News Items Archive 2018
Please note that, for some of the older entries, links may no longer be functional.
A new cost effective, long life and low resistance filter cartridge for water treatment
Multifunctional nanocoagulant for single-step removal of water contaminants
A team of workers has developed a multifunctional coagulant (AMC)
capable of removing a broad spectrum of contaminants while maintaining a high stability. AMC not only removes particulate matter but also dissolved contaminants such as nitrate. It also achieved removal efficiencies of over 90% for all tested micropollutants, despite the variability in contaminant charge and hydrophobicity, while conventional coagulants only removed between 0 and 60%.
The Impact of Burst-Driven Mains Renewals on Network Leakage Performance
UKWIR has released a useful report showing that a burst-driven renewal programme
can achieve a reduction in burst frequencies leading to a reduction in the natural rate of rise (NRR) of leakage. This results in a reduction in the optimal survey frequencies, in turn reducing the costs of active leakage control (ALC) to maintain leakage at the current level.
Is the global public willing to drink recycled water?
An Australian Group has reviewed 150 papers
on the subject of public acceptability of potable re-use of treated wastewater.(PRW) Population growth and climate change mean that many cities across the world will inevitably require either desalination and/or PRW. Coastal cities with projected water shortages generally have the option of either PRW or desalination, whereas inland cities in many cases will eventually be left with no option other than PRW. The paper give useful guidance for practitioners considering PRW. What is still missing from public acceptance literature and campaigns is the message that wastewater effluent has been mixed into many water supplies globally for a very long time.
Improved method for removing mercury from water
A potential alternative to membrane filters
A recent paper provides a research update
on the biologically inspired liquid-enabled gating mechanism that acts as a novel filtration and separation approach offering reduction in transmembrane pressure (TMP), improved throughput, and reduced fouling. It studies the performance of such Liquid Gated Membranes (LGMs) and presents their benefits for filtration in the presence of model inorganic (nanoclay particles) fouling. It shows over twofold higher throughput, nearly threefold longer time to foul, more than 60% reduction in irreversible fouling, ability to return to baseline pressures after backwashing along with reduction in use of backwash water, and 10%-15% reduction in TMP for filtration of nanoclay particles.
EC proposals for amendment of the Drinking Water Directive.
Proposals to update the EC Drinking Water Directive
are proceeding steadily through the labyrinthine proceduresand the most recent text adopted by the European Parliament on 23 October 2018 includes the following:-
“Drinking water quality parameters: legislation shall introduce new chemical parameters or groups of parameters, to tighten the maximum limits for certain pollutants such as lead (to be reduced by half), per- and polyfluoroalkyl substances (PFAS), harmful bacteria, and introduce new caps for endocrine disruptors Bisphenol A and Beta-estradiol (50-28-2). It also monitors levels of microplastics, an emerging concern.
Surveillance: with regard to the regular monitoring, Member States shall ensure access to installations in priority premises for the purposes of sampling and may set up a monitoring strategy, in particular as regards Legionella pneumophila, which are responsible for the majority of cases of legionnaire's disease in the Union.”
Prevention of UF membrane fouling in drinking water treatment
A recent paper by workers at Imperial College, London shows that for a membrane ultrafiltration treatment
in a bench scale study, intermittent addition of H2
into the membrane tank during backwash events (after coagulation pre-treatment) successfully prevented the development of any significant membrane fouling.
Improving performance of GAC filters for drinking water treatment.
US workers have shown that addition of oxidants (e.g., 0.6mg Cl2
/L HOCl) could decrease terminal head loss by 20% in dual media filters and 40% in multimedia filters. These hydraulic benefits
were achieved without significantly affecting removal of assimilable organic carbon (AOC), total organic carbon (TOC), turbidity, or particle counts.
Legionella in biofilms
A PCR study comparing biofilms in a chloraminated water system
in the US with a Swedish system with no residual showed the presence of Legionella in 10 of 23 samples from the un-chloraminated system but in none of 35 samples from the chloraminated system.
Photocatalytic BPA removal using microbeads
By anchoring food-grade cyclodextrin onto TiO2
microbeads between 3 and 5 μm, workers in Texas were able to remove over 99% of various contaminants
with dissimilar hydrophobicity (i.e., bisphenol A, bisphenol S, 2-naphthol, and 2,4-dichlorophenol) within 2 h under a low-intensity UVA input (3.64 × 10–6
einstein/L/s). The beads were readily removable and could be recharged with cyclodextrin and reused.
