Saving water

Nowadays many companies prioritise saving water for both environmental and economic reasons. Eco-Vision has plenty of experience in this field. We have an impressive list of references, having built various systems for the concrete, surface treatment, pharmaceutical and automotive industries.

Analysis of water management

You will only get to the root of a problem if you know it in all its aspects. That is why at Eco-Vision, each project starts with an in-depth analysis of the customer’s water resources. “We thoroughly investigate the origins of the wastewater and analyse opportunities to reduce water consumption within the manufacturing process. We painstakingly record any aspects that stand out. Once we have done our homework, we can determine the most appropriate solution for each individual customer, what techniques will yield the best results and the savings that will be available to the customer thanks to the use of these applications.”

Recycling in the concrete industry

Nowadays concrete companies are required to install a closed-loop water system. Consequently, many companies invest in systems to thoroughly purify wastewater generated through the washing of products such as pavers or tiles. The resulting integration of water treatment systems into the production process facilitates extensive recycling. Eco-Vision has already completed several such projects, combining flocculation with sedimentation, among other techniques. Selective sedimentation can help separate the fraction of fine particles from a suspension. This leads to the creation of small flocs, which only grow through gentle agitation. To promote this process, we add a flocculating agent. These high molecular weight substances (polymers) attract smaller flocs, resulting in larger flocs. In the next step of the process, the purified water is “softened” or demineralised, removing calcium and allowing the water to be reused for washing. The water and residue are thus contained in a closed-loop water system. The recovered sludge has a consistent structure. As it is easily mixed into the sand and cement, it can be reused in the production of new concrete. The company is left with nothing to discharge.”

Closed demin-installations

In many cases, wash water plays a crucial role in the process. Stringent requirements apply to wash water’s purity and conductivity (20 to 30 μS/cm max.). Eco-Vision designs and builds both mobile and fixed demin plants. We store the water from the paver washing tanks in a buffer tank. The wash water in this tank is pumped through parallel carbon and sand filters and then transferred to a second buffer tank. A cation and anion exchanger removes the last fractions of harmful materials and/or heavy metals from the wash water. The final step consists of UV irradiation to kill any bacteria. The resulting demin water is buffered in a tank before being pumped back into the washing system. These plants have capacities in the range of 1 to 30 m³/hr. The big advantage of such installations that they can reduce the discharge volume by 90% or more.

Zero Liquid Discharge using distillation

In some cases, wastewater volumes are limited and concentrations of polluting components are too high to percolate the water through ion exchangers. In that case, evaporation can be a good alternative. Evaporation uses distillation to purify the contaminated wash water, concentrating the contaminating components and reusing the pure distillate as wash water. The best solution is often a vacuum concentration system (vacuum distillation). The distillate in the vacuum pump is heated to a temperature of 120 °C, killing any germs and eliminating the risk of algal bloom in the recycled water. The residue can then either be discharged or undergo physico-chemical treatment in a DND system. This technique can be applied to degreasing baths, for the concentration of wash water streams, for the purification (desalination) of the filtrate from the DND system or for the recovery of cutting oil. This energy-efficient system has a wide range of applications. This solution can handle almost anything except for high concentrations of chlorides.

If wastewater streams with high concentrations of chlorides and/or fluorides and low pH values are nonetheless required, a system with a heat and vacuum pump is a good alternative. The water evaporates at 35°C in that case. Eco-Vision has partnered with H2O and Eco-Techno in the Benelux countries for the supply of these systems.

Membrane techniques

Eco-Vision uses a tailor-made membrane system for recycling large wash water streams in the pharmaceutical industry, in combination with extensive automation and data logging. This also offers several options to adjust the process.

The use of low fouling membranes significantly reduces the risk of deposits. If a CIP proves necessary, the necessary connection points are already available. The existing pumps can be used for the washing process without additional safety risks. The extensive logging module facilitates proper follow-up and process adjustments.

The result is an installation with a ‘pure water stream’ that can reuse up to 75% of the wastewater in the current process.

Conclusion

Currently Eco-Vision recovers 7,500m³ of wastewater on a daily basis using a combination of various sustainable recycling techniques. This is a huge volume that no longer needs to be discharged. We will gladly inform you about all the available options for your production process.