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San Luis Obispo County, California


Land Application of Biosolids Ordinance

San Luis Obispo County has developed a permanent ordinance to establish regulations for the land application of biosolids (and composted biosolids). An interim ordinance has been in place since 2006. The proposed ordinance defines biosolids and composted biosolids:

Biosolids: Also known as treated sewage sludge, are the solid, semi-solid or liquid residues generated during the treatment of sewage by a municipal wastewater treatment plant. Biosolids and composted biosolids land applied at five (5) or more cubic yards per project are regulated by this ordinance and shall obtain a use permit from the Department prior to application. For the purposes of this ordinance, septage is not considered biosolids, and cannot be land applied in the County.

Composted Biosolids: This is the process in which biosolids are mixed with organic waste material which then decomposes in the presence of oxygen through the action of bacteria and other microorganisms (e.g., dewatered biosolids are mixed with woodchips, or green waste vegetation that act as a bulking agent by absorbing water and increasing the porosity of the compost mixture, which is then composted for several weeks). Bulk Form Composted Biosolids are composted biosolids provided by a generator or preparer in bulk form, meaning the material is not provided in a package, bag or container. Bulk form composted biosolids are normally provided by the truckload. Biosolids or composted biosolids sold in stores in bags or other containers are not regulated by this ordinance.

The proposed ordinance, if adopted will amend Section 8.13 of the County Code and replace the existing interim ordinance with this permanent ordinance. The interim ordinance is effective until March 31, 2018. Adoption of the ordinance requires the preparation and certification of an Environmental Impact Report (EIR).

The Environmental Impact Report process begins with the Notice of Preparation (NOP). The NOP describes the proposed ordinance and identifies the environmental impacts that will be studied in the EIR. Here is a copy of that NOP. Comments on the scope of the EIR can be submitted to the Department by December 18, 2015. Please send your comments to the Department's Project EIR Project Manager:

James Caruso, Senior Planner
Dept of Planning and Building
976 Osos Street; Room 200
San Luis Obispo, CA 93408
or via e-mail to