Advanced Organic Waste Management: Sustainable Practices and Approaches

By Chaudhery Mustansar Hussain

Advanced Organic Waste Management: Sustainable Practices and Approaches provides an integrated holistic approach to the challenges associated with organic waste management, particularly related to sustainability, lifecycle assessment, emerging regulations, and novel approaches for resource and energy recovery. In addition to traditional techniques, such as anaerobic digestion, composting, innovative and emerging techniques of waste recycling like hydrothermal carbonization and vermicomposting are included. The book combines the fundamentals and practices of sustainable organic waste management with successful case studies from developed and developing countries, highlighting practical applications and challenges.

Sections cover global organic waste generation, encompassing sources and types, composition and characteristics, focus on technical aspects related to various resource recovery techniques like composting and vermicomposting, cover various waste-to-energy technologies, illustrate various environmental management tools for organic waste, present innovative organic waste management practices and strategies complemented by detailed case studies, introduce the circular bioeconomy approach, and more.

• Presents the fundamentals and practices of sustainable, organic waste management, with emerging regulations and up-to-date analysis on environmental management tools such as lifecycle assessment in a comprehensive manner
• Offers the latest information on novel concepts and strategies for organic waste management, particularly zero waste and the circular bioeconomy
• Includes the latest research findings and future perspectives of innovative and emerging techniques of waste recycling, such as hydrothermal carbonization and vermicomposting

• Language: English
• Publisher: Elsevier Science
• Release date: Jan 6, 2022
• ISBN: 9780323909310

Book preview

Part 1

Organic waste: generation, composition, and health hazards

1 Organic waste: generation, composition and valorisation 3

2 Open dumping of organic waste: Associated fire, environmental pollution and health hazards 15

Chapter 1

Organic waste: generation, composition and valorisation

Dharmendra

Department of Civil and Environmental Engineering, National Institute of Technology, Hamirpur, Himachal Pradesh, India

Abstract

Since human being has come into existence, it has been using the available resources, available to earth for life. Solid waste encompasses the unused or discarded waste obtained from animal and human activities. In ancient times, the disposal of solid waste did not pose a significant problem because population was less compare to availability of per capita land was more. The solid waste comprises organic and inorganic nature, among organic waste due to putrefying nature creates nuisance in nature. In early times, it was general practice to reuse and recycle the organic waste either as fodder or after composting as fertilizer. Because of instance growth of population and urbanization disposal of solid wastes becomes extensive problem for both rural and urban areas in all well settled and developing nations. The main reason for this extensive problem is the rise in organic solid waste, which leads to municipal budget burdens. Problem with disposal of organic waste and due to low municipal budget, valorization of organic solid waste is important to manage this issue. Currently, there is an increase in solid waste management awareness in small and intermediate nations. This results in the enlightening of collection and compact dumpsites and landfills of solid waste management. Therefore, the utilization and valorization of biological solid waste raised more attention all over the globe. Still, carbon-based matters of the municipal biological waste are yet acknowledged less attention than other waste products, like metal, paper, or glass. Frequently, these carbon-based matters are exempted from this value-added sequence. It finishes up on streets or stockpiles on dumpsites, despite its energy content. There, it attracts vector diseases and generates on-site greenhouse gases. Most of the nations in globe are facing difficulties to manage household food waste. For organic waste Solid state fermentation technique is shown an emerging technology. The consumption of domestic food wastes with high dry content to generate high revenues of ethanol by SSF valorization is attained via the bio-conversion of these wastes. Microbes act a vital role in the degradation of carbon-based wastes into their ingredients to transform them into high value-added products.

Keywords

Organic solid waste (OSW); Putrefaction; Greenhouse gas (GHGs); Organic solid-state fermentation (SSF); Microorganisms

1.1 Introduction

Conventional SWM studies have concentrated on thrilling procedures i.e., collection, separation, treatment and disposal because these wastes have thoughtful economic and human impact. Nevertheless, research and practices from the last few decades showed the whole range of solid waste inconsistency in nature and characteristics. The maintenance of these wastes plays an important role in ecosystem of the management authorities due to their environmental impact. There is necessity to understand the problems and significance of variability from the perception of the adaptive reaction of the link of inter-connection of several biotic and abiotic methods and not from the perception of the inconsistency as a levy driver on the system. The MSW covers the domestic, industrial, biomedical and sanitation wastes of any city. This may vary accordingly to socio-economic conditions, population density, culture, industrial uses, urban structures, life styles and waste reduction techniques of the prospective nations. This waste includes carbon based and inorganic wastes because they differ in decomposition problems in nature. In ancient times, organic waste was mainly used either as fertilizer for the agriculture purposes or as fodder. Now rapid increase in population and urbanization created a serious disposal problem of solid wastes in rural and urban areas of most developing and well settled nations. This problem is also due to increasing municipal budget and increment in complex organic waste products.

