Biodegradability and adaptability studies of geothermal wastewater in a biological treatment plant

The purpose of this study was to identify the optimal conditions for the operation of biological treatment
plant by carrying out biodegradability tests for geothermal wastewaters with high salt content. The
biodegradation tests for geothermal wastewaters were carried out in a discontinuous flow bioreactor. The
phases of the biodegradation process were: adaptation of the biological sludge, control of the biological
treatment process, experiments in the laboratory bioreactors (BATCH). The results of the biodegradability
tests revealed that geothermal waters with high salt content influence the treatment process. The dilution
of these waters with domestic water up to chlorine concentrations below 800 mg L-1, makes the purification
process to have a good biodegradation yields for CCO-Cr (about 75%) and CBO-5 (about 72%). If these
geothermal wastewaters are not diluted to concentrations lower than 800 mg L-1, the biological sludge after
6 days is mineralized, which makes the use of biological treatment plant to be impossible.