Original sentence: One method, that has been successful, is known as "humanure" where the material is composted with kitchen refuse and high-carbon materials such as yard waste, heated through biological activity and kept for an optimal period of time whereby the pathogens are destroyed
Edited sentence: One method that has been successful is known as "humanure" where the material is composted with kitchen refuse and high-carbon materials such as yard waste, heated through biological activity and kept for an optimal period of time whereby the pathogens are destroyed