ENVICON - Model Type EAD - Formic Acid Dosing Station
ENVICON Formic Acid Dosing Stations are used to clean and regenerate the ENVICON Aerators, Types EKR/EKS and EMR/EMS with 85% formic acid. The wastewater constituents cause organic and inorganic deposits to form on the ceramic components and as well as on the membranes and in the slits of these, which increase the loss in operating pressure and reduce oxygen input. As a result, the operating costs also increase. Slight organic deposits can be removed by momentarily increasing the specific air flow.
Tenacious deposits (e.g., lime) can, however, only be removed by dosing formic acid into the air stream. The tank need not be emptied in order to do this. Depending on the degree of pollution, between 0.5 and max. 1 litre 85% formic acid per aerator, or per meter aerator, is dosed into municipal wastewater treatment plants twice per year in small amounts of approx. 1 litre formic acid per 100 Nm3/hr air. The precise amount and dosage depend on the composition of the wastewater and the mode of operating the wastewater treatment plant and can only be determined by means of appropriate tests.
For dosing purposes, high-grade stainless steel connection flanges, R11/4', are provided in the downcomers by the operator, as well as a CE connector directly beside the down-comer. It is then only necessary to unscrew the blank flange at the respective dosing point and attach the specially designed dosing device to srew in. The dosing station consists of the following components:
- Trolley (with collection trough) for transporting the dosing equipment
- Polyethylene formic acid tank (with level indicator), ready for installation of the dosing pump
- Suction line (length adjustable to the height of the PE formic acid tank)
- Membrane-type dosing pump (non-leak, geared-motor pump with non-return valves on the suction and delivery sides; the delivery rate is manually adjustable; all components coming in contact with the media are resistant to chemicals)
- Pulsation dampener (of plastic, with tubular membrane, to generate a low-pulsation, continuous flow of chemicals to the dosing point)
- Pressure-retention and overflow valves (for installation in the dosing line downstream the pulsation dampener (pressurizing function) and for installation in the bypass line of the dosing pump, incl. return line to the storage tank (overflow function))
- Dosing hose (with a textile core; for connection to the pressure side of the pressure retention valve; equipped with hose nozzle and screwed connection on the discharge end)
- Special high-grade stainless steel dosing unit with a high-grade stainless steel hollow-cone nozzle, Rl'/4' flange connection with ball valve (the 1/2' dosing tube is welded into a high-grade steel blank flange to allow connection to the Rl'/4' flange connection provided by the operator
The unit is supplied completely preassembled and ready for operation. The storage tank is firmly mounted on the high-grade stainless steel equipment trolley. The dosing devices are accommodated on the polypropylene cover of the tank and provided with connection tubes.
The formic acid dosing stations are available in the following four standard sizes: