Municipal Water Treatment Plant Research Articles

COST OF MUNICIPAL WATER TREATMENT PLANT IN THE BIGGER POLISH TOWN IN PODLASKIE PROVINCE FOR THE YEARS 2010–2012

In this paper the operation costs of the municipal water treatment plant in the biggest Polish town in Podlaskie province was analyzed. Capacity of this WTF is 600 m3/h. Water treatment processes are primarily focused on removal of iron, mangnese and turbidity and disinfection by UV rays. Water is taken by 19 wells and then it is oxygenated. From aerators water is addressed to ten filters, which filter water at a speed of 8.5 m/h. The analysis of the operation costs of the municipal water treatment plant was carried out by a method of testing and interpretation of the materials provided by the Water and Sewerage Company in a big town in the Podlaskie Province. It was established that, groundwater treatment plant operation costs, carried out in 2010–2012, showed the highest share of depreciation and remuneration costs.

Long term changes in nutrients, chloride, and phytoplankton density in the nearshore waters of Lake Erie

Monitoring at five municipal water treatment plant intakes revealed several significant trends in Lake Erie's nearshore water quality since the 1960s and 1970s. Phytoplankton densities, in particular the abundance of diatoms, decreased following early phosphorus loading controls and the establishment of dreissenid mussels, while silica concentrations increased. There were notable reductions and breakpoints in the trends in phytoplankton cell densities in consecutive years from the west to the east of the lake (western basin in 1987, central in 1988, and eastern in 1989) coinciding with the reported timing of dreissenid mussel invasion and establishment. There have also been shifts in phytoplankton species composition that were related to variations in total phosphorus, chloride, silica, and nitrate concentrations. Annual mean phosphorus concentrations have decreased significantly and remained low since the early 1990s in the eastern basin, showed no consistent trend in the central basin, and decreased in the western basin. Concentrations have increased in the western basin since the mid-1990s, although not to the levels seen during the early 1980s. Recently, chlorophyll a concentrations have also increased in the western and eastern basins of the lake.

Removal of geosmin and 2-methylisoboneol (2-MIB) by membrane system combined with powdered activated carbon (PAC) for drinking water treatment

Adsorption kinetic tests and step-feeding tests were performed to evaluate adsorption characteristics of geosmin and 2-methylisoborneol (2-MIB). Removal efficiencies of each unit process in powdered activated carbon (PAC) membrane hybrid system were evaluated as well. The hybrid system consists of two unit processes; a coarse powder activated carbon (C-PAC) contactor and a submerged membrane tank. A pilot plant having a capacity of 500m3day−1 was installed in W municipal drinking water treatment plant. C-PAC contactor has C-PAC (80–150 mesh) slurry blanket with a high concentration of 30,000mgL−1 and the blanket is maintained in the contactor without loss. After the adsorption capacity of the C-PAC was exhausted, C-PAC turned into a biological activated carbon. In step feeding tests, 2-MIB and geosmin were continuously injected to the raw water as a concentration of 50ngL−1 for 2-MIB and 200ngL−1 for geosmin. Addition of fresh PAC of 15mgL−1 and 5mgL−1 was required to reduce the concentration of 2-MIB or geosmin below odor threshold concentration, respectively. These values are less than half of required dose from kinetic tests. The removal of Geosmin and 2-MIB by the bio-film formed on the C-PAC in the contactor was accounted for approximately up to 25% of the overall removal. As the raw water temperature increased from 5 to 20°C, the biological removal efficiency was almost doubled. The operating pressure of membrane had been stable when the flux was maintained below 33Lm−2h−1 with recovery rate of 98% for three months. The recovery cleaning is expected every 6 months for the long term operation.

