Lower chlorine residuals can be beneficial.
A study in the University of Sheffield using a laboratory based full scale DWDS experimental system with HDPE pipework showed that slightly reducing the amount of disinfectant residuals
used to maintain clean drinking water could deliver significant improvements to water quality while making drinking water systems more sustainable, High-chlorine concentrations reduced biofilm cell concentrations but selected for a distinct biofilm bacterial community and inorganic composition which led to higher discolouration when flushed. The study yielded much interesting information but it would be premature to change current practice without further data.
Re-dosing with pre-formed monochloromine.
When it is necessary to boost disinfection in a long distribution system this study shows that this can be achieved using pre-formed monocchloramine
. This study found that the current kinetic model used for drinking water application was not accurate for highly concentrated monochloramine and a simplified kinetic model was developed and successfully used to predict monochloramine stability. Hydrazine, a compound of health concern, might form at high monochloramine concentrations and high pH and needs to be carefully controlled.
Waterborne pathogens – detection and treatment
This book covers the issues and worldwide solutions of water treatment. It focuses on aspects of detection, identification, and removal methods of waterborne pathogens
. It addresses the issues of modern applications of scientific achievements such as biosensors or molecular tools in the detection of pathogens or monitoring the release of resistance genes into the environment.
Viable but non-culturable E. coli induced by low level chlorination have higher persistence to antibiotics .
Preparing for drinking water disasters
This paper proposes that exercises to test preparedness
should not simply test responses but should promote a learning environment and incorporate structured training exercises.
Phosphate dosing impact on microbes and discolouration in distribution.
Studies on a British distribution system showed that with phosphate dosing, turbidity responses were increased
, particularly from cast iron pipes. Differences in the taxonomic composition of both bacteria and fungi were also observed, emphasising a community shift towards microorganisms able to use or metabolise phosphate.
Longterm aging of polyethylene pipes
UKWIR held an on-line dissemination of results from a project involving exhuming and analysing test beds of plastic pipes and joints laid over 30 years ago and evaluating the long-term asset performance
, the associated risk of asset ageing and the effectiveness of improved electrofusion jointing initiatives. Overall, the likely lifetime of the pipe is substantially higher than the current design life of 50 years which is good news for the industry.
Using the Soil and Water Assessment Tool
it is possible to simulate metaldehyde
effectively using water industry historical data. Outputs from this research demonstrate the potential application of SWAT in large complex catchments where routine monitoring is in place, but isn’t designed explicitly for the purpose of predictive modelling.
Survival and resuscitation of Escherichia coli O157:H7 in the viable but nonculturable state after boiling or microwaving.
This study showed the survival of a small number of E.coli O157:H7 cells in the VBNC state after boiling for 1 or 10 min
or microwaving. Furthermore, the VBNC E.coli
O157:H7 cells regained growth at 37° C in culture media containing autoinducers produced by common non-pathogenic E. coli
, commonly present in the human intestine, and norepinephrine. This study highlights potential concerns for public health risk management of VBNC E. coli
O157:H7 in drinking water disinfected by heat treatment at point-of-use.
A rapid method for the detection of somatic coliphages
Somatic coliphages can be used as indicators of faecal pollution of waters
. Bluephage is a novel method which utilises a strain of E.coli
which cannot release β glucuronidase except when cells are lysed, which is brought about in this method by phage. The method allows detection of as few as 1 somatic coliphage in under 3.5 h.
Pyrazines as taste and odour contributors in drinking water
While geosmin and 2-methylisoborneol are the most studied earthy-musty odour-causing compounds in water, pyrazine and its alkyl and methoxy compounds possess similar odours. The widespread presence of earthy-musty-sweet pyrazines in source and drinking waters
on two continents, their poor removal during water treatment, and ng/L odor threshold concentrations confirm their potential to be T&O issues for consumers.
Downsized technology for Raman spectroscopy
Raman benchtop setups
can be up to a metre long but researchers have designed a system that can potentially replace these bulky benchtops with a tiny photonic chip that can snugly fit within the tip of a finger and is ten times more sensitive.
