Zero liquid discharge (ZLD) is an engineering approach to water treatment where all water is recovered and contaminants are reduced to solid waste.The focus of this system is to reduce wastewater economically and produce clean water that is suitable for reuse, thereby saving money and being beneficial to the environment. ZLD systems employ advanced treatment technologies to purify and recycle all of the wastewater produced. This includes pre-treatment and evaporation of the industrial effluent until the dissolved solids precipitate as crystals. These crystals are removed and dewatered with a filter press or a centrifuge. The water vapor from evaporation is condensed and returned to the process.
The purpose of the pretreatment program is to block the introduction of pollutants, which can cause damage to equipment and interference with the water treatment process. It also removes suspended impurities, solids, colloids and living organisms from raw water.
Filtration is the process of separating suspended solid matter from a liquid, by causing the latter to pass through the pores of some substance. Filtration collects the suspended impurities in water and enhances the effectiveness of disinfection.
IT is a water purification process that uses a partially permeable membrane to remove ions, unwanted molecules and particles from water. An applied pressure is used to overcome osmotic pressure, RO can remove many types of dissolved and suspended chemical species from water.
Vacuum evaporators, also know as wastewater evaporators, are one of the most effective technologies for the minimization and treatment of industrial wastewater. The evaporators work under vacuum, so the boiling temperature of the liquid effluent is lower; thus saving energy and improving efficiency.