Environment BCA

• Construction of drones and helicopters for easy transportation of food packets for all the victims who are in need is handled by the electrical technicians. • Power control during heavy rainfall resulting floods and prevention of shocks with water being a good conductor of electricity is ensured by the electricians by timely cutting off the electricity supply. • They also make sure secure earthing pits during the electrical installation which could be a major problem at the time of earthquake if not done right. • Electrical motors and generator installation in drought-prone areas are done by electrical engineers which eradicate the further drying up of the region and provides the water supply for the victims. • They have an important role in providing electricity to all kinds of disaster hit zones and giving them the luxury of power at the time of crisis. Role of Civil Engineers: - • With strong building foundation, the risk of collapsing of any building can be easily prevented. A geotechnical engineer is responsible for the construction of such high earthquake resistant buildings enhancing the infrastructure. • For the flood control and destruction of dams, the hydraulic engineer provides all the required information about the various bridges and dams and advanced designs for prevention. • City planners and project managers study the vulnerabilities providing proper guidelines required for provides rough and tough infrastructure withstanding any outer force. • Rescue operations and safety escape routes must be established in every building along with possible reconstruction of the entire building is controlled by a structural engineer. • Hazardous and toxic wastes, air pollution control, drainage development and radiation protection are handled by the environmental engineer which is essential once the disaster has struck in order to control the after effects. Role of Mechanical Engineers: - • Contractors work along with the structural engineers to come up with shockproof infrastructure right before the construction of the building. • The planning of raw steel used in bridges, tracks, buildings, which kind of cement to be used is done by the mechanical engineers. • Mechanical Quality inspectors are very important who mainly approve the work of civil engineers at construction sites. • Entire piping and ductwork are executed by mechanical engineers which are the critical part in the erection of infrastructures. • They deal with all the government approval work which involves official permission and clearances. 201 CU IDOL SELF LEARNING MATERIAL (SLM)

• Project Commissioning of the all the raw products and systems installed during the building of any plant is governed by mechanical engineers with the support of electrical engineers. • JKMEGA (Jammu and Kashmir Mechanical Engineer Graduate Associate) has appreciated the use of preventive mechanical gadgets such as motorized gates, ultrasonic level gauges which are very useful in flood control and take timely measures. 7.7 SUMMARY • The importance of the role of each of these sectors, and also their vital interlinkages, so essential for a coordinated and comprehensive disaster management system. • There is a systematic structural framework for coordination of disaster management tasks at the central, state and district levels. • The central government supplements the physical and financial resources of the state government. • The State government also invites the NGOs and relief organization to join the efforts to reach out to victims. • Pre-disaster assistance and assistance in future development tend to be of a routine nature and can be processed in a routine manner. • Assistance in response operations and recovery programmes usually has a high degree of urgency, which necessitates quick processing. • Nongovernmental organisations (NGOs) including the community-based organisations (CBOs) play an important effective role as a bridge between the government and the people. • The non-governmental sector, due to its linkages with the community base and its flexibility in procedural matters, has an advantage over governmental agencies in invoking the involvement of the people at community level. • The success of information technology in case of disaster management is hidden in the seed of communication technology such as evacuation of the people from the hazardous site, to reduce damage to the property and thus minimizing human suffering. 7.8 ABBREVIATIONS • NGO – Non-Governmental Organization • CBO – Community Based Organization • CMG – Crisis Management Group • CAP – Contingency Action Plan • IDNDR – International Decade for Natural Disaster Reduction • GIS – Geographical Information System 202 CU IDOL SELF LEARNING MATERIAL (SLM)

7.9 LEARNING ACTIVITY 1. Try to interview any government official working in the field of disaster management in your area and find out about the government's disaster management plan for your locality. Ascertain your own role as well as your neighbors’ role within the broad plan and prepare an outline of a disaster management strategy based on this information. ___________________________________________________________________________ ___________________________________________________________________________ 7.10UNIT END QUESTIONS A.Descriptive Questions Short Questions 1. What are the assistance provided by international bodies in prevention and mitigation. 2. Enumerate the assistance in recovery programmes. 3. What is Sulabh International? 4. What is the activity of NGOs during post-disaster. 5. List the phases of disaster where GIS is used. Long Questions 1. Describe the Central and State Government roles in disaster management. 2. Describe the various stages at which the international bodies provide assistance. 3. Explain the various types of NGOs. 4. Enumerate and describe the components of information technology. 5. Describe the role of various engineers on disaster management. Multiple Choice Questions 1. ______________ that facilitates the launching of relief and rescue operations without delay. a. National Contingency Action Plan b. Community Based Organization c. Crisis Management Group d. Non-Governmental Organization 2. ______________ who is in charge of the relief and rehabilitation measures of the state. a. Chief Minister b. Relief Commissioners c. Secretary d. MLA 3. Chernobyl Nuclear Power Plant Disaster occurred in the year a. 1986 b. 1970 203 CU IDOL SELF LEARNING MATERIAL (SLM)

c. 1984 d. 1990 4. _____________ may be requisitioned for distribution and more importantly in identifying the persons actually needing the relief. a. Government b. Community Based Organization c. Crisis Management Group d. Non-Governmental Organization 5. ___________________ is responsible for the construction of such high earthquake resistant buildings enhancing the infrastructure. a. Geotechnical Engineer b. Mechanical Engineer c. Electrical Engineer d. Information Technology Engineer Answer 1-a, 2-b, 3-a, 4-d, 5-a 7.11 REFERENCES Reference Books • Carter, W.N. (1991), Disaster Management; A Disaster Manager's Handbook, Asian Development Bank, Manila. • The Institution of Civil Engineers (1995), Mega Cities; Reducing Vulnerability to Natural Disasters, Thomas Telford, London. • National Centre for Disaster Management, 2001, Manual on Natural Disaster Management in India, Ministry of Agriculture, Government of India, New Delhi 204 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT-8: WASTE MANAGEMENT Structure 8.0Learning Objectives 8.1 Introduction to MSW 8.2 Waste Collection 8.3 Waste Storage 8.4 Transport 8.5 Summary 8.6 Abbreviations 8.7 Learning Activity 8.8 Questions 8.9 References 8.0 LEARNING OBJECTIVES After studying this unit students will be able to • Explain the various types of waste collection processes, storage and disposal their importance in the present scenario. • Evaluate waste management processes. 8.1 INTRODUCTION The world generates 2.01 billion tonnes of municipal solid waste annually, with at least 33 percent of that extremely conservatively not managed in an environmentally safe manner. Worldwide, waste generated per person per day averages 0.74 kilogram but ranges widely, from 0.11 to 4.54 kilograms. Though they only account for 16 percent of the world’s population, high-income countries generate about 34 percent, or 683 million tonnes, of the world’s waste. When looking forward, global waste is expected to grow to 3.40 billion tonnes by 2050, more than double population growth over the same period. Overall, there is a positive correlation between waste generation and income level. Waste from human and animal activities that are normally solid and discarded as useless or unwanted, Heterogeneous mass of throwaways from urban community and homogeneous accumulations of agricultural, industrial and mineral wastes. Organic and Inorganic waste materials such as product packaging, grass clippings, furniture, etc. produced in a society, which do not carry any value to the first user(s) is known as solid waste. Solid waste management is a term that is used to refer to the process of collecting and treating solid wastes. It also offers solutions for recycling items that do not belong to garbage or trash. As long as people have been living in settlements and residential areas, garbage or solid waste has been an issue. Waste management is all about how solid waste can be 205 CU IDOL SELF LEARNING MATERIAL (SLM)

changed and used as a valuable resource. In this chapter we will study importance of solid waste management in various processes like waste collection, storage and disposal. 8.2 WASTE COLLECTION Waste collection is a part of the process of waste management. It is the transfer of solid waste from the point of use and disposal to the point of treatment or landfill. It is otherwise said as gathering or picking up of solid wastes from various sources, loading the wastes into collection vehicles, hauling of these wastes to the location where the contents of the container vehicles are emptied and unloading of collection vehicle Collection components Collection points – influences crew size and storage Collection frequency – climatic conditions, requirements of a locality, containers and costs determine the collection frequency Storage containers – efficient, convenient, compatible, public health & safety Collection crew – optimum crew size depends on the size and type of collection vehicle, space between houses, waste generation rate and collection frequency, labour and equipment cost, collection methods and route characteristics Collection route – consider the route that is efficient for collection Transfer station – is an intermediate station between final disposal option and collection point in order to increase the efficiency of the system Methods of Residential and Commercial waste Collection 1. Collection of unseparated (commingled) wastes From low rise detached dwellings Manual methods used for the collection of residential wastes include: ▪ The direct lifting and carrying of loaded containers to the collection vehicle for emptying ▪ The rolling of loaded containers on their rims to the collection vehicle for emptying ▪ The use of small lifts for rolling loaded containers to the collection vehicle The most common types of residential collection services for low rise detached dwellings include • Curb:home owner is responsible for placing the containers to be emptied at the curb on collection day and for returning the empty containers • Alley:the containers are placed at the alley line from where they are picked up by workmen from refuse vehicles who deposit back the empty container 206 CU IDOL SELF LEARNING MATERIAL (SLM)

