Solid Waste Generation and Composition in Mexico： A Comparison between Rural and Urban Communities

This paper reports a generation and composition analysis of household solid waste in Mexico, using as a reference the characterization study performed in two communities, one urban and one rural. Data obtained are fundamental parameters for the planning of urban solid waste management systems in Mexico, complying this way with the established policy in the National Program for Waste Management and Prevention 2009-2012. The study was carried out during five days and two main parameters were assessed： （1） the daily generation rate per person and （2） the waste composition. The per capita waste generation was 0.958 kg for the urban community and 0.631 kg for the rural. The results showed that the mean composition of waste from both locations was statistically similar （a = 0.05）. In both locations the most important contribution was the fraction of food waste. In both locations more than 60% of the waste is potentially recyclable. The results of this study will be used by the municipal waste authorities in order to establish an integrated waste management plan.

Study on textile waste generation in the undifferentiated municipal solid waste stream in Guimarães,Portugal

Guimarães is a middle sized city and municipality located in northern Portugal.The municipality has committed to reducing the annual amount of undifferentiated municipal solid waste(MSW)from 371 kg/capita in 2021 to 120 kg/capita by 2030 under the Zero Waste Cities Certification process.In the municipality of Guimarães,one of the constant fractions of MSW composition is textile waste(TW),which the revised EU Waste Framework Directive requires separate collection by 1 January 2025.Therefore,two indicators of TW generation were analysed to identify waste collection routes with a high level of textile waste generation for the priority implementation of separate collection:TW composition in the undifferentiated MSW stream and TW generation per capita.Basic statistical analysis methods were used to process the source data of TW composition in the undifferentiated MSW stream.Cluster analysis was applied to the data set on TW generation per capita,considering the area typology(urban,rural or mixed)of collection routes.It was considered that 39%of the industrial sector of Guimarães consists of textile and clothing production and represents small-and medium-sized enterprises,which can affect TW generation in the undifferentiated MSW stream.Causal-comparative research was used to define the correlation between TW generation per capita and the economic activity of the textile and clothing industry in the municipality.As a result,applying a multi-disciplinary approach,a project of the Textile Waste Generation Map was presented.

Current Situation Analysis and Suggestions for Solid Waste Management Practices among Households in Freetown

Freetown which is the capital city of Sierra Leone is facing challenges with population growth, urbanization, and industrialization, leading to an increase in municipal solid waste (MSW) generation. The study aims to evaluate MSW generation, composition, and disposal methods, as well as the impact of collection fees, policy implementation, and women’s participation in municipal solid waste management (MSWM). The study used both qualitative and quantitative methods for data collection and analysis. The study administered 393 structured questionnaires in three selected sections to collect data on variables such as family size, education, level of knowledge, etc. The study used door-to-door data collection to determine the rate of solid waste generation, composition, and disposal in 66 households from two of the selected sections and 34 households from the other section to evaluate the current situation of MSWM practices among households in Freetown. The study used a descriptive statistic to analyze the data collected using Origin-Pro9 and MS Excel software. The findings showed that with a 4.2% urban growth rate, Freetown had a population of 1,467,543 in 2023, generating 851 tons of MSW per day, with organic waste accounting for 78% of the total MSW generated. Plastic waste generation also increased from 7.6% in 2020 to 13% in 2023. The study emphasizes the need to sustain the MSWM system by prioritizing solid waste collection fees, policy enforcement, and women’s participation in the MSWM sector. It further suggests and provides recommendations for developing an efficient and sustainable MSWM system in Sierra Leone, including knowledge transfer from countries like China and the US.

Application of Multivariate Reinforcement Learning Engine in Optimizing the Power Generation Process of Domestic Waste Incineration

