The design and construction of animal waste and wastewater collection systems for confined swine feeding operations shall meet the following minimum standards:
(a) Gutters and trenches that do not have a constant hydraulic head against the joints or the structure, such as those designed to be free draining and are frequently flushed or scraped, shall have a watertight design. - (i) Construction shall be of air entrained concrete with a 28-day compressive strength of 4000 psi or better. The minimum thickness of any section shall be four (4) inches. All joints shall be keyed construction and sealed with a high quality elastomeric caulk. Any other materials proposed for gutter construction shall be evaluated under the provisions of Section 31 of these regulations.
- (ii) Flushing gutters shall have a minimum grade of 0.4 percent.
- (iii) Gutters shall be flushed at least every 12 hours or scraped once each 48 hours. Each gutter shall be inspected weekly and any build ups removed or freed using manual scraping or pressure washers.
- (iv) Gutters shall be cleaned and visually inspected at least annually for water tightness. Any probable leaks shall be repaired immediately.
(b) Gutters and trenches that normally retain manure and flush water and are subject to a constant hydraulic head shall be described as pull plug gutters. Any waste containment structures normally subject to hydraulic head, including pull plug gutters, shall have secondary containment with a leak collection and recovery system. - (i) Construction shall be of air entrained concrete with a 28-day compressive strength of 4000 psi or better. The minimum thickness of any section shall be four (4) inches. All joints shall be keyed construction and sealed with a high quality elastomeric caulk. All expansion joints shall have bulb type water stops. Any other materials proposed for gutter construction will be evaluated under the provisions of Section 31.
- (ii) The secondary containment shall consist of a geomembrane at least 20 mils thick installed by the manufacturer's recommendations, a geosynthetic clay liner or a compacted clay liner at least one foot thick with a permeability of 1 X 10-6 cm/sec or less. Compacted clay liners shall be constructed, tested, and certified in accordance with the provision of Section 35(d)(i)(A). The secondary containment shall be graded to the recovery system with a minimum grade of 0.4 percent.
- (iii) The secondary containment surfaces shall drain by gravity into the recovery system. The recovery pump shall have a totalizing hour meter and a high level alarm.
- (A) The amount of the liquids being recovered from the secondary containment surface shall be determined and recorded on a weekly basis. If the calculation of liquids recovered exceeds sixty (60) gallons/week/thousand square feet of confinement building, repair of the gutters and trenches must be completed within six (6) months. The permittee shall report any exceedance of this rate to the Division within seven (7) days.
- (B) If the high level alarm is activated or the recovery rate exceeds 120 gallons/week/thousand square feet of confinement building the gutters must be drained immediately and operated as free draining, daily flush type gutters until repairs are made. The permittee shall report any exceedance of this rate to the Division within 48 hours.
- (iv) Pull plug gutters shall be charged to a minimum depth of six (6) inches with fresh or recycled water before receiving animal wastes.
- (v) A minimum clearance of six (6) inches must be maintained between the top of the animal waste and the bottom of the trench cover.
- (vi) Pull plug gutters shall be drained and recharged at least every fourteen (14) days.
(c) Collection lines convey animal waste and flush water from the gutters and trenches to treatment or storage facilities. This section contains the minimum standards for the design and construction of animal waste piping and transfer systems. - (i) Collection lines shall be designed to accommodate the maximum instantaneous flows. If storm water is collected and introduced to the animal waste treatment or storage facilities, the design of the collection system and the treatment or storage system shall be adequate to accommodate the maximum instantaneous and annual precipitation rates.
- (ii) Collection line layouts shall allow isolation of individual lines for testing and cleaning.
- (iii) Pipe materials shall resist acid and alkaline solutions, organic solvents, and other animal waste constituents and environmental conditions encountered.
- (iv) Pipe materials shall be chosen and the pipeline shall be designed to withstand all trench and superimposed surface live loads with a minimum factor of safety. Rigid pipes shall have a minimum factor of safety of 1.5, and flexible pipes shall have a minimum factor of safety of 1.25.
- (v) Piping shall be tested for integrity after all trenches are backfilled. The testing results shall be certified by a Wyoming licensed engineer. Leakage tests shall be infiltration, exfiltration, or air tests. All flexible piping shall be tested for deflection. Deflection tests shall be made with a mandrel or other technology producing comparable data.
- (A) Infiltration or exfiltration shall not exceed a maximum of 200 gallons per inch diameter per mile per day (1200 liters/cm/km/day) with a minimum of two (2) feet (0.6 m) of head over the top of the pipe.
- (B) Air tests shall conform to ASTM C-828-80.
- (C) A maximum five (5) percent deflection after flexible pipe is backfilled for thirty (30) days is allowed. A mandrel of 95 percent of pipe diameter shall be used. No mechanical pulling of a mandrel is permitted.
- (vi) Potable water shall be protected according to the AWWA Manual M14, which addresses cross-connection control.
- (vii) If animal waste or waste water is pumped, the pumping station shall be designed if possible so that failure shall not result in any release. If such design is not possible, a redundant, fail safe design of the pumping station shall be required.
(d) Gravity drained lines shall be tested at least every five (5) years for leakage according to Section 33(c)(v) of these regulations. Test results shall be included in the annual report. Lines failing the leakage test shall be repaired within thirty (30) days. After repair, the integrity of the line must be verified by retesting.
(e) Pressure lines shall be tested annually for leakage according to Section 33(c)(v)(A). Test results shall be included in the annual report. Lines failing the leakage test shall be removed from service and repaired immediately. After repair, the integrity of the line must be verified by retesting.
020-20 Wyo. Code R. § 20-33