Solid Waste Engineering and Management

Solid waste management (SWM) has always been an integral feature of every human society and has become a growing global concern as urban populations continue to grow as well as consumption patterns change. The health and environmental consequences of SWM are becoming increasingly urgent, particularly in developing countries. In this sense, sustainable and integrated solid waste management emerges as a solution to the growing global challenges of disposing of municipal solid waste (MSW). SWM is a cross-cutting issue that can be directly or indirectly linked to the 17 UN Sustainable Development Goals (SDGs) because it is an essential utility service. The three dimensions (or pillars) of sustainability are the environment, the economy, and society. Sustainable solid waste management (SWM) is a multifaceted issue with political, socioeconomic, institutional, and environmental components. It has become one of the most significant issues confronting urban spaces in developing countries as a result of exponential urban growth. Integrated solid waste management (ISWM) aims to optimize the management of solid waste from all waste-generating sectors, collection, transportation, and disposal while involving all stakeholders (waste generators, service providers, regulators, government, and community/neighborhoods).

Shifting toward a circular economy has obtained huge attention from countries all over the world as a sustainable route to reduce the mounting volumes of solid waste, which has a direct link with today’s economy. Recently, the single-stream recycling technique has obtained sufficient interest. In this recycling technique, all the recyclable materials are collected in a single container. Accordingly, this chapter introduces the process of single-stream recycling with the help of a detailed case study. It also illustrates numerous requirements for MRFs such as site selection, amount and quality of household waste generation, moisture contents, and their environmental impacts. A special focus on the economic and life cycle aspects of MRFs has been taken into consideration. Various recommendations for future research and direction are proposed.

Over the years, construction waste has risen, causing environmental concerns as well as a loss of profit for contractors. This chapter covers the concepts, causes of waste generation, characteristics, waste management methods, waste minimization, disposal, rules, and worker’s efficiency in relation to construction and demolition waste. The waste management hierarchy is also explained in the chapter. The authors looked at the causes of waste generation and disposal, as well as the characteristics and methods of waste management, along with the regulations that apply. This chapter discusses some of the data and applications of Construction and Demolition (C&D) waste management and its disposal in Malaysia, which are also commonly being practiced in other countries.

Global plastic waste production had increased from 245 million metric tons in 2008 to 359 million metric tons in 2018, and this value is expected to be boosted by three times in the year 2050. The sudden change of human lifestyle during the pandemic of Covid-19 toward online shopping and panic buying to restock kitchen shelves has resulted in a high impact on the plastic industry and plastic waste management. The pandemic requires significant plastic waste management changes and severely affected plastic waste reduction’s current policies and strategies. Valorization of plastic is a desirable approach in managing a sudden surge of plastic waste during the outbreak of the covid-19 pandemic as this recovery approach will change the plastic waste into valuable products. The present study reviews the current technologies on the recovery approaches of plastic into valuable products. The recovery approaches that cover mechanical recycling, energy recovery, and chemical recovery are discussed. The concept, mechanism, and performance of each approach are reviewed. The use of plastic in concrete, road construction, and soil treatment is highlighted under mechanical recovery. The heating value of plastic waste is used to discuss plastic waste combustion through the incineration process for energy recovery. The chemical recovery involves depolymerizing plastic waste through chemolysis, and thermolysis is discussed and compared. The review can conclude that the current technologies in the recovery of plastic waste will improve waste management, sustainability of resources, and shift toward the circular economy.

Most of the marine waste and litter found in the oceans originated from lands due to human activities. These wastes are either transported from the land directly into the sea by rivers, stormwater run-offs, beach activities, and winds or occur due to the legalized disposal of wastes at certain designated areas in the oceans. The increasing volume of waste in the oceans, where most of it is plastic waste, is endangering the sea creatures. As these wastes reach the ocean, they may stay afloat or sink to the seabed, depending on their size and density. Plastics in the aquatic environment will degrade over time into small pieces that are called microplastics. These microplastics can move up through the food chain as humans consume sea life that have been eating these microplastics in the aquatic environment. This issue has been aggravated since the COVID-19 outbreak in the late 2019, which led to tonnes of discarded face masks and rubber gloves ending up in the oceans. UNEP and IOC established guidelines for beach litter and benthic sampling method to quantify the amount and sources of these litters. In addition to these, under the London Convention 1972 several regulations and policies were established around the world to regulate ocean dumping.

