Dsane, Victory Fiifi

Victory Fiifi Dsane works with Tomorrow Water, involved in advancing innovative approaches to water and wastewater treatment.

Titles from this speaker

A New Strategy to Control NOB in the Mainstream Anammox Process using Centrate from Anaerobic Digester

Abstract

Introduction Since its discovery in the 1980s, significant research continues to be conducted in Anammox process where, anaerobic ammonium-oxidizing bacteria utilize nitrite as an electron acceptor to oxidize ammonia to N2 gas, with about 10% of nitrogen being converted to nitrate (1). While nitrite is essential for anammox, nitrogen in wastewater primarily exists in the form of ammonium, thus ammonia-oxidizing bacteria (AOB) are employed to initially oxidize a portion of the ammonia to nitrite. Nitrite-oxidizing bacteria (NOB) however, compete with AOBs by oxidize nitrite rapidly to nitrate and hinder the anammox process. In side-stream treatment, effective NOB suppression is possible due to elevated influent temperature, pH, and NH4 concentration. These merits however do not exist in mainstream. To overcome these limitations and achieve stable partial nitritation (PN), various methods to suppress NOB have been employed (2; 3). The goal of this research is to improve the performance of PN in the mainstream process with an innovative and repeatable strategy to control growth of NOB, by employing available resource at a treatment facility with minimal process disruption and using supernatant from an anaerobic digester (AD) presents the best solution for this. AD supernatant offers the advantages of; warm temperature and environment to instantaneously inhibit NOB as well as alkalinity to buffer pH changes. Method A lab-scale reactor was operated for 2 years to derive basic and optimized operational parameter Based on these results; a pilot plant was operated at the city of LA's Hyperion WWTP for 8 months. Lab-scale (Proof of concept): Three different media types with diverse surface areas (M-1, M-2, M-3) were used in the lab-scale reactors. The innovative NOB control protocol involved a 100% fill and decant cycle (fig 1.1a), DO/NH4 ratio target was maintained as 0.2. Instant introduction or AD supernatant when effluent nitrate concentrations consistently exceeded 5mg/L. Monitoring of free ammonia (FA) and free nitrous acid (FNA) was done to help stimulate the growth and performance of AOBs. Pilot Scale: Based on the optimized results from lab-scale operation, a 1.3 m3 pilot plant operation (fig 1.1b) was carried out in a similar manner using M-2 (highest PN performance media) and the secondary effluent of the Hyperion WWTP as the influent, with an average concentration of 50+/-3.5 mgNH4-N/L for about 250 days. Two (2) different supernatant exposure methods were tested in the pilot based on pH control. Results Fig 1.2 shows the effluent nitrogen concentrations over the operational period. The 100% fill and decant cycle strategy significantly helped in shortening the start-up phase relative to other mainstream processes (2). To optimize the PN performance and economically control NOBs, two different inhibition methods (mainly based on initial supernatant pH control) were adopted to monitor the time required between each inhibition reaction before effluent NO3-N exceeded the set mark of 5mg/L, at which point optimal PN is hindered. It was identified that employing exposure method I (no initial pH control) took fewer days and enhanced the inhibitory potential of NOB and help maintain effluent NO3-N levels below 5mg/L for longer periods relative to exposure method II. Supernatant exposure method II involved controlling initial pH of supernatant to 8.5 by dosing with phosphoric acid and this pH level maintained for first 10 hrs prior to an inhibition reaction. Since pH and temperature determine the reactors instantaneous FA and FNA concentrations, these were monitored for the two distinct exposure methods. Fig. 1.3 shows drastic reduction in NH4 and FA in the exposure method I. Thus, for mainstream PN processes at plants where AD is available, direct application of the AD supernatant without pH control in a regular and recurrent manner can successfully inhibit NOB while improving the performance of AOB in treating higher N-loads. To confirm the effectiveness of the inhibition reaction with AD supernatant a validation of AOB performance and a corresponding effective NOB inhibition was carried out for 20 hrs using NH4-N and NO2-N as the batch experiment substrate, respectively (Fig. 1.4). The minimal nitratation (fig. 1.4b) that occurred at relatively low NO2-N substrate levels confirms the successful inhibition and absence of NOBs after employing the innovative supernatant exposure inhibition reaction. Summary and Recommendation This research successfully achieved a stable mainstream PN operation at high N loading rate both in the lab-scale and pilot scale by employing a reliable, economical, and repeatable NOB inhibitory method, using AD supernatant. By implementing a 100% fill and decant sequence, relying on elevated AD supernatant temperatures, regular inhibition reaction could be carried out when effluent NO3-N recurrently exceeds 5 mg/L. This new strategy utilizes available plant resources, thereby reducing cost of employing alternative NOB inhibitory techniques. However, other control measures must be selected at those plants that do not have digesters. The next phase of this research involves direct application in the full-scale plant, identification of inhibitory sequence for a smooth operation in a full-scale plant as well as investigation of alternative environmentally friendly control measures for plants without ADs.