Garbage incineration is an ideal method for the harmless and resource-oriented treatment of urban domestic waste.However,current domestic waste incineration power plants often face challenges related to maintaining consistent steam production and high operational costs.This article capitalizes on the technical advantages of big data artificial intelligence,optimizing the power generation process of domestic waste incineration as the entry point,and adopts four main engine modules of Alibaba Cloud reinforcement learning algorithm engine,operating parameter prediction engine,anomaly recognition engine,and video visual recognition algorithm engine.The reinforcement learning algorithm extracts the operational parameters of each incinerator to obtain a control benchmark.Through the operating parameter prediction algorithm,prediction models for drum pressure,primary steam flow,NOx,SO2,and HCl are constructed to achieve short-term prediction of operational parameters,ultimately improving control performance.The anomaly recognition algorithm develops a thickness identification model for the material layer in the drying section,allowing for rapid and effective assessment of feed material thickness to ensure uniformity control.Meanwhile,the visual recognition algorithm identifies flame images and assesses the combustion status and location of the combustion fire line within the furnace.This real-time understanding of furnace flame combustion conditions guides adjustments to the grate and air volume.Integrating AI technology into the waste incineration sector empowers the environmental protection industry with the potential to leverage big data.This development holds practical significance in optimizing the harmless and resource-oriented treatment of urban domestic waste,reducing operational costs,and increasing efficiency.

Generation, Characterization and Management Practices of Household Solid Wastes in Cowfield, Paynesville City, Liberia

The success of any waste management system requires accurate and up-to-date data on quantity, composition of waste. Waste generation data from household are needed to address issues relating to municipal solid wastes such as management method, performance improvement, policy, regional and local planning, administrative, cost accounting, design and operation of landfill facilities and environmental quality. This study was conducted to provide empirical data on generation rates, quantity and composition, management practices, challenges and strategies from urban household. Waste collection, weighing, questionnaires survey and field observation were methods used during the study. Waste was collected and weighed from 60 households using multi-stage sampling technique for seven days. Questionnaires were analyzed using Statistical Package for Social Sciences version 20 and Excel. A total of 1125.2 kg of waste was recorded. The average household waste generation was 3 kg per day with per capita generation rate of 0.41 kg/cap/day. The compositional analysis showed that Organic (53%), Plastic (11%), Textile (6%), Metal (2%), Glass (1%), Paper and Cardboard 4% and others (22%). Solid waste management practices are very rudimentary. Burning (53.7%) and Open Dumping (30%) were found to be the most commonly used method of disposal with very limited collection service (33.3%) and segregation. The most challenges faced by households were communal disposal area (66.7%) and waste service providers (21.7%) storage bins (11.6%). Waste to energy (48.3%) and compositing (23.3%) were the most considered option for waste management by the respondents.

Lagos State Hospital Waste Management Practices: A Descriptive Overview with Stakeholders’ Role and Key Recommendations

Background: Waste generation and its disposal is an essential issue in the sustainability of the environment and the planet’s future. Waste management is essential across sectors, likewise the health sector. Therefore, there is a need to employ extra care and attention to handling waste generated from healthcare facilities to avoid the dangers of poor biomedical waste management. We carried out this study to examine the waste management practice in healthcare facilities in Lagos State. Methods: The study was a descriptive survey carried out in one-thousand two hundred and fifty-six (1256) healthcare facilities in Lagos State. Nine hundred sixty-nine (969) of these facilities are located in urban areas, while two hundred and eighty-seven (287) are rural. The facilities studied are government/public health facilities (15.45%), private-for-profit facilities (82.88%), NGOs, Mission/Faith-Based medical facilities (1.67%). The data collected were analyzed using descriptive statistics. Specifically, we utilized bar charts, frequency, and percentage. Result: The result shows that 98.4% (1236) of the studied facilities are registered with the Lagos State Waste Management Authority (LAWMA), while 1.6% (20) are not registered. 98.5% (191) of the 194 government-owned facilities, 98.5% (1025) of the 1041 private-for-profit facilities, and 98.2% (20) of the 21 NGOs/faith-based health facilities are registered with Lagos State Waste Management Authority. The result also shows that 94% of the healthcare facilities studied in Lagos State use color-coded waste bags to segregate waste at the point of origin. 58.7% of the facilities use red-colored bags, 33.3% use yellow-colored bags, 10.7% use black-colored bags, and 1.3% use brown biohazard bags for segregating Infectious waste. Also, 34.2% of the health facilities in Lagos state use red-colored bags, 36.9% use yellow-colored bags, 11% use black-colored bags, and 4.1% use brown-colored bags to segregate their hazardous waste. Conclusion: Some healthcare facilities in Lagos State do not follow the recommended guidelines for medical waste segregation. Waste generated is not appropriately segregated at the point of origin into the recommended colored bags/bins in some facilities. Thus, a policy and procedure regulating healthcare waste are mandatory. It is important to regularly train healthcare workers on proper waste management practices and encourage staff to read and apply WHO rules in managing healthcare waste. Healthcare personnel should realize that hazardous material is a potential cause of a public disaster.