Problem with disposal of organic waste and due to low municipal budget, valorization of organic solid waste is important to manage this issue. New trend has been observed in developing countries related to management of organic solid waste. This awareness resulted in new trend of collection coverage as well as reduced dumpsite and land fill of waste management practices. In last decade worldwide more attention is given to recycling and valorization of organic solid waste. Albeit food and biodegradable municipal waste are still received less focused compare to other waste products, such as paper, metal, or glass. Despite it has high energy content it ends up on open dump on streets or low lying area. There, it attracts vector diseases and produces on site greenhouse gases.

1.2 Sources, composition and characterization of the solid waste

The issue of the environmentalist is not only the management of certain dumps to clear backyards, roads and other such empty areas where municipal waste accumulates for the visually clean appearance of urban environments or the prevention of repulsive odors or the reduction of visual disruptions to the environment. The main issue is the depletion of forest, ground and surface water supplies where waste is dumped, accumulated or disposed of in a haphazard and non-scientific manner. Such dumping also results in outbreaks of epidemics and generally causes ill-health and diseases affecting local dwellings and tourists. All relevant information relating to origins, quantity and composition is very necessary for the development and operation of the functional elements related to waste management. Functional elements include waste generation, onsite processing and storage, collection, transfer and transport, processing and recovery, recycling and re-use treatment and final disposal. The reliable estimates of MSW generation are vital for effective waste management planning and help taking better financial, regulatory and institutional decisions (Chandrappa and Das, 2012).The composition of MSW varies enormously by one municipality to another and from country to country. Such variance depends primarily on the lifestyle, the economic situation, the legislation on waste management and the industrial structure. The amount and composition of municipal solid waste is important for the proper assessment and disposal of municipal solid waste.

Such knowledge is necessary and beneficial in order to turn solid waste into an energy production system inside the municipality. Depending mostly on calorific value and the elementary structure of the MSW, engineers and scientists will decide on its use as a fuel. In the meantime, this knowledge will help to predict the composition of gaseous pollutants. This MSW is then referred to forms of energy, like gasification, incineration, etc. However, the possible hazardous substances occurring in the ash should be considered carefully (Pfaltzgraff et al., 2013). In this respect, the composition of the waste will provide valuable information on the utility of the material for either composting or for biogas production as fuel via biological conversion. Sources, composition and characterization of the solid waste are classified on the basis of sector and activities (Tchobanoglous et al., 1993).

1.2.1 Source-based classification

Knowledge of the sources and type of solid waste as well as the information on composition and the rate at which waste are generated/ disposal is essential for reduce, reuse, recycle, design and operation of the functional elements associated with the management of solid wastes and these include the following:

(i) Residential: This refers to wastes from dwellings, apartments, etc., and consists of leftover food, vegetable peels, plastic, cloths, ashes, etc.

(ii) Commercial: This refers to wastes consisting of leftover food, glasses, metals, ashes, etc., generated from stores, restaurants, markets, hotels, motels, auto-repair shops, medical facilities.

(iii) Institutional: This mainly consist of paper, plastic, glasses, etc. generated from educational, administrative and public buildings such as schools, colleges, universities, offices, etc.

(iv) Municipal: this includes dust, leafy matter, building debris, treatment plant residual sludge, etc.,

(v) Industrial: This mainly consists of process wastes, ashes, demolition and construction waste, hazardous wastes etc., due to industrial activities.

(vi) Agricultural: This mainly consists of spoiled food grains and vegetables agricultural remains litter, etc., generated from fields, orchards, vineyard, farms, etc.

1.2.2 Type-based classification

The functional elements include waste generation, on-site handling and storage, collection, transfer and transport, processing and recovery, recycling and reuse, treatment and final disposal. Classification of wastes based on types, i.e., physical, chemical and biological characteristics of waste, is as follows (Phelps et al., 1995):

(i) Garbage: this refers to animal and vegetable wastes resulting from the handling, sale, storage, preparation, cooking and service of food. Garbage comprising these wastes contains putrescible organic matter, which produces an obnoxious odor and attracts rats and other vermin. It, therefore, requires special attention in storage, handling and disposal.

(ii) Combustible and non-combustible wastes: Combustible waste means the organic content of solid waste, including paper, cardboard, cartons; wood, boxes, excelsior, plastic, textiles, bedding, leather, rubber, paints, yard trimmings, leaves, and household waste all of which will burn. Non-combustible Material. A material that, in the form in which it is used and under the conditions anticipated will not ignite, burn, support combustion, or release flammable vapors, when subjected to fire or heat.

