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Research Project Information

Research Project Summary Information

Demonstrate Membrane Bioreactor Technology at Harriman WWTP(ST8135-1)

Orange County


Unprecedented growth in Orange County has placed a burden on existing infrastructure, including the Harriman Wastewater Treatment Plant (WWTP). The four million gallon per day (mgd) plant consists of two parallel treatment process trains: a two mgd oxidation ditch constructed in the late 1980s and the original two mgd conventional activated sludge treatment process constructed in the 1970s. In March 2003, the county received approval to increase the capacity of the facility from four mgd to six mgd (Phase I Improvements). Implementation of Phase I Improvements represents a significant step in addressing the demands on the sewer district. Continued growth has prompted the county to plan for a second expansion (Phase II Improvements); however, expansion is limited by lack of property. Orange County chose to conduct a pilot study to establish the feasibility of using small-footprint membrane bioreactor (MBR) technology to upgrade and expand the treatment capacity of the WWTP. If deemed feasible, the county would subsequently retrofit its existing oxidation ditches with MBR technology, which would bring the total capacity of the Harriman WWTP to eight mgd.

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Project Description

The goal of the pilot study was demonstrating the viability of MBR technology for use at the Harriman WWTP. Data collected during the pilot would be used to estimate the treatment capacity that could be provided within the existing tankage through installation of MBRs, and to compare an expansion with MBRs to a more conventional treatment technology (i.e., step-feed aeration). Based on the necessary improvements required to increase capacity, as well as planning level capital costs and additional annual operating costs, the present value based on a 20-year life cycle were estimated for both alternatives.


Preliminary estimates for converting the existing system to MBRs are on the order of $10 million, which compares to $25-30 million (in 2004 dollars) for the conventional expansion estimated for the Phase I Improvements. MBR technology would: allow for significant expansion of the plant's treatment capacity without requiring additional land acquisition, provide for a significantly better effluent quality (potentially of reuse quality), and minimize the quantity of waste sludge produced by the facility.

Project Results

An MBR-expanded facility would increase the total amount of energy used at the WWTP, which is not surprising since the treatment capacity will also be increased. However, the MBR facility would also out-perform the conventional system environmentally. Based on the conceptual designs, cost estimates, and constructability issues, the MBR system has more potential benefits (compared to step-feed aeration). On a present worth basis, the MBR system is approximately $6.8 million less than the step-feed system over a 20 year period.


Orange County
255 Main St
Goshen, NY 10924

Principle Investigator

Thomas Schoettle

Universities Involved


Project Type:

Product Demonstration

Technologies Types:

Waste Management and Pollution Prevention
Water/Wastewater treatment systems

NYSERDA Contact Information

Kathleen O'Connor


R&D - Environment & Energy Res

Contract Details

Start Date: 1/11/2010
Project Status: Active
Contract Number: ST8135-1

Last Updated: 11/13/2013