Public Water Treatment Research Articles

Energy-saving Technology for Public Water Treatment Energy-saving Rotary Blower “TBS/RSH series”

地球の水問題を解決するための水資源開発，そして地球の環境保護や温暖化防止を目的とした温室効果ガスの削減の動きが世界的に高まりつつある中，水処理市場では，消費される電力量の約60％がロータリブロワを含む送風機によって消費されていることから，消費電力の削減が課題として浮彫となり，送風機の省エネが最重要課題となっている。そこで，当社では高い省エネ性と環境負荷軽減を実現させた新たなロータリーブロワ『TBS/RSH』シリーズの開発を行った。当該機ではインペラ形状に“RiS-brid曲線”を採用し，回転速度の最適化，サイレンサおよびギヤケースの改良などを行うことで，従来品から10～20％程度の省エネを達成することが出来た。2021年12月現在で300台以上の販売実績を数えており，新規購入だけでなく，置き換え案件の実績も多数有している。今後は水処理以外でも，空気輸送や燃焼空気源，製紙業の抄紙機用真空ポンプ，集じん用など様々な用途での使用が可能であるため，各種業界に省エネブロワを供給することで，広い分野で社会貢献をしていきたいと考えている。

Sustainable groundwater treatment technologies for underserved rural communities in emerging economies

Worldwide, about one out of two people depend on groundwater resources to satisfy their drinking water needs. While groundwater typically is of higher quality than surface water, pollution and geologic conditions may require treating groundwater to meet safe water quality criteria. Herein, a critical overview is presented of water treatment technologies for rural and underserved communities in emerging economies that depend on groundwater. Given that small to medium sized rural communities in emerging economies often lack the financial resources to support technologically complex and expensive centralized public water treatment systems, the focus is on proven technologies that are sustainable and acceptable by the rural population. After an overview of the underlying treatment mechanisms and the principal groundwater contaminants targeted by the traditional, advanced, and experimental water treatment technologies, we identify the groundwater quality parameters that may impact or interfere with the technology performance. We also introduce enabling environmental factors that might govern the implementation of water treatment technologies in the target communities and a brief discussion of safe storage of water after treatment to underline the importance of protecting the water from re-contamination. Our overview is further supported by tabulated summaries of the principal (dis)advantages of each technology covered herein, including cost considerations and social acceptance. Overall, our review suggests that underserved rural communities have sustainable and affordable options for cases where the quality of local groundwater resources requires treatment.

Overview of Heavy Metal Concentrations in Public Pipe Borne Water and Its Safety Implications for the Communities in Abuja Metropolis North-Central Nigeria

Heavy Metals (HM) are relatively dense metal or metalloid noted for its potential toxicity in the environment and these metals appear in the World Health Organization List of Chemicals of public health concern. Long-term exposure to HMs have been linked to slowly progressing physical, muscular and neurological degenerative processes in human that mimic Alzheimer’s disease, Parkinson’s disease, muscular dystrophy, multiple sclerosis, liver and kidney failures as well as alterations in gene expressions. This study assessed the concentration of some HM in public water supply in Abuja Metropolis from 2015 to 2016 with the view to determining its overall percentage compliance with the WHO(2008) recommended limits for drinking water quality . The HMs selected were aluminum (Al), iron (Fe), copper (Cu), and zinc (Zn) and manganese (Mn). A representative water samples from the six locations within the study area were collected and analyzed according to the Standard Methods and Procedures. Sampling regime took place three (3) times in each sampling month from which the monthly and annual mean values were obtained and analyzed statistically. The result indicated the following mean concentrations Al (0.61±0.13mg/l), Fe (0.21±0.06mg/l), Pb (ND), Cr (ND), and Mn (0.03±0.03mg/l). The overall average percentage compliance WHO limits were Al (70.60%, Fe (85%), Pb (100%), Cr (100%) & Mn (91%) respectively. The results revealed that all the selected HMs concentration in the public drinking water within the period were within the WHO recommended aluminum concentration that was slightly above the recommended limit of 0.20mg/l. The study recommended for limit except a substitute of aluminum sulphate in public water treatment and also concluded that the selected HMs concentrations in the public water supply in Abuja Metropolis within the period were in compliance with the WHO quality for safe drinking water and therefore safe for human consumption. However, concern was raised for its aluminum level and possible health implications on long-term exposure particularly the aged population.

