In today’s advanced hi-tech machine shop, the most challenging job is to comply with stringent environmental laws with right disposal of effluent.  Grinding sludge is a particularly difficult problem. You can't dump it in your back yard.  Manufacturers of precision components constantly struggle with how to safely and efficiently dispose of grinding sludge produced during manufacturing processes.  It must be collected and processed by a waste management company or delivered to a specially designated hazardous waste site. Typically, these are very expensive options.  There is a fairly cost-efficient way to dispose this wet grinding sludge which is gaining momentum across the globe; “Briquetting.”  It is a process that compresses materials from metal grinding chip sludge into compact, easy-to-handle cylindrical blocks (briquettes).  When briquetting is applied to grinding sludge, a significant amount of oil can be recovered and recycled, as well. An article from TES explains it in details.  From Onlinetes.com