THE INFLUENCE OF THE ADDITION OF PRE-OZONATED WATER PRODUCTION IN THE PERFORMANCE OF AN ANAEROBIC REACTOR

Abstract

Water production is an undesirable by-product presented in oil extraction. This residue is distinguished by the generated volume, toxicity and high salinity. These characteristics make it difficult to biological treatment, necessitating pre-treatment and / or dilution with other residue in order to increase their biodegradability. Thus, this research studies an alternative treatment for oil water production in biological reactor on anaerobic condition preceded by pre-treatment by ozonation on a laboratory scale. The pre-ozonated water production (POWP) was mixed with a synthetic substrate simulating sewage (SS) in increasing proportions in five operational phases. The results showed an average of 75% removal of organic matter in terms of COD, for phase 1 (without addition of POWP). In subsequent phases, it was found that efficiency decreases with the increase of the percentage of POWP, with values of 73%, 64%, 47% and 23% for phases containing 2%, 5%, 8% and 10% POWP, respectively. The study of the temporal profile of organic matter showed that the batch reaction time could be reduced from 22 to 8 hours. These results showed that 5% is the largest POWP dilution percentage at SS for the system to operate with stability and COD removal efficiency over 60%. The inhibition of anaerobic process may be attributed to osmotic stress caused by high salinity, which in phases 4 and 5 were, respectively, 7.9 gCl-.L-1 and 11.7 gCl-.L-1.

Key-words: Anaerobic treatment, biodegradability, water production and pre-ozonation.