Urban Solid Waste Research Articles

Water Quality Assessment in an Area Degraded by Urban Solid Waste in Southern Brazil

ABSTRACTIn most Brazilian municipalities, urban solid waste (USW) is disposed of in open dumps, with numerous sites now being closed, monitored, and rehabilitated. One location, the “old dump” area in the Portão municipality (southern Brazil), previously served as an irregular repository for USW and industrial solid waste (ISW). Its use continued until 1993 when it was closed for a natural remediation process. For this reason, this study aimed to assess groundwater quality in the Portão “old dump,” employing physicochemical, microbiological, and toxicity quality indicators. The study's scope was extended to encompass the Portão Stream as well. Notably, the second collection campaign revealed elevated dissolved aluminum (Al3+), iron (Fe2+), and nitrate levels in all groundwater samples (from PZi wells, i = 1–6), with the PZ3 monitoring well experiencing the most pronounced impact. Further quality indicators, such as total phosphorus, thermotolerant coliforms, BOD5, as well as Al3+ and copper (Cu2+) levels in the second water collection campaign from Portão Stream, were classified as Class 4, suggesting that the water is suitable only for navigation and aesthetic purposes. Conductivity analysis identified Portão Stream as another impacted area. Moreover, during the second collection campaign, the study uncovered an escalation in micronuclei (MN) frequency and chromosomal alterations in PZ5. Downstream water samples from Portão Stream exhibited similarly heightened MN levels. This study's investigation into water quality is a concrete example of the implications of improper USW management. These findings underscore the pressing need for effective waste management strategies to mitigate environmental degradation and protect public health.

Environmental Sustainability and Solid Waste Management Procedures in Bukavu City, Democratic Republic of Congo

Environmental sustainability approaches such as effective solid waste management processes are indispensable for promoting sustainable urban development. Therefore, sustainable approaches to urban solid waste management are essential for every growing city. Bukavu City in Democratic Republic of Congo is a continuously growing city with a correspondingly increasing generation of solid waste which needs effective and sustainable management. This study engaged a mixed method model of both qualitative and quantitative approaches in assessing the perception of respondents on the sustainable aspect of the solid waste management procedures in the city of Bukavu. It administered 400 household questionnaires to residents, but also complemented the retrieved by interviewing key informants about the solid waste management approaches in the city. Results indicate inadequacy in the solid waste management processes in Bukavu City. Therefore, an inclusive and all-encompassing sustainable urban governance is proposed to encourage effective community participation in the management of the city environmental parameters alongside the enshrinement of a sustainable waste and environmental policy.

A corrigendum for article: Characterization of urban organic solid waste compost from six districts of the Leoncio Prado province, Peru

Ríos-Velasquez, E.A.; Florida-Rofner, N.; Lama-Isminio, D.A. 2023. Caracterización de compost de residuos sólidos orgánicos urbanos de seis distritos de la provincia Leoncio Prado, Perú. Rev. U.D.C.A Act. & Div. Cient. 26(1):e2371. http://doi.org/10.31910/rudca.v26.n1.2023.2371. Cuando se publicó el artículo señalado arriba, el autor de correspondencia Nelino Florida Rofner incluyó a Demetrio Angelo Lama Isminio. Sin embargo, Demetrio Lama solicitó a la Revista U.D.C.A Actualidad & Divulgación Científica su retiro de la publicación por no participar activamente en el desarrollo del trabajo y no ser su campo de experticia. La solicitud fue atendida por la revista y consultada con Nelino Florida Rofner, quien estuvo de acuerdo con el retiro de Demetrio Angelo Lama Ismino de la publicación. El cuerpo editorial de la revista aclara que, con base en la evaluación de los pares y el proceso editorial, se considera que los datos presentados en el artículo no pierden validez con esta acción. Además del retiro de Demetrio Angelo Lama Isminio del documento, se cambió el apartado de contribución de los autores que inicialmente se publicó de la siguiente manera: Contribución autores: Emilio Anthony Ríos-Velásquez y Demetrio Angelo Lama-Isminio realizaron los trabajos de campo, obtención y análisis formal de los datos para la escritura del borrador del manuscrito. Nelino Florida Rofner contribuyó con la asesoría de la investigación, la contextualización, la metodología, revisión y redacción del manuscrito. Todos los autores participaron en la redacción, revisión, edición del manuscrito y aprueban la versión final. Nelino Florida Rofner y el cuerpo editorial de la Revista U.D.C.A Actualidad & Divulgación Científica piden disculpas por este error.