New entry point of membrane technology for public water treatment plants in Malaysia

New entry point of membrane technology for public water treatment plants in Malaysia

Monitoring of iodine species during water purification at a public water treatment plant in Japan

Abstract Iodine is an essential element for humans; however, it can be toxic depending on its chemical form. A variety of toxic and non-toxic iodine species have been identified in environmental water and in the drinking water produced by public water treatment plants. Here, we examined the change of iodine species during the water treatment process at a public water treatment plant in Japan. Samples of raw water and of treated water immediately after each of eight treatment stages comprising the treatment process were collected, and a speciation analysis was conducted by means of ion chromatography– and size-exclusion chromatography–inductively coupled plasma mass spectrometry. In the raw water, iodine was found mainly as iodide or iodinated humic substances that were ultimately oxidized and transformed into iodate, a form non-toxic to humans, by two independent oxidation stages in the water treatment process – ozone treatment and chlorine treatment. No disinfection byproducts were detected at any stage of the treatment process. Fluorescence spectrometry with multivariate analysis revealed that humic substances were markedly decreased by ozone treatment, but not by chlorine treatment. The present results show that, at the plant-scale, ozone treatment is an effective means of removing toxic iodine species from raw water.

Inadequate water treatment quality as assessed by protozoa removal in Sarawak, Malaysia.

ABSTRACTProviding safe drinking-water to human civilization is indispensable; it is one of the most cost-effective means of reducing the disease burden of diarrhea. Unfortunately, water supply quality monitoring from public water treatment plants (WTPs) is often neglected or taken for granted. To determine the produced water quality, WTPs in Sarawak, Malaysia were assessed for their protozoa removal ability. A self-administered questionnaire based on the regulations in the Drinking-water Standards for New Zealand (DWSNZ) was developed. Optional 10-liter raw water samples were collected from willing WTPs for the detection of protozoan cysts. Routine physical and microbial testing of WTP parameters were also requested for raw water quality overview. Two of the nine assessed WTPs achieved three log credits in the treatment component, one of which belonged to Peninsular Malaysia. No log credits were obtained in the other tested components for any samples. Most of the WTPs employed “Coagulation, Sedimentation, and Filtration” using rapid gravity filters without enhancement (P < 0.05). Giardia cysts were detected in raw water sources used for treatment, and the geographical location was identified as an influencing factor for raw water quality. There is an urgent requirement for active collaboration and holistic approaches to review existing water management policies and interventions. WTPs in Sarawak did not achieve the log credits required to safeguard the microbial quality of the water supplied; however, only Giardia cysts were detected in 10-liter raw water samples despite routine microbial parameter monitoring showing disturbing contamination levels.

Risk factors of Helicobacter pylori infection in an urban community in Northeast Brazil and the relationship between the infection and gastric diseases.

Helicobacter pylori, a water contaminant, is the primary pathogenic agent associated with gastric diseases in humans. Exposure to H. pylori is more likely higher in developing countries. This study aimed to evaluate the risk factors associated with H. pylori infection in patients undergoing endoscopy to validate the cause of dyspeptic symptoms in an urban population in northeast Brazil and to compare the urease test and polymerase chain reaction assay results with the histopathological findings. We evaluated 200 of 759 individuals with dyspeptic complaints from Campina Grande, State of Paraiba, northeast Brazil. Patients underwent endoscopy, followed by gastric biopsies. Logistic regression analysis was performed to adjust for confounders and to determine significant risk factors of dyspeptic disorders. Women accounted for 72.5% (145/200) of the participants. Approximately 59.8% (120/200) of the samples tested positive for H. pylori based on histological examinations. The specificity of polymerase chain reaction assay was higher than that of the urease test (77% vs. 64%, p=0.034). City drinking water [odds ratio (OR): 2.6; 95% confidence interval (CI): 1.3-5.21; p=0.004] and smoking (OR: 4.0; 95% CI: 1.13-14.5; p=0.031) were the risk factors of H. pylori infection. Belching was the most common symptom associated with H. pylori infection (p=0.05). The increased risk of H. pylori infection associated with non-treated water consumption indicates the need for improvements in public water treatment and better sanitary conditions because these can be a source of not only H. pylori infections but also other water-borne pathogen infections.

Photodegradation of taste and odor compounds in water in the presence of immobilized TiO2-SiO2 photocatalysts

Disinfection by ultraviolet (UV) radiation is a growing trend in public water treatment systems because of its effectiveness with respect to inactivation of protozoa and other pathogenic microorganisms. However, removal of different classes of organic compounds, including taste and odor compounds in water is not effective with UV irradiation. In this study, a novel TiO2-based immobilized photocatalyst is developed to enhance the UV photodegradation of two of the major taste and odor compounds, 2-methylisoborneol (MIB) and Geosmin (GSM) in water. Evonik (formerly Degussa) P-25 powder-modified TiO2 was immobilized on glass slides using TiO2-SiO2 sol-gel mixture as the binder and calcined at 500 °C. Several catalyst films with different Si amounts were synthesized and characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IR), diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL) and scanning electron microscopy (SEM). Photocatalytic degradation of MIB and GSM was investigated by irradiating aqueous solutions under UV-A light (350 nm). Generation of hydroxyl radicals (OH) was also assessed to evaluate the activity of the photocatalyst films. Catalyst films with surface ratios of Ti:Si ≈6 showed similar degradations rates but better robustness compared to immobilized P25 films.

