Projects
Treatment Plant, Preston Deanery, Case Study
We were approached by a domestic customer in Preston Deanery, Northants, They had an old septic tank, and this was preventing them from selling their house, as septic tanks are no longer compliant in most cases.
Objective
Our objective was to install a new septic tank, including electrical connection. Then to lay pipework to a live watercourse, and to switch the old foul system over to the new Treatment Plant.
About the project
Having been instructed by our customer, we got to work in getting a Section 106 approval for the connection. We got this approval back from Anglian Water within 3 weeks. We then made contact with Highways, who weren’t so forthcoming unfortunately. There were many conversations back and forth regarding whether or not the road should be closed. Eventually, we proposed ourselves that the road be closed – the excavation was to be 4m deep and would take up half the road, but this excavation would also extend into the footpath. As there was no footpath on the other side of the road, there would be nowhere for the pedestrians to go whilst the work was being carried out.
We did a site survey first, to ascertain levels, including levels of the existing foul system and septic tank, and how it would work with the inlet level on a new Treatment Plant. We also had to factor in the level of the watercourse (the stream) relative to the outlet on a new Treatment Plant. The house had 6 bedrooms, so would ordinarily need an ‘8-person’ Treatment Plant. However, the property had he potential to add more rooms and bedrooms, and was soon to be sold, so we opted for a 10-person plant to allow for extra future capacity. The levels didn’t work very well with the stream – the outlet level on the plant was about the same height as the level of the stream in summertime. With the level of the stream likely to be much higher during wetter months, this would put the outlet of the plant below the level of the stream, which would have the effect of flooding the plant. A one-way non-return valve would be solution to prevent the plant from being flooded, but still, the effluent from the plant would not be able to discharge for many months of the year.
We therefore opted for a ‘pumped outlet’ whereby the effluent is pumped uphill and then discharges into the stream at the very top, and away from the level of the stream down below.
We started the work in September, but the weather wasn’t great, so we brought track mats to site, to move the plant about the garden without causing too much damage to the grass. We excavated for the Treatment Plant first, and installed it on a concrete slab, with full concrete surround. The plant was installed in order that the inlet was low enough for the existing foul drainage system to be able to discharge into it. This put the plant about 250mm below the existing grass, so we needed a riser fitting to the plant, which was supplied to us by the manufacturer, Marsh Industries. We’ve been working with Marsh for nearly 20 years and always install their Treatment Plants, which are made to order.
With the plant installed, we excavated for and lay the outlet pipe, this was a black 32mm MDPE pipe. This was laid to within 3m of the stream, and then put into a 110mm underground drainage pipe. The pipe was surrounded with ‘fill’ sand, and warning tape laid above, and then the trench backfilled and the grass reinstated.
We then excavated for the electric feed to the plant, this was laid in a black 63mm duct. The electric feed was taken from one of the outhouses, with an isolator fitted, as per Building Regs. We instructed an electrician, who connected up by the ‘blower’ which blows oxygen into the plant, and also the pump which pumps the effluent out to the stream, when the effluent in the plant gets to a certain level.
We then excavated for and made the switchover from the old system to the new system, which included fitting a new manhole where the old pipework met our new pipework. All systems were tested, and the remainder of the garden and gravel driveway reinstated.
The work took a bit more than a week, and as with an install of any Treatment Plant, it’s good to see a satisfied customer, and no longer with the worry of a non-compliant septic tank.
Our customer was kind enough to leave us a 5-star review on Google afterwards:
“First class service from start to finish executived by first class team who overcame unexpected difficulties with humour and no added costs. John Clark runs an excellent operation and we would recommend him highly.” Click here to see our Google reviews
Timeline
Time taken to quote for the works: Less than 1 week
Our leadtime to carry out the works: 6 weeks
Time taken for Treatment Plant to be manufactured: 6 days
Time taken to do the work: 6 days
Unfortunately it took over two weeks for the customer to obtain the full Building Control approval certificate. Whilst this is usual, it did hold up the sale of the property.
If you need a Treatment Plant installling and the project is part of selling a property, be sure to contact us with as much notice as possible.