This study explores achieving stable partial nitritation (PN) in the mainstream process using anaerobic digester centrate. Starting from a lab-scale reactor to a pilot scale at Hyperion Water Reclamation Plant, it presents a strategy to control nitrite-oxidizing bacteria (NOB) by leveraging warm temperatures, instant NOB inhibition, and alkalinity buffer. The unique operational strategy favored ammonia-oxidizing bacteria (AOB) and achieved a nitrogen loading rate of 2.2 kg-N/m3/d.

SpeakerDsane, Victory Fiifi

Presentation time

13:30:00

13:40:00

Session time

13:30:00

15:00:00

SessionInnovations in Partial-Nitritation-Anammox Processes

Session number607

Session locationRoom 344

TopicIntermediate Level, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Dsane, Victory Fiifi, Rhu, Daehwan, Dsane, Victory Fiifi, Ghimire, Umesh, Kang, Shin Joh, Liberzon, Jon, Saneie, Shahrouzeh, Samar, Parviz, Sathyamoorthy, Sandeep

Author(s)V.F. Dsane1, D. Rhu2, U. Ghimire3, S.J. Kang4, P. Samar5, S. Saneie5, S. Sathyamoorthy6

Author affiliation(s)1TOMORROW WATER, CA, 2Tomorrowwater, CA, 3, MS, 4Water & Energy Advisors LLC, MI, 5City of Los Angeles, CA, 6, CA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159628

Volume / Issue

Content sourceWEFTEC

Word count17

Achieving Stable Performance by the Co-digestion of Livestock Manure and Food Waste in an Anaerobic Sequencing Batch Reactor (AnSBR)

