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Detection of bacteria to measure quality of water

Detection of bacteria to measure quality of water


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I have been working on a science project were I have built a water filter.

To prove that it works I would need to test if there are bacteria in a sample which has been treated vs a sample that hasn't been treated.

I really just need to know if there are bacteria not how many. I looking to do this at home.


IF you are looking at a much faster technique but don't mind spending a bit and have some research equipment access, there are ways by which bacterial contamination can be detected by measuring ATP (Adenosine tri-phosphate). See this research publication. There are commercial kits available which you can use: Here is one of them by Thermofisher.

Again, this is only if you have access to the research equipments and funds.


Detection of bacteria to measure quality of water - Biology

Microorganisms in waters are of great public concern and the trouble of detecting them in water is even well known.

Traditional culture methods are retrospective and tend to underestimate the actual microbial load.

Consequently, the use of procedures that provide rapid results are of fundamental importance.

A variety of analytical approaches has been proposed for the rapid detection of microorganisms in water.

The development of new and improved methods for microbiological water analysis is a continuing process.

Some of the most interesting and promising analytical techniques for water microbiological analysis are described.


Microbial biosensor designed to evaluate water toxicity

Researchers of the Environmental Microbiology Group of the UAB Department of Genetics and Microbiology have developed a paper-based biosensor covered with bacteria to detect water toxicity. This is an innovative and inexpensive biological tool which can be easy to use in economically restricted areas or developing countries.

The detection of toxic contaminants is an essential element of analysis and control of water quality, something very needed in an increasingly urbanised and industrialised world. Chemical analysis techniques are of great utility in determining specific substances, but are limited when used to analyse complex samples which can contain multiple contaminants. In this sense, the use of biosensors is appropriate, in which they measure the effect samples have on a biological element, such as enzymes or proteins, or on a vital parameter of an indicator organism.

"The innovation provided by our sensor is based on the use of absorbent paper matrices with entrapped bacteria with the aim of conducting colorimetric measures of toxicity," explains UAB researcher Ferran Pujol, who conducted this study as part of his PhD thesis. In this work, researchers used Escherichia coli (E. coli) cells were used as model bacteria. The paper was recently published in Analytica Chimica Acta.

The detection technique proposed and validated by researchers is quick and simple. In fact, its mechanisms is similar to that of paper strips used to measure the pH of water. The samples analysed are added to the matrices together with the colouring agent ferrocyanide, which ranges from yellow to transparent when breathed in by the microorganisms.

The paper changes colours according to the intensity of the cell metabolism of the bacteria, inversely proportional to the toxicity of the sample: the more the colour changes, the less contamination detected. These changes can be measured with optical techniques, by analysing the image or with the naked eye.

The bioassay, which researchers have applied a patent for, detects any contaminant which can be toxic for the microorganisms after some 15 to 30 minutes of coming into contact with the cells (time taken to conduct the test), such as heavy metals or hydrocarbons such as petroleum or benzene. The technique can be applied to both natural waters and urban and industrial wastewater.

Using a material such as paper and without the need of complex tools makes this biosensor a simple and inexpensive technique which can be used to detect toxicity in contexts of economic restrictions or in developing countries, researchers indicate.


Detection of bacteria to measure quality of water - Biology

Bacteria are a natural part of the water: purified drinking water contains about 20’000 to 300’000 bacterial cells per milliliter. Increasing water demand and deteriorating natural water quality are a constant concern, particularly for the water treatment industry. Selective laboratory measurements are intermittent and are no longer sufficient to current quality standards. Permanent water monitoring has become a necessity.

Measurement systems and sensors for continuous on site monitoring have become increasingly important and already represent the state of technology for many water providers. These online measurements systems cover physical, optical and chemical parameters such as temperature, flow, pressure, conductivity, turbidity (NTU), pH, monochloramine, fluorine compounds and nitrates.

Missing so far was a reliable on site measurement that captures bacterial activity of the water within short intervals and records the general and hygienic microbiological state.

Online Bacteria Analyzer

The Online Bacteria Analyzer is the first autonomous measurement device that meets the complex requirements for the use along the entire water production and distribution chain. All required preparation steps have been integrated into a single, process suited device which provides measured data and results online.

It is designed for continuous operation, 24 hours a day, 7 days a week. The device measures without human intervention for at least two weeks, then consumables like sheath fluid, pure water and stain have to be replaced. OBA’s fail-safe system handles occurring interferences and compensates them.

