In the UK, we are fortunate to have the luxury of water running directly into our homes and buildings.
But how does it get there?
Water passes from rivers, reservoirs and lakes into public treatment facilities. When the water is at the treatment plant, it is cleaned and filtered. From here, it is distributed to homes, schools, hospitals, and commercial and industrial buildings.
At this point, the water is usually fresh, clean and safe. But, it may not be contaminant-free.
The entire water distribution system is prone to multiple species of bacteria, algae, invertebrates and viruses. Even perfectly safe water contains millions of non-pathogenic microbes in every glass.
Some of these contaminants are harmless to human health. However, some are still dangerous.
Pathogens such as E.coli, Giardia, and Cryptosporidium can cause gastrointestinal problems and flu-like symptoms.
There is also the risk of Legionella bacteria, which can lead to the potentially fatal Legionnaires’ disease.
The way water is supplied to our buildings, the quality of the water we drink, and the way factories, plants and businesses store and distribute their water, are therefore protected and controlled by a range of regulations, treatments and processes.
And businesses have a responsibility to meet these requirements.
Get it wrong, and there can be critical damage to performance and reputation. and you can critically damage your performance and reputation.
Get it right, and you can dramatically improve your safety records, operational efficiencies and the quality of your customers’ and employees’ experiences.
Drinking water quality is something we take for granted in the UK. But it is still the preoccupation of employers, site facility managers and water hygiene technicians.
As we’ve seen, drinking water sources may be subject to contamination. Especially if your drinking water is fed from an alternative source, such as a borehole.
The greatest risk to human health is from waterborne pathogens, viruses and infections.
These exist primarily between water entering our buildings and the building water distribution system within it, as well as in the last few metres before the point of delivery, i.e. taps and showers.
Some microbes naturally exist in our water distribution systems. But they only cause illness to humans in certain conditions.
If microbes such as E. coli are found in water, it indicates that pathogenic microorganisms may have entered the water distribution system.
A common characteristic of microbiological communities in water distribution systems is, given the right conditions, their propensity to form biofilms. These can become highly attractive host environments for opportunistic pathogens.
These opportunistic pathogens, such as those listed below, can cause infection, especially in children and vulnerable people with weak or impaired immune systems.
Many biofilms in water distribution systems pose no significant threat to human health. But they can still cause physical damage, such as corrosion of pipes and blocking intake valves.
These biofilms can also break down chemicals used to minimise microbial growth, while others may release nutrients that help sustain pathogens in water distribution systems.
Common alternative drinking water treatment strategies often target biofilm formation, without sometimes fully understanding what microbes may exist within your own water distribution system.
Water treatment chemicals such as chlorine, for example, can be used to kill pathogens.
However, some pathogens, such as mycobacterium avium, are resistant to chlorine. Some disinfectants may also further promote the growth of pathogens.
The only way to check the water quality is being maintained is to monitor the microbiology and bacteria in the water. If required, the most appropriate methods of primary disinfection and secondary disinfection can then be selected.
Water pipe material utilised will often vary from building to building and within individual systems. The fixings and installation quality can dictate system integrity, corrosion rates, flow and pressure.
The composition and condition of the pipes can influence what chemicals may be released into the system and the types of bacteria that colonise within water distribution systems and on pipe surfaces.
Some pipe materials may break down and release biosource compounds, such as iron, hydrogen and phosphate, that can encourage biofilm growth and bacteria to multiply.
Biofilms coating the interior surfaces of water distribution pipes usually develop slowly and can take years to reach maturity. Older pipes are therefore more prone to developing large amounts of scale and rust.
Water softeners can be used to reduce corrosion and scale.
Water treatment chemicals can also be used to coat the interior of water distribution pipes, which controls corrosion and scale and destroys biofilms.
Some phosphates, for example, achieve this by stimulating bacterial biofilm growth and re-regrowth. Some silicates, on the other hand, work by inhibiting biofilm growth.
