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WTP Rozgrund, which was used to treat to the water from Rozgrund reservoir, must have been set out of operation due to the deteriorated quality of the water and its smell. The aAim of this work was to perform the pilot-plant tests, with the goal ofaiming to treating water from the reservoir to achieveand get the compliantying water quality of the water. Conventional water treatment concerning coagulation, flocculation, and filtration with two different filtration fillings – Filtralite Mono-MultiFine and filter sand with black-coal material Carboziar – was compared with conventional treatments with filter sand and Carboziar complemented with filtration through granulated active coal (Norit 830), the ultrafilration using fully automated equipment with membrane module UA-640 (Microdyn-Nadir), and ultrafiltration combined with active granulated carbon. Monitored wereas the pH, turbidity, color, alkalinity, CODMn, TOC, aluminum, number and size of particles, and hydrobiology in the samples of raw and treated water. Obtained results provided that the two most suitable treatment technologies were the filtration with double layer filling consisting of sand and antracite combined with filtration via GAU (removal efficiency of CODMn and turbidity was 90.5% and 85%, respectively) and the ultrafiltration combined with GAU (82.6% for CODMn and 89% for turbidity removal). Biological activation after the treatment was not found. [ABSTRACT FROM AUTHOR]

Copyright of Archives of Environmental Protection is the property of Polish Academy of Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Clogging of rapid sand filters during heavy rainfall causes surface water treatment plants to stop their operations until the river water turbidity decreases to a level that the rapid sand filter is capable of filtering. As clogging of rapid sand filters is impediment in surface water treatment, two-stage crossflow pre-filtration with fabric filter media (linen, crepe-backed satin, burlap, and cotton) was considered in a previous study by Davis and Ekwue (2020) as a possible solution. Pre-filtration with linen fabric filter medium was found to be the most efficient at retaining particles. The present paper incorporated properties of various fabrics previously measured and identified by Davis and Ekwue (2020) with the aim of identifying ideal fabric properties that were effective in removing particles from turbid water. Mechanisms of filtration (surface straining, depth filtration and cake filtration) depicted by each selected fabric during two-stage crossflow pre-filtration were identified and compared to the operation of standard filter media (absorbent, adsorbent, biological and woven). The Davies equation was used to calculate the flow of water through single layer and four layers of fabric filter media. Results indicate that no one specific fabric property could be used to proclaim a fabric as the ideal filter media, but rather all properties of the various fabric contribute to their performance during filtration. Linen fabric was once again determined as the fabric type most efficacious at retaining particles during two-stage crossflow pre-filtration of turbid river water and is therefore recommended [ABSTRACT FROM AUTHOR]

This pilot-scale research was conducted at Ahvaz water treatment plant to investigate the removal of total organic carbon from surface waters by Ag2O/CuFe2O4-loaded silica media filters. Ag2O/CuFe2O4-loaded silica media filters were made with an internal diameter of 5 cm and a height of 150 cm to investigate the efficiency of filter-loaded media on the removal of total organic carbon, and the filter media put to place at 100 cm height inside the filter. The influent TOC of pilot filter was 8 to 10 mg/L. The maximum TOC removal by the silica sand filter was about 38%, while the Ag2O/CuFe2O4-loaded silica sand filter removed more than 97% of the influent TOC in the first 4 h at 120 m3/m2·d filtration rate, pH 7, temperature 25°C and turbidity 10 NTU. Also, the results of TOC removal in different turbidity (10, 25, and 50 NTU) showed that the most TOC removal was in 10 NTU turbidity and then in 25 and 50 NTU, the rate of TOC removal in 8th hour was 97% and 96.7%, respectively. The obtained results of this study confirmed that the studied nanoparticles had positive effects on the reduction/removal of TOC in surface water sources. Also, the results of our study showed that the use of Ag2O/CuFe2O4-loaded silica media filter can remove a significant amount of TOC in various conditions such as turbidity, loading rate, pH and temperature from raw water. [ABSTRACT FROM AUTHOR]

Microplastic (MP) has been a new emerging contaminant in the municipal water supply. A water treatment process is a key to producing high-quality and safe drinking water. The performance of a conventional drinking water treatment plant (CDWTP) to remove MPs is questionable. This research aimed to investigate the performance of 2 CDWTPs in East Java in removing MPs. Full-stage treatment in two CDWTPs consisted of intake, pre-sedimentation, coagulation-flocculation, sedimentation, sand filter, and disinfection units. Five L water samples were collected with a grab sampling technique in the sampling points of intake and outlet of each water treatment unit. MP abundance and characteristics in each sample were determined using a Sunshine SZM-45T-B1 stereomicroscope and a Nicolet i10 FTIR spectrophotometer. Total MP removal efficiencies in CDWTPs I and II were 66 and 62%, respectively. The coagulation-flocculation unit performed the highest MP removal efficiencies (56%). The MP with 1-350 μm size achieved lower removal efficiencies (33-53%) than that with 351-<5,000 μm size (53-76%). The removal efficiencies of fiber, fragment, and film in the CDWTPs were 61-65%; 86-100%; and 100%, respectively. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Engineering (17264073) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sand filters (SFs) are common treatment processes for nitrogen pollutant removal in drinking water treatment plants (DWTPs). However, the mechanisms on the nitrogen-cycling role of SFs are still unclear. In this study, 16S rRNA gene amplicon sequencing was used to characterise the diversity and composition of the bacterial community in SFs from DWTPs. Additionally, metagenomics approach was used to determine the functional microorganisms involved in nitrogen cycle in SFs. Our results showed that Pseudomonadota, Acidobacteria, Nitrospirae and Chloroflexi dominated in SFs. Subsequently, 85 high-quality metagenome-assembled genomes (MAGs) were retrieved from metagenome datasets of selected SFs involving nitrification, assimilatory nitrogen reduction, denitrification and anaerobic ammonia oxidation (anammox) processes. Read mapping to reference genomes of Nitrospira and the phylogenetic tree of the ammonia monooxygenase subunit A gene, amoA, suggested that Nitrospira is abundantly found in SFs. Furthermore, according to their genetic content, a nitrogen metabolic model in SFs was proposed using representative MAGs and pure culture isolate. Quantitative real-time polymerase chain reaction (qPCR) showed that ammonia-oxidising bacteria (AOB) and archaea (AOA), and complete ammonia oxidisers (comammox) were ubiquitous in the SFs, with the abundance of comammox being higher than that of AOA and AOB. Moreover, we identified a bacterial strain with a high NO3-N removal rate as Pseudomonas sp. DW-5, which could be applied in the bioremediation of micro-polluted drinking water sources. Our study provides insights into functional nitrogen-metabolising microbes in SFs of DWTPs. [ABSTRACT FROM AUTHOR]