Comment on the development and policy of the waste incineration power generation industry

Development space of the waste incineration power generation is expanding. According to the technical route of previous planning and related policies, the principles of our garbage disposal are based on sanitary landfill, supplemented by burning. However, with the accelerated process of urbanization, land resources are increasingly strained and most large cities have been unable to find a suitable landfill within the feasible urban extent, the main equipment for the incinerator and the localization of the overall process greatly reduced its capital investment and these factors will promote the rapid development of waste incineration power generation industry. Waste incineration and power generation technology has the dual benefits of environmental protection and energy and it is the development direction of waste disposal in the future. According to the condition that our country＇s waste incineration power generation started from scratch and developed rapidly in recent years ,there is a introduction about the application of the waste incineration and a brief analysis of the its obstacles in the promotion and financing, as well as the potential for future applications.

Efficiency analysis of trilateral-cycle power systems for waste heat recovery-to-power generation

Numerous innovative heat recovery-to-power technologies have been resourcefully and technologically exploited to bridge the growing gap between energy needs and its sustainable and affordable supply.Among them,the proposed trilateral-cycle(TLC) power system exhibits high thermodynamic efficiency during heat recovery-to-power from low-to-medium temperature heat sources.The TLCs are proposed and analysed using n-pentane as working fluid for waste heat recovery-to-power generation from low-grade heat source to evaluate the thermodynamic efficiency of the cycles.Four different single stage TLC configurations with distinct working principles are modelled thermodynamically using engineering equation solver.Based on the thermodynamic framework,thermodynamic performance simulation and efficiency analysis of the cycles as well as the exergy efficiencies of the heating and condensing processes are carried out and compared in their efficiency.The results show that the simple TLC,recuperated TLC,reheat TLC and regenerative TLC operating at subcritical conditions with cycle high temperature of 473 K can attain thermal efficiencies of 21.97%,23.91%,22.07% and 22.9%,respectively.The recuperated TLC attains the highest thermodynamic efficiency at the cycle high temperature because of its lowest exergy destruction rates in the heat exchanger and condenser.The efficiency analysis carried out would assist in guiding thermodynamic process development and thermal integration of the proposed cycles.

Comparative Study on Distributed Waste Pyrolysis Cold Emission Energy Station and Incineration Power Generation

The proper terminal disposal of organic solid waste such as domestic waste is a worldwide issue.Landfill covers a large area,with limited capacity,and a single landfill will be filled one day;incineration is costly to build and operate.These methods all need to transfer and centralized treatment,and secondary pollution is difficult to control,against the purification law of the nature."NIMBY effect"is very serious,and the social cost of treatment is increasing,becoming a heavy financial burden."The Distributed Waste Pyrolysis Cold Emission Energy Station"developed by Hunan Zhongzhou Energy-Saving Technology Co.,Ltd.overcomes these disadvantages and constructs a more appropriate environmental economic industrial chain for the treatment of organic solid waste such as urban and rural household waste.Based on its technical characteristics,this paper compares it with waste incineration power generation project in the aspects of secondary pollution control,treatment effect,energy utilization,investment and operation economy,etc.

Study on China＇s Policy Text for Municipal Solid Waster Power Generation

Chinese government has initiated many preferential policies for supporting the circular economy, including the industry of municipal solid waste （MSW） power generation. This paper collects relevant policies for China＇s MSW power generation. It also analyzes the overall environment of policies for the MSW power generation from three aspects---the basic principles for China to develop MSW power generation, the operating mechanism and the specific preferential policies. The analysis establishes foundation for further research toward policy integration.

