Conditioning treatments mitigate the levels of fecal pollution indicators in soil during land-application of sewage sludge

Sewage sludge is a major source of fecal pathogens in the environment,and its application to land can result in a significant release of these pathogens into the soil.While conditioning treatments are crucial for improving the dewatering process of sludge,their impact on the presence and behavior of fecal pathogens in soil remains unclear.This study aims to assess four extraction methods for recovering fecal pollution indicators from soil amended with unconditioned and conditioned sludge.The indicators include Escherichia coli(EC),human-specific HF183 Bacteroides(HF183),human adenovirus(HAdV),human BK polyomavirus(BKPyV),human JC polyomavirus(JCPyV),and cross-assembly phage(crAssphage).This study also examines how soil moisture content affects the decay of these fecal pollution indicators in soil amended with raw sludge and investigates the influence of conditioning treatments with cationic polyacrylamide(PAM),Fenton’s reagents,Fe[III]/CaO on their persistence in soil.The results indicated that the direct extraction method was the most effective and unbiased for recovering fecal pollution indicators from sludge-amended soil compared with the three elution-concentration methods.All fecal pollution indicators,except HAdV,remained stable under dry soil conditions,while high soil moisture content(48.39%‒53.14%)slowed the decay rates of these indicators.During the application of sludge to soil,effective control of fecal pollution indicators was observed,with JCPyV and HAdV becoming undetectable within a short period.The log reduction values of HF183,BKPyV,and crAssphage ranged from 0.1 to 2.8 logs after 30 d of cultivation.The application of conditioned sludge,especially Fenton’s reagent-conditioned sludge,resulted in a reduction in human fecal contamination in the receiving soil.Therefore,implementing appropriate conditioning methods,such as using Fenton’s reagent,can effectively mitigate the health risks associated with fecal pathogens.

Validation of Bacteroidales-based microbial source tracking markers for pig fecal pollution and their application in two rivers of North China

In China,pig feces is the predominant source of excrement produced b y animal husbandry.Improper use or direct discharge of pig feces can result in contamination of natural water systems.Microbial source tracking(MST)technology can identify the sources of fecal pollution in environmental water,and contribute to the management of pig fecal pollution by local environmental protection agencies.However,the accuracy of such assays can be context-dependent,and they have not been comprehensively evaluated under Chinese conditions.We aimed to compare the performance of five previously reported nig-specific MST assays(PF,Pig-Bac 1 STBR,Pig-Bac2 SYBR,Pig-1-Bac TaqMan,and Pig-2-Bac TaqMan,which are based on Bacteroidales 16S rRNA gene markers)and apply them in two rivers of North China.We collected a total of 173 fecal samples from pigs,cows,goats,chickens,humans,and horses across China.The PF assay optimized in this study showed outstanding qualitative performance and achieved 100%specificity and sensitivity.However,the two SYBR green qPCR assays(Pig-Bac1 SYBR and Pig-Bac2 SYBR)cross-reacted with most non-pig fecal samples.In contrast,both the Pig-l-Bac TaqMan and Pig-2-Bacr TaqMan assays gave 100%specificity and sensitivity.Of these,the Pig-2-Bac TaqMan assay showed higher reproducibility.Our results regarding the specificity of these pig-specific MST assays differ from those reported in Thailand,Japan,and America.Using the PF and Pig-2-Bac TaqMan assays,a field test comparing the levels of pig fecal pollution in rivers near a pig farm before and after comprehensive environmental pollution governance indicated that pig fecal pollution was effectively controlled at this location.

Investigation of fecal coliform and typical enteric virus in representative beaches of China

Through investigating ten recreational marine beaches in China, we aimed to detect the occurrence of human enteric viruses in coastal bathing beaches and find a correlationship, if any, between the presence of enteric viruses in surface seawater and the concentrations of fecal coliforms, the conventional indicator of fecal pollution. In this study, twenty seawater samples were assayed for fecal coliforms and human pathogenic enteric viruses （hepatitis A viruses, rotaviruses, polioviruses） analysis. Enteric viruses were detected by RT-PCR, in 20 sample sites, 5%, 40%, 40% were positive for the presence of human hepatitis A viruses, rotaviruses, polioviruses, respectively. Seven of 20 sites are suffering from severe fecal contamination, based on traditional plate counts of fecal coliform outnumbering the established thresholds for recreation. Additionally, statistical analysis presented that no correlation was found between bacterial indicators and viruses in surface seawaters. The data confirmed that indicator bacteria in water are not reflective of the presence of enteric viruses in marine waters. Thus, current recreational water quality standards of both bacterial and viral indices should be reevaluated.