Large Outbreak ofCryptosporidium hominisInfection Transmitted through the Public Water Supply, Sweden

In November 2010, ≈27,000 (≈45%) inhabitants of Östersund, Sweden, were affected by a waterborne outbreak of cryptosporidiosis. The outbreak was characterized by a rapid onset and high attack rate, especially among young and middle-aged persons. Young age, number of infected family members, amount of water consumed daily, and gluten intolerance were identified as risk factors for acquiring cryptosporidiosis. Also, chronic intestinal disease and young age were significantly associated with prolonged diarrhea. Identification of Cryptosporidium hominis subtype IbA10G2 in human and environmental samples and consistently low numbers of oocysts in drinking water confirmed insufficient reduction of parasites by the municipal water treatment plant. The current outbreak shows that use of inadequate microbial barriers at water treatment plants can have serious consequences for public health. This risk can be minimized by optimizing control of raw water quality and employing multiple barriers that remove or inactivate all groups of pathogens.

New water treatment plant features first dissolved‐air flotation system in Illinois

Replacing a nearly 90‐year‐old municipal water treatment plant in Illinois required years of planning and testing ‐ and ended up being the state's first dissolved‐air flotation system.

Alternative method for producing organic fertiliser from anaerobic digestion liquor and limestone powder: High Shear wet granulation

Abstract Generally, the solid and liquid fractions (digestate) from Anaerobic Digestion (AD) energy production are considered as waste. This has a negative impact on the sustainability of AD processes because of the financial outlay required to treat digestate before being discharged into municipal water treatment plants or natural water bodies. The main aim of this research was to investigate feasibility of producing an organic fertiliser using anaerobic digestate and limestone powders as the raw materials employing a high shear granulation process. Two‐level factorial experimental design was used to determine the influence of granulation process variables on, the strength, resistance to attrition and yield of the granules. It was concluded from the study that it is technically feasible to produce organic fertiliser granules of acceptable strength and product yield. Increasing the liquid-to-solid ratio during granulation leads to increased granule strength and better product yield. Although the strength of the granules produced was lower than typical strength of commercial synthetic fertiliser granules (about 5 to 7 MPa), this could be improved by mixing the digestate with a polymeric binder or coating the particles post granulation.

Fusing probability density function into Dempster–Shafer theory of evidence for the evaluation of water treatment plant

The evaluation of the status of a municipal drinking water treatment plant (WTP) is important. The evaluation depends on several factors, including, human health risks from disinfection by-products (R), disinfection performance (D), and cost (C) of water production and distribution. The Dempster-Shafer theory (DST) of evidence can combine the individual status with respect to R, D, and C to generate a new indicator, from which the overall status of a WTP can be evaluated. In the DST, the ranges of different factors affecting the overall status are divided into several segments. The basic probability assignments (BPA) for each segment of these factors are provided by multiple experts, which are then combined to obtain the overall status. In assigning the BPA, the experts use their individual judgments, which can impart subjective biases in the overall evaluation. In this research, an approach has been introduced to avoid the assignment of subjective BPA. The factors contributing to the overall status were characterized using the probability density functions (PDF). The cumulative probabilities for different segments of these factors were determined from the cumulative density function, which were then assigned as the BPA for these factors. A case study is presented to demonstrate the application of PDF in DST to evaluate a WTP, leading to the selection of the required level of upgradation for the WTP.

Evaluation of the logistic model for GAC performance in water treatment

Full‐scale field measurement and rapid small‐scale column test data from the Greater Cincinnati (Ohio) Water Works (GCWW) were used to calibrate and investigate the application of the logistic model for simulating breakthrough of total organic carbon (TOC) in granular activated carbon (GAC) contactors. The logistic model parameters were estimated using a nonlinear regression algorithm. The calibrated logistic model was validated using data from multiple GAC contactors operating in parallel at the GCWW Richard Miller Treatment Plant. This facility has experienced large seasonal variations in flow rate and TOC influent concentration. Proper estimation of logistic model parameters depends on the run‐time length of the GAC breakthrough data set. A critical minimum runtime threshold must be achieved to produce reliable parameter estimates. A properly calibrated logistic model provides an effective tool for accurately simulating the blended TOC concentrations in the GAC contactor effluent at a municipal drinking water treatment plant.

