Inter-institutional laboratory standardization for SARS-CoV-2 surveillance through wastewater-based epidemiology applied to Mexico City.

Objectives: Wastewater-based surveillance applied to SARS-CoV-2 viral load quantification for COVID-19 has become one of the most relevant complementary tools in epidemiologic prevention programs worldwide. However, this valuable decision-making tool still requires fine-tuning to produce comparable results between laboratories, especially when applied to the surveillance of megacities.

Methods: Six laboratories across Mexico and one from the United States executed an interlaboratory study to set up a singular standardized protocol considering method cost, installed infrastructure, materials available, and supply availability for SARS-CoV-2 quantification from five Mexico City sampling sites across this megacity.

Exploring resistomes and microbiomes in pilot-scale microalgae-bacteria wastewater treatment systems for use in low-resource settings.

Antibiotic resistance genes (ARGs) released into the environment are an emerging human and environmental health concern, including ARGs spread in wastewater treatment effluents. In low-to-middle income countries (LMICs), an alternate wastewater treatment option instead of conventional systems are low-energy, high-rate algal ponds (HRAP) that use microalgae-bacteria aggregates (MABA) for waste degradation. Here we studied the robustness of ARG removal in MABA-based pilot-scale outdoor systems for 140 days of continuous operation.

Monitoring of SARS-CoV-2 RNA in wastewater: A surveillance tool to foresee infection's evolution in the Mexican Caribbean.

The study aims to determine SARS-CoV-2 RNA in sewage of Cancun wastewater treatment plants, the main touristic destination of Mexico, and to estimate the infected persons during the sampling period. SARS-CoV-2 RNA traces were detected in the inlet of the five plants during almost all the sampling months. However, there is no presence of SARS-CoV-2 RNA traces in the effluent of the five WWTPs during the study period.

Approaches applied to detect SARS-CoV-2 in wastewater and perspectives post-COVID-19.

Currently, SARS-CoV-2 has been detected in the influent of wastewater treatment plants (WWTP), pumping stations, manholes, sewer networks and sludge of WWTP and facilities of countries as France, Spain, Italy, Netherlands, United States, Australia, Ecuador, Brazil and Japan. Although this virus has been detected in the wastewater streams, there is no robust method for its detection and quantification in wastewater. This review compiled and analyzed the virus concentration approaches applied to detect the SARS-CoV-2, besides to provide insights about the methodology for viral concentration, limit of detection, occurrence, persistence, and perspectives post-COVID-19 related with the implications of the virus presence in wastewater.

Surveillance of SARS-CoV-2 in sewage and wastewater treatment plants in Mexico.

The SARS-CoV-2 virus causing COVID-19 is spread in sewage by the stool of infected individuals, and viral material in sewage can be quantified using molecular tools. This study aimed to monitor the presence of SARS-CoV-2 RNA in sewage in Mexico based on RdRP, S, and N gene analysis. The influent, effluent, and activated sludge from two domestic wastewater treatment plants (WWTP) were evaluated from the early stage of the epidemic to July 2020.

Loop-mediated isothermal amplification-based electrochemical sensor for detecting SARS-CoV-2 in wastewater samples.

The current pandemic COVID-19 caused by the coronavirus SARS-CoV-2, has generated different economic, social and public health problems. Moreover, wastewater-based epidemiology could be a predictor of the virus rate of spread to alert on new outbreaks. To assist in epidemiological surveillance, this work introduces a simple, low-cost and affordable electrochemical sensor to specifically detect N and ORF1ab genes of the SARS-CoV-2 genome.

Continuous anaerobic oxidation of methane: Impact of semi-continuous liquid operation and nitrate load on NO production and microbial community.

This work proves the feasibility of employing regular secondary activated sludge for the enrichment of a microbial community able to perform the anaerobic oxidation of methane coupled to nitrate reduction (N-AOM). After 96 days of activated sludge enrichment, a clear N-AOM activity was observed in the resulting microbial community. The methane removal potential of the enriched N-AOM culture was then studied in a stirred tank reactor (STR) operated in continuous mode for methane supply and semi-continuous mode for the liquid phase.

Thermophilic biogas production from microalgae-bacteria aggregates: biogas yield, community variation and energy balance.

