Sewage Production Research Articles

Dissolved organic carbon (DOC) and labile organic compounds' spatial and temporal variations in coastal Indian groundwater: their bioavailability and transfer to neighboring coastal waters of India.

Submarine groundwater drainage (SGD) changes the elemental composition of the neighboring coastal ocean and impacts the biogeochemical cycles. To examine the seasonal and spatial variability in dissolved organic carbon (DOC) and labile organic compound biochemical compounds like dissolved carbohydrates (TDCHO), dissolved proteins (TDPRO), and dissolved free amino acid (TDFAA) concentrations during the dry and wet periods, groundwater samples were taken at 90 locations (180 samples) along the Indian coast. The mean DOC contents in Indian coastal groundwaters were more significant than the global mean values. DOC, TDCHO, TDPRO, and TDFAA concentrations are higher during wet than dry periods. The DOC and labile organic compound showed a substantial positive association with soil organic carbon, and respective labile compounds in soil, population, and land usage and poor relation with woodland territories, implying that soil organic compounds leaching is a source of DOC and other labile organic compounds into the groundwater. DOC and other labile compounds concentrations were linearly associated with population density, land usage, and sewage production, demonstrating that anthropogenic activities tightly regulate the formation of DOC in groundwater. During the wet and dry periods, total labile organic compounds (TDCHO, TDFAA, and TDPRO) constituted 21% and 10.5% of DOC, respectively. Compared to the wet time, more aromatic compounds accumulated during the dry season but were less bioavailable. SGD DOC flux contributed 2-7% of riverine DOC flux to the coastal ocean. The SGD flux from the Indian subcontinent to the nearby northern Indian Ocean accounts for approximately 2% of the worldwide SGD flux. The effect of DOC flux via SGD on coastal bacterial activity, the plankton food web, and the oxygen minimum zone must be studied.

Carbide slag and sodium metasilicate synergistic activation of sludge ash-based alkali-activated materials: Towards a cleaner activation approach

Traditional activators such as sodium hydroxide and sodium silicate are commonly used in the preparation of alkali-activated materials; however, their significant environmental impact, high cost, and operational risks limit their sustainable use in treating solid waste. This study explores the innovative use of carbide slag (CS) and sodium metasilicate (NS) as alternative activators in the production of sewage sludge ash-based alkali-activated materials (SSAM) with the aim of reducing the carbon footprint of the preparation process. The results demonstrate that CS effectively activates the sewage sludge ash, enhancing the compressive strength of the SSAM to 40 MPa after curing for 28 d. When used in conjunction with NS, it synergistically improves the mechanical properties. Furthermore, the microstructure and phase composition of the SSAM are characterized. Increasing the quantities of CS and NS accelerates the dissolution of the precursor materials, promoting the formation of a higher quantity of hydration products. This significantly reduces the number of voids and defects within the samples, further enhancing the densification of the microstructure. Environmental assessments reveal that CS and NS offer substantial sustainability benefits, confirming the feasibility of activating SSAM using these materials. This approach provides a less energy-intensive and more environmentally friendly alternative to conventional activation methods and presents an effective strategy for managing large volumes of sewage sludge ash and CS.

Development of New Series of Certified Reference Materials for Ferrosilicon Magnesium Alloys

This paper presents a practical approach to the production of certified reference materials (CRMs) for ferrosilicon magnesium alloys. These new CRMs are predicted to be used in fast X-ray fluorescence spectrometry (XRF) analysis, which does not require sample digestion and does not result in the production of acidic sewage and emissions, contrary to the classical and instrumental techniques currently used in laboratories. Four new certified reference materials (CRMs) were developed to fill the gap in the reference materials market and ensure fast and traceable analyses. The materials were produced with an industrial process and then homogenized and mixed to achieve the required compositions and level of homogeneity. The homogeneity was determined using specially developed analytical methods and confirmed statistically by ANOVA. Additionally, the results of the tests show the short- and long-term stabilities of the new materials. The certified values for specific element contents were determined in interlaboratory tests. All results were assessed statistically for outliers. The results from three or more independent and different analytical methods were used for the calculations. In parallel homogeneity, the stability, and characterization standard uncertainties were calculated and used in the estimation of the final expanded uncertainties of the certified values. Finally, four new CRMs were assisted with the proper certificates according to ISO standards.

