Profile: Panta Rei S.R.L specializes in designing and building water & waste water treatment plants. We are an ISO 9001:2000 certified company. We offer designing, assembling, and maintaining plants for industrial effluents. Our main membrane processes used in wastewater treatment are miltrofiltration, ultrafiltration, nanofiltration, and reverse osmosis. The influent to the membrane is known as feed stream or feed water. The water that passes through the semi-permeable membrane is known as permeate, and the liquid containing the retained constituent is known as concentrate.