This chapter introduces the potential recycling of sewage sludge in landfill cover application. The subtopic includes the generation and properties of sewage sludge as well as the current practices on sludge handling, treatment, and management. Since 2000, the recycling of sewage sludge has gained interest around the world in order to manage the sludge sustainably and economically. Nevertheless, sludge modification is required to stabilize and enhance the mechanical and geotechnical performance of the sludge. The leaching behavior was also studied in order to address the short- and long-term environmental effects of using the modified sludge for various applications.

Food waste, particularly originated from restaurants, has become an appearing issue as a point source pollutants to land, water, and air (i.e., greenhouse gas (GHG) emissions). The management and recycling of restaurant food waste have thus become a key priority for restaurant owners to mitigate the food waste amount that they generated. This chapter reviews information on the sources, composition, and characteristics of restaurant waste. The environmental policy and regulation of food waste worldwide, as well as in selected Asian countries, were also briefly presented, followed by the main discussion of this chapter related to management, recycling, and disposal of restaurant food waste. Various options/methods to handle or convert food waste to the valuable product were reviewed, which includes feeding livestock, composts/fertilizers, biogas from anaerobic digestion, and various biobased chemical building block. This chapter ends with the case study, where two case studies were discussed related to lactic acid production from the food waste collected from the restaurant located at the ATB Potsdam, Germany, and the potential biorefinery products from the conversion of food waste obtained at the restaurant in Monastiraki Square and Plaka, Athens, Greece.

In terms of solid waste management, landfills are the favored disposal strategy. Before an area is established as a landfill, certain crucial things must be focused on and acted upon. In its most basic form, a landfill is a location where trash is “thrown” or “dumped.” However, developing a landfill necessitates a great deal of engineering expertise. A sanitary landfill is an engineered technique for disposing of solid waste on land that is designed to cause the least amount of environmental harm and inconvenience. As a result, the sanitary landfill design includes a detailed description and plan that ensures the safe and effective disposal of solid waste. This chapter goes through the types of sanitary landfills and the critical design requirements. Site selection, landfill liners, landfilling technology, and landfill cover system up to closure stage are all part of the sanitary landfill design. Every part must be properly designed; otherwise, the ecosystem will suffer. Because a sanitary landfill is a site where solid waste is disposed of in an engineered manner, the environmental effect is reduced or eliminated.

Landfilling is considered the most common method for solid waste disposal and treatment. Landfilling method has the advantages of low cost and effectiveness, as well as simplicity; however, this disposal method needs to be managed properly in order to prevent and mitigate environmental contamination. Landfilling causes the generation of leachate which is a regularly expected phenomenon in all landfills. Leachate is considered very contaminated wastewater that consists of mixtures of toxic inorganic and organic pollutants and high concentrations of natural organic matter. Hence, the characterization of leachate is an important step toward preventing environmental pollution and assessing the efficiency of leachate treatment facilities. Moreover, it is of significant importance to discuss and understand the collection and recirculation systems used to manage the generated leachate from different landfills. Therefore, this chapter will introduce and summarize different topics related to landfill leachate generation, including leachate generation modeling, leachate collection systems, leachate characterization and quality, and leachate recirculation systems. Finally, the operational issues that could face leachate collection systems and their management strategies are further discussed.

Management of a landfill is a continuous process that proceeds long after the active landfill period, which is called landfill post-closure/after-care management. In most developed and developing countries, this after-care period is regulated for a minimum of 30 years after landfill closure. This ensures waste stabilization within the landfill layers, and there are minimal environmental threats to the surrounding area, especially from the leachate and landfill gas emissions. This chapter covers the legislation and requirements imposed by most countries related to the proper management of landfills during this passive phase, which involves the monitoring requirement and emission evaluation. The basic principles of landfill technology, its types, and operation will first be discussed as it influences after-care management. Emphasis will be made toward three methods/approaches (evaluation through target value, evaluation using impact/risk assessment, and evaluation through a performance-based system) in determining the completion or endpoint for the post-closure period. Both the advantages and disadvantages of each method will be further discussed and summarized.