How will we produce copper in 2030 when there will no longer be enough of it in the mines? How can we utilise the energy contained in water? What about contaminants?
All eyes turn to wastewaters, which contain many unused business opportunities.
– Despite Finland’s abundant water resources, we should also pay attention to water. Energy production, for example, uses a lot of water for cooling purposes, says Mona Arnold, Principal Scientist at VTT.
For VTT researchers, wastewater is one possible source of minerals.
– We are developing methods for the efficient and profitable recovery of minerals, Arnold continues.
According to Arnold, we should change our way of thinking and start seeing landfills and water treatment plants as potential sources of raw materials and energy.
– Technology will be advanced enough in the near future to enable this kind of ’waste factory’ to run on its own.
New business from wastewater
Wastewater is a potential source of biogas, metals, fertilisers and biomaterials. The challenge with wastewater lies in its large quantities and weak solutions. Cleaning of wastewater is difficult and expensive, especially if taking place only when the water is discharged through a pipe to the waterways.
– Industrial wastewater must be treated cost-efficiently at the various stages of the process. At its best, treated wastewater can be recycled into the industrial process, explains Director Kaj Jansson from Outotec. Outotec is a Finnish company specialising in developing water- and energy-efficient refineries on a global basis.
Jansson mentions Singapore as a good example of a country that has solved several problems through wastewater treatment. When Singapore started to turn municipal wastewater into drinking water, it also managed to reduce environmental problems in the area. The simultaneous recovery of energy from wastewater reduces the energy demand of water treatment plants.
– Finland has excellent opportunities to succeed in the water business. We have know-how in improving both energy and recycling efficiency, as well as in developing intelligent operating systems. Along with the development of control and sensor systems, we will be able to effect a substantial increase in the efficiency of materials use in industrial processes, says Jansson.
Towards environmental efficiency indicators?
Jansson hopes a shared set of indicators will be introduced to measure the environmental friendliness of business enterprises – similar to the one already used for household appliances.
He suggests evaluation of enterprises on the basis of their waste utilisation rate: one point for recycling, more points for the extraction of main components and manufacture of by-products, full points for companies whose processes generate no solid waste or wastewater.
– This kind of indicator would help stakeholders to evaluate the present state of enterprises, as well as accelerate the implementation of new technologies, says Jansson.
Wastewater trends around the world
Turning municipal wastewater into drinking water is increasing because of the prohibitive cost of purifying salt water. The trend is towards energy-positive treatment plants, recycling of phosphorous, direct combustion of waste sludge and treatment plants deploying intelligent operating systems.
In forestry industry the transfer to closed process cycles has long been the trend – especially in Finland. At present, the R&D focus is on bioenergy production, recycling of phosphorous and trace elements, utilisation of lignin, lignan, extractives and hemicellulose, as well as the manufacture of new products – for example, nanocellulose – and intelligent operating systems.
In mining industry the trend is towards the recovery of valuable materials and contaminants, concentration plants with low water consumption, management of the present water-containing tailings ponds, and intelligent process control systems. The industry is also seeking more sustainable solutions through closing their internal water cycles.
Source: Kaj Jansson, Outotec
New methods from VTT
In its spearhead programme Green Solutions for Water and Waste (GWW), VTT has developed energy-saving methods for reuse of water in industrial processes, means for recovering minerals and materials from waste for recycling, and sensor technology for easy and rapid detection of pollutants.
Mycelium mats enable the recovery of metals: VTT has developed a filter made of fungi mycelium enabling efficient recovery of gold or hazardous arsenic without adding extra chemicals to the process. A fungi mat binds metals more effectively than activated carbon. The method, which is now at the laboratory stage, is likely to enter production phase in 3–5 years.
Algae put to work: Nutrients from sewage plants can be used to grow algae that produces bioenergy and biochemicals. VTT has developed methods that enable the cultivation of algae in Finland’s cool climate, where there is little daylight in winter.
Foam dewaters sludge: Sludge treatment is expensive and high in energy consumption. VTT has developed a method where foam that is spread over the sludge to extract more wastewater for reuse.
Pressure-free filtration: In industry, wastewater is normally recycled using pressure through a membrane. VTT has developed a forward osmosis method enabling filtering without energy-consuming pressurised filtering. This saves energy and costs, and releases more water for the process cycle.
Irrigation water from air: Water vapour contained in air can be condensed and recovered for use as irrigation water. This method is particularly suited for developing countries. A coating technology developed by VTT saves water collection costs.
Recovery of phosphorous: More phosphorous will be needed in the future for food and biofuel production. Phosphorous is produced in only a few countries at present. VTT has developed an extraction method for separating phosphorous from waste or low grade material into a liquid.
Sensitive sensors: VTT indicators facilitate rapid identification of low but hazardous cyanobacterial toxin levels and phenolic, hormone-like compounds, among others. The technology will be ready for the markets within the next few years.