Enhancing hydrogen production capability from urine-containing sewage through optimization of urea oxidation pathways

The electrochemical urea oxidation reaction (UOR) represents a promising route to sustainable hydrogen production and reuse of urea-containing sewage. However, the efficiency of UOR is hindered by the dehydrogenation of intermediate *CONH2NH and the conversion of toxic intermediate the *CO. Herein, we report a robust strategy to elevate UOR performance by introducing iron (Fe) atoms into the Ni3S2@NiSe2 heterojunctions (denoted Fe-Ni3S2@NiSe2). The Fe-Ni3S2@NiSe2 exhibits remarkable selectivity and electrocatalytic activity towards UOR, attributed to its reconstruction into Fe-NiOOH species during UOR process, as confirmed by in-situ Raman technology. Utilizing Fe-Ni3S2@NiSe2 as both the cathode and anode in a single-chamber electrolytic cell, the hydrogen production rate reaches 588.4 μmol h−1 in simulated urea-containing sewage and 432.1 μmol h−1 in actual human urine, respectively. Notably, in both scenarios, no oxygen product is detected, and the hydrogen production efficiency surpasses that of traditional water splitting by 5.8-fold and 4.3-fold, respectively. In-situ infrared spectroscopy study reveals that the UOR process involves the cleavage of C-N bond and the generation of CO2. Density functional theory calculations further signifies that the incorporation of Fe facilitates the dehydrogenation of *CONH2NH intermediates, strengthens the d-p hybridization, and weakens O-H bonds, thereby resulting in reduced energy barriers for UOR. Our strategy holds promise for efficient hydrogen production from sewage via UOR, offering potential implications for wastewater treatment and clean energy generation.

Research on the Resource Recovery of Medium-Chain Fatty Acids from Municipal Sludge: Current State and Future Prospects.

The production of municipal sludge is steadily increasing in line with the production of sewage. A wealth of organic contaminants, including nutrients and energy, are present in municipal sludge. Anaerobic fermentation can be used to extract useful resources from sludge, producing hydrogen, methane, short-chain fatty acids, and, via further chain elongation, medium-chain fatty acids. By comparing the economic and use values of these retrieved resources, it is concluded that a high-value resource transformation of municipal sludge can be achieved via the production of medium-chain fatty acids using anaerobic fermentation, which is a hotspot for future research. In this study, the selection of the pretreatment method, the method of producing medium-chain fatty acids, the influence of the electron donor, and the technique used to enhance product synthesis in the anaerobic fermentation process are introduced in detail. The study outlines potential future research directions for medium-chain fatty acid production using municipal sludge. These acids could serve as a starting point for investigating other uses for municipal sludge.

History of anthropogenic faece and sewage contamination to Lake Erhai in southwestern China over the past ∼200 years

Over the past decades, faece and sewage pollution from agricultural and industrial activities has induced severe eutrophication and ecosystem deterioration of Lake Erhai in southwestern China. Investigations on the anthropogenic faece and sewage input from both spatial and historical viewpoints are of great values for recovery strategies. In this study, we investigated fecal steroids in surface sediments from Lake Erhai collected in 2018, and found that the faece and sewage contamination is mainly from the southern region due to urban development, while the raw sewage contributes more in the northern region due to agriculture activities. We further applied fecal steroids to reconstruction of faece and sewage contamination to Lake Erhai over the past ∼200 years. The concentrations in fecal steroids remained low during ∼1820–1970, started to increase since the 1970s, and further increased after the 1990s, indicating a cumulative effect of contamination on the lake ecosystem by agricultural activities and urbanization practices. Diagnostic ratios of faece and sewage contamination over in-situ productivity remained stable or even decreased slightly during ∼1970–1980, and significantly increased during ∼1980–2008, suggesting that the contamination in Lake Erhai began at the 1980s. The fecal steroid records also demonstrated that even though anaerobic sewage treatment was in process, production of raw sewage still exceeded sewage treatment after the 1980s. Considerable faece and sewage contamination in the Lake Erhai catchment from anthropogenic industrialization and urbanization, which has also been observed from various environments throughout the world, asks for further efforts on regulations to protect water quality and human life. Fortunately, governmental regulations have significantly reduced the anthropogenic faece and sewage contamination to Lake Erhai over the past decades, highlighting a crucial role of sustainable management on lake ecosystem.

