Stainless Steel Acid Dosing System For SSI Aeration Diffusers

DESCRIPTION

The cleaning system consists of a pump unit, a dispensing manifold, a control box, valves, and nozzles. The pump unit draws formic acid from the vessel and sends it through the dispensing manifold to the nozzles, which spray formic acid into the risers (Figure 2-1). The pump operation time is set by the control box and the aeration units are cleaned one by one.
The cleaning system can be a stationary or mobile unit. The mobile unit is mounted on a cart for easy transportation.

The stationary system can be operated automatically if required. Acid addition can be regulated by a loading solenoid valve, which is controlled by a timer that regulates the number of valve openings. Similarly, the start-up and regulation of the system can be automatically controlled by changes in back pressure.

Operating Instruction

Observe back pressure to determine when the aerator should be cleaned. Check back pressure periodically and record observations in the WWTP records. Back pressure must always be measured at a constant airflow rate or at a known air flow rate.
Due to the availability of SSI's cleaning system, it is recommended that the aerators be cleaned frequently or whenever the back pressure rises to 20 mbar. Cleaning intervals are plant-specific and can range from one week to one year depending on local conditions.

Adjustment of pump feed rate
The pump feed rate is determined by the size and airflow rate of the aeration unit to be cleaned and the amount of acid supplied. Figure 4-1 shows the required acid pumping rate (l/h) for different-sized aeration units at different air and acid supply rates.

Aeration Cleaning

To clean the aerator, do the following:
- Vent the compressed air from the acid supply line before performing the cleaning. Remember to close the discharge valve.
- Open the shut-off valve of the acid supply pipe of the relevant aeration unit.
- Ensure that supplementary air is allowed to enter the acid container during pumping, otherwise, the acid will evaporate. Use the control box to set the pump
Set the pump run time using the control box.
- Start the pump.
- When the pump stops, close the valve of the relevant aeration unit acid supply hose.

It is usually recommended that acid be added to one aeration unit at a time to ensure that formic acid is supplied to the exact designated point in the system. In small wastewater treatment plants, all aerators may be cleaned at the same time.

If the pump suction and supply lines become empty, the supply lines must be depressurized to ensure that the pump can draw the liquid to be dispensed. This occurs when the acid container is slowly emptied and the pump begins to draw air.

Installation

The fixing system includes the following devices:
- Pumps
- Pumps
- Suction hose
- Pressure relief valve
- Tee valve
- Shut-off valve, one for each aeration unit
- Power cable
- Protective device