Managing Water Quality
How We Produce Safe, Good Tasting Water
Ozone (O3) is formed by passing oxygen (O2) through an electrical field and it has several advantages over chlorine in water treatment. Water treated with ozone tastes and smells better, ozone destroys a wider range of organisms, and it produces less disinfection byproducts. After it is used, it turns back into oxygen and is released into the air.
The EPA and California Department of Public Health regulate and enforce water quality standards to assure the safety of California’s drinking water. Enforcement includes inspections, mandatory reporting, and the certification of staff. Helix’s plant has had no primary water quality violations in 50 years of operation.
A chemist and biologist work onsite in fully equipped labs to monitor the quality of water coming into the treatment plant and at each step in the treatment process. Each day, 200 water quality tests are performed at the treatment plant, and more are performed throughout Helix’s water distribution system, in the communities we serve.
Real Time Data 24/7
Helix’s Supervisory Control and Data Acquisition (SCADA) system allows treatment plant operators to monitor and control the treatment process in real time, 24 hours a day, seven days a week. Remote sensors alert operators to potential issues and provide the data needed for diagnosis, decision-making and response.
Maintenance staff utilize a Computerized Maintenance Management System (CMMS) to schedule, perform and track maintenance on more than 1,900 pieces of equipment. This increases the treatment plant’s reliability, reduces breakdowns, increases efficiency and lowers costs.
Our Water Treatment Plant
Helix’s R.M. Levy Water Treatment Plant operates 24/7 to produce drinking water that tastes good and meets all state and federal safety and quality standards.
Million gallons per day (MGD)
Construction began in 1963
Highest Average Day
July 13, 2006
Construction began in 1998
One Archimedes Screw can lift 45 million gallons of water per day.
How We Treat Water
Imported water from the Colorado River and State Water Project goes directly into the plant at up to 73,000 gallons per minute or into Lake Jennings where it is stored until needed.
Mixing Basins (2)
Alum (aluminum sulfate) is mixed with incoming water in a process called coagulation. Alum destabilizes particles in the water and they become chemically attracted to each other. As water moves through the mixing basins, the destabilized particles form larger particles called floc.
Sedimentation Basins (3)
The floc settles on the bottom of the sedimentation basins. Each sedimentation basin is 244 feet long, 14.5 feet deep and holds 2.3 million gallons of water.
Ozone is formed by passing oxygen through an intense electrical field. The oxygen molecules (O2) break apart and reform as ozone (O3), a powerful disinfectant that destroys bacteria and microorganisms in water. Ozone is highly effective at treating taste and odor constituents in water, as well. When disinfection is complete, the ozone is converted back into oxygen and released into the air.
The water is filtered through Anthracite coal and sand to remove any remaining particulate matter.
Chlorine Contactor (6)
A minimal amount of chlorine and ammonia is added to form chloramines, which protect the water against any potential contamination while it is in Helix’s distribution system.
Storage of Finished Water (7)
Finished water—drinking water—is held in a storage tank and then distributed to Helix customers. Helix also distributes drinking water to Lakeside, Padre Dam and Otay water districts.
Our Plant Operators
Helix’s treatment plant operators can manage water treatment and distribution from the Control Room.
Certification as a water treatment plant operater requires coursework, on-the-job experience and successfully passing rigorous examinations at each of the five certification levels. Helix’s treatment plant staff is doing the work, and our customers benefit.
Percentage of staff at each level (Level 5 is highest)
- Grade 5 Certification (T5) 19%
- Grade 4 Certification (T4) 44%
- Grade 3 Certification (T3) 19%
- Grade 2 Certification (T2) 19%
Benefit: Lower Staffing Levels
The median staffing level nationwide for a 106 MGD water treatment plant is 25. Helix manages our plant with a staff of 17 and we have done it through the certification of administrative and support staff, and the in-house development of automated systems.
Benefit: In-House Capabilities
The key to operational efficiency is process management and automation. Helix’s SCADA (supervisory control and data acquisition) system allows operators to acquire information from and control equipment in remote locations throughout the R.M. Levy Water Treatment Plant and Helix’s entire water distribution system. At each remote location, programmable logic controllers (PLCs) connect to sensors monitoring processes and convert the sensor signals into digital data.
Replacing a SCADA system is a large investment for a water utility. In 1986, bids to replace Helix’s SCADA system already exceeded $1 million. Today, the cost is approaching $3 million. Helix avoided these costs when plant operators offered to build a SCADA system in-house.
Helix employees complete the in-house design and installation of a full SCADA system for $400,000. The project also eliminated annual costs of $55,000 for phone lines and $16,000 for VAX computer support.
PLCs are installed on all large pumps. Today, more than 150 PLCs control processes throughout the water treatment and distribution systems.
Employees began replacing the SCADA system with Inductive Automation’s web-based software (Helix was the first water utility in California and the second in the U.S. to take this innovative step). Reusing the radio and PLC network from 1997 reduced the cost of the project to $45,000 and allowed staff to fund the project out of their normal operations budget.
Employees began development of an Ethernet radio system. The project is expected to cost 10-20 percent of what other districts have paid for their systems.