Characteristics and Impact Evaluation of Hydrological and Water Quality Changes in the Northern Plain of Cixi, Eastern China, from 2010 to 2022

This paper analyzes the spatiotemporal changes and patterns of a regional water environment based on the hydrological and water quality monitoring times and the geographical locations of the monitoring sections in the research area, the plain of Cixi, eastern China. Based on the calculation of runoff generation and concentration in the coastal plain river network and based on the characteristics and impact evaluation of the regional water pollution, the migration and diffusion mechanisms of surface water pollutants were studied for different sources and characteristics of pollutants entering the river in different river sections. The analytic results show that the water environment and water resource security of the coastal plain mainly cause the problem of eutrophication in the water bodies, and the input of nitrogen and phosphorus from land sources is the main cause of eutrophication in the water bodies, mainly including the production and discharge of domestic sewage, nutrient loss in aquaculture water bodies, affecting agricultural activities, etc. The evaluation also demonstrates that with the development of coastal zones and the rapid development of coastal towns, as the population in coastal plain areas continues to increase, industrial development and population growth are the main driving factors for water quality changes.

Preparation of NaCl Particles Added Polyvinylidene Fluoride Microporous Filter and a Simple Filtration Device

Clean and pollution-free water plays a crucial role in human metabolism and is essential for everyone’s daily life. However, with industrialization, a significant amount of sewage has been produced for many years. Water resources tend to become stressed when the rate of sewage production speed is purified. Many researchers are working on sewage purification to eliminate this hidden danger. It is urgent to find an efficient, high-speed, and environmental way to purify sewage. The objective of this study is to investigate the impact of pore morphology on filtration. In addition, a Polyvinylidene fluoride (PVDF)-microporous filter (MPF) based on non-solvent-induced phase separation (NIPS) and vapor-induced phase separation (VIPS) methods was designed, the morphology and properties of a series of sodium chloride particles (NaCl-ps) added PVDF-MPF was researched, and a simple semi-automatic filtration device based on the character of this PVDF-MPF was manufactured. According to the light transmittance of filtered sewage through PVDF-MPF and NaCl-ps added PVDF-MPF, both PVDF-MPFs can remove particles in sewage. However, after adding NaCl-ps, the purification capacity of PVDF-MPF is higher than that of PVDF-MPF without adding NaCl-ps. The addition of NaCl-ps changes the morphology and improves the sewage purification capacity of PVDF-MPF.

Toxoplasma gondii in Marine Life of Italian Coasts, What Do We Know So Far?

Coastal areas of Italy experience high anthropogenic pressure, with a population density estimated to be 360 people per km2. This is correlated with the production of sewage or surface runoff of water contaminated with Toxoplasma gondii oocysts and other pathogens that can in turn enter the food chain and become a public health concern. Therefore, in the present study, we want to review the current knowledge on the presence of T. gondii in Italian coastal areas. The majority of research in Italy has been carried out on marine mammals, while fishes and mollusks have less often been screened. So far, T. gondii has been found in all sea animals tested, with genotypes II and III as well as atypical genotypes being the most commonly found when screened. However, more information is needed. We encourage routine screening of mollusks and fish that are sold in different food markets throughout the country in order to add information on the distribution of T. gondii and other parasites, preventing possible future outbreaks.

