Calibration of a Continuous Simulation Fecal Coliform Model Based on Historical Data Analysis

Since 1984, the major water reclamation plants discharging to the Chicago Waterway System (CWS) have not disinfected their effluents. The possible addition of disinfection at these plants is the subject of an ongoing use attainability analysis (UAA). For the UAA, Escherichia coli (E. coli) is used as the indicator of bacterial contamination. However, only a few years of E. coli data are available for the CWS and the treatment plants discharging to the CWS. Thus, it was decided to develop a model based on fecal coliforms for which more data are available and to develop a relation between fecal coliform and E. coli counts for the CWS. A 1:1 relation was found between fecal coliform and E. coli counts in the CWS by Limnotech (2004, written communication) as part of the UAA. In order to evaluate the effects of possible disinfection measures on fecal coliform and related E. coli counts in the CWS, a simple first-order fecal coliform decay model was added to the continuous-simulation flow-water quality model DUFLOW applied to the CWS system. Due to the limited amount (monthly samples) of measured fecal coliform concentration data for the CWS, a reasonable calibration of the model would have been difficult to achieve based on the traditional trial and error method. In this paper, a new concept of model parameter estimation based on historical data analysis and its application to model calibration is presented. The fecal coliform decay rate k was estimated for every reach of the CWS based on analysis of historical data (1990–2003) between each two consecutive sampling locations and the related travel time between these stations. The fecal coliform decay rate then was determined on the basis of many years (14 years, in this case) of monthly fecal coliform samples rather than the few monthly samples taken in a typical calibration period. The results obtained indicate that the calibration process was successful, and a good match between measured and simulated fecal coliform concentrations at almost all locations along the CWS is achieved with one model run for several multiple month periods in 1998, 1999, 2001, and 2002.     

Methods for Quantifying Lime Incorporation into Dewatered Sludge. I: Bench-Scale Evaluation

The addition of alkaline material (usually lime) to treated municipal sludge can be used to raise the pH to ≥ 12 and generate Class A or B biosolids. When lime is added to dewatered sludge, it must first be made into a slurry before the pH can be measured to demonstrate regulatory compliance. In this study, pH 12 was achieved in slurries prepared from lime-amended dewatered sludge, even when the lime was poorly incorporated and relatively high fecal coliform levels were detected. Thus, quantitative indicators of lime incorporation are needed to complement slurry pH measurements and ensure that sufficient contact occurs between lime and sludge particles to achieve adequate stabilization. In this study, the usefulness of several potential measures of lime incorporation—pH, CO2 consumption, distribution of calcium, fecal coliforms, NH3 and reduced sulfur compound production, and ATP—was systematically evaluated using a bench-scale system. Sludge pH and CO2 consumption were not influenced by the extent of lime incorporation. The distribution of calcium and fecal coliform levels appear to be useful measures of lime incorporation. NH3 and reduced sulfur compound emissions and ATP levels can also be used to assess lime incorporation provided recommended experimental techniques are used.     

Statistical Evaluation of Factors Affecting Indicator Bacteria in Urban Storm-Water Runoff

An urban watershed in Raleigh, North Carolina, was monitored for indicator bacteria during 20 rain events. Results showed elevated levels of E. coli, enterococci, and fecal coliform. Samples were compared based on seasonality and were found to be statistically different (p<0.05), with pairwise comparisons indicating significantly lower concentrations of E. coli and fecal coliform during the winter (p<0.05). Enterococci concentrations were substantially lower in the winter and fall, but no significant differences were found between seasons during pairwise comparisons (p<0.05). Correlation analyses showed multiple significant relationships between antecedent climate parameters, flow characteristics, and indicator bacteria concentrations. More detailed multiple linear regression yielded explanatory variables related to antecedent climate conditions. Variables were generally related to temperature and moisture conditions in the atmosphere and soil. The results of this study show indicator bacteria concentrations significantly vary based on season; however, this variability can partially be explained by antecedent climate data.     

