The use of spiral wound membranes for treatment of brackish groundwater sources has gained
widespread acceptance. This technology, however, is not without operational difficulties, one of
which is membrane fouling. Groundwater supplies in the province of Saskatchewan, Canada
are typically very hard, laden with iron, manganese, and often organic carbon and ammonium.
Fouling through scaling can be controlled with antiscalant chemicals and recovery but typically
some form of pretreatment is required to reduce the constituents that cause colloidal and
biological fouling.
Biological filtration prior to membranes has been implemented in some small First Nations water
treatment systems in Saskatchewan. The stepwise filtration process targets iron, arsenic,
ammonium and organic carbon to reduce these constituents as they can be used as an energy
source for bacteria that may populate and foul the membrane elements. This process also
reduces the potential for colloidal fouling by oxidized iron and manganese as chemical oxidants
are not used. The water produced by the membranes exhibits a very low chlorine demand due
to the removal of readily oxidized species. By limiting reliance and demand on chemicals for
treatment of the water to only low dosages of membrane antiscalant and chlorine, the First
Nation communities have gained a consistent, sustainable, and environmentally friendly method
of treating their drinking water, with reduced costs and complications of utilizing chemicals to
oxidize and remove potential foulants.
The initial installation of this process at the Yellow Quill First Nation was a green-field
construction using a water source previously thought unfeasible to treat economically. Building
on the success of the Yellow Quill project, an existing manganese greensand process at the
Pasqua First Nation was retrofitted to provide biological iron, arsenic, and ammonium reduction
followed by membrane treatment to provide higher quality water to the First Nation residents
there. The process capacity was similar to the Yellow Quill process but was provided as a plant
retrofit within the existing building footprint at Pasqua, at a fraction of the construction cost of the
Yellow Quill process. The paper describes the development of the process, types of water it is
suitable for, issues encountered, retrofit considerations and the logistics surrounding the
process conversion. Cost implications of these processes are also described. Includes 12 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 8.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 47 |
| Published : | 06/01/2007 |
