Condition Assessments for High Risk Man Holes and Wastewater Pump Stations

⁠⁠⁠The Principal has approximately four hundred and forty four Wastewater Pump Stations (WWPS) and seventy four thousand Maintenance Holes (MH) in its sewerage network. There have been an increasing number of MH failures this year which pose subsequent increasing safety and operational risks to the organisation. A short term asset management plan is required to address the unknown condition of the deemed higher risk WWPS's and MH's that may be subjected to highly corrosive environments. It is not feasible to condition assess the seventy four thousand MH's so a selection criteria is required.

The conditions known to increase the likelihood of H2S corrosive conditions were consolidated into the below criteria;
* Anywhere a pressure sewer discharges (both PSS and CEP systems);
* Any VGS (variable grade sewer);
* Barometric loops and other drop structures;
* Receiving MHs at rising main discharge points;
* WWPS wet wells or collecting MHs where the WWPS receives direct pumped flow and/or part of a long daisy chain.

The objective of this project is to reduce the operational risk and improve the public safety by undertaking condition assessments of the MH's and WWPS's with a high risk of deterioration associated with concrete corrosion.