A biofilm is a layer of microorganisms which forms on surfaces in contact with water. The presence of biofilms in water pipe networks can have a negative effect on water quality and cause operational problems.
Biofilms can be responsible for increased bacterial levels, reduction of dissolved oxygen, taste and odour changes, as well as problems due to iron or sulphate-reducing bacteria and reduced life of materials.
Microorganisms that form biofilms include bacteria, fungi and other organisms such as larvae and crustacea.
One of the biggest concerns with biofilms in drinking water systems is the growth of coliform bacteria in the pipe network.
If there is a break or a leak in a pipe, it can lead to low-pressure events which cause bacteria to cling to surfaces.
It may also encourage biofilm growth. And any sediment that enters the system can serve as a source of nutrients that cause bacteria to grow.
Alterations to the pipework can also impact the system integrity.
The type of storage facility can impact hydraulic pressure and water age.
Water tanks are common habitats for water microbes. Systems with water tanks that do not turn over frequently can encourage microbiological activity.
This can cause the water supply company’s disinfectant concentrations to drop and sediment to accumulate and influence microbial growth.
The source, stability and temperature can all impact water quality.
Source water
Nutrients in the water can influence water microbiology. Microbes can feed on the compounds, carbons and nutrients found naturally within water. This becomes more important with water re-use as disinfection concentration becomes impaired over time.
Chemical stability
Once water has been treated, it changes and can start to respond in ways that favour microbiological growth. For example, residual disinfectant effectiveness can decrease at rates depending on water temperature and disinfectant dosing.
Temperature
Temperature can heavily influence the microbiology in water. Different organisms respond differently to changes in temperature and seasonal temperature changes. This is why disinfection regimes are often stepped up or changed in hotter periods.
There are increasingly sophisticated and sensitive water testing and laboratory analysis services that can help determine what may be happening in your water chemistry. This can lead to better decision-making when it comes to water treatment.
Every business needs to understand and carry out their legal duties regarding the control of legionella – the bacterium that causes Legionnaires’ disease, a lung infection that can be fatal.
In the UK, there is an obligation for anyone responsible for maintaining water systems in buildings to mitigate the risk of Legionella.
This is supported by prosecutions and fines for duty holders found to have failed to comply with regulations and endangered human health.
Employers, Health and Safety managers, and those in control of premises with a duty of care for others are required to:
A Legionella Risk Assessment is obligatory - it's a legal requirement under the Health and Safety at Work Act 1974. It also has to be conducted by a suitably trained person who would be regarded as "competent" in a court of law.
Consider a specialist company offering Legionella Risk Assessments or a Legionella Review of Risk Assessments carried out in-house. The member directory of the Legionella Control Association is a good source of information.
Legionnaires’ disease: the control of legionella bacteria in water systems is an approved Code of Practice (ACOP). The current edition is L8 (fourth edition) and was published in 2013. It is commonly referred to by the shortened acronym ACoP L8.
Business owners can face prosecution for breaching health and safety law if they don’t follow the advice provided in the code.
ACOP L8 is “aimed at duty holders, including employers, those in control of premises and those with health and safety responsibilities for others, to help them comply with their legal duties in relation to legionella. These include identifying and assessing sources of risk, preparing a scheme to prevent or control risk, implementing, managing and monitoring precautions, keeping records of precautions and appointing a manager to be responsible for others.”
Disinfection is an important step in ensuring that drinking water is safe.
UK water companies are required to meet the EU Drinking Water Directive by disinfecting public water to the point of supply. They have to kill or inactivate disease-causing organisms in the water supply.
There are two principles of disinfection:
Primary disinfection: Once the water has been filtered, a disinfectant such as chlorine or chloramine is added in order to kill any remaining bacteria and viruses.
Secondary disinfection: Provides enhanced protection by preventing the regrowth of microorganisms harmful to human health between incoming public water supply to your building and the water distribution system inside your building right up to point of use, i.e. taps, showers etc.
There are many uses of water in industry. Large quantities are required for the cooling of products and equipment, for process needs, for boiler feed, and for sanitary and drinking water supply.