Analysis of the Gravimetric Composition of Urban Solid Waste from the Municipality of Belém/PA

This article aimed to evaluate, using statistical tools, the generation and composition of municipal solid waste (MSW) in the city of Belém, Pará, from nine urban collection sectors in the municipality and the average nominal income of the population. Approximately 900 kg of urban solid waste was collected from the municipality in the period from 2021 to 2022. Statistical tests were carried out on hypotheses with 5% significance in comparative evaluations and their respective average nominal incomes. The results indicated that the organic fraction corresponded to 55.57% of the waste generated in the municipality, 14.26% was inert waste (potentially contaminating), and 0.67% was miscellaneous waste. It was observed that the waste generated by families with high purchasing power tended to contain higher percentages of recyclables while in families with lower purchasing power, the highest percentages tended to be organic. Knowledge of the generation of MSW is fundamental for the choice and dimensioning of operations and processes involved in the management chain at the municipal level. The decentralization of services offered based on solid waste management would enable greater success in serving the population.

Application of system dynamics to evaluate reduction targets for the entry of solid waste into a landfill site

The waste produced around the world increases daily due to population increase and the fact that life expectancy is longer. Waste production is higher in urban environments; therefore, managing Urban Solid Waste must be more rigorous to avoid environmental problems and health effects. For this reason, standards are created to properly manage landfills so that each life cycle stage is managed responsibly. However, a solid commitment from the community and more management regulations from the government are needed to be focused on reducing, reusing, and recycling materials as much as possible. This commitment needs to be reinforced to the extent that regulatory policies are created at the household level as much as education and awareness programs are implemented. This study presents a method to evaluate how imposing waste management goals before they reach landfills can increase the lifetime of landfills and, consequently the suitableness of a treatment plant implementation.

What do Contemporary Publications Report about the Generation of Urban Solid Waste (MSW) and/or Consumption from the Perspective of Chemistry Teaching?

The present study aimed to highlight the research on the topics of urban solid waste generation and consumerism from the perspective of Chemistry teaching between the years 2018 and 2023. To this end, a State-of-the-Art research, according to Romanowski and Ens (2006), in Periódicos Capes database on the aforementioned themes was realized. The methodology used was qualitative. The forms of analysis applied were both mediated by the IRAMuTeQ software and processed by the content analysis of Bardin (2002). In relation to the survey in Periódicos Capes, a textual corpus was obtained with 15 article summaries. Still as results, for textual statistics, the emergence of 82 text segments (ST) was observed, with the use of 65 ST (79.3%) and six classes in the Descending Hierarchical Classification (DHC). This is a satisfactory use and allows us to classify this analysis as consistent and consequently move on to content analysis based on the DHC. The mottos Waste and Generation were the highlights of the similarity analysis, preceded by the mottos Technology, Environmental, Student and Consumerism. In relation to content analysis, two very important categories emerged that communicate well with this object of study. As a consideration, it appears that in the contemporaneity of the last five years, there are strong signs of gaps regarding the use of these themes in the teaching of Chemistry, making it important for researchers to invest more time in the development of the area.

Food waste impact on dry anaerobic digestion of straw in a novel reactor: Biogas yield, stability, and hydrolysis-methanogenesis processes

Gradient anaerobic digestion reactor (GADR) can improve substrate utilization efficiency by solving the problem of the “short circuit” of materials. However, the substrate’s composition significantly affects the reactor’s performance. This study investigated the impact of food waste (FW) levels on corn straw’s dry anaerobic digestion (AD) in a novel GADR. The results show that biomethane production can be improved by coupling urban and agricultural solid waste recycling. The mechanism is to increase the hydrolysis and acid production efficiency, and the abundance of enzymes related to methanogenesis. The maximum methane yield (494.2 mL CH4/g VS) and the highest anaerobic biodegradability (85.7 %) were obtained when the FW was added at 60 %. The co-digestion of FW and straw can improve the hydrolysis and acid production efficiency and methane yield, which improves the buffering capacity and stability of the system compared with the single digestion of FW.