Removal of PFAS by GAC.
Studies on a full-scale water treatment plant In Sweden showed that the average removal efficiency of PFASs
ranged from 92 to 100% for “young” GAC filters and decreased to 7.0–100% for “old” GAC filters. it was concluded that prolonging the GAC service life by lowering the flow-rates after reaching the treatment goal could lead to a 26% cost-deduction.
Air scouring versus uniderectional flushing.
Work carried out in Quebec, Canada concluded that within the studied networks, the water requirements for air scouring
were approximately 8-fold less than for unidirectional flushing and did not significantly improve the hydraulic capacity of the cleaned pipes. (this is taken from the published abstract but does not seem to be a sensible conclusion
Cyanide risk in drinking water
DWI has isued Information Letter 05/2020
notifying water undertakers of the potential risk of the formation of cyanide above the PCV following chloramination.It requires appropriate monitoring to determine whether any specific works presents a risk. ( no reference is made to cyanogen chloride in this context)
Cancer risk and chlorination by-products
Naturalised faecal indicator bacteria.
In tropical to temperate environments, fecal indicator bacteria (FIB), such as enterococci and Escherichia coli
, can persist and potentially multiply, far removed from their natural reservoir of the animal gut. FIB isolated from environmental reservoirs such as stream sediments, beach sand and vegetation have been termed “naturalized” FIB. An additional theory suggests that some “naturalized” FIB diverged from enteric FIB many millions of years ago and are now normal inhabitants of the environment. It has been postulated that these environmental FIB belonging to the genera Escherichia
can be differentiated from enteric FIB by genetic methods.
Water quality indices for service reservoirs.
Three water quality indices
previously presented in the literature have been evaluated and used for the first time to assess the water quality of service reservoir designs optimised by different methods. This research is to enable designers to compare designs of service reservoirs that vary spatially and in size with regards to water quality performance and during optimisation procedures.
F-specific phage as indicators of faecal pollution
F-specific coliphages have been proposed as viral indicators of fecal pollution
. This study describes a new method designed to exclusively detect F-specific phages in which, when detected, the yellow medium turnsue. As low as one F-specific phage was detected in 3 to 5 hours by this approach and when the sample contained high phage concentrations, results were obtained in less than 3 hours.
E. coli O157:H7 cells can survive boiling or microwaving at viable but nonculturable (VBNC) state.
Microplastics and antibiotic resistance genes
Metaldehyde prediction using existing datasets.
Workers integrated existing water industry,datasets for the River Medway, uk with the open-access Soil and Water Assessment Tool (SWAT)
, to establish if these datasets could be used to effectively model metaldehyde in river catchments.. Outputs suggest that SWAT could be applied universally to catchments using existing water industry datasets.
Water supply infrastructure – aging and maintenance
Japanese workers have devised indices for evaluating deterioration of drinking-water distribution pipelines and maintenance management systems
for the pipelines. The indices are the percentage of old pipelines, the percentage of ineffective water, change in the number of technical staff per unit length of pipe, and the repair rate of water leaks . Using these indices, the evaluation result for Japan overall was a C (Caution) in terms of deterioration and Downward in terms of maintenance management.
Relationship between total suspended solids concentration and turbidity
Workers in Canada performed tests in the laboratory on a test loop and found that the ratio between turbidity and suspended solids (TSSC) may vary greatly between samples, up to 10 times during unidirectionalflushing sequences and 20 times during air scouring sequences. Particle origin, flushing method, and sampling time are all factors impacting the turbidity/TSSC ratio. They caution that total suspended solids should not be estimated from a single turbidity reading.
Pyrazines as potential causes of taste and odour in water.
THM exposure and pregnancy outcomes
Swedish workers conducted a nationwide register-based prospective study to assess whether gestational exposure to the four most common chlorination by-products [total trihalomethanes (TTHMs)] via tap water was associated with risk of small for gestational age (SGA), preterm delivery, and very preterm delivery. To date, this is one of the largest studies assessing drinking water TTHM-associated adverse reproductive outcomes, covering over half a million pregnancies.
