Improving Water Systems in Rural California by Shiyun Yao

In 2012, Governor Brown made California the first state in the US to legally recognize “the human right to water” when he signed AB 685 that acknowledges that “every human being has the right to safe, clean, affordable, and accessible water adequate for human consumption, cooking, and sanitary purposes [1].”  However, as of 2014, over 1 million Californians still do not have safe drinking water either because their publicly supplied water contains constituents over the regulated Maximum Contaminant Level (MCL) or because they rely on insecure private wells that receive no treatment at all [2].  Improving the availability to clean drinking water enhances livelihood security, reduces health risks and promotes pro-poor economic growth [3].  The objective of this project is to further develop and test a robust, sustainable, and low cost UV based treatment system developed at UC, Davis specifically intended to meet the drinking water needs of rural communities.

Figure 1: a) Solar panel used for the system; b) UV treatment system placed inside a storage container; c) solar control panel used to connect panel to battery.

From January to June of this year we had tested our drinking water disinfection system (Figure 1.) in the lab and planned to focus on field testing this summer.  As the first location for this field testing, we decided to tag along with the bi-annual trip organized by the International Veterinary Outreach (IVO) organization and Bones Pet Rescue to the city of Covelo, CA in the Round Valley Indian Reservation.  These groups run a weekend long free spay and neuter clinic at the Covelo Recreation Center shown in Figure 2.  Laura, one of our grant recipients had volunteered with this organization in the past and knew that the facility has its own insecure groundwater supply (i.e. the water is not chlorinated). We drove to Covelo on the evening of August 6^th then we camped two nights in the areas behind the Covelo Recreation Center.  In the morning, we woke up with the vet students at around 7 o’clock.  Their operation started at 8 o’clock.  To accommodate their schedule, we laid out solar panel and battery in the morning to achieve peak sunlight conditions so that we could start our UV system treatment in the afternoon.  The clinic operation conditions and the surrounding of our campground are shown in Figure 3.

We collected groundwater on both days of August 7^th and 8^th to
establish a background of water quality that we could then use to assess whether UV would be a viable drinking water treatment solution for this area.  Then on Sunday, August 8th, we did additional testing to spike the non-pathogenic E. coli to assess the disinfection performance of our system.  The testing with E. coli was performed using a small water basin we brought with us so that we could contain the water for disinfection after we were done performing our experiments (we used bleach).  Our test performance on site is shown in Figure 4. We chose to do this testing on Sunday so we could rush the samples back that night to Davis.  

Figure 2. Round Valley Indian Reservation Recreation Center: a) is the main building of the Covelo Community Center; b) is the water storage tank outside of the Covelo Community Center; c) main water source of collected samples from the private well and the tap is surrounded by mints.

Testing of the background water revealed that the drinking water source is contaminated with total coliform and E. coli, 98.5 MPN/100 mL and 46.83 MPN/100 mL, respectfully.  To confirm this result, this testing was repeated using a separate set of samples that they collected and shipped to us one week later.  The total coliform count indicates that the water has been exposed to plants or livestock waste material.  Coliforms are found in most fresh water sources, even natural spring water, and are of low risk to most people.  However, fecal coliforms, particularly E. coli, indicate that there are mammal or bird feces in the water source.  The EPA’s Maximum Contaminate Level Goal (a recommended level for public safety) for E. coli is zero MPN/100 mL [4].  We were sure to inform the managers of the facility after we finished processing the samples.

Figure 3. a) Treated animals are placed in cages after recovery; b) Operation tables at the Recreation Center; c) Camping sites near the Recreation Center. (Source: www.facebook.com/internationalveterinaryoutreach)

Testing of our disinfection system revealed that it was able to

sufficiently treat the background water and performed well 

at disinfecting higher doses of nonpathogenic E. coli during our testing on Sunday.  Because of this, we hope that we might be able to install our system at the site for a longer period of time to assess long-term performance, ease of use and maintenance needs.  In the meantime, for our next round of testing we plan to bring our system to a campsite and test the performance of the system using groundwater and surface water.

Figure 4. Performing the tests with hardness kits

References:

[1] AB 685, ch. 524, 2012 Cal. Stat. 91 (Codified at Cal. Water Code § 106.3)

[2] Community Water Center <www.communitywatercenter.org> Accessed Feb. 8, 2016.

[3]  Soussan, J., et al. (2007). “Linking Poverty Reduction and Water Management.” Stockholm International Water Institute (SIWI), Sweden.

[4] US EPA. (2016). “Table of Regulated Drinking Water Contaminats.” <https://www.epa.gov/ground-water-and-drinking-water> Accessed Sept. 1, 2016