Abstract

Introduction Anaerobic digestion (AD) can be briefly described as a series of processes involving microorganisms degrading organic matter in the absence of oxygen with final by-products of methane, carbon dioxide, hydrogen sulfide, ammonia, and new biomass (Veeken et al., 2000; Kelleher et al., 2002). Although AD is one of the most cost-effective technologies due to the plausible high energy and resource recovery from organic matters (Ding et al., 2017), there are challenges and the need for innovative methods to tap into the total resource recovery and utilization of the wastewater treatment process. In the AD process, various types of microorganisms sequentially degrade organic matters in multi-steps and parallel reaction. The AD process of complex organic matters generally involves three interrelated steps: hydrolysis, fermentation (acidogenesis and acetogenesis) and methanogenesis by methane producing bacteria (MPB). The major challenges of AD are, therefore, the slow hydrolysis rate; where unhydrolyzed organic matter is discharged and directly impact the growth of MPB thereby lowering the methanogenic rate. An innovative approach was tested and applied in this study; including, increasing the solid retention time (SRT) using an anaerobic sequencing batch reactor (AnSBR); a patented highly effective mixers and a new settled sludge discharge system at the bottom of the reactor. An enhanced performance and stability of the AAD is achieved in the evaluation of a full-scale (100 ton/d) plant in Korea. Methods The full-scale Advanced Anaerobic Digestion (AAD) process was operated at the Miryang livestock treatment plant in Korea for 300 days, processing 80 m3/d of livestock manure and about 18~39 m3/d of food waste (household, restaurant). The AAD was operated with the AnSBR with 8 hours cycle mode (thus, 80 mins filling — 280 mins reaction — 100 mins settling — 20 mins decanting). The AAD distinguishes from the conventional AD in that, the SRT is significantly increased to improve biogas production, and the HRT on the other hand shortened. The patented novel discharging system at bottom of digesters allows removal of settled non-biodegradable sludge (sands and others) without affecting the operation of the AD and with the high-performance agitators (Fig. 1.1), settled biodegradable solids quickly mixed with other solids in each cycle. The scum layers are not formed in this system and this new design thus utilizes the full digester volume without non-usable volumes found in conventional digesters for scum layer and accumulated non-biodegradable solids settled at the bottom. Table 1.1 summarizes the operational parameters of the AAD. Results Process performance: Over the operational period, influent volatile solids (VS) concentration fluctuated averaging 30,091.9 +/- 5,788.8 (16,381.6-43,373.9) mg/L. This fluctuation of influent VS was mainly due to the change of food waste input leading to changes of the OLR. Effluent VS concentration however remained stable and average VS removal rate was 70.6+/-3.1 (Fig. 1.2). In Fig. 1.3, the fluctuating biogas and methane production resulting from varying influent VS is shown. However, the AAD's unique operational procedures allowed for a stable methane content and the performance yield. (Fig. 3 (b) and (c)). In the conventional AD process, while higher OLR improve the processing efficiency by dropping operational pH, it causes accumulation of volatile fatty acids (VFAs) and excessive production of carbon dioxide, this inhibits the MPB and in effect accelerate the process failure. On the other hand, lower OLR generally decline efficiency. Thus, the AAD process uniquely withstands these highs and lows in OLR with its SBR operational procedures. Process stability: Process stability was attained early in the first 60 days of operation of the full-scale AAD. The AnSBR retains high biomass level due to bioflocculation followed by biogranulation. The advantages of employing AnSBR including biomass flocculation, solids separation, high SRT etc. hastened the stability of the AAD process at Miryang. The AAD's innovative discharge system equipped at the bottom of the digester for the discharge of non-biodegradable matters (usually heavier and settle faster during the setting period), such as fixed solids (FS) that accumulate at the bottom of the digester also enhanced stability. The communicative nature of the radar level sensor (installed at the top), pressure level sensor (install at the bottom) and discharge system improve the overall process efficiency and maintains a uniform water level pressure on the sensors. (Table 1.2 and Fig. 1.3). Khanal, 2008, emphasized the essence of maintaining a uniform temperature during settling in digesters due to the sensitive nature of MPB to temperature. Table 1.3 shows the temperature changes observed at the top, mid and bottom of digester during settling. Although total solids (TS) concentration at the top of digester dropped to 1.58% from 2.46%, there were no significant changes in temperature along the different digester levels over the settling period a good indication of the AAD stable performance. Conclusion This study evaluated the stability and performance of a full-scale AAD process with AnSBR to produce biogas using livestock manure and domestic food wastes. The advantages of employing an AnSBR with patented mixing system and settled non-biodegradable sludge discharge system, was seen in the stable perfo

This study examines the performance and stability of a full-scale anaerobic sequencing batch reactor (AnSBR) at Miryang, South Korea. This new co-digestion approach is dubbed advanced anaerobic digester (AAD) process. The AAD, equipped with movable agitators and radar sensor control, demonstrated good performance at higher organic loading rates (OLR). The technology showed advantages over conventional anaerobic digesters for handling waste.

SpeakerDsane, Victory Fiifi

Presentation time

15:30:00

16:00:00

Session time

15:30:00

17:00:00

SessionWater Recovery in Livestock Production

Session number424

Session locationRoom 235

TopicAdvanced Level, Biosolids and Residuals, Industrial Issues and Treatment Technologies, Water Reuse and Reclamation

Author(s)

Dsane, Victory Fiifi, Choi, Jaemin, Rhu, Daehwan, Dsane, Victory Fiifi, Kang, Shin Joh, Choi, Yongju, Jung, Minki

