Waste to value: what are the opportunities for resource recovery in water?

According to SEMI estimates, approximately 500 process chemicals are used during the fabrication of semiconductor wafers. The situation is similar for other high-tech industries as well. However, only a relatively small amount of these materials is present in the final products with the rest of ending up in the exhaust air, water, or sludge.



This creates a lot of opportunities to reclaim valuable materials from waste streams – especially water – and turn waste to value.

Environmentally sustainable development is one of the most important drivers for the direction of resource recovery. However, it is not the only one. The natural availability of certain materials used in the high-tech industry may cause supply risks in the near future (see reference). Apart from the environmental perspective, the recovery of several materials can also translate to cost saving benefits.

There are different criteria and parameters that can be analyzed when considering the best path for resource recovery in water. The most important are the following:

o Stream segregation: effective stream segregation has become a key for both water recycling and resource recovery. An effective stream segregation is based on separating varying concentrations and types of contaminants. Very complex water mixtures increases the complexity of the recycling process and also increases the separation and resource recovery costs. o Materials quantity and price: when evaluating recovery opportunities, it is important to have in mind that recovery is economically feasible both in the case of low quantity but high value/price materials (e.g., germanium) as well as in low value but high quantity materials (e.g., copper). o Material form and recovery method: depending on the exact form of the material to be recovered in water, the right recovery technology needs to be chosen. The recovery process will be different for dissolved materials and for materials that are present in particulate form in water. o On-site vs off-site recovery: depending on the exact goal and facility infrastructure, retrofit solutions can be implemented on-site. Additionally, part of the recovery or purification process can even happen off-site in collaboration with material recycling companies or raw material suppliers. So far, there are different examples of successful material recovery across the sector. Copper and cobalt are two typical metals being recycled from water streams by the semiconductor industry. However, the full potential of material recovery opportunities in water is not yet known and still needs to be explored further. Recovery of waste sulfuric acid, calcium fluoride sludge, metals like germanium, gallium, and tungsten are definitely examples of materials worth considering. Now more than ever, we need to ensure a smaller environmental footprint across all high-tech industries and the key to that is to work together towards the further development of circular economy solutions. 

Reference:

Critical Raw Materials for Strategic Technologies and Sectors in the EU: https://rmis.jrc.ec.europa.eu/uploads/CRMs_for_Strategic_Technologies_and_Sectors_in_the_EU_2020.pdf