National City Well Iron and Manganese Treatment System

National City, CA


The Sweetwater Authority in southern San Diego County sought to remove color from the drinking water within the National City area, which was caused by iron and manganese in three major supply wells. PACE completed a 3-month pilot project using five different treatment trains for oxidative filtration. The train consisting of “Greensand Plus,” or manganese dioxide-coated sand, achieved treatment consistently to less than 5 parts per billion. By removing iron particles about 0.45 micrometers in size, accumulation in the drinking water system in National City will be substantially reduced. The system includes backwash recovery to save water loss from backwash. The full-scale design integrates the proposed final treatment system into the existing site with a new booster pump skid and on-site water quality analyzers. PACE also provided drinking water permitting and approval assistance.


Key Features:

  • Concept design development and pilot testing for optimal iron and manganese removal system
  • Plans, specifications, and estimates (PS&Es) of “Greensand Plus” treatment system, new booster pump skid, and on-site water quality analyzers
  • Drinking water permitting and approval assistance

Sweetwater Authority

Advanced Water Quality / Piloting, Water Treatment