R 323.2234 Slow rate land treatment.

Rule 2234. (1) Slow rate land treatment is the application of wastewater to a vegetated land surface with the applied wastewater being treated as it flows through the plant and soil matrix. A portion of the flow is expected to percolate to the groundwater while the remainder is utilized by plants or lost through evaporation. A facility utilizing a slow rate system for the land treatment of wastewater shall design and construct the system under this rule. (2) The wastewater loading volume shall be designed so that the wastewater will be absorbed and held within the effective rooting zone of the vegetative cover established on the site receiving the wastewater. (3) The daily application rate, in inches per day of the wastewater, shall not exceed the permeability as determined by R 323.2233(2)(a)(v) multiplied by 24. (4) The header ditch drainage and the grading of the furrows, where utilized, shall be tested for equal liquid distribution before seeding. (5) The system shall be seeded with a mixture of perennial vegetative cover, which are grasses such as reed canary grass, tall fescue, and orchard grass, alone or in combination with legumes, such as clover, alfalfa, and birdsfoot trefoil, suited to the climate and the soil moisture conditions created as a result of the application of wastewater in accordance with the designed loading cycle. The department may approve alternative vegetative cover on a case-by- case basis, but may impose restrictions based upon the characteristics of the proposed alternative. (6) All furrow side slopes, where present, shall be designed and constructed to allow for periodic maintenance and or mechanical harvesting of vegetative cover. (7) The depth of the furrows of a ridge and furrow system, when utilized, shall be adequate to contain the highest proposed furrow stream. The furrow stream is the volume, in gallons per unit time, usually per minute, of wastewater discharged into the furrow.