Thermal pretreatment of Lantana camara for improved biogas production: Process parameter studies for energy evaluation.

The rigid lignocellulosic structure of Lantana camara impedes the hydrolysis phase and reduces the biogas production during anaerobic digestion of Lantana camara. Hence, the current study focuses on the impact of various heating pretreatment techniques, viz., hot air oven (HAO), autoclave (ATC), hot water bath (HWB), and microwave (MCW) on L. camara to speed up hydrolysis and boost up biogas production. ATC pretreatment of L. camara was witnessed to be most efficient compared to HAO, MCW, and HWB pretreatment. ATC pretreatment enhanced the solubilization (45.44%), and an increment in volatile fatty acids (VFA) was observed (56.75%) at 110 °C for 80 min when correlated to the untreated (control). Cumulative methane production following ATC pretreatment had risen to 3656 mL in 5 weeks from 2895 mL in 7 weeks. Thermal pretreatment of Lantana camara broke down the rigid lignocellulosic structure, accelerating the hydrolysis stage and improving biogas production simultaneously. To the best of our knowledge, this is the first thermal pretreatment study conducted on Lantana camara for biogas production.

Tracking the temporal variation of COVID-19 surges through wastewater-based epidemiology during the peak of the pandemic: A six-month long study in Charlotte, North Carolina.

The global spread of SARS-CoV-2 has continued to be a serious concern after WHO declared the virus to be the causative agent of the coronavirus disease 2019 (COVID-19) a global pandemic. Monitoring of wastewater is a useful tool for assessing community prevalence given that fecal shedding of SARS-CoV-2 occurs in high concentrations by infected individuals, regardless of whether they are asymptomatic or symptomatic. Using tools that are part of wastewater-based epidemiology (WBE) approach, combined with molecular analyses, wastewater monitoring becomes a key piece of information used to assess trends and quantify the scale and dynamics of COVID-19 infection in a specific community, municipality, or area of service. This study investigates a six-month long SARS-CoV-2 RNA quantification in influent wastewater from four municipal wastewater treatment plants (WWTP) serving the Charlotte region of North Carolina (NC) using both RT-qPCR and RT-ddPCR platforms. Influent wastewater was analyzed for the nucleocapsid (N) genes N1 and N2. Both RT-qPCR and RT-ddPCR performed well for detection and quantification of SARS-CoV-2 using the N1 target, while for the N2 target RT-ddPCR was more sensitive. SARS-CoV-2 concentration ranged from 103 to 105 copies/L for all four plants. Both RT-qPCR and RT-ddPCR showed a significant positive correlation between SARS-CoV-2 concentrations and the 7-day rolling average of clinically reported COVID-19 cases when lagging 5 to 12 days (ρ = 0.52-0.92, p < 0.001-0.02). A major finding of this study is that RT-qPCR and RT-ddPCR generated SARS-CoV-2 data that was positively correlated (ρ = 0.569, p < 0.0001) and can be successfully used to monitor SARS-CoV-2 signals across the WWTP of different sizes and metropolitan service functions without significant anomalies.

Implementing building-level SARS-CoV-2 wastewater surveillance on a university campus.

The COVID-19 pandemic has been a source of ongoing challenges and presents an increased risk of illness in group environments, including jails, long-term care facilities, schools, and residential college campuses. Early reports that the SARS-CoV-2 virus was detectable in wastewater in advance of confirmed cases sparked widespread interest in wastewater-based epidemiology (WBE) as a tool for mitigation of COVID-19 outbreaks. One hypothesis was that wastewater surveillance might provide a cost-effective alternative to other more expensive approaches such as pooled and random testing of groups. In this paper, we report the outcomes of a wastewater surveillance pilot program at the University of North Carolina at Charlotte, a large urban university with a substantial population of students living in on-campus dormitories. Surveillance was conducted at the building level on a thrice-weekly schedule throughout the university's fall residential semester. In multiple cases, wastewater surveillance enabled the identification of asymptomatic COVID-19 cases that were not detected by other components of the campus monitoring program, which also included in-house contact tracing, symptomatic testing, scheduled testing of student athletes, and daily symptom reporting. In the context of all cluster events reported to the University community during the fall semester, wastewater-based testing events resulted in the identification of smaller clusters than were reported in other types of cluster events. Wastewater surveillance was able to detect single asymptomatic individuals in dorms with resident populations of 150-200. While the strategy described was developed for COVID-19, it is likely to be applicable to mitigation of future pandemics in universities and other group-living environments.

Electrohydrolysis pretreatment of water hyacinth for enhanced hydrolysis.

This study investigates the use of electrohydrolysis pretreatment on water hyacinth to cut short the hydrolysis step and increase biogas production at the same time. Electrohydrolysis pretreatment of water hyacinth at 20V for 60min exhibited improved solubilisation (42.9%). Therefore, bio-chemical methane potential (BMP) test was carried out between water hyacinth pretreated at 20V for 60min and untreated water hyacinth. By the end of 30days, cumulative methane production of 2455±17mL CH4/g VS for electrohydrolysis pretreated substrate and 1936±27mL CH4/g VS for the untreated substrate was achieved. Compositional analysis and characterization study revealed the efficiency of electrohydrolysis pretreatment in melting the lignin and lowering the cellulose crystallinity of water hyacinth.

Effect of various types of thermal pretreatment techniques on the hydrolysis, compositional analysis and characterization of water hyacinth.

The aim of this work was to study the effect of four different types of thermal pretreatment techniques i.e., hot air oven, microwave, autoclave and hot water bath on the hydrolysis, compositional analysis and characterization of water hyacinth. To determine the most efficient thermal pretreatment technique exhibiting enhanced solubilisation. Highest solubilisation was achieved by hot air oven (55.5%), followed by microwave, hot water bath and autoclave. Bio-chemical methane potential (BMP) test of hot air oven pretreated and untreated water hyacinth was conducted. Cumulative methane production of 3039±32mLCH4/gVS was achieved by hot air oven pretreated water hyacinth at 90°C for 1h which was way higher than the cumulative methane production of untreated water hyacinth 2396±19mLCH4/gVS on the 35th day. Compositional analysis and characterization of water hyacinth were also investigated to study the changes in the pretreated samples.