But water entering an industrial plant needs to be treated before it can be used in industrial processes.
If unclean water is used in the production process, it can negatively affect product quality.
Bacteria in the water can also reduce the efficiency and operating life of boilers and other systems.
And when left untreated, bacteria can grow, including legionella.
Industrial water treatment ensures the water quality is suitable for use. It also reduces energy consumption and improves operational efficiency.
Industrial water treatment can benefit a wide range of industries, including many areas of manufacturing, food and beverage, healthcare, and pharmaceuticals.
There are four main problem areas that industrial water treatment seeks to manage:
Scaling is the build-up of unwanted material on solid surfaces.
Scale deposits are formed when the chemistry and temperature conditions are such that the dissolved mineral salts in the water precipitate.
The scale deposits can be free-moving, like fine silt, or can form in layers on the metal surfaces of the system.
In cooling towers, scale can be a harbouring ground for bacteria to breed, including legionella.
In closed systems, the primary problem with scaling is the inhibition of the heat transfer process and blocking of tubes, causing low flow.
Scale inhibitors and water softeners can be used to minimise the build-up of scale.
Corrosion is a naturally occurring process that converts a refined metal (such as iron) to oxidise or causes a refined metal, which gradually causes the integrity of the plant equipment to become compromised.
The problems caused by corrosion are similar to scale. But corrosion can also lead to leaks, which can result in catastrophic failures within a pressurised system.
The consequences of corrosion are many and varied:
Corrosion inhibitors can be added or pre-treatment used to reduce the rate of corrosion.
Microbes thrive in untreated cooling water. Fungal spores and other material can collect in the water if not treated with biocides.
The severe and potentially fatal Legionnaires’ disease has also often been associated with unmanaged water systems.
To control microbiological activity:
Certain industrial and manufacturing processes can cause substances to get carried away with water when it is disposed of.
The presence of these substances can be toxic if recycled back into the plant without being treated.
In many cases, effluent water from one process can be reused in another process if given suitable treatment.
Industrial water treatment can be broken down into three primary areas.
Boiler water systems are an essential component in many industrial applications where the primary purpose is to transfer energy from one part of the system to another.
If a boiler system is not maintained or the water is left untreated, it can lead to serious issues that will affect its integrity and performance.
A well-managed boiler water treatment programme will:
Boiler water treatment solutions include:
Cooling systems are susceptible to corrosion, scaling, fouling and microbiological contamination.
In fact, many outbreaks of Legionnaires’ disease have been traced to poorly managed cooling towers.
A well-managed cooling system water treatment programme will:
Cooling system water treatment solutions include:
Closed circuit systems provide heating or cooling to buildings, manufacturing and industrial processes.
They are used in a variety of industrial processes, most commonly in heating systems.
They have a number of advantages over open water systems, including greater efficiency and lower maintenance requirements. But it would be wrong to think of them as maintenance-free.
As a ‘closed loop’ or ‘closed system’, they are not normally susceptible to outside contaminants.
But, they can still be affected during routine maintenance and refurbishment work by factors such as corrosion and microbiological contamination.
Closed circuit system water treatment solutions include:
Testing of water quality is an essential part of the industrial water treatment process, especially in closed circuit systems which are impossible to view from the inside.
Poor management can lead to scale and corrosion issues, reduced efficiency and even damage to critical systems.
Monitoring can be completed by physically removing and testing representative samples of the water. Inline and online monitoring systems are also now becoming more prevalent.
There are two elements to maintaining an efficient closed circuit water system:
Performing water analysis on a regular basis can help you keep on top of your closed system water treatment levels.
A BSRIA Closed System Water Analysis - BG 50/2015 is a comprehensive set of tests that cover a full range of chemistry and micro-analysis.
A standard closed system would typically look at:
Monitoring and control of water systems is essential to ensure the water in your buildings is safe for drinking and use in industrial processes.
Monitoring water treatment systems typically involves conducting chemical tests and comparing the results to specific chemical control limits.
