How to improve water reuse in concrete batching plants

In recent years, much has been discussed about conscious consumption and water savings across many fields of activity. One of the most prominent examples is concrete pouring services, since the amount of this resource used in them is significant. That is exactly why more and more companies are looking for alternatives to optimize water consumption in a practical way, without affecting product quality or production efficiency.

One of the most viable options for this is to improve water reuse in concrete batching plants. In this article, we will discuss the importance of this action, how to carry it out effectively, and which technologies are available on the market to implement it.

The use of water in civil engineering

Water is an essential element in concrete production, used as an input since it hydrates the cement and enables the formation of the chemical bonds that give the material strength and durability.

The crux of the matter is precisely the amount of water added to the mix, since making a single trip with a fully loaded mixer truck requires more than a thousand liters of water.

It is also worth remembering that water is not used only in concrete production. Mixer trucks must be washed, both inside the drum and outside, to prevent the buildup of splashes and to keep gravel residue from coming loose and reaching other vehicles on the streets. This process uses approximately 700 liters per trip, and this water should not be discarded without treatment, as it can contaminate the soil or aquatic organisms.

How to implement water reuse in concrete batching plants?

A good implementation requires a significant initial investment, but it can bring long-term benefits for the company and for the environment.

Most companies use what is known as a settling pit, a waste bay combined with a sedimentation system that aims to reuse the water from the internal washing of mixer trucks. The leftover solid material must be disposed of correctly.

Less often, companies opt for recycling equipment, which requires a larger investment. It separates the water from the other components: the water is pumped into reservoirs and reused in the process, while the solids generated can also be reused in certain types of concrete.

Before taking any initiative, it is important to carry out a technical and economic feasibility study to determine the best solution for your concrete batching plant.

Can reused water be used in concrete production?

There was a time when only potable water could be used for concrete production. However, in more recent years there have been some changes to this rule, driven by the need to save and reuse the water used in the process. Thus, other types of water can be used, as long as they meet the minimum requirements established by the ABNT NBR 15900-1:2009 standard:

• The additional mass of solid material in concrete resulting from the use of water recovered from processes in concrete preparation must be less than 1% (mass/mass) of the total mass of aggregates present in the concrete.
• The possible influence of using this water must be taken into account if there is any special requirement for a particular type of concrete to be prepared.
• The amount of recovered water must be distributed as uniformly as possible in the preparation of the concrete.

Benefits of water reuse in concrete batching plants

Water reuse in concrete batching plants offers countless benefits, both for companies and for the environment, with cost reduction being one of the most significant. When this resource is reused, the consumption of potable water decreases, which also lowers the water bill.

In addition, efficient water use contributes to the preservation of water resources, resulting in a lower environmental impact.

There are other technology options on the market to implement this practice. Automated dosing systems, such as Kartrak, for example, reduce losses caused by human error in dosing processes, avoiding waste. Another good initiative is to have maintenance management systems that help properly monitor the operation of the plant's equipment. By doing so, it is possible to produce high-quality concrete in a more sustainable and efficient way.