Free tool to create reports after a site suitability assessment

What is the site suitability assessment?

A site suitability assessment must be performed and submitted with a planning application for both commercial and domestic applications on sites where connection to the mains is not possible. A suitable onsite wastewater treatment system e.g. septic tank or wastewater treatment plant, must be designed and implemented to treat and safely discharge the treated wastewater.

The aim of the site suitability assessment, which comprises of the Desk Study, Visual Assessment, Trial Hole Evaluation, Percolation Test and System Recommendation, is to determine what wastewater treatment systems are suitable for the site conditions.

Key elements of the site suitability assessment:

1. Desk study: a study of the soils, geology, groundwater vulnerability, presence of historical sites and local water supply schemes in the vicinity of the site.
2. Visual assessment: a site visit to assess site drainage, vegetation, topography, housing density, etc.
3. Trial hole evaluation: a trial hole is dug to check the soil depth, type of sub-soils and establish the depth of the water table in both winter and summer months. On sites with poor soil permeability, the site assessor must determine if the site is suitable for development.
4. Percolation test: also known as P/T test, the percolation test is performed to determine if the percolation rate of the wastewater through the soil has sufficient time to treat the wastewater, but also, that it percolates quickly enough through the soil to avoid ponding and a risk to surface water.
   1. Based on the trial hole evaluation, a “T” test is done to establish the percolation rate of the subsoil layer in which it is proposed to discharge to.
   2. A “P” test is performed to establish the percolation of the topsoil on sites where a mounted percolation area is proposed.
   3. The test hole dimensions and test procedures are the same for both “P” and “T” tests.
5. Recommendation: Once the site assessment has been completed, if the site is suitable for the implementation of an onsite wastewater treatment system, the site assessor provides a recommendation regarding the type of system that is suitable for the site conditions.

The results of the site suitability test are recorded in the site characterisation form which is submitted along with the relevant maps and drawings in the planning application.

Based on the recommendation in the site characterisation form, a wastewater site recommendation report should be included in the planning application which will provide the specifications and all relevant documentation regarding the proposed wastewater treatment system.

Tricel Site Assessor has been designed to assist site assessors, engineers and architects to create a comprehensive recommendation report in minutes, by providing details system specifications, drawings (both PDF and AutoCAD), brochures and service agreements.

Who should use TricelSiteAssessors?

TricelSiteAssessors website is perfectly suited for the needs of:

• Site assessors
• Engineers
• Architects

What wastewater treatment systems are available?

Seven types of report are available, the most suitable solutions will vary depending on the site conditions.

1. Septic tank and percolation area
2. Wastewater treatment plants and gravity or pumped soil polishing filter (Secondary Treatment)
3. Wastewater treatment plants and pressurised soil polishing filter (Secondary Treatment)
4. Wastewater treatment plants and sand polishing filter(Tertiary Treatment)
5. Septic tank with Tricel Puraflo and percolation area (Secondary Treatment)
6. Wastewater treatment plant with Puraflo (Tertiary Treatment)
7. Septic tank with Puraflo and soil polishing filter (Secondary Treatment)

The reports are available to cater for a wide range of applications from single houses to light industrial applications (up to 50 PE).

A PE Calculator will enable you to quickly calculate the PE for non-domestic applications using either the EPA Wastewater Treatment Manual – Treatment Systems for Small Communities,Business, Leisure Centres and Hotels or British Water’s Flows and Loads – 4.