INVESTIGATION OF WASTE KUZNETS CURVE HYPOTHESIS IN SELECTED OECD MEMBER EU COUNTRIES: PANEL DATA ANALYSIS

Waste generation and composition are crucial aspects of environmental sustainability. Recently, they have gained attention from researchers due to their close association with social and environmental issues. The objective of this study is to assess the validity of the Waste Kuznets Curve (WKC) hypothesis about urban solid waste production in the top ten countries with the highest urban solid waste generation among the OECD member EU countries. The study analyses the impact of socio-economic control variables on per capita urban solid waste generation. A panel regression model was used for the sample group of countries from 1995 to 2019, and predictions were made. WKC hypothesis, which suggests a negative relationship between per capita urban solid waste generation and per capita real income, was invalid based on the results. Furthermore, the inclusion of control variables such as the Human Development Index, population density, and unemployment rate had a significant impact on the generation of urban solid waste per capita. When the relevant literature is evaluated, it is envisaged that the study will contribute to the very limited literature in which the WKC hypothesis is tested in the model, in which socioeconomic variables are also taken into account, due to the specificity of the current period and the selected country group.

Effects of Fly Ash on the Efficiency and Bacterial Community Structure of Urban Multi-source Organic Solid Waste

To achieve efficient resource utilization of fly ash and multi-source organic waste, a composting experiment was carried out to investigate the effects of fly ash on co-aerobic composting using kitchens, chicken manure, and sawdust (15:5:2). The effects of different application doses (5 % and 10 %, calculated in total wet weight of organic solid waste) of fly ash on physical and chemical properties, nutrient elements, and bacterial community structure during co-composting were evaluated. The results showed that the addition dose of 5 % and 10 % fly ash significantly increased the highest temperature (56.6 ℃ and 56.9 ℃) and extended the thermophilic period to nine days. Compared with that in the control, the total nutrient content of compost products in the treatments of 5 % FA and 10 % FA was increased by 4.09 % and 13.55 %, respectively. The bacterial community structure changed greatly throughout the composting, and the bacterial diversity of all treatments increased obviously. In the initial stage of composting, Proteobacteria was the dominant phylum of bacteria, with a relative abundance ranging from 35.26 % to 39.40 %. In the thermophilic period, Firmicutes dominated; its relative abundance peaked at 52.46 % in the 5 % FA treatment and 67.72 % in the 10 % FA treatment. Bacillus and Thermobifida were the predominant groups in the thermophilic period of composting. The relative abundance of Bacillus and Thermobifida in the 5 % FA and 10 % FA treatments were 33.41 % and 62.89 %(Bacillus) and 33.06 % and 12.23 %(Thermobifida), respectively. The results of the redundancy analysis (RDA) revealed that different physicochemical indicators had varying degrees of influence on bacteria, with organic matter, pH, available phosphorus, and available potassium being the main environmental factors influencing bacterial community structure. In summary, the addition of fly ash promoted the harmlessness and maturation of co- aerobic composting of urban multi-source organic waste, while optimizing microbial community structure and improving the quality and efficiency of composting.

An Extensive Analysis of Combined Processes for Landfill Leachate Treatment

Sanitary landfilling is the predominant process for solid urban waste disposal, but it generates leachate that poses environmental, economic, and social concerns. Landfill leachate (LL) contains complex and refractory pollutants and toxic compounds that can vary depending on landfill maturity, age, and biochemical reactions, making its treatment challenging. Due to its unique characteristics and occurrence in remote locations, LL requires separate treatment from wastewater. Various conventional treatment processes involving biological, chemical, and physical processes have been used for LL treatment, but a single treatment process is insufficient to meet environmental standards. This review demonstrates that combined treatment processes are more effective and efficient for LL treatment compared to single processes. Among the various combinations, chemical–chemical and chemical–biological treatments are the most commonly used. Specifically, the integration of Fenton with adsorption and a membrane bioreactor (MBR) with nanofiltration (NF) processes shows promising results. The combined processes of MBR with NF, Fenton with adsorption, and PF with biological treatment show maximum removal efficiencies for COD, reaching 99 ± 1%, 99%, 98%, and 97%, respectively. Additionally, the combined Fenton with adsorption process and EC with SPF process enhance biodegradability as indicated by increased BOD5/COD ratios, from 0.084 to 0.82 and 0.35 to 0.75, respectively. The findings emphasize the importance of developing and implementing enhanced combined treatment processes for LL, with the aim of achieving efficient and comprehensive pollutant mineralization. Such processes have the potential to address the environmental concerns associated with LL and contribute to sustainable waste management practices.

