When it comes to the paper you put in your printer, that you use to clean up spills, or that brings you the news (the old fashioned way), you probably don’t think too much about where it comes from – unless, of course, you happen to work in the paper, pulp, or recycling industries. What many people don’t realize is that making paper not only requires the use of trees, but also the use of water.
The water that is used in the process of manufacturing pulp, and later paper, is considered wastewater, just like much of the water used in various industrial concerns. This byproduct of the pulp and paper industries is therefore subject to wastewater treatment before it can be discharged.
Naturally, it is not performed in precisely the same way as, say, sewage water treatment, but before this water can be returned to nature or recycled for other purposes like irrigation, it must undergo treatment to ensure that it is safe and clean. The water treatment systems and processes not only differ from industry to industry, but also between pulp and paper production, which are separate.
Here is a brief overview of why wastewater produced in the pulp and paper industries must be treated and the processes used to treat these contaminated water sources.
In order to create the pulp used to make paper products, wood chips must be broken down and often bleached. Wood may be broken down by either alkaline (kraft) or acid-based processes, both of which produce wastewater. The former method may be more effective and efficient, but it also creates more chemical wastewater.
Next comes the bleaching process, which produces additional wastewater. The solution for treating this byproduct of pulp production is a water treatment system that allows pulp operations to recycle and reuse much of the water that might otherwise be wasted.
Paper production is a separate process from pulp production. Paper may be created from either wood pulp or the pulp created by breaking down recycled paper products. The quality of the pulp will determine which paper products it can be used for.
There are several different processes paper may undergo, with different products resulting. The use of both water and additional chemicals in the process of creating paper products generates additional wastewater, which must also be treated.
All in all, the paper and pulp industries require huge amounts of water for production processes, but much of this water can be recycled and reused immediately by the plants themselves, while some may be repurposed for other uses.