Optimal Analysis of Pure Low-Temperature Waste Heat Recovery Generation System

In this paper, a detailed thermodynamic analysis of the pure low-temperature waste heat recovery generation system is presented. The parameters affecting the system performance are compared to obtain the most significant ones; furthermore, parameter values are optimized for the largest power generating capability of the system. It is found that the most important parameters are inlet flue gas temperature, steam pressure and the pinch point temperature difference. There is an optimal superheated steam pressure value for giving the maximum generation power per unit flue gas. With the increase of inlet flue gas temperature, the generating power increases and the optimized steam pressure rises as well. However, with increase in pinch point temperature difference, the generating power decreases and the optimized steam pressure decreases as well. The theoretical calculation provides a theoretical basis for the parameters optimization in the design of the pure low-temperature waste heat recovery eeneration swtem

Construction Waste Quantification and Benchmarking： A Study in Klang Valley, Malaysia

Construction industry is a major contributor of negative impact to the environment. Estimation of construction waste amount is crucial for implementing waste minimization program. Estimation of construction waste amount generated is a mean in assessing the potential for waste reduction. Decision-making should be based on quantified measurements expressed in numerical terms to effectively minimize waste produced. A better understanding of C＆D waste generation in terms of causes and sources can be achieved. Lack of benchmarking will hinder the implementation of more sustainable practices in the industry. The aim of this paper is to establish benchmarks on construction waste generation rate in Klang Valley （greater Kuala Lumpur）, Malaysia using appropriate waste quantification method. Nine projects in Klang Valley constructed between 2006-2010 have been selected for this study, which include residential and commercial building projects conducted by a wide range of contractors employing conventional and IBS systems. Wastage level and waste index approaches had been employed in this study as tools for quantifying waste and also for environmental assessment. Types of waste that generated at significant amount, such as concrete, timber, reinforcement bars, tiles, screeds, and plaster are considered. Other factors, such as waste management provision, Environmental Management System （EMS） employed, record-keeping, contractors＇ profile and other related policies are also assessed by conducting interviews with construction personnel. Based on the findings, overall site-management, size of project, and awareness of waste management among construction personnel are the most significant factors that contribute to construction waste generation. Currently, there is still relatively lack of waste minimization awareness among construction players in Malaysia as reflected by poor waste record-keeping, lack of waste sorting and recycling practice, low usage of IBS systems, and lack of supports from top management, clients, and authorities. The roles of construction authorities are essential in achieving the desired benchmark in waste generation rate for Malaysian context. Construction authorities as the policy maker and enforcer could develop and issue new regulations or incentives to stimulate and encourage waste management practices and the use of green building technology, establishing formally standardized systems in record-keeping of quantitative data, introduce useful guidelines and measures, conduct education and training to achieve sustainability and better environmental awareness among Malaysian construction players.

Exploration and Application Practice of Energy Conservation Theory and Method in Steel Manufacturing Process System

This article briefly discusses the theoretical basis and overall goals of energy conservation in the steel manufacturing process system.It is proposed that in the process of implementing system energy conservation,it is necessary to fully recognize and utilize the characteristics and functional advantages of the steel manufacturing process,pay more attention to energy quality,firmly grasp the overall goal of system optimization,focus on the integrated optimization of gas,steam,and waste heat systems,and propose the idea of constructing a"steel chemi-cal gas electricity heating cooling multi generation system".Based on practice,the main principles,models,and effects of implementing systematic energy conservation in steel enterprises have been proposed.

Analysis of Health Workers’ Perceptions on Medical Waste Management in Tanzanian Hospitals

This paper presents the perceptions of health workers (HWs) on medical waste management (MWM) issues in Tanzanian hospitals. The perceived total waste generation rates were lower than the actual measurements. Administrators perceived lower rates than implementers. The results indicated three categories of medical waste which are given due attention, that is, sharps waste, pathological and infectious waste. Other wastes like radioactive, chemical, pharmaceutical, pressurized containers receive very little attention. Container colour coding and labelling was negligible, while improvised containers are still in use. Medical waste is transported within hospitals manually, with little efforts on mechanized transportation. Poor waste storage was observed, while the prominent medical waste treatment technologies are medium temperature incinerators. Off-site transportation of medical waste is practiced, where the waste is finally dumped or buried. The hospitals are currently utilizing public-private partnership schemes for MWM in only one aspect of off-site transportation. Three main problems which require high attention include: Weaknesses in hospital management, poor MWM infrastructure, and lack of skills and knowledge on MWM among HWs. Knowledge and awareness among HWs on health hazards associated with poor MWM is low (with exception of cholera, HIV and typhoid). Few PPE types are supplied and used in the hospitals, leading to poor diseases prevention. There is also low knowledge among HWs on administrative issues related to MWM in Tanzanian hospitals.

