scholarly journals Cause of rapid monochloramine decay observed in treated water

2016 ◽  
Vol 17 (3) ◽  
pp. 752-758 ◽  
Author(s):  
Sam Hancock ◽  
Martin Harris ◽  
David Cook
Keyword(s):  
Water Treatment ◽  
Water Samples ◽  
Pilot Scale ◽  
The Other ◽  
Biological Degradation ◽  
Filter Media ◽  
Rapid Decay ◽  
Treated Water ◽  
Water Treatment Plants ◽  
The Impact

Rapid monochloramine decay has been observed in the product water of three River Murray water treatment plants (WTPs). Previous investigations identified that rapid monochloramine decay was microbiological in nature and observed in samples taken after media filtration but was absent in filtered water samples from a fourth WTP of similar design. The filters at the WTP not exhibiting rapid decay are backwashed with filtered non-disinfected water whereas the other WTPs backwash with treated chloraminated water. It was therefore hypothesised that backwashing filters with chloraminated water was the cause of the rapid monochloramine decay. A pilot-scale study was conducted to investigate the impact of backwashing with chloraminated water on the occurrence of microbiologically accelerated monochloramine decay. Additional samples were analysed to assess the impact of chloraminated backwash water on N-Nitrosodimethylamine (NDMA) formation and biological degradation of taste and odour compounds 2-methyl isoborneol (MIB) and geosmin in the filter media. Backwashing with chloraminated filtered water was concluded to be the cause of the observed rapid monochloramine decay, with rapid decay observed within 8 weeks for the filters backwashing with chloramines. Additionally, backwashing with chloraminated filtered water was observed to increase NDMA formation and impair the biological degradation performance of MIB and geosmin.

scholarly journals Organophosphate Flame Retardants and Perfluoroalkyl Substances in Drinking Water Treatment Plants from Korea: Occurrence and Human Exposure

2021 ◽  
Vol 18 (5) ◽  
pp. 2645
Author(s):  
Wonjin Sim ◽  
Sol Choi ◽  
Gyojin Choo ◽  
Mihee Yang ◽  
Ju-Hyun Park ◽  
...  
Keyword(s):  
Drinking Water ◽  
Water Treatment ◽  
Water Samples ◽  
Flame Retardants ◽  
Hazard Index ◽  
Drinking Water Treatment ◽  
Perfluoroalkyl Substances ◽  
Raw Water ◽  
Treated Water ◽  
Water Treatment Plants

In this study, the concentrations of organophosphate flame retardants (OPFR) and perfluoroalkyl substances (PFAS) were investigated in raw water and treated water samples obtained from 18 drinking water treatment plants (DWTPs). The ∑13OPFR concentrations in the treated water samples (29.5–122 ng/L; median 47.5 ng/L) were lower than those in the raw water (37.7–231 ng/L; median 98.1 ng/L), which indicated the positive removal rates (0–80%) of ∑13OPFR in the DWTPs. The removal efficiencies of ∑27PFAS in the DWTPs ranged from −200% to 50%, with the ∑27PFAS concentrations in the raw water (4.15–154 ng/L; median 32.0 ng/L) being similar to or lower than those in the treated water (4.74–116 ng/L; median 42.2 ng/L). Among OPFR, tris(chloroisopropyl) phosphate (TCIPP) and tris(2-chloroethyl) phosphate (TCEP) were dominant in both raw water and treated water samples obtained from the DWTPs. The dominant PFAS (perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA)) in the raw water samples were slightly different from those in the treated water samples (PFOA, L-perfluorohexane sulfonate (L-PFHxS), and PFHxA). The 95-percentile daily intakes of ∑13OPFR and ∑27PFAS via drinking water consumption were estimated to be up to 4.9 ng/kg/d and 0.22 ng/kg/d, respectively. The hazard index values of OPFR and PFAS were lower than 1, suggesting the risks less than known hazardous levels.

scholarly journals Effectiveness of vertical subsurface wetlands for iron and manganese removal from wastewater in drinking water treatment plants

2019 ◽  
Vol 24 (1) ◽  
pp. 135-163
Author(s):  
Jader Martínez Girón ◽  
Jenny Vanessa Marín-Rivera ◽  
Mauricio Quintero-Angel
Keyword(s):  
Drinking Water ◽  
Wastewater Treatment ◽  
Water Treatment ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Water Treatment Plant ◽  
Pilot Scale ◽  
Treatment System ◽  
Water Treatment Plants ◽  
Significant Difference

Population growth and urbanization pose a greater pressure for the treatment of drinking water. Additionally, different treatment units, such as decanters and filters, accumulate high concentrations of iron (Fe) and manganese (Mn), which in many cases can be discharged into the environment without any treatment when maintenance is performed. Therefore, this paper evaluates the effectiveness of vertical subsurface wetlands for Fe and Mn removal from wastewater in drinking water treatment plants, taking a pilot scale wetland with an ascending gravel bed with two types of plants: C. esculenta and P. australis in El Hormiguero (Cali, Colombia), as an example. The pilot system had three upstream vertical wetlands, two of them planted and the third one without a plant used as a control. The wetlands were arranged in parallel and each formed by three gravel beds of different diameter. The results showed no significant difference for the percentage of removal in the three wetlands for turbidity (98 %), Fe (90 %), dissolved Fe (97 %) and Mn (98 %). The dissolved oxygen presented a significant difference between the planted wetlands and the control. C. esculenta had the highest concentration of Fe in the root with (103.5 ± 20.8) µg/g ; while P. australis had the highest average of Fe concentrations in leaves and stem with (45.7 ± 24) µg/g and (41.4 ± 9.1) µg/g, respectively. It is concluded that subsurface wetlands can be an interesting alternative for wastewater treatment in the maintenance of drinking water treatment plants. However, more research is needed for the use of vegetation or some technologies for the removal or reduction of the pollutant load in wetlands, since each drinking water treatment plant will require a treatment system for wastewater, which in turn requires a wastewater treatment system as well.

