In 2004 the wastewater treatment plant in the Town of Orange Park had a very unique problem. The Town was in violation of the current Water Quality Based Effluent Limits (WQBEL) permit while they were simultaneously planning for the even more stringent, Basin Management Action Plan (BMAP) permit to take effect in 2008. The Town needed to address both long and short term wastewater treatment effluent quality challenges and they turned to In-Pipe Technology’s collection system bioaugmentation treatment as a part of their action plan.
The WQBEL permit for the Town of Orange Park limited their discharge of total nitrogen into the St. John’s River to 150 pounds per day. Under this permit, the Town was out of compliance about 60% of the time because the contact-stabilization process that they used for wastewater treatment was not designed for Nitrogen removal.
The Town of Orange Park and their Consulting Engineer, Legacy Civil Engineers, Inc., developed a plan to retrofit the three small contact stabilization
treatment units one at a time into two modified Bardenpho trains and one equalization tank. During the retrofit the plant had to maintain compliance with the WQBEL consent order, which enforced a temporary limit of 300 pounds of nitrogen per day during the construction period.
The project included three separate stages. During each stage, one of the three process trains was modified from contact stabilization to extended aeration, to Bardenpho. Concerned that the construction activities required for the renovation of the wastewater treatment plants could compromise biological treatment or upset the treatment processes, the Town initiated a collection system bioaugmentation program with In-Pipe Technology® Company, Inc.
This case study will examine the effects of the In-Pipe program on the first stage of construction. During this time period the plant was operating the same process that it had before retrofit, contact stabilization, with 20% reduced treatment capacity.
IN-PIPE TECHNOLOGY PROGRAM IMPLEMENTATION
In-Pipe Technology introduces high concentrations of facultative, heterotrophic, nonpathogenic bacteria to strategic locations throughout the sewer system. The microbial dosing continues constantly in order to replace the wild sewer biofilm with optimized microbiology which contributes to the enhanced degradation of pollutants in the wastewater as it travels to the treatment facility.
The application of In-Pipe microbiology is accomplished by installing numerous G2 dosing panels into strategic areas of the collection system. The G2 dosing panel is a small, waterproof enclosure housing a battery-powered solenoid diaphragm pump, control electronics and batteries. The G2 panels are
small, simple to operate and are easily installed to facilitate coverage of the complete wastewater collection system.
The In-Pipe blend of naturally occurring soil bacteria, delivered constantly into the collection system, transforms a normally passive conveyance system into an active part of the treatment process. This approach initiates a gradual repopulation of the sewer biofilm by bacteria that are more efficient at degradation of organic material than the bacteria that are present in untreated conditions. As the In-Pipe bacteria enter the treatment facility, they enhance biological treatment and nitrogen removal, improving process operation and control.
RESULTS OF TREATMENT
Before In-Pipe treatment, the average influent wastewater five-day carbonaceous biochemical oxygen demand (CBOD5) was 290 mg/L or 2,258 pounds per day. Over the first 16 months of treatment the influent CBOD5 dropped by more than 50% to 139 mg/L or 1,085 pounds per day.
The effect on total suspended solids (TSS) was similar: before treatment the average influent TSS was 354 mg/L (2,784 pounds/day) and after treatment influent concentrations dropped by 23% to 273 mg/L (2,250 pounds/day).
Effluent Water Quality
The Orange Park WWTP was effectively treating the wastewater for CBOD5 and TSS prior to the In-Pipe program. However, results during treatment show an improvement in effluent CBOD5 (from 3.3 mg/L to 2.4 mg/L) and a modest increase in effluent TSS (from 2.4 mg/L to 2.6 mg/L).
The Orange Park plant could not effectively remove nitrogen from the wastewater to the levels required by the WQBEL permit before IPT treatment. Before treatment, the plant averaged 19.3 mg/L of total nitrogen (TN) in the discharge. During In-Pipe treatment, the effluent TN decreased by 30%, to 13.5 mg/L. This reduction rendered them compliant with the 2004 WQBEL without any capital expense and while operating the plant with only 80% of the original biological treatment capacity.
This case study focuses on the first 16 months of treatment for a collection system bioaugmentation project that has lasted over three years and is ongoing. So far the Town has decommissioned and recommissioned their various package plants 7 times. They have processed major rain events with limited capacity while preserving high effluent water quality.
Throughout the construction, In-Pipe Technology treated the collection system with beneficial bacteria that reduced the pollutant load to the treatment plant and constantly seeded the process with optimized microbiology to maintain consistent, effective treatment.
During In-Pipe treatment, the influent CBOD5 and TSS load to the Orange Park treatment facility decreased by 50% and 23%, respectively. Additionally, effluent nitrogen dropped by 30%, to the level that the plant could have been compliant with the WQBEL permit without any process modifications. The Town of Orange Park continues the In-Pipe Technology collection system bioaugmentation program after completing the first phase of the wastewater treatment plant modifications. The benefits of reducing the influent load, improving nitrogen removal as well as controlling collection system FOG, odor and corrosion will continue long after construction is completed.
In-Pipe would like to thank the Town of Orange Park and Legacy Civil Engineers, Inc. for their cooperation.