• Setout- setback: containers are set out from the house owner’s property and set back after being emptied by additional crews that work in conjunction with the collection crew responsible for loading the collection vehicle • Setout: house owner is responsible for returning the containers to their storage location Where mechanically loaded collection vehicles are used, the container used for the onsite storage of waste must be brought to the curb or other suitable collection site From high rise apartments • Large containers are used to collect wastes from large apartment building • Contents of the containers are emptied mechanically using collection vehicles equipped with unloading mechanisms or the loaded containers may be hauled to an off-site location where the contents are unloaded From commercial / industrial facilities 207 CU IDOL SELF LEARNING MATERIAL (SLM)

• Both manual and mechanical means are used to collect wastes from commercial facilities • To avoid traffic congestion - solid wastes are collected in the late evening and early morning hours • Where manual collection is used, wastes are put into plastic bags, cardboard boxes and other disposable containers that are placed on the curb for collection • Waste collection is usually accompanied with three or in some cases four-person crew, consisting of a driver and two / three collectors who load the wastes from the curb side into the collection vehicles 2. Collection of segregated (recyclables) wastes • Curb side collection using conventional and specially designed collection vehicles • Types of collection vehicles: standard compactor trucks, mobile container system, modified flatbed truck, open-bin recycling truck, closed body recycling truck Types of Collection: Waste collection services are divided into primary and secondary collection: • Primary collection system consists of collection of waste from household and putting into community collection container. Primary collection refers to the process of collecting, lifting and removal of segregated solid waste from source of its generation (including households, shops, offices, markets, hotels, institutions, etc.) and taking the waste to a storage depot or transfer station or directly to the disposal site, depending on the size of the city and the waste management system prevalent in the city. Vehicle typically used for primary collection: o Handcarts or tricycles with containers or bins o Tricycles with hydraulic tipping containers o Light commercial vehicles (mini trucks) with hydraulic tipping containers o Four-wheeled mini trucks with international standard garbage collection bins 208 CU IDOL SELF LEARNING MATERIAL (SLM)

• Secondary collection includes picking up waste from community bins, waste storage depots, or transfer stations and transporting it to waste processing sites or to the final disposal site. Vehicles typically used for Secondary Transportation of Wastes • Skip truck (dumper placer) • Refuse collector without compactor • Rear loading compactor truck (refuse compactor) • Light commercial vehicle with tipping floor • Hook loader or hook lifter • Non-Renewable Resources Types of collection systems Hauled container systems (HCS) • The containers used for the storage of wastes are hauled to the disposal site, emptied and returned to either their original location or some other location • Ideally suited for the removal of wastes from sources where the rate of generation is high, because relatively large containers are used • Use of large containers reduces handling time as well as the unsightly accumulations and unsanitary conditions associated with the use of smaller containers • Because containers used in this system must be filled manually, the use of very large containers often leads to low-volume utilization unless loading aids, such as platforms and ramps are provided 209 CU IDOL SELF LEARNING MATERIAL (SLM)

(b) Exchange mode 210 CU IDOL SELF LEARNING MATERIAL (SLM)

Stationary container systems (SCS) • The containers used for the storage of wastes remain at the point of generation, except when they are moved to the curb or other location to be emptied • The systems vary according to the type and quantity of wastes to be handled, as well as the number of generation points • Two main types: Systems in which mechanically loaded collection vehicles are used Systems in which manually loaded collection vehicles are used • Because of economic advantages, all the collection vehicles now used are equipped • with internal compaction mechanisms 211 CU IDOL SELF LEARNING MATERIAL (SLM)

Collection Routes Once equipment and labour requirements have been determined, collection routes must be laid out so that both the collectors and equipment are used effectively Heuristic guidelines for laying out routes: • Existing policies and regulations related to such items as the point of collection and frequency of collection must be identified • Existing system characteristics such as crew size and vehicle types must be coordinated 212 CU IDOL SELF LEARNING MATERIAL (SLM)

• Wherever possible, routes should be laid out so that they begin and end near arterial streets, using topographical and physical barriers as route boundaries • In hilly areas, routes should start at the top of the grade and proceed downhill as the vehicle becomes loaded • Routes should be laid so that the last container to be collected on the route is located nearest to the disposal site • Wastes generated at traffic congested locations should be collected as early in the day as possible • Sources at which extremely large quantities of wastes are generated should be serviced during the first part of the day • Scattered pickup points (where small quantities of solid wastes are generated) that receive the • same collection frequency should, if possible, be serviced during one trip or on the same day 8.3 WASTE STORAGE Storage of waste at source is the first essential step of Solid Waste Management. Every household, shop and establishment generate solid waste on day-to-day basis. The waste should normally be stored at the source of waste generation till collected for its disposal. In India, such a habit has not been formed and in the absence of system of storage of waste at source, the waste is thrown on the streets, treating streets as receptacle of waste. If citizens show such apathy and keep on throwing waste on streets and expect that municipal sweepers should/would clean the city, the cities will never remain clean. Even iflocal bodies make arrangements to remove all the waste disposed of by the citizens on the street on day-to- day basis, the city will remain clean only for two to three hours and not beyond till the habit of throwing waste on the streets is not changed. There is, therefore, a need to educate the people to store waste at source, dispose of the waste as per the directions of the local bodies and effectively participate in the activities of the local bodies to keep the cities clean. System of storage of waste at source, wherever practiced, by and large, does not synchronize with the system of primary collection with the result the waste stored at homes, shops and establishments in domestic, trade or institutional bins also finds its way on the street resulting in unhygienic conditions on streets. Some types of receptacles presently used for storage areas under: • Buckets • Plastic bins • Plastic bags • Metal bins with or without lids 213 CU IDOL SELF LEARNING MATERIAL (SLM)

The large such bins used without lids are unsuitable for storage of food waste for 24 hours and more in the Indian conditions as waste starts stinking very fast due to putrefaction. Storage of waste at source 1. Household-level Storage of Segregated Waste • At the household level, dry waste, wet waste, and domestic hazardous waste should be stored in separate garbage bins, of appropriate capacity and color • The color of the garbage bins should be in accordance with the SWM Rules, 2016 • – Covered Green Bin: Wet waste • – Covered White Bin: Dry waste • – Covered Black Bin: Domestic Hazardous Waste • Capacity of bins depends on frequency of collection (daily, alternate day, or on demand) and quantity of waste generated • Number and capacity of bins required depends on the quantity of waste to be stored before collection, plus an additional 100% storage to avoid spillage in case of collection delays 2. On-site Storage of Bulk Wastes • “Bulk Waste Generator” means and includes buildings occupied by the Central government departments or undertakings, State government departments or undertakings, local bodies, public sector undertakings or private companies, hospitals, nursing homes, schools, colleges, universities, other educational institutions, hostels, hotels, commercial establishments, markets, places of worship, stadia and sports complexes having an average waste generation rate exceeding 100kg per day • Number and capacity of bins required may be computed by considering quantity of waste to be stored before collection plus an additional 100% storage • Storage bins should be compatible with the primary collection system to avoid multiple handling of waste 3. Storage of Municipal Solid Waste in Public Places or Parks • With a view to ensure that streets and public places are not littered with waste, litter bins may be provided at important streets, markets, public places, tourist spots, bus and railway stations, large commercial complexes, etc. • Adequate number of bins at optimum distance (25–250 m) should be placed at public places to avoid littering • The collection from these bins should be segregated into wet and dry waste Storage Containers / Bins • The desirable characteristics of a well-designed container are low cost, size, weight, shape, resistance to corrosion, water tightness, strength and durability 214 CU IDOL SELF LEARNING MATERIAL (SLM)

