Recovery Operations Research Articles

TYPHOON DAMAGE MAPPING USING NORMALIZED DIFFERENCED SPATIAL AUTOCORRELATION AND PLANETSCOPE IMAGE

Abstract. Damages to built and natural environments are essentially changes that needs to be detected and quantified. This is particularly true for the change detection approach. While the use of vegetation indices is effective for such assessment in natural or vegetated areas, the use of built-up indices does not yield useful results. This is because there is usually no significant reduction in materials. However, typhoon-damaged buildings are usually characterized by a change in form, shape, color, and texture. In this study, we examined the use of local spatial autocorrelation (LSA) to evaluate the level of damage to buildings. In particular, the local Moran’s I was used, and an index called the normalized difference spatial autocorrelation (NDSA) was developed. Similar with other indices, the values are within the range of −1 to 1. NDSA using local Getis-Ord Gi and local Geary’s C were also generated. With the observation that LSA generally decreases due to damages (especially to manmade structures), positive NDSA identifies the damage areas. The magnitude of the values corresponded to the level or degree of damage sustained as interpreted from very high-resolution satellite image. It was noted that the manual tagging of damages had missed buildings which are clearly damaged or destroyed based on the visual comparison of pre- and post-typhoon satellite images. This illustrates the value of the NDSA not only to assess damage on its own but also for guiding manual tagging from image and prioritizing post-disaster needs assessment and recovery operation.

Buoyant oleophilic magnetic activated carbon nanoparticles for oil spill cleanup

In response to oil spills, it is imperative to develop efficient and eco-friendly sorbent materials. Oil remediation techniques are limited, prompting researchers to look into using nanotechnology for oil cleanup. Therefore, magnetic Fe3O4 composite nanoparticles (MNPs) were synthesized by the chemical co-precipitation method. The MNPs were then coated with activated carbon (AC) layer, followed by soybean oil/stearic acid surface decoration. The morphology and surface properties of the material were characterized using a scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), and contact angle (CA) analyses. The results showed an excellent amphiphilicity with water CA of 0° and oil CA of nearly 0°. In terms of applicability for oil recovery operations, the fabricated nanocomposite revealed sorption capacities greater than 6.5 g/g for a range of oils. In addition, the sorbent can be reused at least five times with advantageous characteristics for selective oil recovery on surface waters owning to its intense super-paramagnetic properties. Considering our results, we suggest that there is a practical application for magnetic AC nanomaterials in spilled oil response.

Statistical analysis of incidents on onshore CO2 pipelines based on PHMSA database

The development of an integrated network for the management of carbon dioxide requires knowledge and optimization of all Carbon Capture Utilization and Storage (CCUS) aspects, including pipeline transport. Safety is one of the aspects that should be addressed prior CCUS facilities come in operation; the risk for people should be assessed to ensure it is below an acceptable level. In some cases, a quantitative risk assessment (QRA) is required by the approval authority. Normally the risk assessment is based on the use of statistical/historical data. However, for CO2 handling systems the operating experience is limited compared to hydrocarbon transporting systems and, for this reason, hydrocarbon pipeline statistics are normally used as a proxy. The only database that contains records on CO2 pipelines is the PHMSA since in the U.S. several CO2 pipelines have been constructed since the 1970's, essentially for Enhanced Oil Recovery operations. There is limited statistical data available compared to the hydrocarbon pipelines experience and therefore care should be taken when undertaking the frequency analysis. In this work an analysis of incidents data related to the onshore CO2 pipelines in the U.S. between 1985 and 2021 reported by the Pipeline Hazardous Material Safety Administration (PHMSA) of the U.S. Department of Transportation is presented. The aim of the study is to analyze the records contained in the PHMSA database to provide an estimate of a specific CO2 pipeline failure rate to be used in quantitative risk assessments. Concerns and limitations of the data have been also discussed.

