MS2000 - On-line THM Monitor

No Reagents, Low Maintenance, Hourly readings

Detects Total Trihalomethanes in drinking water

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THM Analyser and Monitor
MS2000 - THM Monitor

The MS2000 is a Total Trihalomethane on-line monitor which provides measurements of THMs at low concentrations in water.

Regulations limiting the levels of Disinfection By-Products (DBPs) such as Trihalomenthanes (THMs) in drinking water have made the ability to measure DBP levels throughout the distribution network essential. Multisensor’s THM monitor provides that facility, efficiently and accurately.

Measuring Total THMs with a high accuracy, the MS2000 provides the confidence that is needed in a process control instrument which is vital in meeting regulatory and legal requirements. It is designed to:

  • Analyse THMs post treatment
  • Monitor THMs in the distribution network
  • Monitor THMs post-chlorination for enhanced process control
  • Calculate THM Formation Potential (Optional)

Features and Benefits

  • No sensor contact with water: low maintenance, no sensor cleaning
  • NO REAGENTS: low running costs
  • The most cost effective solution
  • High sensitivity: ideal for potable water
  • Alarms to SCADA and other communication interfaces

For more information on the principle of operation, click on the FAQs tab.

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THMs and the risks to health

Tap Water should not contain high levels of THMs

Trihalomethanes (THM) are a group of four chemicals that are formed along with other disinfection by products when chlorine or other disinfectants used to control microbial contaminants in drinking water react with naturally occurring organic and inorganic matter in water.

The THMs are Chloroform (CHCl3), Bromodichloromethane (CHCl2Br), Dibromochloromethane (CHClBr2), and Bromoform (CHBR3). National regulatory bodies set limits for the level of THMs in drinking water which, in most countries, are tested on a regular basis at the customer’s tap.

They are Cancer Group B carcinogens (shown to cause cancer in laboratory animals). Chloroform is by far the most common in most water systems. Dibromochloromethane is the most serious cancer risk, (0.6 µg/l to cause a 10-6 cancer risk increase) followed in order by Bromoform (4 µg/l), and Chloroform (6 µg/l).

THM levels tend to increase with pH, temperature, time, and the level of "precursors" present. Precursors are organic material which reacts with chlorine to form THM's. One way to decrease THM's is to eliminate or reduce chlorination before the filters and to reduce precursors. There are more precursors present before filtration, so it is best to reduce or eliminate the time chlorine is in contact with this water.

The US EPA, for example, has indicated that the best available technology for THM control at treatment plants is removal of precursors through "enhanced coagulation". Enhanced coagulation refers to the process of optimizing the filtration process to maximize removal of precursors. Removal is improved by decreasing pH (to levels as low as 4 or 5), increasing the feed rate of coagulants.

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Minimum Maximum
Detection Range 5 ppb 1,000 ppb
Display Range (Default) 0 ppb 200 ppb Configurable on commissioning
Repeatability -2% +2% See Note 1
Accuracy -10% +10% See Note 1
Measurement Frequency 60 minutes Measurement reporting time 2 minutes
Ambient Temperature 0 °C 40 °C See Note 2
Water Temperature 1 °C 40 °C See Note 2
Analogue Output 4 mA 20 mA Scalable to range required, max load 900 Ω
Analogue Output Isolation 400 V DC
Relay Voltage 50 V Alarm and Fault Relays with NO and NC contacts
Relay Current 5 A
Service Interface On-screen -or USB-A to PC Not available without touchscreen
Data Storage μSD Card Instrument lifetime data stored
Instrument Case IP65 Coated Mild Steel
Instrument Weight 16 kg
Sampling Chamber Material Stainless Steel
Sampling System Weight 12 kg Without water
Sampling System Dimensions 570 x 490 mm
Sampling System Capacity 3 litres
Flow Limit Switch Contacts closed if flow below set point Option available on request
Water Flow Rate 0.5 l/min 1.0 l/min
System Dimensions 1170 x 490 x 300 mm Mounted on 2 separate PVC backboards
Supply Voltage 90 V AC 240 V AC 50 Hz or 60 Hz
Power Consumption 45 W
Typical 45 W during operation

Note 1:+/-10% from 30 to 1000 ppb, measured against a 100 ppb chloroform standard at standard temperature and pressure;Accuracy can be further improved at points of interest, using bespoke calibration. Note 2: Climate control might be needed depending on process and ambient conditions.

