The MegaMagnum spiral reverse osmosis (RO) and nanofiltration (NF) element has an unprecedented capacity that comes from its 18-in. diameter and 61-in. length. MegaMagnum elements significantly reduce the installed cost of large and medium-scale RO systems designed for brackish water treatment or municipal water reuse, as well as for NF systems where softening or organics removal is a desirable treatment for drinking water supplies.