Honolulu Membrane Bioreactor Pilot Study
Year Released: 2009
Program: Tailored Collaboration
Funding Partner: Bureau of Reclamation
Total Investment: $290,000 (Cash: $125,000, In-kind cash and service: $165,000)
Principal Investigator: Roger Babcock, Jr., Ph.D., University of Hawaii
The current state of wastewater treatment/disposal/recycling and its integrated relationship to drinking water supply in Hawaii is varied. The story on each of the five major islands is somewhat different and the focus of this project is the Island of Oahu, location of the state capital in Honolulu, and home to more than 70% of the population (but less than 10% of the combined land area). Oahu, with a population of approximately one million, is the 51st most populous metropolitan area in the United States and has an area of approximately 600 square miles. Oahu consists of the single county of Honolulu which functions as the major municipal water purveyor and the major municipal wastewater treatment and disposal provider. To help facilitate the increased adoption of water reuse, the demonstration of new treatment technologies , including membrane bioreactors (MBR), is needed.
Goals and Objectives
The project consisted of a side-by-side pilot demonstration of six different membrane bioreactor (MBR) systems at the Honolulu wastewater treatment plant (WWTP) in Ewa Beach, Hawaii, and a variety of activities, including bench- and pilot-scale tests, aeration testing, and a feasibility study.
The objectives of Phase I were to (i) demonstrate the technology for local engineers, operators, owners, and regulators, (ii) develop operating experience in Hawaii, (iii) promote the technology for adoption in Hawaii, (iv) compare different equipment, and (v) investigate the consistency of water quality, the reliability, and the operability of the technology for three different waste streams.
The objectives of Phase II were (i) pilot testing one MBR at an application site to facilitate the full-scale plant design and acquaint the operations staff with the technology, (ii) pilot testing one MBR at a pump station site to evaluate satellite MBR treatment operation issues, (iii) pilot testing MBR-based thickening and aerobic digestion of secondary sludge to investigate the potential utility of such operations, (iv) conducting a comprehensive MBR feasibility study for the island of Oahu, including satellite reclamation, plant expansions, plant upgrades to facilitate recycling, and decentralized treatment for proposed or new developments, and (v) conducting research on MBR biofouling and aeration mass transfer.
Findings and Conclusions
The objectives of this study were achieved with MBR technology introduced and demonstrated effectively. Familiarity with MBRs increased such that they have been proposed for numerous projects statewide and adopted in Oahu. The six MBRs compared in this study were of different configurations but they all produced similar high-quality permeate with reliability that was of a higher quality compared conventional activated sludge effluent. MBR permeate was found to be suitable for UV disinfection and MBRs were found to be able to be operated reliably under a variety of conditions.