were identified in a typical small agricultural catchment in a hilly area of subtropical China. Over the sampling area, 460 water samples from 24 sites were collected during a period of 12 months, and a remediation option using an existing ecological ditch was evaluated. The results showed that 70% surface water samples exceeded the guideline of 1000 TC MPN 100 ml−1 in the catchment. Also, 90% of groundwater samples exceeded the guideline of 10 MPN E. coli 100 ml−1 for safe drinking water. Higher concentrations of TC and E. coli occurred both in the warm and rainy season in surface water and groundwater. TC and E. coli concentrations in surface water tributaries and groundwater near residential areas were greater than those in downstream water bodies. A 300 m long vegetated ecological ditch greatly reduced average concentrations TC of 97.7% and E.coli of 99.5%. TC and E. coli concentrations were significantly correlated with electrical conductivity and turbidity, both in surface water and groundwater, indicating that mixtures of organic colloids and sediment were the most important transport vector for pathogens. However, temperature only showed a controlling effect on bacteria concentration in groundwater in this particular catchment. The current research could help predict microbial risks and establish integrated management strategy to improve water quality in the hilly agricultural catchments in the subtropical region.

Decay rate of virus and faecal indicator bacteria (FIB) in seawater and the concentration of FIBs in different wastewater systems

Information about the concentration, growth and decay rates of enteric microorganisms in different wastewater systems and water bodies is crucial for quantitative microbial risk assessment (QMRA). In general, there is little information about this and in particular about the decay rates of faecal bacteria and viruses at different depths of the marine environment where many wastewater treatment plants discharge their effluent. This study was designed to investigate the concentration of faecal indicator bacteria (FIB) in different types of wastewater, the potential for growth of FIB in greywater, and the decay rates of FIB and pathogenic viruses in seawater samples from different depths. The intent of this work was to mimic summer water quality. Average concentrations of total coliforms (TC), Escherichia coli (E. coli) and intestinal enterococci (IE) (log10 per 100 ml) were 7.2, 6.7 and 6.1 in blackwater; 6.7, 6.1 and 3.8 in greywater; and 6.8, 6.6 and 5.2 in municipal wastewater, respectively. The numbers of TC and E. coli increased when greywater was stored for 24 h at 20 °C but decreased after 96 h. No growth of IE was observed in the greywater. The decay rate experiment showed that viruses and FIB were inactivated relatively rapidly at 20 °C in seawater collected from 1 m depth, while a slow inactivation was observed at 4 °C in seawater collected from 60 m depth, with a significant difference in decay rates (p < .05). Our results suggest that temperature and biological activity may be important factors for the self-purification capacity when wastewater containing faecal bacteria and viruses is discharged to coastal water, and these varying decay rates could be important in risk assessments.

Hygienic and Sanitary Conditions of Eggs Commercialized in Town Fairs and Markets

High nutritional content coupled with low cost and ease of purchase justifies the frequent use of chicken eggs. Even with technological innovations in the production, storage, and distribution of eggs, food poisoning continues to occur. Therefore, in the present study, we 1) evaluated the microbiological profile and the hygienic and sanitary quality of eggs commercialized in town fairs and markets and 2) verified whether there is any correlation between microbiological results and commercialization conditions. Thirty-six samples were collected from six municipalities in the region of Recôncavo from Bahia, Brazil. The hygienic and sanitary conditions were analyzed by quantifying the total coliforms, E. coli, mesophilic and psychrotrophic microorganisms, molds, and yeasts, and by the presence of Salmonella sp. The observational analysis showed that 91% and 68% of the samples in town fairs and markets, respectively, did not comply with the requirements of the current Brazilian legislation. There was no significant difference in the microbiological profile among samples from the fairs and markets. Several samples presented relevant significant values, indicating inadequate hygienic conditions and fecal contamination. Salmonella sp. was found in one sample. There was co-relationship between microorganism count and the variables “external dirt”, “external stains”, and “closeness to other products”, with high concentrations of total coliforms and E. coli in the non-conforming samples. Although no limits exist for mold and yeast counts, the presence of fungi makes the product unfit for consumption. Thus, the commercialization of eggs would benefit from more attention and supervision by the relevant authorities.