Factors Affecting Inactivation Behavior in the Monochloramination Range

The effects of monochloramine application techniques, chlorine-to-ammonia-N (Cl:N) ratios, water matrices, and bacterial origins on fecal coliform bacteria inactivation behavior in the monochloramination range were studied in ammoniacal bacteria suspensions and wastewater samples containing either naturally occurring or reseeded laboratory-cultured fecal coliform bacteria. The time-dependent chlorine residual concentrations and the bacteria counts were measured. The inactivation behavior was strongly affected by the monochloramine application techniques and the initial chlorine and ammonia concentrations and ratios. When dosing free chlorine to the ammoniacal solution, a “two-stage” pattern that coupled initial inactivation by transitory free chlorine and extended inactivation by forming monochloramine was observed at a Cl:N ratio of 3:1, while, at a high initial ammonia concentration (20?mg/L), synergy without initial inactivation was found instead. The difference is explained with calculations of the free-chlorine CT values. The inactivation behavior of laboratory-cultured suspensions differed from that of wastewater effluents, which was primarily attributable to the variations in the water matrix, not to the bacterial origins. Conducting dose-response studies using autoclaved wastewater samples reseeded with field-isolated, laboratory-cultured bacteria was proposed as the solution.     

Pollutant Removal and Peak Flow Mitigation by a Bioretention Cell in Urban Charlotte, N.C.

Bioretention is a stormwater treatment practice that has gained popularity due to its aesthetics, potential to reduce flooding, and early documented improvements to stormwater quality. A bioretention cell in an urban setting was examined in Charlotte, N.C. from 2004 to 2006. Flow-weighted, composite water quality samples were collected for 23 events and analyzed for TKN, NH4-N, NO2-3-N, TP, TSS, BOD-5, Cu, Zn, Fe, and Pb. Grab samples were collected from 19 storms for fecal coliform and 14 events for Escherichia coli (E. coli). There were significant reductions (p<0.05) in the concentrations of TN, TKN, NH4-N, BOD-5, fecal coliform, E. Coli, TSS, Cu, Zn, and Pb. Iron concentrations significantly increased (p<0.05). NO2-3-N concentrations were essentially unchanged. Efficiency ratios for TN, TKN, NH4-N, TP, and TSS were 0.32, 0.44, 0.73, 0.31, and 0.60, respectively. Fecal coliform and E. coli efficiency ratios were 0.69 and 0.71, respectively. Efficiency ratios for Zn, Cu, and Pb were 0.77, 0.54, and 0.31, respectively. Concentrations of Fe increased by 330%. The peak outflow of the bioretention cell for 16 storms with less than 42?mm of rainfall was at least 96.5% less than the peak inflow, with a mean peak flow reduction being 99%. These results indicated that in an urban environment, bioretention systems can reduce concentrations of most target pollutants, including pathogenic bacteria indicator species. Additionally, bioretention can effectively reduce peak runoff from small to midsize storm events.     

Total Coliform Survival Characteristics in Frozen Soils

Survival characteristics of total coliform bacteria in soil samples, with different moisture contents (24–49%) and at different temperatures (from ?28 to 20°C), were studied. The study showed that a significant fraction of coliform bacteria survive for more than six months in soil at subfreezing temperatures. Survival of total coliform bacteria at subfreezing temperatures decreased with an increase in moisture content and an increase in temperature. For 24% moisture, approximately 66% of the coliforms survived at ?28°C after 170 days, whereas less than 0.1% survived at room temperature. First-order die-off rate constants varied between 0.041/day at room temperature and 0.002/day from ?15 to ?28°C (for 24% moisture). The impact of temperature on the die-off rate constant was described by the Arrhenius equation. The high survival at subfreezing temperatures indicates that fecal bacteria at honeybucket dumpsites may survive throughout the Alaskan winter which may lead to the contamination of water sources during spring thaw.     

Sources of Fecal Pollution in Virginia’s Blackwater River

Sources of fecal pollution in the Blackwater River in south-central Virginia were identified. The study area encompassed intensive dairy and beef farming, abundant wildlife populations, homes with on-site septic systems, and four stream segments listed as impaired due to high-fecal coliform concentrations. A library of antibiotic resistance profiles was developed for 1,451 Enterococcus isolates from human, wildlife, and livestock. A discriminant analysis model was used to classify the isolates by source and calculate rates of correct classification (RCC) for each source. RCCs for the known source library were 82.3% for human, 86.2% for livestock, and 87.4% for wildlife. Profiles were determined for Enterococcus isolates from stream samples collected periodically from August 1999 to August 2001 (a total of 8,542 isolates) and compared against the known source library. Livestock contributed the highest percentage of isolates (47.6%) in the four segments studied, followed by wildlife (29.1%), and human (24.9%). The results indicate that reducing fecal pollution will require consideration of all three source categories. The results from this research are being used to develop total maximum daily load project allocations for fecal coliforms in the Blackwater River.     