Egypt suffers from water scarcity. In water treatment plants using sand filters, a significant amount of treated water is consumed, estimated at 10%–15% of the filtered water during backwashing. The objective of this study is to determine the most effective way to reduce the amount of treated water used for backwashing. The methodology of this study was to evaluate the effects of air and water rates, treated water turbidity of 1.6 NTU or slightly higher synthetic turbidity of 4.0 NTU, and media type with single or dual media on reducing treated water consumption during rapid sand filter backwashing procedures. The experimental set up was a bench-scale filter operated at a filtration rate of 189 m3/m2/day. Backwashing with the right water and air rates reduce water usage by 18%, enhanced process performance, and reduced the ripening period. Backwashing using synthetic turbid water recovered 100% of the treated water and improved the ripening duration without affecting backwashing efficiency. This study concluded that backwashing the dual media filter with silica sand and activated carbon achieved the highest treated backwash water consumption by approximately 60%. While anthracite coal was utilized as a dual-media filter, the least reduction in treated water consumption was discovered. [ABSTRACT FROM AUTHOR]

This study describes the ability of a yeast strain, Aureobasidium pullulans KKUY0701 isolated from eutrophic lake to eliminate Cylindrospermopsis raciborskii and cylindrospermopsin (CYN) toxin. The anti-cyanobacterial activity of this yeast strain was evaluated by growing with living cells and filtrate of C. raciborskii. CYN bioremoval was assayed using living and heat-inactivated yeast cells. Both living cells and filtrate of this yeast strain were able to suppress the growth of C. raciborskii, with total cell death occurring at day 2 and day 3, respectively. Living and inactivated yeast cells, but not yeast filtrate, reduced CYN concentrations released into cyanobacterial cultures, indicating that this toxin might be removed from the culture medium via absorption onto yeast surface rather than enzymatic biodegradation. The adsorption experiments also confirmed the elimination of CYN by living and heat-inactivated yeast. Nevertheless, inactivated yeast exhibited higher capacity (K = 3.3) and intensity (n = 1.4) than living yeast (K = 1.9, n = 1) for CYN adsorption. The study suggests that this yeast strain could be employed for bioremediation of Cylindrospermopsis blooms in freshwaters. Additionally, heat-inactivated yeast biomass could be used in slow sand filters for elimination of CYN in drinking water treatment plants. [ABSTRACT FROM AUTHOR]

The aim of the study was to determine the doses of selected bioelements delivered to the body as a result of consuming water from various types of intakes (surface water from the river, water from infiltration wells, treated water directed to the water supply system) and additionally as a result of using bottled water. The present study analysed the content of 33 elements in water, grouped into microelements, ultratrace elements and other elements found in the aquatic environment. The majority of those elements are essential to proper human development and functioning. They can enter the human body together with water: (a) ingested directly, (b) present in food, (c) inhaled or (d) absorbed through skin. The results obtained were compared with the chemical composition of 29 types of bottled water (mineral and spring water) available in the retail market. Reference doses for each of the parameters were calculated in accordance with the US EPA guidelines and compared with the doses recommended in other research studies. Two water treatment plants (WTPs and WTPss) located in southern Poland were selected as research facilities. Water treatment plants treat surface water from rivers and groundwater from infiltration wells using sand filters. It was found that the average mineralisation of water supplied in the water distribution system ranges from 0.15 to 0.2 mg dm-3, which indicates that it has characteristics of natural low-mineral spring water. It provides 0.0001%-0.0003% of the recommended daily intake (RDI) for Al, As, Cd, Co, Cr, Cu, Mn, Mo, Ni, P, and Sn for children and for adults. The novelty of the article is the determination of the doses of microelements in bottled water. Bottled mineral water provides considerably higher doses of microelements than the values stemming from the RDI. The delivered doses of carcinogenic and potentially carcinogenic elements are of particular importance. In the case of Al, Cr, and Ni, the total recommended dose was exceeded 1 to 2 times for children and 1.5-7 times for adults. It was demonstrated that consumers should be careful about drinking water with an elevated content of microelements that are characterized by a very small, yet critical difference between the reference dose and the recommended dose. [ABSTRACT FROM AUTHOR]

Background: The Nile River included diverse phytoplankton compositions belonging to five main phytoplankton categories. Algae have been classified and identified through comparative morphology. Results: The Pyrrophyta, Charophyta, Cyanophyta, Chlorophyta, and Bacillariophyta were presented through the full period of investigation with 1, 3, 14, 23, and 28 species, respectively. Therefore, it may be important to note that diatoms were recorded as an abundant group in all investigated samples. The numbers of diatoms ranged between 1.45 × 106 and 1.18 × 107 Organism/l, this was followed by green algae that ranged from 7.0 × 105 to 1.22 × 106 Organism/l. While the lowest count of blue-green algae was ranged between 1.6 × 105 and 7.03 × 105 Organism/l. The treatment of Nile water using two chemical coagulants "aluminum sulfate (Al2(SO4)3⋅16H2O) and aluminum oxide (Al2O3)" removed algae by about 85% and 90%, respectively. As for, the Cyanophyceae species, they were removed completely in treated water using the sedimentation, filtration, and chlorination process. The sedimentation basins removed from 20 to 100% of the total algal count while the rapid sand filters removed from 65 to 100% of the total algal count during the water treatment that depends on the species of algae. Conclusions: This study concluded that the removal of algae from the Nile water may be more or less easy depending on the nature of the prevailing algal group. Water treatment plants must modify alum and chlorine doses in their water treatment processes according to the count and species of the algal groups, to provide an aesthetically acceptable and biologically safe water supply. [ABSTRACT FROM AUTHOR]

Approximately 99.1% of South Koreans have access to drinkable tap water from river basins. Due to such a high access rate, the South Korean government has been running, since 2013, a long-term program for monitoring the quality of tap water for drinking. Under this program, the maximum allowed concentrations of N-nitroso-di-n-methylamine (NDMA) and N-nitrosomethylethylamine (NMEA) are defined and applied. In this study, the data from this monitoring program were used to investigate the changes in six N-nitrosamine substances in the finished water of 33 drinking water treatment plants (DWTPs) in South Korea from 2013 to 2020, based on time and location. The effect of the applied water treatment steps on the appearance of N-nitrosamines was analyzed. The excess cancer risk (ECR) due to the oral intake of these substances was assessed. The results before the maximum allowed concentrations of NDMA and NMEA were defined showed that the oral intake ECR of these substances exceeded the carcinogenesis risk of one per one million people per year. After the maximum allowed concentrations of the substances were applied, the concentrations of the substances in the finished water of the DWTPs significantly dropped. The drinking water treated through sand filtration, and then with granular activated carbon, showed the highest efficiency in preventing the appearance of NDMA. Considering the potency of N-nitrosamines in tap water for drinking, the levels of these substances in the finished water of DWTPs in South Korea should be continuously monitored. [ABSTRACT FROM AUTHOR]

