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Measuring methane


At the UK’s first viable compact anaerobic digester (AD) plant aimed at local food waste treatment, a Geotech GA3000 fixed biogas analyser monitors methane (CH4), carbon dioxide (CO2), oxygen (O2) and hydrogen sulphide (H2S). The plant, a modular scalable AD system, unveiled by React Environmental in July 2012 at Llangadog, Carmarthenshire, can handle some 1,000 to 5,000 tonnes of food waste a year.

Commenting on the Geotech biogas analyser, React’s Arrash Shirani said:

It has also been very useful for determining the health of the system and showing us how effective different system configurations are e.g. different digester operating temperatures.We built the plant as a prototype and demonstration unit so we needed to monitor the process carefully and be able to show potential clients how effectively it is working.

Perfect fit
The GA3000 biogas monitoring system is designed to help optimise AD production and provide combined heat and power (CHP) engine protection and restart. This makes it very well matched equipment for biogas plants and landfill sites generating electrical power. Although an ‘entry level’ automatic fixed position biogas analyser, the GA3000 provides full round-the-clock analysis. A 4-20mA output for each gas is standard, as is Modbus digital output, allowing communication with SCADA systems. Alarm relays are user configurable and it is ATEX Zone 2 certified.

Patented process
React’s anaerobic digestion plant incorporates a patented separated hydrolysis system that converts organic material into renewable energy. This is a subtle but important evolution in the principal biological process common to anaerobic digestion plants. Developed in Britain, the process has already been licensed to plants in Europe. The process and monitoring systems enable maximum constant yields of biogas to be maintained, delivering increased efficiency – typically up to 30% better than existing methods – with less operator supervision required.

The system is scalable and straightforward to install and opens a new market for local treatment plants for feedstock such as municipal household, institutional, process and commercial food wastes. Options include digestate drying and pelleting plant.

React is set to roll out the pioneering compact food waste treatment plants following extensive trials of a demonstrator in South West Wales, which is now accepting waste from Carmarthenshire Council and HRH Prince Charles’ estate in Wales.

Wales & worldwide

Geotech has more than 200 fixed biogas analysis systems in use worldwide, with applications including AD research facilities, waste water treatment, food and farm waste treatment. Vital for CHP restarting and protection against sudden gas level changes, biogas monitoring equipment can pay back in weeks or even days. Released last year, the GA3000 PLUS builds on the success of the GA3000 with multiple sample points and both high and low H2S ranges, perfect for monitoring pre and post desulphurisation or multiple digesters.

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