A New Processing System for the Production of Improved Refuse Derived Fuel and Recyclables from Municipal Solid Waste

The following are the questions and comments on the paper. (a) An energy balance could be provided to help clarify the cost of operating the system. Drying the refuse is likely very expensive. (b)The paper indicates that conventional RDF systems have trouble processing rugs, mattresses, wire, plastic sheets, etc.; however, the UAH system would appear to have similar difficulties with these materials. (c) Have the melted plastic lumps been analyzed for con­ tamination and thus marketability? (d) One of the main advantages claimed for the process is the low plastics content, yet Fig. 2 shows 7.5% plastics in the minus 0.5-in. fraction. With 72% of all refuse as minus 0.5 in., the 7.5% amounts to 5.4% of the incoming refuse or 67% of all the plastic. (e) On p. 285, it is stated that "woody biomass is me­ chanically reduced to mulch," however, on p. 286, it states that some cardboard and paper was not reduced to below 0.5 in. How can wood or branches be reduced if not all paper is reduced? (f) When wet, dirt and other small objects have a tendency to stick to plastic, glass, metal, etc., how does this affect the quality of the recycled material? Would the 0.5-2-in. and the plus 2-in. material have to be dried just after the trommel in Fig. I (or all the material dried before the trommel)? (g) Odor and particulate controls would likely be needed on a commercial scale system for the processor and the dryer. Has this been addressed? (h) The percentages on p. 287 appear vastly different to those in Fig. 2 (and using the 5.7, 22.3, and 72% splits for the three components). The following table shows those dif­ ferences: