Treatment of metalworking fluids using a submerged anaerobic membrane bioreactor (<scp>SAMBR</scp>)

Abstract

Abstract BACKGROUND The role of biodegradation and physical–chemical mechanisms involved in the treatment of metal working fluids ( MWFs ) using a submerged anaerobic membrane bioreactor ( SAMBR ) was assessed in this research. Two SAMBRs were employed in series, with the second SAMBR being fed the permeate from the first bioreactor. RESULTS Results showed a low biodegradability of the MWF both in batch tests (bioconversion efficiency ≤ 3%), and operating the bioreactors continuously (bioconversion efficiency ∼0%). Among the physical–chemical removal mechanisms identified, it was found that bio‐adhesion was the most important in MWF removal (removal rate of 96.0 ± 1.64%), whereas membrane rejection was not significant (removal rate of 0.2 ± 0.18%). However, it is expected that membrane separation will play an important role in removal after bio‐adhesion has been saturated. CONCLUSION The inhibition of the hydrolytic/heteroacetogenic biomass was the most problematic aspect in anaerobic digestion, resulting in the need for bioaugmentation of specific microorganisms to degrade MWFs . In the case of non‐adaptation during long‐term operation, the bio‐adhesive propensity of MWFs could be used as a potential method for removing spent MWFs from wastewater streams. © 2014 Society of Chemical Industry