John T. Novak

Virginia Polytechnic Institute and State University, Блэксбург, Virginia, United States

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Publications (161)233.82 Total impact

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    Syeed Md Iskander · Brian Brazil · John T. Novak · Zhen He
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    ABSTRACT: Landfill leachate has recently been investigated as a substrate for bioelectrochemical systems (BES) for electricity generation. While BES treatment of leachate is effective, the unique feature of bioelectricity generation in BES creates opportunities for resource recovery from leachate. The organic compounds in leachate can be directly converted to electrical energy through microbial interaction with solid electron acceptors/donors. Nutrient such as ammonia can be recovered via ammonium migration driven by electricity generation and ammonium conversion to ammonia in a high-pH condition that is a result of cathode reduction reaction. Metals in leachate may also be recovered, but the recovery is affected by their concentrations and values. Through integrating membrane process, especially forward osmosis, BES can recover high-quality water from leachate for applications in landscaping, agricultural irrigation or direct discharge. This review paper discusses the opportunities, challenges, and perspectives of resource recovery from landfill leachate by using BES.
    Full-text · Article · Nov 2015 · Bioresource Technology
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    ABSTRACT: This study evaluates the biological solid reduction in a conventional activated sludge system with an anoxic/anaerobic side stream reactor receiving 1/10 of return sludge mass. Influent iron concentrations and feeding modes were changed to explore the consistency between the influent iron concentration and yield values and to assess the impact of feeding pattern. The results indicated that sludge reduction occurs during alternately exposure of sludge to aerobic and anoxic/anaerobic conditions in a range of 38-87%. The sludge reduction values reached a maximum level with the higher iron concentrations. Thus, it is concluded that this configuration is more applicable for plants receiving high iron concentrations in the wastewaters. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · Oct 2015 · Bioresource Technology
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    Mohan Qin · Hannah Molitor · Brian Brazil · John T Novak · Zhen He
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    ABSTRACT: A microbial electrolysis cell (MEC)-forward osmosis (FO) system was previously reported for recovering ammonium and water from synthetic solutions, and here it has been advanced with treating landfill leachate. In the MEC, 65.7±9.1% of ammonium could be recovered in the presence of cathode aeration. Without aeration, the MEC could remove 54.1±10.9% of ammonium from the leachate, but little ammonia was recovered. With 2M NH4HCO3 as the draw solution, the FO process achieved 51% water recovery from the MEC anode effluent in 3.5-h operation, higher than that from the raw leachate. The recovered ammonia was used as a draw solute in the FO for successful water recovery from the treated leachate. Despite the challenges with treating returning solution from the FO, this MEC-FO system has demonstrated the potential for resource recovery from wastes, and provide a new solution for sustainable leachate management.
    Full-text · Article · Oct 2015 · Bioresource Technology
  • Abhinav Gupta · John T. Novak · Renzun Zhao
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    ABSTRACT: Disposal and treatment of the return liquor produced by the dewatering of the thermal hydrolysis pretreated anaerobic digestion biosolids is a major concern for treatment plants because the presence of UV quenching substances in the return liquor might interfere with UV disinfection. Also, with the lowering of effluent nitrogen standards in some locations, development of treatment techniques for nitrogen-containing organics in the return liquor is required. In this study, the molecular weight (MW) and chemical nature based fractions were characterized by their total organic carbon, UV absorbance, organic nitrogen and protein content. The humic acids and the hydrophilic fraction were found to be the major contributors to the organic matter and organic nitrogen in the return liquor, whereas the humic substances (humic and fulvic acids) were found to be mainly responsible for the UV254 quenching. Humic substances were observed to be the larger molecular weight (mainly >1 kDa) fractions and could not be efficiently removed by aerobic biological treatment.
    No preview · Article · Aug 2015 · Journal of Environmental Chemical Engineering
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    ABSTRACT: Landfill leachates are often discharged through sewers or by trucks to publicly owned treatment works (POTWs) after on-site biological treatment. This discharge of landfill leachate is widely accepted because of its cost-effectiveness and reliability, but potential impacts of this practice include additional nutrient loading and interference with ultraviolet (UV) disinfection during subsequent biological treatment. Leachate was fractionated into humic acid (HA), fulvic acid (FA), and hydrophilic (Hpi) fractions based on chemical composition and solubility to determine the hydrophobicity distribution. The analysis showed that the specific UV254 absorbance (SUVA254) of the humic substances (HA and FA) was significantly higher than the Hpi fraction. The UV quenching materials were found to be resistant to biological treatment for the majority of leachates studied. Removal of humic substances was associated with decreased UV quenching and the aromatic content of landfill leachates after biological treatment. The size distribution of the hydrophilic fraction suggests that the majority of organic nitrogen in landfill leachate is associated with the low-molecular-weight (<1∈∈kDa) hydrophilic fraction.
