California Association of Sanitation Agencies (CASA) Director of Renewable Resource Programs, Greg Kester recently blogged about land application of biosolids and its important role in climate change and healthy soils.
What is the most successful recycling program in America? I would argue that it’s the successful recycling of biosolids back to land – returning to the soil that from which it came. Biosolids are the highly beneficial product of wastewater treatment. Solids produced in the water cleansing process are themselves treated and called biosolids when they meet federal and state requirements which allow their recycling to land. Land application has been researched for decades at virtually every land grant university in the country and the benefits well documented through myriad programs. Biosolids improve soil health through the increase of soil organic carbon, increased crop yield and biomass production, decreased need to irrigate due to their high water holding capacity, and improved soil tilth. Land application also mitigates climate change by sequestering carbon long term in the soil and reducing the use of fossil fuel-intense chemical fertilizer (almost a quarter of a gallon of fossil fuel is required to produce every pound of inorganic nitrogen). Yet, this recycling practice is curtailed in various parts of California due to restrictive county ordinances. We hope to work with those counties to revise their ordinances to allow land application while still providing sufficient safeguards so as to ensure public and environmental health.
California has enacted several laws to mitigate climate change and improve environmental and public health by 2020. The wastewater sector can help achieve all of the goals of these statutes, which include: returning to 1990 levels of carbon dioxide equivalent emissions; producing 50 % of our energy from renewable sources (by 2030); recycling 75% of the solid waste generated in the state; reducing the carbon intensity of transportation fuel by 10%; reducing short lived climate pollutants (SLCP) (including methane); and ensuring healthy soils for future generations of California farmers.
How can the wastewater sector help achieve these goals? We can help through the receipt of more organic waste for co-digestion at our plants—waste which would otherwise be destined for landfills. Through co-digestion with organics, we produce more biomethane which can be used to generate more renewable energy, be converted to low carbon transportation fuel, or be injected into pipelines. Diversion of this organic waste stream from landfills also helps meet the strategy outlined in the short lived climate pollutant reduction plan. Finally we can recycle biosolids to land to help improve soil health and simultaneously mitigate climate change. Go to the full story>