(iii) Ashes and residues: Ash is the solid, somewhat powdery substance that is left over after any fuel such as wood, coal, charcoal and other combustible materials used for cooking and heating in houses, institutions and small industrial establishments. Incomplete combustion means that there is not enough oxygen present when the material is burned to completely consume the fuel and leftover residues.

(iv) Bulky wastes: Bulky waste or bulky refuse is a technical term taken from waste management to describe waste types that are too large to be accepted by the regular waste collection. It is usually picked up regularly in many countries from the streets or pavements of the area. These includes large household appliance such as refrigerators, washing machines, furniture, vehicles parts, tyres wood and tree branches. They require a special collection mechanism.

(v) Biodegradable and Non-biodegradable wastes: A biodegradable substance can be defined as a material which can be decomposed by microorganisms or decomposers and not be adding to any type of pollution. Waste that cannot be decomposed by the biological ways is called the Non-biodegradable wastes. Because of the action of microorganisms, these wastes are degraded from complex to simpler compounds depends upon their degeneration time. Table 1.1 below shows a comparison of biodegradable and non-biodegradable waste with their degeneration time.

(vi) Farm Wastes: These types of wastes constitute from various agricultural activities e.g., planting, slaughter, rearing of animals, harvesting and the operation of feedlots. In various areas, the disposal of animal waste from feedlots, dairies and poultry farms has become a serious issue. In initial times, to recycle the organic waste either as fertilizer or fodder it was general custom. In many developed and developing countries, because of population rupturing and urbanization situation removal of farm wastes is a stinging and extensive problem in both types of areas i.e., rural and urban areas.

(vii) Sewage wastes: the solid products which are mostly organic in nature are considered as sewage waste. This type of organic waste comes from the treatment of organic sludge which is isolated from two types of sewages i.e., one is raw sewage and other one is treated sewage. At the initial state of treatment, the process of isolation of grit and eggshells is done which contains mainly the inorganic fraction of raw sewage and it should be immerse without any delay because it may entrain putrescible organic matter with pathogens. The majority of processed, dewatered sludge is helpful as a soil conditioner but there will be economical constrained on this. If this type of waste is quite well mixed with some type of biodegradable solid waste, it can be helpful to achieve good quality manure.

(viii) Dead animals: The animals which are died either accidentally or naturally are burdens to municipal wastes. This type of waste will not be considered as industrial waste because it does not contain animal parts from slaughter-houses and carcasses. These animals are categorized into two classes i.e., large and small. The animals which come under the large category are pigs, goats, horses, buffalo, cow etc., and the small ones are cats, rats, dogs etc. This categorization is required because of requirement of special equipment for the management of dead animals when they need to be removed. If not removed properly, this will be a big threat to public health safety since they attract flies as they exposed openly.

(ix) Construction and demolition wastes: This type of wastes comes from manufacturing, repairing, refurbishment and demolition of houses, private enterprise buildings and other structures. This waste contains mainly stones, concrete, bricks, lumber, roofing and plumbing materials, heating systems and electric wires.

(x) Hazardous wastes: Hazardous wastes can be of any type in nature i.e., liquid, solid, gas or sludge, having properties which makes them harmful threat for human health and the environment. They can be discarded commercial products, like cleaning fluids or by-products of industrial plants. Among these four properties i.e., ignitability, corrosively, reactivity, or toxicity, it must contain at least one. Some examples of this type of wastes are vacant vessels of solvents, paints and pesticides, which are usually combined with municipal wastes and become part of the urban waste. Proper management is required for waste from hospitals pathology labs.

Table 1.1

1.2.3 Generation, composition and characterization of the solid waste

To assess substitutes in terms of appliances, plans, structure and management programme, the knowledge of generation, composition and characterization of the solid waste is required. Solid waste management still has diverse gaps in the management sequence which are required to be fulfilled, because of divergent imperfections such as the absence of waste collection, inadequate processing, isolation already at the origin, sparse reuse, missing recycling systems, and often unsuitable removal. Physical and chemical properties of the organic waste parts are changed during its processing for energy and resource recovery. In this context, the most important processing techniques encompass composting (aerobic treatment) or bio-methanogens (anaerobic treatment in biogas reactors). A stable product called compost is produced during the composting through aerobic processing, which is worldwide used as soil fertilizer, manure and soil conditioner (Saleh and Koller, 2019). Some of the general examinations related with the composition of wastes include the following:

(i) The utmost ingredients are paper and decomposable organic materials.

(ii) More often than not, the part of the composition is formed from metal, glass, ceramics, textile, dirt and wood and their relative quantity depends on local factors.

Within a certain community the waste composition deviates globally with the socio-economic status, for example, life style determined by income, composition pattern as shown in Fig. 1.1 and cultural conduct demonstrate this fact globally as well as in India. This figure shows the share of most of developed countries for population is less in comparison to global MSW generation, while India and China show reverse order.