Indicator Bacteria Removal in Storm-Water Best Management Practices in Charlotte, North Carolina

Water quality degradation due to pathogen pollution is a major concern in the United States. Storm-water runoff is an important contributor to the transport of indicator bacteria from urbanized watersheds to nearby surface waters. With total maximum daily loads being established to reduce the export of indicator bacteria to surface waters, storm-water best management practices (BMPs) may be an important tool in treating indicator bacteria in runoff. However, the ability of these systems to remove indicator bacteria is not well established. A study in Charlotte, N.C., monitored nine storm-water BMPs (one wet pond, two storm-water wetlands, two dry detention basins, one bioretention area, and three proprietary devices) for fecal coliform and Escherichia coli (E. coli). A wet pond, two wetlands, a bioretention area, and a proprietary device all removed fecal coliform with an efficiency higher than 50%; however, only the wetlands and bioretention area had significantly different influent and effluent concentrations (p<0.05). For E. coli, only one of the wetlands and the bioretention area provided a concentration reduction greater than 50%, both of which had a significant difference in influent and effluent concentrations (p<0.05). Only one of the nine BMPs had a geometric mean effluent concentration of fecal coliform lower than the U.S. EPA target value, while four of the nine BMPs had geometric mean effluent concentrations lower than the U.S. EPA standard for E. coli. This study showed that some BMPs may be useful for treatment of indicator bacteria; however, other BMPs did not perform well. Because wet, nutrient-rich environments exist in many storm-water BMPs, there is a potential for indicator bacteria to persist in these systems.     

Anchoring of c-myc on nuclear matrix proteins in process of mouse thymic T lymphocyte proliferation induced by ConA

Epidemiologic investigations of the Latin America cholera epidemic have repeatedly implicated untreated drinking water and water touched by hands during storage as important vehicles for disease transmission. To prevent such transmission, we provided a new narrow-mouthed, plastic, water storage vessel and 5% calcium hypochlorite solution for home disinfection of stored water to a Bolivian Aymara Indian community at risk for cholera. We evaluated acceptance of this intervention and its effect on water quality. Each of 42 families in the study obtained water from a household well; fecal coliform bacteria were found in water from 39 (93%) of 42 wells and 33 (79%) of 42 usual water storage vessels. One group of families received the special vessels and chlorine (group A), a second received only the special vessels (group B), and a third served as a control group (group C). Water samples collected every three weeks from group A special vessels had lower geometric mean fecal coliform colony counts (P < 0.0001) and lower geometric mean Escherichia coli colony counts (P < 0.0001) than water from group B or C vessels. Adequate levels of free chlorine persisted in these vessels for at least 5 hr. The special vessels and chlorine solution were well accepted and continued to be used for at least six months. Use of the vessel and chlorine solution produced drinking water from nonpotable sources that met World Health Organization standards for microbiologic quality.     