Prediction of rural domestic water and sewage production based on automated machine learning in northern China

Determining the rural domestic water consumption (RDWS, L/person-day) and rural sewage production (RSP, L/person-day) of rural residents at the county scale can provide decision support for rural domestic sewage treatment. However, methods for predicting county-scale RDWS and RSP based on geographical, social, and governance factors are rarely reported. This paper proposes an RDWS and RSP prediction method based on Automated Machine Learning (AutoML) for the Inner Mongolia Autonomous Region. The RDWS and RSP in the Inner Mongolia Autonomous Region were successfully predicted from multi-source data. The AutoML model accurately predicted RDWS (mean absolute error = 1.7072, R2 = 0.7759) and RSP (mean absolute error = 0.6580, R2 = 0.65107). Average years of education (AYOS), proportion of resident population, and proportion of elderly and children (POEAC) were key driving factors related to RDWS prediction. The most important factors associated with RSP prediction were AYOS, POEAC, and annual average precipitation (AAP). An explanatory analysis further revealed dependence between the input variables, RDWS, and RSP. The framework was demonstrated to be a practical tool for qualitative and quantitative analyses of rural domestic water consumption and domestic sewage production in the Inner Mongolia Autonomous Region. Overall, this study provides a solution for predicting county-level RDWS and RSP, providing a reference for the design of rural domestic sewage treatment.

Pollutants production, energy recovery and environmental impact of sewage sludge co-incineration with biomass pellets

This study describes the production of pollutants, energy recovery and environmental impact of the co-incineration of sewage sludge and biomass pellets. The main objective of this study is to describe the use of energy generated by co-incineration and to assess the environmental impact of emitted pollutants. Co-incineration takes place in five different blended. The combustion takes place in a fluidised bed reactor with an average combustion temperature of 915–939 °C. The combustion process is mapped by Fourier transform infrared spectroscopy, Continuous Mercury Monitoring Systems, thermocouples, pressures, and flows sensors. The results show that the concentrations of harmful substances, namely SO2 and NOX, reach values of 12.39–1730.33 mg∙m–3N for SO2 and 93.30–1156 mg∙m–3N for NOX. This means that the emission limits are exceeded 40 times for SO2 and 8 times for NOX in the worst case. Regarding heat recovery, the resulting value of potential energy recovery from the flue gas is 5.35–7.69 MJ∙kg–1, and as the sewage sludge content in the fuel increases, the heat recovery value decreases. The resulting values of pollutant concentrations are also analyzed using a life cycle assessment approach using the GaBi software. The results show that sewage sludge incineration has the greatest impact on climate change, terrestrial ecotoxicity, and human toxicity. Again, as the sewage sludge content in the fuel decreases, the hazardousness of the discharged flue gas decreases. This study presents a relatively promising option to use sewage sludge as a secondary fuel in large combustion sources under certain conditions.

A Noxious Weed Ambrosia artemisiifolia L. (Ragweed) as Sustainable Feedstock for Methane Production and Metals Immobilization

Plants of the Ambrosia genus are invasive and cause many ecological problems, including the oppression of the growth of agricultural crops and native plants, land depletion, and the production of strong allergens. The use of weeds as a sustainable feedstock for biogas production, either methane or hydrogen, is a promising way to fulfill the energy needs of the current generation, eliminate the depletion of non-renewable carbon resources, and preserve the ecosystem degradation caused by invasive species impacts. A diversified microbial community was used as inoculum and Ambrosia artemisiifolia L. biomass as a substrate for anaerobic degradation and methane production. In this regard, the development of biotechnological approaches to ragweed degradation will promote the integration of new renewable energy systems. Herein, we have shown the high effectiveness of combining the processes of anaerobic degradation of plant biomass for methane production and detoxification of meal-containing model sewage by a diversified microbial community. Thus, the maximum methane yield was 56.0 L kg−1 TS. The presence of 500 mg L−1 Cu(II) slightly inhibited methane synthesis, and the methane yield was 38.4 L kg−1 TS. In contrast to a diversified microbial community, the natural microbiome of ragweed almost did not synthesize methane and did not degrade plant biomass (Kd = 2.3). Methanogens effectively immobilized Cr(IV), Cu(II), and Fe(III) during ragweed fermentation at initial concentrations of 100–200 mg L−1. The obtained results showed the high effectiveness of applying a diversified microbial community in a sewage treatment plant for the degradation of a noxious plant, Ambrosia artemisiifolia L.