This study investigates the capability of a Bacillus flexus strain isolated from decayed cyanobacterial blooms for the bioremediation of Cylindrospermopsis raciborskii and cylindrospermopsin (CYN) toxin. The algicidal activity of this strain was tested by co-cultivation with C. raciborskii cultures. CYN biodegradation was investigated in the presence of living and heat-inactivated bacterial cells or bacterial filtrate. Living bacterial cells inhibited C. raciborskii growth after 2 days of incubation with complete cell death at day 5. Bacterial filtrate caused a rapid reduction in C. raciborskii growth at the first day, with complete cell lysis at day 3. Only living cells of SSZ01 caused reduction in CYN released into the medium during the bacterial decay of C. raciborskii cells. The biodegradation rate of CYN by SSZ01 relied on initial toxin concentrations. The highest rate (42 μg CYN L−1 day−1) was obtained at the higher initial concentration (300 μg L−1), and the lowest (4μg CYN L−1 day−1) was at lower concentration (50 μg L−1). These results suggest that this bacterial strain could be employed to bioremediate cyanobacterial blooms in freshwaters. Also, the application of this bacterium in slow sand filters would give possibilities for degradation and bioremediation of cyanotoxins in drinking water treatment plants. [ABSTRACT FROM AUTHOR]

Drinking water treatment techniques are used globally in the context of water security and public health, yet they are not applicable to antibiotic resistance gene (ARG) contamination. Using high-throughput quantitative PCR, we analyzed the prevalence and diversity of ARGs and mobile genetic elements (MGEs) in water supplies. A total of 224 ARGs and MGEs were detected in all sampling sites. Absolute abundance and detected number of ARGs decreased significantly (P < 0.05) in sand filter water after drinking water treatment and increased thereafter at point-of-use (household tap water). Changes in the composition and diversity of the bacterial community were observed in water samples at different steps. A significant correlation (P < 0.001) between microbial communities and ARG profiles was observed, and variance in ARG profiles could be primarily attributed to community composition (11.9%), and interaction between community composition, environmental factors and MGEs (30.7%). A network analysis was performed, and the results showed eight bacterial phyla were significantly correlated with nine different classes of ARGs, suggesting the potential bacterial host for ARGs. This study suggested that although the absolute abundance of ARGs decreased after treatment of drinking water treatment plants (DWTPs), the rebounded of ARGs in the water distribution system should not be neglected. [ABSTRACT FROM AUTHOR]

This work aims to study the technical problems of algal blooms that hinder the purification process of surface water used for drinking purposes and not its harmful effect on human health and the surrounding environment. It is also related to the demonstration of the improved coagulation process as an efficient technique in the algal removal from surface water by its application in jar tests. The study was carried out in the water purification plant in Nazlet Abdellah near the city of Assiut, Egypt. To achieve that, many ores and natural materials which aid in the removing of the algal blooms from surface water during the purification processes were tested. The examined materials should be technically and economically proper for improving the removal of algae from treated surface water for drinking purposes. The results showed that the kaolinite and bentonite (K and B) when coupled separately with aluminum sulfate (alum.) (the main coagulant agent) associated with the raw surface water in the flocculation basin were more efficient in the algae removal from treated surface water before reaching the sand filters by ratio up to 90%. [ABSTRACT FROM AUTHOR]

The ultimate object of this study is the replacement of the precipitator plus the rapid sand filter (RSF) used in the conventional water treatment plant (WTP) with single filtration equipment. The pore controllable fiber (PCF) filter which was one of the depth filters using the pump pressure was studied from 2008 to apply to the portable water production. In this study, the PCF was improved by thickening the filter media depth more than 2 times and adjusting the backwash conditions. The feed used in the main study was supplied from the Hoedong catchment of which hydraulic retention time was about 14 d. So, its average turbidity was very low as much as about 5.76 NTU and its particle size was very fine as much as about 8 μm by weight average since it was naturally precipitated for 14 d. The purpose of this study is to discuss problems and to find solutions through performance tests of the improved PCF (let 150 mm PCF) for the WTP process. According to pilot test results, the filter showed more than 99% removal of the turbidity and so the turbidity of the filtrate was as low as 0.066 NTU after increasing the filter media depth to 150 mm even though the raw water’s turbidity was as low as 8.97 NTU. Moreover, a similar pilot which was tested on the raw water of the Nacdong river for 2 months from June of 2020 showed that the filtrate turbidity was 0.065 NTU and 99.7% of the turbidity was removed from 24.9 NTU of the feed. These results hint that the PCF could be in a fair way to replace the conventional WTP in the near future. According to the performance data for nine equipment including the PCF and seven of UF membranes evaluated by BWQI that was the public organization of Busan city, Korea from to June 24 to September 17 of 2018, the PCF having 100 mm filter media depth (let 100 mm PCF) was lower than the UF by 0.3% in the turbidity removal but was higher than the UF by 11%, 22.7%, and 20% in dissolved organic carbon, Mn, and trihalomethane formation potential removal, respectively. On the other hand, results of SDI15 measurements that were the indirect indicator for colloidal showed 3.3 for the PCF and 2.3 for 6 of the UF by average which were satisfying the RO pre-treatment standard, 5.0 as the colloidal level. The colloidal removal of the 100 mm PCF was slightly worse than membranes through the comparison of the turbidity removal and the SDI15 between the 100 mm PCF and membrane. It was found that these problems were coming from the initial filtrate of the PCF. So, it was concluded that the circulation of the initial filtrate of the PCF to the feed is needed to obtain higher colloidal removal from the PCF, and it is expected that this work makes the colloidal removal of the PCF close to the membrane. [ABSTRACT FROM AUTHOR]

The emergency water treatment technology supplies water when the quality of raw water becomes temporarily unpleasant due to an incident. Removing the factors producing turbidity is very important because of different issues, such as protecting microorganisms during disinfection. Thus, it is one of the priorities of water treatment in emergency conditions. The present study aimed at surveying the function of tube settlers in water treatment, especially for removing turbidity, in emergency conditions. This cross-sectional study was done by making a pilot using polyvinyl chloride material and a sedimentation tank as the control pilot. The performance of these settlers was surveyed during three different steps; without using any coagulants, using coagulants, and using coagulants and a slow sand filter. The efficiency of the tube and the control pilot were surveyed at three inlet turbidities (100, 200, and 300 NTU) at 10, 20, and 30 min retention times in each of the three steps. The samples were gathered from designated places according to the above-mentioned retention times. The best efficiency was gained at 300 NTU inlet turbidity and 30 min retention time. The average efficiency was 45.3% for the control pilot, 89.9% for the tube pilot using coagulants, 57.2% for the tube pilot without using any coagulants, and 99.4% for the tube pilot using coagulants and a slow sand filter. The results demonstrated the high efficiency of the tube pilot in removing turbidity compared to the control pilot. [ABSTRACT FROM AUTHOR]

