LLOBREGAT RIVER WATER DIRECT ULTRAFILTRATION AND REVERSE OSMOSIS: OPERATIONAL AND OPTIMIZATION EXPERIENCES

摘要

An integrated membrane system consisting of DOW™ Ultrafiltration (UF) and FILMTEC™ ReverseOsmosis (RO) filters treating raw river water has been optimized by improving the operating sequenceand cleaning conditions. The combined membrane process treats challenging surface water fromLlobregat River (Barcelona, Spain) with occasional turbidity values higher than 1000 NTU. After twoyears in operation, the concept and feasibility of direct ultrafiltration of difficult waters has been provedand a significant optimization of the process has been achieved, resulting in a water yield or recoveryincrease from 87% to higher than 96%. It has additionally been demonstrated that DOW™Ultrafiltration outside-in PVDF systems can reliably operate despite the difficult incoming waters with alimited mechanical pre-treatment (consisting of a hydrocyclone and a ring filter) and their benefitsinclude constant and better filtrate quality and low chemical consumption when compared to aconventional treatment,. Good long term integrity of the fibers has equally been demonstrated throughfrequent integrity tests and on-line produced water quality monitoring. Permeate turbidity below 0.07NTU has constantly been measured by on-line measurements despite the very fluctuating feed waterturbidity.