Figure 1.1 Share of global population and municipal solid waste (MSW) (Data sourced from Linnenkoper, 2019).

The countries of world are categorized into regions, e.g., the Middle East and North Africa (MENA), East Asia and Pacific (EAP), South Asia (SA), Europe and Central Asia (ECA), North Asia (NA), Sub-Saharan Africa (SSA) and Latin America and Caribbean (LAC). The rate of MSW generation is developing even faster than the rate of urbanization as the universe moving toward its urban future. In 2016, the biggest amount of MSW (23 percent) is generated by EAP worldwide, followed by ECA 20 percent, SA 17 percent, NA 14 percent, LAC 11 percent, SSA 9 percent and MENA 6 percent (World Bank Group, 2018). However, by 2050, the predicted progress rate of MSW production is 197 percent for SSA, 98 percent for SA, 75 percent for MENA, 60 percent for LAC, 53 percent for EAP, 37 percent for NA and 25 percent for ECA, as shown in Table 1.2. In case of per capita waste production, the aggregate waste production rate in the NA was much higher (2.21 kg/capita/day) in comparison to ECA (1.18 kg), LAC (0.99 kg), MENA (0.81 kg), EAP (0.56 kg), SA (0.52 kg) and SSA (0.46 kg) World Energy Council (WEC), 2016 (Sharma and Jain, 2020). Because of high economic growth and urbanization rate MSW can be produced triple, double and double by SSA, SA and MENA regions respectively in the coming three decades, Except for NA, the maximum part of the waste in all remaining province was an organic waste (around 40 percent). Less than 30 percent of organic waste was found in the NA region and more than 55 percent of total waste was dry recyclables which was above the one-third in all EAP, ECA, LAC and MENA regions. A large quantity of wastes (about 30 percent) which is not categorized into SSA can be considered as inert waste. Therefore, it clarifies the fact that the waste compositions are certainly effected by urbanization and income levels of the country.

Table 1.2

Source: Data from World Energy Council (WEC), 2016; and the World Bank Group (2018).

The characteristics of new MSW like designing, planning, upgrading or operating SWM systems are very critical. The processes i.e. analysis and characterization of waste generates from different sources in MSW gathers information on the composition and quantity of solid wastes.

1.2.3.1 Physical features

The most important features of the MSW i.e., permeability, bulk density, moisture content and physical composition etc., are crucial for planning of the system. These are as follows:

(i) Bulk Density: This is important factor for the design of SWM system and its unit is kg/m³. The bulk density is measured through the following steps:

1. Record the weight of W1.

2. Overfull the specimen into the vessel.

3. Drop the sample from 10 m height for 3 times for settlement of the contents.

4. Fill the vessel volume with remaining sample and measure volume (V2).

5. Record the weight (W2). And calculate bulk density = W2-W1/V1

(ii) Moisture Content calculation: It is the proportion of water to whole weight of the damp waste. Increase in moisture content increase the weight of solid wastes and overall cost of the transportation and collection. There are following steps for the measurement:

1. Record the weight W1.

2. Spread the specimen over the several trays.

3. Place the sample in oven for 24 h

4. Cool the samples at room temperature and record the weight W2.

5. Measure the moisture content = (W2-W1/W2)*100

(iii) Size: The distribution of the particles in waste stream is most crucial parameter due to its consequence in the design of shredders and mechanical separators.

1.2.3.2 Chemical characteristics

Understanding of chemicals and characteristics is very necessary for the behavior of waste for examples degradation of waste and heating values. The chemical features are very important for reuse of waste for better utilization and these are as follows:

(a) Chemical: Chemical characteristics include pH, Nitrogen, Phosphorus and Potassium (N-P-K), total Carbon, C/N ratio, and calorific value.

(b) Bio-Chemical: Bio-Chemical characteristics include carbohydrates, proteins, natural fiber, and biodegradable factor.

(c) Toxic: Toxicity characteristics include heavy metals, pesticides, insecticides, Toxicity test for Leachates (TCLP), etc.

(i) Lipids: Oil, fat and grease are included in the class of chemicals. These have about 38 thousand kcal/kg of calorific values which leads suitability of waste for energy recovery processes. Due to its low solubility in water it have lower rate of degradation of waste.

(ii) Carbohydrates: It is mainly found in food and yard waste. This contains sugars and its polymers. It is also rapidly decomposed into by-products i.e., water, carbon dioxide and methane. Flies and rats are attracted by the degrading of carbohydrates therefore it should not be left open for long period.