The results of the present study
provide the evidence that CBP exposure via drinking water is associated with increased risk of SGA in areas with hypochlorite treatment, but not chloramine, potentially due to CBP formation differences. There was no clear association for preterm or very preterm delivery.
Urban water works and water cycle management: advanced approaches
Hard water, elasticity of arteries and heart disease.
This paper compares elasticity of arteries in consumers receiving soft or hard water
. Higher arterial stiffness (low flexibility of arteries) was determined for residents supplied with soft drinking water. The “absolute” difference between the arterial and actual age between the two evaluated groups of residents (soft vs. harder water) was nearly 5 years on average. The higher arterial stiffness and age of residents that consumed soft drinking water indicate the health significance of lower contents of Ca and Mg in drinking water as an environmental risk factor of cardiovascular diseases. Measuring arterial stiffness of residents in the areas supplied with soft drinking water can be used as a non-invasive approach in the prevention of cardiovascular risks.
Coronavirus in water environments.
The literature is awash with papers on all aspects of coronavirus and Covid 19. This literature review helps assess the current knowledge base and summarises the occurrence, persistence and survival data for coronavirus in water
. It also considers methods for the recovery of coronavirus from water. It concludes that there is no current evidence that human coronaviruses are present in surface or ground waters or are transmitted through contaminated drinking-water.
Micro-device for detecting bacteria in water
Scientists designed a next-generation miniature lab device that uses magnetic nano-beads to isolate minute bacterial particles
that cause diseases. The developers say “We can bring this portable device to a lake which has been contaminated by E. coli
. We will be able to take a few milliliters of the water sample and run it through our device so the bacteria can be trapped and concentrated. We can either quickly detect these bacteria in the device or release them into certain chemicals to analyze them" (this is not as yet an alternative to conventional bacteriological sampling and analysis.
Beware average log-reduction
Removing the novel coronavirus from the water cycle
Researchers have called for more research to determine the best ways to keep SARS-CoV-19 out of the water cycle
. They also suggest that developed nations should finance water treatment systems in the developing world to help prevent future COVID-19 pandemics.. During a 2003 SARS outbreak in Hong Kong, a sewage leak caused a cluster of cases through aerosolization.
Water and COVID 19
Sulphamic acid in water
Studies in Germany found Sulfamate occurs almost ubiquitously in major surface waters, mostly derived from discharges from sewage treatment works. Common drinking water treatment techniques, including ozonation and filtration with activated carbon, are not capable of removing sulfamate. About 30% of samples from ground and surface water exceeded the predicted no-effect concentration (PNEC) of sulfamate
, and thus effects of sulfamate on the aquatic ecosystem of wastewater-impacted waterbodies in Germany cannot be excluded so far. However toxicological estimations suggest that no risk to human health is expected by concentrations of sulfamate typically encountered in tap water.
Breaking down PFASs
Per- and polyfluoroalkyl substances (PFASs) contain bonds between carbon and fluorine atoms considered the strongest in organic chemistry. In the presence of excess elctrons these bonds have been shown to be readily breakable
.The workers speculate that in a real water treatment scenario, the excess electrons could come from metal-containing compounds placed in the water under ultraviolet radiation. The electrons from these compounds will interact with the PFA molecules and break them.
Quantitative microbial risk assessment of Greywater on-site reuse
A framework for real-time disinfection plan assembling for a contamination event in water distribution systems (WDS).
This paper proposes a framework for assembling a disinfection plan in real-time
by (1) partitioning a WDS into a number of district metered areas (DMAs), (2) generating a solution region for each of the DMAs, and (3) assembly of an effective decontamination plan using solution region generated.
Aging and maintenance assessment of water-supply infrastructure
Japanese workers have devised indices for evaluating deterioration of drinking-water distribution pipelines
and maintenance management systems for the pipelines. The indices are the percentage of old pipelines, the percentage of ineffective water, change in the number of technical staff per unit length of pipe, and the repair rate of water leaks.
