How to ensure success in mining water treatment operations
Mining & Metals’ transition from compelled water treatment towards advanced operations
How should resources like water be used in an industry which has to be transformed to reduce its environmental impact? Questions regarding the environment, and water, in particular, have become more urgent as access to clean water has been identified by the UN as one of the sustainable development goals.
Written by Linus Lejon Isaksson with co-editors Janne Tikka, Jyrki Noponen and Kirsi-Marja Haanpää
The standard goal for process industry water management is to reduce, reuse and recycle the industrial water. However, it is important to understand that in these R-processes, the quality of water will start to deteriorate. Reused or recycled water can contain more dissolved elements, have higher pH or contain other contaminants that can impact the final product or damage production equipment.
Within the mining and metals industry, it is mainly the suspended solids and dissolved elements that are the primary sources of contaminants in recycled process water. However, biological components have more recently been increasing as decomposition of nitrogen compounds utilizing bacteria is done more in production.
What is clean water?
The definition of clean water varies among respondents. This seemingly simple question has multiple perspectives depending on who answers it. From the process industry point of view, clean water fulfills the environmental permits and directives that need to be considered. This is society's definition and perspective of what clean water is.
Dodging pitfalls while moving towards more efficient water treatment
In order to enable obligatory water recycling and reuse in the production processes, mining and metals operators need to pay more attention to existing water treatment processes and plants. An overall holistic view of plant and operations is required to ensure that one solution is not causing harm to another.
One of the typical pitfalls in water treatment is unit process sub-optimization, which is when whole the production plant and all parameters are not considered one entity. This is where good intentions often go wrong, but this can be avoided:
When developing a new production process or expanding an existing one, information from all parts of the operations needs to be gathered in order to find all relevant parameters. These agreed parameters need to be revisited throughout the entire lifecycle of the treatment process to allow any reactions and changes. It is not uncommon that certain demands are uncovered once development, discussions and preparations for the future are started. Well-considered and prepared parameters enable the optimal treatment solution to be found as well as lead to operational changes that eliminate contaminants in production processes and decrease OPEX in the long term.
Misconceptions may lead to inefficiency
The general opinion has been that any water treatment solution is a necessary evil and not something that adds value and benefits plant production. We at AFRY claim that a water treatment unit should get the same dedication and access to resources as any other part of the plant. A water treatment process and plant are often one of the most delicate parts of the entire production flow sheet. Although the plant and processes can be complex, a water treatment plant is still fairly easy to manage during normal operations. Most of the water treatment processes can be monitored and managed by using pH-probes, flow meters and automatic samplers - instruments which most industries have experience using. Despite being highly automated, a water treatment plant does require staff. If not the operators or technicians, who will drive the operations and develop the plant to achieve even higher performance over time?
Monitor, analyse and improve on a constant basis by taking a holistic view
After implementing an operating water treatment plant, you need to follow and track the performance the same way as any other production line or unit. This is how operators and technicians are able to improve plants and make them even more cost-effective over time.