Author(s)V.F. Dsane1, J. Choi2, D. Rhu3, S.J. Kang4, Y. Choi5, M. Jung2

Author affiliation(s)1Tomorrow Water2BKT Co. Ltd, 3Tomorrowwater 4Water & Energy Advisors LLC, MI, 5Soeul National University

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159670

Volume / Issue

Content sourceWEFTEC

Word count20

Integrating Fixed-Film Biofiltration into Primary Treatment Processes

Abstract

As wastewater treatment facilities face increasing constraints on footprint, energy consumption, and capital expansion, there is growing interest in treatment technologies that intensify performance within existing process boundaries. Conventional primary clarification is largely limited to gravity-driven particulate solids removal and provides minimal attenuation of soluble organic matter, thereby placing the full burden of biological oxidation on downstream secondary treatment processes. This conventional separation of physical and biological treatment functions results in large reactor volumes, high aeration demand, and limited operational flexibility. This study evaluates an integrated primary biofiltration approach that introduces fixed-film biological activity into a primary treatment configuration, effectively redefining primary treatment as an intensified, multifunctional unit process capable of combining physical filtration and biological oxidation. An up-flow floating media biofiltration pilot system was designed and operated over a seven-month period (August 2024-March 2025) at the Linda County Water District municipal wastewater treatment plant in Northern California. The reactor consisted of two vertically stacked floating media zones: a lower, unaerated filtration zone providing physical capture of suspended solids, and an upper, aerated zone supporting attached biofilm growth and biological oxidation. This configuration enabled concurrent solids removal and biological treatment within a single vessel, while maintaining short hydraulic retention times compatible with primary treatment applications. Pilot testing was conducted at empty bed contact times (EBCTs) of 20, 30, 60, and 120 minutes to evaluate system performance across a range of hydraulic and organic loading conditions representative of both high-rate and extended-contact operation. Treatment performance was assessed using total suspended solids (TSS), five-day biochemical oxygen demand (BOD), and soluble chemical oxygen demand (sCOD) as key indicators of physical and biological treatment efficacy. Results demonstrate that integrating fixed-film biological activity into a primary treatment configuration can substantially intensify organic removal at hydraulic retention times far shorter than those required for conventional secondary treatment. At EBCTs of 20-30 minutes, the system consistently achieved TSS removals on the order of 80%, exceeding values typically reported for conventional primary clarification, while simultaneously achieving measurable reductions in soluble organics (50-59% sCOD removal). These results indicate that the system provided meaningful attenuation of both particulate and soluble organic loading under short-contact conditions relevant to high-rate treatment. At an EBCT of 60 minutes, average BOD removal exceeded 80% and sCOD removal exceeded 70%, demonstrating that a significant fraction of biological oxidation typically assigned to secondary treatment could be achieved upstream within a compact primary-scale reactor. Analysis of effluent sCOD:BOD ratios revealed a progressive shift toward more stabilized organic fractions with increasing EBCT, confirming that soluble organic removal was driven by biological oxidation within the attached biofilm rather than physical filtration alone. Importantly, solids removal performance remained stable across all tested EBCTs, indicating that biological activity did not compromise filtration performance and that the integrated system was resilient to hydraulic variability. These findings suggest that the combined physical-biological configuration can decouple solids capture from biological kinetics while maintaining consistent treatment performance. High oxygen transfer performance was observed within the aerated biofiltration zone, sustaining biofilm growth and enabling biological oxidation at elevated areal and volumetric rates. Measured oxygen transfer efficiencies per unit depth ranged from 1.10 to 1.69% OTE·ft⁻¹ exceeding values commonly reported for conventional activated sludge systems, including those equipped with fine-pore diffusers. These elevated oxygen transfer efficiencies are notable given the relatively shallow reactor depth and primary-scale configuration, and they suggest favorable gas-liquid mass transfer conditions associated with the floating media architecture and internal hydraulics. At extended EBCTs, partial nitrification was observed, further confirming the biological functionality of the integrated system and indicating that the reactor environment supported both heterotrophic and autotrophic microbial activity. Similar performance trends were independently documented at a separate facility in Ohio in 2025, supporting the broader applicability of the observed mechanisms. Collectively, these results demonstrate that biologically active primary biofiltration can shift a meaningful portion of organic oxidation upstream of secondary treatment, thereby reducing the biological load imposed on downstream processes. From a treatment-train perspective, this redistribution of treatment functions has implications for secondary reactor sizing, aeration demand, and solids production dynamics. By consolidating physical filtration and biological oxidation within a single intensified unit process, integrated primary biofiltration offers a pathway toward more compact, energy-efficient, and adaptable wastewater treatment configurations. This work reframes primary treatment not as a passive, gravity-driven step, but as an active and biologically relevant process with the potential to simplify treatment trains and enhance overall system performance.