    No preview · Article · Apr 2015 · Journal of Environmental Engineering
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    John T. Novak · Chang Min Park

    Full-text · Article · Feb 2015
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    ABSTRACT: This study investigates the effect of landfill age on landfill leachate characteristics; two aspects are focused here. One is ultraviolet absorbance at 254 nm (UV254) property, as the discharge of landfill leachates to publically owned treatment works can cause interference with UV254 disinfection. The other is biorefractory organic nitrogen in leachates, as it can contribute to effluent nitrogen making it difficult to meet stringent effluent nitrogen regulations. To study variation in UV254-absorbing organic carbon and organic nitrogen, leachate samples ranging from cells with ages 2 to 30 y from a large landfill in Kentucky, were collected and fractionated on a basis of their molecular weight and chemical nature into humic acids, fulvic acids and a hydrophilic fraction. The effectiveness of long term landfilling and membrane treatment for organic matter and organic nitrogen removal was examined. Humic materials, which were the major UV254-absorbing substances, were mainly >1 kDa and they degraded significantly with landfill age. The hydrophilic organic fraction, which was the major contributor to organic nitrogen, was mainly <1 kDa and it became increasingly recalcitrant with landfill age. This study provides insight into the characteristics of the different leachate fractions with landfilling age that might aid the design of on-site leachate treatment techniques.
    No preview · Article · Sep 2014 · Waste Management & Research
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    ABSTRACT: Unlabelled: Prior research suggests that cold temperatures may stimulate the proliferation of certain antibiotic resistance genes (ARGs) and gene transfer elements during storage of biosolids. This could have important implications on cold weather storage of biosolids, as often required in northern climates until a time suitable for land application. In this study, levels of an integron-associated gene (intI1) and an ARG (sul1) were monitored in biosolids subject to storage at 4, 10 and 20°C. Both intI1 and sul1 were observed to increase during short-term storage (<2 months), but the concentrations returned to background within 4 months. The increases in concentration were more pronounced at lower temperatures than ambient temperatures. Overall, the results suggest that cold stress may induce horizontal gene transfer of integron-associated ARGs and that biosolids storage conditions should be considered prior to land application. Significance and impact of the study: Wastewater treatment plants have been identified as the hot spots for the proliferation and dissemination of antibiotic resistance genes (ARGs) and antibiotic resistant bacteria (ARB) to the environment through discharge of treated effluent to water bodies as well as application of biosolids to land. Identifying critical control points within the treatment process may aid in the development of solutions for the reduction of ARGs and ARB and curbing the spread of antibiotic resistance. This study found increases in ARGs during biosolids storage and identifies changes in operational protocols that could help reduce ARG loading to the environment when biosolids are land-applied.
    No preview · Article · Sep 2014 · Letters in Applied Microbiology
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    ABSTRACT: To manage water quality in the Occoquan Reservoir, Virginia, a water reclamation facility discharges nitrified product water that reduces the release of undesirable substances (e.g., phosphorus, iron, and ammonia) from sediments during periods of hypolimnetic anoxia. Results showed that when the oxidized nitrogen (OxN) concentration input to the reservoir was lower than 5 mg N/L during periods of anoxia following thermal stratification, nitrate was depleted in the upper reaches of the reservoir resulting in the release of ammonia and orthophosphate from the sediments downstream. When the OxN input to the reservoir was operationally increased to a concentration greater than 10 mg-N/L, orthophosphate release was suppressed. Introducing OxN to the system decreased sediment ammonia release but did not eliminate it. By discharging reclaimed water that contained nitrate levels greater than 10 mg N/L, reservoir water quality was protected and the discharged nitrate was converted to nitrogen gas as it moved downstream.