Surfing safe waves: integration of water quality modelling in the evaluation of potential health risks

Surfing is becoming an important asset for local development, despite engaging water quality concerns is often limited to bathing season - thus, a tool for decision support is required to yearly forecast the water quality, in order to minimise health risks and support water management decisions. The QUAL2E model was used on a watershed, in Peniche, a coastal city in Portugal. This study area was chosen due to complaints related to the water quality by the local surfing community. Results returned a total coliform concentration of 1,500 MPN/100 mL, with pig farming effluents being the major contamination source. These results constitute evidence that surfing here may represent a health risk - as winter months are more favourable to wave sports. Therefore, it would be of the uttermost importance to improve monitoring and mitigate the potential health risk. This should include a more profound analysis of the contribution of diffuse sources and to extend the current bathing season monitoring scheme during winter times.

Assessing social vulnerability to biophysical hazards in the Kumasi metropolis, Ghana

This study assesses social vulnerability to hazards by analyzing the nature of biophysical hazards, and the characteristics of exposures, susceptibilities and adaptive capacities in Kumasi. A mixed method approach was used to collect primary data from farms and nearby markets. Water, soil, and plant samples were collected and tested for total coliforms and cadmium. Primary dataset was also collected from farmers and vendors using structured interview guide and from key informants through in-depth interviews. The analysis shows that several pressures residing within the coupled social-ecological system are threats to the health and livelihood of the farmers and vendors. The concentration of cadmium and total coliform in irrigation water, soil, and plants exceeded the WHO/FAO acceptable standards. Bio-toxins in plants were also found to be potentially high. However, the degree of exposure to these stressors and the strength of response and adaptive capacities were determined to be dependent on position within the urban agriculture value chain, type of plant, and socio-demographic characteristics. The study concludes that pollution of irrigation water, soil, and plant is an issue of environmental concern in the urban agriculture system and requires concerted efforts of all stakeholders to address. It is recommended that there should be frequent monitoring of the quality of irrigation water, soil, and produce from urban farms and markets to assess their physical, chemical, and microbial properties and possibly initiate remedial measures where necessary. Government policies must also focus on building the resilience of urban farmers and vendors to reduce their vulnerability to biophysical hazards.

The Quality of Water of the Downstream of the Siak River, Riau Province, Based on Tidal Condition

The quality of water in a river is affected by its natural condition and pollutant input originated from activities conducted around the river. In the Siak river, however, the black water effect influences thedistribution of the pollutant in general. To understand the quality of water in the black water affected by an area, a study was conducted from December 2015 to July 2016. The water was sampled during lowand high tides, in 8 sampling sites that were distributed along the river, from the mouth of the river in Siak Sri Indrapura Regency to upstream in Palas Village, Kampar Regency (around 180 km from the mouth ofthe river). The results showed that in the downstream of the Siak river, the quality of water during the low and high tides was worse than the 3rd Class Water Quality Standard issued by the Government Regulation (GR No. 82 / 2001) except for the concentration of nitrate, total coliform, Hg, oil and fat. The BOD was 14-39.2 mg/L (the high tide) and 17-45.6 mg/L (the low tide), COD was 51.76-80.62 mg/L (thehigh tide) and 51.76-69.12 mg/L (the low tide), NH3-N was 0.03-1.09 mg/L (the high tide) and 0.03-0.92 mg/L (the low tide), while the NO2-N was 0.13-0.17 mg/L (the high tide) and 0.13-0.22 mg/L (the low tide). Based on the Storet Index, the water of the downstream in the Siak river during the low and the high tide can be categorized as heavily polluted (score -52 to -70), and it tends to decline during the high tide.

Instream coliform gradients in the Holtemme, a small headwater stream in the Elbe River Basin, Northern Germany

The Holtemme is a small headwater stream in North Germany’s Elbe River Basin. According to German and European legislation, hygienic monitoring is not mandatory for such water bodies which are neither drinking water sources nor categorized as bathing waters. Consequently, relatively little is known about the occurrence of–potentially pathogenic–bacteria and viruses in Germany’s streams and rivers. The Holtemme was selected for a case study because it is relatively well monitored for both chemical water quality and aquatic ecology, but not for hygiene. Originating in the mountains of Harz Nature Park, the 47 km long Holtemme is characterized by a strong longitudinal gradient in chemical water quality, which is related to different land uses and the influx of treated wastewater from two urban areas (Wernigerode and Halberstadt). Waste water loads received by the Holtemme are comparatively high when compared to similarly small streams. In 2015, total coliform concentrations between more than 200 and 77,010 bacteria per 100 mL, and fecal coliform concentrations between 5 and 24,060 bacteria per 100 mL were observed in the Holtemme’s main channel. The highest concentrations were typically found below the outlets of the two wastewater treatment plants. The treated wastewater contained total and fecal coliform concentrations of up to 200,500 and 83,100 per 100 mL, respectively; however, there were significant temporal variations. While the observed concentrations are unproblematic from a legal perspective (because no maximum permissible limits are defined for streams in Germany), they would exceed the tolerable limits for bathing waters in the EU, indicating moderate to critical pollution limits.

