An Environmental Management System helps the clean-water agency in Louisville, Ky., improve every facet of the processes for making its signature biosolids product
When Louisville & Jefferson County Metropolitan Sewer District received the National Biosolids Partnership (NBP) seal last summer, it was as if the staff of the Morris Forman Water Quality Treatment Center itself had received a badge of honor.
“It meant a lot,” says Sharon Worley, senior technical services engineer. NBP certification validated the biosolids process and Environmental Management System (EMS) to district management and the public, while acknowledging and rewarding a major staff effort.
Louisville received NBP certification on July 31, after two-and-a-half years of meticulous work on its EMS, and successful completion of a detailed third-party audit. The certification signifies that the biosolids production process is dependable and safe for its customers and the environment, and that the 82 tons per day of Class A Louisville Green pellets, which are spread on farm fields in 11 states, unquestionably deserve their EQ (exceptional quality) status.
“The most valuable lesson learned throughout the implementation of our EMS is that if you can effectively measure something, be it quality or performance, you can then begin to study it and eventually control it,” says David Coe, Louisville EMS coordinator. “We’ve seen it happen in numerous situations, and it will continue to happen throughout our biosolids value chain as our EMS continues to develop.”
Coe says the biosolids program is now more focused, with goals and objectives for maintenance, pretreatment, operations, marketing and public participation. “Our focus was always to produce exceptional quality biosolids and encourage beneficial reuse,” he says. “However, establishing clear goals and objectives has encouraged several improvements in the quality of Louisville Green, as well as stronger efforts in public participation.” He reports that demand for Louisville Green exceeds the supply.
The path to pellets
The Morris Forman facility can treat a dry-weather flow of 120 mgd and 350 mgd during wet weather. It is the largest of six treatment facilities serving Louisville and Jefferson County — indeed, the largest treatment plant in Kentucky — and serves as the biosolids processing center for the entire metropolitan district. Solids from the outlying plants are either trucked or pumped to Morris Forman.
Solids from the Morris Forman plant’s primary process are anaerobically digested. The plant’s waste activated solids and the imported solids are thickened in Komline-Sanderson dissolved air flotation units. All the solids streams — about 720,000 gallons per day — are blended to a solids content of about 3 percent. The material passes to dewatering wet wells and then to a bank of five Alfa Laval DS 706 centrifuges.
The machines, each designed to process 2.5 to 3.0 dry tons of solids per hour, spin the material into a 22 percent solids cake before the drying and pelletization step. Four Andritz natural-gas-fired rotary drum units make up the drying system. Each dryer train can evaporate up to 1,900 pounds of water an hour.
Pellets are then cooled, segregated and placed into final-product silos for loading into trucks. “We believe this is the largest-capacity rotary drum direct drying system in North America,” observes Morris Forman biosolids processing manager Robert Bates.
The pellets have a minimum dry solids content of 94 percent and range from 1.5 to 2.5 mm in size. The nutrient value is 5-3-0 (NPK), but the pellets contain other nutrients, minerals and organic matter that commercial fertilizers lack. They qualify as Class A, exceptional quality biosolids by EPA standards.
Louisville performs regular testing of the pellets every 90 minutes, assuring proper pellet size and density. Every truckload is tested, as well, before the truck shoves off for rural areas. “If the pellets are too large, they won’t break down quickly enough,” says Bates. “If they’re too small, they won’t broadcast properly out of the spreader.”
Bates’ crew uses an oil mixture to control dust during transportation and application. Regenerative thermal oxidizers are used to control odors from the dryer trains. Under an agreement with a private marketing contractor, AJ Inc., Louisville sells nearly all of the material to farmers. Home use accounts for less than 1 percent. Area golf courses and metropolitan parks consume another small portion.
The Morris Forman plant captures methane produced by the digestion process and uses it to fuel the drying furnaces, saving some $3,000 per day. “About 80 percent of the heat requirements of one dryer train can be met with our digester gas,” says Bates. While revenue from biosolids amounts to more than $120,000 per year, the money is not in the sale of pellets but in the savings from “landfill avoidance.” Bates says that number exceeds $500,000 a year.
By definition, an Environmental Management System is a validated process of organizing, monitoring and controlling a biosolids process from pretreatment through to final disposition of the end product. In reality, it amounts to hard work and dedication, starting with unwavering support from top management.