    No preview · Article · Feb 2014 · Water Environment Research
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    ABSTRACT: When landfill leachate, with or without biological pretreatment, is discharged to publically owned treatment works (POTWs), it can interfere with the installed treatment facilities. Biological treatment is ineffective for the removal of some of the bio-refractory organic matter, including UV254 quenching substances. Fenton's reagent treatment for biologically treated landfill leachates is examined in this study as a polishing step to make landfill leachates acceptable to POTWs. The optimum conditions for the Fenton's reagent treatment are explored. The molecular weight and hydrophobic-hydrophilic nature based fractions of the Fenton's treated leachate samples are analyzed to provide insight into the leachate fractions targeted by the Fenton's reagent. The results indicate that Fenton's reagent can act as a good compliment to biological treatment as it can remove leachate fractions which are widely considered to be bio-refractory. It exhibited good UV254 absorbance removal by removing larger molecular weight humic substances and thus, can help solve the UV254 quenching problem due to leachates discharged to POTWs.
    No preview · Article · Jan 2014 · Chemosphere
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    Chang Min Park · John T Novak
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    ABSTRACT: The role of iron addition to sewage sludge prior to anaerobic digestion was evaluated to determine the effect of iron on digestion performance and generation of odor-causing compounds. Hydrogen sulfide (H2S) and volatile organic sulfur compounds (VOSCs) were the odorous gases evaluated in this study. Samples were obtained from seven municipal wastewater treatment plants (WWTPs), and batch anaerobic digestion tests were conducted using primary and secondary sludges at 30 day solids retention time (SRT) under mesophilic conditions. Volatile solid removal (VSR) was highly predictable with background iron concentrations measured in the combined sludge. They were likely to increase as influent iron content increased. 1.25% w/w ferric chloride (FeCl3) was added to the anaerobic digester feed in order to simulate iron addition for sulfide control in full-scale WWTPs. The results showed that it had a positive impact on digestion performance with higher VSR and odor control with reduced H2S and TVOSCs in the headspace gas of dewatered biosolids considered in the tests. Ferric chloride is considered a beneficial additive as a strategy for an odor mitigation, not to mention more efficient digestion under anaerobic conditions.
    Full-text · Article · Dec 2013 · Water Science & Technology
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    ABSTRACT: Water resource recovery facilities have been described as creating breeding ground conditions for the selection, transfer, and dissemination of antibiotic resistance genes (ARGs) among various bacteria. The objective of this study was to determine the effect of direct addition of antibiotic and silver nanoparticles (Ag NPs, or nanosilver) on the occurrence of ARGs in thermophilic anaerobic digesters. Test thermophilic digesters were amended with environmentally-relevant concentrations of Ag NP (0.01, 0.1, and 1.0 mg-Ag/L; corresponding to approximately 0.7, 7.0, and 70 mg-Ag/kg total solids) and sulfamethoxazole (SMX) that span susceptible to resistant classifications (1, 5, and 50 mg/L) as potential selection pressures for ARGs. Tetracycline (tet(O), tet(W)) and sulfonamide (sulI, sulII) ARGs and the integrase enzyme gene (intI1) associated with Class 1 integrons were measured in raw sludge, test thermophilic digesters, a control thermophilic digester, and a control mesophilic digester. There was no apparent effect of Ag NPs on thermophilic anaerobic digester performance. The maximum SMX addition (50 mg/L) resulted in accumulation of volatile fatty acids and low pH, alkalinity, and volatile solids reduction. There was no significant difference between ARG gene copy numbers (absolute or normalized to 16S rRNA genes) in amended thermophilic digesters and the control thermophilic digester. Antibiotic resistance gene copy numbers in digested sludge ranged from 10(3) to 10(6) copies per microL (approximately 8 x10(1) to 8 x 10(4) copies per microg) of sludge as result of a 1-log reduction of ARGs (2-log reduction for intI1). Quantities of the five ARGs in raw sludge ranged from 10(4) to 10(8) copies per microL (approximately 4 x 10(2) to 4 x 10(6) per microg) of sludge. Test and control thermophilic digesters (53 degrees C, 12-day solids retention time [SRT]) consistently reduced but did not eliminate levels of all analyzed genes. The mesophilic digester (37 degrees C, 20-day SRT) also reduced levels of sulI, sulII, and intI1 genes, but levels of tet(O) and tet(W) were the same or higher than in raw sludge. Antibiotic resistance gene reductions remained constant despite the application of selection pressures, which suggests that digester operating conditions are a strong governing factor of the bacterial community composition and thus the prevalence of ARGs.
