Paper industry has always been a considered large consumer of natural resources; especially water, as it’s a fundamental element in different stages of the production process.
In recent years, numerous companies in the industry have worked to reduce water consumption and have invested in systems that allow for the reuse of water inside their factories. However, the quantity of water continually consumed in the industry remains of importance.
Another aspect to consider, contrary to what occurs in other industries, is the dependence on good quality water for production of paste and paper in order to achieve a good product. In certain cases, depending on where the factory is located, the need can arise to consume available water from the network of local water supplies.
To overcome this problem, the main challenge of the paper industry has been aimed at reusing water within their factories.
Since the production of paste and paper requires water in numerous stages of the production process, incorporating wastewater treatment technologies in the production chain makes it possible to reuse a single water current in the same stage of the process, or it can be sent and reused in another stage.
Thus, water whose quality has been weakened (primarily due to higher concentration of organic matter and suspended solids) can be treated by filtration technologies, coagulation-flocculation, membranes, or evaporation while remaining part of the production process without continuously resorting to external resources.
Choosing the best technology to obtain quality water will depend on the composition of the feed water to be transformed, since at times, biological treatment can prove sufficient while on other occasions, more extensive treatment is required.
The same is true when we talk about reuse, since the composition of the effluent will determine the most appropriate system for recycling it so it can be utilized in the same process or sent to a different one.
In the last decade, we have seen great progress in the use of water coming from urban wastewater treatment plants (WWTP). Water is subjected to treatment to enhance its quality in order to be incorporated into the production process. In this way, the consumption of drinking water destined for the population is avoided.