Special Rules Pertaining to Composting: Biogas, Liquid Digestate, and Leachate Collection Design and Management Requirements
(1)All composting facilities that collect biogas, liquid digestate, leachate or stormwater in engineered structures must comply with this rule.
(2)If required by the department, a person proposing to construct a new composting facility that is subject to this rule must prepare and submit to the department a Facility Design and Construction Plan, stamped by a registered professional engineer, as part of the Operations Plan approval under OAR 340-096-0090 (Special Rules Relating to Composting: Operations Plan Approval). The Plan must include site layout, biogas collection and storage system, lining and leachate collection/management system, liquid digestate collection/management system, and stormwater and process water collection and treatment facilities.
(3)If required by the department, any person subject to this rule must submit site design and engineering plans for any new facility construction such as site modifications, liners/pads, tanks and piping, closure of existing composting areas/systems, and/or other ancillary facilities.
(4)All construction subject to this rule must be performed in accordance with the approved plans and specifications, including all conditions of approval. Any amendments to those plans and specifications must be approved in writing by the department.
(5)If required by the department, prior to initiating construction, a facility subject to this rule must submit and receive written department approval of complete construction documents for the project to be constructed. The construction documents submitted must:
(a)Define the construction project team;
(b)Include construction contract documents specifying material and workmanship, and requirements to guide how the Constructor is to furnish products and execute work; and
(c)Include a Construction Quality Assurance (CQA) plan describing the measures that will be taken to monitor and ensure that the quality of materials and the work performed by the Constructor complies with project specifications and contract requirements.
(6)If required by the department, within 90 days of completing construction, a facility subject to this rule must submit to the department a Construction Certification Report, prepared by a qualified independent party, to document and certify that all required components and structures have been constructed in compliance with the permit requirements and approved design specifications. This submittal must include “as constructed” facility plans which note any changes from the original approved plans.
(7)For a facility subject to section (6) of this rule, the facility must not accept feedstocks for storage, processing or composting in newly constructed facilities or areas until the department has accepted the Construction Certification Report. If the department does not respond in writing to the Construction Certification Report within 30 days of its receipt, the facility may accept feedstock at the facility in the newly constructed facilities or areas.
(8)Protective surface requirements. If a protective surface is required by the department under OAR 340-096-0120 (Special Rules Pertaining to Composting: Groundwater Protection) for feedstock storing, mixing, grinding, or active processing areas, the surfaces must be designed to prevent release of leachate to surface water or groundwater from such areas. The surface must:
(a)Consist of at least two (2) feet of compacted soil with a hydraulic conductivity of no more than 1x10-6 cm/sec or an equivalent protection of groundwater;
(b)Be capable of resisting damage from movement of mobile operating equipment and weight of stored piles;
(c)Prevent ponding; and
(d)Direct all collected leachate, liquid digestate and stormwater to collection devices.
(9)Leachate and liquid digestate storage design must assure collection of any leachate and liquid digestate generated from areas of feedstock collection and preparation and active composting areas and convey the leachate and liquid digestate to a storage basin, tank or other containment structure that has:
(a)Adequate capacity to collect and contain the amount of leachate and liquid digestate generated. Volume calculations must be based on facility design, monthly water balance and precipitation data;
(b)A geomembrane liner or alternative design approved by the department that is equivalent to at least two (2) feet of compacted soil with a hydraulic conductivity of no more than 1x10-6 cm/sec;
(c)Secondary containment for tanks used to store leachate and liquid digestate;
(d)A monitoring system to identify releases for underground tanks; and
(e)If part of the site design, dikes or slopes designed to maintain their structural integrity under conditions of a leaking liner and capable of withstanding erosion from wave action, overfilling or precipitation.
(10)Any leachate or liquid digestate collection system subject to this rule must describe the methods the facility will use to beneficially reuse or properly dispose of all collected liquids.
(11)The department may approve alternative methods of compliance with this rule if the department determines that the proposed alternative methods will achieve the same level of protection. Proposed design alternatives to subsections (2) and (3) of this rule must be accompanied by engineered specifications for department review and approval.
Rule 340-096-0130 — Special Rules Pertaining to Composting: Biogas, Liquid Digestate, and Leachate Collection Design and Management Requirements,