Community-scale secondary treatment
Reactor columns constructed from plastic drainage cells provide cost-effective community-scale secondary treatment vermifilters. The drainage cells provide cavities for ventilation between reactor columns, for multiple deep reactors. Vermifilters without ventilation cavities have a working depth of approximately 30-40cm because below that the substrate becomes anoxic, which severely limits the level of treatment. By providing ventilation cavities between reactor columns, the working depth increases to as much as 3m. The drainage cells themselves become the structure, attached together using cable ties.
Drainage cells offer a cost-effective scaleable, modular system for matching media volume to influent volume, which is scaleable for increased demand, installed in parallel (number of reactors per module) or in series, or a combination of both.
Plastic drainage cells are the best option for constructing ventilated columns. They are tied together with cable ties into a structure that walls and roof are attached to:
The structure can be as wide and as high as required.
A textile "sock" is made from windbreak or shadecloth and inserted into each cavity. The sock is then filled with media for each column, with ventilation between columns. Walls may be attached to the outside of the structure and a roof constructed if necessary.
A false floor is required under the structure. This can be made from plastic pallets.
Usually the pallets would sit on a steel-reinforced concrete pad that directs the treated water to an outlet.