Water Resources Research Act Program

Details for Project ID 2020OK197B

A new dolomite filtration technology to remove heavy metals and NORM from produced water

Institute: Oklahoma
Year Established: 2020 Start Date: 2020-03-01 End Date: 2021-02-28
Total Federal Funds: $25,000 Total Non-Federal Funds: $50,025

Principal Investigators: Javier Vilcaez

Project Summary: In order for produced water to be successfully integrated into industrial and agricultural uses, produced water needs to be treated not only for salinity (NaCl) but also for heavy metals and naturally occurring radioactive materials (NORM). Currently, the use of membrane technologies are not economically competitive options to remove heavy metals and NORM from produced water. The proposed research falls in the Water Technology and Innovation category. The objective is to determine the economic and technological potentiality of a new dolomite filtration technology to reduce the cost and/or replace to use of membrane technologies to remove heavy metals and NORM from produced water. The proposed dolomite filtration technology consists of columns made of high purity compressed powdered dolomite. Here, dolomite works as sorption medium for heavy metals and NORM, and polymer and/or large hydrocarbon molecules (n-alkanes) trapped in small pore troths work as filtration medium for heavy metals and NORM. This technology is based on the PI’s recent findings regarding the higher Ba sorption levels attained in dolomites (collected from the Arbuckle Group in Oklahoma and Kansas) than in clay (kaolinite) bearing sandstones, as well as on the mechanical properties of dolomite filters made of compressed powdered dolomite to trap polymers (guar gum) which has been found to enhance the removal of Ba from produced water. The proposed approach consists of experimental and computational studies. Specifically: 1) batch experiments will be conducted to assess the sorption of heavy metals and NORM (Ba, Sr, Pb, Cr, and U) on dolomites, 2) core-flooding experiments will be conducted to assess the transport and removal of heavy metals and NORM, as well as the transport and trapping of polymers (guar gum and xanthan gum) and n-alkanes through compacted dolomite filtration columns, and 3) numerical models will be established to design optimum dolomite filtration operations, and/or asses the feasibility of using this new economic technology in combination with conventional membrane technologies to remove heavy metals and NORM from produced water. Our positive outlook on the feasibility of such approach is based on the following scientific and practical considerations: 1) dolomites represent a superior sorption capacity for heavy metals contained in high salinity waters than other natural sorption materials, and 2) high purity dolomites are abundant in the Arbuckle Group of Oklahoma and Kansas.