© 2019 by LEE & RO, Inc.

Water Treatment


Mills Water Treatment Plant Rehabilitation & Upgrading
Metropolitan Water District of Southern California

Los Angeles, CA

LEE & RO provided condition assessment, engineering and design services for a $45 million rehabilitation and upgrading project. The project consisted of (1) Chemical Systems Improvements covering sulfuric acid, hydrogen peroxide, caustic soda, alum, ferric chloride, Poly-DADMAC, sodium hypochlorite, aqueous ammonia, chlorine, and dry polymer; (2) Treatment Module 1 & 2 Rehabilitation  involving replacement of flocculators and clarifier traveling bridge sludge collector drive mechanisms and other mechanical equipment, structural repairs, modifications of piping and valves, and upgrading of electrical and controls systems; and (3) Single Point Chemical Injection System which is to enhance coagulation and be installed on the 144-inch diameter ozone contactor effluent pipe prior to the flow-splitting to Clarifier Modules 1 through 4.  The 51.5 mgd capacity Module 1 and 54.5 mgd Module 2 were removed from service in 1997 and these projects will restore the Mills Plant to its full 326 mgd capacity.

Electro-Dialysis EDTReversal (EDR) Demineralization Facility Expansion

North City Water Reclamation Plant

City of San Diego

San Diego, CA


The City of San Diego produces 5.5 mgd of 300 mg/l TDS water utilizing General Electric’ EDR units and produces up to 12 mgd of recycled water by blending.  LEE & RO designed new EDR units and other facilities to house the future Advance Water Treatment pilot plant.  The new EDRs required expansion of the existing infrastructure including piping & valves, electrical & controls, and structures.  The $2.5 million project also included new vertical turbine feed pumps with VFDs, new electrical building, new duct banks, and power feeders.


Washwater (WW) System Improvements

Earl Schmidt Filtration Plant (ESFP)

Castaic Lake Water Agency

Santa Clarita, CA



The 56 mgd ESFP consists of an ozone injection, clarifiers, and filters.  WW from the clarifiers and filters are pumped to the WW treatment facilities and solids are treated in a gravity thickener, and dewatered in the drying beds.  WW return system consists of storage basins, chemical conditioning, and treatment units. The Calif. DPH Cryptosporidium Action Plan includes a 2 NTU recycled water turbidity limit and regulates the total recycle water flow to be less than 10% of the plant flow.  The current WW system prevents maximizing the WW recycle flow up to 10% and cannot reduce turbidity less than 2 NTU.  LEE & RO prepared process analysis and designed a $7.5 million project which will add WW storage basins with an automatic sludge scrapper system and floating decanters, thickeners, and drying beds with electrical, and site improvements. 


Goldsworthy Desalter Project

Water Replenishment District of Southern California

Torrance, CA

LEE & RO provided engineering, design, and construction phase engineering services for a $12 million, 2,100 gpm capacity desalter project.  The project objectives were to restore the fresh water aquifers by removing trapped seawater plumes and to demineralize groundwater and pump it to the CAL Water and City of Torrance domestic water distribution systems. The project elements included groundwater extraction wells and pump stations, reverse osmosis (RO) process feed pumps, RO product water pumps; RO modules, chemical systems; pipelines for transporting raw water, treated water and brine. Brine is discharged to the County Sanitation District’s trunk sewer.


Chemical Tank Farms and Chemical Injection Systems

at Diemer, Skinner & Weymouth Water Treatment Plants

Metropolitan Water District of Southern California

Los Angeles, CA

LEE & RO provided engineering, design, and construction phase engineering services for three large chemical tank farm and chemical injection system projects supporting the Skinner, Weymouth and Diemer Oxidation Retrofit Program (ORP) projects.  The ORP projects remove THM forming compounds via ozonation. The major ORP project components are liquid oxygen storage, ozone generators, ozone contactors, spent ozone destruction system, and chemical systems.  The projects included storage tanks and tank farms, leak containment structures and drainage, metering pumps and piping, controls & SCADA, and electrical systems for caustic, sulfuric acid, aqueous ammonia, hydrogen peroxide, sodium hypochlorite, alum, ferric chloride, and polymers. The construction cost for the tank farm at each plant is approximately $8 million.

Washwater Reclamation Plant Upgrading

Skinner Water Treatment Plant

Metropolitan Water District of Southern California

Los Angeles, CA


LEE & RO provided engineering, design, and construction phase engineering services for a $7.5 million washwater upgrading projects at the 600 mgd capacity Skinner WTP.  The project included replacement of nine horizontal flocculators with 18 vertical hydrofoil flocculators, replacement of tube settlers and launders, associated structural and electrical systems and motor control centers.  Construction was staged to allow at least two of the three treatment trains to be in operation at all times.  The project also included upgrading of water quality monitors housed within six concrete monitoring vaults.  Upgrading was needed to accommodate additional online monitors, such as turbidity analyzers, pH meters, and particle counters to comply with more stringent EPA requirements.


