PROCESS DESCRIPTION

The principle of the Aquaco Electroflotation System is based on the electrolyses process. The reactor contains Fe- (iron) and Al- (aluminium) electrodes. Four of them are connected to the anode (+) the other four are connected to the cathode (-)1. The voltage-level varies between nine and eleven Volt.

The Fe- and Al- electrodes connected to the anode are slowly converted into Fe203 and AL2(0H)3 These rough formed flocks are very suitable as place of attachment for any pollution in the water. The dissolved contamination is connected to the flocks and so it is transformed into non-dissolvable particles. These particles can easily be separated from the treated water by filtration.

The contaminated water is pumped into the reactor with an adjustable flow of maximum 500 litres per hour. The current should be between 450 and 500 Ampere. If this value of current is not achieved, adding a salt-solution into the water will increase its conductivity and so the current will rise. This brine-injection is automatically arranged by an installed regulation system. After reaction the flocculated water flows into the flocculation vessel. From this vessel it is pumped through the filterpress. All the formed particles remain between the filtercloths in the press and the cleaned water flows out of the filterplate-outlets into the collection gutter. Between the filtercloths a firm filtercake is formed which can be easily removed by opening the press.

The entire process of inlet, outlet and reaction is controlled by a LOGO PLC in the switchbox. This PLC also controls the essential process parameters such as the temperature on several places in the unit, the current and voltage level in the reactor and the water level in the vessels.

The energy consumption and the iron and aluminium usage of the unit is of course related to the reaction current and the amount of pollution in the water. On the average the consumption is approximately 7,5 kWh, 40 gr. Fe and 20 gr. Al per m3 treated wastewater.

Influentbuffer

The wastewater is collected in the influentbuffer. In this tank there are at least two level- sensors. When the lower sensor (LL-level) is active, the installation is ready to start.

Reactor

The flocculation process in the reactor is based on electrolysis. Depending on the current through the water the voltage on the anodes varies from 9 VDC to 11 VDC.

When the installation is switched on, air is blown through the water in the reactor. This is to keep the water in motion and to prevent solids sink to the bottom. Every thirty seconds an extra boost of “cleaning-air” is blown through the water.

The pressure of the process- and cleaning air can be adjusted by the throttle valves inside the switchbox.

Flocculation vessel

The flocculated water flows from the reactor into the flocculation vessel. In this vessel there are three level-sensors. When the lower level-sensor (L-level) in the vessel is active, the press pump is switched on. When the H-level sensor is active, the installation switches to standby mode. Reactor and supply pump are switched off, press pump stays active.

The higher level sensor (HH-level) is an alarm sensor, when it is active, installation stops and in the display is an error-message.

Above the flocculation vessel there is a sprinkler. The sprinkler controls the foam-level in the vessel. The on / off timer of the sprinkler can be adjusted.

Filter press

The filter press is closed by a hand operated hydraulic system. The closing pressure must be about 350 bar.

The water is pumped through the press with a maximum pressure of about 10 Bar.

The resulting cake is easily disposed of or recycled.