INSPECT HUMAN WASTE DISPOSAL SYSTEMS

INSPECT HUMAN WASTE DISPOSAL SYSTEMS
EO TP1a.-d. INSPECT HUMAN WASTE DISPOSAL SYSTEMS

REFERENCES Environmental Engineering 5th Edition, pgs

SOLID WASTE MANAGEMENT
INTRODUCTION a complex process involving many technologies Generation and source reduction On-site handling and disposal Collection Transfer and transportation Processing Disposal of solid wastes The proper management of solid waste is an ongoing concern for all levels of government and directly impacts the quality of life enjoyed by citizens. Failure in any aspect of solid waste management can lead to odours, an increase in troublesome insects, rats and other foraging animals, and fires. The strike by city workers in Toronto last summer resulted in mountains of garbage and problems involving the aforementioned consequences of non-management of solid waste. Solid waste management is a complex process involving many technologies and disciplines. Associated technologies include: Generation and source reduction On-site handling and disposal Collection Transfer and transportation Processing Disposal of solid wastes

SOLID WASTE MANAGEMENT
Disciplines essential include: Administrative Financial Legal Architectural Planning Environmental Engineering functions Disciplines that are essential to integrated solid waste management include: Administrative Financial Legal Architectural Planning Environmental Engineering functions

IWM INTEGRATED WASTE MANAGEMENT (IWM)
The selection and application of suitable techniques, technologies, and management programs to achieve specific waste management objectives and goals Subject to all provincial and federal laws INTEGRATED WASTE MANAGEMENT The selection and application of suitable techniques, technologies, and management programs to achieve specific waste management objectives and goals Subject to all provincial and federal laws

IWM SOURCE REDUCTION Focuses on reducing the volume and/or toxicity of generated waste Reusable products and packaging Mulching of grass clippings SOURCE REDUCTION Focuses on reducing the volume and/or toxicity of generated waste Reusable products and packaging Mulching of grass clippings

IWM RECYLCING AND COMPOSTING
Most positively perceived and achievable of all waste management practices Returns raw materials to market by separating reusable products from the rest of the municipal waste stream Saves resources, reduces environmental impact, reduces energy consumption, improves efficiency of incinerators RECYLCING AND COMPOSTING Most positively perceived and achievable of all waste management practices Returns raw materials to market by separating reusable products from the rest of the municipal waste stream Saves resources, reduces environmental impact, reduces energy consumption, improves efficiency of incinerators by removing non-combustible materials such as metals and glass

IWM COMBUSTION (WASTE-TO-ENERGY)
Incineration attractive because it dramatically reduces the volume of waste Recovers useful energy in the form of steam or electricity Smaller physical footprint than full landfill Constraints include high cost $ and public perception of emission toxicity and safety COMBUSTION (WASTE-TO-ENERGY) Incineration attractive because it dramatically reduces the volume of waste Recovers useful energy in the form of steam or electricity Smaller physical footprint than full landfill Constraints include high cost $ and public perception of emission toxicity and safety

INCINERATION INCINERATION

IWM LANDFILLS No combination of waste management techniques that do not require landfills to make them work Technology and operation can assure protection of human health and environment Requires proper design and monitoring once closed Landfills are the one form of waste management that no one wants but everyone needs. There are no combination of waste management techniques that do not require landfills to make them work. Some wastes are simply not recyclable. Technology and operation can assure protection of human health and environment. The challenge is to ensure that all operating landfills are designed properly and monitored once closed. Today’s modern landfills look nothing like the landfills of old. They don’t receive hazardous waste or bulk liquids. They are also carefully engineered, sited and have sophisticated monitoring systems. Landfills can also turn into a resource as they produce recoverable methane gas.