Aerobic Thermophilic and Anaerobic Mesophilic Treatment of Sludge

The objective of this research was to investigate the effectiveness of aerobic thermophilic treatment in enhancing conventional anaerobic mesophilic digestion in terms of pathogen reduction. vector attraction reduction, volatile solids (VS) reduction, gas production, and product sludge dewaterability. Lab-scale two-stage experiments were conducted with the aerobic thermophilic stage as pretreatment (AerTAnM) or as posttreatment (AnMAerT) to mesophilic anaerobic digestion. The lab-scale AerTAnM and AnMAerT systems were operated at system sludge residence times (SRTs) of 15 and 15.5 days, thermophilic reactor temperature = 62°C, and mesophilic reactor temperature = 37°C. The control anaerobic digester was operated at a system SRT of 15 and 15.5 days and temperature = 37°C. The AerTAnM and AnMAerT systems and control anaerobic digester operated at a system SRT of 15 days were able to achieve VS reductions of >38% (Class A sludge vector attraction reduction requirement). The VS reductions by the AerTAnM and AnMAerT systems (～65%) were higher than the VS reduction in the control (～51%) by 14%. The AerTAnM and AnMAerT systems reduced fecal coliform density in the feed sludge from 108 most probable number (MPN) per gram of total solids (TS) to <103 MPN∕g TS (Class A sludge fecal coliform density limit), whereas the control reduced the same feed sludge fecal coliform density to about 106 MPN∕g TS. The AerTAnM and AnMAerT systems and control can reduce Salmonella density in the feed sludge from 5 to 12 MPN∕4 g TS to <1 MPN∕4 g TS. Average methane gas production by the AerTAnM system anaerobic mesophilic digester (0.61 m3∕kg VS destroyed) was higher than those of the AnMAerT system (0.50 m3∕kg VS destroyed) and control (0.52 m3∕kg VS destroyed) anaerobic mesophilic digesters. Average H2S content of the AerTAnM [133 ppm volume-to-volume ratio (v∕v)] system anaerobic thermophilic digester gas was significantly lower than those in gas from the AnMAerT system (249 ppm v∕v) and control (269 ppm v∕v) anaerobic mesophilic digesters. The dewaterabilities of the product sludge (measured as time-to-filter, s) from the AerTAnM system (237 s) and AnMAerT system (203 s) were significantly better than that of the product sludge from the control (346 s).     

Case Study of a Marine Filter Curtain System for Coliform Reduction at a Public Beach

A floating marine filter curtain system (boom) was placed around a tidal beach on Long Island Sound to reduce coliform levels following storm events. Coliform data were collected inside and outside the boom over a three-year period. The results showed a 93% reduction in total coliforms and a 73% reduction in fecal coliforms, based on a comparison of the medians. Exceedences of the applicable water quality standards were reduced by 98% for total coliforms, and 81% for fecal coliforms. The method by which the boom actually reduces bacteria levels is thought to be a combination of filtration of solids, and the alteration of hydraulic conditions at the beach.     

Effect of In-Lake Water Quality on Pollutant Removal in Two Ponds

An extensive field study examined pollutant removal in two regional wet detention ponds near High Point, N.C. Substantial differences in influent pollutant concentrations between the ponds caused significant differences in pond water quality and pollutant removal efficiency. In Davis Pond, influent fecal coliform and nutrient concentrations were high because of several large dairy farms in the watershed, resulting in hypereutrophic conditions as evidenced by high chlorophyll-a concentrations, high midday pH values and supersaturated midday oxygen concentrations. In Piedmont Pond, influent fecal coliform and nutrient concentrations were much lower, resulting in mesotrophic to slightly eutrophic conditions. Both ponds thermally stratified and developed an anaerobic hypolimnion. In Davis Pond, annual pollutant removal efficiencies for total suspended solids, volatile suspended solids, total organic carbon, total phosphorus, dissolved phosphorus, nitrate∕nitrite, total ammonia nitrogen, and total nitrogen were 56%, 32%, 15%, 41%, 54%, 16%, 2%, and 11%, respectively. In Piedmont Pond, annual pollutant removal efficiencies were 20%, 30%, 27%, 40%, 15%, 66%, ?64%, and 36%, respectively.     

Biocenotic dynamics of liquid sewage in the process of its biological purification at aeration stations

A study was made of biological purification of sewage at the aeration stations on the quantitative composition of the main indicator microbes--of bacteria of the coliform group and of the fecal coliform bacilli, enterococci, Proteus, and also pathogenic enterobacteria. There was found a difference in the behaviour of different species of Proteus, i.e. reduction in the process of purification in the numbers of Pr. mirabilis, and a sharp elevation of Pr. morganii content. There was noted an insignificant amount of Pr. vulgaris both before and after the biological purification. It was found that dynamics of biocenosis was influenced by air temperature at the time of collection of the samples. A possibility of reproduction of coliform bacilli serving as one of the factors of autopurification of sewage during the biological purification was confirmed.     

