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The Facultative Membrane BioReactor (FMBR)

The Facultative Membrane BioReactor (FMBR)

The Facultative Membrane BioReactor (FMBR)

The FMBR is a one-step, single tank solution for on-site wastewater collection, treatment and reclaimed water, suitable for commercial and residential areas, watershed pollution protection, and wastewater treatment plant upgrading. Compared to traditional sequencing batch reactors (SBR) and MBR systems, it operates with low energy and a small footprint. These design characteristics make for an efficient Decentralized Wastewater Treatment System (DEWATS). The FMBR is also designed for large scale centralized WWT systems and upgrades and has many proven examples.

FMBR was invented by Jiangxi JDL Environmental Protection Co., Ltd. (JDL) of Nanchang, China in 2008. JDL claims 47 invention patents across the USA, UK, France, Japan, China, and other countries, and over 3,000 systems installed and commissioned across 19 countries.

The ecosystem cultivated by an FMBR is designed to have the characteristics of a high concentration of microbes, long Solids Retention Time (SRT), and low Dissolved Oxygen (DO), which enables simultaneously removal of Carbon (C), Nitrogen (N), Phosphorus (P), and organic residual sludge in one reactor.

In the below 9 minute video, I present a summary of the FMBR on behalf of JDL for the New England Water Environment Association (NEWEA) in January of 2022.

FMBR Pilot Demonstration Project

The first FMBR Pilot Demonstration Project installed in the USA was in November 2019 at the Plymouth, Massachusetts Municipal Airport. This was made possible by winning a global competition hosted by the Massachusetts Clean Energy Center (MASSCEC) for wastewater treatment innovations that minimize energy consumption. It was granted the highest available funding of $150,000. The final report summarizing the results of the pilot can be found here: (FMBR Pilot: Final Report).

The FMBR Pilot was selected to replace an SBR wastewater treatment process due to high energy costs. The FMBR was sized to process 5,000 gallons per day (GPD) of wastewater generated by the airport and surrounding restaurants. Effluent discharge permit requirements were: Biological Oxygen Demand (BOD) < 30 mg/L, Total Nitrogen (TN) < 10 mgN/L, and Total Suspended Solids (TSS) < 30 mg/L.

Daily testing of influent and effluent for TN, P, BOD, and TSS showed strong performance of C, N, and P removal. Over one year of operation, the FMBR Pilot observed average daily P removal of: 10.0 mgP/L to <1.0 mgP/L; TN removal: 62.7 mgN/L to 4.1 mgN/L; BOD removal: 371 mg/L to non-detect; and TSS removal: 79 mg/L to non-detect.

As compared to the legacy SBR system (25K GPD capacity), the FMBR Pilot energy savings was estimated @ 70%, although on an “apples to apples” comparison to the SBR, the estimated energy savings was ~30%. Annual volume of biosolids requiring offsite disposal was reduced by an estimated 65%. Footprint was reduced by 75%. Installation and commissioning of the FMBR Pilot system was completed in 30 days.

DNA Study of FMBR Microbiome

Microbe Detectives analyzed 13 samples of the FMBR Pilot’s biology collected between May 2020 and May 2021 to help JDL better identify and quantify the FMBR Pilot’s nutrient removal biology. 16S DNA sequencing methods specialized for wastewater BNR analysis were applied. Results on the first 3 samples revealed Tetrasphaera at a high abundance. Tetrasphaera is a Denitrifying Phosphorus Accumulating Organism (DPAO), that can ferment, produce Volatile Fatty Acids (VFAs), and has shown to be a very robust PAO. Bacteria capable of Simultaneous Nitrification/Denitrification (SND) including Dechloromonas, Pseudomonas, and Thauera, were observed coexisting in the same facultative environment.

In a 2nd phase project, statistical summaries of the presence and abundance of BNR microbes observed in FMBR Pilot samples, were compared to 18 municipal wastewater BNR processes. These statistical summaries are referred to as “BNR benchmarks.” MD 16S DNA sequencing data of FMBR Pilot samples was aggregated with MD 16S sequencing database of 675 samples from 18 municipal wastewater BNR processes, that are dispersed across New England, Midwest, Southwest, Rocky Mountains, and West Coast geographies in the USA. All data was anonymized.

Key FMBR Microbes

Five BNR microbes were detected in all 13 FMBR samples. They include Tetrasphaera, Dechloromonas, Rhodocyclus, Nitrospira, and Pseudomonas. Each have known capabilities to remove C, N, and/or P.

