Membrane ultrafiltration of a nonionic surfactant and inorganic salts from complex aqueous suspensions: Design for water reuse

Complex aqueous suspensions containing a nonionic surfactant, phosphates, silicate, hypochlorite, oil, and kaolinite particulates are subjected to continuous flow membrane ultrafiltration with noncellulosic membranes. The ultrafiltrate water flux and the rejections by the Millipore PSAL membrane of total organic carbon, surfactant, and total phosphate are related by stepwise, multiple linear regression analysis (logarithmic model) to transmembrane pressure difference, thin channel velocity, membrane resistance, and feed solution concentration. The variables are adjusted to eliminate gel polarization and to minimize concentration polarization. The data are extended, by the development and use of a computer simulation scale‐up procedure, to a 1 000 cm³/s (23 000 gal/day) laundry waste treatment and water recovery unit. The procedure considers banks of modules in series, banks in parallel, and a parallel‐series‐tapered arrangement. Membrane area requirements per unit ultrafiltrate water flux and solute rejections are predicted for water recoveries up to 95% of the inlet flow rate.