The benefits of recycling industrial wastewater can be immense; however there are many challenges that must be considered when establishing a wastewater treatment process.
The main challenge is in selecting the correct water treatment technology (or combination of technologies) for the wastewater. This is often a complex decision because there are many water technologies available; and multiple factors to take into account.
Common factors impacting water treatment technology selection are as follows:
Capital and operating costs
Maturity of technology
Existing on-site infrastructure (if any)
Existing resource supply chains (if any)
Treated water requirements
There are clear environmental benefits to recycling wastewater, but a well-designed treatment system should also be highly economical, minimising both initial investment costs and ongoing operational costs.
Technology maturity has ramifications for both investment and operating costs. Newer technologies often provide technical advantages (e.g. reduced consumption of resources, increased treated water recovery, improved equipment durability) which allow ongoing operating cost savings. However, the capital cost of new technologies can be expensive; and new technologies often have fewer operating references, which can be risky for early adopters.
A water treatment system’s consumption of resources should be minimised where possible, with power and chemical reagents reduced or recycled. Technology selection is often influenced by the type of resources readily available. Establishing new supply logistics is difficult and costly, and thus utilisation of existing resource supply chains or on-site reagent production facilities is always beneficial.
Another challenge is the management of contaminants once they have been removed from the wastewater – and technology selection has a major impact on this. Removed contaminants can be in a solid (precipitation) or liquid (concentrated brine) phase, and usually require further treatment or disposal. Highly optimised water treatment systems both remove contaminants and convert them into reusable by-products (e.g. salt, fertilizer, chemicals).
The contaminated nature of industrial wastewater can cause poorly designed equipment to fail, often due to accumulation of foulants or chemical corrosion. This can be particularly problematic if the plant is located in a rural area with limited access. It is crucial that the selected water treatment technology is robust and supplied with sufficient spare parts; and that maintenance requirements are minimised.
There are many challenges in industrial wastewater treatment; and selecting the correct treatment technology is crucial in providing the best possible chance of success. Conversely, selecting the wrong technology often magnifies the challenges, causing continuous issues and inefficiencies.