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The BAC Yard (Bioconversion and Agricultural Collaborative)
=== Overview === The BAC Yard at California State University Sacramento was a project space designed to serve as the primary composting site for organic waste produced by fallen tree debris and grass clippings. In collaboration with the all Student Body organization on campus, an organic gardening space was designated on site to from what we now know as the agricultural component. Since its development, the site has incorporated a renewable energy component as well as bring an aquaponic system online to demonstrate the technology as well as reduce the amount of water being used on site to grow produce for the food assistance program for attending students at Sacramento State University.

Highlights of the Site

 * Aquaponics
 * Thermal (Hot) Composting
 * Vermicomposting
 * Apiculture
 * Water Impacts
 * Renewable Energy Technology
 * Education

Aquaponics
Aquaponics is a combination of aquaculture and hydroponics that utilizes a biological combination of aquatic animals, bacteria, and plants to cycle and maintain nitrogen exchange. It is a cyclical system that boasts up to 90% less water use than conventional farming methods because it cycles water through a combination of physical and biological filters. In the system running out at the BAC Yard, they utilize Large-Mouth Bass, goldfish, and crayfish as the main contributors of the ammonia production for the base nutrient supply. The water cycles through a combination of media beds that serve as a haven for bacterial colonization and the plants' root zone for nutrient uptake. This particular system implements both a flood and drain bed with expanded clay media using a bell siphon to evacuate water effectively, as well as, a deep water culture (DWC) trough that supports leafy greens on Styrofoam rafts leaving the plant roots suspended in the nutrient-rich water solution. The system is run with a single electric pump that brings the filters water from the sump tank back to the primary bass tank.

Thermal (Hot) Composting
Hot composting is an aerobic process that utilizes high levels of nitrogen and oxygen to promote bacterial breakdown of organic waste and materials. This interaction between the bacteria and the waste breakdown actually creates an exothermic reaction that produces heat; the main reason why this process is called "hot" composting. (http://compost.css.cornell.edu/physics.html)

Vermicomposting
The BAC Yard also implements the use of vermicomposting to break down the majority of the food scraps on campus that are collected from the campus eateries and dining commons from the residential halls as part of the waste diversion program under sustainability. This is used to obtain worm castings or vermicast, which is a valuable organic fertilizer. This commodity helps increase the value of what would have been considered waste and serves as an example for students participating in the living lab.

Apiculture
Apiculture is referencing the raising of bees. There are currently three-four active hives that produce honey at this specific location, while across the parking lot at the Capital Public Radio Garden, there are an additional four hives because extra space was needed. The raising of bees helps promote pollination on campus, which is an important ecosystem service in consideration to the agricultural aspect of the BAC Yard. This raises awareness for the importance of pollinators, and demonstrates the opportunity for students and staff to learn more about beekeeping so that the practices can be encouraged throughout the local community.

Water Impacts
Water for this site is necessary to continually run the operations onsite. Hot composting, though an excellent way to divert waste to landfills, is also a very water intensive process. Because aerobic digestion is required for the breakdown of the organic waste in the hot composting process, the material must be kept wet so that the bacteria and microbes have access to a supply of oxygen. The bio-swale hot composting is covered with a tarp during the finishing process helps reduce evaporation and insulates the compost pile to expedite the breakdown process. The organic ASI-funded garden also requires water for plant growth to supply produce for the food pantry services provided to students on campus. A mitigation strategy to reduce water on site, and to promote water-wise awareness, is the aquaponics system helping to supplement water use in the garden.

Renewable Energy Technology
To reduce the energy impact of the site, renewable energy generation has been a development over the last year at the site using a combination of different technologies. The use of photo-voltaic (PV) panel technology, vertical axis wind turbines (VAWT's), and a passive solar water heater are used to reduce power and scope 2 emissions of greenhouse gases (GHG's) and to promote renewable, decentralized power. The site uses a 24kwh lithium-ion power bank connected to the power sources to run some of the operations onsite. The plan is to eventually run the entire operation disconnected from the grid.

Education
In addition to providing a waste-diversion location and food production, the BAC Yard also represent s unique opportunity to serve as an educational opportunity for students and the outer community. There is multi-disciplinary participation from educational departments such as Family and Consumer-based Science, environmental studies, engineering, construction management, and Biological Sciences. Tours are frequently hosted on site for local elementary school classes and organizations such as the Air Resources Board (ARB).