OAR 340-043-0170: Guidelines for the Design, Construction, Operation and Closure of Chemical Mining Operations: Land Disposal of Wastewater

(1) To qualify for land disposal of excess wastewater, the permit applicant shall demonstrate to the Department that the process has been designed to minimize the amount of excess wastewater that is produced, through use of water-efficient processes, wastewater treatment and reuse, and reduction by natural evaporation. Excess wastewater that must be released shall be treated and disposed of to land under the conditions specified in the permit. (2) A disposal plan shall be submitted as part of the permit application that, at a minimum, includes: (a) Wastewater quantity and quality characterization; (b) Soils characterization and suitability analysis; (c) Drainage and run-off characteristics of the site relative to land application of wastewater; (d) Proximity of the disposal site to groundwater and surface water and potential impact; (e) Wastewater application schedule and water balance; (f) Disposal site assimilative capacity determination; (g) Soils, surface water and groundwater monitoring plan; (h) Potential impact on wildlife or sensitive plant species. (3) The Department will evaluate the disposal plan and set site-specific permit conditions for the wastewater discharge.