FACTORS AFFECTING ENERGY EFFICIENCY OPTIMISATION IN A UF MEMBRANE PLANT
Courtis, B., Franklin, B., Pilkington, D.,
Earth Tech Engineering Ltd, UK
(free)
With increasing numbers of membrane treatment plants throughout the world, rising energy
costs and associated climate change concerns, there is a need to optimise energy
consumption associated with membrane filtration.
During commissioning a monitoring exercise was undertaken to record and evaluate losses in
membrane permeability between chemical cleaning cycles at Lough Owel WTW in the
Republic of Ireland. The results from this survey were used to construct a model to investigate
the optimisation of energy consumption for varying numbers of primary membrane racks in
operation and at different plant throughputs.
The results of the modelling exercise indicated that significant energy savings could be
achieved by optimally configuring flux rates and numbers of primary membrane racks in
service.
Introduction
There are increasing numbers of microfiltration (MF) and ultrafiltration (UF) plants throughout
the world treating potable water, driven both by water quality directives and the increasing
cost effectiveness of membrane treatment process. The operation of these plants often
includes significant pumping costs associated with the membranes and ancillary equipment.
Energy efficient operation at water treatment plants is being driven both by increasing energy
costs and concerns related to global warning.
This paper aims to investigate the variables associated with optimising the operation of
MF/UF membrane plants with respect to energy efficiency. The major energy consumption
elements associated with the operation of a membrane process elements can be categorised
as follows:
1. Pumping energy associated with the filtration of water through the membrane.
2. Pumping energy associated with periodic backwashing of the membranes.
3. Pumping energy associated with the periodic chemical cleaning of the membranes
and subsequent neutralisation of chemical waste water.
