Wastewater Treatment Plant & Septic Tanks

Septic Tank Installation? J&F Drainage Have it Covered

When it comes to septic tank installation & wastewater treatment plants, J&F Drains are the only company to call.


Under the Environment Agency General Binding Rules, Boreholes and soakaways are not acceptable. Soakaway Creates and Tunnels are also not allowed for septic tanks or any sewage effluent, only for rainwater. All septic tanks whose effluent finds its way into ditches or streams, either directly, or by mistake, have to be replaced with sewage treatment plants.

Septic Tank Maintenance

All septic tanks require emptying once a year. They only hold 12 months’ sludge storage and if sludge starts to empty into the soakaway soil, it very quickly blocks the air spaces (porosity) in the soil, the effluent cannot soak away, you suffer a soakaway failure and the septic tank fills up, backing up the system.

Wastewater Treatment Explained

The Objectives of Sewage Treatment. Raw sewage is very polluting and all wastewater must be treated in order for it to be environmentally safe.

The three main parameters used to define sewage both as it arrives at a treatment plant (influent) and when it leaves a sewage treatment plant (effluent), are BOD, Suspended Solids and Ammoniacal Nitrogen. Sometimes, Phosphorous is also considered, particularly if the discharge is to a sensitive watercourse or lake, but this is not usually a requirement in the UK.


One of the main pollutants to consider is BOD or Biochemical Oxygen Demand.

This measures the amount of oxygen, in Mg/L, required by microorganisms in the sewage to break down its organic matter content. Sewage with a high BOD has high pollution potential if discharged into a watercourse because it causes severe depletion of the oxygen in the water. This kills fish and other aquatic animals which need this oxygen to breathe.

Normal domestic sewage generally has a BOD of between 250 and 400mg/l. This is much too high and sewage treatment must reduce it to a maximum of 20mg/L in the UK to minimize pollution potential. The Environment Agency may require sensitive sites to achieve even lower levels.

A sewage treatment plant cleans and removes contaminants from domestic sewage, using a combination of physical, chemical and biological processes. Typical applications for a water treatment plant include single dwellings, small communities or developments, refurbishments and rural barn conversions. Sewage treatment plants can be placed above or below the ground depending on the type of installation you require.

J&F drains are here to help with all your wastewater needs. Contact us today to discuss your requirements.