Zero Liquid Discharge
When the client desires to comply with certain company policies or local regulations requiring him to avoid any final discharge, a series of treatments need to be considered in order to recycle the water and dispose of the residual matter.
First of all, Panta Rei provides a proper biological treatment in order to carry out the degradation and reduction of the main pollutants such as BOD, COD and suspended solids. Following this, a filtration and preliminary treatment stage is set. Then, a membrane treatment follows the process line. The first section is made of an ultrafiltration treatment to guarantee a fine removal of the suspended solids and protect the following membrane treatment steps.
Afterwards, the nanofiltration section performs the color removal, while rejecting also some bivalent components such as calcium and sulfates, reducing the hardness and sulfate concentration of the effluent.
Finally, a reverse osmosis section reduces the total dissolved solids concentration and all the residual pollutants in order to produce a high quality water whose characteristics make it suitable to be reused in the dyeing process, the boilers or any other application requiring high purity water.
It is possible to configure the reverse osmosis stage in order to obtain a larger recovery percentage, which ranges from 60 to 92 percent according if one, two or three steps are installed. Panta Rei provides a process analysis to determine the cost and benefits as a function of the recycled water amount, capital cost and power consumption. We can treat the reject of the reverse osmosis membranes with natural, multi-stage or vacuum evaporators in order to close the zero discharge process loop and thus guarantees full compliance with the most constringent environmental law.