This is a learned response to Mr. Mayo in the Chatham Chatlist edition # 4141. I am a composting expert, having founded the industry in North Carolina ca. 1974. Biosolids are sludges, by another name. What you mean is the waste product of municipal wastewater treatment plants. The recent term was invented sometime in the last few decades. I don’t recognize Mr. Jenkins name, but I am sure that he is a fine fellow.