El Toro Water District Disinfection System Improvements

Laguna Hills, CA


The El Toro Water District (ETWD) existing 2MG and 3MG potable water tank reservoirs had difficulty with chlorine residual due to temperature stratification. ETWD contracted PACE to design new tank mixing systems with a residual sampling system, a liquid chemical injection system and storage facility, and a new building with automation and site security. Civil, mechanical, electrical and controls design plans, specifications, and cost estimates will be produced for construction.


PACE evaluated numerous mixing equipment manufacturers and ranked each manufacturer based on several criteria including capital cost, mixing rate, and energy consumption. The tank mixer chosen is an external pump, which is easily accessible when the system requires maintenance. The high mixing rate of 7,500 gpm mixes the tank within 12 hours, and features built-in chemical monitoring.


PACE provided calculations for disinfection storage requirements, as well as a process flow diagram for routing of flows of water, chemicals, analyzer lines, and the flow for mixing. The 300 SF liquid chemical storage facility houses a 500-gallon Ammonium Hydroxide tank and a 2,000 gallon tank for Sodium Hypochlorite.


Key Features:

  • Designed new storage facility
  • New building with automation and site security
  • Provided calculations for disinfection storage requirements
  • Liquid chemical injection system
  • Residual sampling system
  • New tank mixing systems

El Toro Water District

Water Infrastructure