Flow Cytometry

By staining water samples with DNA dyes, the flow cytometry technology can differentiate between organic cells and DNA-free, inorganic particles. SYBR green induces a green fluorescence on DNA or RNA. Propidium Iodide can permeate the damaged membrane of dead cells, but cannot permeate those of intact and living cells.
The stained cells and particles are then streamed through a glass capillary where they are illuminated by a focused laser beam. The scattered light of cells/particles and the emitted fluorescence of the dye are then collected through appropriate detectors.

OBA’s detection is based on this flow cytometry technology. The device distinguishes itself due to its optical design, the high sampling rate of the optical sensor with 2 MS/s or 4 MS/s and the 24 bit dynamic range of its signal converters. Due to the OBA SmartDetect™ detection algorithm it is no longer necessary to define a traditional signal threshold. OBA is immune to zero point offsets, caused by varying samples.

Measurement Results

Individual water samples differentiate by their microbiological structure. After the measurement of a sample the results of two of the different scatter and fluorescence detectors can be combined to so called dot-plots.

By defining regions inside the dot-plots (gating) Information about specific cell types can be retrieved like the total cell count (TCC), the amount of LNA (low nucleic acid cells) and HNA (high nucleic acid cells) and alive and dead cells.

Traditional methods at laboratories to determine the bacteria that form colonies of heterotrophic bacteria (HPC or heterotrophic plate count) take up to 48 or 72 hours until there are results. OBA reduces measurement time significantly: precise, real and high resolution results on the microbial state of the water are available within minutes.

Monitoring

OBA online monitoring is based on comparing the results of two or more consecutive measurements. Measuring the same sample source under constant conditions will result in minor deviations only. In case of a real event, such as an infiltration by rain water, contamination by manure or a malfunction within the treatment process the results inside the scatter and fluorescence plots will change immediately.

By exceeding predefined thresholds a warning or alarm will be triggered: acoustic, optical, by email, by output signals to a logic controller (PLC) and by ethernet (Modbus/TCP). One can respond quickly to microbiological events.

Software

The Online Bacteria Analyzer has a powerful and comprehensive control and analysis software, focusing on the ease of use without limiting possibilities for the user. Flexibility was and is considered as important Feature. By using predefined Templates one can start using the OBA in no time. The software application offers a wide variety of usage Ranging from a basic user to start a single measurement or measurement-sequences to the power user that parametrizes sample preparations and measurements or defines detailed processes and sequences.

Furthermore the software application includes an extensive analysis toolset to evaluate data by given criteria after each measurement.

The integrated database guaranties save data handling and backup. By using the OBA Data Analyzer application data can be access remotely and then processed in a desktop environment.


Fecal Indicator Bacteria and Sanitary Water Quality

Naturally some microorganisms have learned to live on or in the human body. Many of these microorganisms do no harm, and are even beneficial because they compete with other microorganisms that might cause disease if they could become established in or on our bodies. The fecal indicator bacteria are such microorganisms they are normal inhabitants of the gastrointestinal tract of humans and many other warm-blooded animals and in general, they cause no harm.

A few microorganisms (called pathogens) can cause disease in humans. In order to cause disease, a pathogen must successfully invade some part of the body and either produce more of itself or produce a chemical (usually called a toxin) which interferes with normal body processes. Whether or not a pathogen is successful in causing disease is related to the health of the individual and the state of his or her immune system, as well as to the number of pathogen cells required to make the person ill. Some pathogens can cause disease when only a few cells are present. In other cases, many cells are required to make a person ill. Children and elderly persons are more susceptible to many pathogens than are young or middle-aged adults.

Some pathogens live out their lives in the soil and water and only cause disease under unusual circumstances. The microorganism that causes tetanus is an example. This microorganism (a bacterium named Clostridium tetani) lives normally in the soil. Clostridium tetani grows in the body only in deep puncture wounds where air cannot penetrate (termed anaerobic). In this environment it produces a toxin which spreads throughout the body and may cause paralysis. Other pathogens are more closely associated with humans and other warm-blooded animals. These pathogens are transmitted from one organism to another by direct contact, or by contamination of food or water. Many of the pathogens which cause gastrointestinal disease are in this category. Several human gastrointestinal pathogens produce toxins which act on the small intestine, causing secretion of fluid which results in diarrhea. In severe cases, such as cholera, the afflicted person may die from loss of body fluids and severe dehydration. Cells of the pathogen are shed in the feces, and if these cells contaminate food or water which is then consumed by another person, the disease spreads.

