MBRs Are More Cost-effective Than Ever Before

A cost model was developed to compare the capital and 20-year lifecycle cost of MBR vs. CAS treatment technology for a greenfield WRRF. Concept designs and cost estimates were developed for six treatment performance scenarios at two design flow capacities: 20 ML/d and 200 ML/d. Compared with a prior version of this model developed in 2012, MBR has become more cost effective compared to CAS in general, most notably for less stringent treatment requirements, while the cost savings of MBR for more stringent treatment requirements has improved, but more modestly. A primary driver of this is the advancements in membrane design, primarily the reduction in air scour energy for membrane cleaning due to new diffuser technology, greater membrane packing density reducing membrane equipment costs and further reducing air scour requirements, decreased membrane cleaning requirements and longer membrane life, and increased use of gravity permeation from membranes under average day operation.