• For example, a container for manual handling by one person should not weigh more than 20kg, lest it may lead to occupational hazards such as muscular strains • Containers that weigh more than 20kg when full, require two or more crew members to manually load and unload the wastes, and which result in low collection efficiency • Containers should not have rough or sharp edges and preferably have a wheel to facilitate mobility • They should be covered to prevent rainwater from entering (which increases the weight and rate of decomposition of organic materials) into the solid wastes • The container body must be strong enough to resist and discourage stray animals and scavengers from ripping it as well as withstand rough handling by the collection crew and mechanical loading equipment • Containers should be provided with a lifting bar, compatible with the hoisting mechanism of the vehicle • The material used should be light, recyclable, easily molded and the surface must be smooth and resistant to corrosion Factors to be considered in the on-site storage of solid wastes • The effect of storage on the waste components • Biological decomposition • Absorption of fluids • Contamination of waste components • The type of containers to be used • the characteristics and types of solid wastes to be collected • the type of collection systems in use • the collection frequency • the space available for the placement of containers • Container location Container storage locations depend on the type of dwelling or commercial and industrial facilities, the available space and access to collection services ▪ Residential dwellings • Low-rise detached dwellings – at the sides or rear of the house, in alleys, where alley collection is used, in or next to the garage • Low and medium rise buildings – basement storage and outdoor storage • Large high-rise apartments – basement of the building ▪ Commercial and Industrial Facilities • The siting of containers at existing commercial and industrial facilities depends on both the location of available space and service-access conditions ▪ Public health and aesthetics • Public health concerns are primarily related to the infestation of the areas with vermin and insects that often serve as potential disease vectors 215 CU IDOL SELF LEARNING MATERIAL (SLM)

• Most effective control measure for both rats and flies is proper sanitation • Proper sanitation involves the use of containers with tight lids, periodic washing of the containers as well as of the storage areas and the periodic removal of biodegradable materials • Aesthetic considerations are related to the production of odors and the unsightly conditions that can develop • Most odors can be controlled through the use of containers with tight lids and with the maintenance of a reasonable collection frequency • If odor persists, the contents of the container can be sprayed with a masking deodorant as a temporary expedient • To maintain aesthetic conditions, the container should be scrubbed and washed periodically 8.4 TRANSPORT The transportation of waste is the movement of waste over a specific area by trains, tankers, trucks, barges, or other vehicles. The types of wastes that may be transported range from municipal garbage to radioactive or hazardous wastes. Transfer and transport operations are also used in conjunction with MRFs to transport recovered materials to markets or waste-to-energy facilities and to transport materials to landfills. Today, with rising labor, operating, and fuel costs and the absence of nearby solid waste disposal sites, transfer stations are becoming common. Need for Transfer operations • Transfer and transport operations become a necessity when • Haul distances to available processing centres or disposal sites increase so that direct hauling is no longer economically feasible • Processing centres or disposal sites are sited in remote locations and cannot be reached directly by highway • Transfer operations are an integral part of all types of MRFs 216 CU IDOL SELF LEARNING MATERIAL (SLM)

Factors that make the use of transfer operations attractive: • Occurrence of illegal dumping due to excessive haul distances • Location of disposal sites relatively far from collection routes • Use of small-capacity collection vehicles • Existence of low-density residential service areas • Use of a hauled container system with relatively small containers for collection of wastes from commercial sources • Use of hydraulic or pneumatic collection systems Types of Transfer Station Transfer stations are used to accomplish transfer of solid wastes from collection and other small vehicles to larger transport equipment. Depending on the method used to load the transport vehicles, transfer stations may be classified into three general types: • Direct-load • Storage-load • Combined direct-load and discharge-load Direct-Load Transfer Stations • At direct-load transfer stations, the wastes in the collection vehicles are emptied directly into the vehicle to be used to transport them to a place of final disposition or into facilities to compact the wastes into transport vehicles or into waste bales that are transported to the disposal site • In some cases, the wastes may be emptied onto an unloading platform and then pushed into the transfer vehicles, after recyclable materials have been removed • The volume of the waste that can be stored temporarily on the unloading platform is defined as the surge capacity or the emergency storage capacity of the station Storage-load • In the storage-load transfer station, wastes are emptied directly into a storage pit from which they are loaded into transport vehicles by various types of auxiliary equipment • The difference between a direct-load and a storage-load transfer station is that the latter is designed with a capacity to store waste (typically 1-3 days) • Large-capacity direct-load transfer station without compaction 217 CU IDOL SELF LEARNING MATERIAL (SLM)

• Medium-capacity storage-load transfer station with processing and compaction facilities Combined direct-load and discharge-load • In some transfer stations, both direct-load and discharge-load methods are used • Usually these are multipurpose facilities that service a broader range of users than a single purpose facility • A multipurpose transfer station can also house a materials recovery operation Factors affecting the selection of Transfer Stations • Type of wastes received • Processes required in recovering material from wastes • Required capacity and amount of waste storage desired • Types of collection vehicles using the facility • Types of transfer vehicles that can be accommodated at the disposal facilities • Site topography and access Factors affecting the capacity of Transfer Stations • Capacity of collection vehicles using the facility • Desired number of storage space on tipping floor • Time required to unload collection vehicles • Number of vehicles that will use the station and their expected days and hours of arrival • Waste sorting or processing to be accomplished at the facility • Transfer trailer capacity 218 CU IDOL SELF LEARNING MATERIAL (SLM)

• Hours of station operation • Availability of transfer trailers waiting for loading • Time required, if necessary, to attach and disconnect trailers from tractors or compactors Transfer station design requirements The important factors that must be considered in the design of transfer stations include: • The type of transfer operation to be used • Storage and throughput capacity requirements • Equipment and accessory requirements • Sanitation requirements Location of Transfer Stations Whenever possible, transfer stations should be located: • As near as possible to the weighted centre of the individual solid waste production areas to be served • Within easy access of major arterial highway routes as well as near secondary or supplementary means of transportation • Where there will be a minimum of public and environmental objection to the transfer operations • Where construction and operation will be most economical 8.5 SUMMARY • The world generates 2.01 billion tonnes of municipal solid waste annually, with at least 33 percent of that extremely conservatively not managed in an environmentally safe manner • Solid waste management is a term that is used to refer to the process of collecting and treating solid wastes • Waste collection is a part of the process of waste management. It is gathering or picking up of solid wastes from various sources, loading the wastes into collection vehicles, hauling of these wastes to the location where the contents of the container vehicles are emptied and unloading of collection vehicle • In manual method of collection direct lifting, carrying, rolling and use of small lifts for rolling are included in the process and for mechanical loading containers are brought to the collection site for loading • Primary collection refers to the process of collecting, lifting and removal of segregated solid waste from source of its generation 219 CU IDOL SELF LEARNING MATERIAL (SLM)

• Secondary collection includes picking up waste from community bins, waste storage depots, or transfer stations and transporting it to waste processing sites or to the final disposal site. • The containers used for the storage of wastes are hauled to the disposal site, emptied and returned to either their original location or some other location is hauled container system • The containers used for the storage of wastes remain at the point of generation, except when they are moved to the curb or other location to be emptied is stationary container system • Storage of waste at source is the first essential step of Solid Waste Management. The waste should normally be stored at the source of waste generation till collected for its disposal. • The transportation of waste is the movement of waste over a specific area by trains, tankers, trucks, barges, or other vehicles • At direct-load transfer stations, the wastes in the collection vehicles are emptied directly into the vehicle to be used to transport them to a place of final disposition or into facilities to compact the wastes into transport vehicles or into waste bales that are transported to the disposal site • In the storage-load transfer station, wastes are emptied directly into a storage pit from which they are loaded into transport vehicles by various types of auxiliary equipment. 8.6 ABBREVIATIONS • MSW – Municipal Solid Waste • SWM – Solid Waste Management • HCS – Hauled container systems • SCS – Stationary Container System • MRF – Material Recovery Facility 8.7 LEARNING ACTIVITY 1. Confer about how the SWM are important to the Natural resources in current situation, also discuss about the management processes in collection, storage and transport of waste and give solutions for recycling items. ___________________________________________________________________________ ___________________________________________________________________________ 8.8UNIT END QUESTIONS A. Descriptive Questions 220 CU IDOL SELF LEARNING MATERIAL (SLM)