Influence of Rainfall, Discharge, Wave and Alongshore Transport on Microbiological Pollution in Southern California Coastal Beaches

The coastal zone is the significant environmental setting where ocean interfaces land. In addition, it is economically important because of its high residential, commercial and recreational values. Meanwhile, in the United States, public coastal areas are increasingly off-limits due to elevated levels of fecal pollution and other contaminants. This study investigates the effects of rainfall, discharge, wave, and alongshore transport on coastal FIB （fecal indicator bacteria） concentrations at adjacent beaches in Orange County, California, over three years＇ period from October 2001 to September 2004. In order to identify the dominant tempora land spatial patterns of fecal pollutions along the coastal beaches, Empirical Orthogonal Function analysis was utilized for the three-year measurements （n = 39,525） of FIB concentration data from 17 sampling stations. Through the data analysis and the empirical orthogonal function analysis, it was found that the dominant factor effecting coastal FIB concentration is precipitation event and consequent water discharge from Santa Ana River in the area. The Empirical Orthogonal Function analysis revealed the potential non-point FIB sources around northern part of Orange County beaches. In addition, this study confirmed the existing alongshore transport by wave-driven surf zone current and offshore tidal currents.

Prediction of Coastal Fecal Indicator Bacteria Concentrations Using Multivariate Data Analysis

The application of multivariate data analysis, a method for coping with multi-colinearity among independent variables in analyzing coastal water quality data, is presented. This study investigates the statistical regression modeling of FIB （fecal indicator bacteria） concentrations at the outlet of Talbert Marsh in Orange County, California. The multivariate data modeling utilized FIB and physical variables measurements （n = 5,580） collected during a series of longitudinal study of the Talbert Marsh. For the statistical prediction modeling in predicting the FIB concentrations at the outlet of the Talbert Marsh, multivariate analysis techniques such as PCR （principal components regression）, PLS （partial least-squares） regression and SVM （support vector machine） regression were adopted. Statistical modeling results suggest that the statistical modeling predictions are all fell within the reasonable range of actual measurement data. In addition, it is indicated that the accuracy of SVM regression for predicting FIB concentrations at the Talbert Marsh outlet is better than that of other models.

Decadal Trend of Coastal Water Quality in Orange County Beaches and Management Efficacy at Improving Public Health Protection

Historical fecal indicator bacteria measurements （n = 125,000; 10 years） in Orange County coastal zone, an interface with urban watershed that is one of the most developed areas in the United States and source of highly polluted runoff discharges, have been compiled and analyzed. During the period from 2000 to 2010, fecal indicator bacteria concentrations in Orange County Beaches progressively increased （poor water quality） in the first half of the decade and progressively decreased （improved water quality） during the last half of the decade. Among all physical, chemical and environmental factors, 59%-74% of the variability in the fecal indicator bacteria concentrations in the coastal zone records can be attributed to seasonal and interannual variability in local rainfall, implying that stormwater runoff from the surrounding urban watershed is a primary source of fecal pollution in Orange County Beaches. These results suggest that efforts to improve water quality in Orange County Beaches and protect beach-goers from pollution will likely have greater efficacy during wet weather periods than the rest of the year. In addition, this study identified the effect of alongshore surf zone current on fecal pollution caused by coastal waves. The data and analysis presented in this paper provide a framework for evaluating the longer period water quality trend in the coastal area, and elucidate Best-Management-Practices that can improve public health protection by managing coastal water quality compliance with standards.

Microbial Quality of Wastewater Used in Urban Truck Farming and Health Risks Issues in Developing Countries:Case Study of Ouagadougou in Burkina Faso

Urban truck farming in developing countries appears of great importance to overcome unemployment and poverty. However, the quality of wastewater used for such activity could expose populations to waterborne diseases. The microbial quality of wastewaters used for truck farming in Ouagadougou city, was examined for the presence of bacterial and parasitological fecal indicators during the dry-hot season (May) and the wet season (July) in 2012. The wastewaters of three water reservoirs and two canals intensively used for truck farming were analyzed throughout the study. These indicators were also monitored in waste stabilization ponds during wastewater treatment in 3 plants of the city. For all the selected sampling sites, the concentrations of microbial indicators in water were significantly higher in the dry-hot season compared to the wet one (p - 53,800 CFU/100ml for Escherichia coli, 8200 - 108,400 CFU/100ml for fecal coliforms, 650 - 45,000 CFU/100ml) for fecal streptococcus, and 0 - 2.4 eggs/l for helminthes during the study periods. For wastewater under treatment in waste stabilization ponds, significant microbial concentration drops (p 0.0001) in the range of 82% - 100%, 78% - 98%, 60% - 100% and 82% - 88%, respectively were recorded between the anaerobic and the maturation ponds. The later results highlighted that improving the refining performances of the waste stabilization ponds technology could help decreasing health risks related to wastewater reuse in urban agriculture for a sustainable development of cities in developing countries.

Development of a sensor for the detection of Escherichia coli in brackish waters

Monitoring of bacterial pathogens is important for marine environmental protection,because the presence of these microorganisms can be a serious risk for human health.For this reason,a portable sensor implemented as an electronic embedded system featuring disposable measurement cells was used to evaluate the ability and sensitivity of detection of Escherichia coli(E.coli)as an indicator of fecal pollution in transitional environments and a water sample added with E.coli(10^(2) CFU/mL)was assayed.The first result obtained from the laboratory experiment seems promising for the determination of E.coli in environmental samples,though further improvements will be needed for the field application of this sensor in marine and brackish waters.