Garry Houston and his team in Abilene conquer source water challenges in getting the most from a microfiltration water treatment plant.
Wanting to know the “why” behind everything has dominated Garry Houston’s life. When hired to work at the newly completed microfiltration Hargesheimer Water Treatment Plant in 2003, Houston rapidly absorbed the training and gained the experience to earn a water Operator IV (highest) rating from the city of Abilene and a Texas Class A (highest) water operator license.
“The other operators have been here three to five years, so they depend on me to learn the peculiarities or technicalities of the different equipment,” says Houston. “They also know I will not settle for second-best. Either they do it correctly or they aren’t going to work for me.”
Rodney Taylor, director of Water Utilities, says Houston readily shares his knowledge with co-workers through mentoring and training, and takes great pride in running a tight ship. “Garry assumed a leadership role early in his career as operators struggled with the sometimes fickle membranes while receiving little outside support,” says Taylor.
Richard Williams, Water Treatment Division program manager, nominated Houston for the 2016 Outstanding Plant Operator Award from the South Central Membrane Association. Williams wrote on the nomination form, “Garry has been a positive influence to our organization from the day he was hired. He’s on call 24 hours a day and is someone the city can always count on.”
Houston says, “I consider the award a great honor because it comes from my peers; but truthfully, I’m just doing my best at a job I love.”
The 6 mgd (design) Hargesheimer plant draws raw water into a 36-inch main using three vertical turbine pumps on Lake O.H. Ivie. Raw water travels 43 miles to a 6-million-gallon booster station, then to a 10-million-gallon feed tank at Ovalo.
As water gravity flows the remaining 9 miles to the plant, it receives injections of chlorine dioxide to oxidize iron and manganese. At the plant’s raw water vault, injectors feed 20 ppm of ferric sulfate coagulant to the static mixer.
Water entering the plant flows through three strainers with 40- by 40-inch stainless steel wire mesh cones, and then to six microfiltration racks (Pall Corporation) each holding 92 modules with 0.1-micron polyvinylidene fluoride hollow-fiber membranes. Feedwater enters the bottoms of the modules, passes through the membranes, and exits as permeate through the tops. Membranes are backflushed every 30 to 60 minutes, interrupting forward flow for 2.5 minutes.
Permeate flows to a concrete break tank. A portion of the water flows to one of two 1.5 mgd reverse osmosis trains (Advanced Environmental Water Technologies) to remove sodium, chloride and sulfate. The two-stage RO trains have 24 vessels in the first stage and 12 in the second. Each vessel holds seven energy-saving polyamide 2-LD filters (Hydranautics, a Nitto Group Company) set for 75 percent recovery. The resulting concentrate goes to a third-stage concentrator (H2O Innovation) set at 58 percent recovery.
The remaining permeate in the break tank is blended with microfiltrate, flows to the blended water vault, and is treated with free chlorine gas before the static mixer. After disinfection in a 100-foot-long 60-inch pipe, the water is finished with liquid ammonium sulfate, caustic and fluoride before flowing to a 5-million-gallon clearwell storage tank for distribution through 934 miles of mains to more than 40,000 customers.
An upgrade now in progress will increase plant capacity to 12 mgd. Besides replacing the third-stage concentrator (now operational) and adding two 7.5 mgd microfiltration racks, improvements include a cascade for aeration, two flocculation basins, and two sedimentation basins with incline plate settlers and automatic sludge collection rakes (both from Jim Myers & Sons). A belt press (BDP Industries) will dewater sludge before offsite disposal.
The plant is manned 10 hours per day. Houston works with Operator III Justin Brickey (Class A license), and Operators I Michael Ingram (Class C license), Chase Hoyt, Fay Couture and Will Thompson (D license). Kenny Hutchins is the utility system manager.
Drought and Abilene’s huge demand for water in summer complicated the plant upgrade. Houston and the construction contractor spoke daily to coordinate shutdowns, as the city’s conventional Grimes and Northeast water treatment plants needed time to increase production.
“Our plant has automatic shutdown, so it takes 30 minutes to close the raw water valves and empty the lines or start back up,” says Houston. “The on-again-off-again schedule was hard on everyone, so we switched to running the plant once a week.”
Lake Ivie has high natural concentrations of iron and manganese, making it necessary for operators to flush the raw water intake lines before starting the plant. They also change the water in the Ovalo feed tank. “Every so often we’d open the blow-off, drain half the tank, and fill it with freshwater to dilute what had been sitting,” says Houston.