Short Questions 1. State the role of individual in management of waste. 2. Compare the operation of hauled container system and stationary container system of waste collection? 3. What are the various onsite storage methods? 4. Briefly explain the need and types of transfer stations. 5. Discuss the factors affecting the selection and capacity of transfer stations Long Questions 1. Discuss the following with respect to solid waste management: Reducing, Reusing, Recycling, and Recovering 2. Evaluate the collection and transfer operations in Indian cities. 3. Discuss the methods of residential and commercial waste collection systems 4. Explain the routing guidelines to formulate a suitable route for collection vehicles. 5. How will you analyze the waste collection operations? B. Multiple Choice Questions 1. Choose the optimum distance of placement of bins in public places to avoid littering. a. 20m - 200m b. 25m - 250m c. 20m - 250m d. 25m - 200m 2. Gravity Chutes are used in ________building/areas. a. Low rise b. High rise c. Treatment plant d. Agricultural 3. Identify the undesirable characteristic of storage container. 221 a. Water tightness b. Low cost c. Durable d. Sharp edge 4. Which of the integrated waste management is reduced on an individual level? a. Source reduction CU IDOL SELF LEARNING MATERIAL (SLM)

b. Recycling c. Disposal d. Burning 5. Centralized facility, where waste in unloaded from smaller collection vehicle and re-loaded into large one for transport to a disposal or processing site is a. Collection point b. Processing station c. Transfer station d. Disposal site Answer 1-b, 2-b, 3-d, 4-a, 5-c 8.9 REFERENCES References Books • George waste generation et.al, “Integrated Solid Waste Management”, McGraw-Hill Publishers, 2014 • Landreth and Rebers.P.A, “Municipal Solid Wastes– problems and Solutions”, Lewis Publishers, 2019. • Bilitewski.B, HardHe.G, Marek.K, Weissbach.A, & Boeddicker.H, “Waste Management”, Springer, 2004. 222 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT 9- WASTE DISPOSAL Structure 9.0 Learning Objectives 9.1 Introduction 9.2 Key Issues and Features 9.3 Waste Disposal Methods 9.4 Waste Processing Technique 9.5 Source Reduction 9.5.1 Purpose of Source Reduction 9.5.2 Advantages of Source Reduction 9.5.3 Activities to Encourage Source Reduction 9.6 Processing and Recovery Methods 9.6.1 Size Reduction 9.6.2 Size Separation 9.6.3 Density Separation 9.6.4 Densification 9.7Recycling Programme 9.7.1 Processing Equipment for Recycling 9.8 Case Study: Source Reduction and recycling in Bangalore 9.9 Summary 9.10 Abbreviations 9.11 Learning Activity 9.12Unit end Questions 9.13 References 9.0 LEARNING OBJECTIVES After studying this unit students will be able to • Discuss the significance of waste recycling. • plan a recycling programme. • Explain the constraints involved in the implementation of reducing and recycling programmes 9.2 INTRODUCTION Disposal/ Processing is the final element in the SWM system. It is, essentialto have a proper plan for the recovery of conversion products/energy and disposal of rejects. An efficient SWM system must provide an environmentally sound disposal option for waste that cannot be 223 CU IDOL SELF LEARNING MATERIAL (SLM)

reduced, recycled, composed, combusted, or processed further. Some of the options available for waste disposal are Uncontrolled dumping or non-engineered disposal, Sanitary Landfill, Composting, Incineration, Gasification, Refuse-Derived Fuel (RDF) and Pyrolysis. The relative merits and demerits of some of the options are given in Table 9.1 Table 9.1 Relative Merits of Disposal Options Disposaloption SustainabilityIndicat Non- SanitaryLa Incineration Composting or engineeredDi ndfill ✓ ✓ sposal X ✓ Volumereduction X XX X Expensive X ✓✓ ✓ ✓ ✓X Long- X ✓✓ termmaintenance ✓ ✓X By-productrecover ✓ ✓X Adaptabilitytoallwaste s Adverse environmentaleffect 9.2 KEY ISSUES AND FEATURES To achieve effective waste disposal, we must overcome the following the constraints: Municipal Capacities • With the increasing volume of waste generation, collection of wastes gets more attention than disposal. Furthermore. in India, only a few municipalities seem to have the required experience or capacity for controlled disposal. • Some municipalities may have identified disposal sites but still only few may actively manage them. In some places, contracting out waste disposal is seen as a solution. But municipalities are not equipped to deal with the problems associated with it, such as issues of privatization and monitoring of the contract. Political Commitment 224 CU IDOL SELF LEARNING MATERIAL (SLM)

• SWM is more than a technical issue, as any successful programme needs effective political and governmental support. • This is rarely a priority of government authorities, unless there is a strong and active public interest as well as international interventions. Finance and Cost Recovery • Development of a sanitary landfill site represents a major investment and it generally receives less priority over other resource demands. And, even when establishment costs are secured for a disposal site, recurrent costs to maintain it always pose problems. Technical Guidelines • Standards established for waste disposal in one country need not necessarily be appropriate for another, due to reasons such as climatic conditions, resources availability, institutional infrastructure, socio-cultural values, etc. • In the absence of adequate data and/or the means of collecting/acquiring it, officials often struggle to plan a safe and economically viable disposal option, Institutional Role and Responsibility • A disposal site may be located outside the boundary of a town and may serve more than one town. • This necessitates the co-ordination of all authorities concerned, and the roles and responsibilities of different departments need to be clearly defined and accepted by all concerned. Location • The accessibility of a disposal site, especially its distance from town, is an important factor in site selection, especially when staff and public do not have a strong incentive to use it, when compared to indiscriminate dumping. • Site selection is perhaps the most difficult stage in the development of suitable disposal option. 9.3 WASTE DISPOSAL METHODS With the help of proper frameworks and sub-frameworks, we can assess the effectiveness of each of the waste disposal options. A framework contains a list of issues and questions pertaining to the technical, institutional, financial, social and environmental features of a waste disposal system to assess the capacity of a disposal option to meet the requirements. The various disposal methods available are discussed below 225 CU IDOL SELF LEARNING MATERIAL (SLM)

Uncontrolled Dumping or Non-Engineered Disposal • As mentioned, this is the most common method being practised in many parts of the world, and India is no exception. In this method, wastes are dumped at a designated site without any environmental control. • They tend to remain there for a long period of time, pose health risks and cause environmental degradation. • Due to the adverse health and environmental impact associated with it, the non- engineered disposal is not considered a viable and safe option. Sanitary Landfill • Unlike the non-engineered disposal, sanitary landfill is a fully engineered disposal option in that the selected location or wasteland is carefully engineered in advance before it is pressed into service. • Operators of sanitary landfills can minimise the effects of leachate (i.e., polluted water which flows from a landfill) and gas production through proper site selection, preparation and management. • This particular option of waste disposal is suitable when the land is available at an affordable price and adequate workforce and technical resources are available to operate and manage the site. Composting • This is a biological process of decomposition in which organisms, under controlled conditions of ventilation, temperature and moisture, convert the organic portion of solid waste into humus-like material. • If this process is carried out effectively, what we get as the final product is a stable, odour -free soil conditioner. • Generally, the option of composting is considered, when a considerable amount of biodegradable waste is available in the waste stream and there is use or market for composts. • Composting can be either centralised or small-scale. Centralised composting plants are possible, if adequate skilled workforce and equipment’s are available. And, small-scale composting practices can be effective at household level, but this needs public awareness. Incineration • This refers to the controlled burning of wastes, at a high temperature (roughly 1200 – 1500OC), which sterilises and stabilises the waste in addition to reducing its volume. • In the process, most of the combustible materials (i.e., self-sustaining combustible matter, which saves the energy needed to maintain the combustion) such as paper or plastics get converted into carbon dioxide and ash. 226 CU IDOL SELF LEARNING MATERIAL (SLM)

