Evaluation of an osmotic dilution process for tertiary wastewater treatment

Graduation Date

2014

Document Type

Project

Program

Other

Program

Project (M.S.)--Humboldt State University, Environmental Systems: Environmental Resources Engineering, 2014

Committee Chair Name

Andrea Achilli

Committee Chair Affiliation

HSU Faculty or Staff

Keywords

Wastewater treatment, Forward osmosis, Osmotic dilution, Humboldt State University -- Projects -- Environmental Resources Engineering, Nutrient rejection

Abstract

Municipal wastewater treatment practices in the United States largely consist of preliminary, primary, and secondary treatment. These processes remove large debris, suspended solids, and organic waste, but do little to address nutrient removal and disinfection. As a result of increasing environmental concerns associated with the quality of water being discharged, more stringent regulations will likely be implemented in the future that require tertiary treatment. The current study investigated the application of osmotic dilution (OD), a process in which forward osmosis (FO) is utilized to dilute a natural high salinity source (i.e., seawater), as a tertiary wastewater treatment process in coastal areas using a pilot scale system. The system's rejection of nitrogen and carbon species was evaluated and the specific energy demand for the process was calculated. In addition, the propensity and effects of membrane fouling were evaluated and osmotic backwashing was tested as a potential method to minimize membrane fouling. The system's rejection of nitrogen and carbon species was comparable to other tertiary treatment processes and the energy demand was found to be lower than that of other advanced membrane treatment processes. As a tertiary treatment process, OD could present many advantages including simultaneous removal of nutrients and disinfection of product water, lower energy demand relative to other membrane treatment processes, and lower costs compared to traditional processes.

https://scholarworks.calstate.edu/concern/theses/3x816q18r

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