Control of activated sludge wastewater system

Abstract

There are several stages in wastewater treatment plants (WWTP) before it can be released to a receiving water body as shown in Figure 4.1: a preliminary treatment (mechanical treatment), a primary treatment (primary sedimentation), a secondary treatment (biological treatment) and a tertiary treatment (chemical treatment). Initially, the first treatment or so-called mechanical treatment is applied which included both preliminary and primary treatments. In preliminary treatment, large and heavy objects like solid debris, grease removal and flow equalisation are passing through grid removal by sedimentatio n. Therefore, lighter particles are passing through primary sedimentation or primary clarifiers. Generally, this stage is to ensure the wastewater passing to the subsequent stages is clean an d could not disrupt the plant operation.