PRIMARY TREATMENT

The primary treatment takes place in each of the Authority’s three primary clarifiers (settling tanks) and is a physical separation process which removes settable and floating solids. The influent is introduced into a primary settling tank where sufficient time is provided for solids to either settle to the tank bottom (sludge) or float to its surface (scum and grease). Both types of solid accumulations are mechanically collected and the sludge is sent to the primary digester while the scum and grease solids are sent to the scum pit for further treatment. Approximately 60 percent of the solids are removed at this stage.
 

SECONDARY TREATMENT

The secondary treatment process is designed to remove contaminants in the wastewater and occurs in the three trickling filters and three secondary clarifiers. Trickling filters receive their flow from the primary clarifiers. The influent is equally distributed on the trickling filter which consists of an 8-foot stone bed with clay under drain system. The discharge from trickling filters flows to secondary clarifiers where a further settling process occurs. The solids that settle in the secondary clarifiers are pumped to the head of the primary clarifiers. Secondary clarifiers generally discharge to chlorine contact chambers with some flow being re-circulated through the trickling filters.