How to design a water balance for a processing plant operating in a water-scarce environment?
The concept of water balance for a processing plant is an accounting system that describes the movement of water into, around, and out of the industrial facility. It entails the calculation of all the inflow, usage, losses, and outflow of water in the facility. Operating under water scarcity conditions means that the facility operates in areas where there is more demand for water than there is availability, making sustainability imperative for survival.
For facilities operating in regions facing problems of climate variability and population growth, there is significant strain on watersheds in the region due to industrial demands for water (Dias et al., 2023). In such arid regions where processing plants operate, getting a stable source of water is one of the biggest difficulties. This is why adopting a mass-balance system is key to ensuring continued operations.
In the first step of developing an efficient water balance, a clear delineation of system boundaries is carried out. This is done by listing the sources of all external water, which includes such sources as municipal water supplies, groundwater, and surface water, along with all outputs, which include effluent water, runoff, and chemical or physical incorporation into the end product. Delineation of the boundaries reduces double counting of water flow and gives a good estimate of the amount of water needed by the plant.
After delineating the boundaries, accurate measurement of internal water conversions and losses needs to be carried out. In larger processing plants, there are losses in water due to evaporation during cooling processes, in solid waste, or unnoticed leaks from the infrastructure. Flow meters and computerized water management systems need to be used to accurately measure the water flows.
After collecting flow data and putting them into numbers, the plant will be able to balance water by focusing on the recirculation of water internally. In areas where water is scarce, maximum recycling of water from process streams or tailings will greatly help reduce the plant’s dependence on water supply from distant and possibly strained sources (Ihle & Kracht, 2018). Furthermore, adopting the ZLD technologies will help to drastically reduce liquid wastes that can be treated and reused again in the facility’s processes (Liang et al., 2021).
To conclude, the development of an efficient water balance will allow a processing plant to switch from a linear use of water to a more circular system of using water. Through accurate flow tracking and minimizing of water losses, industrial plants can become much more sustainable and environmentally friendly.
References
Dias, I. Y. P., Lazaro, L. L. B., & Barros, V. G. (2023). Water–Energy–Food Security Nexus—Estimating Future Water Demand Scenarios Based on Nexus Thinking: The Watershed as a Territory. Sustainability, 15(9), 7050. https://doi.org/10.3390/su15097050
Ihle, C. F., & Kracht, W. (2018). The relevance of water recirculation in large scale mineral processing plants with a remote water supply. Journal of Cleaner Production, 177, 34–51. https://doi.org/10.1016/j.jclepro.2017.12.219
Liang, Y., Lin, X., Kong, X., Duan, Q., Wang, P., Mei, X., & Ma, J. (2021). Making Waves: Zero Liquid Discharge for Sustainable Industrial Effluent Management. Water, 13(20), 2852. https://doi.org/10.3390/w13202852