Lead and cardiovascular disease
A large US research study has suggested that increased risks of premature death from cardiovascular disease may be associated with relatively low blood lead levels that have not previously been considered harmful. The study and its conclusions
have been challenged
Future actions on per- and polyfluoroalkyl substances (PFAs)
Following a meeting of over 50 scientists and regulators in November 2017 a statement has been published
which identifies both the respective needs of and common goals shared by the scientific and the policy communities, makes recommendations for cooperative actions, and outlines how the science–policy interface regarding PFASs can be strengthened using new approaches for assessing and managing highly persistent chemicals such as PFASs. Short chain PFASs have generally been overlooked but they may be contaminants of emerging global concern due to their high persistence and environmental mobility, modes of action similar to those of long-chain PFASs, wide presence in products, and poor removability from drinking water
and contaminated sites. Hence, a growing number of scientists, regulators, and civil society organizations are increasingly calling for effective and efficient assessment and management of overlooked PFASs. Future regulation in drinking water is a possiblility.
Measuring lead in water using smart phones
Researchers at the University of Houston have created an inexpensive system using a smartphone and a lens made with an inkjet printer that can detect lead in tap water at levels commonly accepted as dangerous. The researchers built a self-contained smartphone microscope that can operate in both fluorescence and dark-field imaging modes and paired it with an inexpensive Lumina 640 smartphone with an 8-megapixel camera. They spiked tap water with varying amounts of lead, ranging from 1.37 parts per billion to 175 parts per billion. They then added chromate ions, which react with the lead to form lead chromate nanoparticles; the nanoparticles can be detected by combining colorimetric analysis and microscopy. They say that this technique has the potential to enable individual citizens to examine Pb2+
content in drinking water on-demand in virtually any environmental setting.See Details 1
and Details 2
Simultaneous measurement of a range of DBPs
Workers in Sweden investigated and developed a method for simultaneous measurement of 20 DBPs
from five different structural classes (both regulated and non-regulated). The method was further developed for 11 DBPs using solid-phase extraction and gas chromatography coupled with a halogen-specific detector (XSD). The XSD was highly selective towards halogenated DBPs, providing chromatograms with little noise. The method allowed detection down to 0.05 μgL−1 and showed promising results for the simultaneous determination of a range of neutral DBP classes. However, haloacetic acids (HAAs) should be analyzed separately as some HAA methyl esters may degrade giving false positives of trihalomethanes (THMs).
Removal of heavy metals from water in the field
Australian workers have demonstrated
that if solid aluminium is immersed in liquid gallium at room temperature layers of aluminium oxide will be formed on the surface of the gallium. These nano-sheets are highly porous and suitable for filtering both heavy metal ions and oil contamination at unprecedented, ultra-fast rates. The authors say that "You just add aluminium to the gallium and out comes aluminium oxide when its surface is exposed to water. You can use gallium again and again. Gallium never participates in the reaction"
USEPA has established threshold limits on some DBPs
, which are known as regulated DBPs (R-DBPs). The human health risks associated with R-DBPs in drinking water distribution systems and application of stricter regulations have led water utilities to switch to alternative disinfectants. However, the use of alternative disinfectants causes formation of a new suit of DBPs known as unregulated DBPs (UR-DBPs), which in many cases can be more toxic. Canadian workers have carried out a review of UR-DBPs and prioritised their importance. Haloacetonitriles and haloacetaldehydes are identified as important UR-DBP groups while dichloroacetonitrile and trichloroacetaldehyde are identified as critical UR-DBPs species.
Emergency water treatment system
USEPA in collaboration with WaterStep has developed a modular, mobile water treatment system
known as the Water on Wheel - Emergency Mobile Drinking Water Treatment System, or the WOW cart. 78 Mini versions of the WOW cart were deployed after the recent Puerto Rico hurricane. Each Mini included everything needed for quick assembly and operation and could deliver safe drinking water within 30 minutes of set-up. Each of these Minis has a solar panel and a chlorine generator, and can provide up to 10,000 gallons of drinking water each day.
Resilience in water supplies.
Defra, the Environment Agency, the Drinking Water Inspectorate and Ofwat have issued a joint letter to water companies in England
outlining what is required to build resilience in water supplies. The letter sets out whaat companies need to do, and what steps the letter writers will be taking to help them ensure that customers’water needs are met in a safe, resilient and efficient way, while protecting the environment and respecting good supply practice and the needs of other water users.
DWI information letter on monitoring variations
DWI has issued an information letter
providing companies with instructions for applying for monitoring variations under regulation 9(6)(b) and updated reporting requirements for regulation 28 (4) of the Regulations.
