The site comprises the STP Compound and two oxidation ponds, which cover an area of
approximately 1.5 to 2 hectares (ha). Within the STP Compound are several buildings,
primary treatment ponds, pipes, tanks, two large trickle filters and associated

Investigations were completed within the site and adjacent to the site. The
investigation identified elevate nutrients within soils and groundwater at the site, biological
constituents in soils down gradient of the STP area and asbestos containing materials
(ACM) along the STP boundary. Additionally, TPH and biologicals were reported in sewer
sludge. The TPH concentrations were attributed to organic matter in the sediment.

The preferred remedial option was to excavate impacted fill materials for potential onsite
containment with management under an Environmental Management Plan (EMP) with
onsite treatment and retention of biologically impacted materials. DECC’s Scope of Works is summarised below:

  1. Construction of a 25,000 cubic metre containment cell with capping layer required for the importation, placement and compaction of asbestos contaminated soils (ACS);

2. Miscellaneous works (environmental protection, desludging, dewatering and remediation of oxidation ponds) + contouring and shaping site to final landforms.