© 2019 by LEE & RO, Inc.


Treatment and Recycling


Southside Plant Improvements and

Electrical System Upgrades

J. B.  Latham Wastewater Treatment Plant (JBLWTP)

South Orange County Wastewater Authority 

LEE & RO provided condition assessment, preliminary engineering, final design, and construction support services for a $14 million plant improvements at the 13 mgd capacity JBLWTP.  The project consisted of power supply upgrades, enhanced primary coagulation, rehabilitation of 13 rectangular secondary clarifiers, and structural concrete rehabilitation.  A new electrical building was constructed to house new switchgear and motor control centers (MCCs) which supplies power to 3 existing MCCs and 4 new MCCs. New duct banks, conduits, and electrical feeders were constructed throughout. The enhanced primary treatment project included a ferric chloride storage tank, metering pumps, and polymer system.  A new chain & flight sludge collector with 316 SST shaft and SST launders with FRP weirs were installed in 13 secondary clarifiers.  Also 316 SST slotted skimmers and telescoping valves were installed. The mixed liquor isolation gates were replaced with 316 SST downward opening slide gates. Throughout the plant failing and spalled concrete were reconstructed to the original lines and grades with casted new imbeds and coating.


Wastewater Treatment Plant (WWTP) Upgrades

City of Brawley

Brawley, CA

LEE & RO provided process analysis, engineering, design and construction management & resident engineering services for a $25 million plant upgrading project for the 5.9 mgd WWTP.  Prepared project reports, which led the City to successfully obtain $15 million from the CWSRF and a $10 million ARRA grant.  Project components included an activated sludge complete with nitrogen removal, UV disinfection, and sludge dewatering / drying.  The solids train consists of gravity thickening, centrifuge dewatering, and solar greenhouse drying.  The ARRA grant was partly based on the energy-saving, solar greenhouse for production of Class A Biosolids.  This project received “Project of the Year” award from the San Diego / Imperial County Chapters of the American Public Works Association in 2012.


Wastewater Treatment Plant Expansion & Improvements

Valley Sanitary District

Indio, CA

LEE & RO provided process analysis and plant master plan and prepared plans & specifications, and construction management & resident engineering services for a $46 million plant expansion and improvements that was implemented in two phases.  The $26 million Phase 1 Project increased the activated sludge capacity from 5 to 10 mgd, and added hypochlorite/bisulfite chlorination & dechlorination, 54 inch outfall, belt-press sludge thickening & dewatering, and drying beds.  The $20 million Phase 2 Project added two primary clarifiers, anaerobic digestion with a gas management system, odor controls, and admin & laboratory buildings.  Projects included extensive electrical work.


Headworks and Grit System Improvements

Point Loma Wastewater Treatment Plant (PLWTP)

City of San Diego

San Diego, CA

LEE & RO provided studies, engineering, design and construction phase services for a $22 million major upgrading at the 240 mgd PLWTP.  LEE & RO constructed two physical models (for the headworks and aerated grit removal tanks) and conducted tests to find ways to optimize the flow distribution to grit tanks and determine efficient grit tank cross-sectional configuration.  The project includes modifications to flow distribution channels, reconfiguration of the south aerated grit tank, addition of a new two-story grit dewatering building, and modifications to the odor control system.  The new grit dewatering building is 40 feet wide, 140 feet long and 49 feet high and houses 7 SlurryCup grit separators/grit washers, 7 grit storage bins, an electrical room, foul air fans, and a grit trucking facility.  A temporary grit building was constructed to facilitate construction. Extremely congested site with heavy water bearing concrete channels required extensive constructability analysis.


Wastewater Treatment Plant Phases 1, 2, and 3

Expansion and Upgrading Projects

City of Patterson

Patterson, CA

LEE & RO has provided planning, engineering, design and construction management / resident engineering services for plant expansion and modification projects which is being implemented in three phase.  The $5 million Phase 1 increased the plant capacity from 0.5 to 1.3 mgd in 2003 and $11 million Phase 2 Project further increased the capacity in 2007 from 1.3 to 2.0 mgd with nitrification & denitrification capability. The $14 million Phase 3 project is scheduled to be complete in October 2015, will increase the plant capacity to 2.75 mgd and improve process reliability.  These projects replaced the pond treatment systems. The upgraded plant processes consists of influent pump station, headworks, oxidation ditch activated sludge, centrifuge dewatering, and percolation ponds. 

Water Reclamation Plant No. 4 Expansion

Coachella Valley Water District

Coachella, CA


LEE & RO provided planning, preliminary and final design, and construction management and resident engineering services for a $21 million expansion project, which increased the secondary treatment plant capacity from 6.9 to 9.9 mgd by adding a new 3 mgd nitrogen removing activated sludge plant.  Project components included two aeration basins, two circular secondary clarifiers, a blower building with Turblex blowers, an emergency generator, a gravity belt thickener, a sludge dewatering belt press, chlorine contact tanks, and chlorine and sulfur dioxide storage & feeding systems. 