• Incineration may be used as a disposal option, when land filling is not possible and the waste composition is highly combustible. • An appropriate technology, infrastructure and skilled workforce are required to operate and maintain the plant. Gasification • This is the partial combustion of carbonaceous material (through combustion) at high temperature (roughly 1000OC) forming a gas, comprising mainly carbon dioxide, carbon monoxide, nitrogen, hydrogen, water vapour and methane, which can be used as fuel. Refuse-Derived Fuel (RDF) • This is the combustible part of raw waste, separated for burning as fuel. Various physical processes such as screening, size reduction, magnetic separation, etc., are used to separate the combustibles. Pyrolysis • This is the thermal degradation of carbonaceous material to gaseous, liquid and solid fraction in the absence of oxygen. This occurs at a temperature between 200 O C and 900O C. 9.4 WASTE PROCESSING TECHNIQUE The processing of wastes helps in achieving the best possible benefit from every functional element of the solid waste management (SWM) system and, therefore, requires proper selection of techniques and equipment for every element. Accordingly, the wastes that are considered suitable for further use need to be paid special attention in terms of processing, in order that we could derive maximum economic value from them. Mechanical Volume and Size Reduction • The main purpose of volume and size reduction is to reduce the volume (amount) and size of waste, as compared to its original form, and produce waste of uniform size. • Compactors are used to reduce the volume of wastes. Specialized compaction equipment’s are used to compress solid wastes into blocks or bales of various sizes in high pressure compactors. • Size reduction helps in obtaining the final product in a reasonably uniform and considerably reduced size in comparison to the original form. But size reduction does not necessarily imply volume reduction, and this must be factored into the design and operation of SWM systems as well as in the recovery of materials for reuse and conversion to energy. 227 CU IDOL SELF LEARNING MATERIAL (SLM)

• In the overall process of waste treatment and disposal, size reduction is carried out ahead of land filling, recovery of materials for recycling, baling of wastes, incineration, drying and dewatering of wastes etc. Table 9.2 Size Reduction Equipment’s Type Modeofaction Application Smallgrinders Chippers Grinding,mashing Organicresidentialsolidwastes Largegrinders Cutting,slicing Paper,cardboard,treetrimmings,yardwaste ,wood,plastics Jawcrushes Raspmills Grinding,mashing Brittleandfriablematerials,usedmostlyinin Shredders dustrialoperation Cutters,Clippers Hammermills Crushing,breaking Largesolids Hydro pulper Shredding,tearing Moistenedsolidwastes Shearing,tearing Alltypesofmunicipalwastes Shearing,tearing Alltypesofmunicipalwastes Breaking,tearing,cutti All types of municipal wastes, most ng,crushing commonly usedequipmentforreducingsizeandhomog enizingcompositionofwastes Shearing,tearing Ideallysuitedforusewithpulpablewastes,in cluding paper, wood chips, Used primarily in thepapermaking industry.Also used to destroy paperrecords. • Out of these, the most frequently used shredding equipment’s are Hammer mill and Hydro pulper. • There are also chemical processes wherein volume reduction occurs through chemical changes brought within the waste either through an addition of chemicals or changes in temperature. • Incineration is the most common method used to reduce the volume of waste chemically, and is used both for volume reduction and power production. • The other chemical methods used to reduce volume of waste chemically include Pyrolysis, Hydrolysis and chemical conversions. • Prior to size or volume reduction, component separation is necessary to avoid the problem of segregating or sorting recyclable materials from the mixed and compressed 228 CU IDOL SELF LEARNING MATERIAL (SLM)

lumps of wastes and the poor quality of recyclable materials sorted out of compaction vehicles. 9.5 SOURCE REDUCTION • Source reduction, also known as waste prevention, is an approach that precedes waste management and addresses how products are manufactured and, purchased. • It refers to the activities that reduce the amount of waste generated at source as well as activities that involve any change in the design, manufacture, purchase or usage of materials/products to reduce their volume and/or toxicity, before they become part of the solid waste stream • Waste minimisation includes activities that reduce waste generated as a result of product creation and use. It also encompasses those activities that increase product durability, reusability and reparability 9.5.1 Purpose of Source Reduction • Product reuse: Using reusable products. E.g., Reusable shopping bag. • Material volume reduction: Reducing the volume of material. E.g., Buying in bulk or using large food containers reduces the amount of packaging waste generated. • Toxicity reduction: Reducing the number of toxic constituents in products entering the waste stream and reduces the adverse environmental impacts of recycling or other waste management activities. E.g., Substitution of lead and cadmium in inks (solvent-based to water based) and paints is a source reduction activity. • Increased product lifetime: Source reduction facilitates the use of products with longer lifetime over short-lived alternatives that are designed to be discarded at the end of their useful lives. Manufacturing long-life tyres is a good example of increasing product lifetime. • Decreased consumption: This refers to the reduced consumption of materials that are not reusable (e.g., using a reusable shopping bag instead of picking up plastic bags from the store). 9.5.2 Advantages of Source Reduction • Reduction in extent of environmental impacts • Reduction in resource consumption and generation of pollution • It includes producer, consumer, prudent and efficient activities 229 CU IDOL SELF LEARNING MATERIAL (SLM)

9.5.3 Activities to Encourage Source Reduction • Education and Research • Financial incentives – Tax credit or exemption – Waste disposal charges can be based on number of garbage cans used, number of bags collected • Regulation – Quality control regulation – Product design regulation 9.6 PROCESSING AND RECOVERY METHODS Methods used for the processing and the recovery of individual waste components from MSW • Size reduction • Size separation • Density separation • Electric and Magnetic Field Separation • Densification • Materials handling 9.6.1 Size Reduction • Size reduction is the unit operation used to reduce the size of the materials in MSW • It is used to process materials for direct use, such as mulch or compost, compost, or as part of a materials recovery facility • Types of equipment: 1. Hammer mill, which is very effective with brittle materials 2. Shear shredder, which uses two opposing counter rotating blades to cut ductile materials in a scissor like action 3. Tub grinder, which is widely used in the processing of yard wastes 9.6.2 Size Separation • Size separation or screening involves the separation of a mixture of materials into two or more portions be means of one or more screening surfaces. • Size separation can be accomplished dry or wet, with the former being most common in solid waste processing systems • Screens have been used before and after shredding and after air classification in the processing of refuse-derived fuel (RDF) 230 CU IDOL SELF LEARNING MATERIAL (SLM)

Types of Equipment: – Reciprocating screens – for sizing shredded yard wastes – Trommel screens – for preparing commingled MSW prior to shredding – Disc screens – for removing glass from shredded MSW 9.6.3 Density Separation • Density separation is a technique widely used to separate materials based on their density and aerodynamic characteristics • Density separation has been applied to the separation of shredded MSW into two major components: – The light fraction, fraction, composed primarily of paper, plastics, plastics, and organics – The heavy fraction, which contains metals, wood and other relatively dense inorganic materials • Types of Equipment: – Air classifiers – for preparation of RDF – Inertial separators – for the processing of commingled MSW – Flotation– for the processing of construction debris 9.6.4 Densification • Densification (also known as compaction) is a unit operation that increases the density of waste materials so that they can be stored and transported more efficiently and as a means of preparing densified refuse-derived fuels 9.7 RECYCLING PROGRAMME • Recycling is one of the fundamental parts of the waste management plan. Recycling has a lot of direct significance for the society such as (i) Economic significance which includes cost reduction, employment generation, energy saving, reduced health care costs etc., (ii) Environmental and health significance such as improved environment, natural resources conservation etc., and (iii)Social significance. • The recycling of waste will increase the economic value of the waste and will reduce quantum of waste to be disposed. • The major components of recycling programme are: Source separation is an important activity in any recycling programme and it refers to the segregation of the recyclable 231 CU IDOL SELF LEARNING MATERIAL (SLM)

and reusable materials at the source of generation. This requires separation of different components in different containers. • In some places, a well-planned programme for collection of recyclable materials is in place like Drop-off programme and Buy-back programme. • A drop- off programme requires resident to separate the recyclable materials and bring them to a specified drop off or collection. • Buy- back refers to a drop- off programme that provides monetary incentives to participate. In this type of programme, the resident is paid back for their recyclable material directly or indirectly through the reduction in collection and disposal fees. • Collection vehicles that are designed specifically for collecting recyclables have several storage bins, which can be easily loaded and often equipped with automatic container- tipping devices. 9.7.1 Processing Equipment for Recycling Recycling involves a number of processing techniques and these processes require different equipment’s such as: Balers: Balers can be used to reduce the volume of many types of materials including paper, cardboard, plastics and cans. Balers can improve space utilization and reduce material transportation costs. Can densifiers: Can crushers are used to reduce the volume of aluminum and steel cans prior to transport. Glass crushers: These are used to process glass fraction separated by colour and break it into small pieces. This crushed material is then called cullet, and can be reprocessed into new glass products. Magnetic separators: These are used to remove ferrous material from a mixture of materials. Wood grinders: These are chippers and are used to shred large pieces of wood into chips that can be used as much or as fuel. 9.8 CASE STUDY: SOURCE REDUCTION ANDRECYCLING IN BANGALORE • Source reduction, including reuse and recycling, can help reduce waste disposal and handling costs, because it avoids the costs of municipal composting, landfilling and combustion. • Source reduction also conserves resources and reduces pollution, including greenhouse gases that contribute to global warming. Waste reduction, reuse and recycling, thus, play an important role in SWM. 232 CU IDOL SELF LEARNING MATERIAL (SLM)