Diversity and antibiotic resistance of Acinetobacter spp. in water from the source to the tap

Acinetobacter spp. are ubiquitous bacteria in the environment. Acinetobacter spp. isolated from a municipal drinking water treatment plant and from connected tap water were identified to the species level on the basis of rpoB gene partial sequence analysis. Intraspecies variation was assessed based on the analysis of partial sequences of housekeeping genes (rpoB, gyrB, and recA). Antibiotic resistance was characterized using the disk diffusion method and isolates were classified as wild or non-wild type (non-WT), according to the observed phenotype. The strains of Acinetobacter spp. were related to 11 different validly published species, although three groups of isolates, presenting low rpoB sequence similarities with previously described species, may represent new species. Most of the isolates were related to the species A. johnsonii and A. lwoffii. These two groups, as well as others related to the species A. parvus and A. tjernbergiae, were detected in the water treatment plant and in tap water. Other strains, related to the species A. pittii and A. beijerinckii, were isolated only from tap water. Most of the isolates (80%) demonstrated wild type (WT) to all of the 12 antibiotics tested. Non-WT for tetracycline, meropenem, and ceftazidime, among others, were observed in water treatment plant or in tap water samples. Although, in general, this study suggests a low prevalence of acquired antibiotic resistance in water Acinetobacter spp., the potential of some species to acquire and disseminate resistance via drinking water is suggested.

Identifying host sources, human health risk and indicators of Cryptosporidium and Giardia in a Canadian watershed influenced by urban and rural activities

Cryptosporidium and Giardia were characterized in a watershed in southern Ontario, Canada, over a 2½ year period. River samples were collected every two weeks, primarily near a municipal drinking water treatment plant intake. Cryptosporidium and Giardia were frequently detected with an overall occurrence rate of 88 and 97%, respectively. Giardia concentrations were higher than Cryptosporidium, with median values of 80 cysts 100 L(-1) and 12 oocysts 100 L(-1), respectively. Although pathogens rarely show a significant relationship with fecal or water quality indicators, this study determined that Cryptosporidium, but not Giardia, was significantly correlated with Escherichia coli, turbidity and river flow. There was no correlation between the two types of protozoa, and only Giardia showed a seasonal trend with higher concentrations at cold water temperatures. Cryptosporidium genotyping of all samples found that farm animals and wildlife were an important contributor of oocysts in the watershed, and that Cryptosporidium strains/genotypes of medium to high risk for human infection (C. hominis, C. parvum and C. ubiquitum) were detected in 16% of samples. This study was able to identify Cryptosporidium host sources and human health risk, and to identify differences between Cryptosporidium and Giardia occurrence in the watershed.

Artificial neural network modeling for predict performance of pressure filters in a water treatment plant

Abstract Pressure filters are popular in small municipal water treatment plants. One of the principles for designing and using the various units of water treatment plants is the ability of assigning and predicting the performance of those units under different and various conditions that could be verified by making pilot scale tests and could be modeled by means of available programs and software such as artificial neural network. The goals of this study that was conducted to predict pressure filter efficiency are: (1) evaluations of pressure filter efficiency for turbidity removal under different conditions such as turbidity of raw water, filtration rate and filter pressure changes; (2) statistical analysis of results and determination of the minimum and maximum and maximum effluent turbidity from filter; (3) application of Artificial Neural Network as a suitable model of filter efficiency for turbidity removal; and (4) determination of considered model index for the prediction of similar filters efficiencies. For approaching those goals, pilot designation, sampling and analysis were done for 1,300 samples, and the maximum and the minimum effluent turbidity from filter were determined based on statistical analyses. Different structure of Artificial Neural Network were evaluated based on results, and the best structure was selected and its indexes was proposed for future studies; for example the best value for different network schemes like momentum coefficient and training rate were 0.5 and 0.2, respectively.

