2012 Stockholm Junior Water Prize State Winners
Since 2004, PNCWA has sponsored Stockholm Junior Water Prize (SJWP) students from Oregon and Washington to compete for the world’s most prestigious youth award for a water-related science project.
The SJWP competition is open to students in grades 9 through 12 with science projects aimed at enhancing the quality of life through the improvement of water quality, water resource management, or water and watershed treatment using a research-oriented approach.
Each state’s winner attends the U.S. competition, and the national winner travels to Stockholm, Sweden for the international competition. To date, Idaho has not fielded a competitor due to the nature of its science fair system, but ongoing efforts are underway to include Idaho students.
This year’s Oregon SJWP winner, Ajay Krishnan, also represented Oregon in the 2011 competition and continues to build upon his research into microbial fuel cells to power wastewater treatment facilities. Representing Washington is Anjani Patel, an 11th grader at Cedarcrest High School in Duval, whose research is on bioremediation of oil spills. The following excerpts from their papers indicate why they will be representing their states at the national competition in Boston, MA this June.
Optimizing the Microbial Fuel Cell-Microbial Electrolysis Cell Coupled System for Sustainable Hydrogen Gas Production, Electricity Generation, and Improved Wastewater Treatment
By Ajay Krishnan, Oregon Episcopal School in Portland, Oregon
The Microbial Fuel Cell-Microbial Electrolysis Cell coupled system (MFC-MEC system) may pose an inexpensive and effective solution to current environmental problems, as it combines two promising technologies, the MFC and the MEC, to simultaneously treat wastewater and produce electricity and hydrogen gas using anaerobic bacteria.
Both MFC’s and MEC’s, however, are not yet viable, because of their low current densities and short operational lives. This research developed an effective and novel method of optimizing the MFC-MEC system, by using graphite plate anodes coated with multi-walled carbon nanotubes (MWCT), and by varying the applied voltage in the cathode chamber of the MEC using a novel voltage regulator circuit1.
MWCT were deposited on graphite plates using the electrophoretic deposition method.Geobacter sulfurreducens, Shewanella oneidensis, and Rhodoferax ferrireducens were anaerobic bacteria that were used in the MFC-MEC system. Voltage was measured every hour using a Vernier voltage probe connected to a Logger Pro DAQ, and hydrogen gas was measured using a 40 mL gastight syringe.
At the end of experimentation, a MFC-MEC system with nanomodified graphite plate anodes produced a maximum combined power density of 0.56 W/m2 and a maximum hydrogen gas production rate of 6.5 mL/Day, compared to a baseline MFC-MEC system with a maximum power density of 0.23 W/m2 and a maximum hydrogen gas production rate of 4.5 mL/Day.
The power density and the hydrogen gas output were increased by approximately 150% and 50% respectively. Results of the applied voltage tests showed that as the applied voltage was increased, the hydrogen gas production rate increased.
With an optimal applied voltage 0.4 V, a hydrogen gas production rate of 3.3 mL/Day was achieved, with a usable excess voltage of 0.3 V. The MFC-MEC system was optimized for electricity generation and hydrogen gas production, and could produce hydrogen gas, electricity, or both based on demand.
This research showed that:
- The voltage applied to the MEC is directly proportional to the hydrogen output of the MFC-MEC system.
- The use of the novel low-cost EPD method to coat MWCT greatly improves the performances of both MFCs and MECs.
- A novel power management system capable of producing hydrogen gas, electricity, or both was developed.
- The optimized MFC-MEC system that was developed shows great potential for use in a wastewater treatment plant.
Cleaning Up Various Oil Spills Using Bioremediation
By Anjani Patel, Cedarcrest High School in Duval, WA
The idea was to determine whether the bacterial or fungal petrophile biodegraded more oil in the same amount of time. This project is a continuation of a project done in the 2010-2011 school year.
It was hypothesized that the fungal petrophile will biodegrade the oil quicker than the bacterial petrophile. There were 3 variables, and 2 options for each, and therefore, there were 8 sub-experiments making up this study.
The variables were
- type of environment (beach or ocean oil spill)
- type of petrophile (bacterial or fungal)
- the scale of the experiment (jar or Petri dish).
After data collection was complete (after 96 hours), each level in one variable was compared to the other. Linear regressions for the amount of oil (in mL) left after x amount of hours were also done for the 8 sub-experiments.
It was concluded that the environment most conducive to bioremediation was the beach oil spill in the Petri dish inoculated with the fungal petrophile (Penicillium).