Characterization and destabilization of spent filter backwash water particles

2002 ◽  
Vol 2 (2) ◽  
pp. 115-122 ◽  
Author(s):  
A. Adin ◽  
L. Dean ◽  
F. Bonner ◽  
A. Nasser ◽  
Z. Huberman
Keyword(s):  
Water Treatment ◽  
Chemical Characterization ◽  
Physical Parameters ◽  
Ph Measurements ◽  
Particle Count ◽  
Water Treatment Plants ◽  
Physical Chemical ◽  
Organic Particles ◽  
The Impact

Inorganic and organic particles, including bacteria, viruses and parasites, which are retained within a granular filter during surface water filtration, are removed by backwashing the filter with clean water or water and air. The objective of the study was to characterize SFBW and determine its treatability by coagulation. Microbial and physical-chemical characterization of SFBW collected from a number of different water treatment plants was performed. Experiments to determine the impact of coagulation/flocculation on the SFBW samples were also conducted. SFBW was collected from six different water treatment plants and analyzed for microbial and physical parameters. Physical characterization was done on SFBW collected from all of the treatment plants. Turbidity and pH measurements were taken over the course of the backwash run, and the backwash samples were collected in two to four 20 L containers. A number of parameters were measured for the samples in each container, as well as for SFBW composites made by mixing equal portions of the container contents. The measured parameters included: turbidity, pH, TSS, DOC, UV-254 and alkalinity. Jar tests were carried out on individual containers, on SFBW composite and on SFBW composite that was allowed to settle for one hour. Turbidity and particle count data was collected for both settled and filtered samples.

Bacteriophage removal in water treatment plants

1995 ◽  
Vol 31 (5-6) ◽  
pp. 69-73 ◽  
Author(s):  
J. Jofre ◽  
E. Ollé ◽  
F. Lucena ◽  
F. Ribas
Keyword(s):  
Water Treatment ◽  
Distribution Network ◽  
Bacteroides Fragilis ◽  
The Other ◽  
Model Organisms ◽  
Raw Water ◽  
Somatic Coliphages ◽  
Treatment Processes ◽  
Water Treatment Plants ◽  
Human Enteric Viruses

Presence of bacteriophages was evaluated at different stages of two water treatment plants in order to investigate the usefulness of phages as model organisms for assessing the efficiency of the processes. Bacteriophages tested were somatic coliphages, F-specific coliphages and phages infecting Bacteroides fragilis. The presence of human enteric viruses was determined as well in the raw water, the finished water and in samples taken in the distribution network. Results show that in these particular treatment plants, which include prechlorination, phages infecting B. fragilis are more resistant to the treatment processes than the other two phages studied.

scholarly journals Turbidity removal by rapid sand filter using anthracite coal as capping media

2021 ◽  
Vol 4 (1) ◽  
pp. 69-73
Author(s):  
Gopal Tamakhu ◽  
Iswar Man Amatya
Keyword(s):  
Comparative Analysis ◽  
Water Treatment ◽  
Bituminous Coal ◽  
Pilot Scale ◽  
Sand Filters ◽  
Turbidity Removal ◽  
Sand Filter ◽  
Filter Materials ◽  
Water Treatment Plants ◽  
Anthracite Coal

Rapid sand filters are very common in all conventional water treatment plants. Capping of existing rapid sand filters can be the promising method of improving the performance of rapid sand filters. Capping is process in which upper sand bed layer of few cm is replaced with capping material. However, this technique is limited in India due to unavailability of filter materials apart from sand. Some materials suitable for capping are anthracite coal, PVC granules, bituminous coal, broken bricks, etc. The attempt is made to study the effect of capping of Rapid sand filters by the use of anthracite coal as a capping media by pilot scale study. A series of test runs and experiments using different influent turbidity were tried. The pilot scale study has shown very encouraging results. Comparative analysis shows that higher rate of filtration is possible along with higher filter run and less backwash requirement. In the present work, conventional rapid sand filter and capped rapid sand filter are compared.

Halogenated Phenols in Water at Forty Canadian Potable Water Treatment Facilities

1986 ◽  
Vol 69 (5) ◽  
pp. 807-810
Author(s):  
Bishop B Sithole ◽  
David T Williams
Keyword(s):  
Water Treatment ◽  
Water Samples ◽  
Potable Water ◽  
Treatment Plant ◽  
Water Type ◽  
Raw Water ◽  
Mean Values ◽  
Treated Water ◽  
Halogenated Phenols ◽  
Potable Water Treatment

Abstract Samples of raw and treated water were collected once in each of 3 seasons at 40 potable water treatment plants across Canada and were analyzed for phenol and 33 halogenated phenolic compounds including chlorophenols, bromophenols, bromochlorophenols, and chloroguaiacols. Eighteen of the compounds were not found at any treatment plant; phenol and each of the remaining halogenated phenols were found in at least 1 sample. Pentachlorophenol was the only halogenated phenolic compound found in more than 20% of the raw water samples in the fall and winter samples at levels up to 53 ng/L with mean values of 1.9 and 2.8 ng/L, respectively. No halogenated phenols were detected in raw water summer samples. The halogenated phenols found most frequently in treated water samples were 4-chloro-, 2,4-dichloro-, 2,4,6- trichloro-, and bromodichlorophenols. Mean values were less than 15 ng/L and maximum values seldom exceeded 100 ng/L. Most of the positive values for the treated water samples were found at 8 of the 40 treatment plants but no correlations could be found between halogenated phenol levels and raw water type, treatment process, or chemical dosages.

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