Bulk Chlorine Containment & Injection Facilities

at Skinner, Jensen and Mills Water Treatment Plants

Metropolitan Water District of Southern California

Los Angeles, CA

LEE & RO provided engineering, design, and construction phase engineering services for three large bulk chlorine storage and feeding facilities at the Skinner, Jensen and Mills Water Treatment Plants.  The total construction cost for the three facilities was $57 million.  Liquid chlorine is delivered in either 90-ton railcars (at Jensen) or 19-ton cargo trailers (at Skinner and Mills).  The project included new bulk chlorine storage building (divided into storage bays housing railcars or cargo trailers and new equipment rooms for evaporators, chlorinators, and electrical), leak detection, emergency ventilation and chlorine scrubber, chlorine ejectors, and water piping.  Each facility required careful sequencing of construction including temporary facilities to maintain the existing plant in operation.  The Jensen facility included considerable rail yard improvements including new tracks, switches and turnouts.  LEE & RO provided technical support during the startup and commissioning phase.


Bowman Water Treatment Plant Sodium Hypochlorite Disinfection Conversion Project
Placer County Water Agency

Auburn, CA

LEE & RO provided engineering, design, and construction phase engineering services for a $1.5 million project, converting gaseous chlorine to liquid sodium hypochlorite disinfection at the 5 mgd water treatment plant.  The new hypochlorite facilities, including two 2,000 gallon storage tanks, five metering pumps, feed piping, and electrical and control systems, were installed including upgrades to safety features such as ventilation, eye washing, and lighting.  Work also included programming and integration to the existing SCADA system and miscellaneous structural and piping modifications.

Edward C. Little Water Recycling Plant Phase III Expansion 

West Basin Municipal Water District

Carson, CA


LEE & RO prepared a design-build procurement package with 35% design documents and provided construction support services for the $17 million, Phase III Expansion Project consisting of additional microfiltration (MF) and reverse osmosis (RO) treatment trains.  This project was to supply 5 mgd of recycled water from Hyperion Wastewater Treatment Plant secondary Effluent for cooling systems at the Chevron El Segundo Refinery.  The project included a surge control facility, micro-strainers, MF feed pumps, MF units, RO feed pumps, RO trains, decarbonators, product water wells, low and high pressure product water pump stations, and electrical and instrumentation.  The project also included chemical storage & feed systems (hypochlorite, bisulfite, sulfuric acid, and MF cleaning agents).


Engineering and Project Management Support Services for Groundwater Well Field and Plant Expansion

City of San Diego

San Diego, CA

LEE & RO is providing engineering and project management oversight during the design and construction phases to preserve the City of San Diego’s interest in this $28 million project, which consists of five new groundwater wells, pipelines, and expansion of the RO system at the Reynolds Groundwater Desalination Facility.  The five new wells will pump raw brackish water from the underground San Diego Formation Aquifer 800 feet below grade.  The raw water is then pumped via 8-inch and 12-inch piping several miles away to the desalination facility where it is treated through reverse osmosis. The new wells and expansion of the facility will increase the potable water production from 5 mgd to 10 mgd.  This is a Sweetwater Authority project, but the City of San Diego is responsible for 25 percent of the construction cost since the aquifer water is a shared resource between the two parties. 


Chloramine Disinfection Conversion Projects

Los Angeles County Department of Public Works

Alhambra, CA

LEE & RO provided engineering, design, and construction phase engineering services for an $8.5 million Chloramine Disinfection Conversion Project which converted existing chlorine disinfection into chloramine disinfection for 18 separate production water well sites located in the Antelope Valley.  Each site was retrofitted with ammonia and chlorine gas storage (either one ton cylinders for large systems or 150 pound cylinders for small systems) complete with associated ammonia feed and chlorination systems.  Sites with chlorine ton cylinders are equipped with chlorine containment, and chlorine scrubbing systems. 

Earl Schmidt Filtration Plant

Ammonia System Improvements

Castaic Lake Water Agency
Santa Clarita, CA

LEE & RO evaluated the ammonia unloading area and site drainage at the treatment plant and a treated water reservoir located near the Castaic Lake.   We provided design for an ammonia containment system with a monolithic-pour secondary containment with chemical resistant coating, double wall piping, sump pump 7 discharge and electrical/controls.  The project also included an HACH 6000 chloramine analyzer along with a sampling system connected to the 48-inch treated water reservoir inlet.


Colorado River Aqueduct (CRA) Radial Gate Refurbishment Project

Metropolitan Water District of Southern California

Los Angeles, CA


LEE & RO provided field condition assessments, replacement/ refurbishment concept development, preliminary engineering and final design services for eight (8) large hydraulic radial gates along the CRA. The gates have been in operation since the CRA was commissioned in 1941.  The inspections revealed various stages of deterioration, corrosion, seal failures, and water leakages.  The size of the gate openings   vary from 11 feet x 14 feet to 22 feet x 12 feet and individual gate size is as big as 12.5 feet x 11 feet.  Five out of eight gates are double-leaf type.  This $8 million project was designed to enhance the CRA’s water supply reliability.  The design included extensive structural rehabilitation to accommodate the new gates into the existing structures and replacement of motor operators and electrical and control systems including SCADA systems.