City of Quinlan
Path to Compliance
The City
Railroad Crew - Quinlan, Texas
The community of Quinlan was established in 1892 as a depot stop along the Texas Central Railroad. The new community took its name from George Austin Quinlan, vice president and general manager of the Houston and Texas Central Railway.
By 1925 Quinlan had established itself as a retail trade center for southern Hunt, northern Kaufman, and Van Zandt counties. Oil exploration and production overtook cotton farming as the area's economic base in the 1930s and 1940s, and the construction of Lake Tawakoni in the 1950s brought another economic boost to the community. (Texas Historical Commission)
Today, Quinlan is very developed for a community of its size with a population of 1,470 and is one of the smallest cities that has a full-sized Walmart Supercenter and a full-sized Brookshire's grocery store.
USA NAIP Imagery
The System
City of Quinlan Clarifier
On October 31, 1994, the City of Quinlan obtained their wastewater permit for public domestic wastewater treatment. The permit is set for an average flow design of 0.3 MGD.
In 2017, the Texas Water Development Board approved financial assistance in the amount of $1,890,000 from the Clean Water State Revolving Fund to the City of Quinlan (Hunt County). The City used the assistance to complete finance planning, design, and construction costs associated with wastewater system improvements. The facility consists of two separate “bullseye” activated sludge wastewater treatment plants, three centrifugal blowers, one sludge drying box, three drying beds and gaseous chlorination facilities.
The Assistance Request
In March of 2022, Tyler Davis, Public Works Director contacted TRWA concerning wastewater plant operations. Scott Willeford, TRWA responded to his request for assistance and scheduled a date to meet and view the facilities.
Mr. Willeford arrived on March 14, 2022, to tour the plant and review the plant’s data. Mr. Willeford met with Tyler Davis - Public Works Director, David Sechrest - Class C Licensed Operator, Dillon Russell - Class D Licensed Operator, Buddy Scott - Crew Leader, Bryant Stanford - Crew Leader, Julio Vasquez - Maintenance Worker, and Joe Owen - Utility/Plant Operator to determine concerns with operations of the system’s wastewater treatment facility.
Mr. Willeford toured the facilities and noticed several issues that directly affected the proper treatment of the wastewater which led to multiple permit violations. Mr. Willeford reviewed the system’s collected data pertaining to current permit parameters. Researching Texas Commission on Environmental Quality’s (TCEQ) database, Mr. Willeford found 32 ‘failure to meet the limit for one or more permit parameter’ violations starting in January of 2018.
The Issues
Upon visual inspection of the facilities and reviewing data collected by the operators, Mr. Willeford identified five (5) major areas of concern.
- The sludge inventory on both trains were 10,000-12,000 Mixed Liquor Suspended Solids (MLSS) with 8-10 ft. sludge depth. The aeration basins had excessive foam with a gray-black color, indicative of high solids.
- The dissolved oxygen levels in both trains were <1 mg/l. Dissolved oxygen levels in the aeration tank must be maintained at 1-3 mg/L for effective treatment. Low levels of DO will result in the death of the microbial biomass, which is timely and expensive to reestablish.
- The bar screen was inadequate, allowing rags and larger material into the plant. This not only has a negative impact on the mechanical processes of the plant such as pumps but impedes the ability of the treatment process to work effectively.
- The drying beds were nonfunctional, causing the system to depend on a sludge box for sludge removal. This issue resulted in excessive solids in the plant and causing the city to not meet permit.
- The plant was violating Biochemical Oxygen Demand (BOD5) and Total Suspended Solids (TSS), both average and single grab. The plant has a “report only” designation on the Nitrogen Ammonia (NH3). However, the system data indicated considerable amounts (mg/l) and would be considered permit violations if mandated on permit.
Findings at the plant
The Resolution
After evaluating the City's plant, Mr. Willeford recommended the following actions to assist in getting the plant back into compliance.
1. The plant needs to increase wasting to reduce the MLSS to a 3000-5000 mg/l. Mr. Willeford cautioned the operators that this should be done gradually in order to monitor the impacts on the plant.
2. Conduct preventative maintenance on blowers. Once solids in the plant decrease, the Dissolved Oxygen (DO) levels will increase.
3. Replace bar screen with a new stainless steel screen to prevent from rusting and corrosion.
4. Rehabilitate the drying beds to make them functional as designed. With the plant increasing waste to maintain MLSS ranges, the drying beds will be crucial to plant efficiency.
5. Once the solids and DO are within proper levels, BOD, TSS, and NH3 will return to compliance. Conduct 30-minute settable test and monitor DO levels in aeration basins daily.
Mr. Willeford received periodic updates from Mr. Davis over the last 8 months concerning plant operations and lab data. Mr. Willeford worked with Mr. Davis on his concerns and provided guidance. Mr. Willeford made a visit on June 9, 2022 and toured the plant. Mr. Willeford found the plant responding to his recommendations. The MLSS in the aeration basins were still higher than recommended, but the operator’s response to the issues were exceptional and the plant continues to improve.
Treatment Quality is Improving
In July 2022, Mr. Davis reported to Mr. Willeford that the bar screen had been replaced and drying beds had been rehabbed. Mr. Davis stated the drying beds were functional and being utilized. Mr. Davis explained the plant started to turn around in June 2022 with only E-Coli violations due to chlorine issue. Mr. Davis stated the plant had regained total compliance in July 2022.
Mr. Willeford has continued to monitor the monthly lab data for the system and the results have been exceptional. According to the WWTP Discharge Monitoring Reports (DMR), the system has been permit compliant from July-November 2022.
Mr. Willeford praised the team from the City of Quinlan on their accomplishments regarding the work at the WWTP. Mr. Willeford encouraged the group to continue their efforts to reduce/maintain the sludge inventory which will keep the plant in compliance. Mr. Willeford explained that their efforts responding to the former condition of the WWTP were extraordinary and conveyed his services would always be available.
Texas Rural Water Association
TRWA recognizes the importance of programs like EPA’s Training and Technical Assistance program and the impact it makes on utilities across the nation. The City of Quinlan is an example of the benefits programs dedicated to providing onsite assistance have on struggling utilities and new operators.
