This article first appeared in the March 2018 issue of Treatment Plant Operator magazine, published by COLE Publishing, Three Lakes, Wisconsin. It is reprinted by permission.
Cross-training staff in all facets of treatment plant operations, maintenance and laboratory analysis is yielding big dividends at the Carpinteria (California) Sanitary District.
One reward was the 2016 Small Plant of the Year award from the California Water Environment Association, the second time Carpinteria has received that honor for plants treating less than 5 mgd. The district also won the 2016 Small Collection System of the Year award, becoming the first agency of any size to win both in the same year.
“Cross-training has enhanced our ability to manage and improve our treatment processes,” says Mark Bennett, plant superintendent. “There is no division of duties within the operations department. Our small plant and team atmosphere keep everyone in the loop, whether we’re working on projects or day-to-day operation and inspection of the plant and lift stations.”
The district strives to maintain a staff where everyone brings a different strength or talent to the table. “Leveraging these strengths, along with the district’s training regime, has been invaluable in normal operating conditions, in times of crisis, and in our discussions to improve our processes and performance,” Bennett says.
The Carpinteria district was established in 1928 and owns and operates 46 miles of wastewater pipelines serving a population of 15,000. The district’s 5-square-mile service area lies 12 miles southeast of Santa Barbara and contains a mix of residential, commercial, light industrial and agricultural land uses.
The wastewater treatment plant lies near the Pacific Ocean beach, close to the center of town. The original plant was built in the 1950s. After substantial upgrades in the 1960s and a total rebuild in the 1990s, it is designed for 2.5 mgd; average flow is 1.1 mgd.
Pumps deliver influent to the headworks with a self-cleaning mechanical bar screen (Parkson Corp.) and a J+A Jeta grit cyclone grit separator (Ovivo USA). The flow then enters a primary clarifier, covered to limit odors. Primary effluent is blended with return activated sludge as it enters two activated sludge basins, operated in series in the extended air mode.
Air is injected into the two basins (four zones) with new high-speed turbo blowers (APG-Neuros) and fine-bubble diffusers (Sanitaire – a Xylem Brand). Each zone has a dissolved oxygen probe, airflow meter, and motorized flow control valve. The speed and airflow for each blower are determined by a DO setpoint.
Effluent is disinfected with sodium hypochlorite and dechlorinated with sodium bisulfate before discharge to the ocean through an ocean outfall with diffusers. An in-house dive team conducts a video survey to assess the outfall’s condition once a year. Biosolids are aerobically digested, then dewatered on a belt press from Envirex (Evoqua Water Technologies) to 18-19 percent solids.
The plant also uses a screw press (Huber Technology) for dewatering. Cake is conveyed to 10-ton roll-off bins, which are hauled by a private contractor to an Engel and Gray fully permitted composting site near Santa Maria, 65 miles away. There, the material is mixed with green waste and feedstock from local wineries and marketed locally as a soil amendment.
Bennett started at Carpinteria as an operator-in-training in 1988 and worked up through the ranks, earning his Grade 5 certification and becoming operations manager. With 29 years’ experience, he also holds California Water Environment Association Grade 4 plant and collection system maintenance certification. His experience follows the cross-training matrix used at Carpinteria.
Mark Rogers, treatment supervisor, has 24 years at the district and is a Grade 3 operator; he also has certifications as a mechanical technologist, laboratory analyst, and collections system maintenance technologist. Keith Sweningson, Grade 3 operator, has 15 years’ experience and holds the same additional certifications as Rogers.
Frank Gonzalez, laboratory director and a Grade 3 operator with 32 years’ experience, manages the plant’s quality assurance/quality control program and handles lab training. Branson Taylor (12 years) is a Grade 2 operator certified in collections and mechanical; and Kenneth Balch (6 years) is a Grade 2 operator certified in collections and plant maintenance. Julio Martinez is an operator-in-training.
Bennett feels strongly about having operators who can work in the laboratory, besides being able to troubleshoot SCADA systems, repair pumps and perform general maintenance. “By running the lab, operators gain a unique perspective that comes from collecting the sample, performing the analysis, and adjusting treatment processes as needed,” he says.
Out with the old
As Bennett and his team take on many plant improvement projects themselves, Carpinteria saves money on outside labor. Recently, the district replaced two anaerobic digester tanks that dated to the original plant with new aerobic digesters. New feed pumps move the biosolids to the dewatering system.
