Vacuum evaporators have proved to be one of the most efficient technologies for wastewater treatment. Condorchem Envitech has designed and installed more than 250 vacuum evaporation plants all over the world, performing great environmental and economic results. See our references.
Vacuum evaporation consists of reducing the interior pressure of the evaporation chamber below atmospheric pressure. This reduces the boiling point of the liquid to be evaporated, thereby reducing the heat necessary/eliminated in both the boiling and condensation processes. In addition, there are other technical advantages such as the ability to distill other liquids with high boiling points and avoiding the decomposition of substances that are sensitive to temperature, etc.
Keeping in mind that evaporation is a system of separation, the presence of three distinct fluids are verified: Feed, Distillate, and Concentrate.
Feed: The fluid entering the evaporator. This is typically water contaminated with diverse inorganic and organic products, solids in suspension, etc. In some cases, a pretreatment is required, which may consist of thick solid filtration, decantation, neutralization or adjustment of pH when necessary, etc.
Distillate: Is the fluid obtained from evaporation that has transformed from vapor to liquid. The water is more or less pure, free of salinity. However it may be contaminated by the presence of volatile substances that have evaporated together with the water. Depending on the final destination of the condensed water, recycling is recommended or proper discharge. This final water treatment is accomplished by absorption-adsorption systems, membrane separation and others, in order to obtain ultrapure water if needed or dischargeable according to Table III.
Concentrate: This is the final residual product, i.e. the balance between the distillate and the feed. Generally, a reduction of entry volumes by 10 or 15 times is achieved; it is possible to obtain dry residuals with special equipment. In some cases it is possible to recover this concentrate as raw material. In other cases it will be transferred to the appropriate sector for treatment. Generally, the recommended treatment for this waste is incineration or its recovery as fuel in cement kilns firms. There exist sectors specializing in treatment or disposal that are low cost. It is also possible to transfer such waste to deposits or special landfills due to its low water content. Whatever the case, the enormous reduction of waste makes it a very profitable investment by the savings in expenses represented by transfer costs and traditional disposal centers.