Grantee Research Project Results
Final Report: Design, Optimize and Evaluate a System for Pond Water/Grey Water/Rainwater and Wastewater Sources to Provide Drinking Water Quality by Various Solar Distillation Techniques
EPA Grant Number: SU835309Title: Design, Optimize and Evaluate a System for Pond Water/Grey Water/Rainwater and Wastewater Sources to Provide Drinking Water Quality by Various Solar Distillation Techniques
Investigators: Lucas, Frank , Laznik, Abraham , Jacobson, Alyssa , Wuyke, Gabriella , DeMarco, Jackie , Villaverde, Sonia
Institution: Lynn University
EPA Project Officer: Hahn, Intaek
Phase: I
Project Period: August 15, 2012 through August 14, 2013
Project Amount: $15,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2012) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Air Quality , P3 Challenge Area - Safe and Sustainable Water Resources , P3 Awards , Sustainable and Healthy Communities
Objective:
Potable water is now becoming a precious commodity. Not only has climate change affected the location of drinking water but over population and urban expansion has diminished ground water and river supplies. Examples of this problem are everywhere, the Colorado River, San Joaquin Delta basin, and Florida aquifer. Current municipal designs for water availability use pumping underground aquifers, surface reservoirs or rivers to provide potable water to the population. The end user consume potable water for a number of uses – drinking water, wash & shower water, laundry water, coolant water for large air conditioning systems and wash water for industrial processes. This “Used” water is then collected as “waste water” a combination of Black water, grey water and potable water in the municipal sewer system and waste treatment plants. The most advanced municipal systems split off a fraction of the 99.99% water for re‐use as “NPR or Not Potable Reuse”. Can waste water, grey water, rainwater and pond water be processed by solar distillation to provide drinking water and NPR.
Approach: The study uses a solar distillation apparatus (patent # 4495034) for treatment of pond water to recover bacterial and fungal free water. This bactericidal benefit was unexpected and provides the opportunity to treat grey water, waste water and rainwater as additional sources. Several drinking water parameters are measured. The temperature of the solar still reaches pasteurization levels of greater than 130 F degrees. Processed water is collected and tested in the laboratory. Yields are measured and averaged 250 ml per day for 1.5 square feet of reservoir surface area and three square feet of condensing area. Based on the pilot data, the grant application goal is 50 gallons/day/person as a continuation of this preliminary work to improve the process yields and evaluate other designs. The improvements will be in two areas. The proof of principle design is the baseline. The design changes are the following: use vacuum to move the water vapor to the condenser, surface area modifications optimization, the use of auxiliary solar hot water heaters to pre heat the waste water by parabolic reflectors to achieve water temperatures in excess of 170 degrees F. The condenser design will study surface area improvements and maximize cooling of the condenser. Coarse filtration and storage methods for 30 day shelf life will be assessed.
Summary/Accomplishments (Outputs/Outcomes):
The use of a better condenser (original 3 sq.ft. to 6 sq. ft. now) and more consistent heat in the reservoir has doubled the yield from around 200 ml to around 500 ml per day (1.5 sq ft. @ 80 to 120 degrees ½ gal. volume capacity to 1.5 sq. ft. @ 80 to 140 degrees 4 gal. volume capacity). This reduces the area needed in a family home to 563 sq, ft. of reservoir space or the roof space of a 22 ft. x 25 ft. home to provide the daily yield to 50 gallons high purity water. The cost of the still was reduced by using available plastic ware instead of custom sheet metal fabrication. A hot water heater system was fabricated from 20 ft. x 3/8” copper tubing mounted on copper sheet metal and a glass cover, two types of pumps were tested, first, a Coleman R3603 tubing peristaltic pump with a battery/ inverter and a 45 watt solar panel electrical system and second, a solar powered fountain pump. A recirculation loop was used for incubation with bacterial kills and an Aurdino-Uno was built and programmed to measure Lux, temperature, volts and amps to monitor bacterial kill/time requirements. The Fresnel lens focal length was 9 inches and capable of producing temperatures of 230 degrees. A stand was included for the proper angle to the sun and had a swivel base to manually sun track which turned out to be a necessary function to maximize yields.
Water quality testing shows that bacteria and yeast can be neutralized with an incubation period of 3 hrs at 140 degrees when the starting material is less than a million organisms per ml and preferably 100,000. A higher temperature of 160 degrees will reduce the incubation period to 2 hours.
Fertilizer removal from the polluted water (pond, stream) was not detected after processing through the system. Starting levels were the manufacturers recommend application levels.
Soaps and Detergents (triton X100 and tween 80) were used in spiking studies at .1% levels and after treatment in the system were not detected in the product.
Testing for the herbicide 2,4 D in ground water is in progress and will continue after the grant period as student class projects.
Types of water that were tested are pond water, roof cistern water and dishwater grey water. Testing against Zephyrhills bottled water shows comparable results to it for rainwater/roof, pond water and grey water.
Conclusions:
The group was pleased with the progress made to characterize the performance of the system and feel the potential application to provide clean water with pollution prevalent and the cost of R/O or other methods more expensive than just letting the sun do it.
There are two areas that need additional developmental work. The hot water system using the Fresnel lens has never achieved its potential as a quick and efficient heating tool. The maximum temperature achieved in the testing was 232 F degrees. This was not constant, however, since the sun’s movement did not allow a prolonged exposure to the same site on the tubing surface. The sun’s movement was in two axes, both across the sky and in an arc so the focal spot was moving across and down. Typical temperatures were around 155 F degrees.
Supplemental Keywords:
potable water, grey water/rainwater recovery, drinking water, home sized integrated system, Bermuda‐Caribbean cistern system, solar distillation, cascade filtrationRelevant Websites:
Puerto Rico Aqueduct and Sewer Authority (PRASA) Exit
2014 Acueductospr.com - ¡Bienvenidos! Exit
https://www.epa.gov/compliance/resources/cases/civil/cwa/prasa.html
PRASA to Pay $1 Million Fine and Fund Drinking Water Improvements in Low-Income Communities; U.S. Reaches Agreement with Puerto Rico Aqueduct and Sewer Authority to End Illegal Discharges of Raw Sewage
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.