Civil Engineering ETDs

Publication Date



As sources of clean fresh water diminish, there is an increasing interest in water reuse. Membrane bioreactors (MBRs) are commonly used in wastewater treatment plants, though reuse of treated wastewater for potable purposes requires more advanced treatment. Reverse osmosis (RO), a water treatment process commonly used for drinking water, provides near complete removal of all inorganic and organic constituents from water. While much research has been conducted on both treatment processes, little research has been done on how the combined processes work together in treating wastewater to high enough standards for potable water reuse. The MBR-RO treatment process was studied using a bench scale system to treat primary wastewater effluent from a large municipal wastewater treatment plant. The solids retention time (SRT) in the MBRs was adjusted to 2, 10, and 20 days for the three experiments conducted and various parameters were measured. These parameters included inorganics and organics in the water and on the RO membranes, as well as the specific flux across the RO membranes. While the concentrations of organic and inorganic constituents in the MBR permeate were similar at the different SRTs, they accumulated to different concentrations on the RO membranes, and different rates of RO specific flux decline were observed. The higher the MBR SRT, the faster the decline in RO membrane specific flux. The effectiveness of RO membrane cleaning could not be correlated to MBR SRT. Confocal microscopy revealed higher ratios of live cells to dead cells and carbohydrates to dead cells at the highest SRT, but no trend was observed.


Membrane reactors, Water--Purification--Reverse osmosis process, Sewage--Purification--Reverse osmosis process, Membrane reactors, Fouling


State of New Mexico

Document Type




Degree Name

Civil Engineering

Level of Degree


Department Name

Civil Engineering

First Advisor

Howe, Dr. Kerry

First Committee Member (Chair)

Thomson, Dr. Bruce

Second Committee Member

Schuler, Dr. Andrew