Wastewater Treatment in the Paper Industry: Recovery of Energy and Service Water with Innovative Solutions
Fibers, water and energy are all needed in large quantities to produce cardboard, paper or pulp. To survive in tough international competition, companies in the paper and pulp industry have been working for years to reduce their costs. With the wastewater technology of the DAS Environmental Expert GmbH manufacturers in the paper industry can not only reduce their fresh water demand significantly, but also the required energy amount.
Recycling for Pulp and Paper Wastewater
A well-designed wastewater treatment is of great importance to companies producing pulp, cardboard or paper. Regardless of which products are produced and which processes the respective plant applies — water is one of the most important resources. Water is needed in large quantities to make paper pulp out of fibres such as cellulose, wood or recovered paper. If recovered paper is used, the print colours are often removed using a suitable de-inking process. The paper pulp is then treated with a range of additives such as fillers, colourants or auxiliary materials and finally processed into a paper web in the paper machine.
Most of the water is removed at this point using meshes and heated cylinders. DAS Environmental Expert therefore is dedicated to support you with smart concepts on how to smartly use the wastewater from that process. In general, there are different approaches possible. To save on costs, some plants already handle water in a closed loop. Because of the costly nature of water processing, paper manufacturers around the world have in recent years worked hard to reduce their water footprint.
Heat Recovery from Process Water in a Paper Factory
Today, the production of paper, cardboard and pulp in Germany still requires an average of almost eleven litres of water per kilogram of product, and some countries use even more. If the water is to be used again in the production, the purification must be carried out with high quality. Our experts use a variety of technologies to overcome challenges such as salinization, scale precipitation, foam and odor formation.
Wastewater from paper factories includes substances such as de-inking chemicals, bleach, process chemicals and additives, in addition to leftover fibres. It is characterised by a high chemical oxygen demand (COD) and is predominantly treated first mechanically, followed by full biological treatment in either a factory-operated or municipal wastewater treatment plant.
We are looking forward to advice you in the selection of suitable processes for a reliable and energy-saving wastewater treatment. We also offer a special heat exchanger to significantly improve the energy balance.
Heat Exchanger for Wastewater Treatment
Wastewater coming from the paper machine is relatively high which is a danger to the biological wastewater treatment to follow. Furthermore, to prevent damage to the river, an official upper temperature limit is also in place for discharging wastewater.
The environmental experts from DAS have come up with a clever technical solution for this problem: The innovative heat exchanger E‑Plate enables heat transfer from wastewater to process water. It is specially designed for wastewater contaminated with solids and requires little maintenance. For example, our heat exchanger is applied successfully at Schumacher Packaging GmbH in Schwarzenberg/Erzgebirge. Click here to find the proper case study.
Even in technologically advanced Europe, a factory still loses around 300 kilowatts of energy per ton, according to wastewater data from the Papiertechnische Stiftung (PTS) in Munich, Germany. The use of heat exchangers can significantly improve this energy balance. We are happy to calculate it together with you: the investment in a heat exchanger pays for itself in a very short time.