Browsing by Author "Tyagi, Vinay Kumar"

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    Advanced steam-explosion pretreatment mediated anaerobic digestion of municipal sludge: effects on methane yield, emerging contaminants removal, and microbial community
    (Elsevier, 2023-09-28) Balasundaram, Gowtham; Gahlot, Pallavi; Ahmed, Banafsha; Biswas, Pinakshi; Tyagi, Vinay Kumar; Svensson, Kine; Kumar, Vinod; Kazmi, A. A.
    Advanced steam explosion pretreatment, i.e., the Thermal hydrolysis process (THP) is applied mainly to improve the sludge solubilization and subsequent methane yield in the downstream anaerobic digestion (AD) process. However, the potential of THP in pretreating the high solids retention time (SRT) sludges, mitigating the risk of emerging organic micropollutants and effects on anaerobic microbiome in digester remains unclear. In this study, sludge from a sequencing batch reactor (SBR) system operating at a SRT of 40 days was subjected to THP using a 5 L pilot plant at the temperature ranges of 120–180 °C for 30–120 min. The effect of THP on organics solubilization, methane yield, organic micropollutant removal, and microbial community dynamics was studied. The highest methane yield of 507 mL CH4/g VSadded and volatile solids (VS) removal of 54% were observed at 160°C- 30min THP condition, i.e., 4.1 and 2.6 times higher than the control (123 mL CH4/gVSadded, 20.7%), respectively. The experimental values of hydrolysis coefficient and methane yield have been predicted using Modified Gompertz, First order, and Logistics models. The observed values fitted well with all three models showing an R2 value between 0.96 and 1.0. THP pretreated sludges showed >80% removal of Trimethoprim, Enrofloxacin, Ciprofloxacin, and Bezafibrate. However, Carbamazepine, 17α-ethinylestradiol, and Progesterone showed recalcitrant behavior, resulting in less than 50% removal. Microbial diversity analysis showed the dominance of Proteobacteria, Firmicutes, Chloroflexi, and Bacteroidetes, collectively accounting for >70–80% of bacterial reads. They are mainly responsible for the fermentation of complex biomolecules like polysaccharides, proteins, and lipids. The THP-mediated anaerobic digestion of sludge shows better performance than the control digestion, improved methane yield, higher VS and micropollutants removal, and a diverse microbiome in the digester.
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    Advances in algal biomass pretreatment and its valorisation into biochemical and bioenergy by the microbial processes
    (Elsevier, 2022-06-09) Bhatia, Shashi Kant; Ahuja, Vishal; Chandel, Neha; Gurav, Ranjit; Bhatia, Ravi Kant; Govarthanan, Muthusamy; Tyagi, Vinay Kumar; Kumar, Vinod; Pugazendhi, Arivalagan; Banu, J. Rajesh; Yang, Yung-Hun
    Urbanization and pollution are the major issues of the current time own to the exhaustive consumption of fossil fuels which have a detrimental effect on the nation's economies and air quality due to greenhouse gas (GHG) emissions and shortage of energy reserves. Algae, an autotrophic organism provides a green substitute for energy as well as commercial products. Algal extracts become an efficient source for bioactive compounds having anti-microbial, anti-oxidative, anti-inflammatory, and anti-cancerous potential. Besides the conventional approach, residual biomass from any algal-based process might act as a renewable substrate for fermentation. Likewise, lignocellulosic biomass, algal biomass can also be processed for sugar recovery by different pre-treatment strategies like acid and alkali hydrolysis, microwave, ionic liquid, and ammonia fiber explosion, etc. Residual algal biomass hydrolysate can be used as a feedstock to produce bioenergy (biohydrogen, biogas, methane) and biochemicals (organic acids, polyhydroxyalkanoates) via microbial fermentation.
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    Energy feasibility and life cycle assessment of sludge pretreatment methods for advanced anaerobic digestion
    (Elsevier, 2022-05-26) Balasundaram, Gowtham; Vidyarthi, Praveen Kumar; Gahlot, Pallavi; Arora, Pratham; Kumar, Vinod; Kumar, Manish; Kazmi, A. A.; Tyagi, Vinay Kumar
    Energy sustainability is one of the critical parameters to be studied for the successful application of pretreatment processes. This study critically analyzes the energy efficiency of different energy-demanding sludge pretreatment techniques. Conventional thermal pretreatment of sludge (∼5% total solids, TS) produced 244 mL CH4/gTS, which could result in a positive energy balance of 2.6 kJ/kg TS. However, microwave pretreatment could generate only 178 mL CH4/gTS with a negative energy balance of −15.62 kJ/kg TS. In CAMBI process, the heat requirements can be compensated using exhaust gases and hot water from combined heat and power, and electricity requirements are managed by the use of cogeneration. The study concluded that <100 ℃ pretreatment effectively enhances the efficiency of anaerobic digestion and shows positive energy balance over microwave and ultrasonication. Moreover, microwave pretreatment has the highest global warming potential than thermal and ultrasonic pretreatments.
