Applications
Potential for implementation of GDM technology
GDM technology can be attractive for household and community drinking water treatment. GDM provides a physical barrier for particles, bacteria and viruses. It does not require any back-flushing, cross-flow, chemical cleaning or disinfection. The pressure of 40 mbar required for ultra-low pressure UF can easily be obtained by gravity in most situations. Thus the design of the GDM based systems for treatment of drinking water may be kept simple and no expensive pumps, control equipment or pressure-resistant housing is required.
The membrane service life expectancy is estimated to be approx. 7-8 years in large-scale applications. In GDM no chemical cleaning is used and even higher service life could be expected comparing to large scale applications. Thus, we expect that GDM systems could be operated for at least 8 years without considerable maintenance.This makes GDM attractive for stand-alone applications on decentralized scale, such as drinking water treatment systems for household and community use.
GDM-filter for household use
System costs
Besides the membrane module, a household system based on GDM requires two tanks for storage of raw and treated water. The costs of the tanks are expected to be relatively low, especially when produced locally, and thus the total costs of the system will be determined mainly by the costs of the membrane.
For household applications, only about 20-40 L/day of drinking and cooking water per family is needed. Assuming stable flux of 4-10 L.m-2h-1, the membrane area needed is less than 0.5 m2. At present, high quality membranes for a market price of < 40 US$/m2 are available and membrane costs are decreasing. Thus, the membrane costs are expected to be less than 20$ per household system. The housing is expected to add about 5-10$ to the system costs. Thus, the total costs of a household system are expected to be about 30 US$, or 3.75$ per household and year, assuming the service life of 8 years. These costs do not exceed the affordability limit of 10 $ per household and year, defined by the WHO for the poorest part of the world’s population.