The testing frequency can vary from once per month, to once per day to even once per hour.
Water testing is an essential part of asset management, ensuring system integrity, water hygiene risk management and Legionella control.
Routine water testing allows duty holders to monitor for contaminants, corrosion and scale, and identify when a new approach to treatment is required to tackle these problems effectively.
What to test for:
Deciding which disinfection solution is right for you depends on a number of criteria, including your objective, application, water usage, and flow rates.
In all likelihood, a combination of techniques will be required for your building or water distribution system.
The following water treatment techniques can be employed to deal with bacteria in water:
Chlorine is added to water for disinfection and control of microbiological contaminants.
It is added to water by public water companies making it safe to drink.
Today, forms of chlorine such as Ultralox40® are widely used as methods of disinfection and secondary disinfection of water distribution systems within buildings.
UV disinfection is a simple, low cost and popular method of water disinfection.
It is efficient at killing bacteria, viruses, fungi, protozoans and cysts that may be present in water. But cannot be used to remove gases, heavy metals and particulates, and bacteria can hide behind larger debris.
UV is often used in conjunction with other water disinfection methods.
Ozone is produced when oxygen is exposed to high-voltage current.
It can destroy viruses, bacteria and microbiology, while also removing iron, sulphur and manganese.
Ozone is a quick disinfection method and then rapidly decomposes, cutting down on the introduction of harmful disinfection by-products and foul tastes or odours associated with some chlorination.
Chlorine Dioxide (ClO2) production is a particularly effective microbiological control, Legionella control and primary and secondary water disinfection measure.
For reasonable quantities, it requires generation and is suitable for biofilm eradication, membrane systems and filtration, water distribution systems, cooling towers, hospitals, hotels, horticulture, breweries, dairies and sites with hazardous chemical restrictions.
ClO2 should be the preferred method of ensuring purity in your water system. This is because it does not form undesirable disinfection by-products, has 2.6 times the oxidative capacity of chlorine, and will react in a third of the time - meaning at typical treatment levels, it is less corrosive to pipes and equipment.
Sodium Hypochlorite (NaOCI) is one of the most commonly used compounds for water purification, especially across large scale surface purification, bleaching, odour removal and water disinfection in cooling towers.
It is a cost-effective method, simple to dose, and can be safely stored and transported. However, it can be hazardous and corrosive in concentration and does not deactivate Giardia Lambia and Crptosporidium. It is most effective in waters <ph8.
Today, there are a variety of innovative technologies that can improve the safety and reliability of your water systems.
These include:
The GENOX generator produces a colourless liquid which is generated on-site and requires no mixing or handling of toxic chemicals. Direct electrolysis of brine, creates an oxidant NEUTHOX® on demand.
Advantages:
Limitations:
A universally effective primary and secondary disinfectant, that doesn’t have the usual limitations of chemical mixing, handling or storage.
Advantages:
Limitations:
A universally effective primary and secondary disinfectant, generated using a patented Safe Generation per Batch (SGB) technology.
Advantages:
Limitations:
Ozonation is a water treatment process that destroys microorganisms and degrades organic pollutants through the infusion of ozone, a gas produced by subjecting oxygen molecules to high electrical voltage.
Advantages:
Limitations:
Ultraviolet (UV) radiation is generated by a special lamp. When it penetrates the cell wall of an organism, the cell’s genetic material is disrupted and the cell is unable to reproduce.
Advantages:
Limitations:
Ultralox40® is a regulated, stable, and highly effective low concentration form of chlorine that works as a fast-acting biocide.
Advantages:
Limitations:
WCS Group is a trading name for WCS Environmental Ltd, registered in England and Wales (Number 02184649) at 20 Grosvenor Place, London, SW1X 7HN. Head Office – 17 Wheatstone Court, Waterwells Business Park, Gloucester, GL2 2AQ. WCS Group is a Marlowe Critical Services Company owned by Marlowe plc. 2020© WCS Environmental Ltd.
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