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    Enhanced combined assimilative and bound phosphorus uptake in concurrence with nitrate removal in pre-anoxic cyclic sequencing batch reactor
    (Elsevier, 2022-09-21) Khursheed, Anwar; Ali, Muntjeer; Munshi, Faris Mohammad A.; Alali, Abdulrhman Fahmi; Kamal, Mohab Amin; Almohana, Abdulaziz Ibrahim; Alrehaili, Omar; Gaur, Rubia Z.; Tyagi, Vinay Kumar; Khan, Abid Ali; Goel, Gaurav
    Needless to specify, controlling nitrogen and phosphorus discharge from wastewater treatment plants is synonymous with the prevention of eutrophication of surface waters, as one of the major issues related to water security. The present study investigates the performance of a pre-anoxic sequencing batch reactor (SBR) working on the basis of intermittent aeration, operated at varied carbon (bCOD) to nitrogen (C/N) ratio of 3, 7.5, and 10, and readily biodegradable (rbCOD) to slowly biodegradable (sbCOD) ratio of 0.1, 0.25, and 0.5. The findings revealed that an enhanced nitrogen removal was observed, together with higher C/N and rbCOD to sbCOD ratios. The results also show a consistent increase in total phosphorus removal with an increase in nitrogen removal. The phosphorus uptake of sludge varied from 0.02 – 0.045 mgP/mgVSS (avg. 0.031 ± 0.004), which resulted in enrichment levels of 0.88 – 1.68 times the stoichiometric value of 0.0267 mgP/mgVSS (avg. 1.45 ± 0.14). On an average basis, the assimilative total phosphate (TP) content was increased by 0.008 gTP/gNO -/3 -N removal rate. The excess phosphorus removal was due to the formation of poorly soluble polyvalent phosphate compounds, which was found based on dry analysis, which persisted as bound phosphate in the sludge.
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    Polyhydroxyalkanoates synthesis using acidogenic fermentative effluents
    (Elsevier, 2021-11-11) Banu, J. Rajesh; Ginni, G.; Kavitha, S.; Kannah, R. Yukesh; Kumar, Vinod; Kumar, S. Adish; Gunasekaran, M.; Tyagi, Vinay Kumar; Kumar, Gopalakrishnan
    Polyhydroxyalkanoates (PHA) are natural polyesters synthesized by microbes which consume excess amount of carbon and less amount of nutrients. It is biodegradable in nature, and it synthesized from renewable resources. It is considered as a future polymer, which act as an attractive replacement to petrochemical based polymers. The main hindrance to the commercial application of PHA is the high manufacturing cost. This article provides an overview of different cost-effective substrates, their characteristics and composition, major strains involved in economical production of PHA and biosynthetic pathways leading to accumulation of PHA. This review also covers the operational parameters, various fermentative modes including batch, fed-batch, repeated fed-batch and continuous fed-batch systems, along with advanced feeding strategies such as single pulse carbon feeding, feed forward control, intermittent carbon feeding, feast famine conditions to observe their effects for improving PHA synthesis and associated challenges. In addition, it also presents the economic analysis and future perspectives for the commercialization of PHA production process thereby making the process sustainable and lucrative with the possibility of commercial biomanufacturing.
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    Progress in microalgal mediated bioremediation systems for the removal of antibiotics and pharmaceuticals from wastewater
    (Elsevier, 2022-02-16) Chandel, Neha; Ahuja, Vishal; Gurav, Ranjit; Kumar, Vinod; Tyagi, Vinay Kumar; Pugazhendhi, Arivalagan; Kumar, Gopalakrishnan; Kumar, Deepak; Yang, Yung-Hun; Bhatia, Shashi Kant
    Worldwide demand for antibiotics and pharmaceutical products is continuously increasing for the control of disease and improvement of human health. Poor management and partial metabolism of these compounds result in the pollution of aquatic systems, leading to hazardous effects on flora, fauna, and ecosystems. In the past decade, the importance of microalgae in micropollutant removal has been widely reported. Microalgal systems are advantageous as their cultivation does not require additional nutrients: they can recover resources from wastewater and degrade antibiotics and pharmaceutical pollutants simultaneously. Bioadsorption, degradation, and accumulation are the main mechanisms involved in pollutant removal by microalgae. Integration of microalgae-mediated pollutant removal with other technologies, such as biodiesel, biochemical, and bioelectricity production, can make this technology more economical and efficient. This article summarizes the current scenario of antibiotic and pharmaceutical removal from wastewater using microalgae-mediated technologies.
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    Technological advancements in valorization of second generation (2G) feedstocks for bio-based succinic acid production
    (Elsevier, 2022-07-08) Narisetty, Vivek; Okibe, Maureen Chiebonam; Amulya, K.; Jokodola, Esther Oreoluwa; Coulon, Frederic; Tyagi, Vinay Kumar; Lens, Piet N. L.; Parameswaran, Binod; Kumar, Vinod
    Succinic acid (SA) is used as a commodity chemical and as a precursor in chemical industry to produce other derivatives such as 1,4-butaneidol, tetrahydrofuran, fumaric acid, and bio-polyesters. The production of bio-based SA from renewable feedstocks has always been in the limelight owing to the advantages of renewability, abundance and reducing climate change by CO2 capture. Considering this, the current review focuses on various 2G feedstocks such as lignocellulosic biomass, crude glycerol, and food waste for cost-effective SA production. It also highlights the importance of producing SA via separate enzymatic hydrolysis and fermentation, simultaneous saccharification and fermentation, and consolidated bioprocessing. Furthermore, recent advances in genetic engineering, and downstream SA processing are thoroughly discussed. It also elaborates on the techno-economic analysis and life cycle assessment (LCA) studies carried out to understand the economics and environmental effects of bio-based SA synthesis.