Trends in nutrients, phytoplankton, and chloride in nearshore waters of Lake Ontario: Synchrony and relationships with physical conditions

Consistent routine monitoring at four municipal water treatment plant intakes revealed dramatic long-term changes in water quality in the nearshore waters of Lake Ontario over the last three decades. Total P concentrations decreased significantly, but concentrations leveled off at around 0.01mg/L after 1996. Silica (Si) and nitrate+nitrite-N (NO2+3) concentrations increased and chloride concentrations decreased until the mid-1990s after which they began to increase. There were significant decreasing trends in chlorophyll a and algal cell densities, the greatest rate of decrease being observed in diatom abundance. Interannual and seasonal variations in all parameters were synchronous between stations, indicating the influence of drivers such as climate and hydrology operating at a broad scale. The interannual variations in NO2+3 and Si concentrations were significantly related to snow depth, and in Si were also related to annual climate indices, the North Atlantic Oscillation Index (NAOI) and Southern Oscillation Index (SOI), the two most dominant large-scale atmospheric circulation models controlling climate in large parts of the northern hemisphere. The relationships indicated that Si concentrations were lower in the milder, drier years and higher when winters were colder and precipitation and snow depth were greater.

Investigation on the removal of natural and synthetic estrogens using biofilms in continuous flow biofilm reactors and batch experiments analysed by gas chromatography/mass spectrometry

The degradation of the natural estrogen 17β-estradiol and the synthetic steroid hormone 17α-ethinylestradiol, two estrogens already detected in surface waters at low concentration levels, was investigated using continuous flow biofilm reactors and batch experiments. Biofilms in continuous flow experiments were created by natural organisms from river systems of the national park Unteres Odertal, Germany, whereas batch experiments were performed with isolated bacterial strains derived from biofilms. The analytical method, including solid phase extraction, silylation of analytes and measurement with GC/MS, was optimised for the target compounds 17β-estradiol, 17α-ethinylestradiol and the possible metabolites estrone and estriol. The performance characteristics of the analytical method, namely recovery, standard deviations, method detection limits (MDL) and method quantification limits (MQL), were evaluated for accurate interpretation of degradation experiments. Continuous flow biofilm reactors were operated with two different nutrient media under dosage of estradiol and ethinylestradiol. Both estrogens were rapidly degraded within several hours; the metabolite estrone (from estradiol as well as from ethinylestradiol) was detected in significant amounts and was further decomposed. In additional batch experiments using isolated bacterial strains from the natural biofilms to decompose estradiol and ethinylestradiol, different metabolisms of isolates were explored. Five of the 15 isolated bacterial strains tested degraded estradiol and ethinylestradiol with different degradation rates. The results suggest that biofilms from national park Unteres Odertal possess a high capability to aerobically decompose natural and also synthetic estrogens so that these microorganisms could provide enhanced removal of pollutants in municipal water treatment plants.

QUALIDADE MICROBIOLÓGICA DE AFLUENTES E EFLUENTES DE ESTAÇÕES DE TRATAMENTO DE ÁGUA E ESGOTO DE GOIÂNIA , GOIÁS

This study was conducted to evaluate microbiological quality of two importantsurface water from Meia Ponte river and João Leite stream, which are used fordrinking purposes in Goiania city, Goias State. In addition, treated water, wastewaterand treated effluent from municipal Water and Sewage Treatment Plants wereanalyzed. The study also aimed to correlate pluviometric density and the physical,chemical, and microbiological parameters in water, by Pearson Correlation statisticaltest. The coliforms concentration, Salmonella presence, and the physical andchemical parameters were evaluated in raw and treated water, wastewater, and treated effluent samples collected in municipal Water and Sewage Treatment Facilities in 2005. According to the results obtained, Meia Ponte river was classified as Class Iand João Leite stream as Class III, during the analyzed period. Pluviometric densitywas correlated to fecal contamination and some physical and chemical parametersof water (color and turbidity) in Meia Ponte river and João Leite stream. Watertreatment was considered satisfactory; however, the primary treatment in the SewageTreatment Facility was not able to decrease significantly the fecal load of wastewater,being an important source of contamination to the Meia Ponte river.

