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.