Markus Engelhart

Protein separation from alkaline process water of shrimp waste processing industry using membrane filtration

The recovery of protein and caustic soda solution from shrimp waste alkaline process water was experimentally investigated by a two-step filtration process with polymer membranes of different molecular weight cut-offs. Experiments for nine combinations of microfiltration/ultrafiltration and nanofiltration membranes were conducted in batch-mode using a stainless steel stirred cell with a membrane area of 38.5 cm². It could be shown that this process concept is capable of separating protein and dissolved organic carbon from the alkaline hydrolysis of shrimp waste. Totally, more than 30 % of protein was fractionated by the first step filtration while the second step reached a higher protein rejection of more than 88 %. The protein concentrate could be reused as animal feeding and the recovered sodium hydroxide solution couldbe recycled to the production process.

Fouling mitigation in anaerobic membrane bioreactors using fluidized resin beads

This study focuses on the use of fluidized resin beads to mitigate fouling during ultrafiltration (UF) of the effluent of an anaerobic bioreactor. Two different module configurations were tested: A fluidized bed of resin beads was generated in a tubular UF membrane, and a hollow fiber (HF) UF membrane was submerged into a fluidized bed, respectively. During filtration of anaerobically treated synthetic wastewater using the tubular module, fluidized resin beads with a diameter of 0.5-0.71 mm did not show any beneficial effect. In contrast, the presence of fluidized resin beads (diameter of 0.5-0.71 and 1.00-1.25 mm) in the HF module reduced the fouling rate significantly. Furthermore, particle diameter and the bed voidage affected the cleaning efficiency of a pre-fouled membrane in the HF module. Interestingly, short-term filtration tests (<2 h) of a dextran solution showed that fluidized resin beads are able to minimize concentration polarization of a macromolecule, even in the tubular module. Therefore, it is supposed that fouling of the anaerobically treated synthetic wastewater was mainly attributed to the deposition of colloidal and particulate matter.