Photodegradation and toxicity changes of antibiotics in UV and UV/H 2O 2 process

The photodegradation of three antibiotics, oxytetracycline (OTC), doxycycline (DTC), and ciprofloxacin (CIP) in UV and UV/H 2O 2 process was investigated with a low-pressure UV lamp system. Experiments were performed in buffered ultrapure water (UW), local surface water (SW), and treated water from local municipal drinking water treatment plant (DW) and wastewater treatment plant (WW). The efficiency of UV/H 2O 2 process was affected by water quality. For all of the three selected antibiotics, the fastest degradation was observed in DW, and the slowest degradation occurred in WW. This phenomenon can be explained by R OH,UV, defined as the experimentally determined OH radical exposure per UV fluence. The R OH,UV values represent the background OH radical scavenging in water matrix, obtained by the degradation of para-chlorobenzoic acid (pCBA), a probe compound. In natural water, the indirect degradation of CIP did not significantly increase with the addition of H 2O 2 due to its effective degradation by UV direct photolysis. Moreover, the formation of several photoproducts and oxidation products of antibiotics in UV/H 2O 2 process was identified using GC–MS. Toxicity assessed by Vibrio fischer (V. fischer), was increased in UV photolysis, for the photoproducts still preserving the characteristic structure of the parent compounds. While in UV/H 2O 2 process, toxicity increased first, and then decreased; nontoxic products were formed by the oxidation of OH radical. In this process, detoxification was much easier than mineralization for the tested antibiotics, and the optimal time for the degradation of pollutants in UV/H 2O 2 process would be determined by parent compound degradation and toxicity changes.

Trace Elements in the Oldman River of Southern Alberta

Abstract The Oldman River in southern Alberta is a mainstem river used extensively by aquatic life, for community drinking water, irrigation water, recreation, and livestock watering. Therefore, maintaining the water quality of this important river is critical for watershed health. We collected water samples weekly from three locations on the middle reach of the Oldman River from 2004 to 2006. The locations were: Lethbridge Municipal Water Treatment plant (MWTP) (Site 1), Fort MacLeod MWTP (Site 2), and a river bank sampling location downstream of the latter site (Site 3). Water samples were analyzed for background physical and chemical variables, and for selected trace elements (Al, Fe, Cd, Co, Cr, Cu, Mn, Mo, Ni, Pb, Zn). The aquatic life, community, irrigation, and livestock water quality guidelines at the three sites were most frequently exceeded by Cu (27-48%), Al (3.3-57%), Co (18-26%), and Al (2.3%), respectively. Concentrations of certain trace elements were highest in the spring or during years of above average precipitation, and were likely associated with increased loads of suspended sediments during high flow conditions. Turbidity, water temperature, electrical conductivity, river level, and precipitation generally had a positive effect, and pH had a negative effect on certain trace element concentrations.

Determination of molybdenum in extracts of soil and sewage sludge CRMs after fractionation by means of BCR modified sequential extraction procedure

A modified three-step sequential extraction procedure proposed by the Commission of European Communities Bureau of Reference (BCR) was applied to certified reference materials of three different soil groups (rendzina, luvisol, and cambisol) and sewage sludge of different compositions originating from a municipal water treatment plant in order to assess potential mobility and the distribution of molybdenum in the resulting fractions. In the soils examined, molybdenum was present almost entirely in the mineral lattice, the content of molybdenum in the fractions of the studied reference materials of sludges was predominant in the fraction, represents Mo bound to organic matter and sulphide. The internal check of accuracy was performed on the results of the sequential extraction by comparing of the extractable amounts of molybdenum in the sequential procedure with the results of the pseudototal digestion of original samples. The recovery ranged from 96 to 101% and the precision (RSD) in the extracts was below 10%.