Lead in tap water after lead pipe replacement
USEPA has issued a note regarding lead in tap water
after a programme of lead pipe replacement in Madison, Wisconsin. . High levels of lead were being found in first draw samples where pipes had been replaced up to 4 years previously. Research showed that particulate lead had been accumulated in iron and manganese scale and was capable of being relesed over long periods after lead pipe replacement.
Informing public attitudes to non-potable water reuse
A recent study evaluated how different ways of framing messages about the safety of recycled water might impact on public attitudes
. The researchers used four different animated videos emphasising different aspects of the issues surrounding non-potable reuse of reclaimed water. Water safety communications framed in terms of compliance with water quality requirements imporoved public perceptions whereas safety message framed in terms of the selection of water treatment technology to remove contaminants or in terms of non-potable water risks relative to other every-day risks were not successful. This study would be a useful guide for any future plans to re-use treated wastewater as a drinking water source.
Evaluating chemicals as endocrine disruptors
EPA scientists recently published an article about their analysis of a high-throughput screening assay
which detects chemical effects on steroidogenesis., a key aspect of endocrine disruption.
The new assay, called the high-throughput H295R assay (HT-H295R), can quickly and efficiently screen hundreds to thousands of chemicals and has the potential to become an alternative to or even replace the existing steroidogenesis assay.
Water from the air
A team at University of Akron in Ohio, US is developing nanofibres
with which water harvesters could yield up to 180 litres of water per square metre every day. In comparison, a commercial system currently in use in Morocco only produces around 30 litres per square metre per day.
The team envisions using a small battery to cool an element attached to the material which would mean the harvester could operate beyond the range of typical fog nets – even in deserts. The device has not yet been developed.
Indicator bacteria in non- warm-blooded animals
A recent study showed
that standard faecal indicator bacteria, ( E.coli
, enterococci and Cl.perfringens
) can also occur in high concentrations in poikilothermic animals (i.e., animals with body temperatures that vary with the ambient environmental temperature, such as fish, frogs, and snails) in an alluvial backwater area in a temperate region, indicating that a reconsideration of this long-standing indicator paradigm is needed. This study suggests that poikilotherms must be considered to be potential primary sources of SFIB in future studies.
Climate change and cyanobacterial blooms.
Global review of drinking water regulations and standards
WHO has published a global review
summarising information from 104 countries and territories on values specified in national drinking-water quality standards for aesthetic, chemical, microbiological and radiological parameters.
Nitrate and colon cancer
A recent Danish epidemiological study
concludes that drinking water concentrations of nitrate below the current 50mg/l standard can be shown to carry an increased colon cancer risk.(The authors note that they had no individual data on smoking, diet, alcohol intake or physical activity, but state that educational achievement is an appropriate proxy for these factors in the Danish population.)
Impact of high velocity flushing on lead in tap water
US Water Research Foundation Report “Evaluation of Flushing to Reduce Lead Levels (project#4584)
” concludes that high velocity flushing after full or partial lead plumbing replacement is beneficial on lead levels in tap water although benefits may not be seen immediately. However it is not recommended in houses where the water system has not been disturbed.
Microbial source tracking for determining sources of pollution.
Faecal indicator bacteria (FIB) provide no information about actual sources of pollution but microbial source tracking can do so. In studying a Florida watershed, workers monitored faecal coliforms
, enterococci, a marker gene for avian faeces (GFD), and a marker gene for human-associated Bacteroides (HF183) in sediment, vegetation, and water samples collected monthly from six sites over two years. This demonstrated that birds, not sewage, were the main source of FIB.
DWI Annual Reports for 2017
DWI has published its Annual Reports on Drinking Water in England
which show that supplies remain of exceptionally high quality although private supplies, while continuing to improve, still had a 5.5% tests in England and 4.7% in Wales not meeting the required standards.
Novel approach to water billing in times of shortage
An innovative system for pricing household water
is proposed in a new EU-funded study researched in the US and UK. The tariff is designed by combining the economic value of water with reservoir storage data, and is intended to cut water usage during times of shortage by charging large-volume
consumers a higher rate which increases as water becomes scarcer. The tariff increase subsidises water for other users, whilst also ensuring the system is economically stable. A case study suggests that the tariff could cut water consumption in the city of Valencia by up to 18%.
Removal of mercury by magnetised carbon nanotubes
WHO Guidance on Developing Drinking Water Regulations and Standards.
WHO has published the above Guidance
intended for those agencies in countries with limited resources that are responsible for developing, implementing and enforcing national or subnational drinking-water quality regulations and standards.