In early July 2015, operators shut the plant down to accelerate construction. It remained dormant until pretreatment startup in October 2016.
Lake Ivie’s natural characteristics are only half the equation. The reservoir, with 19,149 surface acres, holds 554,340 acre-feet. It was half full when Houston arrived 14 years ago. “Evaporation concentrates the iron and manganese, making them harder and harder to treat,” says Houston. “We’ve also had three freak rainstorms over the years that filled the lake to 25 or 30 percent. The massive runoff carried organic debris into the lake and churned up sediment.”
The Ovalo feed tank was the plant’s warning system. It takes a day and a half for water to flow from it to the plant. Both are sampled daily. “When Ovalo has a bad sample, we prepare for the dirty water by adjusting chemical doses,” says Houston. “Once the lake calms down, treatment returns to normal.”
In 2007, with the Lake Ivie level at 11 percent, mineral concentrations were so high that they stopped up the membranes. Although operators cleaned them with citric acid, the plant was barely running. Wanting to know why, Houston pulled a membrane and sent it to Pall Corporation for an autopsy. “It showed the water was full of iron,” he says. “We needed a stronger cleaning solution, and Pall sent sulfuric acid.” Multiple applications finally cleaned the membranes, enabling operators to maintain them with citric acid.
In 2012, the lake level reached 30 percent, then headed back down again. “Sure enough, the membranes stopped up,” says Houston. “This time, the autopsy showed organics were at fault. We were using caustic and bleach to clean the membranes, but Pall said our solution needed to be much stronger. That worked.”
In 2015, clogged membranes almost brought the plant to its third standstill. To uncover which membranes in the six racks were at fault, Houston asked his operators to put their hands on them during the air scour cycle in the backwash. Those that didn’t shake were pulled and weighed. “New membranes weigh 65 pounds, but clogged ones weigh as much as 95 pounds,” says Houston. The autopsy revealed iron and organics as the culprits.
The operators had learned they didn’t need sulfuric acid to clean clogged membranes if they used much stronger citric acid, caustic and bleach. They called it super-cleaning as opposed to maintenance cleaning. It took a week to super-clean a rack with 92 filters. Then they repeated the six-week process to fully restore the membranes. To be on the safe side, they super-cleaned a third time.
“We wanted to produce more water to take some pressure off the Grimes and Northeast plants, but doing so without pretreatment would simply stop up the membranes faster,” says Houston. “The upgrade with pretreatment will bring cleaner water into the plant and extend the life of the membranes.”
Hargesheimer was not the first water treatment plant using membrane technology in Texas, but it was an early entry. “Garry is a very important player in the success of our overall water treatment strategy,” says Taylor. “He’s self-motivated and a go-getter. Garry found answers to our early problems by establishing a network of peers from throughout the industry, and he regularly exchanges information on how to resolve technological issues.”
Houston, who turned 60 in January 2016, hopes to stay at his post another 10 years. “Even after 14 years, I’m always learning something new,” he says. “I love the challenge of treating water with very undesirable characteristics, and the water is always different.”
Food for thought
Garry Houston had no idea what delights he was missing by sticking to chicken-fried steak and Texas-style barbecue. Then Houston, senior plant operator at the Hargesheimer Water Treatment Plant, found the Yelp website while searching for a Dallas restaurant. Yelp publishes crowd-sourced reviews about local businesses.
“My hobbies are playing golf and eating out,” says Houston. “I downloaded the free Yelp app and was hooked. Here was instant access to thousands of people’s opinions of different places, events, nightlife, bars. The list is extensive.”
Before long, Houston wrote his first restaurant review. Then he began reviewing everywhere he went and everything he did. Since February 2011, he has written
654 reviews and posted 817 photos. “There’s no remuneration and no freebies,” he says. “I just do it for fun.”
Averaging 130 reviews per year, he quickly exhausted most of the restaurants, business and home services in Abilene. So he headed toward Fort Worth and Dallas. Tired of ordering the same meals and eager to try something new, he ventured into dishes from different cultures. “German and Thai are my favorite cuisines,” he says. “Next on the list is Korean food.”
Yelp has community managers in all major cities who review applications to join its Elite Squad, a group of active members recognized for providing quality information. In 2015, Houston’s application was accepted. He has retained his Elite Squad status.