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In October 2021 our contracts Manager Ian Murray attended a property in County Durham who were requiring their existing non-compliant septic tank to be replaced with an appropriate package sewage treatment plant.  The old unit was discharging the untreated effluent into the beck adjacent the property.

The new plant was to be installed in the same location but due to the topography of the ground and the discharge location a pumped system was to be utilised. The outfall pipework was to be installed at the higher level to account for the beck being at high level.

Owing to the fact the system was to be situated in close proximity to the access lane we proposed to install the new system with a B125 vehicle duty cover and frame. This is where the Bioficient was the ideal system to install, the tank access covers were easily replaced with the heavier duty alternative.

With limited space on site we opted to install the new treatment plant within the walls of the existing concrete/ brick construction – whilst this used more concrete than usual it did remove a larger requirement for removal of spoil should a fresh excavation be required.

This system is easily one of our installation team’s favourites to install, the design of the Bioficient 1 is suitable for shallow dig requirements and the robust yet light weight system makes for an easier and more affordable installation.

Despite the compact design the system comprises of three treatment zones, the following is taken from the Klargester Brochure to explain each section of the treatment process:

1. The Primary Settlement zone – Raw sewage gravitates to the unit where it is received in the primary settlement zone. Here, gross solids and other social debris settle to the bottom of the tank where they remain until the tank requires desludging. Settled sewage is displaced from primary zone and enters the first of two sequential moving aerated media reactors.
2. The Biozones – “Solids are broken down by air agitated media in the Biozone. Media and liquid circulation in the Biozone is achieved through the use of a compressor and diffuser, which introduces fresh air into each compartment. The liquor is constantly re-circulated and contacts the moving media and as it does so, it is purified by the microorganisms growing on the surface of the media and within the moving liquor. Excess growth of biomass is shed as solid particles into the liquor.”
3. Final Settlement tank and sludge return unit – “The final settlement tank is where humus solids settle to form sludge. At preset intervals, portions of the sludge and liquor are returned to the primary tank for additional treatment.”

One of the most vital things to remember when you have a sewage treatment plant installed is that the maintenance isn’t covered by servicing the system alone, routine checks should be carried out by the proprietor of the property to ensure that the system is fully operational, this can usually be done by just listening to check you can hear the blower or the discs turning.

There are number of reasons we advise this is done, especially in the case of an IPS (pumped) unit. Should the pump fail in the treatment plant this will mean that the system if no longer allowing the treated effluent to flow away. It will only be a matter of time before the system then starts backing up the inlet drains as the outlet has nowhere to go!

Equally if the blower is not working or if the discs aren’t turning this means that your treatment plant is not operational, there will be limited to no treatment taking place. This is on a par with having a septic tank installed and subsequently you will be temporarily classed as non-compliant until your system is operational again.