Beach pollution from marine litter: Analysis with the DPSIR framework (driver, pressure, state, impact, response) in Tuscany, Italy

• DPSIR applied to beach contamination through data search and fieldwork. • Fieldwork allowed to gain insight into local pressures, state, and health impact of beach-stranded. • Main local responses: waste removal from drainage system and recycling of stranded material. • Local and regional efforts are required to build a systemic view of beach contamination. Beaches are affected by the accumulation of natural and anthropogenic material; however, this environmental issue has not yet been explored from a One Health perspective. In this paper, the conceptual framework of DPSIR (Drivers-Pressures-State-Impact-Response) was used to understand the beach-stranded material issue in a systemic way and a data-based classification for some environmental indicators was developed to support the DPSIR analysis. The model was applied to an Italian coastal municipality as a case study, through the collection of data from a variety of data sources: publicly accessible database, data from a stakeholders’ network (i.e., coastal authority, solid waste company, sewerage company, drainage consortium), and fieldwork consisting in microbiological analysis of stranded material and underlying sand, visual census of macrolitter along beach and waterways. In the study area, solid wastes production was a high pressure (768 kg/capita/year), but in situ visual observations of floating wastes at the outlet of the canals revealed that the contribution of local waterways to marine litter was negligible, thus suggesting the effectiveness of the measures adopted along local waterways by the drainage consortium (i.e., grids at the drainage pumping stations). Nevertheless, very high quantity of anthropogenic wastes was counted during the beach litter surveys (603 items/100 m), probably as a result of coastal current pathway that transported material from major watercourses (>100 km 2 drainage basin size; 23 items/h). On the contrary, local sewage production represented a very high pressure (>33,000 m 3 /km) that impacted on the microbiological quality of the stranded material with moderate to high level of fecal bacteria indicators detected in the beach cast. The underlying sand was affected by such contamination, with most of the sample within the provisional limit set by WHO for enterococci in beach sand (60 CFU/g) that was associated to a health risk of<5 % of gastroenteritis attributable to accidental ingestion of sand; nevertheless, some enterococci peak values (980 MPN/g) could be associated to a health risk for gastroenteritis>10 %. The beach-stranded material was collected without separating the sand, with annual quantity of 1,243 kg/m, that was processed in a dedicated facility allowing to recover up to 98 % of sand and biomass after the treatment, with moderate expenditure for the coastal municipality (22 €/m). Overall, this study allowed to better figure out the cause-effect relationships underlying the accumulation of stranded material along shoreline and the effectiveness of the management practices toward beach-stranded material. Therefore, the usage of the DPSIR framework as structuring model to understand the problem of stranded material could be useful for beach managers and administrators, and its adoption within beach management programs is worth for improving beach quality.

EVALUASI KONDISI FISIK INSTALASI PENGOLAHAN LUMPUR TINJA (IPLT)

The construction of a Sludge Treatment Plant (IPLT) is one of the efforts made to treat fecal sludge and control pollution to the environment from housing and settlement activities. The city of Sabang already has an IPLT which was built in 2013 but due to the influent of the IPLT which is still very minimal, there is a high idle capacity (100%). The non-operated IPLT causes the condition and function of the processing units to deteriorate. The purpose of this study was to evaluate the condition of the post-construction building, its functionality, and community involvement in the management of IPLT. The research method used is a descriptive method with a quantitative approach in which the data collected in this study is in the form of field observations and the distribution of questionnaires to the policymakers (stakeholders). Technical analysis of data in evaluating the condition of buildings in IPLT through assessment criteria and component weighting using the Analytical Hierarchy Process (AHP) method. The method used in the analysis of the technical aspects by calculating the production of sewage compared to the design capacity. The data analysis technique was carried out using a Likert scale and tested using the Minitab application. The results showed that the condition of the IPLT building was damaged by 35.16% and the IPLT condition was moderately damaged. Alternatives for fulfilling the IPLT capacity can be done by upgrading the septic tank, implementing the Scheduled Sludge Service (LLTT) program, and implementing socialization and education to increase participation in IPLT management.