Anaerobic Digester Rehabilitation Projects

Wastewater Treatment Plant Nos. 1 and 2

Orange County Sanitation District

Fountain Valley, CA


LEE & RO prepared a preliminary design report, plans and specifications, and provided engineering services during construction for an $11 million digester improvements project for the 200 mgd Treatment Plant No. 2.  Plant No. 2 has 20 digesters and this project rehabilitated 7 digesters and 4 digester control buildings.  Project elements included electrical & control system upgrading and automation, addition of sludge flow meters and control valves, sludge and digester gas piping, and structural rehabilitation.  For 150 mgd capacity Plant 1, provided engineering, design, and construction phase services for electrical & control systems portions of a $45 million digester improvement project. The Plant 1 project rehabilitated all 12 digesters to process additional solids from the newly constructed full secondary treatment facilities.

Copper Cove Wastewater Treatment Plant Phase I Expansion
Calaveras County Water District

San Andreas, CA


LEE & RO provided engineering and construction support services for expansion of the existing 0.25 mgd plant to a 0.50 mgd with an ultimate 1 mgd capacity with a peaking factor of 4.  The $1.6 million expansion project consisted of replacement of existing surface aerators in treatment pond 1, pond 2, and finishing pond 3 with 11 new 15 HP aerators.  New headworks, including influent pump station with three grinder pumps, bypass metering structure, and screening facility were also installed.  Other new facilities constructed included pond inlet & outlet structures, effluent pipeline, metering structure, chlorination structure, an electrical building, and an emergency generator.  All facilities improvements were designed for the ultimate plant capacity of 1.0 mgd utilizing Biolac secondary treatment.

Sludge Dewatering Facility

Wastewater Treatment Plant

City of Patterson

Patterson, CA


LEE & RO provided engineering, design, and construction phase engineering services for a $ 2 million biosolids dewatering facility after receiving a Notice of Violation from the Regional Water Quality Control Board over sludge management practices related to use of the drying beds.  The final design incorporated a skid mounted 21-inch centrifuge package having a secondary sludge processing capacity of 225 gpm, including sludge feed pump, polymer unit, grinder and conveyors. The skid mounted packaged allowed for rapid installation. 


Wastewater Treatment Plant Upgrading Project

City of Holtville

Holtville, CA

LEE & RO provided process analysis, project report, final design and construction phase engineering services for $11.8 million plant upgrades to the existing 0.85 mgd treatment plant.  Most of the existing facilities, except continuous upflow DynaSand filters and UV disinfection system, will be replaced. The new facilities added are headworks with a septage receiving facility, grit removal, a Biolac activated sludge with integral secondary clarifiers and aeration blowers, mechanical sludge dewatering and drying beds, a new operations/laboratory building, and a new MCC building.  The upgraded plant will be capable of removing the ammonia nitrogen concentration below the NPDES required concentration of 1.9 mg/l.  This project is financed by the Clean Water State Revolving Fund, North American Development Bank, and Border Environmental Coordination Commission.  LEE & RO assisted the City with successfully obtaining funds from these agencies.

Odor Control Scrubber Modifications

Wastewater Treatment Plants No. 1 and No. 2

Orange County Sanitation District (OCSD)

Fountain Valley, CA


OCSD operated 13 chemical odor control scrubbers at Plant No. 1 in Fountain Valley and 14 scrubbers at Plant No. 2 in Huntington Beach.  This project was to optimize the scrubber performance (e.g. maximum odor removal with least chemical consumption).  Prepared a design report, and provided engineering, design, and construction support services for modifications to 27 chemical scrubbers.  This $3.5 million project reconfigured pH meters and caustic metering pumps, installed Vapex H2S analyzers & controls and ATI wet chlorine gas analyzers and controls, modified flowmeters and controls, and modified chemical piping and pumping configuration. 

Avenue 54 Wastewater Treatment Plant Expansion and Rehabilitation Project, Phase 2

City of Coachella

Coachella, CA


LEE & RO provided engineering, design and construction management/resident engineering services for a $5.5 million project to increase the plant capacity from 3 to 4.5 mgd and to rehabilitate outdated equipment.  The project included rehabilitation of contact stabilization process tanks, replacement of aeration blowers, and addition of new concrete-lined sludge drying beds and electrical and control system upgrading.  Also prepared a project report and successfully secured the USDA funding for the entire project. 

Regional Wastewater Treatment Plant Aerated Grit Removal Facility & Primary Clarifier Improvements

Sacramento Regional County Sanitation District

Elk Grove, CA


The Regional Plant treats average flows of 150 mgd and peak flows of 300 mgd.  LEE & RO analyzed influent hydraulics, methods to improve aerated grit removal efficiency, and rehabilitation of grit transport piping, grit dewatering and truck loading facilities, and odor control systems.  Constructed a pilot aerated grit removal tank model and tested hydraulics and optimized air foil and grit removal efficiency and optimum flow distribution from grit tanks to the primary clarifiers.  Subsequently, LEE & RO provided design and construction phase engineering services for the $7 million aerated grit system improvement projects including modifications of the influent channels for grit removal tanks and primary sedimentation basins, grit transport piping system, grit dewatering and grit truck loading facility.   

