Some Plant Operators Are Specialists. Team Members at Crystal Lake Do It All.

Operators in Crystal Lake get a complete perspective on treatment plant and lift station operations and regularly rotate duties between them.

Some Plant Operators Are Specialists. Team Members at Crystal Lake Do It All.

Communications and team spirit are vital to effective operations at the Crystal Lake plant, which uses a rotating assignment system built on extensive cross-training.

There’s cross-training. And on-the-job training. And hands-on training.

And then there’s around-the-horn training. That’s what they practice at the Crystal Lake (Illinois) Wastewater Treatment Division. “We’re responsible for two wastewater treatment plants and 30 lift stations,” says Dan Langguth, division superintendent. 

“When the lift stations were assigned to us in 2014, it made sense and we decided to divide our staff into three teams and rotate them every four months between the plants and the lift stations. Three staff members were promoted to facility operators to fulfill leadership roles at their assigned facilities.” The leaders of the three facilities rotate every six months.

That way, everyone gets trained and gains experience on all aspects of the division’s operations. “It gives us a fresh set of eyes every quarter,” Langguth says.

Tertiary process

Crystal Lake is a pleasant community of 44,000, just an hour northwest of downtown Chicago by commuter train. Both wastewater treatment plants underwent recent upgrades to improve hydraulic capacity and solids handling, following a master plan developed by the engineering firm HR Green.

Plant 2 is the larger of the two, with a design flow of 5.8 mgd and an average flow of 4.3 mgd. Two influent wet well stations feed new wastewater into the headworks, which houses a pair of rotating fine screens (Lakeside Equipment), a backup manually cleaned bar screen, and an aerated grit chamber.

A pair of ultrasonic flowmeters (Fuji Electric Corp. of America Model Delta-C) is installed on the influent pipes. Alum is added at that point to remove phosphorus and barium, which occurs naturally in the groundwater. The alum is added after the primary clarifiers and again in the secondary clarifier drainpipe, which flows back to the head of the plant.

After primary settling, the wastewater flows to 13 aeration basins, operating in series and equipped with fine-bubble diffusers (SSI Aeration). APG-Neuros turbo blowers generate the air. 

The flow settles in a series of five circular clarifiers, all with Spiral covers (Walker Process Equipment, A Div. of McNish Corp.). Four Infilco-Degremont low-head automatic backwash sand filters (SUEZ) polish the effluent before it is disinfected in a TrojanUV4000 UV system. From November through April, the plant is exempt from the disinfection requirement.

Sophisticated control

The receiving streams are the Crystal Creek and Sleepy Hollow Creek, tributaries to the Fox River. Concern from environmental groups about the effluent temperature prompted the city to construct a cooling pond so the water can reach the ambient temperatures before release.

The plant employs a state-of-the-art Allen-Bradley SCADA system (Rockwell Automation) that enables operators to remotely monitor operations. The plant also has a dual power feed and a 1.5 MW standby generator (Caterpillar) that can run the entire plant in the case of a power failure.

The on-site laboratory, managed by Emma Kohl, has won numerous awards for accuracy and efficiency. It includes a flame atomic absorption unit for metals detection. Lab technicians from other locations often come to learn procedures.

Plant 2 also maintains the only U.S. EPA-approved pretreatment program in the county. Ken Krueger, pretreatment coordinator, monitors the city’s industrial discharges and leads an ongoing program of inspection for fats, oils and grease.

The team also includes Sam Ferraro, wastewater supervisor; Adam Behrns, Brian Campion and Russ Hornung, facility operators; and Jeff Lundy, Mike Wisinski, Kelsey Snell, Bill Martenson and Dan Oates, maintenance personnel.

Solids handling

The new solids handling additions have given the plant redundancy, Ferraro says, wastewater supervisor. “Previously, we had a single anaerobic digester, one centrifuge (Centrisys/CNP) and a gravity belt thickener,” he says. If the equipment was out of service, the plant was overloaded with solids, and staff often had to be creative to manage the solids inventory: “We would store them in the aeration basins.”

The new $5.8 million configuration includes a second anaerobic digester and a new centrifuge (Alfa Laval). The Centrisys/CNP unit was rebuilt with new bearings, bowls and scrolls. Both digesters have floating covers (Walker Process Equipment, A Div. of McNish Corp.).