Daily prediction of total coliform concentrations using artificial neural networks

Current water quality monitoring systems depend on the analysis of in situ grab samples. This is both cost- and labor-intensive, which makes it difficult to conduct daily monitoring tests. One possible way of overcoming this problem is to use a modeling approach. This paper describes the use of an artificial neural network, Self-organizing Linear Output (SOLO), as a modeling approach to predict total coliform concentrations from rainfall and streamflow data. Six different input scenarios are tested to check the efficiency of the SOLO approach, and the results show that the prediction of total coliform concentrations is possible if rainfall events occur. However, poor estimation results are obtained when there is no rain. The model performance improves slightly during periods of no rain if streamflow data are incorporated into the input. However, the model requires more input variables for no-rain periods, because the streamflow data do not enable observed variations to be fully predicted.

Assessment of Physicochemical and Bacteriological Quality of Different Surface Water Samples of Tangail District, Bangladesh

Surface water, a vital element of ecosystem must be hygienic, but unfortunately the pollution of this water is now an alarming problem. The present work deals with the assessment of physicochemical and bacteriological profile of several untreated surface water sources to ensure its suitability for using domestic purposes and drinking along with the impact of bacterial contaminated water on public health and antibiotic resistance pattern of these bacteria. The samples were collected from twenty sampling point (13 ponds, 4 lakes, 2 rivers and one canal) of Tangail District from January 2017 to July 2017. To understand the seasonal variation, water samples were measured in two month; February (dry season) and June (wet season). Most of the water sampling points were polluted by dumping of waste, cattle wash and were not suitable for the drinking or other domestic purposes. Obtained results showed that water of the study area is slightly alkaline, no remarkable variation in the temperature of the water in both seasons and DO of all the sampling station were lower than standard limit during February. The mean concentration (M.C.) of total Coliform were 4 × 1022 cfu/100ml and 4.5 × 1018 cfu/100ml at February and June respectively and all the sampling point were contaminated with fecal coliform. Other pathogenic bacteria, E. coli (M.C: 1.1 × 1011 cfu/100ml at February and M.C: 2.2 × 107 cfu/100ml at June), Salmonella spp. (M.C: 1.1 × 105 cfu/100ml at February and M.C: 3.4 × 105 cfu/100ml at June), Shigella spp. (M.C: 8 × 104 cfu/100ml at February and M.C: 3.4 × 107 cfu/100ml at June), Vibrio spp. (M.C: 8.6 × 105 cfu/100ml at February and M.C: 1.1 × 108 cfu/100ml at June) were isolated from several of the investigated water sources. The total counts of these pathogenic bacteria exceeded the acceptable limit during both season and also showed resistance against a broad range of commercially available antibiotics. People who were using these water frequently suffering from various water borne diseases. These untreated water sources pose a major threat to the public health and therefore with need for exigent intervention by government.

An assessment of the impacts of Gypsum mining on water quality in Kajiado County, Kenya

In the recent past, Kenya has witnessed increased activity in the extractive industry targeting minerals such as titanium, gypsum and gold to name a few. Mining activities are a potentially important contributor to water contamination. Discussions in the literature on impacts of gypsum mining on water quality are not conclusive because they tend to be site specific and lacking in details. This study sought to establish the impacts of gypsum extraction activities on water quality in Kajiado. The study adopted the descriptive/diagnostic design. Questionnaires and interview schedules were used to collect data from a sample of 95 respondents and key informants selected through Simple Random Sampling, Stratified Random Sampling and Purposeful Sampling. The APHA (1999) protocol was followed in the collection, storage and analysis of samples. Results indicated significant indirect influence of mining activities on water quality parameters. Even though chemical contamination was insignificant, the bacteriological concentration indirectly arising from gypsum mining was higher than WHO (2006) guide values and therefore exposed the public to waterborne diseases. The mean total coliform concentration in the surface water samples was 555/100 ml, with a minimum of 75 and maximum of 2400. There was no significant difference in the disease burden for children aged below 5 years and the rest of the population (p ≤ 0.206). The study recommends awareness creation on safe use of mine pond water.

