Waste Handling and Separation , Storage, and Processing at the Source Chapter 7

1. Waste Handling and Separation , Storage, and Processing at the Source Chapter 7

2. Presentation Outline • Introduction • Handling and Separation of Solid Waste at the Source • Waste Handling and Separation at the Residential Dwellings • Waste Handling and Separation at the Commercial and Industrial Facilities • Storage of Solid Waste at the Source • Processing of Solid Wastes at Residential Dwellings • Processing of Solid Wastes at Commercial and Industrial Facilities

3. Introduction • The handling and separation, storage , and processing of solid wastes at the source before they are collected is the second of the six functional elements in the solid waste management system. • because this element can have a significant effect on the characteristics on the waste, on subsequent functional elements, on public health, and on public attitudes concerning the operation of the waste management system, it is important to understand what this elements involves.

4. Handling and Separation of SW at the Source • Waste Handling • In general, Handling refers to the activities associated with managing solid wastes until they are placed in the containers used for their storage before collection or return to drop-off and recycling centers. • The specific activities associated with handling waste materials at the source of generation will vary depending on: • Types of waste materials that are separated for reuse and recycling • The extent to which these materials are separated from the waste stream • Type of collection service where handling may also be required to move the loaded containers to the collection point and to return the empty containers to the point where they are stored between collections.

5. Handling and Separation of SW at the Source • Separation for Recycling • The separation of solid waste components ( waste paper, cardboard, cans, glasses and plastic containers) at the source of generation is one of the most positive and effective ways to achieve the recovery and reuse of materials. • Some homeowners store the separated components within the home, periodically transferring the accumulated wastes to larger containers used for the storage of these materials between collection • other homeowners prefer to take separated waste components and place them directly in the containers used for the storage of these materials.

6. Waste Handling and Separation at Residential Dwellings • The three classifications most often used for the residential dwellings are: • Low rise ( under four stories) • single – family detached • single family attached • multifamily • Medium rise ( from four to seven stories) • High rise ( over seven stories) • Because of the significant differences in the solid waste handling operations for the low-rise dwellings and medium – and high –rise apartments, each is considered separately in the following discussion.

7. Waste Handling and Separation at Residential Dwellings • At Low – Rise Detached Dwellings • The residents or tenants under this category are responsible for placing the solid wastes and recyclable materials that are generated in and around their dwellings in storage containers. • In some collection systems, mixed wastes are placed in a variety of storage containers with little or no standardization. In other systems, mixed wastes are placed in large 90 –gal containers equipped with wheels. In both of these systems, the homeowners are responsible for transporting the containers filled with wastes to the street curb for collection.

8. Waste Handling and Separation at Residential Dwellings

9. Waste Handling and Separation at Residential Dwellings

10. Waste Handling and Separation at Residential Dwellings • At Low – and Medium – Rise Apartment • Handling methods in most low and medium rise apartment buildings resemble these used for low-rise dwellings, but methods may vary somewhat depending on the waste storage location and collection method. • Typical solid waste storage locations include: • Basement Storage • Outdoor Storage • Compactor Storage • Different types of non-recycling and recycling waste handling and separation for low and medium rise apartment buildings are delineated in Table 7-3.

11. Waste Handling and Separation at Residential Dwellings

12. Waste Handling and Separation at Residential Dwellings • Basement storage/Curbside Collection • Curbside collection service is common for most low-and medium – rise apartments. • Where curbside collection is used, the building owner provides a basement storage room or area for the storage of solid waste. Typically, the containers used for recycling are located within or next to the solid waste storage area • Residents carry their waste and recyclable materials to the storage area and deposit them in the appropriate containers. • The maintenance staff is responsible for transporting the containers to the street for curbside collection. Alternatively, in many apartments the maintenance staff is responsible for the collection of wastes and recyclable materials left out-side of the doorway to the apartment or from a utility room located on each floor.

13. Waste Handling and Separation at Residential Dwellings • Outdoor Storage / Mechanized Collection • Large waste storage containers are located outdoors in special closures. • The large containers are emptied mechanically using collection vehicles equipped with unloading mechanisms. • The containers used for recycling are located within the outdoor storage area or next to the waste storage area. • Residents carry their waste and recyclable materials to the storage area and deposit them in the appropriate containers. If needed, the maintenance staff is responsible for moving the containers to the collection point.

14. Waste Handling and Separation at Residential Dwellings • At High- Rise Apartments • In high –rise apartment buildings the most common methods of handling solid wastes involves one or more of the following: • Wastes are picked up by building maintenance personnel from the various floors and taken to the basement or service area • Wastes are taken to the basements or service area by tenants • Wastes, usually bagged, are placed by the tenants in specially designed vertical chutes with openings located on each floor. Wastes discharged in chutes are collected in large containers, compacted into large containers or baled directly. The entrance to the waste chute is usually located in the service area • Recyclable materials may be put outside in the hall or entry way for pickup.