LANDFILL SANITARY LANDFILL

IWM IMPLEMENTING IWM Typically involves the use of several technologies and all management options IMPLEMENTING IWM Implementing IWM for residential solid waste typically involves the use of several technologies and all management options

SOURCES OF SOLID WASTE Sources of solid waste generally related to land use and zoning General categories of solid waste Residential Commercial Institutional Construction and demolition Municipal services Treatment plant sites Industrial Agricultural In developing solid waste management programs, it is important to identify the sources, characteristics and quantities of solid waste. Knowing this is fundamental in determining the types of collection service, vehicles required, processing facilities and disposal methods used. Categories of solid waste (and these can vary by jurisdiction) Residential Commercial Institutional Construction and demolition Municipal services Treatment plant sites Industrial Agricultural

CHARACTERISTICS OF SOLID WASTE
COMPOSITION See Table 5-2, pg 767 Averages subject to several factors QUANTITIES See Table 5-3, pg 768 Estimates of quantity of solid wastes generated and collected (lbs/capita/day) SPECIFIC WEIGHT Volume occupied by solid waste and associated infrastructure Important characteristics of solid waste include the composition, quantities and specific weight. Composition See Table 5-2, pg 767 of Environmental Eng Averages are subject to many factors including time of year, habits, education, economic status of people, presence of industrial or commercial operations, urban or rural, etc. Quantities See Table 5-3, pg 768; shows estimates of the quantity of solid wastes generated and collected per day from various sources Specific Weight Refers to the volume occupied by solid waste + number and size or type of containers, collection vehicles, and transfer stations

COMMERCIAL & HOUSEHOLD HAZARDOUS WASTE
Contribute to “contamination” of ordinary municipal waste Exacerbate problems associated with waste disposal by landfill, incineration and composting 0.5% of total waste generated by households is estimated to be hazardous waste COMMERCIAL AND HOUSEHOLD HAZARDOUS WASTE Commercial and Household Hazardous Waste is known to contribute to the contamination of ordinary municipal waste by exacerbating the potential problems associated with waste disposal by landfill, incineration and composting 0.5% of total waste generated by households is estimated to be hazardous waste (batteries, electronics, etc)

CONSTRUCTION & DEMOLITION DEBRIS
Consists of uncontaminated solid waste resulting from the construction, renovation, repair, and demolition of structures and roads; also includes vegetation from land clearing, grubbing, utility line maintenance and seasonal and storm-related clean-up Includes masonry materials, soil, wood, plaster, drywall, plumbing fixtures, roofing materials, non-hazardous electrical components, etc. Not included is asbestos waste, electrical fixtures containing hazardous liquids, garbage, furniture, appliances, drums, fuel tanks, etc. Not included is processed construction debris CONSTRUCTION AND DEMOLITION DEBRIS Consists of uncontaminated solid waste resulting from the construction, renovation, repair, and demolition of structures and roads; also includes vegetation from land clearing, grubbing, utility line maintenance and seasonal and storm-related clean-up Includes masonry materials (bricks, concrete), soil, wood, plaster, drywall, plumbing fixtures, roofing materials, non-hazardous electrical components, etc. Not included is asbestos waste, electrical fixtures containing hazardous liquids, garbage, furniture, appliances, drums, fuel tanks, etc. Not included are processed construction debris – items which have been pulverized or shredded or made unrecognizable

SPECIAL WASTES MEDICAL WASTES
Infectious waste, regulated medical waste ANIMAL WASTES May contain pathogens causing disease WASTE OIL Contain toxic metals and additives USED TIRES Fires release hazardous chemicals including oil; provide harbourage and breeding sites for vermin and pests In every community, a number of solid waste materials are collected separately from residential and commercial solid waste. This includes medical wastes, animal wastes, waste oil, and old tires. MEDICAL WASTES – any solid waste generated in the diagnosis, treatment or immunization of humans or animals, in research, or in the production and testing of biological agents Infectious waste & regulated medical waste (specific materials described on pg 773) ANIMAL WASTES May contain pathogens causing disease (salmonellosis, leptospirosis, foot-and-mouth disease, BSE (Bovine Spongiform Encephelopathy) Creutzfeldt–Jakob disease in humans WASTE OIL Large quantities of waste motor and industrial oil find their way into the environment through spills, improper disposal, motor vehicles, etc. Used oils contain toxic metals and additives including lead and add to the pollution received by sources of drinking water, aquatic life, and terrestial organisms. USED TIRES Fires release hazardous chemicals including oil; provide harbourage and breeding sites for vermin and pests

