Large-Scale Composting: Effective, Efficient Water Conservation Strategy for Public Works

Well-documented results attest to the power of composted nutrient-rich biosolids and organics when properly applied as a soil amendment to conserve water in many ways.

• By Tom Phillips
• Mar 15, 2016

With significant parts of the United States under water restrictions due to drought, it's only natural to ask, "How can public works/utilities conserve water in their communities?" The proven link between water conservation and composting makes the answer pretty straightforward. Converting biosolids and other solid waste into beneficial organic matter through composting, followed by proper land application, returns beneficial organisms, carbon, and nutrients to the soil for optimizing water retention and the slow release of nutrients.

What's more, composted biosolids combat the negative effects of tilling, including excessive drying of the soil and erosion. Compost makes soil more resistant to erosion by improving the soil's ability to hold moisture, outperforming conventional erosion control methods and reducing soil loss by 86 percent compared with bare soils.¹

Water Conservation Benefits of Composted Nutrient-Rich Biosolids and Organics
Well-documented results attest to the power of composted nutrient-rich biosolids and organics when properly applied as a soil amendment to conserve water in many ways, including:

• Increasing soil's water-holding capacity by up to seven times² to mitigate water loss
• Preventing fertilizer runoff that negatively affects lakes, rivers and oceans, and wildlife habitat
• Facilitating moisture dispersion by allowing water to more readily move laterally from its point of application
• Encouraging the proliferation of earthworms, whose tunneling increases water infiltration and aeration and significantly reduces need for tillage
• Greater drought resistance and more efficient water use to reduce the frequency and volume of irrigation: Plants' irrigation needs are reduced by up to 70 percent, mainly by reducing evaporation of water from exposed soil surfaces^3,4; turf grown with the application of composted soil conditioner can require up to 30 percent less water, resulting in deeper root systems that reduce deep drainage and irrigation requirements⁵; and more efficient water utilization by reducing runoff and evaporation.

Public-Private, Budget-Friendly Partnership
The typical public works budget is stretched quite thin. Municipalities that work with a private compost facility developer/operator can benefit greatly from the economies of scale offered by an established, experienced partner. Municipalities that are serious about water conservation should think about working with a proven partner that can reduce investment and risk by providing full project accountability for an economically and environmentally sustainable solution. A community-friendly composting program can help municipalities substantially reduce or eliminate their current disposal costs in addition to turning their waste streams into a beneficial resource that is guaranteed Class A-compliant material and can be used for landscaping, enhancing crop production, enriching topsoil and mitigating erosion and run-off.

Click here for an easy-to-share infographic that summarizes how composting supports water conservation.

References
1. University of Georgia Extension (2009), Benefits to Using Compost for Erosion Control
2. San Diego County Water Smart (2015). Improve Soil and Conserve Water with Compost
3. Abu-Awwad, A.M. (1998). Effect of mulch and irrigation water amounts on soil evaporation and transportation. J. Agron. Crop Sci. 181:55-59.1.
4. Abu-Awwad, A.M. (1999). Irrigation water management for efficient use in mulched onion. J. Agron. Crop Sci. 183:1-7.
5. U.S. EPA (1997). Innovative uses of compost. Erosion Control, Turf Remediation, and Landscaping.