Using Ceramic Nanofilters to Turn Wastewater into Reusable Components
Figure 1. A new concept for using ceramic nanofiltration membranes to treat municipal wastewater into quality water,
energy and fertiliser.
Objectives
The aim of the research is to treat wastewater into reusable components such as water, fertiliser nutrients and energy. From laboratory and pilot scale, the research will be scaled up to a demonstration plant supplying quality water to regional industries, with potential for deployment in other regions. The ultimate goal is to apply the research to large cities and rapidly urbanising areas, creating sustainable, low-cost decentralised systems for treating and reusing municipal wastewater.
Content
As people live and work, the wastewater they generate must be cleaned before discharge into the environment. Moreover, the amount of clean and safe water is decreasing worldwide, and current sources of fertiliser nutrients are being depleted (e.g. phosphate mines). This research changes the outlook on wastewater by developing the concept that energy, fertiliser nutrients and high-quality water can be extracted directly from municipal wastewater. In this concept, municipal wastewater is regarded as a valuable resource rather than waste (a valuable resource that has not been properly used).
The wastewater-as-resource concept is especially important for megacities and rapidly urbanising areas around the world, where municipal wastewater is not only rich in nutrients and stable in quality, quantity and temperature but also inexhaustible. The concept is applied in decentralised treatment, reducing the large investment costs of wastewater infrastructure.
The research uses fine screens to remove large particles, followed by newly developed ceramic nanofiltration membranes, which are suitable for this application thanks to their high mechanical and chemical strength. The wastewater is concentrated so that more than 80% is recovered as water. This water is then purified by reverse osmosis for industrial use, while the concentrate from the ceramic membranes and screenings are sent for digestion to produce biogas, and the nutrients from this stream are processed into fertiliser. Figure 1 illustrates the ceramic nanofiltration membrane concept.
In conventional wastewater treatment plants, large amounts of energy are consumed for aeration and mineralisation of the sludge, whereas in this project the organic matter serves as a renewable energy source. In addition, water from conventional wastewater treatment, which is usually discharged, is now reused directly.
Figure 2. Ceramic filters (Illustrative images – source: Internet)