Environmental Geochemistry and Heavy Metal Assessment in Soils, Surface and Groundwater from Eastern Niger-Delta, Nigeria using Multivariate Pollution Indices

In recent times, there have been increasing interests regarding heavy metal contaminations in the environments, apparently due to their toxicity and perceived persistency within the aquatic systems. Land and water are precious natural resources on which rely the sustainability of agriculture, industrialization and the civilization of mankind. They have been subjected to severe exploitation and contamination due to anthropogenic activities resulting from industrial effluent, refuse dumps, gas flaring, oil spillage and petroleum refining leading to the release of heavy metals into the environment. The results of the analyses indicate a low pH (3.84 – 7.74) and high concentrations of electrical conductivity (28.00 – 752.00), chloride (12.00 – 721.00) and heavy metals in the decreasing order of: Fe &gt; Ni &gt; Cu &gt; Zn &gt; Mn &gt; Cd &gt; V &gt; Co &gt; Pb &gt; Cr &gt; As &gt; Hg. The heavy metal pollution index revealed that the metal pollution in the soil and water ranged from slightly polluted to very highly polluted. The poor sanitary condition coupled with the high degree environmental abuses in terms of oil spillage, gas flaring and industrial effluent in the area are responsible for the low pH, wide range in the concentration of EC, TDS, Chloride, E.coli, total coliform and heavy metals in the soil and water system in the area. Good sanitation, use of welllined soakaway, treatment of industrial effluent before discharge and putting an end to gas flaring and oil spills are advocated. The use of environmentally friendly techniques such as bioremediation and phytoremediation in remediating the contaminated soil and water in the area is recommended.

Handwashing, but how? Microbial effectiveness of existing handwashing practices in high-density suburbs of Harare, Zimbabwe.

Consistent domestic hand hygiene can reduce diarrhea-related morbidity and mortality and the spread of other communicable diseases. However, it remains uncertain which technique of handwashing is most effective and practicable during everyday life. The goal of this study is to determine how the handwashing technique, as performed in the daily life by the participants of this case study in Harare, Zimbabwe, influences microbial handwashing effectiveness. Handwashing technique of 173 primary caregivers was observed in their homes and hand rinse samples were collected before and after handwashing. Samples were analyzed for Escherichia coli and total coliform concentrations. Generalized linear models were used to predict fecal hand contamination after washing from observed handwashing technique. Cleaning under fingernails, scrubbing the fingertips, using soap, and drying hands through rubbing on clothes or a clean towel statistically significantly reduced E coli contamination of hands after washing. Tap use, scrubbing fingertips, and rubbing hands on clothes to dry them statistically significantly reduced total coliform contamination. Recommendations for effective and practicable domestic handwashing in Harare, Zimbabwe, should include performing specific handscrubbing steps (ie, cleaning under the fingernails and rubbing the fingertips), and soap and tap use. This calls for further research to develop behavior change interventions that explicitly promote effective handwashing technique at critical times.

Qualitative characteristics of water resulting from the introduction of Eucalyptus silviculture in Pampa biome, RS

ABSTRACT This study aimed to present the effect on surface water quality of the introduction of eucalyptus forestry in areas that were traditionally used for extensive cattle farming in the Pampa biome, by comparing two paired watersheds located in the municipality of Rosário do Sul, one of them used for forestry and the other in an anthropized natural grassland condition in the Pampa biome. For this purpose, every fifteen days the following parameters were collected and analyzed in two watersheds with different land uses (watershed with grassland and extensive livestock farming – GW and watershed with Eucalyptus - EW) between the months of August 2011 and August 2012: pH, EC, temperature, turbidity and concentrations of SO42-, K+, Ca2+, Mg2+, Cl-, BOD5,20, SS, DS, alkalinity, total coliforms and Escherichia coli. Water quality and land use parameters averages were compared using the t-Test to account for the land use and seasonality. It was concluded that the introduction of forestry activity together with the areas of environmental protection required by the Brazilian legislation (Permanent Preservation Areas - PPA plus Legal Reserve - LR), contributed to the increased concentrations of conductivity, dissolved solids, alkalinity and calcium, and the decreased concentrations of total coliforms and Escherichia coli.

