Abstract
The residual frying oil (RFO) is part of one of the residues generated daily in homes, industries and public offices. Uncontrolled disposal of waste frying oils, in sinks or thrown directly into the water, entails a series of environmental damages, such as clogging of pipes in sewage systems and increases the costs of treatment processes, in addition to pollution. The collection and reuse of these waste oils prevents their improper disposal and brings benefits to the environment. The percent recovery of residual oil from fried food depends largely on the washing operations. These operations are also responsible for the effective separation of the organic and aqueous emulsified waste phases, so that they have the lowest oil content, while the oil can be further used for the production of soaps and detergents. In this work, operating conditions to improve the chemical wash process of the RFO by industries were improved to generate a suitable effluent to subsequent physicochemical treatment by Dissolved Air Flotation (DAF). After packaged in capped collectors, the RFO was washed by the addition of chemical reagents (HCLO3, NaOH and NaCl). The material was then treated via DAF, with a biosurfactant acting as a biodegradable collector in a laboratory scale prototype operating in a continuous modus. The experiments were carried out according to a Central Composite Rotational Design (CCRD) in the form of 22. The factors were the ratio of the flow of the effluent to be treated and the flow of biosurfactant and the ratio between the flow of air and the effluent recirculated for producing microbubbles. As a result, it was recovered the aqueous phase with aid of flotation efficiency of 95.5 %, giving a statistical model prediction for the optimum condition of a recovery process of water that can be reused in the actual industrial process.