Regional Wastewater Treatment Plant Grit Handling & Dewatering System Rehabilitation

Sacramento Regional County Sanitation District

Elk Grove, CA


LEE & RO provided engineering, design, construction support services for $3 million rehabilitation of the grit handling system including the grit piping, cyclones, classifiers, diversion gates, and grit ejectors.  The project replaced old malfunctioning grit ejectors.  The grit piping from the ejectors to the classifiers was replaced with shorter length spools and long-radius elbows to reduce and ease maintenance.  The grit piping from the primary gallery to the cyclone-washer room was replaced with wear-resistant industrial ABS piping.  Additional flushing connections were provided they have greatly reduced plugging.  The four classifiers and eight cyclones were replaced and diverter gates between the classifiers and the screw augers were also replaced.  New grit cyclone overflow piping from the classifier room to the newly constructed rotary screens was added to centralize grit and screenings dewatering.

Wastewater Treatment Plant Phase I & II Improvements
City of Angels

Los Angeles, CA


LEE & RO provided process analysis, engineering and construction management services for $4.5 million Phase I and $6.7 million Phase II Expansion and Upgrading projects.  Phase I included a new headworks with screenings and grit removal, flow equalization, sequencing batch reactors (SBRs), secondary clarifiers, Title 22 filtration, chlorine contact tank, intermediate and effluent pumping stations, aerobic digestion, and sludge drying beds.  The 3 million gal. emergency storage basin was expanded and double-lined with HDPE and leak detection instruments.  A Title 22 UV disinfection system for a winter stream discharge was also included.  Phase II Expansion increased the plant capacity to 0.75 mgd.

Trancas Water Pollution Control Plant (TWPCP)
Los Angeles County Department of Public Works

Alhambra, CA


The 0.3 mgd capacity TWPCP, built in 1963, consists of the headworks, influent pump station, primary clarifiers, rotating biological contactor, aerobic digester, sand filters, and effluent leachfields. LEE & RO prepared an engineering report, prepared final design, provided engineering services during construction, and assisted the County in securing the Clean Water State Revolving Fund.  The $3.9 million upgrades included the influent pump station, equalization, extended air activated sludge with anoxic selectors, dual media filters, and chlorination. LEE & RO also designed monitoring wells and provided the ground water quality monitoring services.

Headworks Rehabilitation Projects

Hill Canyon Wastewater Treatment Plant

City of Thousand Oaks

Thousand Oaks, CA


LEE & RO provided analysis, design, and construction phase services for a $4.5 million project consisted of modification of the North Headworks and rehabilitation of the South Headworks at the 14.5 mgd plant.  The North Headworks modification included replacement of augers with mechanically-cleaned bar screens and installation of new grit pump systems, addition of walkways and grit tank covers, and upgrading of the electrical systems.  The South Headworks rehabilitation included replacement of Infilco Degremont climber screens with Huber step screens and screenings conveyors and compactors, and upgrading of the electrical systems.  The project also included the replacement of piston-type primary sludge pumps with progressive cavity pumps.

Regional Wastewater Treatment Plant No. 2 (RP-2) Improvements

Inland Empire Utilities Agency

Chino, CA

Provided process analysis, engineering, final design, and construction phase engineering services for a $6 million improvements for RP 2, Agency’s regional solids processing plant.  The project included solids processing train upgrades such as installation of the dewatering centrifuge, retrofit of the cake conveyor system, rehabilitation of gravity and dissolved air flotation sludge thickeners, optimization of the centrate pumping system, and addition of a new septage receiving station.  Under this project relocated two dewatering centrifuges, pumps, controls, and conveyors from RP-4 to RP 2 dewatering building.  The RP 2 dewatering system also a centrate handling system.


Rehabilitation of Primary Sedimentation Basins & Replacement of Sludge and Scum Collectors

Point Loma Wastewater Treatment Plant (PLWTP)

City of San Diego

San Diego, CA


LEE & RO was the design engineer of record responsible for engineering, design and construction support services for a $7 million D-B project to rehabilitate 12 primary sedimentation basins at the 240 mgd PLWTP.  The 12 basins were constructed under five separate contracts from 1962 through 1996.  As a result, there are substantial differences in the sludge/scum collectors, such as differences in shaft diameters, drive motors, sprockets, and installation layout. This project replaces a total of 36 longitudinal and 12 cross collectors with new standardized units.  The project also includes detailed inspection of each drained basin, repair of damaged concrete and/or coatings and linings, modification of scum spray actuators, and installation of a new 8-inch diameter water main connected to the plant’s industrial water system.