• In what follows, we present thestatistics on waste recovery and recycling done in Bangalore, India. In Bangalore, 66% of the waste generated is collected for recovery, i.e., about 2,373 tonnes per day. • While 722 tonnes per day is reused, the rest (i.e., 1,450 tonnes) goes for recycling. The agents involved in the collection and recovery of wastes in the city include waste pickers, IWB (i.e., itinerant waste buyer), middlemen (or intermediaries), the municipality and recycling units (both large and small). • While the three agents in the informal sector and the municipality are directly involved in waste collection activities, the waste is processed by the recycling units, which receive recyclable waste from middlemen and municipality. : Table 9.3 Waste Recovery and Collection by Stakeholders Stakeholders For reuse For recycling IWB Intermediaries Households 101.7 Waste pickers 60.4 57.7 Commercial 350.8 0.0 24.3 establishments 112.7 74.5 0.0 8.8 markets 227 200 hotels 238.1 27 0.0 15.4 Institutes 0.0 9.6 0.0 61.3 hospitals 0.0 1.0 0.0 0.0 offices 0.0 8.4 0.0 0.0 educational 0.0 0.2 0.0 61.3 institutions Industries 269.3 0.8 0.0 934.5 721.8 312 60.4 1077.8 Total Of the 1450 tonnes collected for recycling, 1077.8 tonnes come from intermediaries, 60.4 tonnes come from IWB and 312 tonnes come from waste pickers. This amounts to 40% of the total waste (i.e., 3613 tonnes per day) generated. 233 CU IDOL SELF LEARNING MATERIAL (SLM)

9.9 SUMMARY • Source reduction, also known as waste prevention, is an approach that precedes waste management and addresses how products are manufactured and, purchased. • Disposal/ Processing is the final element in the SWM system. It is, essentialto have a proper plan for the recovery of conversion products/energy and disposal of rejects. • Pyrolysis is the thermochemical decomposition of organic material at elevated temperatures in the absence of oxygen. It involves the simultaneous change of chemical composition and physical phase and is irreversible. • As proper treatment such as implementing the ground improvement techniques the landfill site can used for small construction. • Sanitary landfill, which is the controlled disposal of waste on the land is well suited to developing countries. It controls the exposure of the environment and humans to detrimental effects of solid waste placed on the land. • Residual inert wastes at the end of the hierarchy are to be disposed in sanitary lined landfills, which are constructed in accordance with stipulations. • In waste management hierarchy, composting is considered as an organic material recovery process and is often considered at the same hierarchical level as inorganic waste recycling. • Landfills which integrate the capture and use of methane are preferred over landfills which flare landfill gas. The least preferred option is to dispose waste in landfills. • Source separation refers to the segregation of the recyclable and reusable materials at the point of generation. Source separation may be voluntary or mandated and is done in conjunction with several recycling programs. 9.10 ABBREVIATIONS • MSW – Municipal Solid Waste • SWM – Solid Waste Management • RDF – Refuse Derived Fuel 9.11 LEARNING ACTIVITY 1. Explain the recycling program elements adopted in your locality. ________________________________________________________________________ ___ ___________________________________________________________________________ 9.12UNIT END QUESTIONS A. Descriptive Questions 234 CU IDOL SELF LEARNING MATERIAL (SLM)

Short Questions 1. What is disposal? 2. List the various disposal options of solid wastes 3. What is a sanitary landfill? 4. Outline the requirements for a landfill. 5. What do you understand by source reduction of solid wastes? Long Questions 1. Discuss the purpose of source reduction of solid wastes. 2. What do you understand by ‘Processing and Recovery’? 3. Discuss in detail about recycling and mention the advantages of recycling of wastes. 4. Discuss in detail about the Waste Processing Techniques 5. Briefly explain the techniques and equipment used for resource recovery from solid wastes. B.Multiple Choice Questions 1. Problem of solid waste disposal can be reduced through a. Recycling b. Lesser pollution c. More timber d. Population control 2. The process of transforming segregated solid waste into a new product or a raw material for producing new products is termed as a. Reusing b. Recovering c. Recycling d. Repairing 3. From the environmental aspect, recycling is important because of a. Livelihood opportunities for recyclers b. Unsustainable use of resources c. Reduction of imports of raw materials d. Reduced waste volume and hence reduced land requirement for disposal 4. Calendaring is a process related to a. Cardboard recycling b. Glass recycling c. Metal recycling d. Plastic recycling 235 CU IDOL SELF LEARNING MATERIAL (SLM)

5. Pick the statement that is not true about full stream processing. a. It is a high technology separation technique, which processes all components ofmunicipal waste stream processing b. This technique remains attractive because it requires source separation c. The materials recovered by this process tend to be of lower quality d. To achieve a better quality, the materials obtained through the full streamprocessing must be cleaned Answer 1-a, 2-c, 3-d, 4-a, 5-b 9.13 REFERENCES Reference Books • George Tchobanoglous et.al, “Integrated Solid Waste Management”, McGraw-Hill Publishers, 2003 • Landreth.R. E and Rebers.P. A, “Municipal Solid Wastes– problems and Solutions”, Lewis Publishers, 2002. 236 CU IDOL SELF LEARNING MATERIAL (SLM)

UNIT-10 RECOVERY OF BIOLOGICAL CONVERSION PRODUCTS Structure 10.0 Learning Objectives 10.1 Introduction 10.2 Composts 10.3 Biogas 10.4 Composting Technologies 10.4.1 Methods of Composting 10.5Bio gasification Technologies 10.6 Hazardous Waste Management 10.6.1 Hazardous Waste Characteristics 10.6.2 Transport of Hazardous Waste 10.6.3 Treatment, Storage and Disposal 10.6.4 Remedial Actions 10.7 Integrated Solid Waste Management 10.7.1 Components of Integrated Solid Waste Management 10.7.2 The Importance of ISWM as a Waste Management Approach 10.8 Summary 10.9 Keywords 10.10 Learning Activity 10.11 Unit end Questions 10.12 References 10.0 LEARNING OBJECTIVES After Studying this unit students will be able to • Understand the various biological conversion products, their production technologies and application. • Analyze hazardous waste management and integrated waste management. 10.1 INTRODUCTION Management of solid wastes is a serious problem all over the world. The need of the hour is recovery from solid wastes rather than disposal using landfilling. The options that are commonly used are (i) first order recovery in the form of paper, plastics etc. (ii) second order recovery in the form of compost, biogas, heat recovery from incineration etc. Out of these, 237 CU IDOL SELF LEARNING MATERIAL (SLM)

recovery in the form of biogas and compost are increasing. Several studies are being taking place to expedite best recovery from solid wastes. This chapter illustrates the various processes and technology involved in the recovery of biological conversion products from municipal solid waste and landfills. 10.2 COMPOSTS • Composts are crumbly mass of rotted organic matter made from decomposed plant material, used in gardening and agriculture. • Compost is especially important in organic farming, where the use of synthetic fertilizers is not permitted. Compost improves soil structure, provides a wide range of nutrients for plants, and adds beneficial microbes to the soil. • The maximum benefits of compost on soil structure (better aggregation, pore spacing, and water storage) and on crop yield usually occur after several years of use. Figure 10.1: Farmer managing a Compost Pile in France • Composts commonly contain about 2 percent nitrogen, 0.5–1 percent phosphorus, and about 2 percent potassium. • Nitrogen fertilizers and manure may be added to speed decomposition. • The nitrogen of compost becomes available slowly and in small amounts, which reduces leaching and extends availability over the whole growing season. • Because of their fairly low nutrient content, composts are usually applied in large amounts. • Compost can be prepared on a small scale for home gardens, usually in a simple pile of yard waste and kitchen scraps, though compost bins and barrels are also used. 238 CU IDOL SELF LEARNING MATERIAL (SLM)