Optimizing nanoplastics (NPs) removal performance of rapid sand filter (RSF) in water treatment plants is significant for NP pollution prevention and remediation. This study investigated the application prospect of natural granular manganese sand, zeolite and limestone in RSF for NP removal through column experiments. Pristine, amino-modified, and carboxyl-modified polystyrene NPs (100 nm) were selected as experimental subjects. Quartz sand filter showed negligible NP removal, zeolite and manganese sand showed no obvious optimization on NP filtration. Limestone amended RSF significantly enhanced the removal of three NPs, the removal efficiency increased with decreasing size and increasing limestone grains dosage. The excellent performance of limestone was attributed to its special physicochemical properties in terms of synthetical action of electrostatic interaction, cationic bridging and especially the surface roughness morphology, and the mechanisms overcame the influence of functional groups of NPs. The results indicate the prospective applications of granular limestone in RSF for NP filtration. [Display omitted] • The removal of nanoplastics (NP) by quartz sand, zeolite and manganese sand can be ignored. • Limestone optimization significantly improved NP removal efficiency of sand filter. • Removal of NPs by limestone increased with decreasing particle size and increasing dosage. • NP removal mainly relied on filter chemical composition and roughness morphology. • Limestone offers application prospect in removal of NP with different functional groups. [ABSTRACT FROM AUTHOR]

Groundwater is a viable alternative when access to surface water resources is limited. Iron and manganese are known ions in soil and naturally in groundwater sources. However, human activities also are responsible. To identifying the best module for removing manganese and iron in the water treatment plant (WTP) of Mazandaran, 516 samples were taken from raw and treated water. The concentration of manganese, iron, was measured by atomic absorption spectrophotometry, and turbidity was used with the nephelometry method. The water pollution index (WPI) was applied for categorizing the status of pollution in treated water. The effect of seasonal temperature and backwashing (At flow rates of 3.5, 9.2, and 15.3 m h-1) on the sand filter efficiency was also investigated. The highest concentrations of manganese, iron, and turbidity in raw water were 0.744, 6.70 mg L-1, and 41.8 NTU, and in treated water were 0.67, 1.09 mg L-1, and 5.58 NTU, respectively. The mean concentration of manganese and iron in raw and treated water were 0.24 ± 0.1, 0.93 ± 0.91, 0.105 ± 0.06 and 0.18 ± 0.14 mg L-1 respectively. The WPI statuses in drinking water were excellent for manganese and iron in 95.74 and 53.88 % of the samples and very poor in 1.16 and 12.01 % of the samples, respectively, and its classification for drinking water for manganese and iron was excellent ˃ good ˃ extremely polluted ˃ polluted and the concentration of iron was more than manganese in treated water. The study of temperature's effect on sand filters showed that the removal efficiency in warm seasons was higher than in cold seasons. Also, the turbulence in the backwash with the 9.2 m h− 1 rates, is lesser than other speeds, and in this flow, after 270 s, the turbidity decreases to less than 10 NTU. Spearman correlation comparison showed that the parameters amounts after filtration decreased significantly (p ≤ 0.0001) in comparison to raw water. The results showed that module #1 that used open-aeration and chlorine as oxidations, was most effective in removing iron and manganese. In the end, the WTP couldn't diminish the parameters completely and need subsidiary units. [ABSTRACT FROM AUTHOR]

• Degradation of antibiotics mediated by MnOB was achieved through a biofilter. • The secondary pollution caused by the feeding manganese could be avoided. • The growth of MnOB group at antibiotics range of 50-1000 ng/L was studied. • The biofilter did not generate additional antibiotic resistance gene. Antibiotic micro-pollution is usually found at the ng/L–level in drinking water sources or discharge water of wastewater treatment plants. In this study, a novel approach mediated by manganese oxidizing bacteria (MnOB) in a biofilter was developed to control the pollution. The results indicated that the biogenic manganese oxide (MnO x) produced during the oxidation of the feeding manganese ions could coat the surface of the filtering sand effecting the simultaneous removal of antibiotics. It was found that the removal of antibiotics is insured as long as the feeding manganese was well removed and was not influenced by the hydraulic loading. The growth rate of the MnOB group revealed that the antibiotic concentration at 50 and 100 ng/L promoted their activity, but it was inhibited at 500 and 1000 ng/L. The structure of the bacterial community was stable in the presence of antibiotics (50 ng/L), but their extracellular processes changed. The removal performance of the feeding manganese seemed to relate to the extracellular processes of the dominant bacterial genus. Moreover, the freshly formed MnO x was a buserite-like material that was rich in Mn(III) and Mn(IV) (94.1%), favoring the degradation. The biofilter did not generate additional antibiotic resistant genes in the presence of antibiotics. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Nitrification is important in drinking water treatment plants (DWTPs) for ammonia removal and is widely considered as a stepwise process mediated by ammonia- and nitrite-oxidizing microorganisms. The recent discovery of complete ammonia oxidizers (comammox) has challenged the long-held assumption that the division of metabolic labor in nitrification is obligate. However, little is known about the role of comammox Nitrospira in DWTPs. Here, we explored the relative importance of comammox Nitrospira , canonical ammonia-oxidizing archaea (AOA) and bacteria (AOB) in 12 surface water-fed rapid sand filters (RSFs). Quantitative PCR results showed that all the three ammonia-oxidizing guilds had the potential to dominate nitrification in DWTPs. Spearman's correlation and redundancy analysis revealed that the surface ammonium loading rate (SLR) was the key environmental factor influencing ammonia-oxidizing communities. Comammox Nitrospira were likely to dominate the nitrification under a higher SLR. PCR and phylogenetic analysis indicated that most comammox Nitrospira belonged to clade A, with clade B comammox Nitrospira almost absent. This work reveals obvious differences in ammonia-oxidizing communities between surface water-fed and groundwater-fed RSFs. The presence of comammox Nitrospira can support the stability of drinking water production systems under high SLR and warrants further investigation of their impact on drinking water quality. [ABSTRACT FROM AUTHOR]

The Kafr El-Sheikh Water Plants in Egypt, which are treating River Nile water, are confronted with high consumption of water for backwashing the rapid sand filters and elevated levels of turbidity in the effluent of the clarifiers and sand filters. It turned out that these problems are connected with the formation of foam layers in the clarifiers. The appearance of foam layers is attributed to the formation of tiny “air bubbles” in the water entering the clarifiers, resulting in the flotation of the sludge particles. Tiny “air bubbles’’ are most likely formed due to supersaturation with air and/or oxygen of the raw water. Supersaturation might occur in the open channels through which the raw water travels over the long distances from the Nile to the plants. Such a supersaturation with air might be caused by increasing the temperature during the journey of the raw water and/or the growth of algae, which use to produce oxygen during day time. To mitigate the problems due to the formed sludge layers, low-cost gutters, and sprinkler devices are installed. These measures resulted in a substantial reduction of the consumption of water for backwashing the rapid sand filters and improved turbidity of the effluent of the clarifiers and filters. [ABSTRACT FROM AUTHOR]

