MS2000-S – Online THM Monitor

The MS2000-S is a highly sensitive online Total Trihalomethane (THM) analyser which helps water treatment operators optimise their process to meet local regulations. The MS2000-S uses a contactless measurement technique that greatly reduces maintenance requirements. Furthermore, the instrument does not require reagents, minimising ongoing running costs.

Regulations limiting the levels of Disinfection By-Products (DBPs) such as Trihalomethanes (THMs) in drinking water have made the ability to measure THM levels throughout the distribution network essential. Multisensor’s MS2000-S provides that capability efficiently and accurately.

Measuring Total THMs with high accuracy, the MS2000-S provides the confidence needed in a process control instrument, which is vital for meeting regulatory and legal requirements.

Applications

• Analyse THMs post-treatment
• Monitor THMs in the distribution network
• Monitor THMs post-chlorination for enhanced process control

Features and Benefits

• No sensor contact with water: low maintenance, no sensor cleaning
• No reagents: low running costs
• 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, see the FAQs tab.

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THMs and Health Risks

Trihalomethanes (THMs) are a group of four chemicals 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.

The THMs are Chloroform (CHCl₃), Bromodichloromethane (CHCl₂Br), Dibromochloromethane (CHClBr₂), and Bromoform (CHBr₃). National regulatory bodies set limits for THM levels in drinking water, typically monitored regularly at the tap.

They are recognised as potential carcinogens. Chloroform is the most common in most water systems, while Dibromochloromethane presents the highest cancer risk (0.6 µg/l for a 10^-6 increased risk), followed by Bromoform (4 µg/l) and Chloroform (6 µg/l).

THM levels tend to increase with pH, temperature, time, and the concentration of "precursors"—organic materials that react with chlorine to form THMs. Reducing chlorination prior to filtration and minimising precursors helps lower THM formation.

For example, the US EPA recommends removing precursors via "enhanced coagulation" as the best available technology for THM control. This involves optimising the filtration process, adjusting pH, and increasing coagulant feed rates to maximise precursor removal.

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View Datasheet

How does the Total THM Monitor work?

The principle of operation of the MS2000-S THM Monitor is based on measuring headspace gases from a sample tank containing the water to be monitored.

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

Water passes through a sample tank, where volatile components migrate into the headspace above the water until equilibrium is reached.

A sample of the headspace gases is then passed over the sensors in the MS2000-S THM Monitor sensor head. The sensors respond to the THMs in the headspace, and the instrument calculates a concentration value based on the relationship between the headspace and water concentrations.

What does the MS2000-S THM Monitor actually measure?

The MS2000-S measures the concentration of Total Trihalomethanes in water, calculated as the sum of chloroform, bromoform, bromodichloromethane, and dibromochloromethane.

How often does the instrument provide a reading?

Compared with other online parameters, THMs vary slowly over the course of a day. The MS2000-S provides readings every hour, much faster than typical competitors, which usually provide readings once every four hours.

What is the reported value?

The instrument reports the Total THMs value.

What maintenance is required? Is it expensive?

The instrument requires servicing every six months. Maintenance is minimal and cost-effective.

What is the warranty?

Every instrument comes with a one-year warranty from the date of shipment.

What are the advantages of using e-nose technology?

E-nose technology allows for non-contact measurement, meaning:

• Fouling of the sampling system is minimised through the use of large-diameter tubes.
• Suspended solids and dissolved chemicals do not coat or damage the sensors or optical components as in UV, IR, or laser spectroscopy systems, extending their lifetime and reducing cleaning requirements.
• No reagents are required, unlike instruments using colourimetric detection.
• No purging gases are needed, unlike GCMS-based systems.

How much water does the MS2000-S use?

The MS2000-S uses up to 2 litres per minute. Since no reagents are used, the water can be safely returned to the water supply.

Is the MS2000-S sensitive to environmental conditions?

The MS2000-S employs temperature and humidity compensation techniques. Some volatile chemicals may interfere, but any detected concentrations in drinking water would represent a serious health risk in themselves.

What are the system and monitoring options?

The MS2000-S is supplied in a compact enclosure and requires no additional chemical reagents for operation. It includes both the measurement instrument and the sample presentation system for simple installation within existing facilities.

Various communications options are available, including 4–20 mA loop, wireless, Modbus, and Profibus. The sensors detect Total Trihalomethanes (TTHMs), including chloroform, bromoform, bromodichloromethane, and dibromochloromethane.

For more information, please download the MS2000-S Total Trihalomethane Monitor Datasheet.

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