A key addition was a climate-controlled solids-handling building. Standing in what’s left of the old dewatering structure, Langguth and Ferraro can point out deterioration in the walls caused by hydrogen sulfide and moisture. “We took a problem and turned it into an upgrade,” Langguth says.

Crystal Lake can run the digesters in the parallel or series mode. “We primarily run the digesters in series,” Ferraro says. “We send primary sludge and waste thickened sludge to Digester 1. We heat and mix this digester and most of the volatile solids destruction happens there. Then we transfer the sludge to Digester 2, which we don’t heat or mix. The material is allowed time to settle and we decant water off the top. The secondary digester has very little biological activity, but we get the benefit of thickening there.”

Boosting solids content

Typical solids content in the first digester is 1.7 percent; it increases to 3 percent solids in the second digester. “We benefit by not having to run the centrifuge as often as we would have to if we went with lower total solids,” Ferraro says. “We’ve also seen a decrease in polymer usage in the centrifuge.”

The second centrifuge gives operators extra thickening capability is case the gravity belt thickener should be out of service. Dahm Enterprises hauls cake at 22 to 26 percent solids and spreads it on farm fields.

A second facility

At the time of the facility master plan, the city considered bringing all wastewater flows to Plant 2, “But the cost numbers were stifling,” Langguth says. So Plant 3, in the growing northwest area of the city, was kept in the plan and upgraded as well.

The flow (1.7 mgd design, 0.54 mgd average) passes through a mechanical bar screen and compactor (Headworks International) at the main pumping station about a quarter-mile away from the plant. Biological treatment is accomplished in two packed-bed reactor towers, each 29 feet high and 60 feet in diameter. The towers are operated in series, and a portion of the flow is constantly recirculated to be sure the filter media stays wet. New media replaced the old media in the towers.  

After the towers, alum and polymer are added to the flow, which then settles in two Spiral-covered secondary clarifiers. Settled sludge is pumped to aerobic digesters, powered by three new rotary screw blowers (Aerzen). A pair of Infilco-Degremont traveling bridge sand filters (SUEZ) follow, operating in parallel. Disinfection is provided by 15 percent peracetic acid.

“We used to feed sodium hypochlorite for disinfection, but it was causing permit violation issues for dichlorobromomethane,” Ferraro says. “Once we switched to peracetic acid, we haven’t had an issue. The plant achieves maximum bacteria kill, and there is no trace of the acid in the effluent.”

Like Plant 2, Plant 3 has an automated alarm system that contacts on-call operators via cellphone and tablet. A SCADA and advanced data system informs operators of problems with equipment or plant operations and monitors maintenance requirements.

Rotating duties

With the three staff teams rotating through the plants and lift stations, communications are vital and esprit de corps can make or break the day. Langguth has absolute confidence in the rotating assignment system and the operators’ ability to function as a team. “Everybody rotates, including maintenance,” he says. “Not only do we get a new look at things, the rotation aids in knowledge transfer and can lead to different or more efficient ways to operate.

“We meet every morning as a whole group for 20 to 30 minutes. We go over operations and spend a few minutes on a particular safety topic — confined space, weather conditions, safe driving or first aid.”

Quarterly, the group reviews a special set of emergency guidelines, outlining procedures to be followed in case of events like multiple lift station power outages, contact and communication with the general public, or high flows at the treatment plants.

Langguth believes strongly in learning by doing: “Our guys are the boots on the ground and the reason for our success. We let them learn hands-on, not just identify problems, but what to do, what to try, what’s the best solution. If it’s not related to safety or a permit violation, it’s OK if they make mistakes. We trust people. That’s how we roll.”


Good chemistry

It might seem odd that wastewater odor specialists would travel around the globe to smell nothing. But that’s the situation at Plant 2 in Crystal Lake, Illinois, where a new odor-control system is eliminating foul smells at key points around the facility. With neighbors right across the fence line, that’s important.

The plant upgrades included an innovative dry fog system (OMI Industries) using a proprietary chemical compound, Ecosorb. The chemical mixes with air and is distributed around the plant through a network of 6-inch PVC piping. Critical areas include the headworks, primary tanks and solids handling building. The fog is released through small ports in the pipes. Through a chemical reaction, it neutralizes odorous compounds in the air.

If you place your hand over one of the holes, you can feel the gentle flow of air, but you smell nothing. Dan Langguth, Wastewater Division superintendent, says wastewater specialists from a number of countries have visited in the last couple of years to check out the system.



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