Evaluation of commercial presence-absence test kits for detection of total coliforms, Escherichia coli, and other indicator bacteria

Evaluations of several commercial presence-absence (P-A) test kits were performed over a 6-month period in 1990 by using the Ontario Ministry of the Environment (MOE) P-A test for comparison. The general principles of the multiple-tube fermentation technique formed the basis for conducting the product evaluations. Each week, a surface water sample was diluted and inoculated into 25 99-ml dilution blanks for each of three dilutions. The inoculated dilution blanks from each dilution series were randomly sorted into sets of five. Three of these sets were inoculated into the P-A test kits or vice versa, as required. The other two sets were passed through membrane filters, and one set of five membrane filters was placed onto m-Endo agar LES to give replicate total coliform counts and the other set was placed onto m-TEC agar to give replicate fecal coliform results. A statistical analysis of the results was performed by a modified logistic transform method, which provided an improved way to compare binary data obtained from the different test kits. The comparative test results showed that three of the four commercial products tested gave very good levels of recovery and that the fourth commercial product gave only fair levels of recovery when the data were compared with the data from MOE P-A tests and membrane filter tests. P-A bottles showing positive results after 18 h of incubation that were subcultured immediately in ECMUG tubes frequently could be confirmed as containing total coliforms, fecal coliforms, or Escherichia coli after 6 h of incubation; thus, the total incubation time was only 24 h.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluating a Probabilistic Approach for Simulating Pathogen Removal at a Riverbank Filtration Site in India

In this paper, concentrations of pathogens in the influent and bank filtrate water at a riverbank filtration (RBF) site in Haridwar, India, are simulated by using a probabilistic approach. During the study of the RBF water quality in Haridwar in 2005–2006, it was observed that the river water does not meet World Health Organization and other Bureau of Indian Standards requirements for drinking water quality, especially with respect to bacteriological water quality, i.e., total coliform and fecal coliform levels, and therefore, changes to the river water quality as it moves to an infiltration well are of much relevance. By using the river water quality and the quality of abstracted water from nearby pumping wells, a probabilistic approach is used to study the variation of probability of clogging under different bacteriological qualities of source water. It is observed that the probability of clogging the pores varies with the natural logarithm of the concentrations of pathogens in source water, and the probabilistic approach has the potential to be used to simulate variations in pathogens in riverbank filtrate.     

Application of polymerase chain reaction for the correlation of Salmonella serovars recovered from greyhound feces with their diet

The polymerase chain reaction was employed to correlate Salmonella serovars isolated from fecal material of greyhounds suffering from gastroenteritis with those isolated from the diet fed to the greyhounds prior to onset of diarrhea. Kennels around the Abilene, Kansas, area were contacted and supplied with materials needed to collect a portion of the diet each day. With the onset of diarrhea, the kennels were instructed to ship the fecal material and diet from the previous 10 days to the laboratory for testing. Forty-one fecal samples and corresponding diets were screened for Salmonella, Clostridium perfringens, Campylobacter jejuni, Staphylococcus aureus, Staphylococcus intermedius, and pathogenic (piliated) Escherichia coli by direct culture using standard procedures. The fecal material was also screened for coronavirus and parvovirus using electron microscopy. Thirty-five "normal" fecal samples were screened for all of the above mentioned microorganisms as a control. In addition, the fecal material was screened for E. coli verotoxins I and II and clostridial enterotoxins. A total of 61 Salmonella isolates were recovered from the 41 samples of feces and diet submitted for testing; 31 were recovered from the feces and 30 from the diet. Four Salmonella isolates were recovered from the normal fecal samples. Results obtained by PCR, plasmid profiles, antigenic analysis, and antibiogram profiles indicated that 16 of the 31 isolates recovered from the fecal material were the same strain as that recovered from the diet.     

Fecal Coliform Removal within a Marshland Upwelling System Consisting of Scatlake Soils

The marshland upwelling system (MUS) was installed on private camps in the Grand Bay National Estuarine Research Reserve, Moss Point, Mississippi. The system was evaluated for its effectiveness in removing fecal coliforms from settled, raw wastewater. A suite of studies was performed at flow rates of 1.9, 2.8, and 5.5 L/min and an injection frequency of 30 min every 3 h to investigate fecal coliform removal. An additional study was performed at a flow rate of 2.8 L/min and an injection frequency of 15 min every hour. Overall, the MUS consistently maintained fecal concentrations below effluent regulatory standards for shellfish harvesting waters (14 most probable number of colonies per 100 mL). Mean influent concentrations of 55,269±2,218,016 colony forming units (CFU)/100 mL were reduced to effluent counts of 2.7±14.07 CFU/100 mL (observed in the 1.5 m wells). Three- to four-log reductions in influent counts were observed over the initial 1.4 vector?m from the injection well. The overall removal followed a first-order decay relationship with respect to vector distance, resulting in removal rate constants ranging from 5.6 to 6.6/m and predicted surface concentrations approaching 0 CFU/100 mL. The 2.8 L/min for 30 min every 3 h treatment provided the best effluent quality.     

