Date
Monday, September 9, 2024
Time
2:00 PM - 2:30 PM
Location Name
M104
Name
Evaluation of the Carrollton and Bardstown Trickling Filters
Track
Water Resource Recovery
Description

Trickling filter wastewater treatment technology was developed in the 1890s. In the next few decades, light weight, high-surface-area plastic media and rotary distribution systems with speed control were introduced, which have significantly improved the treatment efficiency of the filters. From the late 1970s to early 2000s, many modern trickling filters were built in U.S. Most of these filters are still in operation today and are meeting today’s wastewater treatment needs. This presentation will discuss the trickling filters in two wastewater treatment plants in Kentucky that have been operated for 20 years. Jerry L. Riley WWTP at Bardstown, KY has two (2) trickling filters in parallel, each filter is 60’ in diameter by 28’ media depth. The trickling filters are downstream of aerated lagoons for BOD polishing and nitrification. A high-density cross flow media with a specific surface area of 48 ft2/ft3 was selected to maximize the filters’ nitrification capacity. The plant is receiving an average flow of 4 MGD from municipal and industrial sources, including landfill leachate. The trickling filters were originally installed in 2001and have been consistently achieving the required treatment (ammonia N of less than 2 mg/L in summer and 4 mg/L in winter). The plant effluent ammonia nitrogen has been well below the 1 mg/L during most months of the year, which exceeds typical expectation of a nitrification performance of a typical nitrifying trickling filter. Carrollton wastewater treatment plant in KY also has two trickling filters in parallel, each filter is 52’ in diameter by 28’ media depth. Like Bardstown WWTP, the trickling filters are downstream of aerated lagoons for BOD polishing and nitrification. Cross flow media with a specific surface area of 48 ft2/ft3 was selected for nitrification application. The trickling filters were originally installed in 2005 and have been consistently meeting the discharge limits with minimal effort on operation and maintenance. Carrollton WWTP will be expanded to handle increased ammonia loading from industrial users. Because of the reliable performance, simple operation and energy saving features, additional trickling filters will be considered for this expansion. This presentation will discuss the evaluation of the trickling filter process, including performance, capacity, and best practice of operation. In addition, the media condition of the filters has recently been assessed. Findings and recommendations will also be presented. Modern trickling filters are environmentally friendly and reliable biological treatment systems that should be given full consideration in 21st century wastewater treatment plant design. With proper engineering, operation, and maintenance, trickling filters can provide many years of simple, effective, and low-cost treatment.