A water balance can be described as the measurement and determination of flow in and out of a system, which is considered the main building block in developing a salt balance (estimation of salt concentrations within the reticulating system). As mining and industrial operations are critically dependent on water resources, a water and salt balance serves as the ultimate tool to assess the current status, in addition to identifying discrepancies, shortages and leakages within the distribution network. When water is continuously re-circulated in the interest of water conservation, salt concentrations gradually increase, posing complications to the system which include:

• Corrosion of metal components;
• Brine accumulation categorising as hazardous material; and
• Increased operational treatment and replacement costs. 

Development and implementation of related balances provides for a pro-active approach to converse and optimise management strategies for a sustainable water use principle. An eight (8) step approach is employed for development of the balance which is extensively described by the DWAF Best Practice Guideline-G2: Water and Salt Balances as published in August 2006. The main rule associated with a balance is set at: inflow is equal to outflow taking into account change in storage during a time period. For ease of reference a step-breakdown is illustrated within the flow diagram below:

In summary, the reticulation system and associated data (volumes and concentrations) is utilised to conceptualise the flow distribution and water/salt volumes mathematically incorporated to determine the overall water and salt balances. A central database is compiled during a phased approached comprising of the following aspects:

• Collation of the available water volume and quality data (inclusive of rainfall, evaporation, groundwater inflow and seepage);
• Boundary identification;
• Itemisation of process units (e.g. surface plants, water facilities etc.); and
• Conceptualisation of the water reticulating system and interconnection of the process units.

For cost effective water and salt balance design, conceptualisation and execution, please do not hesitate to contact our highly qualified and experienced consultants at ENVASS.