Installation
Sewage treatment plant installation in Suffolk
A packaged treatment plant cleans waste water well enough to discharge to a ditch or stream. On Suffolk clay, where drainage fields often struggle, it is usually the most reliable way to meet the rules.
What a treatment plant does differently
A septic tank holds sewage while the solids settle out, and the liquid flows on largely untreated. A treatment plant adds a second stage, where a small blower pumps air into the tank so bacteria can break the waste down. A final settlement chamber then lets cleaner water leave the plant.
Because of that extra treatment, a plant built to BS EN 12566-3 can discharge to surface water where a septic tank cannot.
Choosing the right plant
- Size. Plants are rated by population equivalent (PE), worked out from bedrooms. Holiday lets and annexes need extra thought.
- Ground and water table. High groundwater near rivers and the coast affects which tank shells can be used and how they are anchored.
- Where it discharges. A flowing ditch or watercourse, or a drainage field if the ground passes a percolation test.
- Power and access. The blower needs a safe supply, and the tanker needs to reach the plant for emptying.
Treatment plant questions
What size treatment plant do I need?
Plants are sized by population equivalent (PE), based on the number of bedrooms rather than how many people live there now. A typical three or four bedroom house usually needs around a 5 or 6 PE plant. We confirm the size at survey.
Can a treatment plant discharge to a ditch?
Yes, if the ditch or watercourse flows for most of the year and the plant meets the British Standard. That is the main reason treatment plants are used where ground drainage is poor.
How often does a treatment plant need emptying?
Typically about once a year, depending on the plant and how heavily it is used. The manufacturer's guidance sets the interval, and a service visit checks the blower and outflow.