It is not unusual to find some fecal indicator bacteria and even some pathogens in natural environments. The organism called Giardia lamblia (a protozoan) is an example. This organism is found in the gastrointestinal system of some wild mammals, and may enter water through the feces of these mammals. The organism causes severe diarrhea in humans. Persons who backpack or hike in wilderness areas are advised to treat all water before drinking, even if it comes from a pristine, clear, cold mountain stream. Therefore, the risk of disease is not uniquely a result of the presence of human wastes in the environment.

Nevertheless, in natural environments, organisms are relatively dispersed, therefore wastes are also relatively dispersed. In addition, natural wastes are composed of compounds natural to that environment and microorganisms in the soil and water can degrade those wastes and recycle them into usable forms. When the quantity or type of waste exceeds the capacity of the microorganisms in soil and water to degrade it, we call the waste pollution. The degradation capacity of microorganisms in soil and water is challenged by extreme amounts of wastes, as well as by unusual (often man- made) or toxic compounds. It is difficult to live in an industrialized and urbanized world and not produce localized concentrations of wastes. When human fecal wastes are concentrated in the environment, we assume, for our own protection, that the risk of transmission of pathogens may increase, even though we may have no direct evidence of the presence of a specific pathogen. It is for this reason that we monitor the quality of our food and water, and establish personal hygiene and public policies that attempt to prevent contamination in the first place.

An early study (Burm, R.J. and R.D. Vaughan, 1966, Journal of the Water Pollution Control Federation, Vol. 38, pp. 400-409) compared the bacteriological quality of the separate stormwater distribution of the city of Ann Arbor, MI with that of the combined sewer system (specifically Conner Creek drain) of Detroit. Samples were taken over several months. In April, fecal coliform counts were 10,000 per 100 mL in the separate system (Ann Arbor) but 890,000 per 100 mL for the Detroit combined system. By comparison, in August, counts were 350,000 fecal coliforms per 100 mL at the Ann Arbor site, and 4,400,000 per 100 mL at the Detroit site. Fecal streptococci numbers were more similar between the two sites.

The U. S. Geological Survey has conducted several recent studies of fecal indicator bacteria in recreational waters in Ohio, in cooperation with a variety of Ohio State agencies including the City of Columbus Division of Sewerage and Drainage, the City of Akron Public Utilities Bureau, the Summit County Department of Environmental Services, the Ohio Water Development Authority, the Ohio River Valley Water Sanitation Commission, the Northeast Ohio Regional Sewer District and the Cuyahoga River Community Planning Organization. These studies have provided data on fecal indicator bacteria concentrations in selected rivers with respect to concentration, relationship to recreational water-quality standards, and influence of environmental factors such as rainfall, runoff, and wastewater chlorination and dechlorination practices. These studies have determined that fecal indicator concentrations may be highly variable along urban rivers (for example, fecal coliform counts ranged from 20 colonies per 100 mL to 2,000,000 colonies per 100 mL for different sites and sampling dates on the Scioto River in Columbus Ohio), and may exceed recreational water quality criteria even in the absence of significant rainfall. In Ohio rivers, fecal coliform densities and densities of E. coli were highly correlated. Current studies involve the suspension of test bacteria in enclosed but permeable chambers at various sites to determine the influence of treatment practices and environmental factors on their survival. These studies should provide more information on why fecal indicator counts are so variable, and what factors influence this variability.

The U. S. Geological Survey has also collected and published water quality data for the Clinton River at Mt. Clemens since 1975. Both fecal coliform and fecal streptococci numbers were determined on a monthly or quarterly basis, along with data on the chemical quality of the water. As with the Ohio studies, densities varied greatly from one sampling time to another. These data are currently being analyzed to determine if any water chemistry variables may help to explain the bacterial densities.

USGS Contact:

Sheridan Haack- Project Coordinator
US Geological Survey
6520 Mercantile Way, Suite 5
Lansing, MI, 48911
Phone: 517-887-8909
E-Mail: [email protected]

U.S. Department of the Interior, U.S. Geological Survey
Water Resources Division, Michigan District
Maintainer: Webmaster ([email protected])
Last Modified: Wednesday, 04-Jan-2017 10:04:33 EST
Privacy Statement || Disclaimer || FOIA || Accessibility
URL Address: http://mi.water.usgs.gov/BactHOWeb.html


2.2 Analysis of Water Quality

The use of flow cytometry has to date also occurred in tandem with heterotrophic plate count (HPC) for the rapid detection of the bacterial count of potable as well as raw water (Hoefel, et al., 2005). The results showed that FCM was much quicker than HCP, in detecting viable bacteria in samples that were classed as viable but not amenable to culture. The FCM method detected bacteria within an hour as opposed to several days, for the HCP technique.