State and green crimes related to water pollution and ecological disorganization: water pollution from publicly owned treatment works (POTW) facilities across US states

Green criminologists often refer to water pollution as an example of a green crime, but have yet to produce much research on this subject. The current article addresses the need for green criminological analyses of water pollution problems, and draws attention to an overlooked issue: water pollution emissions from state owned public water treatment facilities or POTWs. Legally, POTWs may emit certain quantities and kinds of pollutants to waterways following treatment. This does not mean, however, that those emissions have no adverse ecological or public health impacts, or that those emissions cannot also be employed as examples of green crimes or green-state crimes. Indeed, from the perspective of environmental sociology and ecological Marxism, those emissions generate ecological disorganization. Moreover, POTW emissions contain numerous pollutants that generate different forms of ecological disorganization. The current study uses POTW emissions data drawn from the US EPA’s Discharge Monitoring Report system for 2014 to illustrate the extent of pollution emitted by POTWs in and across US states as one dimension of ecological disorganization. To contextualize the meaning of those data, we review US water pollution regulations, review the health and ecological impacts of chemicals emitted by POTWs, and situate those emissions within green criminological discussions of green crime and green-state crimes.

Impacts of extreme flooding on riverbank filtration water quality

Riverbank filtration schemes form a significant component of public water treatment processes on a global level. Understanding the resilience and water quality recovery of these systems following severe flooding is critical for effective water resources management under potential future climate change. This paper assesses the impact of floodplain inundation on the water quality of a shallow aquifer riverbank filtration system and how water quality recovers following an extreme (1 in 17year, duration >70days, 7day inundation) flood event. During the inundation event, riverbank filtrate water quality is dominated by rapid direct recharge and floodwater infiltration (high fraction of surface water, dissolved organic carbon (DOC) >140% baseline values, >1 log increase in micro-organic contaminants, microbial detects and turbidity, low specific electrical conductivity (SEC) <90% baseline, high dissolved oxygen (DO) >400% baseline). A rapid recovery is observed in water quality with most floodwater impacts only observed for 2–3weeks after the flooding event and a return to normal groundwater conditions within 6weeks (lower fraction of surface water, higher SEC, lower DOC, organic and microbial detects, DO). Recovery rates are constrained by the hydrogeological site setting, the abstraction regime and the water quality trends at site boundary conditions. In this case, increased abstraction rates and a high transmissivity aquifer facilitate rapid water quality recoveries, with longer term trends controlled by background river and groundwater qualities. Temporary reductions in abstraction rates appear to slow water quality recoveries. Flexible operating regimes such as the one implemented at this study site are likely to be required if shallow aquifer riverbank filtration systems are to be resilient to future inundation events. Development of a conceptual understanding of hydrochemical boundaries and site hydrogeology through monitoring is required to assess the suitability of a prospective riverbank filtration site.

Survey of two perfluorinated organic compounds (PFOA and PFHxA) in water and biota surrounding a polyfluorinated chemical plant

Perfluorooctanoic acid (PFOA) and perfluorohexanoic acid (PFHxA) concentrations were measured in water and biota samples collected within and near a polyfluorinated chemical plant in coastal Mississippi. Effluents from the site and from the local public water treatment plant were sampled along with municipal water supplies, shallow groundwater beneath the site, nearby surface waters, and local biota. Highest concentrations were from stormwater ([PFOA] = 85—530 ng/l; PFHxA = 140—590 ng/l) and shallow groundwaters ([PFOA] = 44—1000 ng/l; PFHxA = 210—3100 ng/l) collected at the site. The local public water treatment effluent also had relatively high PFHxA concentrations (310—590 ng/l). Intermediate PFOA concentrations were measured in effluent samples (21—33 ng/l) and irrigation water from a public works facility (15—48 ng/l). Drinking water and all surface waters had low PFOA and PFHxA concentrations (PFOA = 1.1—3.0 ng/l; PFHxA < 1.4 ng/l). Tissues from local fish and blue crab had undetectable PFOA and PFHxA concentrations. Results suggest that evaporation and subsequent percolation of contaminated stormwater into the shallow aquifer is the major pathway for perfluorinated contaminants to escape from this site.