Management of Radioactivity in Drinking Water
WHO has published an exceptionally comprehensive report on Radioactivity in water
in the form of 4 sections presented as questions and answers. The sections cover non-emergency situations; emergency situations; supporting information relevant to both types of situation; and a number of case studies.
Upgrading small water systems to reduce disinfection by-products.
Technical Auditing of Water Supply Systems
Czech Republic workers have published two papers on Technical Auditing of Water Supply Systems. The first paper
describes how to perform a rapid and efficient preliminary identification of problematic areas and elements of the entire water supply system. It presents a methodology and Technical and Energy Audit, as well as an effective preliminary assessment of the technical condition of water supply systems. It presents the structure of proposed technical indicators, the method of their determination and evaluation, as well as including a presentation of case studies.
The second paper
presents a comprehensive method for assessing the technical condition of water treatment plants as part of a set of procedures for assessing the entire water supply system'
Are we running out of water?
The Guardian newspaper has published a very thought-provoking briefing which provides a reasoned exposition on why shortage of water
is becoming a serious issue and likely to become worse. It also looks at steps that could be taken to make better use of water and ameliorate the developing situation.
DWI review of freeze - thaw event March 2018.
DWI has reported on the Companies' actions in handling the widespread freeze/thaw event in March 2018
. It concludes that a number of companies failed to submit their final report by the date requested, and it was necessary for the Inspectorate to request a considerable amount of further data and information from most companies which was missing from the final reports. However, some companies were unable to identify root causes of inability to maintain supplies and the Inspectorate considers this response to be inadequate, and an unsustainable position for those individual companies. The procurement of sufficient emergency supplies of drinking water was clearly a challenge for some companies, and had the severe weather lasted for longer than it did, the abilities of some companies to provide sufficient alternative supplies to consumers could have been severely compromised. The report imcludes a number of recommendations.
Network and Information Systems (NIS) Regulations 2018.
Benefits of drinking water Fluoridation
A recent US study
confirms a substantial caries-preventive benefit of fluoridated water supplies for U.S. children and that the benefit is most pronounced in primary teeth.
Induction of Escherichia coli into a Viable but Non Culturable (VBNC) state through chlorination/chloramination
Workers in China have shown
can become VBNC after treatment with chlorine and chloramine. At concentrations of 1, 2, 3, and 4 mg/L, the counts of culturable E. coli
cells decreased from 106
CFU/mL to 0 CFU/mL at 5–60 min post treatment. Meanwhile, viable cell counts were still approximately 103
cells/mL TheVBNC cells are capable of resuscitation given the right conditions. ( if the same can be shown to be true for bacterial pathogens this could be significant
Warning of future water deficits.
A recent Environment Agency report
suggest that if no action is taken to reduce demand and increase supply of water, most areas will not meet demand by the 2050s under high greenhouse gas emissions and high population growth scenarios .Even low population growth and modest climate change scenarios suggest significant water supply deficits by the 2050s, particularly in the south-east. ( where Government plans major future growth
) Substantial volumes of water are lost during treatment and in people's homes. In total, one-third of water taken from the natural environment is wasted either through leaky pipes, losses in treatment or in the home
Lead in tap water in schools and large buildings.
A total of 130 outlets (fountains, bathroom and kitchen taps
) were sampled for dissolved and particulate lead as well as copper. Sampling was conducted at 8 schools and 3 institutional (non-residential) buildings served by municipal water of varying corrosivity, with and without corrosion control (CC), and without a lead service line. In first draw samples after overnigh stagnation higher concentrations were observed in schools with corrosive water without CC (0.9–201 μg Pb/L, median: 14.3 μg Pb/L), Lead concentrations were <10 μg Pb/L in all samples following 5 min of flushing. However, after only 30 min of stagnation, first draw concentrations increased back to >45% of values in 1st draw samples collected after overnight stagnation. Concentrations of particulate Pb varied widely (≥0.02–846 μg Pb/L) and Pb levels across outlets within the same building varied widely (up to 1000X) especially in corrosive water (0.85–851 μg Pb/L after 30MS) confirming the need to sample at each outlet to identify high risk taps.
Based on the much higher concentrations observed in first draw samples, even after a short stagnation, the first 250mL should be discarded unless no sources of lead are present .Results question the cost-benefit of daily or weekly flushing as a remediation strategy.
Identification of microplastics using Raman spectroscopy.
