The activated sludge process derives its name from the particular biomass formed when the air is continuously injected into the wastewater. In this process, micro organisms are mixed thoroughly with the organics, under conditions that stimulate their growth through the use of the organics as food. As the micro organisms grow and are mixed by the agitation as food. As the micro organisms clump together (flocculate) to form a suspended culture of biomass termed ‘activated sludge’. In practice, the wastewater flows continuously into an aeration tank where air or oxygen is injected to mix the activated sludge with the wastewater and to supply the oxygen needed for the suspended biomass to break down the organics. In conventional activated sludge systems, the wastewater is aerated for 6-8 hours. The mixture of activated sludge in the aeration tank, termed ‘mixed liquor’, then flows from the aeration tank to a secondary clarifier, where the activated sludge is settled out. A portion of the settled sludge is returned to the aeration tank to maintain the high population of micro organisms necessary for the rapid breakdown of the organics. Because more activated sludge is produced than can be used in the process, some of the return sludge is diverted to the sludge handling system for treatment and ultimate disposal.

Diffused aeration through aeration membrane tubes/ pads/ discs has completely replaced the Surface aerators due to reduced space requirements and improved efficiency factors.

Fine bubble diffuser membranes (fixed type/ removable type/ removable grid type employed) help in providing an even distribution of air to the microbes across the basin. Air is supplied by Aeration blowers and more often the aeration volume is automatically adjusted with the Dissolved Oxygen in the aerated effluent to save power.

The biologically treated effluent is transferred to Secondary Clarifiers.

The sludge from the clarifier is continuously re-circulated to the Activated Sludge process to maintain the MLSS and a part of the bio-sludge is periodically wasted. The wasted bio sludge is de-watered with the de-watered sludge is sent to land fill sites.

Paramount has designed, installed and operated more than 100 Activated Sludge Process biological treatment in varied types of effluents from a multitude of industries including high Nitrate, BOD contaminants.

Extended Aeration Process

The extended aeration process is much similar to the Activated Sludge process. The major difference being that an extended aeration process has a much larger residence time and do not require a primary clarifier unit prior to the biological process. The extended aeration process also generates a good settleable sludge and a clearer overflow compared to the Conventional activated Sludge process. The reduction in BOD and COD is also better than the Conventional activated Sludge process.