Mini-Open Dumps in the Paraná River Floodplain: Local Problems with Global Effects.

The growing production of urban solid waste is a structural problem faced by most cities around the world. The proliferation of mini-open dumps (MOD; small spontaneous open-air waste dumps formed in urban and peri-urban areas) on the banks of the Paraná River is particularly evident. During the historical drought (June-December 2021), we carried out sampling campaigns identifying MODs of the Santa Fe River, a secondary channel of the Paraná River. MOD were geolocated, measured, described and classified by origin. The distance to the river and other sensitive places was considered (houses-schools-health facilities). Our results suggested a serious environmental issue associated with poor waste management. MOD were extremely abundant in the study area, being mostly composed of domestic litter. Plastics clearly dominated the MOD composition. Burning was frequently observed as a method to reduce the volume of MOD. We concluded that the proliferation of MOD is a multi-causal problem associated with a failure of public policies and a lack of environmental education.

EXPERIMENTAL STUDY ON PHYSICOCHEMICAL PROPERTIES OF COMPOST BY PARTIAL REPLACEMENT OF ORGANIC MATTER WITH DAIRY SLUDGE

Organic wastes are wastes that are easily biodegradable. These wastes are produced from many sources such as agricultural waste, market waste, kitchen waste, urban solid food wastes and municipal solid waste. The main objective of the present study is to decompose the organic matter along with dairy sludge with different ratios through the Aerobic composting process, analyze the various controlling parameters during the process, test the physicochemical parameters of finished compost and compare it with the standards prescribed by AP Horticulture Department and to pick optimum dairy sludge and vegetative matter ratio and the benefits of this project were also discussed. In this study dairy sludge along with organic matter in four different ratios like 100% vegetative matter,40:60, 50:50, 60:40 was mixed for 15 days and allowed to decomposed for 45 more days and the finished compost physicochemical parameters were analyzed. Results from this study were compared with standards set for compost by AP horticulture department and the results of this study have met Standards fixed by Horticulture department. Although all the compost samples satisfied the required standards fixed by AP Horticulture department in terms of all physicochemical parameters sample 3 is found to best with dairy sludge to vegetative matter ratio of 50:50 was found to be best with Moisture content 20.91%, pH 7.4, EC 3.5dsm-1, Organic Carbon 22%, Nitrogen 1.6%, Phosphorus 0.78%, Potassium 0.91%, C:N ratio 13.75:1, Zinc 67.8 ppm, Iron 1420 ppm, Copper 14.20 ppm, and Manganese 31 ppm. In Sangam dairy an average of 600 KLD Wastewater was treated per day with assumed consistency of sludge as 1% and 120 mg/L suspended solids present in Wastewater and thereby leading to annual generation of 1248 ton of compost which generates an annual revenue of 62,40,000/- and an annual profit of about 50 lakhs excluding construction operation and maintenance costs. Key Words: biodegradable, Wastewater, compost, sludge

Challenges in municipal solid waste management-A comparative case study between selected metropolitan areas Brazil and Portugal