The characteristics and composition of dissolved organic matter (DOM) and trihalomethane (THM) generation during water treatment are important for producing safe drinking water. However, little information is available on this topic within the context of Indonesia. This study aimed to investigate the efficiency of a conventional drinking water treatment plant (WTP) in removing DOM and chloroform forming potential (CHCl3FP), and evaluate surrogate parameters for CHCl3FP. Samples were taken during the rainy season and the dry season from raw water, after secondary treatment and after the rapid sand filter. DOM was characterized based on the A254, A355, SUVA, dissolved organic carbon (DOC), and fluorescence DOM (FDOM) parameters. The composition of the DOM was identified using the peak picking method. Overall, from raw to finished water, the WTP performed better in the rainy season with 55.96% reduction of DOC and 63.45% reduction of A355 as compared to the dry season with 53.27% reduction of DOC and 24.18% reduction of A355. The overall removal of humic and tryptophan compounds during the rainy season was 33.33% and 37.50%, respectively. In the dry season, humic compounds were reduced by 18.80%, while tryptophan increased threefold. A355 can serve as a surrogate parameter for CHCl3FP in raw water and water after secondary treatment, containing more humic-like compounds than tryptophan-like compounds. [ABSTRACT FROM AUTHOR]

Water management in oil and gas production industries is one of the important issues due to the requirement of huge amount of freshwater in process and generation of large amount of waste stream called produced water (PW), which is 70 % of total wastewater. Due to the PW is the largest waste stream generated from oil and gas production process, the recycle of produces water can reduce the supply of freshwater from other sources of water such as river and lake, and negative influence on environment caused by water intake and disposal of the PW. In order to recycle/reuse the PW, it is commonly treated by physical, chemical and biological methods such as adsorption, flotation, sand filter, evaporation, electrodialysis and membrane-based processes. This review focuses on the research state of conventional and emerging technologies for water management in oil sands field for treatment of PW. It also addresses the real water management strategies in oil sands plant in Canada. The new strategies for water management are discussed through the comparative analysis on the current state of technologies and strategies. • The status of water management and produced water treatment in oil sands plant was reviewed. • Produced water treatment is inevitable to mitigate problems on freshwater supply and environment. • Membrane shows good performance to remove the contaminants in produced water with high water quality. • Control of the negative effects of scalants is essential for proper water management with high water recovery. [ABSTRACT FROM AUTHOR]

The article discusses news and information on biological filtration, or biofiltration, in drinking water treatment. Topics mentioned include advancement of biofiltration science and engineering for surface water treatment facilities, the establishment of the Biological Drinking Water Treatment Committee in 2008 by the American Water Works Association, and development of a Biofiltration Focus Area by the Water Research Foundation to advance biofiltration research.

Microbiological risks associated with drinking water can be minimized by providing enhanced integrity monitoring of bacterial removal by water treatment processes. This study aimed to evaluate the efficacy of real-time bacteriological counters for continuously assessing the performance of a full-scale sand filter to remove bacteria. Over the course of an 8-day evaluation, online counting of bacteria was successfully performed, providing continuous bacterial counts in the sand filter influent and effluent over approximate ranges from 17 × 104 to 94 × 104 and from 0.2 × 104 to 1.3 × 104 counts/mL, respectively. Periodic variations were observed with online bacterial counts in the sand filter influent because of the changes in the performance of flocculation and sedimentation processes. Overall, online removal rates of bacteria determined during the full-scale test were 95.2–99.3% (i.e., 1.3–2.2-log), indicating that online bacterial counting can continuously demonstrate over 1.3-log removal in the sand filter. Real-time bacteriological counting technology can be a useful tool for assessing variability and detecting bacterial breakthrough. It can be integrated with other online water quality measurements to evaluate underlying trends and the performance of sand filters for bacterial removal, which can enhance the safety of drinking water. Image 1 • Performance of a full-scale sand filter for bacterial removal was evaluated. • Online counting of bacteria in the filter influent and effluent was performed. • Periodic variations were observed with online bacterial counts. • Online removal rates of bacteria determined during the evaluation were over 1.3-log. [ABSTRACT FROM AUTHOR]

Sand filters (SFs) are commonly applied in drinking water treatment plants (DWTPs) for removal of iron and manganese but also show potential for microbial degradation of pesticide residues. The latter is advantageous in case the intake water contains pesticide residues. However, whether this involves mineralization suggesting no generation of harmful transformation products, its consistency over time, and how this ability relates to physicochemical and biological characteristics of the DWTP intake water and the SFs is unknown. The capacity to mineralize the herbicides bentazon and 2-methyl-4-chlorophenoxyacetic acid (MCPA) was examined in SF samples from 11 DWTPs differing in operation, intake water composition and pesticide contamination level. MCPA was mineralized in all biologically active SFs while mineralization of bentazon occurred rarely. Mineralization of both compounds was consistent in time and across samples taken from different SF units of the same DWTP. Kinetic modelling of mineralization curves suggested the occurrence of growth linked bentazon and MCPA mineralization in several SF samples. Multivariate analysis correlating intake water/SF characteristics with pesticide mineralization indicated that pesticide mineralization capacity depended on a range of intake water characteristics, but was not necessarily explained by the presence of the pesticide in the intake water and hence the in situ exposure of the SF community to the pesticide. This was supported by testing a sample from DWTP Kluizen for its capacity to mineralize 5 other pesticides including pesticides not present or occasionally present in the intake water. All of those pesticides were mineralized as well. • Microbial communities in SFs of DWTPs mineralize pesticide residues. • MCPA was readily mineralized in all biologically active SFs. • Bentazon was rarely mineralized, but its mineralization capacity was consistent. • Pesticide mineralization capacity cannot be explained by the in situ exposure of the SF community to the pesticide. [ABSTRACT FROM AUTHOR]

The paper presents the examples of damage of elements caused by incorrect assessment of pipeline work conditions. The presented damage cases resulted in the need to replace pipelines. This work is an analysis pertaining to the impact of chemical and microbiological synergy of corrosion on stainless steel pipelines. The paper investigates the corrosion mechanisms that may occur under normal operating conditions at each water treatment station, and the methods of counteracting the corrosion were indicated. The analysis of the corrosion mechanisms was formulated taking into account the design stage, - the correctness of the steel grade choice by the designer, the stage of implementation - the most common implementation errors, and the operational stage - optimization of the technological system work and the effects of the introduced changes. The analysis was carried out at a water treatment plant in Poland with a maximum flow of 20,000 m3 a day-1, which draws raw water from deep water intakes and from a surface intake. The treatment technology includes an aeration system (aeration) and a two-stage treatment process using sand and carbon filters. The disinfection process and prophylaxis in the water treatment plant is based on the use of chlorine gas. [ABSTRACT FROM AUTHOR]

