2019 Excellence in Environmental Engineering and Science® Awards Competition Winner

Grand Prize - Small Firms

Town of Moorefield/Hardy County Regional WWTP Upgrade with the MOB® Process

Entrant: Nuvoda, LLC
Engineer in Charge: Jason Calhoun, P.E.
Location: Moorefield, West Virginia
Media Contact: Sage Chang

Entrant Profile

Nuvoda, LLC is an environmental engineering company dedicated to innovative, sustainable and renewable wastewater technologies geared directly towards water reuse. Headquartered in Raleigh, NC with a R&D department located in Blacksburg, VA, Nuvoda's core competency lies in researching, developing, manufacturing, integrating and delivering industry leading, cutting-edge biofilm and granular technologies. From industrial to municipal, Nuvoda has clients throughout north America and has continued to solve the most pressing issues faced by modern wastewater treatment systems.

The Moorefield/Hardy Regional WWTP was constructed in 2013 as an effort to preserve the Chesapeake Bay Watershed. The project was a collaboration between the town and poultry giant JBS Pilgrim's – a major local employer. However, because the WWTP receives 90% of its influent from the industrial process, the imbalanced nutrient and flow level often impacted the biological treatment performance and stressed operational cost.

To help reduce operation cost, system upsets and improve treatment efficiency, Nuvoda engineers proposed a full upgrade in 2017 using the company's patented Mobile Organic Biofilm (MOB®) Process. Nuvoda provided the engineering design plans, oversaw the construction and manufactured the necessary components for the MOB® process. Crismon Construction was the contractor. The upgrade took 3 months to complete and was finished in March 2017.

Project Description

Moorefield/Hardy Regional WWTP Challenges

Complexity

In 2013, a partnership between the Town of Moorefield, West Virginia and a local JBS Pilgrim's poultry manufacturing facility resulted in the construction of the 4.1 MGD Advanced Nutrient Wastewater Treatment Plant (WWTP) to improve the region's discharge quality into the Chesapeake Bay Watershed. The treatment facility's state-of-the-art 5-stage Bardenpho biological treatment process handles 90% industrial and 10% municipal influent to meet the stringent discharge limits (total nitrogen, TN = 51,431 lb/yr; total phosphorus, TP = 5,221 lb/yr). However, soon after start-up, the Moorefield/Hardy WWTP encountered multiple issues caused by the waste flow from the poultry process. The industrial influent's high but variable nutrient levels and flow rate and lack of BOD have cost the WWTP an average of $13,000 a month in additives, and at least 4 major system upsets caused by sanitation chemicals in 2016, costing the WWTP $200,000 to recover.

The MOB® Process Upgrade

To reduce operation cost, system upsets and improve treatment efficiency, Nuvoda proposed a full upgrade with the company's patented Mobile Organic Biofilm (MOB®) Process.

Originality and Innovation

The MOB® process is an innovative and sustainable wastewater treatment process developed by Nuvoda to address stringent nutrient removal levels, settleability issues, and limitations of reactor footprint and configuration. The patented MOB® process utilizes kenaf core, a renewable lignocellulosic material harvested from the fast growing kenaf plant (Hibiscus cannabinus), as a substratum for fixed-film growth in biological nutrient removal (BNR) processes. The porous kenaf particles are machined to approximately 500 µm in size with estimated specific surface area (SSA) larger than 20,000 m-1 (K1 media SSA ~ 1,000 m^-1). When compared to traditional activated sludge and fixed-film processes, the high SSA of kenaf media supports high concentration of biofilm growth, which significantly shortens SRT and minimizes occupation of reactor volume while achieving the same or higher level of nutrient removal rate. When the biofilm is fully developed, the kenaf media acts like granular sludge that harbors stratified microbial community for simultaneous BNR with high settleability, and is free to circulate into the secondary clarifiers to improve SVI. The "mobile" and granular-sludge-like property of kenaf media eliminates the need for extensive screen installation, reduces down time during upgrade, retrofits into almost any treatment plant configurations, and is a more time and cost effective alternative to the actual granular sludge systems.

