The 1.5-mgd tertiary-treatment wastewater reclamation facility h…
We began with a twin focus: plan the startup a new 1.5-mgd biological nutrient removal wastewater reclamation facility and guide rehabilitation of the existing water production and distribution system.
But almost immediately, we added a third: the city’s 32 wastewater lift stations, some of which had suffered serious physical, mechanical, and electrical deterioration over a 30-year life span. Minor electrical failures and clogged pumps were leading to frequent alarms. We decided to thoroughly inspect and clean all 32, and discovered in the process that some would need to be entirely replaced. Approximately half were cleaned within a week for $5,000. Alarms immediately decreased by 25% and, after one year, by 80%.
The first 12 months of a new contract are the most difficult because they require both operational (i.e., technical in terms of equipment and processes) and organizational (i.e., psychological as city employees wrestle with deciding which employer to work for and implement the decision) change. Employees appreciated the fact that progress came in steady steps. In fact, as improvements began manifesting themselves team members spent both work hours and time off to clean and refurbish building exteriors and interiors, pumps, piping, floors, and grounds.
In addition to the aesthetics effort, we identified and tackled a list of other tasks: rewriting standard operating procedures, undertaking a thermography scan to find electrical hot spots, developing a repair schedule and preventive maintenance plan, and upgrading the master lift station’s electronic controls.
Meanwhile, other team members focused on the intricacies of starting up the treatment operation.
The existing digester and sludge thickening tank were reconditioned without taking the plant off line. The two existing effluent storage ponds were cleaned and disinfected. The rotating biological contactor (RBC) unit was demolished and removed during construction of the new system and plant employees learned how to operate the new Fournier Industries Inc. sludge dewatering system.
We maintained effluent compliance during construction by working closely with the site engineer and contractors. The final element was to the live tie-in of the influent flow from the old plant to the new. We had three concrete saws on hand when it was time to cut the old line and connect it to the new. This prevented a major spill or lift station overflow when the first two saws failed, and the job was completed within two hours without a break in service.
Planning ahead also paid off vis-à-vis employee proficiency with new equipment once it came on line.
We convened detailed and open daily and/or weekly meetings throughout the 120-day period preceding startup.
An early start is particularly helpful in resolving vendor/operator availability conflicts. We scheduled 1- to 4-hour training sessions at least three to four days of each week in the two months before formal startup. This ensured the information remained fresh and gave employees an ongoing opportunity to ask questions about anything that wasn’t clear during their previous instruction.
“The learning curve can be steep for individuals without broad wastewater experience,” says Wastewater Reclamation Facility Manager John Sowka, a Woodard & Curran facility manager. “We made the most of frequent training sessions and the presence of the vendor’s field staff. You can’t ask too many questions.”
Meeting disinfection byproduct regulations
Construction was almost finished when the city learned it was being placed under a consent order for exceeding maximum contaminant levels for trihalomethanes (THM) and HAA5s (the haloacetic acid family) in the drinking water.
Initial engineering evaluations identified capital-intensive filtration options including enhanced coagulation/ filtration, activated carbon, and reverse osmosis. A city of 10,000 isn’t in a position to quickly restructure rates and obtain the necessary bonding to fund such systems, all of which exceeded $2 million.
That narrowed the options to a chemical solution.
Ozonation was eliminated in part because of capital requirements, but also because we weren’t convinced it would succeed as a sole solution to the problem.
Chloramination accomplishes disinfection through the addition of ammonia and is thought to adversely affect the taste and odor of treated water. However, studies and feedback from utilities that already had these issues — as did Inverness, where water supplies have very high levels of iron and manganese — indicate that chloramination can actually improve water quality aesthetics.
While less costly in terms of construction, operating a chloramination system requires additional operations expertise. Inverness had an existing relationship with one of Florida’s largest chlorine suppliers, Odyssey Manufacturing Co. in Tampa, which has extensive experience with the process. President Pat Allman described several case studies in detail and outlined the fundamental needs, activities, goals, and expectations to give us the confidence we needed to move forward.
That effort kicked off with cleaning and rehabilitating the existing 500,000-gallon storage tank using existing earmarked capital improvement funds and installing a 2,200-gpm aerator. The tank’s exterior was painted to match the water plant and branded with the city’s logo. The rehab was completed over a 12-day period for $125,000.
Converting to chloramination involved adding a Foxcroft FX1000-Pon-line total chlorine residual meter, an ammonia skid with two feed pumps, a day tank with a digital scale, and a new feed line to the storage tank. Additional activities included:
“Chloramination can create its own set of problems if dead end lines aren’t eliminated or flushed regularly,” says Woodard & Curran’s overall utilities Project Manager Brian Heath. “You need to think through a lot of permutations involving flows, water chemistry, equipment dosage controls, and how you can best use staff to effectively flush and monitor the system each day for the first two weeks of operation. You have to plan on committing a lot of attention to the front end of this kind of process.”
As we enter our fourth year with this client, the experience has been one of the most rewarding in my 35-year career. Former city employees who’d been indifferent to pursuing certification seem renewed by the prospect of expanding their career path. Our management team is directly involved in planning and implementing capital improvements. The relationship proves public and private workforces can effectively collaborate to tackle and resolve multiple problems at once, understanding what can go wrong and preparing for those contingencies.
Public Works Director Katie Cottrell recently told me, “The team worked so well together and the added technical support was essential to all that we were able to accomplish.”
—Cherniak (mcherniak@woodardcurran.com) is a senior vice president with Woodard & Curran and serves as senior area manager for facilities the firm contract-operates in Florida.
WEB EXTRA
To read how one town explained the switch from chlorination to chloramination to disinfect drinking water, click here.