Reversible Data Hiding in Encrypted Domain Based on the Error-Correction Redundancy of Encryption Process

The existing reversible data hiding methods in encrypted domain separate image encryption from information embedding and do not make full use of the redundant space in the process of image encryption. In order to improve the performance of reversible data hiding by using the technical characteristics of image encryption, a reversible data hiding method based on McEliece error correction is proposed. Firstly, the segmentation position of bit plane is determined according to the embedding requirement and texture characteristic, and the image is divided into high and low significant bits. Secondly, because of the error-correcting characteristic of McEliece encryption, reversible data embedding can be realized while encrypting low significant bits. Then, the high significant bits are compressed to reserve space for the ciphertext extension of the low significant bits. Finally, the whole high significant bits information is stream-encrypted. As long as the image receiver has the decryption key, the image can be restored without distortion. By concealing the relationship between error correction and secret information mapping, the concealment of secret information transmission can be realized. In addition, due to different processing for different pixels, it can be efficiently transmitted with low computational complexity for applications that only need general images. The simulation results show that this scheme can not only realize the separable operation of information extraction and image recovery but also resist the noise attack to a certain extent. The maximum embedding rates of 10 standard images from USC-SIPI and 50 standard images from BOSS-BASE are 2.228 and 2.323 bpp, respectively.

Multicriteria analysis as a supporting decision tool for expanding the use of the 3T method for waste-to-energy technologies and biorefineries

The advancement of Circular Economy practices has accelerated the development of recovery operations in waste management. Moreover, novel Waste-to-Energy (WtE) plants go well beyond the conventional framework of Combined Heat and Power (CHP) production and have also focused on the recovery of metals or the secondary production of other products. Thus, an integrated methodology needs to be utilised for the holistic assessment of novel WtE plants. The previously introduced 3T Method is a thermodynamic approach that assesses not only the CHP efficiency but also the quality of the recovered materials/products. Nonetheless, this method operates optimally in net energy producing facilities. This study introduces an outranking multicriteria decision analysis (MCDA) method that incorporates the 3T method and can be used for the assessment of WtE plants that produce valuable materials (like gasification plants) and biorefineries. The thermodynamic parameters that are used in the 3T Method were integrated in a MCDA tool based on the PROMETHEE-GAIA methods and five WtE plants were analysed. The proposed tool successfully assessed the production of materials from Plant D with Phi flows of 0.4583 and 0.3682 for scenarios 1 & 2, while also evaluating positively the high CHP efficiency of Plant C with Phi flows of 0.0417 and 0.0864, respectively. Overall, the PROMETHEE-GAIA MCDA tool kept most of the positive attributes of the 3T Method, while enhancing at the same time the role of materials in the assessment process. This proposed tool can develop to be a useful method for assessment for biorefineries.

Experience in the surgical tactics of complex treatment of victims with severe combined trauma

Relevance. Currently, there is an increase in combined injuries worldwide, with more than a third of the victims of this category dying from various complications in the post-traumatic period.Objective: To determine the possibility of performing optimal surgical interventions in patients with multiple and combined trauma, including anti-shock, with shock of varying duration against the background of intensive therapy.Research material. The paper analyzes the surgical tactics of complex treatment of 150 victims with severe combined trauma. In the course of the study, we divided them into five clinical groups with various shock phenomena. Prediction and determination of the expected duration of shock against the background of intensive therapy was carried out using the table "Score assessment of shockogenicity of trauma" and nomograms developed at the I.I. Janelidze. Research Institute of Emergency Medicine.The results of the work. For clinical and prognostic groups, we noted a correlative relationship between the predicted duration of shock and the time of possible recovery operations, as a result, the coefficient of multiplicity of recovery was revealed. Dividing the average bed-day in hours by the duration of the shock in the forecast groups, we calculated the coefficient of multiplicity "K", which averaged 11 days. K= (144:12 + 184:18 +224:25) : 3 ≈ 11 ( days).Conclusions. Predicting the duration of shock allowed us to develop in an experiment and propose for implementation into clinical practice sparing surgical interventions that are of the nature of anti-shock, as well as to determine the most optimal time for performing reconstructive operations on the principle of simultaneous polysegmental osteosynthesis: 1. Operations for damage to the organs of the upper and lower floors of the abdominal cavity and pelvis. 2. Primary stabilization of fractures of the pelvic bones by an external fixation device in our modification. 3. Fixation of floating rib plastrons by the external fixation device of our modification. 4. Simultaneous polysegmental osteosynthesis.

