The City of Brownwood is working to redesign and convert the city’s waste water treatment plant to a more efficient and upgraded state, which began with an impressive demolition project recently.
Last week, city crews worked with Crane Services of Sweetwater and engineer Doug Hearne to complete the first steps of demolition needed for the approximately $2.5 million project, removing the 60’ wide lid from the circular anaerobic digestor tank.
Crews worked for several hours to remove the lid that originally floated on top of the sludge-filled tank, which worked similar to a septic tank reducing solids in the water coming into the plant. A delicate operation of hooking up the huge lid to the crane was completed on Monday which will allow the tank to be converted to an aerobic digestor. This change required removal of the lid, paddles, and its workings which in the winter heated the sludge to help keep the bacteria within the tank active. With the aerobic conversion, the tank will have blowers and fine bubble diffusers added that will increase the efficiency of oxygen transfer in the biological process, according to Director of Public Works David Harris and Hearne. The huge metal lid will be cut into smaller pieces and recycled, and funds received will be utilized in the project. Another savings to the city comes from the repurposing of the small building which was a boiler room for the anaerobic digestor into a new control room for the digestor when it is converted to an aerobic digestor. This will save the city $10,000-15,000, according to Harris.
The hiring of Crane Services to remove the lid and the initial preparatory work done by city employees at the plant saved the City of Brownwood approximately $15,000-$20,000, according to Harris. City crews will complete other portions of the project such as digging ditches and laying pipelines within the plant will save an additional $3000-$4000.
This redesign of the waste water treatment plant adds biological treatment with the addition of phosphorous and nitrogen for future licensing purposing. By this redesign, the environment within the plant becomes more suitable for bacteria, which is more conducive to the type of treatment. This treatment also cuts costs for the city in that there will be less chemicals and less sludge involved in the process of treatment, resulting in less cost of chemical purchased as well as lowering the cost of hauling sludge to the landfill. The electrical cost to run the plant will also be reduced after the redesign is completed.
Harris summed up the reason for the work.
“The current treatment process at the waste water treatment plant is extended aeration. The plant will still operate in this mode, but we’re going to increase the ability to remove trash and untreatable items at the beginning,” said Harris. “This will increase the efficiency of the biological process and increase efficiency of the sludge removal process.”
In addition to the redesign to a more effective plant, some of the changes that will be made are due to the age of the plant and some of its parts as well as new Texas Commission on Environmental Quality (TCEQ) requirements for licensing. Plants such as this one are inspected once every 5 years, according to Harris.
“The plant rehab in 1992 didn’t do as much as should have been done because of funding. Now we are working on some things, replacing because they are just old,” said Harris. “It’s something we have to do. A lot of the plant is worn out.”
Harris explained that some of the antiquated parts of the plant have had to be rebuilt or repurposed to keep the plant working due to the age of these parts.
It will be approximately 2-3 months before the contractor starts on the wastewater plant conversion and redesign as plans for the work are not finalized. There are some parts of the redesign that will depend on whether or not the city moves forward on the water reuse plant.
If the water reuse project is approved and plans move forward for its construction, the city crews will lay pipelines from the waste water treatment plant to the reuse plant, a distance of approximately 5800 feet, which will be a savings of about $500,000 in the reuse plant’s construction costs. Harris stated that any city labor, repurposing and reuse of materials will be used when possible to help eliminate costs from the city’s budget for these projects.
The City of Brownwood revisited discussion on the water reuse plant during last week’s city council meeting; however being a discussion only item, no action could be taken.
Harris explained that he is not worried about the safety or the quality of the end result water from the planned reuse plant because of the current quality of the water that flows out of the waste water plant. He explained that many of the chemicals, related to the medical field and farming, are tested for in the current plant and show as non-detectible levels.
“Reverse osmosis takes out harmful chemicals, many we don’t even have in the end product of the waste water treatment plant,” said Harris. “Some metals and minerals are necessary for good health but too much of them can kill you, so we test for all of them (good and bad).”
Harris once again endorsed the safety of the reuse plant.
“The waste water treatment plant end product water meets the standards of TCEQ in everything, with the exception of nitrates, which the reverse osmosis (RO) will be used to remove 95-98%,” said Harris. “The reuse plant is designed to treat all the things that TCEQ requires.”
The City of Brownwood has been under Stage 3 water restrictions for nearly 3 years. The Brownwood City Council will take up the matter again in the next few weeks for possible action on the reuse plant.
Pictured above is the lid of the digestor as it was removed from the tank on Monday, April 7th. Below are more photos of the demolition project.
Attaching the crane to the motor of the old digestor
The motor is pulled from the digestor.
Crane operator concentrates while moving the huge motor.
Cables are attached to the lid for removal.
Portions of the lid were cut away during the removal the project.
Lifting the massive lid from the tank.