Studies have tested the sensitivity of FC-based assays in comparison to the plaque assay method, to measure levels of an infection virus in a sample (Cantera, et al., 2010). Poliovirus infection (PV1) was tested and the FCM method applied to a water sample infected with PV1-infected cells. The study revealed that a combination of flow cytometry, used with fluorescence resonance energy transfer technology, is able to sensitively and quickly detect the presence of infectious virus in a sample of environmental water.


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Fecal Indicator Bacteria and Sanitary Water Quality

Naturally some microorganisms have learned to live on or in the human body. Many of these microorganisms do no harm, and are even beneficial because they compete with other microorganisms that might cause disease if they could become established in or on our bodies. The fecal indicator bacteria are such microorganisms they are normal inhabitants of the gastrointestinal tract of humans and many other warm-blooded animals and in general, they cause no harm.

A few microorganisms (called pathogens) can cause disease in humans. In order to cause disease, a pathogen must successfully invade some part of the body and either produce more of itself or produce a chemical (usually called a toxin) which interferes with normal body processes. Whether or not a pathogen is successful in causing disease is related to the health of the individual and the state of his or her immune system, as well as to the number of pathogen cells required to make the person ill. Some pathogens can cause disease when only a few cells are present. In other cases, many cells are required to make a person ill. Children and elderly persons are more susceptible to many pathogens than are young or middle-aged adults.

Some pathogens live out their lives in the soil and water and only cause disease under unusual circumstances. The microorganism that causes tetanus is an example. This microorganism (a bacterium named Clostridium tetani) lives normally in the soil. Clostridium tetani grows in the body only in deep puncture wounds where air cannot penetrate (termed anaerobic). In this environment it produces a toxin which spreads throughout the body and may cause paralysis. Other pathogens are more closely associated with humans and other warm-blooded animals. These pathogens are transmitted from one organism to another by direct contact, or by contamination of food or water. Many of the pathogens which cause gastrointestinal disease are in this category. Several human gastrointestinal pathogens produce toxins which act on the small intestine, causing secretion of fluid which results in diarrhea. In severe cases, such as cholera, the afflicted person may die from loss of body fluids and severe dehydration. Cells of the pathogen are shed in the feces, and if these cells contaminate food or water which is then consumed by another person, the disease spreads.

It is not unusual to find some fecal indicator bacteria and even some pathogens in natural environments. The organism called Giardia lamblia (a protozoan) is an example. This organism is found in the gastrointestinal system of some wild mammals, and may enter water through the feces of these mammals. The organism causes severe diarrhea in humans. Persons who backpack or hike in wilderness areas are advised to treat all water before drinking, even if it comes from a pristine, clear, cold mountain stream. Therefore, the risk of disease is not uniquely a result of the presence of human wastes in the environment.

Nevertheless, in natural environments, organisms are relatively dispersed, therefore wastes are also relatively dispersed. In addition, natural wastes are composed of compounds natural to that environment and microorganisms in the soil and water can degrade those wastes and recycle them into usable forms. When the quantity or type of waste exceeds the capacity of the microorganisms in soil and water to degrade it, we call the waste pollution. The degradation capacity of microorganisms in soil and water is challenged by extreme amounts of wastes, as well as by unusual (often man- made) or toxic compounds. It is difficult to live in an industrialized and urbanized world and not produce localized concentrations of wastes. When human fecal wastes are concentrated in the environment, we assume, for our own protection, that the risk of transmission of pathogens may increase, even though we may have no direct evidence of the presence of a specific pathogen. It is for this reason that we monitor the quality of our food and water, and establish personal hygiene and public policies that attempt to prevent contamination in the first place.

An early study (Burm, R.J. and R.D. Vaughan, 1966, Journal of the Water Pollution Control Federation, Vol. 38, pp. 400-409) compared the bacteriological quality of the separate stormwater distribution of the city of Ann Arbor, MI with that of the combined sewer system (specifically Conner Creek drain) of Detroit. Samples were taken over several months. In April, fecal coliform counts were 10,000 per 100 mL in the separate system (Ann Arbor) but 890,000 per 100 mL for the Detroit combined system. By comparison, in August, counts were 350,000 fecal coliforms per 100 mL at the Ann Arbor site, and 4,400,000 per 100 mL at the Detroit site. Fecal streptococci numbers were more similar between the two sites.