Microcystin background document for the development of the Guidelines for drinking-water quality and Guidelines for safe recreational water environments: Available for comment
WHO is preparing a number of background documents for selected chemical hazards in water. These will inform the development of the second addendum to the fourth edition of the WHO’s Guidelines for Drinking-water Quality (GDWQ). The cyanotoxin background documents will also inform the revision of the Guidelines for safe recreational water environments. The revised background document is ready for review for microcystin. Comments on the background document should be sent to
by 17 April 2020 and can be accessed here
Dissolved organic carbon threat to groundwater.
A study of a global dataset of 9404 published and unpublished groundwater dissolved organic carbon (DOC) concentrations from aquifers in 32 countries across six continents.
The study forecasts elevated DOC concentrations
because of projected changes in temperature and rainfall due to climate change, as well as increased urbanisation.
Better leak detection.
Framework for planning water distribution system decontamination
This paper proposes a framework for assembling a disinfection plan in real-time
by (1) partitioning a system into a number of district metered areas (DMAs), (2) generating a solution region for each of the DMAs, and (3) assembling an effective decontamination plan using solution region generated. When applied to 3 contamination events the approach significantly reduce the response time; improved the quality of the decontamination plan;, and provided a model for optimizing the resource allocation.
Detection of Pathogens in Water Using Micro and Nano-Technology
Novel desalination process.
Researchers at the University of Bath have developed a revolutionary desalination process
that has the potential to be operated in mobile, solar-powered units. The process is low cost, low energy and low maintenance, and has the potential to provide safe water to communities in remote and disaster-struck areas where fresh water is in short supply.
Unlike the classical desalination process, where water rather than salt is pumped through a membrane,this process pumps salt out of seawater. The process is as yet only at the proof of conceptstage.
Groundwater watch list for substances of emerging concern.
This multinational paper shows how in the absence of a policy for substances of emerging concern in groundwater, and in the face of insufficient data, a group of states, agencies and researchers have come together to try and fill this important policy gap on a voluntary basis. It describes the approach that has been developed through a voluntary initiative as part of the EU CIS Working Group Groundwater
to establish the voluntary EU Ground Water Watch List.
Saliva testing as an alternative to pathogen culture
Implications of recent Water,Sanitation and Health (WASH) and nutrition studies.
In 2018, the WASH sector was surprised by three new high-quality studies
that showed little or no impact of selected WASH interventions on reducing childhood diarrhoea and stunting. Some practitioners, researchers and funders have reacted by questioning the value of investing in WASH compared to other public health interventions and how future WASH implementation can be improved to achieve greater health gains. These studies are not a call to stop working together but rather to programme together more effectively. This paper discusses where approaches to WASH need to be better focussed and suggests that provision of “improved” water and sanitation technologies could only deliver modest health gains,and that more substantial health improvements can only come with entire community coverage with higher service levels.
Adverse birth outcomes and cancer risk due to nitrate in United States drinking water.
Meta-analysis of eight studies assessing nitrate in drinking water
and CRC supports a health benchmark of 0.14 mg/L. The study concludes that 2,300 to 12,594 nitrate-attributable cancer cases occur annually in the U.S., of which 54-82% are colorectal cancer .This costs $1.5 to $6.5 billion dollars per year.
Managing microbial risk in drinking water systems.
Water Research Australia has updated its “Good Practice Guide to the Operation of Drinking Water Supply Systems for the Management of Microbial Risk” which serves as an evaluation and benchmarking tool.
The guide is only available to members of WaterRA.
Impact of changing from chlorinaation to chloramination on lead in water.
Microbial source tracking using Bacteroides
Online fluorescence spectroscopy for the real-time evaluation of the microbial quality of drinking water
Researchers at Harvard Medical School and the New York State Department of Health have discovered how a common plasticizer associated with human reproductive abnormalities
likely does its damage at the molecular level. Various U.S. federal and state agencies responded by passing laws limiting the percentage of DEHP and other phthalates in children's toys, food packaging, drinking water
and other items. DEHP has been banned in Europe since February 2015.
