Inline UV-Vis spectroscopy to monitor and optimize cleaning-in-place (CIP) of whey filtration plants

Cleaning in place (CIP) is a necessary, complex and costly process employed all throughout the food industry. CIP of membrane filtration plants is especially delicate as membranes have limited stability towards temperature and can be permanently damaged or gradually changed by cleaning chemicals used for every day. We investigated the capability of inline UV-Vis spectroscopy to elucidate the dynamics of CIP of membrane filtration plants as a gateway to control and optimize the process. For this investigation aged membranes that had been used for industrial ultrafiltration of whey were transferred to a pilot plant equipped with inline UV-Vis spectroscopy on both the retentate and permeate side. Then the dynamics of multiple fouling and cleaning of these membranes were investigated. The results indicate that the first CIP step, caustic cleaning could be shortened and possibly reduced in concentration. The second step of CIP, enzymatic cleaning, seems to be active even longer than the anticipated time. Challenges, first findings and future steps of full scale inline UV-Vis spectroscopy are discussed. We conclude that inline UV-Vis spectroscopy can be used to optimize the processing time, energy and chemicals needed for cleaning in place of membrane filtration plants.