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 greenfield
construction using a water source previously thought untreatable. 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. This paper
describes the source water conditions and the process and the benefits of using biological filtration to
pre-condition the water upstream of the reverse osmosis membrane filters. Includes 9 references, tables, figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 6.8 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 52 |
| Published : | 06/01/2007 |
