Efficiencies in Waste Processing

Processing of solid waste involves quantification of the performance of separation devices. The concept of efficiency is difficult to define. The literature frequently makes use of recovery, but that can be very misleading, since purity is left unaccounted for. Ideally, one should like to account for both purity and recovery in a single term. This becomes more cumbersome when one is dealing with n-way separators rather than restricting the discussion to binary separators. Criteria for an efficiency expression are discussed, current efficiency parameterization practices are outlined, and a current definition that satisfies all of the common criteria for an efficiency expression is presented. An alternative method of producing the efficiency distribution is developed. The efficiency expression is discussed on the basis of results from the new implementation, and the implications are presented. The use of the efficiency distributions to define the “robustness,” or resistance to perturbation, of the unit in operation is discussed.