Background on Suffern WWTP
The Village of Suffern Wastewater Treatment Plant is located in Suffern, NY. The Town has a population of 11,338 and serves as a gateway to the Hudson River Valley National Heritage Area.
Challenge
Since 2015, the Treatment Plant has been experiencing problems. Many of the plant’s processes were in disrepair, especially its biological processes. The plant relied on mechanical aeration and an integral clarifier-activated sludge system that never worked properly. To avoid costs, the plant focused on cheap solutions that did not offer long-term benefits.
After consulting with Delaware Engineering, the plant allocated additional budgeting for an MBBR retrofitting project. Based on our successful Allentown, NJ IFAS Project, PSI recommended Headworks as a supplier.
The MBBR (Moving Bed Biofilm Reactor) process involves high-density polyethylene (HDPE) biofilm carriers and can be used with heterotrophic and autotrophic bacteria. The biofilm carriers provide a medium to large surface area for bacteria attachment. The biomass attached to the media is typically equivalent to up to 3x the biomass per unit volume in a conventional activated sludge (CAS) process. For this reason, the MBBR is able to treat up to 3x the flow and organics load in the same reactor volume as in a CAS, thereby saving valuable footprint and costs.
Moreover, the biofilm attached to the media is much more robust and resistant to toxic loads and shock. It results in a cost-effective and expandable wastewater treatment focused on BOD Reduction, ammonia reduction, and Total Nitrogen Removal.
The Suffern CAS plant was retrofitted to handle higher flows and loads and meet a new stringent limit for ammonia-nitrogen of 1 mg/l. Headworks designed a two-stage, two-train MBBR system (one stage each for BOD removal and nitrification) to provide flexibility and redundancy.
Headworks supplied the ActiveCell920™ media with 680 m² per m³ of internally protected surface area for the MBBR process. This is due to the media’s optimum apertures that handle both BOD removal and nitrification. Suffern WwTP consistently met an effluent ammonia concentration of 1 mg/l or below during startup in 2022 and subsequent operation over the next 24 months. Headworks designed the treatment for < 4 mg/l effluent ammonia in summer and <7 mg/l in the winter.
The Engineer for this project initially worked with another manufacturer, which resulted in an atypical design with three aeration headers. The original tank was designed for a flow of 676 BOD (lb/day) and required an Alkalinity level of 320 (mg/l). The assumed alkalinity in the wastewater was enough to handle nitrification. The design temperature ranged from 10 – 20° C, and the pH level ranged from 6-9.
Suffern’s existing tanks were retrofitted to accommodate the MBBR. By adding a wall in the middle of each basin, two trains, each with an MBBR tank, were created. MBBR was seeded one train at a time, simplifying the process’s startup and continuously meeting the effluent requirements without downtime for the treatment plant.
Since the implementation of MBBR, Suffern WwTP has not had a violation. All effluent levels have been met and sustained. Ammonia levels are as low as “less dense,” and CBOD is listed as “non-detect.”
Biofilms growing on ActiveCell media provide a more resilient, dense treatment population per unit volume than conventional suspended growth-activated sludge systems.
Project Consultant: Delaware Engineering
Headworks Representative Firm: PSI Process / Pumping Services, Inc.