(iii) Proteins: Proteins are those compounds which encompass Hydrogen, carbon, nitrogen and oxygen and organic acid with amine group. These cover about 5–10 percent of dry solids in waste and primarily found in garden waste and food. It degrades into amino acid and also leads in extremely unkind odors.

(iv) Natural Fibers: This class comprises the natural compounds, cellulose and lignin, both of which are resilient to biodegradation. They are found in paper and paper products and in food and yard waste. Cellulose is a larger polymer of glucose while lignin is composed of a assembly of monomers of which benzene is the prime member. Paper, cotton and wood products are 100, 95 and 40 percent cellulose correspondingly. Since they are extremely flammable, solid waste having a high ratio of paper and wood products, are appropriate for burning. The calorific values of oven dried paper products are in the range 12,000 – 18,000 kcal/kg and of wood about 20,000 kcal/kg, which compare with 44,200 kcal/kg for fuel oil.

(v) Synthetic organic material (Plastics): They are highly resistant to biodegradation and, therefore, are offensive and of special fear in solid waste management. Hence the increasing consideration being paid to the recovering of plastics to reduce the ratio of this waste component at disposal sites. Plastics have a high heating value, about 32,000 kJ/kg, which make them very appropriate for burning. But, one should note that polyvinyl chloride (PVC), when burnt, produces dioxin and acid gas. The latter increases corrosion in the combustion system and is liable for acid rain.

(vi) Non-combustibles: This group comprises glass, ceramics, metals, dust and ashes, and accounts for 12 – 25 percent of dry solids.

(vii) Heating value: An assessment of the potential of waste material for use as fuel for incineration requires a purpose of its heating value, expressed as kJ/kg. The heating value is determined experimentally using the Bomb calorimeter test, in which the heat produced; at an unceasing temperature of 25 °C from the combustion of a dry sample is restrained. Since the test temperature is below the boiling point of water (100 °C), the combustion water remains in the liquid state. However, during combustion, the temperature of the combustion gases extents above 100 °C, and the ensuing water is in the vapor form. While evaluating burning as a means of disposal or energy recovery, one has to consider the heating values of particular ingredients. Table 1.3 shows the typical inert residue and heating values for the constituents of municipal solid waste.

(viii) Definitive investigation: This states to an analysis of waste to determine the ratio of carbon, hydrogen, oxygen, nitrogen and sulphur, and it is done to achieve mass balance calculation for a chemical or thermal process. Besides, it is essential to determine ash fraction because of its possibly destructive environmental effects, carried about by the incidence of toxic metals such as cadmium, chromium, mercury, nickel, lead, tin and zinc. One should note that other metals (e.g., iron, magnesium, etc.) may also be present but they are non-toxic. The following Table 1.4 shows an ultimate analysis of a typical municipal solid waste.

(ix) Proximate analysis: This is significant in assessing the combustion assets of wastes or a waste or refuse derived fuel as presented in Table 1.5. The portions of attention are:-

• Moisture content, which adds weight to the waste without growing its heating value, and the evaporation of water reduces the heat released from the fuel;

• Ash, which adds weight without producing any heat during ignition;

• Volatile matter, i.e., that percentage of the waste that is improved to gases before and during incineration;

• Fixed carbon, which signifies the carbon residual on the surface grates as charcoal. A waste or fuel with a high quantity of fixed carbon necessitates a longer retaining time on the incinerator grates to attain whole incineration than a waste or fuel with a low amount of fixed carbon.

Table 1.3

Table 1.4

Table 1.5

1.3 Wastes as a wealth and source of income

People were generating millions of tons of waste per day, and due to rapid industrialization and population growth, this will only increase. There are several of sources where from wastes can be generated. This includes rubbish or garbage from households, schools, offices, marketplaces, restaurants and other public places. These are the following items like food debris used plastic bags, soda cans and plastic water bottles, broken furniture, broken home appliances, clothing, etc. produced every day. Fifty percent of global waste is produced by urban areas due to consumption of seventy-five percent of the world's natural resource consumption. The waste management systems currently used in most of the developing countries, especially low- and middle-income nations, were practicing to collect, segregate, process and recycle this waste are insufficient and cannot meet demand (Harbord, 2017). Making Money from Waste could be better option to resolve solid waste management issues as well as this practice help to boost up the economy of all country worldwide.

