Suspended solids are typically removed by mechanical and or chemical methods. Microfiltration commonly requires some treatment to remove large particles, and oil and organics that can affect filter production rates. The extent of total water treatment required depends on quality of the raw water and the disposition of the treated water. Total suspended solids (TSS) removal may often be sufficient treatment to meet a given target and satisfy key chemical performance criteria for water re-use for the formulation of hydraulic fluids.

This study explored the use of aeration and settling to reduce iron content of produced water prior to filtration with a 10-µm bag filter and with hollow fiber, stainless steel and ceramic filters of submicron porosity. It was determined that aeration with compressed air for sufficient time to oxidize the iron was an effective treatment to convert ionic iron to particulate iron oxide in a produced water sampled from an unconventional gas well in the Barnett Shale near Dallas in Arlington TX.

The 10-µm bag filtration proved inadequate for achieving any significant reduction of turbidity, particle count or iron reduction. However, the filters rated to remove particles smaller than one micron proved useful. A comparison of different submicron-rated filters, comprising hollow fiber, stainless steel and ceramic membranes, all capable of removing particles greater than 1 µm when used in the treatment of mixed aerated water and settled aerated water, showed no major difference in their gross performance of TSS reduction or their ability to remove iron oxide particles. All the submicron filters reduced the water turbidity and particle count by more than 90% and reduced total iron to a concentration that was below detection limit.

You can access this article if you purchase or spend a download.