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 recirculated through the trickling filters.
The main purpose of the sodium hypochlorite system is the disinfection of secondary flow. The process strives to eliminate the presence of pathogenic organisms from the plant flow. Sodium hypochlorite acts as a disinfectant because of its toxicity to certain microorganisms at appropriate concentrations. This process protects the integrity of the receiving waters by improving the quality of the wastewater.
Disinfection takes place in the chlorine contact chambers. One chamber serves treatment train three and one chamber serves treatment trains one and two. The flow is dosed with sodium hypochlorite and detained 30 minutes in the chamber. The chambers discharge into the stabilization pond which is the polishing point of plant.
The equalization facilities consist of an aerated storage basin (stabilization pond in aerial view) which helps even out the flow and strength of the wastewater. The flow is detained for three to five days in the pond, and some additional settling takes place before the flow becomes plant effluent. Upon discharge from the pond the flow is again dosed with sodium hypochlorite.
Ocean Outfall Graphic-coming soon
Discharge from the pond is through a 36 inch and 24 inch outfall line. The total trip is nearly four miles, which discharges 5,800 feet off the shore line between Bradley Beach and Avon.
Solids digestion is a biological process involving the anaerobic (in the absence of air) decomposition of organic matter contained within the sludge. It uses several types of microorganisms to convert complex organic reactants to products of volatile acids, methane, carbon dioxide and water and thereby achieves waste stabilization. The process is conducted in a series of vessels called digesters using heat and mixing to carry out the reaction.
The Authority operates three digesters. The first digester is used to mix the waste received from primary clarifiers and scum pits. It discharges to the second digester, where the wastes settles. From the second digester the waste is sent to a holding tank digester where final settling takes place to produce a thicker sludge. The sludge is then removed by pumping it in a semi-liquid form to privately owned and operated tanker cars which haul it away to other facilities. These facilities have appropriate means for final disposal. In the course of one year approximately 2 million gallons of sludge is removed from the system.