• Aeration is important for proper decomposition, so piles are usually mixed every few days. • When properly prepared, compost is free of obnoxious odors. • A compost pile with the right ratio of carbon to nitrogen (30:1) and with adequate moisture will produce enough heat during decomposition to kill many pathogens and seeds, though it is advisable to avoid adding diseased plant matter and weeds that have gone to seed. • Some municipalities collect household yard waste for large-scale composting, which reduces the amount of organic matter in landfills. Figure 10.2: Scraps of Plant Matter collected in a Compost Bin in a Garden. • Vermicomposting is a method of composting that utilizes earthworms. • Worms are kept in specialized bins and fed kitchen scraps and other plant matter. • After several weeks the worms are removed, and their rich castings (manure) are collected for use as a soil amendment. 10.3 BIOGAS Biogas is a naturally occurring gas that is generated by the breakdown of organic matter by anaerobic bacteria and is used in energy production. Biogas differs from natural gas in that it is a renewable energy source produced biologically through anaerobic digestion rather than a fossil fuel produced by geological processes. Biogas is primarily composed of methane gas, carbon dioxide, and trace amounts of nitrogen, hydrogen, and carbon monoxide. 239 CU IDOL SELF LEARNING MATERIAL (SLM)

It occurs naturally in compost heaps, as swamp gas, and as a result of enteric fermentation in cattle and other ruminants. Biogas can also be produced in anaerobic digesters from plant or animal waste or collected from landfills. It is burned to generate heat or used in combustion engines to produce electricity. The use of biogas is a green technology with environmental benefits. Biogas technology enables the effective use of accumulated animal waste from food production and of municipal solid waste from urbanization. The conversion of organic waste into biogas reduces production of the greenhouse gas methane, as efficient combustion replaces methane with carbon dioxide. Given that methane is nearly 21 times more effective in trapping heat in the atmosphere than carbon dioxide, biogas combustion results in a net reduction in greenhouse gas emissions. Additionally, biogas production on farms can reduce the odors, insects, and pathogens associated with traditional manure stockpiles. 10.4 COMPOSTING TECHNOLOGIES • Compost is organic matter that has been decomposed and recycled as a fertilizer and soil amendment. Compost is a key ingredient in organic farming. • Composting is the biological decomposition of biodegradable solid waste under controlled predominantly aerobic conditions to a state that is sufficiently stable for nuisance-free storage and handling and is satisfactorily matured for safe use in agriculture • Composting of waste is an aerobic (in the presence of air) method of decomposing solid wastes. The process involves decomposition of organic waste into humus known as compost which is a good fertilizer for plants. Composting Operation Modern composting operations consist of three basic steps: • Preprocessing of the MSW • Decomposition of the organic fraction of the MSW • Preparation and marketing of the final product Under ideal conditions, composting proceeds through three major phases • Mesophilic phase: An initial, mesophilic phase, in which the decomposition is carried out under moderate temperatures by mesophilic microorganisms. 240 CU IDOL SELF LEARNING MATERIAL (SLM)

• Thermophilic phase: As the temperature rises, a second, thermophilic phase starts, in which the decomposition is carried out by various thermophilic bacteria under higher temperatures (50 to 60 °C (122 to 140 °F).) • Maturation phase: As the supply of high-energy compounds dwindles, the temperature starts to decrease, and the mesophiles once again predominate in the maturation phase. Factors Influencing Composting • Particle size and particle size distribution • Seeding and mixing requirements • Required mixing / turning schedule • Total oxygen requirements • Moisture content • Temperature • Carbon-Hydrogen (C/N) ratio • pH • Degree of decomposition • Respiratory quotient • Control of pathogens Advantages of Composting • Reduces odor • Volume reduction • Nutrient concentration • May result in a marketable product • Potential income by incorporating other waste streams • Reduced pathogens • Relatively simple 10.4.1 METHODS OF COMPOSTING In-Vessel Composting • Composting accomplished inside an enclosed container or vessel is called as in-vessel composting. • The type of vessels used in this system include vertical towers, horizontal, rectangular and circular tanks, and circular rotating tanks. • It uses a controlled aeration system. 241 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 10.3: In-Vessel Composting Windrow Composting • In this technique, organic waste is placed into rows of long piles called windrows and are aerated by turning the pile periodically by either manual or mechanical methods. • The ideal pile height is approximately 4 to 8 feet and the ideal width is between 14 and 16 feet. This height allows for a pile large enough to generate sufficient heat yet small enough to allow oxygen to flow to the windrow’s core. • This method has the advantage that it is applicable to large volumes of diverse wastes, including yard trimmings, grease, liquids and animal byproducts. However, this requires frequent turning of the pile and careful monitoring. Figure 10.4: Windrow Composting 242 CU IDOL SELF LEARNING MATERIAL (SLM)

• In this method, large materials like broken glass pieces, stone, plastic articles, etc. are first removed and remaining solid waste is dumped on ground in the form of piles. • The piles are then covered with night soil, animal dung to supply necessary organisms for biodegradation • The temperature rises because of biological activities in the waste piles and microbial action shift from mesophilic to thermophilic stage. • After this pile is turned up for cooling and aeration to avoid anaerobic decomposition • The temperature of pile again rises to 75oC and process of turning, cooling and aeration are repeated. • The complete process may take 4 to 6 weeks and finally compost is ready to use as fertilizers. • Windrow composting can work in both warm, arid climates and in cold climates. • In warm, arid climates it is sometimes necessary to cover or shelter the pile to prevent water evaporation. • Rainy seasons sometimes require adjustment of the shape of the pile to ensure that the water runs off the top of the pile rather than being absorbed into the pile. • In cold climates, the pile might freeze at the outside, but will remain warm in the core. • It is important to collect and treat the leachate that is released during the composting process. Otherwise, it might contaminate local ground-water and surface-water supplies. • Windrow composting often requires large tracts of land, sturdy equipment, a continual supply of labor. • In addition, the technique requires some experimentation with various materials mixtures and turning frequencies. • The technique has the advantage that it results in large quantities of compost. Aerated Static Pile Composting • Aerated Static Pile (ASP) composting, refers to any of a number of systems used to biodegrade organic material without physical manipulation during primary composting. • The blended admixture is usually placed on perforated piping, providing air circulation for controlled aeration . It may be in windrows, open or covered, or in closed containers. • With regard to complexity and cost, aerated systems are most commonly used by larger, professionally managed composting facilities, although the technique may range from very small, simple systems to very large, capital intensive, industrial installations. • Aerated static piles offer process control for rapid biodegradation, and work well for facilities processing wet materials and large volumes of feedstocks. 243 CU IDOL SELF LEARNING MATERIAL (SLM)

• ASP facilities can be under roof or outdoor windrow composting operations, or totally enclosed in-vessel composting, sometimes referred to tunnel composting. Figure 10.5 Aerated Static Pile Composting Vermicomposting • Vermicompost (also called worm castings, worm humus, worm manure, or worm faces) is the end-product of the breakdown of organic matter by earthworms. • These castings have been shown to contain reduced levels of contaminants and a higher saturation of nutrients than the organic materials before vermicomposting. Figure 10.6: Vermicomposting 244 CU IDOL SELF LEARNING MATERIAL (SLM)