• A pilot-scale NF system was investigated for conventionally treated surface water. • Effective TOC removal was obtained to reduce taste and odor problem. • Loose NF was found more effective for end user health and preventing pipeline corrosion. • Tight NF was found more economic. • Cost analysis was done for upgrading the conventional water treatment plant. Natural organic matter (NOM) is responsible for a variety of problems in water, including taste, odor, and color. If NOM is present in treated water, it can also promote microbial growth in water distribution systems. Another problem related with NOM is that it combines with chemicals such as chlorine in water resulting in the formation of disinfection by-products (DBPs). With the DBP regulations becoming more stringent, several advanced treatment methods started to be applied to enhance NOM removal. Pilot-scale advanced treatment tests employing tight nanofiltration (T-NF) membrane with high ion rejection capacity and loose nanofiltration (L-NF) membrane with low ion rejection capacity were conducted in this study in order to remove total organic carbon (TOC) having an average concentration of 2 mg/L at the sand filter effluent of a full-scale drinking water treatment plant and to avoid DBP production. The cost of incorporating membrane processes into the treatment process scheme was also determined during the study, in addition to the experimental studies. At constant 6 bar, the average fluxes for the T-NF and L-NF were determined to be 12.7 and 7.6 L /m2 h, respectively. L-NF had a TOC removal efficiency of 96.0%, which is quite similar to the removal efficiency achieved by T-NF (96.3%). Heavy metals, anions, and cations removal efficiency in T-NF membranes were greater than in L-NF, as expected. The removal efficiencies of Cl-, and Fe on T-NF membrane were determined to be 90.3 ± 2.2% and 69.6 ± 5.6, respectively, which are much greater than those achieved in L-NF membrane The total cost of 400,000 m3/d L-NF membrane system upgrade is calculated as 28,901,262 $/y including capital and operation and maintenance (O&M) costs, while in T-NF is calculated as 28,074,282 $/y. The total cost of NF upgrading is estimated to be around 0.191–0.198 $/m3, which is nearly 50% of the cost of the conventional treatment plant. When upgrading a conventional treatment system with this type of membrane system, additional expenses are typically incurred, resulting in a higher total cost; however, the resultant water quality is significantly improved. [ABSTRACT FROM AUTHOR]

[Display omitted] • UF outperforms sand filters and ensures water safety under critical conditions. • Fouling was reduced and the arsenic retention was improved with an in-line dose. • NOM builds up in the treatment process when UF concentrate is recycled. • UF permeate obtained in the pilot scale attained all potable standards analyzed. • UF integration to WTPs is a solution to improve water treatment resilience. There is a growing interest in advanced technologies to guarantee drinking water safety in scenarios of increasingly polluted water sources. Based on that, this paper discusses the use of ultrafiltration membranes aided by in-line coagulation with FeCl 3 (0.086 – 0.172 mg/L) to improve the resilience of drinking water treatment plants. The process was considered after the settling units and was first studied on a bench scale, later validated in a pilot plant that operated continuously for approximately 31 days. In experiments without an in-line dose of FeCl 3 , the average flux values corresponded to 189.9 ± 11.8 L/m2h, compared with 193.4 ± 5.3 L/m2h for experiments when the coagulant was considered. The flux decay was lower in experiments with an in-line dose of FeCl 3 (J/J 0 > 0.95) and analysis of particle sizes revealed that the average diameter increased from 24.1 to 29.2 µm after the coagulant was added. Consequences related to a greater particle size were a fouling layer more porous permeable, and with a lower hydraulic resistance. The additional coagulant dosage also acts on the residual natural organic matter, monitored by excitation-emission matrices. Furthermore, the results show that the concentrate recirculation to the beginning of the water treatment plant did not affect its overall performance. In fact, concentrate recycling would increase the recovery rate of ultrafiltration membranes and reduce losses during water treatment. Similar observations were obtained in pilot-scale operations, that validated the in-line dose on a more representative system that is closer to the full-scale treatment process. [ABSTRACT FROM AUTHOR]

Here, we evaluated the removal of three representative human enteric viruses — adenovirus (AdV) type 40, coxsackievirus (CV) B5, and hepatitis A virus (HAV) IB — and one surrogate of human caliciviruses — murine norovirus (MNV) type 1 — by coagulation–rapid sand filtration, using water samples from eight water sources for drinking water treatment plants in Japan. The removal ratios of a plant virus (pepper mild mottle virus; PMMoV) and two bacteriophages (MS2 and φX174) were compared with the removal ratios of human enteric viruses to assess the suitability of PMMoV, MS2, and φX174 as surrogates for human enteric viruses. The removal ratios of AdV, CV, HAV, and MNV, evaluated via the real-time polymerase chain reaction (PCR) method, were 0.8–2.5-log 10 when commercially available polyaluminum chloride (PACl, basicity 1.5) and virgin silica sand were used as the coagulant and filter medium, respectively. The type of coagulant affected the virus removal efficiency, but the age of silica sand used in the rapid sand filtration did not. Coagulation–rapid sand filtration with non-sulfated, high-basicity PACls (basicity 2.1 or 2.5) removed viruses more efficiently than the other aluminum-based coagulants. The removal ratios of MS2 were sometimes higher than those of the three human enteric viruses and MNV, whereas the removal ratios of φX174 tended to be smaller than those of the three human enteric viruses and MNV. In contrast, the removal ratios of PMMoV were similar to and strongly correlated with those of the three human enteric viruses and MNV. Thus, PMMoV appears to be a suitable surrogate for human enteric viruses for the assessment of the efficacy of coagulation–rapid sand filtration to remove viruses. [ABSTRACT FROM AUTHOR]

The aim of this work was to assess the suitability of matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) for routine heterotrophic monitoring in a drinking water treatment plant. Water samples were collected from raw surface water and after different treatments during two campaigns over a 1-year period. Heterotrophic bacteria were studied and isolates were identified by MALDI-TOF MS. Moreover, the diversity index and the coefficient of population similarity were also calculated using biochemical fingerprinting of the populations studied. MALDI-TOF MS enabled us to characterize and detect changes in the bacterial community composition throughout the water treatment plant. Raw water showed a large and diverse population which was slightly modified after initial treatment steps (sand filtration and ultrafiltration). Reverse osmosis had a significant impact on the microbial diversity, while the final chlorination step produced a shift in the composition of the bacterial community. Although MALDI-TOF MS could not identify all the isolates since the available MALDI-TOF MS database does not cover all the bacterial diversity in water, this technique could be used to monitor bacterial changes in drinking water treatment plants by creating a specific protein profile database for tracking purposes. [ABSTRACT FROM AUTHOR]