The U. S. Geological Survey has conducted several recent studies of fecal indicator bacteria in recreational waters in Ohio, in cooperation with a variety of Ohio State agencies including the City of Columbus Division of Sewerage and Drainage, the City of Akron Public Utilities Bureau, the Summit County Department of Environmental Services, the Ohio Water Development Authority, the Ohio River Valley Water Sanitation Commission, the Northeast Ohio Regional Sewer District and the Cuyahoga River Community Planning Organization. These studies have provided data on fecal indicator bacteria concentrations in selected rivers with respect to concentration, relationship to recreational water-quality standards, and influence of environmental factors such as rainfall, runoff, and wastewater chlorination and dechlorination practices. These studies have determined that fecal indicator concentrations may be highly variable along urban rivers (for example, fecal coliform counts ranged from 20 colonies per 100 mL to 2,000,000 colonies per 100 mL for different sites and sampling dates on the Scioto River in Columbus Ohio), and may exceed recreational water quality criteria even in the absence of significant rainfall. In Ohio rivers, fecal coliform densities and densities of E. coli were highly correlated. Current studies involve the suspension of test bacteria in enclosed but permeable chambers at various sites to determine the influence of treatment practices and environmental factors on their survival. These studies should provide more information on why fecal indicator counts are so variable, and what factors influence this variability.

The U. S. Geological Survey has also collected and published water quality data for the Clinton River at Mt. Clemens since 1975. Both fecal coliform and fecal streptococci numbers were determined on a monthly or quarterly basis, along with data on the chemical quality of the water. As with the Ohio studies, densities varied greatly from one sampling time to another. These data are currently being analyzed to determine if any water chemistry variables may help to explain the bacterial densities.

USGS Contact:

Sheridan Haack- Project Coordinator
US Geological Survey
6520 Mercantile Way, Suite 5
Lansing, MI, 48911
Phone: 517-887-8909
E-Mail: [email protected]

U.S. Department of the Interior, U.S. Geological Survey
Water Resources Division, Michigan District
Maintainer: Webmaster ([email protected])
Last Modified: Wednesday, 04-Jan-2017 10:04:33 EST
Privacy Statement || Disclaimer || FOIA || Accessibility
URL Address: http://mi.water.usgs.gov/BactHOWeb.html


We manufacture an ozone based air and water purification system. We need to determine the concentration of any bacteria that remain after the purification process. We have been using a luminometer to determine the bacterial count, and verify the effectiveness of our system on solid surfaces, as well as in water. However, it is very difficult to determine the concentration of bacteria present in the air.

I agree with the answer you received from that “other” PID manufacturer. Direct reading instruments can be used to measure by-products of microbial respiration, but it takes a lot of microbes to produce a meaningful change in concentration. In order to produce contaminants microbes have to be actively metabolizing. Most of the bacteria present in the air are in the form of dormant spores, and are not actively respiring. Spores are smaller, lighter, and remain suspended in the air for a much longer period. You can easily culture any viable spores that remain after sterilization, but measuring atmospheric contaminants produced by the microbes while they are still in the air is next to impossible. Even when they are present on solid surfaces or in water, the bacteria have to be actively respiring in order to produce detectable metabolic by-products.

In a confined space, where there is no mixing with fresh air, microbial decomposition can easily create hazardous atmospheric conditions.

There are many different types of bacteria and microbes involved in this process. Some types of “aerobic” microbes use oxygen, and produce carbon dioxide. Other types of “anaerobic” bacteria that do not use oxygen produce methane and hydrogen sulfide. Which types of bacteria are active at any moment depends on the type of organic material that is present in the confined space, the oxygen concentration in the space at that time, and other environmental conditions such as humidity and temperature.

The effects of microbial decomposition on the atmosphere in the space often (but not always) follow the same sequence. Aerobic respiration, which utilizes oxygen, is the most efficient way to convert organic material into energy. That’s why human beings are aerobic organisms that require oxygen. When not actively metabolizing, bacteria and microbes are present in the form of dormant spores. The still atmosphere in a confined space initially contains plenty of oxygen. These early conditions are good for aerobic decomposition. Oxygen using bacteria and microbes become active, and begin to proliferate. Aerobic bacteria deplete the oxygen, and generate CO2. Being much heavier than fresh air, the CO2 tends to accumulate in the bottom of the space, creating locally anaerobic conditions. Anaerobic bacteria remain in the form of inactive spores until conditions become agreeable for their metabolism. As the atmosphere becomes increasingly oxygen deficient, anaerobic microbes germinate and begin to metabolize.

