Solar‐Powered Liquid Waste Reduction Using a Rotating Drum

ABSTRACT Solar energy utilization is a cost‐effective solution to reduce the volume of industrial wastewater. A rotating drum solar unit enhanced by forced air convection was designed, built, and tested. The unit may be operated under batch, semicontinuous, and continuous modes of operation. The effect of various operating parameters was investigated. The results showed that increasing the air flow rate resulted in a 62% increase in the evaporation rate, respectively. Increasing the drum rotation from 0 to 0.75 rpm increased the evaporation rate by seven‐folds. Higher rotational speeds reduced the evaporation rate. The evaporation increases by 1.5% upon reducing the mass in the basin by 1 kg. The evaporation rate ranges between 1.06 and 2.12 kg m −2 h during the cold and hot seasons, respectively. Comparing the experimental results with those theoretical ones calculated from models derived shows an excellent agreement. Economic analysis of the unit showed that it is feasible.