Optimisation of Extended Aeration and Design of a Reed Bed Treatment System

This Vegetable Processor prepares and freezes fresh vegetables including peas, carrots and onions. The existing aerobic effluent treatment plant incorporated screening, primary sedimentation and three aerated lagoons operating in sequence in extended aeration mode. The treatment system became overloaded, particularly during the warm "pea season" between July and September each year. This is a time when ambient temperatures rise and it becomes increasingly difficult to dissolve oxygen into solution, to feed the aerobic mocroorganisms. Frequently aerobic plants which only just work in the winter months do not have sufficient additional capacity to deliver the increased areation required in warmer months.

EBL provided a comprehensive response starting with its unique Waste Audit, working closely with representatives on site. Once the problem was defined specific proposals could be drafted to reconfigure the treatment system, incorporating increased settlement capacity with the installation of five settlement ponds as well as additional aeration. In order to ensure the maximum potential of the system, a novel Reed Bed Treatment System (RBTS) was designed and installed after the lagoon system to improve effluent quality.

The new effluent treatment plant has proved effective in ensuring that effluent quality is maintained throughout the year achieving a tight compliance window.

Existing Aeration Lagoons