Initial commissioning experiences of meeting lower total phosphorus permits: PRESENTATION ONLY
Longhurst, C.1, Baloch, I.2 and Jarvis, S.2, 1Costain (CMDP), UK, 2Southern Water, UK
(free)
Southern Water’s AMP6 capital programme is delivered in a partnership between Strategic Solutions Partners (SSP), construction Delivery Partners (DP) and Southern Water. Stantec UK are part of the Engineering Team within the SSP who have designed innovative solutions which are now being constructed and commissioned by the DPs, to meet tightened environmental wastewater regulatory permits, driven by the Water Framework Directive. The DP providing the construction and commissioning services in East Sussex and Kent is CMDP – a joint venture between Costain and MWH Treatment.
For many new phosphorus (P) removal sites, March 2020 is the predominant regulatory compliance permit date to be met. However, 6 wastewater sites in Kent and Sussex were given earlier P permit dates in March and November 2018, which were successfully met.
The challenges of commissioning ferric and alkalinity dosing equipment at sites with low ammonia and low annual average Total Phosphorus permits (the lowest being a TP of 0.5mg/l with a Real Time Control feed forward controller) shall be discussed.
Furthermore, a new baseline control philosophy has been developed to accommodate site requirements. This is now at the stage of being implemented across a new batch of ferric and alkalinity dosing plants. The software allows for inter-stage ammonia and pH monitors to regulate alkalinity dosing; and for final effluent pH, iron, turbidity and phosphorus monitors to feedback to adjust ferric dosing.
The paper shall highlight the issues faced during commissioning of the initial versions of the software feedback control.