This research was aimed at analysing the management of urban solid waste in Brazil and Portugal, with an emphasis on the metropolitan areas of Lisbon and Porto and the Recife/PE/Brazil Metropolitan Area. An exploratory research project was conducted with a survey of secondary data, technical visits to institutions and companies in the waste sector, and a comparative analysis of the situation in the areas studied. In Portugal, the management of municipal solid waste in the period before 1995 was predominantly municipal, which evolved into a consortium of municipalities with the entry of Portugal into the European Union in 1986. The country adapted its legislation to the EU Directives, and from 1997, the waste sector suffered a boost with the adoption of the first Strategic Plan for Urban Solid Waste, which was constituted by 40 public waste management companies that associated several municipalities, and some of them also had the state's share in their share capital. However, due to the lack of economic scale of some of these companies, there were mergers, and at the end of 2010, the total number of companies was 23, grouped into entities of a multi-municipal character (when the state enters into the composition of the share capital of the society) and inter-municipal (only constituted by municipalities), currently responsible for the management of waste in Portugal. In Brazil, the National Solid Waste Policy was approved by law in 2010, establishing lines and guidelines for integrated waste management with defined time targets. However, it is not yet fully implemented because about 45% of municipalities still dispose of waste at dumping sites. With regard to the municipalities of the Recife Metropolitan Area, the disposal of waste has already been environmentally appropriate since 2019. According to 2022 data from Brazilian Association of Public Cleaning and Special Waste Companies, the average rate of selective collection in the country is approximately 4%. The research results reveal that Brazil needs to increase selective collection, eliminate approximately 3,600 existing landfills and finally regulate urban solid waste services. While in Portugal, management is well organized as a result of the implementation of PERSU in 1995, there are still challenges to be overcome in order to meet the goals set in the New Legislative Framework, which have not yet been achieved. The specificities and the context are obviously different between the countries, drawing attention to the difference in effectiveness in the implementation of public policies edited by the legal diplomas of the two countries for solid waste management.

Analisis Produktivitas Alat Berat dalam Pengelolaan Sampah di Kecamatan Sukarami Kota Palembang

In Indonesia, solid waste has become a problem for municipalities, which could result in hygienic and aesthetically unpleasant issues. The high rate of population growth will have an impact on waste generation since it will change the needs and lifestyles of city dwellers. The collection, transportation, and final disposal of urban solid waste (TPA) require suitable facilities and infrastructure, particularly hefty equipment. Heavy equipment, specifically waste trucks, and heavy digging equipment, plays a significant part in supporting waste management activities. In particular, the Palembang City region is covered in this study's discussion of the productivity of heavy machinery used in waste management, which might begin with the collecting system, transportation system, and heavy equipment employed at the landfill. The study was conducted in Palembang City's Sukarami District, and data was collected by surveying and observing the current condition of the heavy equipment that was already in place, namely in terms of cycle time variables and the volume of waste that was served. The findings of the study indicate that direct communal and direct individual patterns characterize the region's waste-collecting practices. Dump trucks, which are used to transport waste, had a productivity range of 609.98 to 1266.13 kilograms per hour, while bulldozers and excavators had a range of 759.42 to 1166.17 kilograms per hour. This heavy equipment repair recommendation is targeted at bulldozers and excavators since a field investigation reveals that there are now only 2 pieces of bulldozer heavy equipment and 1 unit of excavator heavy equipment available.

Identification of potential landfill site suitability for urban solid waste disposal of Balurghat Municipality of Dakshin Dinajpur District using GIS and multi-criteria decision-making approach

The production of urban solid waste is one of the most dangerous environmental health risks on the planet. By selecting suitable landfill sites, it is possible to resolve the issue of health risks and environmental pollution driven by the unscientific disposal of solid waste. The current research is centered on determining suitable landfill locations for solid waste disposal within the Balurghat municipality through the integration of Geographic Information System (GIS) and Multi-Criteria Decision-Making (MCDM) approach. Ten factors were taken into consideration according to their weightage including elevation (0.022), Lithology (0.027), Slope (0.032), Land use and land cover LULC (0.040), Depth of water (0.057), Population density (0.075), Distance from sensitive places (0.107), Distance from road (0.154), Distance from river (0.205) and Land value (0.282). After conducting thorough field visits, an analytical hierarchy process (AHP) under the MCDM approach using GIS reveals acceptable sites that were noted and referenced. Final results are validated through a receiver operating characteristic (ROC) curve using randomly selected 80 potential landfill-suitable site location points with higher accuracy, and a total of 93% of the area under the curve (AUC) has been found worthy to validate the spatial result. The present investigation revealed that only 0.65% of land is very highly suitable, 31.06% of land is highly suitable, 52.54% of land is moderately suitable and 14.74% of land is not suitable for landfilling in Balurghat Municipal area and surroundings respectively. The highly suitable site belongs to the Mamna, Katna, Kuaran, Amtali, Noksha, Bannapara, and Malancha villages of the study area which is a very negligible area. So, the planners should adopt alternative strategies like source minimization, composting, sanitary landfills and awareness programmes for sustainable solid waste management. Hence, the Balurghat Municipality administration, urban planners, and administrative authorities stand to gain valuable insights from the findings of this study as they endeavour to enhance the management of urban solid waste in the area.

