MIXED TECHNOLOGY SYSTEMS
Industrial wastewater treatment plants that use mixed specialised technologies combine several treatment processes to address the complexity and variability of industrial wastewater. These integrated systems are designed to remove a wide range of contaminants, including suspended solids, organics, heavy metals, nutrients and pathogenic microorganisms, ensuring that the treated water meets the required quality standards for discharge or reuse.
Why use mixed technologies?
Industrial wastewater is often characterised by:
Variable composition: depending on the industrial process, they can contain organic and inorganic substances, metals, solvents, etc.
High concentration of contaminants: some wastewater has very high pollutant loads.
Presence of recalcitrant substances: compounds that are difficult to degrade with a single treatment.
Stringent regulatory requirements: environmental regulations often require advanced treatment to reduce the impact on the environment
Main components:
1. UV exposure chamber: a reactor in which water flows while being exposed to UV light.
2. UV lamps: ultraviolet light sources, usually low-pressure or medium-pressure mercury.
3. Control and monitoring system: regulates the intensity of the lamps and monitors the UV dose delivered.
4. Automatic cleaning system: to keep the quartz glass protecting the lamps free from encrustations or deposits.
5. Power supply: to provide energy to the UV lamps.
Advantages of mixed technologies:
High efficiency: each technology deals with specific contaminants, guaranteeing a complete treatment.
Flexibility: it can be adapted to different types of industrial wastewater.
Cost reduction: the combined use of technologies can optimise energy consumption and operating costs.
Regulatory compliance: meets legal requirements for water discharge or reuse.
Sustainability: promotes water reuse and reduces environmental impact.
Applications:
Here are some common combinations of technologies used in industrial wastewater treatment plants:
1. Pretreatment + Biological + Membrane
Pretreatment: removes suspended solids, fats and oils through processes such as screening, grit removal or flotation.
Biological treatment: uses micro-organisms to degrade organic substances (e.g. activated sludge, membrane bioreactors - MBR).
Membrane treatment: reverse osmosis (RO) or ultrafiltration (UF) remove dissolved substances, salts and micro-organisms.
Applications: food, chemical and pharmaceutical industries.
2. Chemical-Physical + Ion Exchange + UV
Chemical-physical: coagulation, flocculation and sedimentation to remove suspended solids and heavy metals.
Ion exchange: removes specific ions (e.g. heavy metals, nitrates) through resins.
UV disinfection: inactivates pathogenic microorganisms without the use of chemicals.
Applications: Metallurgical, textile and galvanic industries.
3. Biological + Ozone + Active Carbon
Biological treatment: degrades biodegradable organic substances.
Ozone (O₃): oxidises recalcitrant organic substances and disinfects water.
Active carbon: adsorption of residual organic compounds, chlorine and odours.
Applications: Chemical, petrochemical and paper industries.
4. Evaporation + Crystallisation
Evaporation: removes water in the form of vapour, concentrating the contaminants.
Crystallisation: separates salts and dissolved solids in the form of crystals.
Applications: Industries with high salinity wastewater or containing non-biodegradable substances.
5. Filtration + Electrocoagulation + UV
Filtration: removes suspended solids through sand, activated carbon or membrane filters.
Electrocoagulation: uses electric current to remove heavy metals, colloids and organic substances.
UV disinfection: guarantees the absence of pathogenic micro-organisms.
Applications: Metallurgical, textile and surface treatment industries.
Challenges and considerations
Design complexity: requires careful design to properly integrate the different technologies.
Initial costs: the initial investment can be high, especially for advanced technologies such as reverse osmosis or evaporation.
Maintenance: each technology requires specific maintenance, which can increase operating costs.
Wastewater management: some processes (for example, evaporation or ion exchange) generate concentrated wastewater that must be disposed of correctly.
Conclusions
Plants with mixed specialised technologies are the ideal solution for treating complex industrial wastewater. By combining several processes, it is possible to obtain high quality treated water, reduce environmental impact and optimise operating costs. The choice of technologies should be based on the characteristics of the wastewater, regulatory requirements and the company's sustainability objectives.