    Full-text · Article · May 2013 · Water Environment Research
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    ABSTRACT: Landfill leachates strongly quench UV light. When discharged to POTWs, leachates can interfere with UV disinfection. To investigate the UV quenching problem of landfill leachates, a variety of landfill leachates with a range of conditions were collected and characterized. The UV blocking component was found to be resistant to biological degradation so they pass through wastewater treatment plants and impact the subsequent UV disinfection system. Leachate samples were fractionated into humic acids (HAs), fulvic Acids (FAs) and hydrophilic (Hpi) fractions to investigate the source of UV absorbing materials. Results show that for all leachates examined, the specific UV254 absorbance (SUVA254) of the three fractions follows: HA>FA>Hpi. However, the overall UV254 absorbance of the Hpi fraction was important because there was more hydrophilic organic matter than humic or fulvic acids. The size distribution was also investigated to provide information about the potential for membrane treatment. It was found that the size distribution of the three fractions follows: HA>FA>Hpi. This indicates that membrane separation following biological treatment is a promising technology for removal of humic substances from landfill leachates. Leachate samples treated in this manner could meet the UV transmittance requirement of the POTWs.
    No preview · Article · Apr 2013 · Journal of hazardous materials
  • Renzun Zhao · John T Novak · C. Douglas Goldsmith
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    ABSTRACT: To explore the feasible treatment alternatives for organic contaminant, especially organic arsenic species in the landfill gas (LFG) condensate, a variety of treatment approaches were examined and evaluated in this study. Biological degradation, conventional and advanced oxidation, and physical absorption showed limited effectiveness to convert the methylated arsenic to inorganic arsenic. Reverse osmosis (RO) was found to be able to remove the organic arsenic and meet the discharge limits. Maximum removal efficiency and cost level were summarized for all treatment approaches tested, which can be a reference for the organic arsenic treatment method selection under different circumstances.
    No preview · Article · Feb 2013 · Waste Management
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    ABSTRACT: When discharged to publically owned treatment works (POTWs), landfill leachates can interfere with the installed treatment facilities. Biological treatment is ineffective for the removal of some of the bio-refractory organic matter, such as UV254 quenching substances and inorganic nitrogen species. Fenton's reagent treatment for biologically treated landfill leachates is examined in this study. The mechanism and optimum conditions for the Fenton's reagent treatment are also explored. The particle size and hydrophobic nature based fractions of the Fenton's treated leachate samples were analyzed to provide insight into the leachate fractions targeted by the Fenton's reagent. The results indicated that the Fenton's reagent can act as a good compensation for the biological treatment as it can remove leachate fractions which are widely considered to be bio-refractory. It can achieve good UV254 absorbance removal rates which can help solve the UV254 quenching problem due to the leachates at the POTWs.
    No preview · Article · Jan 2013
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    ABSTRACT: This study evaluated the relationship between concentrations of operationally defined potentially bioavailable organic ‐carbon (PBOC) and hydrolyzable amino acids (HAAs) in sediments collected from a diverse range of chloroethene‐‐contaminated sites. Concentrations of PBOC and HAA were measured using aquifer sediment samples collected at six selected study sites. Average concentrations of total HAA and PBOC ranged from 1.96 ± 1.53 to 20.1 ± 25.6 mg/kg and 4.72 ± 0.72 to 443 ± 65.4 mg/kg, respectively. Results demonstrated a statistically significant positive relationship between concentrations of PBOC and total HAA present in the aquifer sediment (p Document Type: Research Article DOI: http://dx.doi.org/10.1111/j.1745-6592.2012.01406.x Publication date: November 1, 2012 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher In this Subject: Geology By this author: Thomas, Lashun K. ; Widdowson, Mark A. ; Novak, John T. ; Chapelle, Francis H. ; Benner, Ronald ; Kaiser, Karl GA_googleFillSlot("Horizontal_banner_bottom");
    Full-text · Article · Nov 2012 · Ground Water Monitoring and Remediation
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    ABSTRACT: Recent studies have demonstrated that wastewater treatment plants (WWTPs) significantly alter the magnitude and distribution of antibiotic resistance genes (ARGs) in receiving environments, indicating that wastewater treatment represents an important node for limiting ARG dissemination. This study examined the potential for membrane treatment of microconstituent ARGs and the effect of native wastewater colloids on the extent of their removal. Plasmids containing vanA (vancomycin) and bla(TEM) (β-lactam) ARGs were spiked into three representative WWTP effluents versus a control buffer and tracked by quantitative polymerase chain reaction through a cascade of microfiltration and ultrafiltration steps ranging from 0.45 μm to 1 kDa. Significant removal of ARGs was achieved by membranes of 100 kDa and smaller, and presence of wastewater colloids resulted in enhanced removal by 10 kDa and 1 kDa membranes. ARG removal was observed to correlate significantly with the corresponding protein, polysaccharide, and total organic carbon colloidal fractions. Alumina membranes removed ARGs to a greater extent than polyvinylidene fluoride membranes of the same pore size (0.1 μm), but only in the presence of wastewater material. Control studies confirmed that membrane treatment was the primary mechanism of ARG removal, versus other potential sources of loss. This study suggests that advanced membrane treatment technology is promising for managing public health risks of ARGs in wastewater effluents and that removal may even be enhanced by colloids in real-world wastewaters.
