Last year, a group of agronomists and soil scientists toured several locations in San Antonio that highlight some new programs and services. Composting can help reduce waste and solve landfill problems. Urban agriculture can reduce the amounts of food deserts and make good use of open urban land. Let’s look at what San Antonio is doing.
San Antonio is one of the few cities that provides a separate green cart just for organic material. All San Antonio residents can receive a green organics recycling cart as part of the new Pay As You Throw (PAYT) program. “If a worm can’t eat it, it doesn’t go in the cart” is their moto and direction to customers.
The city encourages new enterprises that grow food inside city limits. These include a warehouse that grows leafy greens in hydroponic containers. It also includes rooftop gardens and urban farms in open locations suited to these endeavors.
The Garden-ville Texas Disposal Composting SARA Facility in Converse, TX, has active compost piles. This project is a joint effort between public and private programs. As you can see in the photos, steam was rising from the piles. This is because soil microbes and other organisms create a lot of heat while “digesting” the organic waste and turning it into valuable compost.
Items that the city collects in special bins are: yard wastes (leaves, grass, shrub and tree trimmings) and kitchen wastes (food scraps and food-soiled paper like used napkins, paper plates, and pizza boxes.)
The facility creates large piles and rows of mixed and ground dry waste. They also add in biosolids. It’s important for piles to reach high temperatures, which kills off the bad microbes and leaves the good ones.
They test weekly for chemical, physical, and biological components. They also look for pathogens, heavy metals to make sure the products can be reused. They test temperature controls within maturing piles to verify safety and the organic makeup. Most compost bears little resemblance to the food scraps that were the original raw materials! They are usually about 50% organic matter and contain enough organic nitrogen to maintain high mineral nutrition for plant growth.
Depending on the source of raw materials such as residential dry waste and mineral supplements, the compost is bagged up to be used to improve garden soils in backyards for vegetables. It is tested to have the highest standards of US Composting Council Seal of Testing Assurance (STA) certification. If the raw materials include higher amounts of municipal biosolids or gravel in the mix, the finished compost will be used instead for redevelopment and maintenance of public areas such highway borders and municipal parks.
The SARA facility is an excellent example of a public-private partnership in San Antonio is reducing material sent to landfills by 60%. That’s their goal for this year! Diverting material to composting facilities is critical to the sustainability of waste disposal in the metropolitan area. The EPA has estimated that the landfills that the city depends on may be full without these composting and recycling projects in 70 years.
Not only does the SARA program provide employment, but it is another way to recycle valuable nutrients and keep materials out of landfills.
The compost from this facility is used by urban gardeners. It has also been used by the city in downtown districts to redevelop open space and green corridors along city highways.
Answered by Maxine J. Levin, University of Maryland and Jeffrey Howard, Wayne State University
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