Section 250-RICR-150-10-3.28 - Appendix 1 - Processes to Significantly Reduce PathogensA. Aerobic Digestion. The process is conducted by agitating sludge with air or oxygen to maintain aerobic conditions at residence times ranging from 60 days at 15°C to 40 days at 20°C.B. Air Drying. Sludge is dried on sand beds or on paved or unpaved basins. A minimum of three months is needed, two months of which temperatures average on a daily basis above 0°C.C. Anaerobic Digestion. The process is conducted in the absence of air at resi-dence times ranging from 60 days at 20°C to 15 days at 35°C to 55°C.D. Composting. Either the within-vessel, static aerated pile or windrow composting method is used to maintain the temperature of the sludge at 40°C or higher for 5 days. For 4 hours during the 5-day period, the temperature in the compost pile exceeds 55°C. E. Lime Stabilization. Sufficient lime is added to the sludge to produce a pH of 12 after 2 hours of contact. pH measurements shall be performed at 25°C or corrected to 25°C. F. Other Methods. Other methods or operating conditions, if accepted by the U.S. Environmental Protection Agency, may be used if pathogens are reduced to an extent equivalent to the reduction achieved by any of the above methods.250 R.I. Code R. 250-RICR-150-10-3.28