Steam Condensate Reclamation - Feasibility Study

This mini-grant will be used to fund a portion of a larger feasibility study regarding the use of reclaimed water on campus. With support from UW-Facilities and the department of Civil & Environmental Engineering, I have spent the last eight months determining the feasibility of reclaiming steam condensate from the campus utility tunnel system. The University has 8.5 miles of subterranean tunnels that serve every building with steam, chilled water, electricity, compressed air, and IT cables. The tunnels have a drain system that collects and conveys the water that is generated as condensate from the steam pipes (formed through humidity or via leaks) as well as groundwater that infiltrates the utility tunnels. Currently, the water is collected through a pipe system and is discharged into the sewer system or the SPU storm conveyance system. Through targeted renovations, it may be possible to reclaim a portion of this water and use it for various services including irrigation, cooling tower, dust control, and, notably, as fill water for Drumheller Fountain.

The use of this water would have several sustainability benefits for the University as well as major policy implications. The University would decrease its water use, sewer loading, and waste discharge into Lake Washington – reducing carbon emissions, CSO contributions, and pollutant loading into local water bodies. To my knowledge, groundwater has not been used as a reclaimable water source. Groundwater collection is subject to water rights permitting, but managing incidental groundwater collection is the responsibility of the land owner. Therefore, the groundwater infiltrating the utility tunnels would be considered incidental; in theory, it could be reclaimed and repurposed, which would be unprecedented.

The overall feasibility study is investigating the use of this reclaimed water for Drumheller Fountain. Over the course of this study, I have evaluated the existing Fountain and tunnel infrastructure, determined the local hydrology and annual water table levels, identified city and state codes that could govern the use of this water, detailed treatment requirements, presented several construction options, detailed the financial and environmental benefits of the renovation, and drafted an education & outreach plan. In addition, I have been managing a longitudinal study on the water quality of Drumheller Fountain – measuring weakly pH, conductivity, nutrient concentration, algae content, turbidity, and presence of Daphnia (a small crustacean that is indicative of mesotrophic and eutrophic water bodies). This research has been supported in-kind by the Lakes Lab in the CEE department. With the water quality data from Drumheller, I will be estimating the possible impacts of adding the reclaimed water to the Fountain. I would be happy to share this document with the Campus Sustainability Fund once completed.

One of the last stages of this feasibility study will be to analytically determine the chemical composition of the reclaimed water. We have preliminary data on the chemical additives that the Power Plant puts into the steam system (non-toxic polymers to prevent pipe scaling and microbial growth), but we need to know the minerals present in the groundwater. I will be collecting a one-liter sample of the drain water during the week of April 22^nd – 26^th. We would like to analyze this sample collected from the underdrain system for the following elements: arsenic, barium, chromium, lead, copper, cadmium, mercury, nickel, and iron. We plan on running the samples on the Inductively-coupled mass spectrometer (ICP-MS) owned and operated by the CEE department. The Lakes Lab has made several in-kind financial contributions to this project (materials, equipment, technical support, etc.), but I would like to use my own funding for the use of the ICP-MS. The feasibility of using this water is dependent on the chemical composition, and the treatment system will be designed based on the relative concentrations of these heavy metals (if they are present).

There are four financial components for this research: the cost of acquiring a standard for the ICP-MS (a sample with known concentrations of elements), several centrifuge tubes, the rental time for the ICP-MS, and staff time for operating the machine. I am also requesting a small contingency (~10%) as a safety factor for additional equipment, time overruns, and other unexpected costs. All unused funds will be returned to the CSF. Through conversations with the CEE administration, the best method for using these funds would be “option 1” noted in the AARF form – charging our expenses against a CSF-assigned PCA code. Please see the AARF form for the CEE budget code. In total, I am requesting $400, which has been itemized on the attached budget sheet.

The sample analysis will commence upon approval by the CSF. I am targeting a completion of this feasibility study by the end of May (before my graduation). My feasibility study will be presented to UW Facilities, the CEE department, the UW Green Building Subcommittee, and other entities that are determined applicable.  I would gladly present this effort to CSF as well. For future student involvement, I plan on involving a junior-level CEE student to continue communication with UW Facilities. The education and outreach components of this funded project will coincide with the section included in the overall feasibility study. The portion of this project funded by CSF will not have any additional components after the one-time analysis; there will be no ongoing costs for maintenance or support.

Although research projects are usually not supported financially by the CSF, I believe this project is an exemption. If it can be shown that the groundwater and condensate mixture is reclaimable, there will be far-reaching impacts for the University and for state-wide water policy. The University could retrofit the underdrain system to collect the water rather than discharge it, using the water for irrigation, an auxiliary source for Drumheller, or a whole host of other non-potable options. Given the short timeline of this project, I have elected to apply to the Campus Sustainability Fund rather than an R&D program because I believe this project supports the requirements, preferences, and overall mission of the CSF.

Thank you for your consideration,

Alex Ratcliff