Process water is wastewater that is produced during a manufacturing or processing operation. The contamination of the process water depends on the industry. Depending on the substances that dissolve in the process water, different methods are used to purify it. Depending on the requirements of the industry or the company, the purification processes must be designed differently.
Process water is produced in various industries. These include the plastics recycling industry, the food and beverage industry and the textile industry. These sectors need a lot of water for the production or processing of their product. Washing plastics and food, using cooling water or ensuring hygiene in one’s own company are just a few examples.
The aim of treatment is to reuse the water in the washing process. Customers save on two fronts at once: Firstly, almost no fresh water needs to be added. Therefore, a maximum of five percent fresh water is required. Secondly, there is no need for discharge into a municipal sewage treatment plant. Since no or hardly any wastewater leaves the washing process, no costs are incurred here either.
The following components can mix into the process water: Fats and proteins due to organic contamination, plastic abrasion, salts, sugar, and other organic substances, printing inks, washing chemicals, cellulose fibres, and glue from labels. This has an impact on the sum parameters COD and BOD5. While the biological oxygen demand can be as high as 12,000 mg/l, the chemical oxygen demand usually increases to 20,000 mg/l. The pH value is similarly variable, usually between 6 and 14.
The treatment of process water is worthwhile if the operator can save water and thus costs or reduce expenses elsewhere.