Assessing flooding impact to riverine bridges: an integrated analysis

Abstract. Flood events are the most frequent cause of damage to infrastructure compared to any other natural hazard, and global changes (climate, socioeconomic, technological) are likely to increase this damage. Transportation infrastructure systems are responsible for moving people, goods and services, and ensuring connection within and among urban areas. A failed link in these systems can impact the community by threatening evacuation capability, recovery operations and the overall economy. Bridges are critical links in the wider urban system since they are associated with little redundancy and a high (re)construction cost. Riverine bridges are particularly prone to failure during flood events; in fact, the risks to bridges from high river flows and erosion have been recognized as crucial at global level. The interaction of flow, structure and network is complex, and not fully understood. This study aims to establish a rigorous, multiphysics modeling approach for the assessment of the hydrodynamic forces impacting inundated bridges, and the subsequent structural response, while understanding the consequences of such impact on the surrounding network. The objectives of this study are to model hydrodynamic forces as demand on the bridge structure, to advance a performance evaluation of the structure under the modeled loading, and to assess the overall impact at systemic level. The flood-prone city of Carlisle (UK) is used as a case study and a proof of concept. Implications of the hydrodynamic impact on the performance and functionality of the surrounding transport network are discussed. This research will help to fill the gap between current guidance for design and assessment of bridges within the overall transport system.

Towards circular manufacturing systems implementation: A complex adaptive systems perspective using modelling and simulation as a quantitative analysis tool

A transition towards circular manufacturing systems (CMS) has brought awareness of untapped economic and environmental benefits for the manufacturing industry. Conventional manufacturing systems already present a high level of complexity in terms of physical flows of materials and products as well as information and financial flows linked to them. Closing the loop of materials and products through multiple lifecycles, as proposed in CMS, increases this complexity manifold. To support practitioners in implementing CMS through enhanced decision-making, this research studies CMS from a complex adaptive systems (CAS) perspective and proposes to exploit methods and tools used in the study of CAS to characterise, model and analyse CMS. By viewing CMS as CAS composed of autonomous, interacting agents, this research proposes a multi-method model architecture for modelling and simulating CMS. The different CMS stakeholders are modelled individually as autonomous agents by integrating agent-based, discrete-event, and/or system dynamics modules within each agent to capture their diverse and heterogeneous nature. The applicability of the proposed multi-method approach is illustrated through a case study of a white goods manufacturing company implementing CMS in practice. This case study shows the relevance and feasibility of the proposed multi-method approach as a decision support tool for the systemic exploration and quantification of CMS. It also shows how a transition towards CMS necessitates a lifecycle approach in terms of costs, revenues and environmental impacts to identify hotspots and, therefore, design circular systems that are viable in both economic and environmental terms. In fact, the analyses of the simulation results indicate how decisions in terms of business models, product design, and supply chain might affect the CMS performance of the case company. For instance, implementing a service-based model led to a high number of usecycles (on average six usecycles per washing machine), which, in turn, led to high lifecycle costs and emissions due to more frequent transportation and recovery operations. Similarly, the deployment of long-lasting washing machines, which is a core principle of CMS, led to high manufacturing costs. Due to the high initial costs and a time mismatch between revenues and costs in the service-based model, it required a longer time for the company to reach the break-even point (approximately 23 months). Overall, the case study shows that multi-method simulation modelling can provide decision-making support for a successful implementation of CMS.

Hayabusa2 Re-Entry Capsule Tracking by Marine Radars

In the Hayabusa2 re-entry capsule recovery operation, marine radars were used to estimate the landing point of the capsule. These radars were commercial products for ships and were used with some modifications for this operation. The radars tracked the instrument module (I/M) containing the asteroid samples for 18 min, along with other equipment. The maximum observed distance was 31.55 km, and the tracking was accurate up to 240 m near the I/M landing point. This article describes the marine radar system, reports the tracking results of the operation, and discusses the considerations made for future missions. One consideration is to estimate the altitude by using multiple search radars in order to more accurately predict the landing point. Another is to estimate the radar cross-section of the I/M during descent. This article demonstrates that the altitude can be estimated by the search radars, and the radar cross-section fluctuates by approximately. 10 times depending on the elevation angle relative to the radar. The results of this article suggest the possibility of cooperative search by using multiple small radars. This feature may contribute to reductions in mission costs and to expanding the choice of landing areas.