    Full-text · Article · Oct 2012 · Water Research
  • Renzun Zhao · John T Novak · C Douglas Goldsmith
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    ABSTRACT: A cost effective and widely applied approach for landfill leachate disposal is to discharge it to a municipal wastewater treatment plant (WWTP). The recalcitrant nature of leachate organics and the impact on the downstream WWTPs were comprehensively investigated in this study. Size fractionation by ultrafiltration (UF) and microfiltration (MF) was employed in conjunction with various analyses (TOC, COD, nitrogen species and UV(254) absorbance) on raw and biologically treated landfill leachates to provide insight into biological treatability. Overall, landfill leachate organics showed bio-refractory properties. Less than half of the organic matter, measured as total organic carbon (TOC), could be removed in the biological processes examined. Size distribution data showed that the <1 thousand Daltons (kDa) fraction is dominant in most untreated and treated landfill leachates, indicating difficulties for membrane treatment. Also, most removal occurred for the <1 kDa fraction in the biological processes, while the intermediate size fractions increased slightly. This may be caused by bio-flocculation and/or partial degradation of larger molecular weight fractions. Organic nitrogen was investigated in this study as one of the first explorations for landfill leachates. Organic nitrogen in landfill leachates was more bio-refractory than other organic matter. UV quenching by landfill leachates was also investigated since it interferes with the UV disinfection at WWTPs. The combination of activated carbon and activated sludge (PACT) showed some effectiveness for reducing UV quenching, indicating that carbon adsorption is a potential method for removal of UV quenching substances. Fourier transform Infrared (FT/IR) data showed that aromatic groups are responsible for the UV quenching phenomenon.
    No preview · Article · Apr 2012 · Water Research
  • Jongmin Kim · John T. Novak
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    ABSTRACT: The performance of temperature phased anaerobic digestion system (TPAD) was compared to the performance of single stage thermophilic and mesophilic anaerobic digestion systems. All 3 digestion systems were operated for the same overall retention time. Feed sludge was pre-digested by the thermophilic aerobic digestion system for 2.5 days. The TPAD system removed greater solids than single stage thermophilic and mesophilic anaerobic digestion systems. However, effluents from the single stage mesophilic anaerobic digestion system was easier to dewater and generated much less organic sulfur odors after dewatering than other 2 digestion systems for the same overall retention time.
    No preview · Article · Jan 2012
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    ABSTRACT: Over the past decade, a series of research studies dealing with odors associated with anaerobically digested biosolids has been supported by the Water Environment Research Foundation. These studies have investigated the causes and intensity of odors, the specific compounds associated with odors, the role of dewatering processes in odor generation and methods for mitigation of odors. As part of this research, methods have been developed to simulate odor generation from dewatering devices, to provide a lab method for odor quantification and to assess a variety of methods for odor reduction. A summary of the highlights of this research are provided.
    Full-text · Article · Jan 2012

Publication Stats

3k Citations
233.82 Total Impact Points

Institutions

  • 1989-2015
    • Virginia Polytechnic Institute and State University
      • • Department of Civil and Environmental Engineering
      • • Department of Crop and Soil Environmental Sciences
      Блэксбург, Virginia, United States
  • 2006
    • Bucknell University
      • Department of Civil and Environmental Engineering
      Lewisburg, Pennsylvania, United States
  • 1999
    • Gannon University
      Erie, Pennsylvania, United States
    • Aalborg University
      Ålborg, North Denmark, Denmark