When carrying out an initial site visit for a potential installation it is a priority of our contracts managers to try and cover every possible scope that may be required. Unfortunately, the installation of a new sewage treatment plant is not a straightforward and a number of factors need to be taken into consideration.

Some may think that the selection of new sewage treatment plant/ septic tank is the most important and first thing to decide however a number of variables can adapt this therefore it is vital that site is considered as a whole before the system is selected.

All new installations MUST conform to the 2020 General Binding Rules, this legislation outlines the steps a proprietor must take in order to limit any unnecessary environmental pollution. One of the first things to consider is where the discharge location is likely to be, this could be to Mains sewer, watercourse or to a drainage field.

The first step is to identify if a connection to mains sewer is feasible, if this is in relation to a single domestic property it cannot be within 30 metres of the mains sewer otherwise this would need to be the first avenue to be pursued.

If this is not an option, off-mains drainage would be the suitable solution. Regardless of the discharge location a sewage treatment plant can be utilised for both options, whereas a septic tank can only be used to discharge to ground.

One installation we recently undertaken in North Yorkshire was to find a suitable, long-term solution to the wastewater for a 4-bedroom property. With no local watercourse the outfall was to go to a drainage field located within the property boundary.

We selected the Bioficient 1 as the proposed system to install to suit this property, prior to the work on site commencing we needed to carry out percolation tests to determine the size of drainage field required.

These test determined that the substrata consisted of a deep layer of soil before grading into a sandy clay material, this gave a percolation value across the pits of 48.59. This meant that based on the British Flows and Loads Calculations we would need to install circa 65 metres of drainage field in a 900mm wide trench.

It is standard industry practise to ensure that all surface water drainage is separate from the foul network, this is a necessity as for any septic tank or sewage treatment plant to be able to function efficiently and in line with the manufacturer’s guidelines.

To appropriately calculate the population criteria for a sewage treatment plant/ septic tank this is based on the daily flow per person, the issue with rainwater connections is that this is never a regulated amount and heavy rainfall can cause the system to be overloaded, displace the settled waste, and have a detrimental effect on efficiency of the treatment process.

During our initial site attendance, we advised the customer that we would need to check whether this isn’t connected and if it this would require all roof water to be diverted to an individual rainwater soakaway.

To enable the installation to take place we required access to be made available to the working area, this meant that a section of conifer hedge needed to be removed by others prior to our start on site, this allowed for the hedge line to be reinstated once work is complete.

Despite intermittent periods of heavy rainfall, the installation went without hitch with a clear and concise scope of works. This enabled our site team to be able to keep the customer up to date as the work progressed and to explain each step of what they were doing.

The efforts of our site team did not go unnoticed and following the completion of the works and the sign off under Building control the customer reach out to us to thank them for their hard work:

“Thank you for the recent work completed at our House, your team did a great job and took time to explain the works and were professional and courteous.”