Dumping of untreated organic garbage are awful effects on the surrounding environment as well as human health. Such acts could lead to a global disaster with people literally drowning in their own garbage. In fact, there are many practical waste reuse projects already being implemented all around the world. There is some example, where biogas is produced by using poo in Nairobi, Kenya a community-based organization in the city's biggest slum, Kibera. Another example, in Bangalore, India, the company Terra Firma uses a variety of approaches to produce compost from municipal solid waste, including windrow composting, where waste is kept in piles to decompose and then sieved to produce manure. The company commercially supply this compost to farmers who use it as organic fertilizer in their agriculture lands. This shows the potential for this new market is very high from waste to wealth. The World Economic Forum has also estimated the potential global revenue from the biomass value chain (i.e. the process of converting organic material to energy) to reach up to USD 295 billion by 2020 (Harbord, 2017). German equipment manufacturer, BHS-Sonthofen has explained an efficient biogas production process from the bio grinder works for multiple feed materials. A biogas plant near Chandigarh in the state of Punjab, the Indian company source facility has installed a BHS Bio grinder to process paddy straw, coconut shells and other organic waste materials for the production of biogas.

1.4 Valorization of organic solid waste

Worldwide per year around 1.3 billion tons of food are wasted. It is originally produced under extensive use of energy and nutrients. A biotechnological process provides an innovative way to recover parts of the energy and nutrients initially spent on food production as feedstock. There are chemical and biological process is enables the production of a wide range of nutrients products by using microbial metabolism as well as food waste is hydrolyzed to glucose, free amino nitrogen and phosphate. Waste valorisation concerns with the process of converting waste materials into more useful products including fuels, materials, and chemicals (Abdel-Shafy, 1996). The food waste 357 million tonnes produced annually by industrialized Asian countries as Japan, China and Republic of Korea. It is followed by South & Southeast Asia (275 million tonnes) and Europe (205 million tonnes). Also 100 to 130 million tonnes of food are wasted per year in Sub-Saharan Africa, Latin America, North America and Oceania, North Africa and Western & Central Asia, respectively. This amount includes all kinds of food, such as cereals, roots and tubers, oil seed and pulses, fruits and vegetables, meat, seafood, milk and eggs (Gustavsson et al., 2011, 2013). The production of food to full fill the demand of energy and nutrients as well as elimination of food waste by dumping into landfill site is in appropriate way may leads environmental consequences (Cuéllar and Webber, 2013; Zilbermann et al., 2013). There are several research studies have been carried out to resolve the problem by incineration and anaerobic digestion, or to use food waste as feed for pigs and cattle in order to close the nutrient loop (Sayeki et al., 2001). Further, organic waste including food waste and sewage sludge can be composted and vermicomposted employing earthworms to produce nutrient-rich, properly sanitized organic manure for agronomic applications (Hait and Tare, 2011a; Hait and Tare, 2011b; 2012; Swati and Hait, 2017; 2018). There are also possibilities to produce energy from food waste.

1.5 Conclusions

Most of the nations in globe are facing difficulties to manage household food waste. Due to inadequate practice of collection and characterization of organic waste may lead vulnerable condition to environment and ecosystem, thus it represents a real threat to human health. The amount and composition of municipal solid waste is important for the proper assessment and disposal of municipal solid waste. Such knowledge is necessary and beneficial in order to turn solid waste into an energy production system inside the municipality. However, the possible hazardous substances occurring in the ash should be considered carefully. This review reported approaches for the valorisation of food waste in biotechnological processes which was developed in recent years. The recovery of carbon, nitrogen and phosphorous from food waste by chemical and biological methods enables the recycling of valuable nutrients for the production of chemicals, materials and energy. Valorisation of food waste is not only an environmentally benign waste treatment, but it also benefits to the bio-based economy, as pure and expensive nutrient sources can be substituted. The integration of food waste treatment in existing biotechnological processes can shorten the pathway from no value waste to value-added products. Together with green chemical technologies, it contributes to a sustainable society.

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Chapter 2

Open dumping of organic waste: Associated fire, environmental pollution and health hazards

Digambar Chavana,b, Shashi Aryaa,b and Sunil Kumara,b

aCSIR-National Environmental Engineering Research Institute (CSIR-NEERI), Nagpur, Maharashtra, India bAcademy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, India

Abstract

Municipal solid waste (MSW) in the majority of the developing countries is being dumped at open dumpsites. Fifty percent of the MSW disposed of at open dumpsites is organic in nature. Openly dumped organic waste gets degraded due to biological and chemical processes which may result in the generation of heat inside the dumpsite. The heat generated inside the dumpsite may cause initiation of spontaneous fires which are considered as one of the most intense causing environmental pollution and threat to human health. The occurrence of spontaneous fires due to heat generation from the biological and chemical degradation of organic waste at open dumpsite can cause a threat of air pollution, loss of lives of specially dumpsite workers, deterioration of leachate quality and may have long-term health impacts on the people living nearby the dumpsite. Organic waste dumped at the dumpsite may smolder for the weeks during elevated temperature level (i.e. during the summer season) which is complex in nature and very difficult to detect. The horizontal or vertical propagation of the waste smoldering at open dumpsites may emit toxic pollutants, such as dioxins and furans due to ignition of other non-biodegradable waste components. Fire at MSW dumpsite is a growing concern for decades especially in the developing countries and hence special attention is required to be given for its prevention. The issues and challenges associated with the open waste burning need to be addressed properly for its effective control and mitigation.

