Project Description:
Water scarcity is a growing global concern, driven in part by the inefficient treatment of greywater—lightly contaminated wastewater from domestic sources such as laundry machines and dishwashers. Greywater, which does not require potable-level treatment, can be effectively reused in applications like irrigation following purification with decentralized treatment. This project focused on designing a sustainable manufacturing process for a nanofiltration membrane composed of cellulose triacetate (CTA) and chitosan for greywater reuse.
The process was modeled in Aspen Plus and divided into two main stages: (1) Polymer Composite Fabrication, where cellulose was acetylated with excess acetic anhydride to form CTA, which was then dissolved into a chitosan-NMMO solution to form an 8 wt% CTA-chitosan polymer solution; and (2) Phase Inversion, where the polymer solution was cast into membranes via immersion precipitation.
Based on this process, the system was designed to support an annual production target of 400,000 membrane packs. Although the design met production and performance goals, it presented significant safety risks at scale due to the flammability of reagents and the thermal sensitivity of NMMO. These factors make full-scale implementation hazardous without tight controls. A pilot-scale operation is recommended to validate process safety, optimize reactor conditions, and evaluate market readiness.
