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5 Things You Need to Know About the OdaLog

OdaLog Gas Datalogger

Hydrogen Sulphide (H2S) is a detectable gas in low concentrations and is a major problem in sewers. H2S attacks concrete and mortar above the liquid level in pipes and chambers causing it to corrode and deteriorate.

And then there’s the smell! Most people liken H2S to that of rotten eggs. For neighbours of wastewater treatment plants, nuisance smells are a common occurrence. It’s in their best interests that the odours are controlled.

Anywhere that currently has or potentially has an odour or corrosion problem, an odour control program should be in place to identify the severity of the problem. Such a program should involve careful evaluation of the data obtained from sample collection and analysis.

The OdaLog

Designed for logging data in the wastewater sector

The OdaLog - a datalogger specifically designed for the wastewater Industry is used primarily for locating at or close to the source of H2S gas emissions such as within sewerage pumping stations and manholes. It has been designed to help drainage authorities, water companies and environmental regulators reduce the costs of monitoring and also improve timely on-line access to high quality measurements at remote sites.

Which applications benefit from the OdaLog?

Odour abatement

Odour abatement management and control takes place at wastewater and sewage treatment works where they process sludge and wastewater. This is an extremely sceptic process and odours must be controlled by a combination of liquid dosing and dry scrubbing technologies.

Liquid dosing is intended to reduce the sulphide levels to an acceptable level prior to the dry scrubbing system, so that the final scrubbing leaves a gas stream in a non-noxious state.

The OdaLog can be integrated into a dosing system within the sewer network to log levels of Hydrogen Sulphide (H2S). Dosing chemicals can be controlled whether to increase or decrease in reaction to the H2S levels. This provides a fully automated odour abatement chemical dosing system.

Indoor air quality

In poultry farming where thousands of birds are kept in large sheds, long-term monitoring for Ammonia (NH3) or Hydrogen sulphide (H2S) is required to control the environment. The OdaLog is ideal as a cost-effective long term monitoring device in these conditions with a battery life of around one year.

Area Monitoring

The OdaLog has been used as an area monitor in applications where long-term monitoring is required for research purposes. The OdaLog is ATEX approved so it can be used in intrinsically safe zones.

Datalogging and Reporting

OdaStat-G can interface with a PC through an IrDA or internet connection. The software allows data to be presented in tabular or graphical form to highlight significant variations in H2S levels over time. OdaStat-G needs to be purchased with an OdaLog if not already previously owned


The OdaTrak™ 4 to 20mA adapter reads gas concentration data sent from an OdaLog® gas logger over a fibre optic cable. This then deciphers the data, and then outputs the corresponding 4-20mA loop analogue signal. This allows the OdaLog® unit to be interfaced to control and telemetry systems providing real-time gas data.

This signal could be used to optimise chemical dosing, trigger alarms, control ventilation fans, or interface to telemetry systems etc.


Standard Life OdaLog models should be deployed no longer than 1 week at a time.

The long life sensor has a small aperture which absorbs moisture at a slower rate compared to the standard sensor. This means that the long life sensor can be deployed for up to 4 times as long as the standard life sensor.

Sensor Recovery Time

Whilst the OdaLog has been designed for use in a wet, toxic and humid environment, the OdaLog's gas sensors will require recovery time in what we call 'office' conditions (dry, air conditioned). The OdaLog Dry Dock can reduce recovery time by half.

Standard Life OdaLog models require 1 week in ‘office’ conditions or just 3.5 days recovery on the Dry Dock.

Long Life OdaLog models require 4 weeks’ recovery time or just 2 weeks’ recovery on the Dry Dock.

For More Information, Visit our OdaLog Page