Integrated Project

The MOB® Process upgrade for the Moorefield/Hardy WWTP consisted of 60 ton of kenaf media added to the 4.1 MGD 5-stage bioreactor, a 300 GPM drum screen for kenaf media recycling, RAS lines, and a belt-press sludge dewatering system. The goal was not only to provide the highest performance system for the protection of the local aquatic environment, air quality (reducing odor) and soil health, but also consider the client's financial and down-time budget. Nuvoda was able to supply a high-performance treatment process with minimal modifications to the existing plant that took only 3 months to complete, and develop a waste disposal strategy for the client that help reduce sludge handling cost and landfill stress through efficient dewatering, or increase value of the waste through an upcycling composting plan.

Click images to enlarge in separate window.


Lignocellulosic Kenaf core is machined to 500 µm in size to serve as biofilm carriers. The plant- based material is renewable, long-lasting (annual loss rate <2%), and partially offsets the carbon footprint from wastewater treatment processes.	The porous kenaf media supports thick biofilm growth. The sample was harvested from the Moorefield WWTP in August 2018, about 1.5 years after the MOB® upgrade.

Kenaf has excellent settleability (bottom darker layer; lighter layer is MLSS) and can circulate into the secondary clarifiers to improve SVI. The pilot reactor shown is housed in the Nuvoda's R&D lab for on-going research efforts.	The Moorefield/Hardy Regional WWTP was constructed in 2013 as an effort to preserve the Chesapeake watershed. Nuvoda proposed a full MOB® upgrade in 2017 to help increase treatment performance and reduce operation cost. The picture was taken after the upgrade was complete, with a new shed housing the drum screen at the end of the oxidation ditch, a new building housing the belt press for sludge handling, and the addition of kenaf media in the oxidation ditch.

Moorefield wastewater treatment process overview and Nuvoda's upgrades. The original treatment process includes a rake bar screen to separate large debris from going into the treatment train, two parallel primary clarifier, two parallel 5-Stage oxidation ditches, 2 parallel secondary clarifiers, aerated sludge holding tanks and sludge dewatering station. Nuvoda's upgrades include kenaf addition into the 5-stage oxidation ditches, a rotary screen for kenaf recycling, a RAS holding tank and pumps to return the kenaf media in the oxidation ditches, and a belt press dewatering system.	Monthly cost breakdown of the Moorefield WWTP a year before and after the upgrade. The MOB® Process installed in March 2017 has reduced the total monthly cost as well as individual costs in electricity, sodium aluminate, and belt press polymer usage. More noticeably, the MOB® process has been resilient to harsh influent conditions and has eliminated major system upsets since its completion in March 2017.

Monthly average solid retention time (SRT) a year before and after the upgrade. The MOB® system consistently decreased the SRT from 25 days to 5 days since the installation in March 2017. Kenaf media's high SSA can support concentrated biofilm growth, thus increases the treatment capacity by at least 75% within the same reactor configuration.	30-min Sludge Volume Index (SVI30) and Effluent TSS improved significantly from an average of 460 mg/L and 90 mg/L to an average of 60 mg/L and 4 mg/L, respectively since March 2017.

Sludge blanket thickness in the secondary clarifiers decreased to lower than 1 ft from an average of 11 ft since March 2017.	TP removal cost for Moorefield since 2014. The cost steadily decreased as the treatment plant stabilized throughout the years. However, with MOB® implementation, the cost reduced further below $1/lb in 2018 (38% lower compared to 2016).

Fluorescent in situ hybridization (FISH) probe NSO190 (red) shows microcolonies of Nitrosomonas developing in the aerobic zones, facilitating nitrification process.	Cy3 labeled FISH probe PAOmix (green) indicates PAOs harbored within the MOB® system.