10.5 BIOGASIFICATION TECHNOLOGIES • Bio-Gasification is defined as the method of converting biomass, wastes, or other carbon-containing materials into a gas that can be burned to generate power or processed into chemicals and fuels. • Biogas can also be produced under controlled conditions in special tanks called anaerobic digesters. • Animal and plant wastes can be used to produce biogas. They are processed in anaerobic digesters as a liquid or as a slurry mixed with water. • Anaerobic digesters are generally composed of a feedstock source holder, a digestion tank, a biogas recovery unit, and heat exchangers to maintain the temperature necessary for bacterial digestion. • Anaerobic bacteria occur naturally in soils, in water bodies such as swamps and lakes, and in the digestive tracts of humans and animals. • Anaerobic decomposition of biomass occurs when anaerobic bacteria (bacteria that live without the presence of free oxygen) eat and break down, or digest biomass and produce biogas. • The material remaining after anaerobic digestion is complete is called digestate, which is rich in nutrients and can be used as a fertilizer. • Small-scale household digesters containing as little as 757 litres (200 gallons) can be used to provide cooking fuel or electric lighting in rural homes. • Millions of homes in less-developed regions, including China and parts of Africa, are estimated to use household digesters as a renewable energy source. • Large-scale farm digesters store liquid or slurried manure from farm animals. • The primary types of farm digesters are covered lagoon digesters, complete mix digesters for slurry manure, plug-flow digesters for dairy manure, and dry digesters for slurry manure and crop residues. • Heat is usually required in digesters to maintain a constant temperature of about 35 °C (95 °F) for bacteria to decompose the organic material into gas. • An efficient digester may produce 200–400 cubic metres (7,000–14,000 cubic feet) of biogas containing 50–75 percent methane per dry ton of input waste. 245 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 10.7: Simple Schematic of a Biogas Plant Biogas from Landfills • The natural decomposition of organic matter in a landfill occurs over many years, and the biogas produced (also known as landfill gas) can be collected from a series of interconnected pipes located at various depths across the landfill. • The composition of this gas changes over the life span of the landfill. Generally, after one year, the gas is composed of about 60 percent methane and 40 percent carbon dioxide. • Landfill collection varies according to the percentage of organic waste and the age of the facility, the average energy potential being about 2 gigajoules (1,895,634 BTU) per ton of waste. • Landfill gas collection systems are increasingly being implemented to prevent explosions from methane accumulation inside the landfill or to prevent the loss of methane, a greenhouse gas, into the atmosphere. • The collected gas can be burned at or near the site in furnaces or boilers, but it is instead often used in internal combustion engines or gas turbines to create electricity, given the limited need for heat production at most remote landfill locations. 246 CU IDOL SELF LEARNING MATERIAL (SLM)

Figure 10.8: Biogas Collection System in a Modern Landfill 10.6 HAZARDOUS WASTE MANAGEMENT • Hazardous-waste management is the collection, treatment, and disposal of waste material that, when improperly handled, can cause substantial harm to human health and safety or to the environment. • Hazardous wastes can take the form of solids, liquids, sludges, or contained gases, and they are generated primarily by chemical production, manufacturing, and other industrial activities. • They may cause damage during inadequate storage, transportation, treatment, or disposal operations. • Improper hazardous-waste storage or disposal frequently contaminates surface water and groundwater supplies as harmful water pollution and can also be a source of dangerous land pollution. • People living in homes built near old and abandoned waste disposal sites may be in a particularly vulnerable position. • In an effort to remedy existing problems and to prevent future harm from hazardous wastes, governments closely regulate the practice of hazardous-waste management. 247 CU IDOL SELF LEARNING MATERIAL (SLM)

10.6.1 HAZARDOUS WASTE CHARACTERISTICS Hazardous wastes are classified on the basis of their biological, chemical, and physical properties. These properties generate materials that are toxic, reactive, ignitable, corrosive, infectious, or radioactive. • Toxic wastes are poisons, even in very small or trace amounts. They may have acute effects, causing death or violent illness, or they may have chronic effects, slowly causing irreparable harm. • Some are carcinogenic, causing cancer after many years of exposure. • Others are mutagenic, causing major biological changes in the offspring of exposed humans and wildlife. • Reactive wastes are chemically unstable and react violently with air or water. They cause explosions or form toxic vapours. • Ignitable wastes burn at relatively low temperatures and may cause an immediate fire hazard. • Corrosive wastes include strong acidic or alkaline substances. They destroy solid material and living tissue upon contact. • Infectious wastes include used bandages, hypodermic needles, and other materials from hospitals or biological research facilities. • Radioactive wastes emit ionizing energy that can harm living organisms. Because some radioactive materials can persist in the environment for many thousands of years before fully decaying, there is much concern over the control of these wastes. However, the handling and disposal of radioactive material is not a responsibility of local municipal government. Because of the scope and complexity of the problem, the management of radioactive waste particularly nuclear fission waste is usually considered an engineering task separate from other forms of hazardous-waste management. 10.6.2 TRANSPORT OF HAZARDOUS WASTE • Hazardous waste generated at a particular site often requires transport to an approved treatment, storage, or disposal facility (TSDF). • Because of potential threats to public safety and the environment, transport is given special attention by governmental agencies. • In addition to the occasional accidental spill, hazardous waste has, in the past, been intentionally spilled or abandoned at random locations in a practice known as “midnight dumping.” This practice has been greatly curtailed by the enactment of laws that require proper labeling, transport, and tracking of all hazardous wastes. Transport vehicles • Hazardous waste is generally transported by truck over public highways. 248 CU IDOL SELF LEARNING MATERIAL (SLM)

• Only a very small amount is transported by rail, and almost none is moved by air or inland waterway. • Highway shipment is the most common because road vehicles can gain access to most industrial sites and approved TSDFs. • Railroad trains require expensive siding facilities and are suitable only for very large waste shipments. • Hazardous wastes can be shipped in tank trucks made of steel or aluminum alloy, with capacities up to about 34,000 litres (9,000 gallons). • They also can be containerized and shipped in 200-litre (55-gallon) drums. • Specifications and standards for cargo tank trucks and shipping containers are included in governmental regulations. 10.6.3 TREATMENT, STORAGE AND DISPOSAL Several options are available for hazardous-waste management. The most desirable is to reduce the quantity of waste at its source or to recycle the materials for some other productive use. Nevertheless, while reduction and recycling are desirable options, they are not regarded as the final remedy to the problem of hazardous-waste disposal. There will always be a need for treatment and for storage or disposal of some amount of hazardous waste. Treatment Hazardous waste can be treated by chemical, thermal, biological, and physical methods. The chemical, thermal, and biological treatment methods outlined below change the molecular form of the waste material. Chemical Treatment • Chemical methods include ion exchange, precipitation, oxidation and reduction, and neutralization. • Ion exchange is used to remove from solution ions derived from inorganic materials. The solution is passed over a resin bed, which exchanges ions for the inorganic substances to be removed. When the bed loses its capacity to remove the component, it can be regenerated with a caustic solution. • Precipitation is a process for removing soluble compounds contained in a waste stream. A specific chemical is added to produce a precipitate. This type of treatment is applicable to streams containing heavy metals. • Oxidation-reduction is a process for detoxifying toxic wastes in which the chemical bonds are broken by the passage of electronics from one reactant to another. • Neutralization is a process for reducing the acidity or alkalinity of a waste stream by mixing acids and bases to produce a neutral solution. This has proven to be a viable waste management process. 249 CU IDOL SELF LEARNING MATERIAL (SLM)

Thermal Treatment • Among thermal methods is high-temperature incineration, which not only can detoxify certain organic wastes but also can destroy them. • Special types of thermal equipment are used for burning waste in either solid, liquid, or sludge form. These include the fluidized-bed incinerator, multiple-hearth furnace, rotary kiln, and liquid-injection incinerator. • One problem posed by hazardous-waste incineration is the potential for air pollution. Biological Treatment • Treatment of certain organic wastes, such as those from the petroleum industry is done biologically. • Land farming is a method used to treat hazardous wastes. In this technique the waste is carefully mixed with surface soil on a suitable tract of land. Microbes that can metabolize the waste may be added, along with nutrients. In some cases, a genetically engineered species of bacteria is used. • Microbes can also be used for stabilizing hazardous wastes on previously contaminated sites; in that case the process is called Bioremediation. Physical Treatment • Physical treatment concentrates, solidifies, or reduces the volume of the waste. • Physical processes include evaporation, sedimentation, flotation, and filtration. • Evaporation is a process for concentrating non-volatile solids in a solution by boiling off the liquid portion of the waste stream. Evaporation units are often operated under some degree of vacuum to lower the heat required to boil the solution. • Sedimentation is a process for removing suspended solid particles from a waste stream. Sedimentation is usually accomplished by providing sufficient time and space in special tanks or holding ponds for settling. Chemical coagulating agents are often added to encourage the settling of fine particles. • Flotation is a process for removing solids from liquids by floating the particles to the surface by using tiny air bubbles. Flotation is useful for removing particles too small to be removed by sedimentation. • Filtration is a process for separating liquids and solids by using various types of porous materials. There are many types of filters designed to achieve various levels of separation. • Another process of physical treatment is Solidification, which is achieved by encapsulating the waste in concrete, asphalt, or plastic. • Encapsulation produces a solid mass of material that is resistant to leaching. Waste can also be mixed with lime, fly ash, and water to form a solid, cement like product. Surface Storage and Land Disposal 250 CU IDOL SELF LEARNING MATERIAL (SLM)