Anaerobic microbes do not require oxygen. Anaerobic decomposition is less efficient, and proceeds more slowly than aerobic decomposition. The metabolic byproducts of anaerobic respiration include methane (CH4) and hydrogen sulfide (if the organic material in the space includes sulfur). The more sulfur the organic material in the space contains, the greater the concentration of H2S that is likely to be produced by anaerobic bacterial action. Being heavier than air, the H2S also tends to accumulate near the bottom of the space. Methane, being lighter than air, tends to rise, and accumulates near the top of the space, or escapes from the space, if there are any openings.

I would suggest continuing to assess the bacterial count on solid surfaces and in the water by means of the luminometer. Unless you leave the sterilized area alone for a lengthy period of time, you are unlikely to see anything going on in the air, even if the purified armosphere includes viable spores. The spores have to germinate to have an effect on the atmosphere.

On the other hand, a prime application for the G450 and G460 is to monitor the atmosphere where microbial action can cause dangerous conditions. Anaerobic fermentation is used to produce alcohol, wine, distilled spirits and beer. It is highly associated with the presence of dangerous levels of CO2, as well as oxygen deficiency. Hydrogen sulfide is highly associated with sewage and wastewater treatment, oil production and refining, commercial fish and meat processing, and many other industrial applications. Methane produced by microbial action is highly associated with many types of confined spaces, including sewers, manholes, digesters, vaults and tunnels.

So, while a few dormant spores may not cause a measurable change in the atmosphere, large numbers of actively metabolizing bacteria can rapidly produce deadly conditions!


Water monitoring device will provide fast diagnosis of deadly bacteria

Credit: Africa Studio, Shutterstock

A novel microbial detection module will help water distribution networks speed up the process of contamination measuring. This will lead to significant savings with real-time critical data.

Waterborne infectious diseases constitute a major burden on human health. Contaminated water can lead to outbreaks of diarrhoea, cholera, dysentery, typhoid and polio. Such drinking water is estimated to cause 502 000 diarrhoeal deaths each year, according to the World Health Organization. That's why ensuring the microbiological safety of water is crucial.

A team of researchers backed by the EU-funded WaterSpy project is developing a device for pervasive and online monitoring of tap water. It's a portable laser-based water quality analyser that can be utilised at critical points on water distribution networks. It can provide a safety reading in a few hours rather than days, helping water utilities, public authorities and regulators save time and resources. The prototype is ready and the team will test it in two sites in Genova, at the Prato Water treatment plant and the entry point of the Genova water distribution network.

WaterSpy will focus on monitoring three of the most deadly bacteria strains: Escherichia coli, Salmonella and Pseudomonas aeruginosa. As explained in a press release on the project website, these bacteria are often hard to detect as the concentration of contaminants can be low. "The current process involves water samples being taken and sent to a remote laboratory, and with bacteria traces often so small, a period of 24 hours is needed to allow the pathogens to cultivate." As a result, a full analysis could take up to 2-3 days. However, the research team hopes to get results in just 6 hours, about 12 times faster than the current standard.

Combining light and sound

WaterSpy relies on a laser configuration, photodetectors and ultrasound particle manipulation. The same press release explains: "It works by first gathering small traces of bacteria and then detecting them with a laser." Ultrasound is used to congregate the bacteria in the water sample in order to enhance the detection and sensitivity. A measurement technique called attenuated total reflection will be used, enabling a sample to be examined directly in the liquid state. "Beams of infrared (IR) light are sent into a diamond over which the water flows. The IR light then reflects off the internal surface in contact with the water sample, before being collected by a detector as it exits the crystal."

The ongoing WaterSpy (High sensitivity, portable photonic device for pervasive water quality analysis) project was set up to develop water quality analysis photonics technology suitable for online field measurements. For validation purposes, WaterSpy technology will be integrated into an existing commercial water quality monitoring platform in the form of a portable add-on. According to the team, WaterSpy technology is relatively cheap and will comply with strict requirements in terms of specificity and sensitivity levels in the wake of new drinking water regulations.