340-096-0150 Special Rules Pertaining to Composting: Unacceptable Odors (1) The department recognizes that the microbial metabolic activity in composting piles and anaerobic digestion operations causes odors, and that composting facilities cannot completely eliminate all odors. All composting facilities must be designed, constructed, and operated in manner that, to the greatest extent practicable consistent with proper facility design and operation, controls and minimizes odors that are likely to cause adverse impacts outside the boundaries of the facility. (2) The department may require a facility to prepare an Odor Minimization Plan under section (5) of this rule, and may further require the facility to modify operations and otherwise implement all reasonable and practicable measures determined necessary by the department to control and minimize adverse impacts of odors outside the boundaries of the facility. In deciding whether to require an Odor Management Plan, the department will consider the frequency, duration, strength and intensity of odors; the number and frequency of complaints; and the number of people impacted. (3) When a composting facility receives a complaint about odor, the facility must: (a) Contact the complainant within 24 hours to discuss the complaint; (b) Keep a record of the complaint; the name and telephone number of the complainant, when available; the date the complaint was received; (c) Investigate site conditions and operations to determine the extent of an odor problem; and (d) Immediately initiate procedures at the facility as appropriate to meet the performance standards under OAR 340-096-0070(4). (4) A facility must notify the department: (a) If a facility receives complaints from five or more individuals about a given event, or (b) If an odor event lasts for more than 24 hours without resolution or mitigation of the problem creating the odor event. (5) Odor Minimization Plan. If required by the department under OAR 340-096-0090 or this rule, the composting facility must develop an Odor Minimization Plan to minimize odors. The plan must include: (a) A management plan for malodorous feedstocks; (b) Procedures for receiving and recording odor complaints, immediately investigating any odor complaints to determine the cause of odor emissions, and promptly remedying any odor at the facility that does not meet the performance standards under OAR 340-096-0070(4); (c) Additional odor-minimizing measures, which may include the following: (A) Avoidance of anaerobic conditions in processes that are designed for aerobic composting; (B) Use of mixing for favorable composting conditions; (C) Formation of windrow or other composting piles into a size and shape favorable to minimizing odors; (D) Use of end-product compost as cover to act as a filter during early stages of composting; (E) Specification of a readily available supply of bulking agents, additives or odor control agents; (F) Procedures for avoiding delay in processing and managing feedstocks during all weather conditions; and (G) Methods for taking into consideration the following factors prior to turning or moving composting material: (i) Time of day; (ii) Wind direction; (iii) Percent moisture; (iv) Estimated odor potential; and (v) Degree of maturity. Statutory/Other Authority: ORS 459.045, 459A.025 & 468.020 Statutes/Other Implemented: ORS 459.005, 459.015 & 459.205 History: DEQ 7-2013, f. & cert. ef. 8-29-13 DEQ 6-2009, f. & cert. ef. 9-14-09