Treating process wastewater employing vacuum distillation using mechanicalvapor recompression

Process wastewater has been successfully treated using an enhanced variable vacuum distillation system (VVDS). the removal of contaminants is achieved initially by degassing the liquid under an intense vacuum which removes th e volatile organic compounds. The resulting liquid is then distilled under a vacuum using mechanical vapor recompression. The system was invented by D erald McCabe. This innovative treatment system removes virtually all of the contaminants, such as TSS, TDS, BOD5, COD, heavy metals and mineral compounds. The resul tant aqueous portion normally returns to a neutral pH. Due to the unique sy stem operation, scaling problems (often encountered in conventional distill ation) have not been detected in this system. The VVDS is extremely energy efficient because the heat for distillation is generated and recycled mechanically. Using electricity as the energy sourc e, the approximate operating cost, based on $0.05 KWH, may vary from $0.005 to $0.01 per gallon depending on the size and capacity of the equipment. Based on applications in waste streams performed to-date, the VVDS process has yielded a distilled water stream and the concentrated solids has been u sed as a byproduct or as a concentrated non-dischargeable waste for disposa l.