Learn the ins and outs of adenosine triphosphate for the water and wastewater industry
What is Adenosine Triphosphate (ATP) exactly?
Adenosine Triphosphate, or ATP for short, is the primary molecule for transferring and storing energy in all living cells, from human and animal cells to microbes like bacteria.
ATP degrades quickly when a cell dies. If water contains a high concentration of live organisms, large amounts of ATP will be detected.
ATP can be used in water treatment to detect and monitor microbial contamination.
How is biomass quantified using ATP?
Using ATP to measure biomass in water is a rapid routine procedure that measures the concentration of cellular-ATP. ATP can be found in all living cells, including algae, protozoa, bacteria, and fungi.
When cellular ATP is present, it indicates that there is active microbial contamination in water. Note that ATP can’t be used to detect or quantify non-biological matter.
How is ATP used in water treatment?
ATP can be used in a number of water treatment applications, including drinking water systems, industrial water plants, wastewater treatment, and seawater desalination plants.
Detecting contamination in drinking water systems
Our water distribution systems need to be free from microbiological growth, which can result in microbiologically induced corrosion in both storage tanks and pipelines, as well as biofilm formation.
Using ATP to quickly detect live microbes and indicate hot spots for microbial proliferation can prevent infrastructural damage. Because ATP testing is so quick, providing almost instant results, it is ideal for this purpose.
Contamination in drinking water systems can be harmful to human health. Bacteria can cause cholera, typhoid fever and diarrhea, and can even lead to death. Using ATP to monitor and detect microbiological growth can ensure that microorganisms are removed from drinking water before it is distributed to homes. ATP is capable of detecting even low levels of microbial contamination, and can ensure action is taken before the problem becomes out of control.
Optimizing the aeration process in wastewater systems
Aeration takes up more than 50% of energy consumption in most wastewater treatment systems. Even slightly optimizing the aeration process can significantly improve energy consumption and help treatment plants spend less on the same processes.
Adding dissolved oxygen sensors or replacing old aeration systems with upgraded models can improve energy consumption. Using solids optimization is another, more affordable option.
The efficiency of oxygen transfer is affected by the concentration of suspended solids in the aeration system. Decreasing these suspended solids can therefore increase the efficiency of oxygen transfer, and less air is needed to provide the same amount of dissolved oxygen. As these suspended solids are made from living and dead biomass, ATP can be used to measure the amount of total active biomass present, allowing for a more efficient aeration process.
Monitoring influent toxicity
In wastewater treatment plants, microorganisms can be killed by influent toxicity from wastewater streams. Not only can toxic materials kill active biomass, but they can also impact the effectiveness of wastewater treatment. ATP can be used to quantify influent toxicity in a testing process known as biological stress index. In this test, the ratio of dissolved to total APT is measured. Dead or dying biomass is linked to dissolved ATP. Therefore, if the biological stress index increases, it's a sign that toxicity has increased.
Wastewater treatment plants that treat more than one influent stream can especially benefit from biological stress index. These plants can track toxicity to a single stream and take corrective measures to prevent this toxicity. Bioreactor toxicity can also be tracked with biological stress index. With routine ATP monitoring, operators will be alerted to upsets caused by toxicity before they can even be seen in water. Because of this, operators can proactively deal with toxicity issues, rather than waiting until the problem is more serious.
Preventing the fouling of membranes in seawater desalination plants
When seawater forms a layer of biofilm over the reverse osmosis membranes in seawater desalination plants, it can reduce water flow and result in membrane biofouling. Rather than treating biofilm formation, it is best to prevent it altogether by using a pretreatment that greatly reduces the concentration of biomass in seawater traveling into the reverse osmosis system.
To continually monitor sea water and give an indication of whether pretreatment applications are working, ATP can be used. Seawater desalination plants can work to proactively treat membrane biofouling with the data provided by ATP testing, rather than simply reacting to the problem.
ATP assays can also be used to reduce the cost of replacing RO membranes that have been damaged by membrane biofouling. Using ATP to detect biomass, and adjusting pretreatment accordingly, can save the cost and time spent cleaning or replacing RO membranes.
Measuring the effectiveness of biocide treatments
Industrial water facilities may get their cooling water from a surface water source, like a lake or a river. These water sources commonly contain microorganisms, which, in high quantities, can potentially damage infrastructure. A high bioload may cause microbiologically induced corrosion, clogging and blockages, and reduced efficiency of heat transfer.
Biocide is a type of treatment that can reduce microorganism presence in cooling water. ATP testing can be used to indicate whether a biocide treatment is capable of diminishing bioload. If the testing indicates little success, the treatment will need to be altered or intensified.
Using ATP to measure the effectiveness of biocide treatments can also prevent the buildup of bacteria like Legionella in water storage tanks and cooling towers. If bioload is creeping up to dangerous concentrations, action can be taken to prevent a Legionella outbreak.