Evidence of Simultaneous C, N, and P Removal

C – Removal

Fermenting bacteria remove C by decomposing organic waste and producing VFAs which is food for PAOs. The % abundance of Fermenting bacteria observed in FMBR Pilot samples averaged 4.2% vs 2.4% in BNR benchmarks. Tetrasphaera represented ~ 95% of fermenters and was identified in every FMBR sample.

N – Removal

An average 17.6% abundance of N – bacteria was observed in FMBR samples vs 6.3% in BNR benchmarks. Bacteria capable of SND represented 94% of N bacteria in FMBR samples.

Dechloromonas (avg. 8.3% in FMBR vs 1.0% in BNR benchmarks), Pseudomonas (avg. 8.1% in FMBR vs 3.1% in BNR benchmarks), and Tetrasphaera (avg. 4.0% in FMBR vs 2.4% in BNR benchmarks), were detected in all 13 FMBR samples, often at a relatively high % abundance. In other studies, Dechloromonas, a known phosphate-accumulating organism (PAO), has been observed in high abundance in alternating anoxic and aerobic conditions, enabling nitrification and denitrification (2, 3).

Pseudomonas has been observed to be capable of performing heterotrophic nitrification and then denitrify their nitrification products under aerobic conditions (4). Tetrasphaera is a Denitrifying Phosphorus Accumulating Organism (DPAO) that can decompose organic waste and produce VFAs, as a fermenting bacteria, and has shown to be a very robust PAO. DPAOs are of particular interest due to their ability to utilize internally stored cellular carbon both for P uptake and denitrification at the anoxic stage, resulting in increased phosphorus and nitrogen removal in BNR systems.

P – Removal

Phosphorus Accumulating Organisms (PAOs) were observed at an average 12.4% in FMBR Pilot samples vs 4.1% in BNR benchmarks. Overall PAO % abundance in FMBR samples was the highest among all benchmarks.

Key Missing Microbes

Key BNR microbes missing in FMBR samples, or at low levels, included Ammonia Oxidizing Bacteria (AOBs) (avg. 0.1%), Nitrite Oxidizing Bacteria (NOBs) (avg. 1.0%), and Nitrate Reducing Bacteria (NRBs) (avg. 0.1%). In a low DO SND condition, these microbes are expected to be missing because the environmental conditions are not suitable. This is additional evidence pointing to simultaneous nitrification/denitrification in a low DO condition as the principal N removal process of the FMBR.

Operating and Biological Data Tell the Same Story

Daily influent and effluent test data of C, TN, BOD, and TSS removal by the FMBR Pilot demonstrate strong nutrient removal capabilities. 16S DNA sequencing conducted in this analysis validates a high abundance of microbes that complete simultaneous nitrification/denitrification in a low DO condition, a high abundance of fermenters, that decompose organic waste and produce VFAs, and a high abundance of PAOs that biologically remove phosphorus. These processes occur simultaneously by facultative microbes that live in the same ecosystem, and compete for the same food. The significant energy savings is expected because of the low DO (<0.5 mg/L) condition. The reduction of biosolids production makes sense because of the greater abundance of fermenters that decompose organic waste and longer SRT. In the end, operational and biological data tell the same story – simultaneous removal of C, N, and P, in a single tank, with a surprisingly small amount of energy, footprint, and biosolids waste.

References

  1. Kristiansen, R., Nguyen, H., Saunders, A. et al. A metabolic model for members of the genus Tetrasphaera involved in enhanced biological phosphorus removal. ISME J 7, 543–554 (2013).
  2. Xu, D., Liu, S., Chen, Q. et al. Microbial community compositions in different functional zones of Carrousel oxidation ditch system for domestic wastewater treatment. AMB Expr 7, 40 (2017). https://doi.org/10.1186/s13568-017-0336-y
  3. Lifang Luo, Junqin Yao*, Weiguo Liu et al. “Comparison of bacterial communities and antibiotic resistance genes in oxidation ditches and membrane bioreactors,” Nature Portfolio, Scientific Reports (2021)
  4. Jin, R., Liu, T., Liu, G. et al. Simultaneous Heterotrophic Nitrification and Aerobic Denitrification by the Marine Origin Bacterium Pseudomonas sp. ADN-42. Appl Biochem Biotechnol 175, 2000–2011 (2015).
  5. Bergey’s Manual of Systematic Bacteriology, Edition Eight, by R.E. Buchanan and N.E. Gibbens, page 517.
  6. Strous M.; et al. “Deciphering the evolution and metabolism of an anammox bacterium from a community genome”. Nature. 440 (7085): 790–794. (2006).
  7. Lv, Xiao-Mei et al. “A comparative study of the bacterial community in denitrifying and traditional enhanced biological phosphorus removal processes.” Microbes and environments vol. 29(3): 261-268. (2014).