Direct Membrane Treatment Of Anaerobic High Iron And Manganese Groundwaters

Historically there has been an industry-wide perception that if a feedwater source contains dissolved metals they must be removed via oxidation and filtration prior to RO membrane treatment. The purpose of this paper is to provide data on evaluating the suitability of directly treating high iron and manganese feedwaters with membranes through the presentation of several case studies. The Grimes, IA WTP was originally built to treat water from a shallow wellfield with lime softening and filtration for hardness and iron removal. After a drought in 2012/2013 the City decided to drill a deep well, approximately 2000 feet deep into the Jordan Aquifer. The City was interested in investigating reverse osmosis (RO) membrane treatment for this water source. The average iron level of the Jordan well was 2.3 mg/l and for the Shallow wellfield it was over 12 mg/l. A pilot study was performed to test membrane treatment suitability. The pilot study consisted of two phases: first, direct RO membrane treatment of Jordan well water; second, direct RO membrane treatment of a blend of the Jordan well and Shallow well feedwater. This paper will present the specifics of the Grimes project and provide technical recommendations for successfully directly treating feedwaters with high metals content. The first phase of full-scale implementation of the Grimes membrane plant has been completed and operational data will be presented. Brief examples of direct membrane treatment of high metals feedwater from several other plants will also be provided, along with information on their remarkably low cleaning frequencies and long membrane life.

This presentation is available to AMTA Members only.