Section 250-RICR-150-10-3.29 - Appendix 2 - Processes to Further Reduce PathogensA. Composting. Using either the within-vessel composting method or the static aerated pile composting method, the temperature of the sewage sludge is maintained at 55°C or greater for three days. Using the windrow composting method, the temperature of the sewage sludge is maintained at 55°C or greater for at least 15 days. During the period when the compost is maintained at 55°C or greater, there shall be a minimum of five turnings of the windrow.B. Heat Drying. Sewage sludge is dried by direct or indirect contact with hot gases to reduce the moisture content of the sewage sludge to 10 percent or lower. Either the temperature of the sewage sludge particles exceed 80°C or the wet bulb temperature of the gas in contact with the sludge at the point where it leaves the dryer exceeds 80°C.C. Heat Treatment. Liquid sludge is heated to a temperature of 180°C or higher for 30 minutes. D. Thermophilic Aerobic Digestion. Liquid sludge is agitated with air or oxygen to maintain aerobic conditions at residence times of 10 days at 55°C to 60°C.E. Beta Ray Irradiation. Sludge is irradiated with beta rays from an accelerator at dosages of at least 1.0 megarad at room temperature (ca. 20°C).F. Gamma Ray Irradiation. Sludge is irradiated with gamma rays from certain isotopes, such as Cobalt 60 and Cesium 137 at room temperature (ca. 20°C). G. Pasteurization. Sludge is maintained at a minimum temperature of 70°C for at least 30 minutes. H. Other Methods. Other methods or operating conditions if acceptable 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-150-10-3.29