Feasibility of Using Recycled Materials in Construction Materials

The increasing amount of solid waste has become a significant environmental issue that has garnered significant attention and concern. In an effort to mitigate the adverse effects commonly associated with prominent sectors and simultaneously promote credibility in the energy- and resource-intensive realms of development and construction, significant endeavors have been directed towards competitive areas of strength for the purpose of recycling, with the ultimate goal of utilizing such materials in sustainable development products. The present study provides an overview of the ongoing evaluations pertaining to the utilization of conventional and enhanced solid waste for the production of geo-polymer composites. Great attention is devoted to the implementation of these geo-polymer composites. The primary findings of this study revealed that both ordinary and sophisticated solid waste have the potential to be integrated into geo-polymer composites in various forms, such as precursor, complete, additive, reinforcement fiber, or filler material. The findings indicate that the utilization of such waste may have a negative impact on certain properties of geo-polymer composites. However, this issue can be mitigated through the implementation of an open degree plan and appropriate treatment techniques, which can facilitate the recycling process. In conclusion, a concise discourse is presented to acknowledge the significant need for future research and enhancement in advancing the utilization of solid waste materials in the emerging sustainable geo-polymer industry. This study proposes an improved ecological solution for managing municipal and industrial solid waste by transforming waste materials into environmentally friendly construction materials with consistent properties. Special attention is given to the overall performance of geo-polymer composite products. The primary findings of this study reveal that urban and industrial solid waste can be efficiently incorporated into geo-polymer composites through the use of precursors, aggregates, additives, reinforcing fibers, or filler materials. The results indicate that while the inclusion of waste materials may negatively impact certain properties of geo-polymer composites, a well-designed protocol and effective treatment approach can mitigate these adverse effects and facilitate the recycling process. Finally, a brief dialogue is presented to differentiate the key needs in forthcoming research and development aimed at enhancing the utilization of solid waste materials in the upcoming sustainable geopolymer sector. This study provides guidance for the sustainable management of urban waste by transforming waste materials into environmentally friendly construction materials.

Occurrence, source apportionment and ecological risk of bisphenol analogues in river sediments in areas with different land use patterns

Bisphenol analogues (BPs) have gained increasing attention in recent years due to their ubiquitousness and potential endocrine disrupting properties in environments. However, little information is available on their spatiotemporal distribution, source apportionment and ecological risk in river sediments, especially the case in river basins with a high population density and those typical regions with agricultural-urban gradient, where land use patterns and intensity of human activity are varying. In this study, field investigations of BPs in the sediment of the entire Qinhuai River Basin, a typical agricultural-suburban agricultural-urban gradient area, were conducted before and after the flood period. Thirty-two sites were sampled for six types of BPs, resulted in no significant difference in the concentration of ΣBPs between the two periods, with ΣBPs ranging from 3.92 to 151 ng/g and 2.16–59.0 ng/g, respectively. Bisphenol A (BPA) was the main contributor. Whereas a multivariate analysis of variance (MANOVA) suggested that the composition structure of BPs had been influenced by water periods. The land use patterns had an impact on the distribution of ΣBPs in river sediments, which was more significant in after the flood period, with ΣBPs in urban rivers was 1.85 times, 3.44 times, and 3.08 times higher than the suburban rivers, agricultural rivers, and reservoirs, respectively. Yet land use types did not significantly alter the composition structure of BPs. The correlation analysis between BPs and the physicochemical properties of sediments showed a significant positive correlation between BPA and total organic carbon (TOC). The positive matrix factorization model (PMF) suggested that BPs in sediments of the basin might be influenced by industrial coatings, textiles, electronics and biopharmaceuticals, as well as urban wastewater or solid waste generated from daily life. The ecological risk assessment posed by BPA, based on the risk quotient, indicated that the ecological risk of BPA in sediments was low for three indicator benthic organisms: crustaceans, worms, and mollusks. However, the risk of BPA in river sediments varied among different land use patterns, with the risk ranking as follows: reservoirs < agricultural rivers < suburban rivers < urban rivers.