View Datasheet

Title Type Format
MS2000 - Total Trihalomethane (THM) Monitor Datasheet PDF
THM Monitor in Drinking Water Case Study PDF
Total Trihalomethane Measurement using a Reagentless and Contactless Analyser developed by Multisensor Systems Ltd. Article PDF
How does the Total THM Monitor work?

The principle of operation of the MS2000 THM Monitor is the measurement of headspace gases from a sample tank containing the water to be measured.

Through the use of Henry’s Law the concentration of gases in the headspace is proportional to the concentration of the substance in the water.

Calibration of the instrument is done by presenting a known concentration to the sensors and generating calibration coefficients from the responses obtained.

The MS2000 works by passing water through a sample tank as shown below. The volatile components in the water will pass into the headspace above the water where they will be trapped. This will continue until equilibrium is reached.

A sample of the headspace gases are then passed across sensors in the MS2000 THM Monitor sensor head, which respond to the THMs in the headspace. This response is then analysed by the instrument and a concentration value is generated based upon the relationship between the concentration present in the headspace and that in the water.

For the detailed calibration technique see MS2000 Operation and Maintenance Manual. The technique is to present standards of THMs in water to the instrument. Multisensor recommends that this process is carried out in their factory and a pre calibrated sensor head is fitted in the field.
Validation of systems in the field is achieved using the Multisensor Validation Kit which presents a standard concentration to the instrument.
What does the MS2000 THM Monitor actually measure?
The MS2000 measures the concentration of Total Trihalomethanes in water, which is given by the sum of chloroform, bromoform, Bromodichloromethane and Dibromochloromethane.
How often does the instrument provide a reading?
Compared with other on-line parameters, THMs tend to vary slowly over the course of the day. The MS2000 Total THM monitor provides a reading every hour which is far quicker than our nearest competitor (once every 4 hours)
What is the reported value?
The instrument will report the Total THMs value.
How is the MS2000 calibrated?
The instrument is factory calibrated against a chloroform standard. Other requests can be considered
What is the required maintenance? Is it expensive?
The instrument requires a service every 6 months which include a sensor replacement as part of the low cost service pack. This is part of a sensor replacement scheme which can be discussed with Multisensor or your distributor.
What is the warranty?
Every instrument comes with 1 year warranty from the shipment date
What are the advantages of using e-nose technology?
E-nose technology allows for non-contact measurement meaning that:
  • fouling of the sampling system is minimized through large diameter tubes being used
  • suspended solids and dissolved chemical compounds do not coat or damage the sensors or optical components as used in Ultra Violet, Infra Red or Laser spectroscopy systems, extending their lifetime and reducing cleaning requirements
  • no reagents are necessary as for instruments which use colorimetry as their detection technology
  • no purging gases are needed as for GCMS based systems
How much water does the MS2000 use?
The MS2000 uses up to 1 litre per minute, which is simple to dispose of, but since no reagents are used the water could be returned to the water supply.
Is the MS2000 sensitive to environmental conditions?
The MS2000 employs temperature and humidity control and compensation techniques to remove the effects of these parameters. Some volatile chemicals can be an interferer, but if these were found in any concentration in drinking water, where the MS2000 would be employed, they would represent a serious health risk in themselves.
What are the System and Monitoring Options
The MS2000 is packaged in a small enclosure and requires no additional chemical reagents for operation. The system includes both the measurement instrument and the sample presentation system, to allow the simple fitting of the unit within existing facilities.
A variety of communications options can be provided including 4-20mA loop, Wireless, Modbus and Profibus. The sensors can detect Total Trihalomethanes, or TTHMs including Chloroform, Bromoform, Bromodichloromethane and Dibromochloromethane.
For more information, please download the MS2000 Total Trihalomethane Analyzer Datasheet.

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Case Studies and Articles

The THM monitor has been used in numerous applications. We are now working to bring these case studies to you.

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