RA Dalton Success Stories

Here at R A Dalton, our works remit can vary greatly and we rely on the versatility of our installation teams to adapt to the requirements of each job. Over the past few weeks one of our installation teams have been working at a site in Chester doing the final phase of a connection to mains sewer project. Prior to this they had been on a monumental Sewage treatment plant installation in the Lake district that lasted from November 2019 to March 2020 and before that they were installing a small Klargester Bioficient in Yorkshire.

One of the less common scopes of our work is connection to mains sewer, we have previously done quite a few connections across the UK ranging from new housing estates, Pub/ restaurants and now a new forestry cabin development.

Each site had very different requirements and this site in Chester has got to be one of our biggest connection projects to date!

For this site in particular, the process has been extensive and thorough with every option considered. After thorough evaluation of the site it was deemed that the most practical route was to install 2 no. package pump stations to pump to mains sewer.

Working closely with Klargester we then drew together the specification for the pump station(s), the specification for the site identified that there needed to be enough capacity to suit 67 cabins (171 bedrooms) and a restaurant (estimated at 80 daily covers) along with the distance required to be pumped.

Prior to any installation works starting on site there were a number of elements that needed to be considered, this included with licenses required, areas for construction and possible solutions to any issues that arose.

It was identified early on in the construction phase that there was a gas pipeline in the working area that would need to be avoided at all costs, with no data stored for the depth of which this was installed we went to site in May 2019 to carry out some trial digs. Using a machine with toothless buckets and a lot of hand work we carried out a number of test excavations and the depth of the pipe was identified to run from 610mm to 810mm in our working area.

Working alongside the gas authority the run of the old gas pipe was marked out with depths noted for when the main phase of works began.

For the connection to mains sewer there were a few licenses our office team were required to acquire, the first of which is the section 106 which allows for the connection of the foul waste from the site to mains sewer. Each water authority has their own 106 license form to connect to mains sewer, within this they ask for details on estimated flow and proposed connection point.

The Section 50 is the main license that allows us to work in the road, subsequently our installation team hold both the street works certification along with confined space should the manhole deep enough to require this.

By October 2019 we were ready to start the initial pump station installations, there were two different pump stations on site, the PU2640TS and the PU2645TS. The larger pump station handled both the flow from the smaller system and the gravity flow from the localised facilities and pumped to the mains sewer.

The pumps were not only designed to handle the flow but also the considerable distance to travel before the final connection point. This job included over 1750m of rising main before connecting to the mains sewer.

Due to ground conditions not being the best we had to install the package treatment plant using temporary shoring equipment and a Hydrainer pump to limit the groundwater coming in to the excavation. With the wet dig it was vital that we used the right specification of concrete to ensure the system did pop out of the ground.

Within our proposal we offered two options for the customer, the first of which was to limit disruption and reinstatement in the roadway and using directional drilling along the main roads (up to 940m distance on the two roads) then to open excavate along the private roads (approx. 800m) or to open excavate the full amount.

Ultimately the first option was the most practical and eco-friendly choice as it meant limited excavation in the road and could be achieved at a much quicker rate with only small sections of tarmac reinstatement being needed.

Choosing the first option was the most logical to get the works carried out within the time frame and limited the amount of time the engineers were on the main road. Traffic management was in place for the duration of the pipework installation inclusive of the actual connection to mains sewer and after 3 and half weeks of graft that element of the works were complete.

Our installation team are now working swiftly through the open excavation of the works working back towards the pump station we had installed back in October this year.