Says Worley, “Our director, Bud Schardein, was the driving force toward certification of our biosolids process. He had the vision.” Coe explains that when the Morris Forman plant began using dryers to pelletize biosolids, staff personnel had a lot to learn.
“The end-product quality was not as good as it is today because we didn’t fully understand the needs of end-users, and we had little experience with the technology,” Coe says. Tighter specifications and better quality-control equipment markedly improved the situation.
“We developed a product that exceeded the EPA standard for exceptional quality and controlled pellet size through the use of a sieve capture test,” Coe observes. “That helped us produce a product that was much more desirable to the end-users.”
Louisville signed a letter of commitment with the NBP in 2004 and began aggressively pursuing EMS certification in April 2006. “We struggled with it at first,” says Worley. But what at first appeared to be a paperwork nightmare has become a much more practical, smooth-operating process, as NBP has made improvements to the certification procedures.
Right away, Louisville management saw the need to have a single person in charge of the EMS process. Coe, who had more than 20 years of experience in wastewater plant design and operation, was hired to lead the EMS effort. First item of business: set up the team.
“For years Louisville had used a management team to guide the production of the biosolids, but the team was not necessarily focused on all of the EMS principles,” Coe says. “Once I was hired, we established an EMS core team to follow the biosolids value chain. It consisted of the operations manager, the wastewater process managers, the maintenance manager, a senior engineer, a technical specialist, in addition to the EMS coordinator.”
Later, Coe explains, the pretreatment manager, laboratory manager and operations supervisor were added to the team as essential members. The team began meeting regularly to discuss progress toward meeting the NBP requirements and prioritizing efforts in areas where the biosolids process needed strengthening.
The meetings have been a key to success and have been expanded to three levels: a weekly meeting to review goals and objectives, a second meeting every other week to review the plan, and a third to address public participation.
The result, Coe says, is that each team member has become more conscious of the efforts and problems facing the others. “The accountability and effort of the team improved,” he says. That has led to improved product quality and increased public acceptance of it, to the point that over the last two-plus years, almost 100 percent of the material made available for distribution has been beneficially reused; none has been landfilled.
Another important facet in success has been the incorporation of existing practices into the EMS. “That’s been one of the biggest accomplishments — rolling existing training programs and SOPs [standard operating procedures] into our EMS program,” Coe says. He believes the training programs have produced tangible benefits: increased competency and professionalism among plant staff, and an appreciation by upper management that training programs really do make a difference and warrant the investment.
And it’s more than just competency. “Incentive and motivation, working conditions, feedback, performance measurement, clear work standards or standard operating procedures, and an individual’s learning capacity are directly related to individual performance,” Coe says.
There are process benefits, too. “Attention to controlling the biosolids processes has contributed effectively to the liquid side of the Morris Forman plant,” says Coe. “We’ve had no permit violations since October 2006.”
Another development: The EMS process has brought into focus how important the pretreatment program is to biosolids quality. Louisville’s EMS mandates relentless monitoring and measurement of all the steps associated with biosolids processing — a complete inventory of every critical operations point.
This is cross-linked with all internal and external requirements for the operation, particularly legal and regulatory requirements. “EMS forces you to get all these requirements together, and monitor performance against them,” Coe says. The natural follow-on, of course, is implementation of specific corrective actions as needs arise.
Finally, says Coe: “None of the progress could have been made without the professional efforts of our maintenance department. In addition to their typical workload, the maintenance and operations team set as an objective the modification and improvement of the digester gas collection system, so that the gas is now used to fuel the drying system. They also developed the oiling system that controls pellet dust.
“They’ve always done a great job keeping the Morris Forman plant operational even under the most adverse conditions.”
What else did Coe, Worley, Bates and the rest of the team at the Morris Forman plant learn from the EMS process? For one thing, don’t commit to it until you’re ready. For another, once you’ve committed, there’s no backing out.
Still, the team believes the audit was highly beneficial. “Going through the third-party audit was a great experience for us,” says Coe. Senior management became very involved in operations and in developing public acceptance. And we were challenged by the audit.
“We got a much better understanding of the improvement process and how goals and objectives, audits, and a good corrective action plan all provide performance measures and understanding,” Coe says. “These can be demonstrated in a program perfor-mance report that then becomes the link between the biosolids program and director-level management.
“As an organization becomes more conscious of the improvement process, only good things can come from it — a better plant, a better product and better people.”