Environmental Engineering Reference
In-Depth Information
using this reclaimed water for agricultural and industrial applications. Furthermore, it
also has the support of most Americans. According to a recent GE report, which surveyed
3000 consumers in the United States, China, and Singapore, >80% support “toilet-to-turf”
uses—agricultural irrigation, landscaping, industrial processing and manufacturing, toi-
let lushing, and car washing. It is a signiicant inding, considering that 36 US states face
water shortages in the coming year and 5.3 billion people worldwide will be vulnerable to
water shortages in the next 10+ years.
The adoption of advanced technology, including nanotechnology—referencing the
increasingly small pore size of membranes or ilters for removal of contaminants—
combined with forward-thinking government policy and education will play a major role
in the evolution of water and wastewater treatment and reuse. This chapter discusses sev-
eral of these advanced membrane solutions, explores speciic GE innovations, and also
discusses how industry collaboration and policy can play a stronger role in making water
reuse a priority.
39.1 Nanofiltration
Nanoiltration (NF), the popularity of which has grown considerably during the last sev-
eral years, offers opportunities to develop next-generation water supply systems. The NF
membranes and their properties are quite diverse but can generally be described as hav-
ing rejection characteristics that range from “loose” reverse osmosis (RO) (hyperiltration)
to “tight” ultrailtration (UF). The uniqueness of these membranes is highlighted by their
ability to selectively reject different dissolved salts, and have high rejection of low molec-
ular weight dissolved components. NF membranes are mainly used to partially soften
potable water, allowing some minerals to pass into the product water and thus increase the
stability of the water and prevent it from being aggressive to distribution piping material.
Additionally, NF membranes are inding increasing use for purifying industrial efluents
and minimizing waste discharge (Figure 39.1).
FIGURE 39.1
GE's Nanoiltration Membranes' innovative spacer design and unique three-layer technology contribute to
lower fouling and optimal cleaning properties in tough-to-treat applications.