Design of experiments to evaluate pH and temperature parameters with different inoculums in domestic biodigester

The comprehensive management of organic urban solid waste is a concern due to its direct and indirect impact on the environment. Anaerobic Digestion (AD) has been recognized as an alternative and environmentally friendly technology for waste disposal, converting them into organic fertilizers and renewable energy. This research presents an experiment involving four reactors fed with household organic waste, three inoculated with canine, goat, and rabbit manure, and one without inoculum. The experiment was observed for 30 consecutive days to analyze the pH and temperature parameters involved in the AD process in domestic reactors. Statistical methodology, including one-way analysis of variance for assessing the effect of the type of inoculum, Tukey's simultaneous confidence intervals for mean differences, and 90 % confidence intervals for μ in temperature and manure, was utilized. Additionally, main effects analysis of the factors of average temperature and pH were conducted. The results of the one-factor experiment show that the type of inoculum does not significantly influence the variation in pH, while temperature remains relatively stable throughout the AD process. However, the analysis of main effects indicates that goat manure tends to stabilize the temperature with minimal variation, whereas variation is more heterogeneous in the other experiments.

Eficiencia en la gestión de residuos sólidos urbanos en los municipios distritales de la macrorregión sur del Perú

The central objective of this study is to analyze the level of efficiency in the management of urban solid waste in the district municipalities of the southern macroregion of Peru in the year 2022 and how it is affected by different variables and management strategies. For this, information from the National Registry of Municipalities (RENAMU) for the year 2022 prepared by the INEI was used. The hypothetical-deductive method was used with a quantitative approach through an envelopment analysis model that allowed estimating the level of efficiency of the 174 urban district municipalities. Subsequently, a Tobit model was estimated to find how the management instruments affect the level of efficiency of the municipalities. It is concluded that some districts operate with high efficiency in solid waste management, such as Machupicchu, Pichari, Juli, while others have room to use their resources efficiently, such as Potoni, Cabanillas and Quilcapuncu. Furthermore, it was found that municipalities with greater efficiency manage to collect a greater amount of solid waste per capita and a higher level of waste collection coverage with similar resources to those inefficient municipalities. On the other hand, the implementation of waste management plans, urban development plans and institutional strategies are positively and significantly related to the level of efficiency.

Evaluation of the Dark Fermentation Process as an Alternative for the Energy Valorization of the Organic Fraction of Municipal Solid Waste (OFMSW) for Bogotá, Colombia

In the context of valorizing the organic fraction of urban solid waste (OFMSW) in megacities, dark fermentation emerges as a central strategy alongside composting and anaerobic digestion. This article focuses on assessing the environmental, technical, and energy viability of dark fermentation using life cycle assessment (LCA) and circular economy principles. Dark fermentation for biohydrogen production is an active and promising research field in the quest for sustainable biofuels. In this context, defining operational parameters such as organic loading and the substrate-inoculum ratio is relevant for achieving better production yields. Laboratory tests were conducted using organic loading values of 5, 10, and 15 g of volatile solids per liter (gVS/L) and with substrate-inoculum ratios (s/x) of 1, 0.75, and 0.5 g of volatile solids of substrate per gram of volatile solids of inoculum (gVSs/gVSi). The combination with the best performance turned out to be an initial organic loading of 10 gVS/L and an s/x of 1 gVSs/gVSi. From this result, it was determined that the s/x had a greater impact on production. Finally, a valorization plant was dimensioned with the scaled-up process, starting from the municipal solid waste generated by Bogotá projected for 2042. The scaling was demonstrated to be energetically sustainable, producing a power of 2,368,358.72 kWh per day.