2014 Progress Report: Contaminant Removal Using Membrane Distillation for Sustainable Drinking Water TreatmentEPA Grant Number: R835333
Title: Contaminant Removal Using Membrane Distillation for Sustainable Drinking Water Treatment
Investigators: Childress, Amy E , Kolodziej, Edward P. , Park, Chanwoo
Institution: University of Nevada - Reno
Current Institution: University of Southern California
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2013 through February 15, 2017
Project Period Covered by this Report: July 1, 2013 through June 30,2014
Project Amount: $499,743
RFA: Research and Demonstration of Innovative Drinking Water Treatment Technologies in Small Systems (2011) RFA Text | Recipients Lists
Research Category: Drinking Water , Water
The main objectives of the investigation are to characterize the range of drinking water contaminants and contaminant classes that can be removed by membrane distillation (MD) and to develop and test a small-scale pilot MD system that operates using waste heat to perform field testing at small water treatment systems. The steps toward achieving the goals of the proposed research are to: perform bench-scale testing of MD to evaluate membrane performance for spiked feed waters and to determine waste heat requirements (temperature, thermal power, constancy, and period of supply); evaluate a range of potential small system test sites and select at least two sites co-located or in proximity with identified waste heat sources; design and construct a modular small pilot-scale MD system with heat exchanger; and test the small pilot system on existing source water as well as a side-stream of the source water spiked with contaminants.
Project progress to date is on track with the project objectives for the period. The broad spectrum contaminant removal evaluation with ions and metal contaminants has been completed and volatile and semi-volatile contaminants testing is underway with the nitrosamines and volatiles on the bench-scale MD system. Pharmaceutical and personal care products (PPCPs) testing also is planned. Modifications to replace the flexible plastic tubing with stainless steel tubing to minimize sorptive losses are underway with the bench-scale system. The variability of the waste heat source also demonstrates further need for process control. Efforts are underway on the design and implementation of a control system for moderating the heat delivered from the waste heat source to the feed water such that a stable temperature is supplied to the MD membrane module.
Analysis of volatile and semi-volatile contaminant removal will continue with the bench-scale MD system. The previously proposed site for initial system fabrication and testing was unfortunately cancelled due to unforeseen issues – a boiler in the main heat plant at the University of Nevada, Reno, required significant maintenance, and as such, the team was asked to find an alternative location for the system. A smaller boiler system was identified on campus that supplies heat for the Lombardi Recreation Center swimming pool and HVAC systems. Because this site is on campus, it provided an opportunity for the pilot system to be implemented in a field setting while maintaining a high level of monitoring, and thus was selected as the first field site.
Additional field sites have been evaluated in the Tahoe Reno Industrial Center in McCarran, Nevada (approximately 10 miles east of Reno, Nevada), and the JamesHardie Building Products facility is under consideration for the next field installment. The facility produces fiber cement siding and backerboard, and has several process streams available for treatment. The waste heat source will be an autoclave sump that fluctuates between 70 – 100°C. In addition to this, sites outside of Northern Nevada also are being evaluated as potential field sites, with one being on campus at the University of Southern California.