Pella Reverse Osmosis Water Treatment Plant Well Design

Faced with increasing nitrates in their Des Moines River alluvial water source and slow depletion of the alluvium, the City of Pella needed to develop a facility plan to identify required improvements. The improvements included implementing new reverse osmosis (RO) treatment facility to treat Jordan aquifer well water while integrating it within their existing lime softening treatment facilities.

The facility plan also identified necessary improvements to the existing lime softening plant to extend its useful life another 20 years and improvements needed to integrate it with the new reverse osmosis treatment facility.

After completion of the facility plan, the City of Pella implemented the design of a new RO treatment facility to be incorporated into the City’s existing lime softening treatment facility. The new RO treatment facility operates in parallel with the existing lime softening plant and consists of a new Jordan aquifer well, three RO treatment trains, bypass treatment aerators and detention tank, a permeate aerator, antiscalant storage and feed system, caustic storage and feed system, and hypochlorite storage and feed system.  Rehabilitation of existing gravity filters and an existing 4 MG clearwell, as well as associated raw water piping and RO concentrate waste piping, was also completed. The design also repurposed a portion of the existing treatment plant building, not currently utilized, except for general storage and vehicle parking.