Evaluating Temporal Variability in Bacterial Indicator Samples for an Urban Watershed

Temporal variability in water quality sampling can lead to under or overestimation of pollution. More frequent sampling during times of expected high variability can reduce temporal bias. However, bacterial indicator measurements require manual sampling and time-intensive and expensive laboratory analysis. Thus, methods to assess the effect of temporal variability would be useful. In this work, fecal coliform and E. coli samples were taken weekly during the recreational season at 25 sites in an urban watershed. The data were categorized into wet versus dry days, and upper versus lower watershed, and the geometric means and geometric standard deviations of various five-sample data sets were analyzed to determine if sample data selection would result in different stream classifications. Results indicate if the bacterial indicator samples are near the regulated limits for water contact recreational use, temporal bias could sway impairment classification decisions. To reduce the temporal bias, sampling data submitted for stream classification should include several sampling groups within the recreational season, particularly for sites near point sources of pollution or with low fecal indicator contamination.     

Feasibility of a Dune Infiltration System to Protect North Carolina Beaches from Fecal Bacteria Contaminated Storm Water

Storm water ocean outfalls discharging into recreational waters pose a human health threat because of increased potential exposure to bacteria and other pathogens. The dune infiltration system (DIS) was designed and implemented at two ocean outfall sites in response to concerns by the North Carolina Department of Transportation and the town of Kure Beach, North Carolina The systems were designed to divert storm water runoff from 1.9?ha (4.7 acre) and 3.2?ha (8.0 acre) watersheds into the beach dunes. Following construction, data were collected from 25 storms during March through October 2006. The systems captured a combined total of nearly 1,800??m3 (63,500??ft3), or 95% of the influent storm water runoff—a significant reduction of runoff volume and peak flow discharging directly onto the beach (p<0.0001). Fecal coliform and enterococci concentrations were measured in the inflowing storm water runoff and groundwater downslope of the systems. Both groundwater bacteria concentrations near the systems were significantly lower than the bacteria concentrations in the inflowing storm water (p<0.001). Furthermore, groundwater fecal coliform concentrations after implementing the DISs were statistically similar to preconstruction levels (p<0.05). The initial results are promising, and the system should be considered for more widespread use. However, further comprehensive research is recommended to more thoroughly understand the viability of the DIS as a storm water best management practice and the fate and transport of the bacteria within the dunes.     

Impact of Microbial Partitioning on Wet Retention Pond Effectiveness

Wet detention basins are among the most common best management practices (BMPs) being implemented as means of complying with United States Phase II storm-water rules and impending Total Maximum Daily Load limits. The effectiveness of these basins for removal of microbial contaminants, one of the most frequent causes of water quality impairment, may be significantly affected by the degree to which microbes associate with particles in storm water. Little is known with regard to where microbial-particle associations are initiated within the storm-water transport chain as flow travels from upland sources (e.g., lawns, parking lots) through storm sewer systems and BMPs and finally on to receiving waters. A similar lack of information exists on the relative concentrations of microbes at each point in the transport chain. Both of these factors have important implications for the location of wet detention basins within a watershed, as well as their anticipated effectiveness. This study tracked the concentrations and partitioning behavior of three indicator organisms (fecal coliform, E. coli, and enterococci) at several locations in the transport chain and also explored the impacts of partitioning on wet pond removal efficiency. Results suggest that microbial-particle association is primarily initiated at upland sources and the degree of microbial partitioning does not vary greatly throughout the transport chain; therefore, treatment ponds will likely be most effective if located near upland contaminant sources. The overall reduction in microbial concentration brought about by the ponds was less than that assumed by most regulatory agencies, but the ponds did show some evidence of preferentially removing particle-associated fecal coliform and E. coli, suggesting that sedimentation is a key removal process. These findings should provide insights useful in the design and implementation of storm-water management strategies.