TECHNICAL CONSIDERATIONSMost industries use water as a process medium and/or as a heating and cooling medium. As a consequence, wastewater is produced as an undesirable by-product containing substances from the manufacturing processes. Industrial wastewater treatment is concerned with purifying the water stream to concentrate and remove harmful components before discharge to the municipal wastewater network or directly to a surface water in the environment. Increasingly, efforts are being made within industry to reduce wastage and recycle such water back into the manufacturing process in order to improve water efficiency and reduce harm to the environment.
The nature of impurities in wastewater varies widely depending on the industry. In New Zealand, industry is dominated by agriculture and food processing, which utilise large quantities of fresh water for washing, cleaning, material conveying, bottling and pasteurising, which in turn produces large quantities of wastewater. This wastewater can be generalised as non-toxic and biodegradable, however, it has high concentrations of BOD (biological oxygen demand) and suspended solids and can contain cleaning chemicals used in the production process.
An example is in the dairy industry, where large quantities of water (“cow water”) are removed from the milk during conversion to butter, cheese, whey and milk powder through membranes or evaporation processes. These high-quality water streams represent opportunities for re-use and recycling with the appropriate purification processes. Re-use in cooling tower makeup, cleaning in place or product reconstitution are possibilities. Visentia can work alongside your equipment supplier to ensure that recycled water is fit for use from a chemistry and biology perspective for the application it is intended.