Effluents treatment

Depending on the type of effluent, the optimal solution varies. Condorchem Envitech has an expert team in the analysis, design, construction and commissioning of plants for the treatment of effluents adapted to the needs of each customer.

By using various technologies, or a combination of them, any industrial effluent can be treated effectively. Depending on the features of each case, the effluent treatment system will be more or less simple.

More and more industries are deciding to take a step forward when treating their effluents and, considering that water is a scarce resource with an important environmental and social value, are now opting for a treatment system based on the concept of “zero discharge”. This allows for total recovery and reuse of the water content of the waste effluent, in addition to producing the minimum amount of solid, dry waste.

Thus, besides being a necessity for any environmental and socially responsible industry, effluent treatment via a zero discharge system has a long list of advantages:

• Reduction of the environmental impact.
• Assumption of environmental and social responsibilities.
• Compliance with environmental regulations.
• Reduction in discharge taxation for the final effluents.
• Financial savings from possible administrative fines for non-compliance with environmental regulations.
• If there is reuse, reduction in the use of a scarce resource, with the consequent financial savings.
• If there is reuse, increase in the guarantee of supply of an essential product.

Once the situation has been analyzed, it can be quickly concluded that, whatever the case may be, it is highly advisable to adopt the necessary measures for effluents to be treated efficiently and economically, if possible.

At Condorchem Envitech, we consider effluent to be liquid waste difficult to purify or recycle by traditional methods (physical, chemical or biological purification) due to its composition and special danger if discharged. We have different evaporation and distillation technologies designed to obtain the maximum concentration of waste when treating these effluents.

It is important to note that, on many occasions, companies choose to store and send these effluents to waste managers; but there are cases where treatment at their own premises can provide significant long-term financial savings and extra income from the sale of by-products obtained after treating the effluent.

We have the best technologies available today for the treatment of effluent, among which are:

• Vacuum evaporators
• Crystallizers.
• Reverse osmosis.
• Microfiltration, ultrafiltration and nanofiltration.
• Biological purifiers.
• Physicochemical treatment plants.
• Ion exchange resins.
• Electrodeionization.

Normally, production processes use water for numerous purposes: incorporation in the final product, washing equipment, cleaning facilities or refrigeration, for example. As a consequence, a liquid effluent is obtained that must be treated before discharge to comply with restrictive environmental regulations. The effluent composition and its production profile will lead to a selection of different solutions that could be effective and viable.

The variety of liquid effluents that can be produced by industrial processes is practically endless, although these can be grouped according to their composition. The main types of effluents to which Condorchem Envitech can deal with are the following:

• Effluent with a high organic load: This is the case, for example, with a large number of food sector industries (e.g. production of ice cream, cheese making and dairy products), the livestock sector (e.g. slaughterhouses and meat industries) and the wine sector.
• Effluent with a high nutrient load (nitrogen and/or phosphorus): These are effluents from the glass industry and, especially, with cattle droppings.
• Effluent with toxic compounds: Some of the effluents from the mining industry, some chemical industry washing water and surface treatment belong to this group.
• Effluent with brine or a high salt content: This comes from food industry production processes (e.g. canning, pickling and salting) and in the reject effluent of operations with membranes, generally, from reverse osmosis units.
• Effluent with oily emulsions: This group includes waters contaminated by hydrocarbons, from the metal-mechanical industry, galvanic process rinse waters and surface treatment, for example.
• Effluents with heavy metals: This is the case for effluent from mining, paint production, surface treatment, metal-mechanical industry and tanning of skins, for example.
• Effluents with color: This basically corresponds to effluent from the textile and leather tanning industries.
• Complex effluent: This type includes all those effluents where, due to their features, conventional treatments are not viable. They usually have an indefinite and variable composition. For example, this is the case with leachates produced from municipal solid waste landfill.

The composition of industrial effluent and its possible variability are determining factors when deciding which process can provide effective treatment. The most commonly used are the following:

• Aerobic biological treatment (with free or immobilized biomass): Generally used to treat effluents with a moderate organic load and high flow rates.
• Anaerobic biological treatment (with free or immobilized biomass): Especially suitable for waters with a high organic content and moderate or low flow.
• Homogenization and neutralization with acid or alkali: This process is necessary when the effluent composition variability is very high or when it is desired to modify the effluent pH.
• Flocculation-coagulation: This is useful when removing suspended contaminants from the effluent when they are difficult to settle.
• Flotation: Especially useful for the separation of oils and fats that have not formed an emulsion.
• Precipitation: This is suitable when one or more solubilized compounds precipitate to the bottom of a container after the addition of a compound or a change in environmental conditions.
• Decantation: This is to separate the solids in suspension contained in the effluent or those formed as a consequence of a desired precipitation.
• Filtration: Suitable for the separation of solid material contained in the effluent.
• Membrane technologies (microfiltration, ultrafiltration, nanofiltration and reverse osmosis): Useful processes for separating the effluent from very small particles. Microfiltration separates particles of a size between 0.1 μm and 10 μm (e.g. bacteria, very fine coal dust and asbestos). Ultrafiltration membranes retain particles with a size between 1 nm and 100 nm (0.1 μm). This is the size of a virus, colloid, macroprotein or endotoxin, for example.While microfiltration and ultrafiltration separate suspended particles from the liquid, molecules dissolved in the liquid (e.g. sugars, proteins and dye molecules) can be separated by nanofiltration. Nanofiltration membranes have a cut-off value of between 0.1 nm and 1 nm, which is the typical size of most molecules that do not have a high molecular weight.

  Finally, reverse osmosis allows ions of a very small molecular size, such as the chloride ion, to be separated from the effluent.

• Ionic exchange: This process retains certain ions very selectively, which allows for demineralizing or softening an effluent or retaining radioactive ions present in the effluent.
• Vacuum crystallization and evaporation: These processes are especially useful for treating complex effluents (e.g. strong salt concentration, indefinite composition, presence of toxic compounds and oily emulsions) or when it is desired to minimize the discharge of the liquid effluent.
• Membrane distillation: A useful process when it is desired to selectively separate a usually corrosive compound or contaminant from the effluent.