Analysis on strategic and environmental issues of remanufacturing in India

Environmental awareness among masses has created tremendous pressure on government and corporates to preserve our natural resources. Globally, many companies have successfully initiated product recovery operations in their business plans. Remanufacturing is one of the highly profitable and sustainable product recovery options. Many Western countries successfully adopted remanufacturing as an alternate source of revenue generation model. But in India, it is still in nascent stage. In this research, we tried to identify the critical factors in the area of “Strategy & Environment” for the viability of remanufacturing business in India. For this, a questionnaire survey was conducted among Indian manufacturing companies and their responses were analyzed. The sample size of the study consists of 72 responses. Afterwards, the identified factors were ranked based on their criticality in initiating remanufacturing activity. The findings may help Indian government and manufacturing firms to frame proper strategy related to environmental aspect of remanufacturing operations in India.

A Study of Failure Recovery and Logging of High-Performance Parallel File Systems

Large-scale parallel file systems (PFSs) play an essential role in high-performance computing (HPC). However, despite their importance, their reliability is much less studied or understood compared with that of local storage systems or cloud storage systems. Recent failure incidents at real HPC centers have exposed the latent defects in PFS clusters as well as the urgent need for a systematic analysis. To address the challenge, we perform a study of the failure recovery and logging mechanisms of PFSs in this article. First, to trigger the failure recovery and logging operations of the target PFS, we introduce a black-box fault injection tool called PFault , which is transparent to PFSs and easy to deploy in practice. PFault emulates the failure state of individual storage nodes in the PFS based on a set of pre-defined fault models and enables examining the PFS behavior under fault systematically. Next, we apply PFault to study two widely used PFSs: Lustre and BeeGFS. Our analysis reveals the unique failure recovery and logging patterns of the target PFSs and identifies multiple cases where the PFSs are imperfect in terms of failure handling. For example, Lustre includes a recovery component called LFSCK to detect and fix PFS-level inconsistencies, but we find that LFSCK itself may hang or trigger kernel panics when scanning a corrupted Lustre. Even after the recovery attempt of LFSCK, the subsequent workloads applied to Lustre may still behave abnormally (e.g., hang or report I/O errors). Similar issues have also been observed in BeeGFS and its recovery component BeeGFS-FSCK. We analyze the root causes of the abnormal symptoms observed in depth, which has led to a new patch set to be merged into the coming Lustre release. In addition, we characterize the extensive logs generated in the experiments in detail and identify the unique patterns and limitations of PFSs in terms of failure logging. We hope this study and the resulting tool and dataset can facilitate follow-up research in the communities and help improve PFSs for reliable high-performance computing.

Separable Reversible Data Hiding in Encrypted VQ-Encoded Images

In this paper, a reversible data-hiding scheme in encrypted, vector quantization (VQ) encoded images is proposed. During image encryption, VQ-encoded image, including codebook and index table, is encrypted by content owner with stream-cipher and permutation to protect the privacy of image contents. As for additional-data embedding, a baseline method is first proposed and its corresponding optimized method is then given. By grouping one high-occurrence index with one or multiple low-occurrence indices, a series of index groups are constructed. Thus, by modifying the high-occurrence index to the corresponding index within the same group according to the current to-be-embedded bits, data embedding can be realized. The optimal hiding capacity is obtained by optimizing the coefficient vector for different types of index groups. Separable operations of data extraction, image decryption, and recovery can be achieved on the receiver side based on the availability of the encryption and data-hiding keys. Experimental results show that our scheme can achieve high hiding capacity and satisfactory directly decrypted image quality and guarantee security and reversibility simultaneously.

Potential of applying the thermochemical recuperation in combined cooling, heating and power generation: New concept and energy analysis

Employing combined cooling, heating and power (CCHP) production in the distributed energy network is a sustainable pathway to realize efficient energy conversion. In this work, the method of thermochemical recuperation (TCR) is introduced and integrated into the typical CCHP system, in order to further enhance the waste heat recovery and coordinate the system multiple energy output characteristics. Different from the direct thermal recovery, the high-temperature exhaust gas heat from the prime mover firstly drives the endothermic reactions, which is also readily stored in the chemical form and supports the subsequent CCHP production. The system thermodynamic performances are comprehensively investigated under various operation conditions. The results indicate that considerable irreversible loss during the chemical fuel utilization can be reduced, and the system power efficiencies are improved by 13.72–21.55% and 3.87%-17.16% for the gas turbine (GT) and the internal combustion engine (ICE) under the designated scenarios, respectively. Furthermore, diverse endothermic reactions are adopted to evaluate the practical application feasibility, and relatively stable and effective exhaust heat recuperation will be realized for the GT-based system off-design operation. Regarding to the ICE condition, the qualified exhaust waste heat will be completely recovered by the TCR process and then achieves the fuel saving ratio of 0.24%–14.64%, as well ensures the system operation stability and flexibility. Through the system evaluation, the method of TCR process provides an alternative way to enhance the efficient waste heat recovery and flexible operation for the CCHP production.