A survey of heterotrophic bacteria and coliforms in the water of old and new distribution networks

Controlling the microbiological quality of water is important for its uses. Microbiological requirements of drinking water ensure the absence of coliforms, but may indicate the potential presence of other potentially pathogenic microorganisms and viruses of fecal origin. A total of 36 water samples, representing the drinking water of the whole city of Aradan, Semnan, Iran, were randomly collected from the old and new distribution systems of Aradan from December 2014 to June 2015.The hetroterophic plate count (HPC), coliform, residual chlorine, and pH of the samples were measured. Heterotrophic bacteria were measure using R2A and nutrients agar culture media, and the spread plate count method was used to determine HPC. Average concentration of total coliform in the old distribution network ( 13⁄84 100 ml ) was more than the new distribution network ( 9⁄42 100 ml ). The results of studying microbial load in the old and new distribution network showed that there is a significant difference between total coliforms in the two networks (P = 0.002). Moreover, the average concentration of heterotrophic bacteria in the old distribution network (1917.33 number/100 ml) was more than that in the new distribution network (14.57 number/100 ml). There was a significant difference between the average concentration of heterotrophic bacteria in the old and new distribution networks (P = 0.003). The effects of seasons and the age of the water network on coliform bacteria and heterotrophic bacteria were also studied. The concentrations of heterotrophic bacteria, total coliform, and fecal coliforms were higher in the old distribution network in comparison to that in the new distribution network.

Microbial contamination along the main open wastewater and storm water channel of Hanoi, Vietnam, and potential health risks for urban farmers

The use of wastewater in agriculture and aquaculture has a long tradition throughout Asia. For example, in Hanoi, it creates important livelihood opportunities for >500,000 farmers in peri-urban communities. Discharge of domestic effluents pollute the water streams with potential pathogenic organisms posing a public health threat to farmers and consumers of wastewater-fed foodstuff. We determined the effectiveness of Hanoi's wastewater conveyance system, placing particular emphasis on the quality of wastewater used in agriculture and aquaculture. Between April and June 2014, a total of 216 water samples were obtained from 24 sampling points and the concentrations of total coliforms (TC), Escherichia coli, Salmonella spp. and helminth eggs determined. Despite applied wastewater treatment, agricultural field irrigation water was heavily contaminated with TC (1.3×107colony forming unit (CFU)/100mL), E. coli (1.1×106CFU/100mL) and Salmonella spp. (108 most probable number (MPN)/100mL). These values are 110-fold above Vietnamese discharge limits for restricted agriculture and 260-fold above the World Health Organization (WHO)'s tolerable safety limits for unrestricted agriculture. Mean helminth egg concentrations were below WHO tolerable levels in all study systems (<1egg/L). Hence, elevated levels of bacterial contamination, but not helminth infections, pose a major health risk for farmers and consumers of wastewater fed-products. We propose a set of control measures that might protect the health of exposed population groups without compromising current urban farming activities. This study presents an important example for sanitation safety planning in a rapidly expanding Asian city and can guide public and private entities working towards Sustainable Development Goal target 6.3, that is to improve water quality by reducing pollution, halving the proportion of untreated wastewater and increasing recycling and safe reuse globally.

A case study of the conversion of grey water to a flush water source in a Turkish student residence hall

A case study of the conversion to grey water to a flush water source in a student residence hall of the Turkish megacity Istanbul is presented. Grey water from bathtubs/showers and washbasins is treated and reused for flushing toilets. Raw and membrane bio-reactor (MBR) treated grey water quality was monitored throughout one academic year using parameters to characterize organic matter (COD/BOD), suspended solids (TSS/VSS), nutrients (N/P) and microbiological indicators (total/fecal coliform, Escherichia coli, Enterococcus). For raw grey water, all mean concentrations are below the characteristic concentrations for weak conventional domestic wastewater in terms of physicochemical parameters. However, total coliform concentrations were 7 logs, which is compatible with weak/intermediate conventional domestic wastewater and the mean concentration of fecal coliforms was 6 logs, corresponding to intermediate/strong conventional domestic wastewater. Results of this work revealed that organic matter and microbiological indicators were the important pollutants for this specific grey water. After treatment in an MBR system, grey water quality complied with standards given for reuse as flush water. The student residence hall was a successful example of conversion to grey water as a flush water source. As such, 25% of the wastewater could be revaluated and 25% of the regular daily water supply could be saved.

Bases limnologicas para la gestion de los lagos urbanos de Concepcion, Chile

Morphological, physical and chemical characteristics of urban lakes of Conception were studied. The results indicate that these lakes are in an advanced process of eutrophication caused by excessive anthropogenic nutrient loads (mainly phosphorus and nitrogen). Furthermore, high concentrations of faecal and total coliforms in the water column and heavy metals in the sediments of these lakes were recorded. The principal component analyses showed that total phosphorus, ammonia, pH, conductivity, transparency and chlorophylla, are the variables that best explain the water conditions of all the lakes studied. It is recommended to orientate the lake management actions to decrease total phosphorus. Considering the particular situation of each lake, a series of complementary measures for reversing the current situation should be applied. This study provides new limnological information for the decision-making process focussed on the recovery of urban lakes of the City of Concepcion.