The comprehensive control efficiency for the formation potentials (FPs) of a range of regulated and unregulated halogenated disinfection by-products (DBPs) (including carbonaceous DBPs (C-DBPs), nitrogenous DBPs (N-DBPs), and iodinated DBPs (I-DBPs)) with the multiple drinking water treatment processes, including pre-ozonation, conventional treatment (coagulation–sedimentation, pre-sand filtration), ozone-biological activated carbon (O 3 -BAC) advanced treatment, and post-sand filtration, was investigated. The potential toxic risks of DBPs by combing their FPs and toxicity values were also evaluated. The results showed that the multiple drinking water treatment processes had superior performance in removing organic/inorganic precursors and reducing the formation of a range of halogenated DBPs. Therein, ozonation significantly removed bromide and iodide, and thus reduced the formation of brominated and iodinated DBPs. The removal of organic carbon and nitrogen precursors by the conventional treatment processes was substantially improved by O 3 -BAC advanced treatment, and thus prevented the formation of chlorinated C-DBPs and N-DBPs. However, BAC filtration leads to the increased formation of brominated C-DBPs and N-DBPs due to the increase of bromide/DOC and bromide/DON. After the whole multiple treatment processes, the rank order for integrated toxic risk values caused by these halogenated DBPs was haloacetonitriles (HANs) ≫ haloacetamides (HAMs) > haloacetic acids (HAAs) > trihalomethanes (THMs) > halonitromethanes (HNMs) ≫ I-DBPs (I-HAMs and I-THMs). I-DBPs failed to cause high integrated toxic risk because of their very low FPs. The significant higher integrated toxic risk value caused by HANs than other halogenated DBPs cannot be ignored. [ABSTRACT FROM AUTHOR]

Cyanobacterium Cylindrospermopsis raciborskii may cause problems in drinking water treatment plants if specific attention is not focused on removing the cyanobacteria. Slow sand filtration possesses a good capacity for cyanobacteria removal and is a simple alternative to more expensive treatments. However, high cyanobacteria concentrations can correspond to an operational problem for slow sand filters by reducing the filter running time, and therefore rough filtration is necessary. In this study, two similar upflow slow sand filters were used to evaluate C. raciborskii removal. Water with 9.1 × 105 cells/mL was used and an average of 99% of cells were removed. Nevertheless, average concentrations of 1.4 × 104 and 2.1 × 104 cells/mL were observed after filtration, and this could continue to act as a problem for water treatment. The system also indicated good results in terms of removing total coliforms, colour and turbidity. The average turbidity was below 1.0 NTU, which is the maximum value permitted by Brazilian regulations and WHO recommendations. The major advantage of the upflow slow sand filter involved the high removal of C. raciborskii without compromising the running time of the filter with the filters operating for almost 80 days without the use of rough filters. However, it is necessary to use a complementary treatment process to achieve better water quality results. [ABSTRACT FROM AUTHOR]

This study presented performance data on a low cost and easy maintenance pilot system for on-site treatment and reuse of water collected from wash sinks and fountains, as major sources of greywater (GW) at schools. Various treatment options were studied including screening, sand filtration, chlorination, and UV disinfection operated at different flow rates. Results showed that filtration operated at low rates is very effective in total suspended solids (TSS) removal, while UV proved to be more effective than chlorination for reduction of biochemical oxygen demand (BOD), chemical oxygen demand (COD), and total coliforms. Removal efficiencies up to 63%, 30% and 20% were obtained for TSS, COD and BOD, respectively and reductions of log TC (CFU/100 ml) from 6.5 to 2 were obtained at a filtration rate of 14 m³/d·m². Treated effluent satisfied WHO standards for reclaimed water reuse in landscape irrigation and toilet flushing. The filtration-UV system is robust, showing the best and most reliable performance for low and high strength GW treatment even under a 10-fold increase in flow rate. A 5 m³/d pilot plant was developed for schools having 500 students and detailed cost-benefit analysis indicated a net saving value, a surplus of $1,600 per year, and pay back after 6 years and 11 months. [ABSTRACT FROM AUTHOR]

• Single dual- and consecutive single-media filters are eco- and operationally equivalent. • Both systems exhibited comparable performances and process compartmentalization. • Media coating and genome-based composition were homogeneous in each compartment. • Only protein abundances reflected stratification in activity. • Backwash shapes microbial community distribution in rapid sand filters. Rapid sand filters (RSF) are an established and widely applied technology for groundwater treatment. Yet, the underlying interwoven biological and physical-chemical reactions controlling the sequential removal of iron, ammonia and manganese remain poorly understood. To resolve the contribution and interactions between the individual reactions, we studied two full-scale drinking water treatment plant configurations, namely (i) one dual-media (anthracite and quartz sand) filter and (ii) two single-media (quartz sand) filters in series. In situ and ex situ activity tests were combined with mineral coating characterization and metagenome-guided metaproteomics along the depth of each filter. Both plants exhibited comparable performances and process compartmentalization, with most of ammonium and manganese removal occurring only after complete iron depletion. The homogeneity of the media coating and genome-based microbial composition within each compartment highlighted the effect of backwashing, namely the complete vertical mixing of the filter media. In stark contrast to this homogeneity, the removal of the contaminants was strongly stratified within each compartment, and decreased along the filter height. This apparent and longstanding conflict was resolved by quantifying the expressed proteome at different filter heights, revealing a consistent stratification of proteins catalysing ammonia oxidation and protein-based relative abundances of nitrifying genera (up to 2 orders of magnitude difference between top and bottom samples). This implies that microorganisms adapt their protein pool to the available nutrient load at a faster rate than the backwash mixing frequency. Ultimately, these results show the unique and complementary potential of metaproteomics to understand metabolic adaptations and interactions in highly dynamic ecosystems. [Display omitted] [ABSTRACT FROM AUTHOR]

Recently, seasonal manganese contamination in the surface water is capturing ever-increasing attention and has posed significant challenges to the safety of water supply in the conventional drinking water treatment plants. This study aimed to develop new strategies to enhance the manganese removal by the sand filter. The synergistic effects of filter material type, filter layer thickness, filtration rate, and NaClO addition on the manganese removal performance, were systematically investigated. The results indicated that modified zeolite exerted the highest adsorption capacity (5.200 mg/g) for manganese. Introducing the NaClO oxidation would effectively improve the manganese removal efficiency (from 32 % to 97 %) by the modified zeolite filter compared to the control system at the filtration rate of 8 m/h, owing to the fast formation of catalytic oxidation capability. Accordingly, the effective layer thickness of modified zeolite can be shortened from 100 cm to 10–20 cm to engineer a double-layer filter consisting of both a thin modified zeolite layer and a thick natural quartz sand layer. Besides, NaClO involvement would neutralize the adverse effects of manganese removal caused by the filtration rate increase, and facilitate the formation of auto-catalytic manganese oxides (MnOx) with rough, heterogeneous, and porous surface morphology, as well as numerous tremella-like and sponge-type structures, which was related to the fast removal of manganese. These findings are full of significance in developing simple, practical, and cost-effective strategies for seasonal manganese contamination. [Display omitted] • A fast manganese removal method was proposed based on modified zeolite and NaClO. • NaClO involvement enhanced the fast generation of catalytic oxidation MnOx. • Engineer a double-layer filter of modified zeolite (10–20 cm) and natural quartz sand. • The removal pathway of Mn2+-MnO x - autocatalytic oxidation film was elucidated. • NaClO involvement can neutralize the adverse effects caused by filtration rate. [ABSTRACT FROM AUTHOR]

