Polymer flocculants are used to promote solid–liquid separation processes in wastewater treatment technologies, and bio-based flocculants possess many advantages over conventional synthetic polymers. Potato starch microgranules were chemically modified and mechanically sheared to produce modified starch flocculants. The effectiveness of produced cationic starch (CS) and cross-linked cationic starch (CCS) flocculants in the thickening and dewatering of surplus activated sewage sludge was evaluated and compared with that of synthetic cationic flocculants (SCFs) The flocculation efficiency of SCF, CS, and CCS in sludge thickening was determined by measuring the filtration rate of treated surplus activated sludge. Comparing the optimal dose of SCFs and CCS flocculants needed for thickening, the CCS dose was more than 10 times higher, but a wide flocculation window was determined. The impact of used flocculants on the dewatering performance of surplus activated sludge at optimal dose conditions was investigated by measuring capillary suction time. The filtration efficiencies (dewaterability) of surplus activated sludge using SCF, CS, and CCS were 69, 67, and 72%, respectively. The study results imply that mechanically processed cross-linked cationic starch has a great potential to be used as an alternative green flocculant in surplus activated sludge thickening and dewatering operations in municipal sewage sludge treatment processes.

The study explores the potential of thermoplastic biocomposites made from cellulose acetate, modified hemp seed hull particulate fillers and environmentally friendly plasticizer triacetin. Emphasizing the environmental advantages of utilizing natural materials, the research demonstrates the impact of different hemp hull chemical modification, such as alkali treatment or acetylation, on the mechanical properties of the resultant composites. Hemp seed hulls treated with 4–16% NaOH solution were studied using SEM imaging, FT-IR, XRD and chemical composition analyses. The study showed that alkaline treatment of hemp seed hull particles improved the mechanical properties of biocomposites, and the optimum concentration of NaOH solution ranged from 8 to 12%. The tensile modulus increased by 17–24%, and the tensile strength improved by 21–23% in biocomposites containing HH8 and HH12 fillers, while hardness increased by approximately 11–13%. It was also demonstrated that alkaline treatment of hemp seed hull fillers accelerated the biodegradation of biocomposite extrudates under aerobic conditions in a standard aqueous medium. Overall, the results demonstrated the potential of alkaline-treated hemp seed hulls as fillers in composite bioplastics.

This study investigates multiple extrusion regimens with twin screw extruder for valorising soy press cakes (by-products of soy drink & tofu manufacturing process) by varying physical conditions of extrusion (temperature and moisture content) for improving their morphological, physico-chemical, technological, and sensory parameters. Valorised soy press cakes were compared before and after extrusion. Four extrusion regimens (moisture content 30%-60% and temperature 110°C -120°C) were designed for producing different extruded samples. Small amounts (3%-6%) of untreated and extruded press cakes were utilised in the development of meat analogues. All samples showed comparable nutritional and trypsin inhibition activity with almost all samples possessing most essential amino acids above significant amounts. Press cakes with higher moisture indicated improved bulk density, water holding and oil holding capacity. Interestingly, the same samples also reportedly had texture more closely resembling native meat texture and scored the highest in overall sensory acceptance. Our results thus indicate that soy press cake samples from drink manufacturing process, when extruded with the regimen with 60% moisture and temperature of 120°C show the greatest potential in developing meat analogues.