A review of microplastic pollution
considers that Raman spectroscopy is the method of choice for identifying microplastics ( < 20 μm ). It discusses drawbacks and solutions to overcome them as well as non-conventional techniques which might permit real-time monitoring. (There is currently great interest in microplastics and studies have shown bottled waters to have higher levels than tap water. There is at present no evidence that microplastics in drinking water present any health risk
Application of a salivary immunoassay in a prospective community study of waterborne infections
A study was carried out in a city in Massachusetts
which used a microbiologically contaminated river as its water source, during summer-early winter periods before and after construction of a new drinking water treatment plant. The study used salivary antibody immunoassay and demonstrated significant associations between gastrointestinal symptoms and Cryptosporidium
and norovirus infections, and between water-related exposures and Cryptosporidium
infections. Among individuals who used home water filters, associations between non-boiled tap water consumption and Cryptosporidium
immunoconversion were not significant before and after new plant construction.
Treated wastewater for aquifer recharge
Flow cytometric investigation of Slow Sand Filter function.
Swedish workers studied flow cytometric profiles of new and old established slow sand filters before and after scraping
. The performance of an established SSF was stable: total organic carbon (TOC), pH, numbers of heterotrophs, coliforms, E. coli
, and FCM bacterial profile were unaffected by scraping. However, the performance of two newly-built SSFs containing new and mixed sand was compromised. This suggests that the impact of the surface biofilm on effluent water is greater when the deep sand bed biofilm is not established.
Impact of UVA pre-radiation on UVC disinfection performance.
The disinfection performance of a novel sequential process, UVA365nm LED followed by UVC265nm LED (UVA-UVC)
, was evaluated. The results revealed that the responses of different E coli
strains to UVA-UVC varied. While inactivation of 3 strains was increaased by UVA a fourth strain became less inactivated. The study discusses the biochemical mechanisms at play and postulates reasons for the different results. (It also emphasises the danger of extrapolating experimental results from one strain of an organism to the species in general
Cyanobacteria link to Alzheimer's disease hypothesis not supported.
Fluoridation recommended in Australia.
The Australian National Health and Medical Research Council having reviewed all recent data concludes
that drinking water fluoridation has positive health benefits and the numerous claims of associations between fluoridation of water and a range of health problems are unsupported. Levels of dental fluorosis are not higher in areas with fluoridated water.
Drinking Water associated disease outbreaks in USA 2013-4
42 outbreaks were reported leading to 1006 cases
and 13 deaths. 57% of outbreaks and all deaths were due to Legionella
, Eight outbreaks caused by two parasites resulted in 289 (29%) cases, among which 279 (97%) were caused by Cryptosporidium
, and 10 (3%) were caused by Giardia duodenalis
. Chemicals or toxins were implicated in four outbreaks involving 499 cases, with 13 hospitalizations, including the first reported outbreaks (two outbreaks) associated with algal toxins in drinking water. The largest reported outbreak was of 369 cases of acute gastrointestinal infectio and 13 hospitalisations associated with contamination of a community/municipality water supply with the chemical 4-methylcyclo-hexanemethanol (MCHM). The contamination was caused by failure of a chemical storage tank in a facility located next to a river, only a short distance upstream of a drinking water intake.
Association Between Perceptions of Public Drinking Water Quality and Actual Drinking Water Quality.
A study in Newfoundland involving 100 householdsin each of 45 communities
concluded that the majority of the respondents (>56%) were either completely satisfied or very satisfied with the quality of drinking water. Older, higher educated and high-income group respondents were more satisfied with water quality than the younger, less educated and low-income group respondents. The study showed that there was no association with public satisfaction level and actual water quality of the respective communities.
Economic Assessment of Waterborne Outbreak of Cryptosporidiosis
An outbreak of cryptosporidiosis in Western Ireland in 2007
has been estimated as costing over €19 million. Because of the difficulty in installing additional treatment advice to consumers to boil water was in place for 158 days.
A recent paper describes how UV and hydrogen peroxide can react with phenolic compounds in water
to form toxic enedials and oxoenals. In addition to raising concerns about potential health risks of oxidative water treatment,the authors suggest the potential for formation of these toxic compounds in sunlit surface waters, atmospheric water, and living cells.
Mainstreaming Potable Water Reuse in the United States
The USEPA in collaboration with others has published a very detailed and informative report
on a workshop held in 2107which considered the institutional hurdles to potable reuse. Despite the many successful schemes in operation in the US and worldwide there is still resistance to such schemes.
Global overview of national regulations and standards for drinking-water quality
WHO has published a fascinating review of regulations and standards for drinking water quality
in 104 countries and territories, representing c 89% of the world's population, and their comparison with WHO Guidelines on Drinking Water Quality or WHO Health-based Values. The review shows a wide range of values and parameters being regulated for the different countries and frequent instances of values set higher than WHO guidance. For microbiological parameters only 1 country has not set a value for E.coli
while at the other extreme only single countries have set limits for one or more of amoeba, Vibrio cholera
, free living organisms, helminths, Legionella
, nematodes, parasites and plankton. Several countries have set values for parameters such as total heterotrophic bacteria, hardness or potassium for which WHO has considered it is not appropriate to set a value, while lead is one of only three parameters for which all 104 countries have set a value.