This paper was presented at the WEF Residuals, Biosolids, and Treatment Technology Conference in Kansas City, MO, May 11-14, 2026.

Presentation time

08:30:00

09:00:00

Session time

08:30:00

10:00:00

SessionUnderstanding a Variety of Biofilm Applications

Session locationKansas City Convention Center

TopicInnovative and Advanced Treatment for Achieving Limit-of-Technology Performance

Author(s)

Dsane, Victory Fiifi, Rhu, Daehwan, Kang, Shin Joh, Dursun, Derya, Caliskaner, Onder, Daigger, Glen, Wu, Yuanbin

Author(s)V. Dsane1, D. Rhu1, S. Kang, D. Dursun2, O. Caliskaner2, G. Daigger3, Y. Wu2

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date May 2026

DOI10.2175/193864718825160224

Volume / Issue

Content sourceResiduals, Biosolids and Treatment Technology Conference

Word count8

Resilience in Action: Withstanding High-strength Sulfate Containing Wastewater, The Case of Korea's First Full-scale PN-Anammox

Abstract

Introduction Partial-Nitritation/Anammox (PN/A) processes are increasingly being selected as energy and carbon positive options in the treatment of ammonium-rich side-streams from digestate. Two-stage, sequential PN/A systems were the first to be developed and subsequently, single-stage PN/A (where PN and Anammox reactions occur simultaneously in a single reactor) processes were developed. Although the later possesses the advantage of footprint reduction, these processes have lower HRT and require a balance in aeration and loading such that DO concentrations remain high enough to drive nitritation, but low enough to avoid inhibiting Anammox metabolism, which proves to be a persistent challenge. In general, the highly sensitive nature of the anammox process requires that all plausible inhibiting factors (such as heavy metals, sulfate, etc.) are curbed within practical thresholds. A Two-stage PN/A (AMX(R)) process recently reported by Jung et al. (2019) reduces the HRT required in dedicated PN reactors and improves the system's resilience to high ammonium, COD and solids loads. This technology was therefore employed for the reject water treatment within B City's N-treatment plant in Korea, making it the first and only full-scale domestic application in Korea. This paper discusses the resilience of this AMX technology and adopted strategies in overcoming unforeseen high levels of Sulfate (SO42-) in the influent streams. High sulfate concentrations inhibit anammox and reduces nitrogen removal efficiency (E. Rikmann et al., 2016). Therefore, the exact effects of high strength sulfate on a full-scale PN/A process and the resulting steps to long-term operation to stabilize nitrogen removal efficiency in a practical, economical, and innovative way is presented in this work. Methods Fig. 1.1 shows the industrial treatment processes at B City's N-WWTP with a capacity of 184,000 m3·d-1. A combined 778 m3·d<sup?-1 of concentrated sludge and food waste sludge are introduced into the anaerobic digester. After approximately 30 days in the digester, the sludge is further dewatered into 123 m3·d-1 of sludge cake. Meanwhile, the 817 m3·d-1 of filtrate from the dewatering process, is channelled to the Two-stage AMX(R) (Fig. 1.2) process, which is tailored for treating digester effluents with elevated nitrogen levels. Highest measured sulfate levels exceeded the reported anammox threshold by 90%. Results and Discussion The operation for the full scale PN/A process was segmented into three distinct phases: seeding and SO42- control, continuous nitrogen load increase, and performance validation phase. In Table 1.1, the summarized key operating factors and performance results for each phase is tabulated. In Phase I, the unforeseen high sulfate concentration wastewater (Fig. 1.3) fed into the Two-stage AMX(R) process prevented a quick start-up and acclimation of the anammox. According to S. Zhou et al, 2022, in the absence of sulfate reducing ammonium oxidizing bacteria (sulfammox), sulfate levels