Research note: Recreational boating, sewage production, and potential implications for phosphorus loading in Lake Champlain

The impacts of recreational boating on lake ecosystems are often not well characterized, including for Lake Champlain (US/Canada) where excess watershed phosphorus loading drives cyanobacteria blooms. Improperly disposed boater-generated sewage has not been considered as a source of phosphorus in total maximum daily load models or implementation plans for the Lake. Surveys of marinas and boaters informed sewage production estimates by marina-using boaters. Annual boater-generated sewage volume was estimated to range between 2,445 and 5,184 m 3 . These volumes allowed estimation of potential phosphorus contributions to Lake Champlain by improperly disposed sewage at varied rates of discharge. Such contributions were negligible compared to known Lake Champlain phosphorus sources, suggesting use of Clean Water Funds to reduce phosphorus inputs may not be warranted. Nonetheless, due to potential for pathogen contamination, continued financial support through other means was recommended to allow marinas to operate and maintain pumpout facilities at rates reasonable to boaters. Improperly disposed sewage was estimated to represent <0.01% of annual phosphorus contributions to Lake Champlain (USA/Canada). As such, Clean Water Funds targeted to address significant phosphorus inputs to the lake may not be warranted. Nonetheless, continued governmental support for marinas to provide and maintain sewage pumpout facilities for free or at rates most boaters were willing to pay is recommended to minimize introduction of pathogens associated with fecal pollution. To further help ensure compliance with sewage disposal regulations, educational materials and messaging to boaters to encourage use of pumpout facilities should be made available in English and French due to significant populations of boaters speaking each language.

Study on hydrogen production of sewage sludge/corncob using chemical looping with Cu‐Fe as oxygen carrier

Study on hydrogen production of sewage sludge/corncob using chemical looping with <scp>Cu‐Fe</scp> as oxygen carrier

Sources of terrestrial nitrogen and phosphorus mobilization in South and South East Asian coastal ecosystems

South and Southeast Asia (SSEA) is a socially, economically and ecologically diverse region, with a rapidly growing population and accelerating industrial development, agricultural intensification using manufactured fertilizers, terrestrial landscape change, expansion of water engineering, sewage production and land conversions. Nitrogen and phosphorus are major nutrients that play an essential role in the eutrophication of inland and coastal water bodies. Eutrophic areas, when combined with appropriate coastal ocean physical conditions, can develop into hypoxic zones that result in long-term ecosystem disruption. This study addressed changes in terrestrial nitrogen and phosphorus mobilization associated with land-use transitions, fertilizer use and sewage from 2002 to 2016 in the SSEA region, with a focus on the Mekong and Krishna-Godavari watersheds. Terrestrial mobilization results from the internal production or addition of reactive, soluble and/or plant available forms of nitrogen and phosphorus. To estimate terrestrial mobilization associated with land conversion, published data were mined for estimates of land cover change effects on soil carbon, nitrogen and phosphorus pools. Data on exogenous fertilizer and sewage effluents were also compiled from the literature. From the analysis, it showed that fertilizer input was the largest source of nitrogen and phosphorus in both case study watersheds. Sewage and land conversion were not a significant source of terrestrial phosphorus mobilization in either watershed. All land conversions resulted in declines in soil carbon, ranging from 11% to 38%. Nitrogen increased, on average by 15%, in conversions of agricultural to urban land, but decreased in all other conversions. Phosphorus increased by 89% in wetland to agriculture conversions, but decreased between 2% and 24% for other land conversions. Expansion of agriculture at the expense of forest was the dominant land conversion in the Mekong watershed. Urbanization, at the expense of agriculture and forest, was the dominant land conversion in the Krishna/Godavari watershed. These results suggest that management of nutrient pollution (N and P) in SSEA will need to focus on reducing the use and/or improving the efficiency of fertilizer use along with regular consolidated monitoring in both watersheds.