Many-Valued Logics and Bivalent Modalities

In this paper, we investigate the family LS0.5 of many-valued modal logics LS0.5's. We prove that the modalities of necessity and possibility of the logics LS0.5's capture well-defined bivalent concepts of logical validity and logical consistency. We also show that these modalities can be used as recovery operators.

A mathematical model for managing the multi-dimensional impacts of the COVID-19 pandemic in supply chain of a high-demand item.

The COVID-19 pandemic has wreaked havoc across supply chain (SC) operations worldwide. Specifically, decisions on the recovery planning are subject to multi-dimensional uncertainty stemming from singular and correlated disruptions in demand, supply, and production capacities. This is a new and understudied research area. In this study, we examine, SC recovery for high-demand items (e.g., hand sanitizer and face masks). We first developed a stochastic mathematical model to optimise recovery for a three-stage SC exposed to the multi-dimensional impacts of COVID-19 pandemic. This allows to generalize a novel problem setting with simultaneous demand, supply, and capacity uncertainty in a multi-stage SC recovery context. We then developed a chance-constrained programming approach and present in this article a new and enhanced multi-operator differential evolution variant-based solution approach to solve our model. With the optimisation, we sought to understand the impact of different recovery strategies on SC profitability as well as identify optimal recovery plans. Through extensive numerical experiments, we demonstrated capability towards efficiently solving both small- and large-scale SC recovery problems. We tested, evaluated, and analyzed different recovery strategies, scenarios, and problem scales to validate our approach. Ultimately, the study provides a useful tool to optimise reactive adaptation strategies related to how and when SC recovery operations should be deployed during a pandemic. This study contributes to literature through development of a unique problem setting with multi-dimensional uncertainty impacts for SC recovery, as well as an efficient solution approach for solution of both small- and large-scale SC recovery problems. Relevant decision-makers can use the findings of this research to select the most efficient SC recovery plan under pandemic conditions and to determine the timing of its deployment.

Controlling particle adhesion of synthetic and sewage sludge ashes in high temperature combustion using metal oxide nanoparticles

During combustion, ash particles can adhere to the internal walls of the plant due to partial melting and generate a liquid bridge force at the high operating temperatures. The adhered ashes inhibit energy recovery and stable operation of the plant. To achieve highly efficient energy recovery during combustion, it is necessary to investigate suitable methods to control adhesiveness according to each operational case. Herein, the ability of small amount (1–3 wt%) of nanoparticles (NPs: SiO2 NPs, Al2O3 NPs, and Fe3O4 NPs) as additives to control the adhesiveness at high temperatures was investigated. The controllability of each type of NP with respect to the adhesiveness of various synthetic ashes, which served as model compounds, was evaluated to clarify the role played by the different NPs. To demonstrate the practical utility of the NPs as additives, ash samples derived from the incineration of sewage sludge were investigated. Given the chemical complexity of the ash systems, it was discovered that a chemical effect and an increase in the porosity of the powder bed can effectively decrease the adhesiveness of ash particles produced at high temperatures.

Experimental evaluation of designed and synthesized Alkaline-Surfactant-polymer (ASP) for chemical flooding in carbonate reservoirs

