Abstract: An inexpensive portable ultra-filtration system for concentrating industrial waste fluids such as cutting coolant. The system is adapted for convenient use with standard storage containers. It is lightweight, portable, and reliable, and processes waste fluids in conformance with most local environmental regulations. Its low cost makes it ideal for small volume applications. The system operates by continuously recycling the waste fluid through a cartridge prefilter and then a carriage ultra-filter. It can process a fifty-five gallon drum of contaminated coolant to yield fifty gallons of clear permeate and only five gallons of concentrated contaminated mixture in about twenty-four hours. The clear permeate can be directly sewered in most locales. An inlet pipe may be used to keep the point of waste fluid intake above most of the heavy contaminants such as sludge, thereby lengthening the operating life of the filters.