Public Drinking Water Violations in Mountaintop Coal Mining Areas of West Virginia, USA

Mountaintop coal mining (MTM) has adverse impacts on surface and ground water quality. Instances of domestic well water contamination from mining activities have been documented, but possible mining impacts on public water treatment systems are unknown. We analyzed the US Environmental Protection Agency’s Safe Drinking Water Information System to examine the number and type of public water treatment violations in West Virginia for the years 2001–2009. Violations were compared between three groups of water treatment facilities: those in counties with mountaintop coal mining (n=161 facilities), coal mining other than mountaintop mining (n=184 facilities), and with no coal mining (n=137 facilities). Adjusting statistically for system size and water source, there were 73.0 violations per system in MTM areas, 16.7 violations per system in other mining areas, and 10.2 violations per system in non-mining areas (F=7.21, df=7,475, p<0.0001). Excess violations in MTM counties were most often related to failure to conduct required sampling for organic compounds. Complete sampling and reporting of public drinking water quality in MTM areas is needed.

From Flowback to Fracturing: Water Recycling Grows in the Marcellus Shale

In Pennsylvania, recycling water from wells in the Marcellus Shale has been transformed from a trend to an essential skill. The tipping point came in mid-April in a notice from the state’s Department of Environmental Protection (DEP) telling 15 public water treatment plants to stop handling waste water from wells in the Marcellus. The order to the only public facilities treating water from fracturing was voluntary, but the intent was clear. In the letter, Michael Krancer, the DEP secretary said: “Now is the time to take action to end this practice.” If there was any doubt, the US Environmental Protection Agency (EPA) followed up with a letter in May telling the state agency to make that a mandatory order. The federal agency said it would contact large oil and gas companies and the water treatment facilities to ensure they were no longer processing water that had flowed back after fracturing, and then disposing it in the state’s waterways. At that time two-thirds of the water from fracturing was recycled in Pennsylvania, where water use for shale gas companies has become a battleground with environmentalists, politicians, and the people who live on the land holding enormous natural gas reserves. The industry was already moving toward recycling, said Pete Miller, water resources manager of the Marcellus Shale division at Range Resources, which reuses nearly all the water from its wells there. “When the standard came out, it was another push in that direction.” The state’s letter sparked a rush by those who faced higher disposal costs because they could no longer have their waste water treated in state. “People are calling and telling me, ‘I’ve got to figure this out,’” said Dave Grottenthaler, general manager of Kroff Oil Services, a Pittsburgh water treatment specialist that got into fracturing water reuse early on. “I’ve been telling them for a while, you can reuse all your flowback and you will be safe.” Range Resources is evidence to how fast this transition can happen. It first used a mixture of fracturing flowback water and fresh water in August 2009. In 2010, it said it reused 96% of its produced water in Pennsylvania.

Is there an association between bacteriological drinking water quality and childhood diarrhoea in developing countries?

To investigate the association between bacteriological drinking water quality and incidence of diarrhoea, we conducted a 1-year prospective study in the southern Punjab, Pakistan. Diarrhoea episodes, drinking water sources and drinking water quality were monitored weekly among children younger than 5 years in 200 households. We found no association between the incidence of childhood diarrhoea and the number of Escherichia coli in the drinking water sources (the public domain). A possible trend was seen relating the number of E. coli in the household storage containers (the domestic domain) and diarrhoea incidence, but this did not reach statistical significance. Faecal contamination levels in household water containers were generally high even when the source water was of good quality. Under conditions such as this, it is questionable whether public water treatment will have a significant impact on the incidence of endemic childhood diarrhoea.

Changes in the incidence of gastroenteritis and the implementation of public water treatment

There are few data available on the incidence of endemic waterborne disease in the developed world. This study aims to determine if there was a measurable decline in gastroenteritis related faecal specimens following the introduction of water treatment. The rate of faecal specimens for gastroenteritis was obtained for 17 communities one year before and after the introduction of water treatment in two states of Australia between 1992 and 1996. Of these 17 systems, 10 had filtration added to existing disinfection, while seven had both disinfection and filtration or disinfection alone added to no existing treatment. The rate of faecal sampling varied from a reduction of 55% to an increase of 198%. Large changes in water quality parameters occurred following treatment but there was no significant correlation between these changes and changes in the rate of faecal specimens. In this study there was no consistent change in gastrointestinal related faecal specimens despite marked changes in water quality. This suggests that the reduction in endemic gastrointestinal disease as a result of the introduction of water treatment was small as a percentage of all gastroenteritis. However, water treatment remains essential to protecting public health.

Unsuccessful bidder cannot challenge award of contract

An unsuccessful bidder cannot challenge the propriety of the award of a contract by a water district for a public water treatment project, according to a Colorado appellate court.