Radiation for removing organic contaminants
A recent review paper
presents radiation processing as a promising approach for removing organic contaminants, providing strong evidence of its efficacy, efficiency, safety, and feasibility. Focusing particularly on the use of electron-beam (EB) processing for the removal of organic pollutants from waste water and drinking water, the researchers present a compelling picture, relevant to stakeholders involved in water treatment and management. In recent years, EB accelerator technology has developed significantly, and its lower running costs and increased ease of operation make it a practical choice for water treatment applications. EB irradiation offers several advantages over other water treatment technologies: no chemical additives are required, no by-products are created, no lengthy exposure times are necessary and workers are not required to handle any highly reactive liquids or gases.
On-site non-potable water systems.
A recent report, “Making the Utility Case for On-site Non-potable Water Systems”
, catalogues the benefits, lessons learned, and key strategies for implementation of on-site non-potable water systems. The report includes interesting case studies. The report claims that these systems can save 25% of potable water use in domestic premises and 75% in commercial buildings.
NDMA formation in chloramination.
N-nitrosodimethylamine (NDMA), a probable human carcinogen disinfection by-product, has been detected in chloraminated drinking water
systems. Laboratory tests using 5 different potential NDMA precursors showed NDMA formation was faster and higher as dichloramine concentration increased.
DBPs and health impact on pregnancy outcomes.
Epidemiological studies have found that maternal exposure to disinfection by-products (DBPs)
may lead to adverse pregnancy outcomes although the findings tend to be inconsistent. A meta-analysis
of 32 studies found 12 of these reported a statistical association between maternal exposure to DBPs and adverse pregnancy outcomes. A maternal exposure to trihalomethanes (THMs) shows an increased risk of small for gestational age (SGA) and slightly increased risk of pregnancy loss. The review not unsurprisingly concludes more research is needed.
Lead in drinking water in schools and large buildings
A Canadian study
found first draw lead levels in schools with corrosive water without corrosion control (CC) of 0.9–201 μg Pb/L, (median: 14.3 μg Pb/L) while levels in schools with CC ranged from 0.2 to 45.1 μg Pb/L (median: 2.1 μg Pb/L). Partial flushing (30 s) and full flushing (5 min) reduced concentrations by 88% and 92% respectively for corrosive waters without CC. Lead concentrations were <10 μg Pb/L in all samples following 5 min of flushing. However after only 30 min of stagnation, first draw concentrations increased back to >45% of values in 1st draw samples collected after overnight stagnation. Results question the cost-benefit of daily or weekly flushing as a remediation strategy. As such, current regulatory requirements may fail to protect children as they may not identify problematic taps and effective mitigation measures.
PAC dosing for taste and odour removal.
WHO review of alternative disinfectants.
WHO has published a series reviewing
the state of the knowledge on the application, efficacy and toxicity of bromine, iodine and silver as drinking-water disinfectants.
Evaluation of corrosion indices
A recent paper evaluated the relevance of 10 known corrosion indices
according to their estimate of corrosion rate and iron particle release for 20 different water qualities. None of the indices properly predicted the level of risk associated with each water and corrosion and particle release were not correlated. Two novel indices were developed to predict the corrosion and particle release risks independently of each other.
Human infectious Cryptosporidium risk in drinking water supply catchments
An Australian paper reports on analysis of 962 samples
, taken during rainfall run-off conditions from 9 water supply reservoir locations, for Cryptosporidium
oocysts. 23 Cryptosporidium
species were detected, the most common being C. parvum
which was found in 23% of samples. Average infectivity of isolates was 18% with a maximum of 65.4%. The authors suggest that inclusion of measured infectivity and human pathogenicity data into a quantitative microbial risk assessment (QMRA) could reduce the source water treatment requirements by up to 2.67 log removal values.
Water fluoridation found safe and effective
Public Health England has published a report
comparing data on the health of people living in areas of England with differing concentrations of fluoride in their drinking water supply. The report concludes that water fluoridation is an effective and safe public health measure to reduce the frequency and severity of dental decay, and narrow differences in dental health between more and less deprived children and young people. It says that there is no convincing evidence of higher rates of hip fracture, Down’s syndrome, kidney stones, bladder cancer, or osteosarcoma (a cancer of the bone) due to fluoridation schemes. Although Dental fluorosis, at a level that may affect the appearance of teeth, was observed in 10% of children/young people examined in 2 fluoridated cities , there was no difference between children and young people surveyed in fluoridated and non-fluoridated cities when asked about their opinion on the appearance of their teeth.