Re-Use of Hospital Plastic Waste in Asphalt Mixes as Partial Replacement of Coarse Aggregate

About 1.3 billion tons of waste is being generated in the world annually. This waste is a cause of various diseases. Open dumping of waste also destroys valuable agricultural land. Various researchers have beneficially used plastic waste in cement concrete and asphalt concrete in the past. This study aims at the use of aggregates, made from different types of plastic waste, as partial replacement of coarse aggregates in asphalt mixes. For this purpose waste is collected from different hospitals of the city. Sorted plastic from the waste consists of 64% low density polyethene, 32% high density polyethene and 4% of polypropylene. Plastic waste is shredded, heated and after cooling, pulverizes manually and mechanically. Specific gravity of plastic aggregates is 0.96. Water absorption and soundness values are 4.68% and 7.68% respectively. Impact, crushing and Loss Angeles values of plastic aggregates are 0.7%, 0.5%, and 1.1% respectively. Replacement of natural aggregates by plastic aggregates in asphalt mixes is done up to 25% with 5% incremental increase. Density of asphalt mixes decreases to 2060 kg/m3. Consequently flow increases to 5.73 mm. Maximum stability is at 20% replacement i.e. 34.57 KN. Cost analysis of the study indicates that 205% increase in stability are observed with 219% increase in cost.

Diagnostic Analysis of Mechanical Conditions of Small-Scale Incinerators in the Healthcare Facilities in Tanzania

This paper provides analytical diagnosis of mechanical conditions of medical waste incinerators used for healthcare waste (HCW) treatment in Tanzania. The main features assessed were types of incinerators, features of incinerators and incinerator house. The assessment was conducted in three levels of health care facilities (HCFs), that is, Regional, district hospitals and health centers, existed in 26 regions of Tanzania. Questionnaires, interview and checklists were used as tools for data collection. It was observed that High-Tech incinerators are mainly used in regional hospitals, while district hospital and health center use both High-Tech and De-Montfort incinerators. About 60% of the incinerators have defective doors. More than 55% of incinerators are corroded in regional and district hospitals. The chimney, top plates and grate which are good condition are 55.6% and 60% in regional hospitals and health centers, respectively. The situation is below 50% in district hospitals. The leakage of the roof and loose structures were observed in district hospitals and health center to be more than 50% of the incinerator houses. On other hand, the performance of burners and incinerator housing cleanliness are generally good. It was concluded that the incinerators in the HCFs are in bad conditions, necessitating maintenance.

A new process to improve short-chain fatty acids and bio-methane generation from waste activated sludge

As an important intermediate product, short-chain fatty acids（SCFAs） can be generated after hydrolysis and acidification from waste activated sludge, and then can be transformed to methane during anaerobic digestion process. In order to obtain more SCFA and methane,most studies in literatures were centered on enhancing the hydrolysis of sludge anaerobic digestion which was proved as un-efficient. Though the alkaline pretreatment in our previous study increased both the hydrolysis and acidification processes, it had a vast chemical cost which was considered uneconomical. In this paper, a low energy consumption pretreatment method, i.e. enhanced the whole three stages of the anaerobic fermentation processes at the same time, was reported, by which hydrolysis and acidification were both enhanced, and the SCFA and methane generation can be significantly improved with a small quantity of chemical input. Firstly, the effect of different pretreated temperatures and pretreatment time on sludge hydrolyzation was compared. It was found that sludge pretreated at 100°C for 60 min can achieve the maximal hydrolyzation. Further, effects of different initial p Hs on acidification of the thermal pretreated sludge were investigated and the highest SCFA was observed at initial p H 9.0with fermentation time of 6 d, the production of which was 348.63 mg COD/g VSS（6.8 times higher than the blank test） and the acetic acid was dominant acid. Then, the mechanisms for this new pretreatment significantly improving SCFA production were discussed. Finally,the effect of this low energy consumption pretreatment on methane generation was investigated.