WASTEWATER TREATMENT PROCESS AND APPARATUS FOR HIGH FLOW IMPURITY REMOVAL

摘要

A process and system for removing heavy metals, fluoride, silica and other contaminants from large volumes of wastewater is disclosed. In the process, a wastewater stream containing the contaminant is treated with a chemical coagulant to create a particle having a diameter greater than 5 microns. Treated wastewater is passed through a microfiltration membrane which physically separates the metal contaminant particle from the wastewater. Commercially available microfiltration membranes having a pore size from 0.5 micron to 5 microns may be used. The treated wastewater flow rate through the microfiltration membranes can range from 700 gallons per square foot of membrane per day ("GFD") to 1500 GFD for metal contaminants and from 140 GFD to 600 GFD for silica contaminants. Solids are removed from the membrane surface by periodically backflushing the microfiltration membranes and draining the filtration vessel within which the membranes are located. The dislodged solid material within the filtration vessel is flushed into a holding tank for further processing of the solids.