Biogas production through anaerobic mesophilic digestion is the most straightforward biofuel production route integrated into microalgae-bacteria wastewater treatment plants. Improvement of this biofuel route without adding pretreatment units is possible through the temperature increase. This paper presents a comprehensive evaluation of the transitory effect of different temperatures (35 °C and 55 °C) and hydraulic retention times (HRT) of 15 and 30 d on the long-term methane production using non-pretreated microalgae-bacteria aggregates as a feedstock.

A review on the factors influencing biohydrogen production from lactate: The key to unlocking enhanced dark fermentative processes.

Dark fermentation (DF) is one of the most promising biological methods to produce bio-hydrogen and other value added bio-products from carbohydrate-rich wastes and wastewater. However, process instability and low hydrogen production yields and rates have been highlighted as the major bottlenecks preventing further development. Numerous studies have associated such concerns with the inhibitory activity of lactate-producing bacteria (LAB) against hydrogen producers.

Innovative Control of Biofilms on Stainless Steel Surfaces Using Electrolyzed Water in the Dairy Industry.

Biofilms on food-contact surfaces can lead to recurrent contamination. This work aimed to study the biofilm formation process on stainless steel plates used in the dairy industry: 304 surface finish 2B and electropolished; and the effect of a cleaning and disinfection process using alkaline (AEW) and neutral (NEW) electrolyzed water. Milk fouling during heat processing can lead to type A or B deposits, which were analyzed for composition, surface energy, thickness, and roughness, while the role of raw milk microbiota on biofilm development was investigated.

Standardized protocol for determination of biohydrogen potential.

Biohydrogen production potential (BHP) depends on several factors like inoculum source, substrate, pH, among many others. Batch assays are the most common strategy to evaluate such parameters, where the comparison is a challenging task due to the different procedures used. The present method introduces the first internationally validated protocol, evaluated by 8 independent laboratories from 5 different countries, to assess the biohydrogen potential.

Influence of Added Nutrients and Substrate Concentration in Biohydrogen Production from Winery Wastewaters Coupled to Methane Production.

Winery wastewaters are acidic effluents with high content of organic matter and nutrients. Different initial values of chemical oxygen demand (COD), ranging from 4 to 50 g L, were tested in batch assays to evaluate the fermentative hydrogen production followed by a methane production step. The influence of adding a typical nutrient solution for hydrogen production was investigated.

From mesophilic to thermophilic conditions: one-step temperature increase improves the methane production of a granular sludge treating agroindustrial effluents.

Objectives: To assess the effect of one-step temperature increase, from 35 to 55 °C, on the methane production of a mesophilic granular sludge (MGS) treating wine vinasses and the effluent of a hydrogenogenic upflow anaerobic sludge blanket (UASB) reactor.

Results: One-step temperature increase from mesophilic to thermophilic conditions improved methane production regardless of the substrate tested. The biomethane potentials obtained under thermophilic conditions were 1.

Hydrolysis of microalgal biomass using ruminal microorganisms as a pretreatment to increase methane recovery.

The use of ruminal fluid as a source of hydrolytic microorganisms for the pretreatment of a native consortium of microalgae (essentially Senedesmus) was investigated. The hydrolytic enzyme activity of the ruminal culture was first enriched in a bioreactor. Then, using the enriched culture, the effect of the microalgae to the ruminal fluid ratio (S/X) on the hydrolysis and subsequent production of methane was investigated.

Biohydrogen and methane production via a two-step process using an acid pretreated native microalgae consortium.

A native microalgae consortium treated under thermal-acidic hydrolysis was used to produce hydrogen and methane in a two-step sequential process. Different acid concentrations were tested, generating hydrogen and methane yields of up to 45mLHgVS and 432mLCHgVS, respectively. The hydrogen production step solubilized the particulate COD (chemical oxygen demand) up to 30%, creating considerable amounts of volatile fatty acids (up to 10gCODL).

Microbial communities from 20 different hydrogen-producing reactors studied by 454 pyrosequencing.

To provide new insight into the dark fermentation process, a multi-lateral study was performed to study the microbiology of 20 different lab-scale bioreactors operated in four different countries (Brazil, Chile, Mexico, and Uruguay). Samples (29) were collected from bioreactors with different configurations, operation conditions, and performances. The microbial communities were analyzed using 16S rRNA genes 454 pyrosequencing.