More than half of the oil and gas resources of the world are hosted in carbonate reservoirs. Also, a total of 60% of their residual oil is left unswept during conventional primary and secondary oil recovery operations. The complexity of carbonate reservoirs due to relative weak water imbibition, undesired capillary forces, low permeability (less than 50mD), oil wetness and geochemical interactions in the presence of formation water high salinity causes precipitation of the injection chemicals resulting in clogging of pore throats and residual oil entrapment. Therefore, taking advantage of purposefully designed chemicals known as alkaline-surfactant-polymer (ASP) for enhanced oil recovery (EOR) applications rather than common commercial ASP materials for these challenging petroleum reservoirs is expected. In this research, the synthesized ASP combination was considered to improve the oil production mechanisms of the desired carbonate porous medium. Ultra-low interfacial tension about 1.6 × 10–3 has been achieved by Alkaline-Surfactant-Nano (ASN) synergistic formulation. Meanwhile, wettability alteration was evaluated by contact angle measurement. The contact angle was reduced from Θ = 155.2° (oil-wet) to Θ= 23.7° (water-wet) by the ASN combination. As well, the remarkable HTHS tolerable and shear resistance synthesized Co-polymer Nanocomposite was applied, and 10 times diluted seawater (losal) was chosen as chemicals compatible aqueous solvent for core flooding experiments. Thus, formulated ASP fluids were synergized by alumina nanoparticles at optimized concentrations of chemicals. Hence, this synthesized ASP is able to improve the residual oil production mechanism and lower the capillary pressure (Pc). 16 chemical flooding scenarios were run on Karanj oil field carbonate outcrop cores; the results of the four successful scenarios with the highest original oil in place (OOIP) recovery percentages are discussed. Experiments results are revealed that the cumulative oil recovery could arrive at 91% under the harsh condition of the reservoir. According to the findings of current research, this ASP formulation is highly recommended for chemical flooding of tight carbonate reservoirs.

Recovery Operation of Pop-up Type Ocean-Bottom Seismographs and Their Anchors from Continental Shelf to Upper Continental Slope

Recovery Operation of Pop-up Type Ocean-Bottom Seismographs and Their Anchors from Continental Shelf to Upper Continental Slope

Estimating the Shear Resistance of Flocculated Kaolin Aggregates: Effect of Flocculation Time, Flocculant Dose, and Water Quality.

The resistance of kaolin aggregates to shearing in water clarification and recovery operations is a critical input in designing thickener feed wells. A recently formulated but already available criterion is used to determine the shear strength of flocculated kaolin aggregates. The flocculant is a high molecular weight anionic polyelectrolyte. The resistance of the aggregates is evaluated as a function of flocculation time, flocculant dosage, and water quality. The determination is based on a standardized experimental method. First, the time evolution of the average size of kaolin flocs is measured when aggregates are exposed to incremental shear rates from a predetermined base value. Then, the results are fitted to a pseudo-first-order model that allows deriving a characteristic value of the shear rate of rupture associated with the upper limit of the strength of the aggregates. In seawater, at a given dose of flocculant, the strength of the aggregates increases with time up to a maximum; however, at longer times, the resistance decreases until it settles at a stable value corresponding to stable aggregates in size and structure. A higher flocculant dosage leads to stronger aggregates due to more bridges between particles and polymers, leading to a more intricate and resistant particle network. In industrial water with very low salt content, the resistance of the kaolin aggregates is higher than in seawater for the same dose of flocculant. The salt weakens the resistance of the aggregates and works against the efficiency of the flocculant. The study should be of practical interest to concentration plants that use seawater in their operations.

Pilot demonstration of nitrogen removal from municipal wastewater by vacuum membrane distillation

Nitrogen in municipal wastewater must be removed prior to discharge to the environment. However existing energy intensive aerobic processes used for nitrogen removal currently do not capture this important resource. Instead, nitrogen capture in the form of ammonia using a lower energy technology such as the membrane distillation; so far mostly tested in lab-scale, could be a significant improvement. This study reports a vacuum membrane distillation (VMD) pilot trial conducted at a municipal wastewater treatment plant to uniquely demonstrate ammonium removal and recovery to meet effluent discharge targets. The pilot plant was located in two streams on-site in the plant's anaerobic digester liquor handling facilities. The first trialed stream was on the existing phosphorus removal lime dosed effluent, and the second stream was effluent from an experimental struvite phosphorous recovery operation. In the post-lime scenario, VMD recovered N as ammonium sulphate solution and achieved up to 93% reduction. In the post struvite scenario, the VMD system achieved up to 85% reduction within the duration of the demonstration. With VMD driving force derived from volatility of the compound of interest, which is reliably calculated via Henry's law, the ammonia mass transfer coefficient across the membrane was 0.16 kg/m2/h/bar (±37% RSD) over the trial period, being lower than typical best case laboratory test results. Overall, the nitrogen removal and recovery process via VMD was proven technically viable on actual plant effluent leaving existing lime dosed and potential future struvite phosphorus removal systems. However, further studies are required to assess the economics of VMD for nitrogen removal compared with other nitrification-denitrification methods used in wastewater treatment.