15. Waste Handling and Separation at Residential Dwellings • At High- Rise Apartments • Bulky items are usually taken to the service area by tenants or the building maintenance crew • In many cases, solid waste chutes are used in conjunction with large compactors. The building maintenance personnel are responsible for handling the compressed wastes and any other waste or recyclable materials that tenants bring to the service area • Chutes for use in apartment buildings are available in diameter from 12 to 36 in. The most common chute diameter is 24 in. • All the available chutes can be furnished with suitable intake doors, either side – bottom-hinged, for installation on various floor levels

16. Waste Handling and Separation at Residential Dwellings • At High- Rise Apartments • Draft baffles at the intake doors, door locks, sprinklers, disinfection systems, sound insulation, and roof vents are among the many accessories that are available. • The use of a disinfecting and sanitizing unit is recommended because the cleanliness of the chute and the absence of odors generally depend to a large extent on their use. • In designing chutes for high rise apartment, one must consider variations in the rate at which solid waste are discharged. • In sizing chutes it is common to assume that • The bulk specific weight of the solid waste equals 175 lb/yd3 • All the daily wastes will be discharged within a 4-h period • between 1 and 2 lb of wastes will be generated by each tenant each day

17. Waste Handling and Separation at Residential Dwellings • At High- Rise Apartments • In some of the more recently constructed apartment buildings, underground pneumatic transport systems have been used in conjunction with individual apartment chutes. • The underground pneumatic systems transport waste from the chute discharge points to centralized processing facilities. Both air pressure and vacuum transport systems have been used in this application.

18. Waste Handling and Separation at Residential Dwellings

19. Waste Handling and Separation at Commercial and Industrial Facilities • Commercial Facilities • In most office and commercial buildings, solid wastes that accumulate in individual offices or work locations are collected in relatively large container mounted on rollers. • Once filled, these containers are removed by means of the service elevator and emptied into • Large storage containers • Compactors used in conjunction with the storage containers • Stationary compactors that can compress the material into bales or into specially designed containers • Other processing equipment. because many older large office and commercial buildings were designed without adequate provision for onsite storage of solid wastes and recyclable materials, the storage and processing equipment now used is often inadequate due to space limitations and tends to create handling problems

20. Waste Handling and Separation at Commercial and Industrial Facilities • Industrial Facilities • The handling and separation of nonindustrial solid wastes at industrial facilities is essentially the same as for commercial facilities. Because the handling of industrial wastes is industry and site specific, few generalization are possible.

21. Storage of Solid Waste at the Source • Factors that must be considered in the onsite storage of solid wastes include: • The effect of storage on the wastes components • The type of container to be used • Container location • Public health and aesthetic

22. Storage of Solid Waste at the Source • The effect of storage on the wastes components • Microbiological Decomposition • Food and other wastes placed in onsite storage containers will start to undergo microbiological decomposition as a result of the growth of bacteria and fungi • If waste are allowed to remain in storage containers for extended periods of time, flies can start to breed and odorous compounds can develop • Absorption of Fluids • Because the components that comprise solid wastes have differing initial moisture content, re-equilibration takes place as waste are stored onsite in containers (e.g., Paper will absorb moisture from food waste). • The degree of absorption depends on the length of time the wastes are stored until collection and the rainfall

23. Storage of Solid Waste at the Source • The effect of storage on the wastes components • Contamination of waste components • The major waste components may be contaminated by small amount of wastes such as motor oil, household cleaners and paint. • The effect of this contamination is to reduce the value of individual components for recycling • While the contamination that occurs during onsite storage decreases the value of the individual waste components, one can also argue that this contamination is beneficial with respect to the disposal of these wastes in a landfill. The concentration of the individual contaminations are reduced considerably when the contaminated waste components are spread out and compacted for land filling.

24. Storage of Solid Waste at the Source • Types of Containers • To a large extent, the types and capacities of the containers used depend on the • characteristics and types of wastes to be collected, • the types of collection system in use, • the collection frequency, and • the space available for the placement of containers • Data on the types and sizes of containers used for onsite storage of solid wastes is summarized in Table 7-4 • Typical applications and limitation of containers used for the onsite storage of solid wastes are summarized in Table 7-5.

25. Storage of Solid Waste at the Source

26. Storage of Solid Waste at the Source

27. Storage of Solid Waste at the Source • Low – Rise Dwellings with Manual Curbside Waste Collection Service • Because solid wastes are collected manually at curbside for most low –rise detached residential dwellings, the containers should be light enough to be handled easily by one collector when they are full. • The 30-gal galvanized metal or plastic container has proved to be least expensive means of storage for low-rise dwellings Galvanized Metals Noisy when emptied and can be damaged Plastic Containers Tend to crack due UV rays and Freezing temperature

28. Storage of Solid Waste at the Source • Low – Rise Dwellings with Manual Curbside Waste Collection Service • With the widespread availability of paper and plastic products, the use of container liner is now common. A disadvantage in the use of liners is that if the waste are to be separated by component, or if they are to be combusted, it is necessary to break up the liners bags in a preprocessing step. • The use of liners may be a convenience for the homeowner, liners may not be ideal from the standpoint of material recovery and recycling.