Plastic particles in bottled water
There has been considerable media interest in the findings of a non-peer reviewed paper
, issued only as a press release and not in a recognised journal, which found traces of plastic particles in 93% of 259 bottles of packaged drinking water. The average count of plastic particles was 335/litre.
Recycled water scores best in taste test.
In a study in water stressed California
water preferences of 143 participants for one name-brand bottled water, one groundwater-sourced tap water, and one indirect potable reuse (IDR) water were assessed. (The IDR water is derived from groundwater into which reverse osmosis treated wastewater has been introduced). In blind tastings with 143 participants, the more nervous, anxious people in the study expressed the preference for IDR and bottled water, and were more negative about the more mineral-rich tap water. People more open to new experiences liked the three samples about the same
Heavy metal removal from water
A recent paper describes the development of a cheap, water stable metal–organic framework/polymer composite
, Fe-BTC/PDA, that exhibits rapid, selective removal of large quantities of heavy metals, such as Pb2+
, from real world water samples The material is further shown to be resistant to fouling when tested in high concentrations of common organic interferents, like humic acid, and is fully regenerable over many cycles. The authors suggest that this new material could become highly influential for in-home or wastewater treatment technologies, particularly in the event of an impending water crisis.
Detection of cyber attacks in water systems
Water systems are increasingly dependent on computerised systems and are therefore vulnerable to cyber attack. A competition (batadal
) was organised to compare the performance of algorithms for the detection of cyber attacks in water distribution systems. Details of the winning algorithm have been published.
Detection and prevalence of human enteric viruses in water
Anyone interested in water virology should not miss a recent Open Access paper
which comprehensively summarises recent progress on research regarding waterborne human enteric viruses. It reviews methods for concentrating and detecting viruses in water and compiles existing data on abundance and genetic diversity of viruses in water. It also discusses the use and importance of process controls in evaluating the efficiency of virus recovery and level of inhibition during the detection process.
Double disinfection, and UV-LEDs for drinking water treatment
A new study shows that a combined disinfection treatment with chlorine and UV radiation
can be highly effective in water disinfection. Chlorination followedby UV was more effective against a range of bacteriophages than either treatment alone. The same study reports that UV LEDs were effective against the same bacteriophages.
Fast-acting antidote in sight for cholera epidemics
Online fluorescence spectroscopy for the real-time evaluation of the microbial quality of drinking water.
A consortium of workers from UK water companies and academics carried out a study
which concluded that fluorescent dissolved organic matter (DOM) is strongly correlated with E. coli
and total bacterial cell counts. It is also superior to turbidity as an indicator of microbial water quality. They conclud3e that despite some limitations online fluorescent DOM sensors are a better indicator of the microbial quality of untreated drinking water than turbidity.
Direct pathogen detection in contaminated surface water
Workers in the USA studied a watershed
in which fecal coliforms have improved substantially in the watershed since its listing as a 303(d) impaired stream in 2002 and are now near United States recreational water criterion standards. Using molecular techniques they were able to detect
viruses (bocavirus, hepatitis E and A viruses, norovirus, and enterovirus G), bacteria (Campylobacter
spp., enterohemorrhagic and enterotoxigenic Escherichia coli
, uropathogenic E. coli
, Enterococcus faecalis
spp., and Vibrio
spp.), and eukaryotes (Acanthamoeba
spp., Entamoeba histolytica
, and Naegleria fowleri
. Comparison of the stream microbial ecology with that of sewage, cattle, and swine fecal samples revealed that human sources of fecal contamination dominate in the watershed.
Simple arsenic sensor
A hand-held sensor to measure arsenic levels in water
has been developed by researchers at University College London (UCL) and Imperial College London, with funding from BBSRC. The sensor uses a modified arsenite oxidase enzyme from E.coli. The small, sensitive and accurate sensor produces an immediate measure of the arsenic level in water, at a cost of less than $1 per test. This makes it suitable for testing multiple sites in rural areas in low and middle income countries, where the problem of arsenic poisoning from contaminated drinking water is greatest, and potentially saving lives. (patent application
Efficiency programmes best strategy for water security
Combatting water shortage such as is affecting Capetown in South Africa by capital works takes a long time and cannot solve immediate crises. A recent article in Source magazine
argues that water efficiency measures can prove a more immediate solution. On the basis of cubic metres gained, water efficiency programme investments are much cleaner, cheaper, faster and fairer than building new supplies. Australia learned this lesson during its 10-year Millennium Drought. Building new dams would have cost US$1,370 per Megaliter (/Ml) of water delivered. By contrast, the same Ml could be added by plugging leaks in the network at a cost of only US$365/ Ml and the country gained additional supplies by replacing high flow plumbing fixtures for just US$454/ Ml, less than a third of the cost of developing new supply.
