Judge This Book By Its Cover

Steady improvements keep a small secondary plant in Texas compliant with regulations and in peak operating condition despite budget limitations.
Judge This Book By Its Cover
Gretchen Baldwin, Willis Wastewater Treatment Plant manager, with Arthur Faiello, director of public works.

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If you just happened to pop in at the Willis Wastewater Treatment Plant, the team would not object to giving you a tour.

That’s because the plant and the grounds are always in tip-top shape, thanks to the hard work of Gretchen Baldwin, chief operator. The grass is mowed, the equipment clean, the floor spotless, everything painted. In the words of Arthur Faiello, public works and utilities director for this south Texas city of 6,000, “We’re always tour-ready.”

While some plants want to spend as little as possible, that’s not the approach at Willis, Faiello says. He believes that since the city has made an investment in effective wastewater treatment, the facility’s appearance should reflect the money spent on it.

The approach is not only pleasing to the eye — it has paid off in the 2013 Texas Plant of the Year Award from the Water Environment Association of Texas (WEAT) for facilities treating less than 1 mgd.

Plant operations

The current wastewater treatment plant dates to 1977, when it was built to replace a facility that had reached the end of its useful life. The original plant (0.4 mgd design) used an oxidation ditch equipped with brush aerators, secondary clarifier and chlorine contact chamber. Biosolids were spread on drying beds.

Since then, Willis has expanded the plant capacity to 0.8 mgd and has made additions to the chlorine contact chamber, the aeration and mixing process, and the biosolids digestion and dewatering processes. Influent screening has been added.

Today, the plant handles about 0.5 mgd on average. Wastewater is collected through 28 miles of gravity pipes and 17 lift stations. The CleanFlo Spiral screen (WesTech Engineering) in the headworks removes rags and debris, and the wastewater passes to the racetrack-style oxidation ditch, where pontoon-type Tornado aerators (AEROMIX Systems Inc.) supply oxygen and mix the contents.

Treated water passes through two 45-foot-diameter, 18-foot deep clarifiers and is then gas-chlorinated via 150-pound cylinders through a Superior auto-valve (Chemical Injection Technologies) before discharge to the East Fork of the Crystal Creek.

Biosolids are aerobically digested (blowers by Hoffman & Lamson), decant thickened, then dosed with polymer and dewatered on a belt filter press (Alfa Laval Ashbrook Simon-Hartley). A contractor takes cake at 18 to 20 percent solids to an area landfill.

Performance has been exceptional. “The facility has had no compliance violations during the two years preceding the Plant of the Year award,” says Baldwin. “It exceeds the requirement of having satisfactory systems of historical records and annual reports.” The city also maintains a well-documented safety program and has had no reportable lost-time accidents in the past year.

Baldwin maintains her Texas Commission on Environmental Quality licensure as a Class C wastewater treatment operator, and Class C water operator. Faiello maintains Class A licensure in water and wastewater, and Duke Wade, utilities supervisor, holds a Class C wastewater operator license.

Building toward excellence

The road to award-winning plant operations really started in 2008. “The turnaround in this facility started with improvements in our in-house laboratory process control procedures, the acquisition of the proper equipment to do so, and staff development,” says Faiello.

“Through Gretchen’s efforts and diligence, our facility has undergone a major revitalization in performance, asset management and protection, and aesthetics. Gretchen has taken ownership of her duties and of this facility, and it shows in every aspect of the plant operations and maintenance.”

Process control was job one. “Previously, the laboratory was not really being used for process control,” says Faiello. Other than a settleometer, there wasn’t much equipment on site. Critical samples were sent out to a contract lab, which meant the staff was at least a week behind in monitoring process conditions. “We didn’t know what the conditions were until we received results back from the lab,” Faiello says.

Faiello purchased the equipment necessary to perform in-house process control tests. He personally trained the staff and sent them to classes on how to use the instruments. Now, Willis performs daily process control testing in the lab and adjusts the treatment process as needed.

Other improvements followed, enhancing treatment and yielding operational savings.

Attention to detail

“The chlorination system was manual,” Faiello recalls. “It was ‘set it and forget it.’ But the flow varied, and the chlorination system was not monitored 24/7, so there was nobody there to make necessary adjustments. We were struggling with chlorination issues, and while we managed to stay in compliance, it was a daily struggle to do so.”

In early 2009, Faiello recommended and received approval from the Willis city council to purchase an automated chlorine dosing system. “It’s been a wonderful blessing,” he says. “We also installed a refrigerated composite sampler [Hach Company – Flow Products & Services], eliminating the need to rely on grab samples done by hand.”

Flow control and plant performance have been further improved through regular cleaning of lift stations, manholes, traps and the influent wet well. The plant went to regular quarterly cleaning using an outside contractor with vacuum trucks. “We began routine preventive maintenance, rather than waiting for a problem to occur,” Faiello says.

Since then, the city has purchased its own vacuum truck: “The cleaning has improved our plant operations dramatically, as well as our overall effluent quality.” The funds once used to hire the cleaning contractor now are applied to the regular plant operations budget.

In the biosolids area, cake moisture has been reduced and hauling costs saved through fine-tuning of the belt filter press. “The steering pistons that keep the belt aligned needed work,” says Faiello. “We fixed that, as well as the proximity switches and the belt itself. “

In addition, the previous polymer feed pump for the belt filter press was a simple diaphragm-style pump. The staff replaced it with a peristaltic feed pump, which has been much more reliable. “We’re using less polymer, yet getting good cake solids,” Baldwin says.

Other changes have also made a difference. “For all in-plant water, we now use plant effluent,” Faiello says. “And we have made a habit of using protective coatings on everything. All structures are painted, up to and including our standby generators. We’re preserving our assets against corrosion, and improving their longevity.”

Tightening down flows

The improvements at the plant and in the collection system have made the city less dependent on an old arrangement that diverted high flows to the neighboring city of Conroe for treatment.

“The interconnect has been in place for some time, and it was implemented as a means for peak shaving,” says Faiello.

“We had a significant infiltration and inflow problem, and heavy rains sometimes resulted in flows beyond the permitted capacity of our treatment plant. We still use the interconnect, but with our sewer improvements, we don’t need it as much for high flows.” Flow still passes to Conroe when the Willis plant is taken down for maintenance of the oxidation ditch or wet well. It’s a luxury to have available, but the city saves money by using it less often.

When Willis won the Plant Excellence Award, WEAT president John Bennett noted that the plant has not only always been in compliance, but also “looks beautiful.” That’s by design.

Faiello observes, “To some people, a wastewater treatment plant doesn’t have to look good and be clean because it’s a wastewater plant — there’s bacteria everywhere. I believe because it’s a wastewater treatment plant with bacteria everywhere, that’s all the more reason for it to be clean.”

And the improvements and fix-ups don’t have to cost a fortune. “While we’ve made changes and optimized processes over the last five years,” says Faiello, “our operations budget has actually been reduced.” They’re doing more with less.  

More Information

Aeration Industries International - 800/328-8287 - www.aireo2.com

Alfa Laval Ashbrook Simon-Hartley - 800/362-9041 - www.alfalaval.us/wastewater

Chemical Injection Technologies, Inc. - 772/461-0666 - www.chlorinators.com

Hach Company - Flow Products & Services - 800/368-2723 - www.hachflow.com

Hoffman & Lamson, Gardner Denver Products - 866/238-6393 - www.hoffmanandlamson.com

WesTech Engineering, Inc. - 801/265-1000 - www.westech-inc.com


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