In order to solve an actual problem existing in Cuba in swine waste treatment plants, a system called 'high-rate-modified-anaerobic-process' (HRAMP) was developed. It consisted mainly of the incorporation of a liquid anaerobic reactor (LAR) into the existing plants to treat the supernatant liquid coming from the sedimentation unit In this work, the main results were obtained over a 3-year period A laboratory-scale comparison with conventional processes was made which showed that HRAMP was 16-50% more efficient than conventional plants. This better operation was due to the inoculum, that would be added daily to LAR from the anaerobic sludge-digester that already exists in piggery waste treatment plants.