Keywords

Organic waste; Landfill fire; Health hazards; Environmental impacts; GHG emission

2.1 Introduction

Management of huge quantum of Municipal Solid Waste (MSW) is a challenging issue all over the world in terms of its environmental pollution, sustainability and social inclusion (Gupta et al., 2015a, 2015b; Vitorino de Souza Melare et al., 2017a, 2017b; Ferronato and Torretta, 2019). MSW treatment requires an integration of various waste treatment processes such as biomethantion, composting, incineration, pyrolysis and engineered landfilling followed by 4R principle i.e. reduce, reuse, recycle and recover (Vincenzo Torretta, 2016). Special attention shall be given in developing countries where the quantum of everyday MSW is high requires a decentralized approach to minimize the burden on the existing unstable MSW management system (Vitorino de Souza Melare A et al., 2017). In-country like India, per capita MSW generation varies between 0.2 kg/day to 0.8 kg/day and the rate on annual waste generation is around 42 million tons (Sharloy M. et al., 2008; Ogwueleka T., 2009; Rana R. 2015; Sharma et al., 2018). In India, an expected increase in MSW generation per year is around 5 percent which creates an additional burden on the existing MSWM system. Around 90 percent of the waste collected in Indian Urban local bodies (ULBs) is disposed of at open dumpsites (Kumar et al., 2009).

The practice of waste dumping on open land without adopting engineered landfilling measures creates serious threats to the surrounding air, water and soil environment as well as on human health. Metal compounds present in MSW gets mixed on land and leachate formation due to the precipitation and infiltration contains elements like Cr, Ni, Fe, Cu, Mg, Pb and organic compounds such as benzene, phenols, toluene, acetone, polyaromatic hydrocarbons, and chloroform etc. The degree concentration of these elements depends majorly on the physico-chemical composition of MSW. Some of these potential pollutants are dominantly present in leachate which gets adsorbed into the landfill soil and may poses threat of groundwater contamination in surrounding areas of the MSW dumpsite.

2.1.1 Problems associated with the organic waste

MSW dumped at open dumpsite is comprised of more than 50 percent of organic content which generates an enormous amount of heat in dumpsite sub-surface due to the long-term exothermic organic waste degradation. Heat generation due to the chemical and biological waste degradation led to the initiation of the spontaneous waste fires which has severe environmental impacts (Chavan et al., 2019). Open burning of MSW causes emissions of CO2, CO, CO, SOx, NOx, SPM and toxic gas emissions due to interactions with other inorganics dumped at landfills (Rana R., 2015). Organic waste going to landfills can be diverted to decentralized waste treatment processes to minimize the risk associated with its management (Sharma et al., 2018). The release of organic litter sea or any of the river water body may strongly affect the marine environment and it poses a serious long-term hazard to marine eco-system (Das et al., 2016). Open dumping of organic waste in developing countries has severe environmental as well as social impacts, which restricts the efforts of the countries trying to achieve sustainable development goals (SDGs).

2.1.2 Existing status of organic waste management

For the economic boost in developed and developing countries along with sustainable development, the principle of changing the existing pattern of gods and resources were introduced in SDGs. These will reduce environmental pollution and may improve environmental sustainability in the waste sector. The goal of the global waste management program was to ensure the access of safe and affordable solid waste collection services in all parts of the world by 2020 and to improve the waste sustainability by controlling open dumping and burning by 2030. Cost-effective treatment options such as biomethnation and composting are very significant for the treatment of organic waste and the overall improvement of the existing SWM system especially from the developing countries like China and India. Waste-to-energy plants for the energy generation and treatment of inorganic waste along with recycling programs are very crucial for the treatment of existing waste. Soil, air and groundwater contamination in the waste management sector is a significant issue especially for developing countries like India and China. And it has been recognized as a growing concern for decades due to the increased population and rate of the waste generation. Considering the existing pattern of SW generation in developing countries region-specific strategies shall be implemented to reduce the associated environmental pollution from the waste sector.

Open dumping of organic waste creates at MSW dumpsite creates problems, such as soil pollution, slope failure, abrupt leachate generation, groundwater pollution and GHGs emission in the atmosphere. In India and other developing countries waste receiving capacity of the most open MSW dumpsite located in metropolitan cities is already exhausted. Frequent fires, leachate percolation and SPM emissions at MSW landfills are making them as a potential point source of the environmental pollution. Leaching of a foul dark liquid (leachate) from the older waste heaps at MSW dumpsite is comprised of the higher degree of the heavy metal contamination. Leachate produced can pollute the soil environment around the MSW dumpsite which is irreversible. Poor waste management and disposal practices have been leading to the creation of legacy waste (huge waste dumps) in cities which are affecting the surrounding environment and health of the people living near to these open dumpsites. Existing challenges for the management of MSW are shown in Fig. 2.1.