ATP for rapid water quality assessment
While FWR does not endorse commercial products, readers may be interested in a new test
which can indicate the microbial content of a clean water in 3 minutes. Water is filtered then any retained microbial cells are lysed and the ATP released is estimated using the luciferin/luciferase procedure. The same company offers a kit for determining coliforms and E.coli within 24 hours.
Legionella outbreak attributed to change in water supply source
A report on the Legionnaires disease out break in Flint, Michigan
attributes the outbreak to change of water supply source to the Flint River and consequent reduction in chlorine levels. The majority of the Legionalla
isolated from premises ( 16 of 18) were serogroup 6, which is not detected by the widely used urine test for legionella
Solar powered desalination
Researchers in Spain have developed a stand-alone system for desalinating and treating water through electrodialysis
. The system is directly powered by solar energy and can be applied in off-grid areas. The research group already has a pilot and demonstration plant able to generate a cubic metre of drinking water every day.
Importance of dechlorination of drinking water samples for bacteriological analysis
Results have been published of a simple laboratory and field test study which confirm the importance of sodium thiosulphate dechlorination
of bacteriological samples. All samples held without sodium thiosulfate had lower bacteria counts than comparable dechlorinated samples. In addition chlorinated water supply samples held without sodium thiosulfate had an 87.5% false negative rate.
Yorkshire Water to plant 1 million trees
Yorkshire Water has announced plans to plant 1 million trees
as part of the creation of the Northern Forest . T he Company says that planting trees in the right place will help to slow the flow of water during potential flood events, mitigate carbon emissions and boost wildlife. Although not claimed, the trees could have a beneficial effect on water quality particularly in upland reservoirs.
Novel toxicity biosensor
Workers at the University of Bath are developing a novel microbial fuel cell
capable of responding to toxicants in water. The device is fabricated by screen-printing carbon-based electrodes onto a single sheet of paper. It is membrane-less, as the paper substrate itself acts as the separator between the two electrodes. The device is fully biodegradable. The device has been evaluated using formaldehyde as the toxicant but it is expected to respond to a range of other toxicants.
Direct potable re-use
A recent review
(paper)describes long-term experience of direct potable reuse (DPR) in Windhoek, South Africa (48 years) which shows that treated domestic sewage can be safely and cost-efficiently utilized for potable reclamation (0.72 €/m3). A multiple barrier strategy is employed in order to attain the highest possible safety levels. Although most potable reuse schemes are indirect (IPR) and involve groundwater recharge or reservoir augmentation, the discharge of treated wastewater ro rivers subsequently abstracted for potable treatment has been a longstanding practice. A few other DPR schemes are in existence but invariably involve feeding the treated wastewater to conventional treatment works. DPR is likely to increase as populations increase and WHO has issued guidance for future schemes. (WHO Guidance
Priming of rapid sand filters to enhance nitrification
Danish workers have shown that nitrifying communities in new rapid sand filters could be enriched
by microbiomes from well-functioning rapid sand filters in waterworks and that the enriched nitrifying consortium could be used to inoculate fresh filters, significantly shortening the time taken for the nitrification process to start.
Low Energy Desalination
A recent letter in Environmental Science and Technology Letters
describes a novel desalination process for brackish water which has lower energy requirements than conventional techniques. The procedure does not require any regeneration stage but is not suitable for seawater higher salt sourcers such as seawater.
Impact of changing source of water supply – United Utilities, Copeland
DWI has published its assessment of an incident in Cumbria in June 2017 in which large numbers of consumers were concerned by noticeable changes in their drinking water supplies. The area affected was supplied with soft surface-derived water from Ennerdale but in 2009 its licence to abstract was reduced and it became necessary to obtain additional supply. Four boreholes were licenced to provide the additional supplies although these provided much harder water. Commissioning trials of these boreholes were commenced in May 2017. wherupon many consumers began complaining. Although supplies remained safe the Company was remiss in not informing consumers of the changing supply which resulted in widespread concern. The supply was deemed unwholesome as it breached the Taste and Odour requirements of the Regulations. DWI made several recommendations but concluded that enforcement wqs not required at this time.