The MBR Book: Principles and Applications of Membrane

of non-point source pollution control and estuary protection projects. It has provided
more than $4 billion annually in recent years to fund water quality protection projects
for wastewater treatment, non-point source pollution control, and watershed
and estuary management. In total, CWSRFs have funded over $52 billion, providing
over 16 700 low-interest loans to date (USEPA, 2006c). Other sources of funding for
US projects are Water Quality Co-operative Agreements and the Water Pollution
Control Program, amongst others. As with regulation on water use and discharge,
individual states may have their own funding arrangements (ADEQ, 2006; CEPA,
2006; GEFA, 2006).
Again, the above examples are only a snapshot of what is available globally, as a full
review is beyond the scope of this book. However, it is evident that governmental
organisations are now offering incentives for investment in innovative water technology
projects; as a result, MBR technology becomes more attractive in terms of affordability.
Having said this, the choice of technology is not normally stipulated by
legislators, regulators or incentive schemes but may be inferred by the performance or
quality standards set. The benefits of MBRs from the perspective of recycling is (a) their
ability to produce a reasonably consistent quality of delivered water independent of
variations in feedwater quality; (b) their relative reliability and (c) their small footprint.
1.4.3 Investment costs
Increasingly reliable and a greater choice of equipment, processes and expertise in
membrane technology are available commercially for a range of applications, reducing
unit costs by up to 30-fold since 1990 (DiGiano et al., 2004). Future cost reductions are
expected to arise from continued technical improvements and the economies of scale
derived from a growing demand for membrane production. Costs of both membranes
(Fig. 1.4) and processes (Fig. 1.5) appear to have decreased exponentially over the past
10–15 years, with whole life costs decreasing from $400/m 2 in 1992 to below $50/m 2
in 2005 (Kennedy and Churchouse, 2005). Such reductions have come about as a
result of improvements in process design, improved O&M schedules and greater membrane
life than that originally estimated (Section 5.2.1.1). Having said this, although
further cost reductions are expected in the future, there is some evidence that
membrane purchase costs specifically are unlikely to decrease significantly unless
standardisation takes place in the same way as for reverse osmosis (RO). For RO technology,
standardisation of element dimensions has reduced the price of the membrane
elements to below $30/m 2 for most products from bulk suppliers.
1.4.4 Water scarcity
Introduction 9
Even without legislation, local water resourcing problems can provide sufficient
motivation for recycling in their own right. Water scarcity can be assessed simply
through the ratio of total freshwater abstraction to total resources, and can be used
to indicate the availability of water and the pressure on water resources. Water
stress occurs when the demand for water exceeds the available amount during a
certain period or when poor quality restricts its use. Areas with low rainfall and high