Figure 2.1 Existing challenges for management of MSW.

2.2 Fires at MSW landfills

Open dumping of the waste at MSW dumpsites mostly lead to heat generation and spontaneous waste fires due to the long-term exothermic degradation of organic waste. The effect of the diurnal or intrapersonal ambient temperature cycle in a dry tropical climate has an impact on the waste temperature present in dumpsite sub-surface which ignites during the elevated temperature level and resulting in huge intense landfill fires. The risk of these waste fires is very high in India and other developing countries where the major portion of the everyday waste is directly dumped at open dumpsites. Open MSW dumpsites are non-engineered and do not have adequate LFG extraction and fire management system due to which occurrence of fire may cause potential environmental impacts. Frequent waste fires at MSW dumpsite poses life threat to the dumpsite workers and rag pickers due to the toxic gas emissions. Waste burning creates voids in the dumpsite sub-surface which poses a threat of falling mostly for dumpsite workers and rag pickers. Spontaneous waste fires are very complex due to the involvement of aged organic refuse which contains polythene and other inorganics. Unscientific and non-engineered landfills do not have any leachate collection system due to which leachate percolates in the soil environment and pollutes groundwater.

The impact of spontaneous waste fires is very high in developing countries due to various reasons such as lack of waste segregation mechanism, biochemical waste degradation and heat generation, poor operation and maintenance facilities and intentional waste burning at MSW dumpsite. Disposal of the uncompact buried waste refuse at MSW dumpsite is also a major cause for the occurrence of fire. Studies are required to explore the intensity of the heat accumulation in MSW landfills and the sensitivity of the organic waste diversion program on the frequency of the occurrences of waste fires. Various aerobic and anaerobic and chemical oxidation processes that occur simultaneously in the landfill generate an enormous amount of heat which is not dissipated at the rate at which it is produced. This sometimes leads to smoldering and sustained smoldering under congenial conditions leads to the fires.

Heat loss from the landfill sub-surface is minimal due to which it affects the waste temperature. Availability of the fuel (CH4 and solid waste), heat and intrusion of oxygen from the atmosphere forms fire triangle inside the landfill sub-surface which results in spontaneous waste fires. Formation of the fire triangle and types of spontaneous waste fires is shown in Fig. 2.2.

Figure 2.2 Formation of the fire triangle at MSW landfill.

Waste fires at MSW dumpsite may occur at surface and in sub-surface. Surface fires at MSW landfill occur due to the accidental sparks or intentional waste burning and also because of the rekindling of the buried refuse. Surface fires at MSW landfill are easy to detect and control. Waste fires inside the landfill surface are very complex and difficult to detect and mitigate. Surface fire can easily be detected and monitored. It has been reported that if the fires at MSW landfill surface are not controlled they may propagate across all the direction and become more severe and harmful (FEMA, 2002). The sub-surface fire inside the landfill structure is governed by the organic waste degradation process and chemical oxidation process. Types and functions of spontaneous waste fires are shown in Fig. 2.3.

Figure 2.3 Types of waste fires at MSW landfill.

If a sub-surface fire occurred at MSW landfill it may smolder for the months and emit toxic gases produced from the incomplete combustions of the waste in sub-surface (Weichenthal et al., 2015). Waste dumped at MSW dumpsite is heterogeneous and contains different waste components like paper, cardboard, newspaper, polythene, rubber, wood, textile and inert etc. Each of the waste components has different thermal properties and behavior in the process of spontaneous waste ignition. Causes of spontaneous waste fires at MSW landfill are shown in Fig. 2.4.

Figure 2.4 Causes of spontaneous waste fires at MSW landfill.

Identification of the most susceptible waste component responsible for the spontaneous waste ignition may play an important role in the effective prevention, control and mitigation of spontaneous fires. Several studies reported that the spontaneous waste ignition at MSW landfill is governed by the various factors like moisture content, temperature, oxygen concentration and presence of catalysts etc. (Kawatra and Hess, 1999; Buggeln and Rynk, 2013). Factors which are required for the initiation of the spontaneous waste ignition in landfill sub-surface may change according to the site-specific conditions and seasonal temporal variations. Organic waste degradation at MSW dumpsite causes CH4 generation in sub-surface and it might continue even after the closure the MSW dumpsite (Chavan and Kumar, 2018). Prevention measures required for the control of landfill fire are shown in