Problem: Laurel Regional Airport Authority of Hattiesburg, Mississippi, had an undersized 20,000 gpd wastewater treatment system servicing the airport and local business park. Treated effluent discharges to a Pascagoula River Basin tributary. When the authority applied for an updated permit for an increased flow of 50,000 gpd, the state conducted a waste load allocation study and imposed more stringent permit parameters including BOD from 30 mg/L to 14 mg/L, 6.0 mg/L dissolved oxygen level and 2.0 mg/L total ammonia levels, and nutrient monitoring.

Solution: The authority selected an extended aeration package plant from Infiltrator Water Technologies that meets the 50,000 gpd requirement and NPDES parameters and allows extensive operator control based on actual flows and loading. Effluent from generating facilities gravity flows through a manual bar screen to a flow equalization tank with duplex alternating pumps. The adjustable pump timer accommodates fluctuating flows. Effluent then moves to a flow-proportioning box with overflow returning to the flow equalization chamber, while the standard flow travels to the aeration basin where treatment occurs. After treatment, effluent flows into a double hopper clarifier, where solids settle. Clarified water flows to the tertiary sand filter ensuring low-level limits are consistently met and then through a disinfection chamber to a post-aeration chamber. Water then exits the treatment unit via a discharge pipe to the tributary.

Result: The system has complete operator adjustment in mind. The process ensures permit parameters are met under fluctuating conditions and the receiving water body is not negatively impacted. 

800-221-4436; www.infiltratorwater.com