Oxidation kinetics of cyclophosphamide and methotrexate by ozone in drinking water

This study investigates the aqueous degradation by ozone of two target cytostatic drugs, cyclophosphamide and methotrexate. A column switching technique for on-line solid phase extraction (SPE) coupled to electro-spray ionization-tandem mass spectrometry (LC–ESI-MS/MS) was used for the simultaneous detection of the trace contaminants. The second-order kinetic rate constants for the reaction of cyclophosphamide with molecular ozone and hydroxyl radicals were determined in bench-scale experiments at pH 8.10. The molecular ozone oxidation kinetics was studied in buffered ultrapure water and compared to the oxidation kinetics in natural water from a municipal drinking water treatment plant in the province of Quebec (Canada). For cyclophosphamide, the degradation rate constant with molecular ozone in ultrapure water was low ( k O 3 = 3.3 ± 0.2 M −1 s −1) and the extent of oxidation was linearly correlated to the ozone exposure. The impact of water quality matrix on oxidation efficacy was not significant during direct ozone reaction ( k O 3 = 2.9 ± 0.3 M −1 s −1). The rate constant with hydroxyl radicals was higher at 2.0 × 10 9 M −1 s −1. Methotrexate reacted quickly with molecular ozone at dosages typically applied in drinking water treatment ( k O 3 > 3.6 × 10 3 M −1 s −1). Overall, the results confirmed that organic compounds reactivity with ozone was dependent of their chemical structure. Ozone was very effective against methotrexate but high oxidant concentration × contact time (CT) values were required to completely remove cyclophosphamide from drinking water. Further studies should be conducted in order to identify the ozonation by-products and explore the impact of ozone on their degradation and toxicity.

Occurrence of motile Aeromonas in municipal drinking water and distribution of genes encoding virulence factors

Aeromonas-associated cases of gastroenteritis are generally considered waterborne. The purpose of this study was to evaluate the potential microbiological risk associated with the presence of these bacteria in public drinking water. Over a period of one year, 132 drinking-water samples were monitored in León (NW of Spain, 137,000 inhabitants) for mandatory drinking-water standards and the occurrence of Aeromonas spp. Samples were taken at the municipal water treatment plant, one storage facility, and two public artesian drinking-water fountains. Because of low numbers of coliforms or Clostridium perfringens, the non-compliance rate with microbial standards was 3.8% whereas the percentage of positive samples for motile mesophilic Aeromonas was 26.5%. For all but two samples, Aeromonas was recovered between October and early March when the temperature was below 14 °C and the residual chlorine ranged from 0.21 to 0.72 mg/l. An apparent relationship was observed between rainfall and the incidence of Aeromonas. The 35 selected Aeromonas isolates were identified as A. caviae and A. media. The alt and laf genes were present in all isolates, the aerA gene was present in six isolates, and the four remaining genes investigated ( hlyA, ast, stx1 and stx2) were absent. The combinations of putative virulence genes were: aerA − /hlyA −/ alt +/ ast −/ laf +/ stx1 −/ stx2 − (82.9%) and aerA + /hlyA −/ alt +/ ast −/ laf +/ stx1 −/ stx2 − (17.1%). None of the isolates bore plasmids. As Aeromonas strains harbouring two or more virulence-associated genes have the potential to cause disease by direct transmission via drinking water or by water use in food preparation, it would be advisable to control excessive numbers of these bacteria in drinking-water supplies.

Predicting Atrazine Levels in Water Utility Intake Water for MCL Compliance

To protect human health, atrazine concentrations in finished municipal drinking water must not exceed a maximum contaminant level (MCL) of 3 microg/L, as determined by a specific monitoring regime mandated by the United States Environmental Protection Agency. Atrazine levels were monitored along tile-fed drainage ditches draining to a major drinking water source and used to predict MCL exceedance frequencies of intake and finished drinking water. Water samples were collected daily at eight monitoring sites located at the outlets of subbasins draining 298-19 341 ha (736-47 794 ac). Flow-weighted average (FWA) atrazine concentrations ranged from 0.9 to 9.8 microg/L, and were above 3 microg/L for the majority of sites, including the largest site, which represents water quality at the intake of the local municipal water treatment plant. However, a relatively low percentage of samples near the water utility intake exceeding 3 microg/L atrazine (10.4%) made this problem difficult to detect. In order to have a 95% probability of detecting any intake sample exceeding 3 microg/L atrazine in a drainage system exceeding 3 microg/L atrazine on a FWA basis, sampling frequency would need to be every 7 days or more often during the second quarter when the potentials for field atrazine losses and temporal variability of atrazine concentrations are highest.