The purpose of the project is to remove phosphorus from the plant discharge following the authorities’ notification of the removal of the discharge exemption for the phosphorus parameter.

The existing treatment involved digestion with the UASB process, which effectively removed the compounds characteristic of food waste, but was not able to effectively remove phosphorus, a parameter for which an exemption was provided at the disposal stage.

The engineering development allowed for an initial neutralisation of the effluent by dosing soda ash into a new UASB equalisation and feed tank, the change of use of an existing storage tank to a reaction tank for dosing reagents for the formation of sedimentable hydroxyapatite, and the installation of a truncated cone sedimenter for the clarification of the effluent prior to discharge into the sewerage system. Auxiliary systems such as lime storage and dosing system (storage silos and preparation/dosing tank) and reagents, auxiliary utility lines, sludge line for sludge dewatering and supernatant recirculation were also engineered.

The implementation has minimised plant downtime, as the production site is operational all year round.