29. Storage of Solid Waste at the Source • Low – Rise Dwellings with Mechanized Curbside Waste Collection Service • Mechanical collection systems for residential services is increasing as labor and insurance premium costs rise. The containers used for the onsite storage of waste is an integral part of the collection system. • Low and Medium Rise Apartments • The two most common types are individual plastic or galvanized metal containers and large portable or fixed containers.

30. Storage of Solid Waste at the Source

31. Storage of Solid Waste at the Source • High – Rise Apartments • The most common means of storage for wastes accumulated from the individual apartments include • enclosed storage containers or disposable bags used in conjunction with compaction equipment • Large open top containers for un compacted wastes, bulky items and white goods • Large open top containers for recycled materials • Commercial Facilities • The types of containers depend on • Method used for collecting the waste produced • The available space

32. Storage of Solid Waste at the Source

33. Storage of Solid Waste at the Source • Container Storage Locations • Container storage locations depend on the type of dwelling or commercial and industrial facilities and the available space and access to the collection services • Residential Dwellings • Low rise dwellings • at the sides or rear of the house • In alleys • In or next to the garage • Low – and medium rise apartment buildings • In the basement of the buildings • Outdoor storage • High rise apartment • In the basement of the buildings

34. Storage of Solid Waste at the Source • Container Storage Locations • Commercial and Industrial facilities • The sitting of containers at existing commercial and industrial facilities depends on both the location of available space and service access conditions. • Public Health and Aesthetic • Public heath concerns are related primarily to the infestation of areas used for the storage of solid waste with vermin and insects that often serve as potential disease vectors. • Proper sanitation involves • the use of containers with tight lids • the periodic washing of containers and storage area • the periodic removal of biodegradable materials

35. Processing of Solid Waste At Residential Dwellings • Waste processing is used to • reduce the volume • recover reusable materials • alter the physical form of the solid waste • Typical onsite processing operations and facilities are listed by source in Table 7-6

36. Processing of Solid Waste At Residential Dwellings

37. Processing of Solid Waste At Residential Dwellings • Grinding of Food Waste • Because the organic material added to the wastewater has resulted in overloading many treatment facilities, it has been necessary in some communities to forbid the installation of waste food grinders in new developments until additional treatment capacity become available • Separation of wastes • one of the most effective ways to achieve the recovery and reuse of materials. Where the remaining wastes are to be combusted, the question that must be answered is, what is the energy content of residual solid waste • See example 7-3

38. Processing of Solid Waste At Residential Dwellings

39. Processing of Solid Waste At Residential Dwellings • Compaction • the two principal types of compactor used for the processing of wastes at residential dwellings are • Small (individual) home and apartment compaction units • Large compactors used to compact waste from a large number of apartments • The effect of the use of home compactor on the volume of wastes collected is illustrated in example 7-4 • the use of home compactors may also be counterproductive from stand point of subsequent processing operations • For example, if the wastes are to be separated mechanically into components at MRF, the compacted wastes will have to be broken up again before sorting. Also, by compacting, the wastes may become so saturated with the liquids present in the food wastes that the recovery of paper or other components may not be feasible because product specification may not be met

40. Processing of Solid Waste At Residential Dwellings

41. Processing of Solid Waste At Residential Dwellings • Compactors for large Apartment Buildings • Typically, a compactor is installed at the bottom of the solid waste chutes ( See fig 7-13) • Wastes falling through the chutes activate the compactor by means of photoelectric cells or limit switches. Once these switches are activated, the wastes are compressed. Depending on the design of the compactor, the compressed wastes may be formed in bales or extruded and loaded automatically into metal containers or paper bags. • where solid waste incinerators are used, the compacted wastes must be broken up to avoid delayed combustion in the furnace and high losses of unburned combustible materials. All these factors must be considered when the use of onsite compactors is being evaluated.

42. Processing of Solid Waste At Residential Dwellings • Composting • it is an effective way of reducing the volume and altering the physical composition of solid wastes while at the same time producing a useful by-product • Combustion • the choice between the two types of combustors used for high –rise apartment depends on the method of charging flue-fed and chute – fed. • in the flue –fed type, waste are charged through doors on each floor directly into refractory flue, the bottom of which opens directly into the top of the furnace combustion chamber. • In the chute – fed type, wastes are charged through hopper doors on each floor into a metal chute and they collect in a basement hopper. The wastes are then either manually or mechanically transferred into the furnace

43. Processing of Solid Waste At Commercial and Industrial Facilities • Onsite processing operations carried out at commercial – industrial facilities are generally similar to those described for residential sources. However, compaction is very important in commercial facilities. • Compaction, Shredding and Hydropulping are commonly used as means of processing of solid wastes at commercial and industrial facilities