exceeding 100 mg/L can instantly inhibit any species of anammox bacteria. Therefore, to prevent complete microbial activity loss and intuitively introduce additional biomass, the energy currency of all living cells, ATP was quickly monitored alongside the specific anammox activity (SAA). By measuring SAA, intermittent biomass was gradually added in a timely and economically manner to prevent further SO42- shock and activity loss. SO42- control was simultaneously carried out. Consequently, the anammox reactor HRT was extended beyond its design, while the NLR dipped far below its design value of 0.87 kgN·m-3·d-1. By phase II, as the sulfate concentration in the influent was controlled and kept below 300 mg·L-1, the nitrogen load in the Anammox reactor was gradually increased. HRT was shortened to 2.1 days (design HRT: 1.5 days). This led to an average NLR of 0.57 kgN·m-3·d-1, with a nitrogen removal efficiency of 81%. In Phase III, the NLR reached its design value of 0.87 kgN·m-3·d-1, and performance was evaluated over roughly a month. The operating HRT and average NLR during this phase stood at 1.5 days and 0.89 kgN·m-3·d-1, respectively. The nitrogen removal efficiency averaged 84.6%, surpassing the operational goal of 82%.By analyzing the data of the existing S-WWTP and K-WWTP, provided by B-City, the N-WWTP was identified to have reduced operating costs by 83%, capital expenditures by 64- 93%, and process footprint by 70-90% by applying the Two-stage AMX(R) technology, compared with conventional technologies. In monetary terms, energy costs were reduced by 60%, chemical costs by 99%, and sludge treatment costs by 49%, saving more than KRW 1.5 billion ($1.15M) per year in OPEX. Construction costs were reduced by KRW 1 billion to up to KRW 7.5 billion ($5.73M). Conclusion This paper summarized the effects of high strength sulfate on the full-scale anammox process and the resulting long-term stable nitrogen removal efficiency by simultaneously counteracting the sulfate and phasing the nitrogen loads in a pragmatic but intuitive and repeatable manner. By employing innovative techniques like direct ferric addition and microbial specific activity monitoring at specific intervals, anammox reseeding was done to prevent complete activity loss in a unique but economical fashion. The resilient AMX technology achieved the designed NLR of 0.87 kgN·m-3·d-1 and exceeded the nitrogen removal performance target of 82% reducing nitrogen loads.

This study addresses the challenges of treating industrial wastewater with anammox, focusing on the first full-scale implementation in Korea. Elevated sulfate levels required innovative solutions for the two-stage PN/A process. Key variables were identified and controlled, demonstrating the process' resilience. Compared to conventional methods, this technology reduced operating costs by 83%, capital expenditures by 64-93%, and process footprint by 70-90%, offering significant economic benefits.

SpeakerDsane, Victory Fiifi

Presentation time

13:50:00

14:00:00

Session time

13:30:00

15:00:00

SessionInnovations in Partial-Nitritation-Anammox Processes

Session number607

Session locationRoom 344

TopicIntermediate Level, Municipal Wastewater Treatment Design, Nutrients, Research and Innovation

Author(s)

Dsane, Victory Fiifi, Oh, Taeseok, Choi, Yunkyu, Choi, Younggyun, Dsane, Victory Fiifi, Jung, Minki, Kang, Shin Joh, Kim, Jeongmin, Okabe, Satoshi, Rhu, Daehwan

Author(s)V.F. Dsane1, T. Oh1, Y. Choi2 M. Jung2, S.J. Kang3, J. Kim2, S. Okabe4, D. Rhu5

Author affiliation(s)1TOMORROW WATER, CA, 1, 2BKT Co. Ltd, 2, 3Water & Energy Advisors LLC, MI, 4Hokkaido University, Sapporo, Japan, 5Tomorrowwater, CA

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2024

DOI10.2175/193864718825159665

Volume / Issue

Content sourceWEFTEC

Word count16

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Dsane, Victory Fiifi

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