Water governance-could less sometimes be more?
Researchers analyzed water governance regulations
in six European countries from 1750 to 2006 and show that rules designed to improve resource management come into conflict in the long run, creating an equal number of positive and negative effects until the system falls apart.
Potable water reuse without reverse osmosis.
Pilot plant studies
demonstrated that ozone with biological filtration could achieve potable water quality criteria, without the use of RO, in cases where nitrate is below the MCL of 10 mg nitrogen per liter and total dissolved solids are below the SMCL of 500 mg per liter. Trials with a range of blending ratios showed that finished water from the direct reuse plant had no detections of microorganisms even at 100% . However, exceedances of one or more quality standards were observed at blends above 15%.
Bacteria and algae produced omega-3 fatty acids from microplastics
C labelled polyethylene, workers in Finland were able to demonstrate
that aquatic micro-organisms can produce, biochemically upgrade, and trophically transfer nutritionally important biomolecules from PE-MP.
New method for water filtration
Workers in the USA have developed networks of artificial membranes
which could prove useful for separating salt from water, a filtration process that is currently inefficient and costly. The new membrane has shown impressive desalination properties
, exhibiting far more selective salt and presumably other contaminant removal when compared with existing processes.
The method is a thousand times more efficient than current desalination processes in terms of its selectivity and permeability.
Identification of sources of faecal pollution
106 samples from 4 sources were collected in 5 European regions and 30 faecal indicators and source tracking markers were evaluated
, including E. coli
, enterococci, clostridia, bifidobacteria, somatic coliphages, host-specific bacteria, human viruses, host mitochondrial DNA, host-specific bacteriophages and artificial sweeteners. Models based on linear discriminant analysis (LDA) able to distinguish between human and non-human faecal pollution and identify faecal pollution of several origins were developed and tested with 36 additional laboratory-made samples. With 5 variables the model correctly classified all the fresh faecal samples from 4 different sources.
Novel water purification process - the first example of magnetic polyoxometalate‐supported ionic liquid phases (magPOM‐SILPs) and their use in water purification.
Strengthening drinking-water surveillance using risk-based approaches
WHO has released a publication which provides a rationale for decision-makers to promote and support uptake of risk-based approaches in regulations and surveillance practice
. It has been designed around six key messages that underlie the concept of risk-based approaches in drinking-water surveillance and is supported by practical examples for illustration purposes.
Impacts of water quality on the corrosion of cast iron pipes
Switch of source water in iron mains may induce “red water” episodes. This study investigated the impacts of water quality on iron release
, dissolved oxygen consumption (ΔDO), corrosion scale evolution and bacterial community succession in cast iron pipes. The paper proposes a water switch strategy to minimse risk of discolouration.
Antimicrobial resistance in groundwater
A review of 70 peer-reviewed studies
found that 80.2% ± 29.0 and 57.2% ± 36.8 of aggregated groundwater isolates were resistant to ≥1 and ≥3 antimicrobials, respectively. Where bacteria were present, antibiotic resistant bacteria (ARB) were identified in 76.9% ± 33.7 of individual wells and springs. The reviewers consider that their results leave little doubt that groundwater represents a major global reservoir for ARB.
Formation and removal of disinfection byproducts
Having developed high sensitivity simple methods for the analysis of trihalomethanes (THM4), iodinated-trihalomethanes (I-THMs), haloacetic acids (HAAs), bromide, iodide and iodate,these workers showed that in a full-scale treatment plant I-THMs were constantly formed independently of iodine concentration
. They also showed that bromoacetic acid accounts for 60% of the relative toxicity of 17 DBPs.
Reluctance to accept recycled water.
An interesting Californian study has shown that consumers may accept the safety of, and need for, recycling of water
, but are still reluctant to accept it because of “disgust” at the reality.