Odor is the number one operational challenge that threatens sites in California. Due to the encroachment of residential and commercial properties, all sites, with the exception of a few agricultural sites, will need to explore a strategy of odor minimization. Odors are generally a nuisance, not a health risk to the community. Information on health issues is included with emissions. This page includes information on odor impact minimization, odor complaint investigations, components of odor, detection, and measurement.
The human nose’s ability to smell makes it the most sensitive detection tool available. Although, it should be remembered that sensitivity to odors is variable from one person to the next. Quantifying the amount of odor that constitutes an objectionable amount is virtually impossible due to the wide variation in how people perceive odors as well as the typically transient nature of odors. Some possible detection tools are the scentometer, jerome meter and field olfactory meter. Odor panels have also been used to analyze odor samples.
It is a violation for odor to cause a nuisance. Additionally, all compostable material handling activities must be done in a manner that minimizes odors and in accordance with the Odor Impact Minimization Plan (OIMP). For CalRecycle-promulgated regulations, "nuisance" includes anything which is injurious to human health or is indecent or offensive to the senses and interferes with the comfortable enjoyment of life or property, and affects at the same time an entire community, neighborhood, household or any considerable number of persons although the extent of annoyance or damage inflicted upon an individual may be unequal and which occurs as a result of the storage, removal, transport, processing or disposal of solid waste. The CalRecycle minimum standard (14 CCR 17867(a)(2)) for odor requires that "All handling activities shall be conducted in a manner that minimizes vectors, odor impacts, litter, hazards, nuisances, and noise impacts; and minimizes human contact with, inhalation, ingestion, and transportation of dust, particulates, and pathogenic organisms." Requirements for and examples of OIMPs are provided below. Local jurisdictions may have their own odor or nuisiance ordinances.
Odors from composting can generate problematic odors including ammonia, hydrogen sulfide (the smell of rotten eggs). There are characteristic components of odors from composting.
Odor Complaint Investigations
Investigation of odor complaints and identification of the odor source are the crucial first steps in resolving an odor occurrence.
Odor Impact Minimization Plan (OIMP)
The OIMP is an aggressive operational plan devised by the operator to prevent odors from occurring and to plan in advance the complaint investigation procedures and mitigation measures that should be taken if odors do occur. All composting sites, with the exception of some agricultural sites, are required to have a an odor impact minimization plan.
Comprehensive Compost Odor Response Report (C-CORP)
The C-CORP Report contains compost process information, best management practices and other solutions to odor problems at compostable materials handling sites.
1998-99 Compost Odor Management Initiative
The 1998-99 compost odor management initiative provides historical information on recommendations for handling odor nuisances atcomposting operations in response to Senate Bill 675 (Costa, Chapter 788, Statutes of 1997).