With dam failure events, there can be changes in water quality and difficulties in the operation of water treatment plants (WTPs) since they were not designed for water treatment under severe pollution conditions. To avoid that, it was investigated two strategies based on pre-oxidation, ultrafiltration (UF) and reverse osmosis (RO) integrated into a conventional treatment process (coagulation, flocculation, and sand filtration) or with each other, with the potential to reduce the risks of drinking water shortage and guarantee a safe drinking water supply. The study considered the context of the Velhas river basin (Brazil), where water quality is compromised by high turbidities (500–3000 NTU) and excessive arsenic (∼0.4 mg/L), iron (∼50 mg/L), and manganese (∼3 mg/L) levels. They were only partially removed by conventional treatments (removals: 74 ± 21%) and potability standards were only achieved after the membrane separation processes were considered (As: <0.01 mg/L, Mn: <0.1 mg/L, and Fe: <0.3 mg/L). The high water quality after RO enables its blend with the stream obtained after sand filters and would allow for greater flexibility during the operation of WTPs operation. Despite the susceptibility to fouling and most frequent maintenance, the pre-oxidation-UF-RO system would also guarantee a safe drinking water supply. The decision for the most adequate strategy was then based on a multicriteria analysis. A retrofit of conventional WTPs by their integration with UF-RO was classified as the best strategy for centralized facilities, whereas pre-oxidation-UF-RO better fits the reality of decentralized treatments given the lower costs and deployment time. The methodology based on multicriteria analysis and water treatment technologies, exemplified by membranes in this study, presented satisfactory results for different scenarios of critical treatment. [Display omitted] • RO guarantees safe drinking water even in scenarios of severe water quality deterioration. • Fouling was mostly reversible, and the membranes' integrity was not compromised after long-term operation. • UF membrane can retain colloids of As and Mn, different from sand-filter. • Variations in feed concentration of As and Mn do not compromise the RO permeate quality. • Provides quantitative/qualitative information for treatment decision making. [ABSTRACT FROM AUTHOR]

In order to properly assess and manage the risk of infection by enteric viruses in tap water, virus removal efficiency should be evaluated quantitatively for individual processes in actual drinking water treatment plants (DWTPs); however, there have been only a few studies due to technical difficulties in quantifying low virus concentration in water samples. In this study, the removal efficiency of indigenous viruses was evaluated for coagulation-sedimentation (CS) and rapid sand filtration (RSF) processes in a DWTP in Bangkok, Thailand by measuring the concentration of viruses before and after treatment processes using real-time polymerase chain reaction (qPCR). Water samples were collected and concentrated from raw source water, after CS, and after RSF, and inhibitory substances in water samples were reduced by use of a hydrophobic resin (DAX-8). Pepper mild mottle virus (PMMoV) and JC polyomavirus (JC PyV) were found to be highly prevalent in raw waters, with concentrations of 10 2.88 ± 0.35 and 10 3.06 ± 0.42 copies/L (geometric mean ± S.D.), respectively. Step-wise removal efficiencies were calculated for individual processes, with some variation observed between wet and dry seasons. During the wet season, PMMoV was removed less by CS and more by RSF on average (0.40 log 10 vs 1.26 log 10 , respectively), while the reverse was true for JC PyV (1.91 log 10 vs 0.49 log 10 , respectively). Both viruses were removed similarly during the dry season, with CS removing the most virus (PMMoV, 1.61 log 10 and 0.78 log 10 ; JC PyV, 1.70 log 10 , and 0.59 log 10 ; CS and RSF, respectively). These differences between seasons were potentially due to variations in raw water quality and the characteristics of the viruses themselves. These results suggest that PMMoV and JC PyV, which are more prevalent in environmental waters than the other enteric viruses evaluated in this study, could be useful in determining viral fate for the risk management of viruses in water treatment processes in actual full-scale DWTPs. [ABSTRACT FROM AUTHOR]

Biological water treatment using granular activated carbon (GAC) and anthracite improves water quality by reducing total organic carbon (TOC), colour, nitrogen content and turbidity. This study investigated the operation of aerobic biofilm on two pilot biofilters designed to remove turbidity, TOC, NO-3 and NH+ 4 in water. The results show that the GAC-sand pilot filter at a low hydraulic loading rate (HLR) increased the empty bed contact time and recorded the highest production of heterotrophic bacteria and biofilm, which increased the efficiency of treatment. Breakthrough occurred in the GAC-sand pilot filter at 72 h and low HLR, but occurred sooner for medium and high HLRs at 48 and 24 h, respectively. The run-time for the anthracite-sand pilot filter at high, medium and low HLRs was 70, 46 and 22 h, respectively. The microorganisms Pseudomonas, Bacillus and Citrobacter were identified in the GAC-sand filter. [ABSTRACT FROM AUTHOR]

Ozonation is known to be very effective in the removal of odorants from source water. However, it is not known if ozonation is effective in the removal of multiple odorants causing different types of odors. In this study, the removal performance for odors and odorants were evaluated in a Water Treatment Plant (WTP), which was equipped with coagulation, sedimentation, ozonation, biological activated carbon (BAC) filtration, sand filtration, and chlorination in succession and located in the downstream of the Huangpu (HP) River, over the period from April, 2014 to April, 2015. Flavor profile analysis (FPA) results showed that the source water was constantly associated with septic and musty odors. Geosmin and 2-MIB, with an average OAV of 4.54 and 1.38, respectively, were the major odorants for musty odor, while bis(2-chloroisopropyl) ether, DEDS and DMDS with an average OAV of 2.35, 1.65 and 0.78, respectively, might be responsible for the septic odor. While the musty odor could be removed effectively through the combination of ozonation and BAC, the septic odor and associated odorants required further treatment with sand filtration and chlorination for complete removal. It is clear that the advanced treatment process was effective for the treatment of source water containing complicated odorants. It should be noted that the sedimentation process needs careful management because release of odorants may occur during the treatment. The result of this study will be helpful for the mitigation of odors in WTP using source waters suffering from complicated odor problems. [ABSTRACT FROM AUTHOR]