A Sewage Treatment Plant Installation
We were contacted by Dave and Catherine who were interested in a new sewage treatment plant installation as they had a septic tank that was not functioning well – backing up and perpetually requiring emptying. Their drainage field under the driveway had failed. The liquid discharging from septic tanks is polluting and contains suspended solids, so eventually drainage fields fail when they get filled with silt.
The Site Visit and Quotation
All our installations start with a site visit – we discuss the issues and requirements with the client and then amongst other things look at property size, options for the treatment plant, discharge points (to a watercourse or to a drainage field), electrical points, access for machinery, soil type, where the storm water goes, the general state of the sewer and manholes, etc.
The engineer then plans the project and a quotation is prepared.
For this project, the access was acceptable but it was a tight fit! The requirement was to put the tank in the corner of the drive where there was no traffic so no heavy duty covers were required. A Bio-Pure 2 sewage treatment plant for 7 people was proposed to serve the 4 bedroom property – it is a compact system perfect for the space.
In addition, at the site visit it was noted that the existing pipework was deep so the tank invert (the level where the sewer pipework enters the tank) was also going to have to be deep – the excavation was going to have to reach far down!
The design of the Bio-Pure was bespoke to the tight-fitting yet deep requirements with a specific invert requiring a neck extension and an outlet at 90 degrees which negated the need for an extra manhole. We also fitted a quiet piston compressor.
Once the quotation was signed-off, the installation date was agreed. The team in the office ordered the tank and other materials, they arranged deliveries for the machinery, gravel and cement. As the old tank was to be imploded and back-filled, an emptying tanker was also booked for a pump out. Plus, grab lorries to take away all the soil.
The installation took place in August and we were blessed with glorious weather.
Before we start any job, we complete our onsite risk assessments and scan the working area for services (gas, electricity, water). We do this with our specialist Cat-scan equipment.
The existing gravel on the drive was scraped back by our expert digger drivers – and the excavation began. Excess soil was taken by dumper to an area protected by membrane ready for collection by the grab lorry.
Some pipework went into the lawn area, so the turf was carefully lifted whilst the trenches were dug and pipework laid.
Imploding the Old Septic Tank
We will often include the empty, implode and backfill of the original septic tank in our quotations. On this occasion the new tank was to be installed in the same position. The tank was emptied by a tanker and was carefully demolished by a digger, and the new tank was installed.