“We contracted with Carollo Engineers to do a solids handling master plan for us,” Bennett says. “The plan included the possibility of upgrading the old digesters to meet new seismic standards for California and adding redundancy to our system, but the cost was virtually the same as constructing the new aerobic digesters. During the transition, operators converted one of the existing aeration basins to aerobic sludge digestion, and we operated for about a year with one activated sludge basin online.”
The staff cleaned the old anaerobic digesters before their demolition, saving the district thousands of dollars. The district also installed a new storage and chlorination-dechlorination facility using equipment from Evoqua Water Technologies and UGSI Chemical Feed a UGSI Solutions. During that transition, the operators ran a temporary disinfection system using salvaged equipment.
“Without the buy-in and hands-on approach to completing these projects, we feel the district is at the mercy of a vendor or contractor,” Bennett says. “That’s certainly not a good place to be when a critical piece of equipment fails.”
On the controls side, the Carpinteria staff planned and completed replacement of two PLCs and concurrently installed two local HMI screens. “First, we did the one that controls the influent lift station,” Bennett says. “That was completed early in 2016. Later that year, we did the one that controls the return activated sludge and primary and secondary wasting.”
The PLCs replaced obsolete electrical equipment installed in the early 1990s. “The new controllers are networked to our SCADA system, allowing process monitoring and reliability,” Bennett says. “The project was designed by our operators, with programming assistance from the district’s contract SCADA integrator, Nader Vakilian from AIA Automation. Each PLC was installed and tested in-house.” The total cost was $59,000, far less than if the work had been contracted.
Carpinteria also made significant improvements to the plant’s communication backbone as part of the $7 million digester capital improvement program. These included major SCADA enhancements, a new fiber optic system, and the installation of telemetry throughout the plant.
The staff was also instrumental in digitizing the plant’s existing and new operations and maintenance manuals.
“Our staff scanned the majority of the manuals and downloaded the others from manufacturer’s websites,” Bennett says. “In the process, we updated all our manuals to reflect current information.” The digital manuals reside on the district’s server but have also been uploaded to the cloud to allow secure internet access. Operators can download the manuals on their tablets and have access to them in the field.
Up with efficiency
Operators have also worked with design consultant and district management to reduce the plant’s energy usage. “Our new Huber screw press uses less energy than the previous dewatering equipment, and it returns less centrate to the plant for additional treatment,” Bennett says. “Likewise, new return activated sludge pumps are better sized to current plant flows.”
The plant also took part in district-wide replacement and retrofitting of lightning with low-energy LED lamps. The new 75 hp high-speed turbo blowers with variable-frequency drives replaced oversized 150 hp multistage centrifugal blowers that dated back 25 years. Bennett estimates savings near 33 percent from the blower-diffuser project alone: “Plus, we have substantially reduced our carbon footprint and improved our odor control.”
In Carpinteria’s Plant of the Year award submittal, Bennett writes, “The district takes great pride in operational efficiency. Each year, we strive to achieve highest level of facility maintenance and improvement at lowest possible cost to ratepayers. The result is a lean and efficient staff coupled with smart and calculated resource allocation.”
It pays off: Investments in improved operations have essentially allowed spending to remain level from year to year. Bennett observes, “Current year spending is actually 0.08 percent less than last year.”
Operator ingenuity at Carpinteria Sanitary District has enabled a giant leap forward in data management. Superintendent Mark Bennett calls the program “Paper Lite,” and it figured prominently in the Small Plant of the Year award that Carpinteria received in 2016.
“The project was initiated and implemented entirely by our plant operations staff,” Bennett says. What began as a pilot test using two refurbished Apple iPad Mini tablets turned into a plant-wide system of data management and retrieval that has streamlined the inspection process across the board.
“It started with the creation of an Excel worksheet that mimicked the paper forms used for daily plant and lift station inspections,” Bennett says. “The familiar layout made it easy for operators who were less tech savvy to learn the format.”
At first, the inspection findings were captured each day on the iPads and then emailed to the supervisor. It has become much more sophisticated. Using the same layout, the inspection sheet uses circular referencing, meaning staff can time-stamp the inspection of each piece of equipment or process. Also, the form now has fields for notes and comments that allow for voice data entry, digital photos and other features to accurately reflect conditions in the field. A drop-down menu speeds up data entry.
There was a learning curve, although younger operators readily accepted the new format. “The greatest benefit is that inspection forms for each day are stored in a flat PDF file format that is searchable,” Bennett says. “This allows staff to find information quickly, using a wide variety of search parameters.”
Savings from paper costs alone have already paid for the iPad tablets. “We now have an iPad assigned to each operator,” Bennett says. “When we move our asset management system to the platform, we will be totally paperless.”