Excuse me, Dr. Christensen, but a student parked their bio-toilet experiment right here in the middle of your new Sustainable Technology Outdoor Research Center.
Don’t expect Mike Christensen to flinch at this news. He’s carved out space for this research center precisely to showcase student ideas like this one. Christensen is the associate vice president for risk management services at Sacramento State, but he’s also an environmental scientist who sees infinite possibilities where others see waste.
Christensen is the guy who Susan Holl, chairwoman of the mechanical engineering department, contacted when her students suggested recycling all the kitchen oil from Sac State eateries into biodiesel. He’s the guy who got the call when environmental studies professor Dudley Burton let it be known that he wanted to start an aquaponics research project.
Christensen saw both projects as opportunities to get students and faculty from many disciplines working together to create a more sustainable campus, and he identified a scrap of land opposite parking lot 4 that could accommodate not only biodiesel and aquaponics experiments but also student experiments such as the aforementioned bio-toilet.
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When that bio-toilet was made, Christensen said, the student was showing how to compost human waste until it was free of pathogens and could be used as fertilizer, but the composting toilet has other viable uses because of its proximity to the aquaponics greenhouse.
“We’re going to feed the fish with worms,” Christensen explained. “Well, we’re not using the composting toilet now for human waste. We’re using it just to compost (food scraps) and collect data on it. Well, the compost can be used for worm food. The worms can then be fed to the fish as kind of a whole cycle that’s addressed in this process, and the students can immediately begin to see how everything interrelates and has a potential to interrelate.”
Creating a food chain
The STORC, as Christensen affectionately calls the research center, is not a place where predictability will rule the day, so students and faculty will meet with frequent challenges.
In the case of the aquaponics research project, for instance, Burton said it’s taken a while to balance the fish waste generation with plant nutrient requirements.
“We’re not trying to move too fast on all that,” Burton said. “It’s going to take a while to get the bacteria seeded into the pumice stone.”
The waste from bluegill, sunfish and catfish are providing fertilizer for Swiss chard, lettuces, tomatoes and strawberries. As the plants process the waste, the water can be recycled and returned to the fish aquarium. Burton said students will be challenged to experiment with fish selection, food waste, plant species and more.
Aquaponics, Burton said, uses a fraction of the water used by traditional agriculture. He has created an aquaponics area in the demonstration garden at the Sacramento Food Bank in Oak Park.
“We want to develop this as a model for what can be done in Oak Park as a way to see what can be done in food deserts to improve nutrition, improve local food production and create protein on a local basis.”
Four Sacramento State students – Borannie Buth, Manmeet Minhas, Lydia Palma and Adilene Prieto – have left a lasting legacy at the Sustainable Technology Outdoor Research Center.
They created a biodiesel production system that Christensen and Holl have moved to the new research center. They’re testing it, with the goal of eventually using the system to convert the more than 200 gallons of waste cooking oil generated by Sac State each month into biodiesel fuel that could help power the tractors, lawn mowers and other biodiesel power equipment on the campus.
“Diesel power equipment currently in use at Sac State consumes approximately 276 gallons per month,” Christensen said. “At current prices, that is over $1,000 per month. The biodiesel conversion system cost roughly $5,000 to construct. The production cost of biodiesel fuel is approximately $1.25 per gallon. If the system produces only 125 gallons of biodiesel fuel per month, it will pay for itself in 16 months.”
Holl added that projects like these reduce the university’s environmental impact while also giving students a chance to solve the types of challenges they will one day face on jobs.
“Many folks see engineering people as being a little bit more isolated, not as worldly,” she said. “This is one of the ways that we like to create an interdisciplinary opportunity, so students see that they’re working for the world, that their job is to make the world better.”