Every day, the Lower Stroubles Creek waste water treatment plant (5277 Prices Fork Road) treats approximately 6 million gallons of wastewater that comes down the drains of bathrooms, kitchens, streets of the houses, schools and businesses of the Blacksburg, Virginia Tech, and surrounding areas in Montgomery County. That’s about six –football-fields, 10 feet deep every day.
Barely fifty years ago, many American cities simply dumped raw sewage directly into nearby water bodies like the New, contaminating drinking water and killing wildlife. Regulation now requires governments to treat wastewater, but what’s left over after the water’s been cleaned is the solids, everything that’s taken out of the dirty water before sending the clean water into the New River.
Those solids are often still contaminated with bacteria and viruses that can only be incinerated or buried in a landfill, but extensively treated solids, called biosolids, can be applied to land as fertilizer.
The Blacksburg-VPI Sanitation Authority is the first in Commonwealth to produce Class-A biosolids – treated solids – using advanced treatment process called Autothermal Thermophilic Aerobic Digestion process to produce Class A Exceptional Quality biosolids.
After ATAD treatment, Class A biosolids meet “the most stringent federal and state requirements and can be used in a wide range of applications, including as a soil amendment, use in landscaping, and as a lawn or agricultural nutrient.
The ATAD is an advanced treatment process that uses high temperatures generated by the biosolids themselves to kill pathogens and reduce odors in wastewater solids.
“A specific type of bacteria that thrive in very hot environments are grown in the ATAD tanks. They produce a lot of heat that kill bacteria and viruses,” Lawrence Hoffman, associate vice president of the design engineer CHA Consulting Inc. said. “Most waste water treatment facilities produce Class-B biosolids. The fecal coliform level allowed for Class B is about 2 million per gram, but, for Class A, the limit is 1000 fecal coliform bacteria per gram,” Hoffman said.
Installation of the ATAD treatment facilities was made possible through a $13.3 million dollar investment from the authority. The new ATAD facilities replace the solids incinerator that was constructed when the treatment plant was first built in 1979 and required the authority to purchase, store and use thousands of gallons of fuel oil each year.
The investment makes sense as a significant improvement in the quality of material produced, anticipating more stringent biosolids use regulations, and the purchase of an advanced process the authority said.
“We initially may have a small savings, but we replaced a 40-year-old system and we’re not spending any more money.” Michael Vaught, Executive Director Blacksburg-V.P.I. Sanitation Authority said. “The new process represents a significant improvement in our solids treatment and handling processes by eliminating the need for incinerator fuel, significantly reducing our air emissions, and providing opportunities for a variety of beneficial uses for the treated biosolids.”
The ATAD facilities were designed to accommodate future population and enrollment growth.
“The plant is designed to process 9 million gallons a day,” Vaught said, “and we’re currently at 6 million gallons, so we can accept a 50 percent increase.”
Getting the ATAD facility Class A certified required two years and extensive testing from the Virginia Department of Environmental Quality.
“The system has been in operation for two years with an extensive testing program to complete to be classified as a Class A. This being the first facility, so the DEQ wanted to come down and inspect and learn more about it,” Vaught said.
The authority is a partnership among the Town of Blacksburg, Virginia Tech, and the Blacksburg-V.P.I. Sanitation Authority.
Dr. Sherwood Wilson, vice president for operations at Virginia Tech and authority board member said choosing to install the ATAD system part of a larger pledge to find innovative and sustainable ways to deliver public services.
“The decision to invest in the ATAD system reinforces the town and Virginia Tech’s commitment to sustainability through implementing state of the art processes which add value both fiscally and environmentally to our community,” said Blacksburg Deputy Town Manager and authority board member Chris Lawrence.
Currently, the authority provides the four dump truck loads of biosolids a day to the New River Resource Authority landfill for use as a daily cover material reducing the amount of natural soil excavated from areas near the landfill to cover trash.
But, the biosolids generated now are of a sufficiently high quality that they may be made available to farmers, landscapers, and for use in composting.
“We are just now getting into the marketing stage of this and we haven’t made a decision yet. We’re looking at all options,” Vaught said.
— Virginia Tech