Systemic Perspectives on National Infrastructure for a Sustainable, Resilient Net Zero Future

All aspects of Modern life are infrastructure-enabled. National infrastructure (NI) simultaneously: supports the realisation of societally beneficial outcomes; and determines the level of GHG emissions; air, water, noise pollution; production of solid waste and sewage. Therefore, all sustainability and resilience challenges are interdependent emergent properties arising directly or indirectly from National Infrastructure. NI is a systemically, societally, economically, globally significant leverage point. The systemic transformation of NI into a net zero enabling, resilience enhancing, sustainability supporting system is urgently needed to catalyse the speed, scale and breadth of synergistic action needed to achieve Net zero and tackle other sustainability and resilience challenges. Systemic perspectives on, and systemic characterisations of, NI; its societal purpose; and the interdependent mechanisms that enable NI to fulfil its purpose are needed to support the required systemic transformation. This paper provides these.

Modeling for estimating and optimizing the energy potential of animal manure and sewage in small and medium-sized farms

The use and production of energy have a significant impact on the environment, including emissions of greenhouse gases into the atmosphere. Most of the energy consumed in the world comes mainly from fossil fuel sources. In this way, international public policy agendas have been encouraging the replacement of this energy source by renewable energy sources. The energy reuse of waste can contribute to the greater energy security through diversification of the energy matrix. Thus, the objective of this study was to develop a mathematical model capable of estimating and optimizing the allocation of energy potential, from animals manure and sewage. To achieve this objective, a deterministic constructive algorithm coupled with nonlinear model parameters was implemented. Data used for waste and sewage production were collected in farms of municipality in the state of Minas Gerais, Brazil. As a result of the calculations, a total energy potential of 1913 GWh y−1. On average, the properties taken into account in the study resulted in an estimated energy potential of 17,236.20 ± 55,137.63 kWh y−2; and those that did not have minimum potential, which economically enables the implantation of a local biogas plant, the potentials were allocated to the plants that serve a community. The average potential per plant varied between 36,792 and 54,663 kWh y−1 due to the 16 combinations between mathematical models and cases of financial analysis. A number between 35 and 52 corresponds to the number of plants that were allocated in the study municipalities and the average number of farms per plant ranged from 2.13 to 3.17. A model was adjusted to predict 92.4% of the variation in generation potential as a function of electricity consumption and farm production profit. Finally, it was validated that the perpestive of investment in renewable energy by a rural producer is dependent on the knowledge he has on the subject and on what he consumes on his property. The mathematical modeling to represent the optimization problem was implemented in a generic way, so it is capable of being applied to other energy systems, being able to point out good solutions considering environmental and financial issues. The results showed a robust, efficient, and adaptable model.

Occurrence of SARS-CoV-2 in excreta, sewage, and environment: epidemiological significance and potential risks

ABSTRACT The detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in patients’ excreta raises the issue of its occurrence and fate in sewage. This review has focused on the presence of the SARS-CoV-2 in human excreta, wastewater, sewage sludge, and river waters. It explored the potential use of the wastewater-based epidemiology approach to report on the situation of current and eventual future SARS-CoV-2 outbreaks. The main concern of the occurrence of SARS-CoV-2 in the environment is the public health risks at sites of sewage products disposal and reuse, especially in low-income countries with inadequate sanitation, where direct discharge and reuse of raw sewage are common practices. The review also addressed the role sewage-irrigated agriculture can have in SARS-CoV-2 spread in the environmental compartments reached through sewage products application. An overview was made on the interest of sewage management, water safety, and hygienic practices for controlling the environmental dissemination of SARS-CoV-2.