Marsh Industries are a large UK based sewage treatment manufacturer, they offer a basic sewage treatment system, type tested under EN12566-3 and approved for installation in the UK.
The Marsh Ensign treatment plant is type tested under EN12566/3. The tank is made in 2 halves from GRP (glass reinforced plastic) and bolted together with a waterproof sealant. It uses a constantly aerating method to provide oxygen to bacteria living on the filter material within the system.
With a range from 4 persons to 50 persons, Marsh are one of the only companies that offer a 4 person treatment plant. Which is ideal for a small office, however unsuitable for a household.