QUESTIONS Teaching Points 1e –i (collection, transfer and transport, storage, waste reduction and materials recovery and composting) pg 775 – 820 reading assignment during class

SANITARY LANDFILL PLANNING, DESIGN & OPERATION
EO TPj.(1)-j.(6) SANITARY LANDFILL PLANNING, DESIGN & OPERATION

INTRODUCTION A sanitary landfill is a controlled method of solid waste disposal Sites chosen must be geologically, hydrologically and environmentally suitable must prevent groundwater pollution, provide gas (methane) venting or recovery, have a leachate collection and treatment system, provide gas and leachate monitoring wells, and be located above the 100-year flood level A sanitary landfill is a controlled method of solid waste disposal. Sites chosen must be geologically, hydrologically and environmentally suitable. It is not an open dump with associated problems such as smoke, odour, unsightliness, bird / rodent problems, etc A well-designed and operated landfill must prevent groundwater pollution, provide gas (methane) venting or recovery, have a leachate collection and treatment system, provide gas and leachate monitoring wells, and be located above the 100-year flood level.

PLANNING Key elements in the planning and implementation of a landfill
Meeting all legal requirements Engaging in inter-municipal cooperation Meeting long-term planning objectives Social and political factors Educating the public Financial support from government PLANNING There are a number of important issues that need to be identified prior to the implementation of a landfill. These include: Meeting all legal requirements Engaging in inter-municipal cooperation (cost savings with one large landfill vice several smaller ones) Meeting long-term planning objectives (costs, expected life span of landfill, future land use, etc) Social and political factors Educating the public Financial support from government

LANDFILL METHODS Trench Method Area or Ramp Method
Valley or Ravine Method LANDFILL METHODS Trench Method – trenches are dug and excavated ground used to build ramp above original ground; primarily used on level ground Area or Ramp Method – uses the existing natural slope of the land Valley or Ravine Method – solid waste is placed in “lifts” with a depth of 8-10 feet and then covered

LANDFILL METHODS Trench and Area Method of Sanitary Landfill Methods

LANDFILL METHODS This is a photo of a landfill in China that is using the valley method.

LANDFILL DESIGN ISSUES
LOCATION Proximity to waste will directly affect $cost ACCESSIBILITY Near major highways away from residential areas LAND AREA (VOLUME) REQUIRED Dependant on population served Should be sufficient for year period LOCATION Proximity to waste will directly affect $cost (10-15 miles considered economical hauling distance) ACCESSIBILITY Near major highways away from residential areas (bridges must accommodate large trucks) LAND AREA (VOLUME) REQUIRED Dependant on population served Should be sufficient for year period

LEACHATE GENERATION LEACHATE – liquid resulting from precipitation percolating through landfills containing water, decomposed waste, and bacteria desirable to prevent the development of leachate; however, it cannot in practice be entirely avoided Precipitation minus runoff, transpiration and evaporation will determine the amount of infiltration which, along with percolation, will determine amount of leachate LEACHATE GENERATION, CONTROL AND TREATMENT LEACHATE – liquid resulting from precipitation percolating through landfills containing water, decomposed waste, and bacteria In sanitary landfills, leachate is collected and treated to prevent contamination of water supplies. While it is desirable to prevent the development of leachate, it cannot in practice be entirely avoided Precipitation minus runoff, transpiration (absorption of water by plants) and evaporation will determine the amount of infiltration which, along with percolation, will determine amount of leachate

LEACHATE CONTROL If all infiltration is excluded and solid wastes kept dry, biodegradation by microorganisms will cease and solid waste will be preserved in initial state <14-16% moisture content = cessation of bacterial activity Optimal amount of moisture necessary for biodegradation, methane production, final stabilization and possible recycling of solid waste or reuse of the site LEACHATE CONTROL If all infiltration is excluded and solid wastes kept dry, biodegradation by microorganisms will cease and solid waste will be preserved in initial state <14-16% moisture content = cessation of bacterial activity Optimal amount of moisture necessary for biodegradation, methane production, final stabilization and possible recycling of solid waste or reuse of the site

LEACHATE CONTROL Landfill liners are designed to minimize or eliminate the infiltration of leachate into subsurface soils below the landfill in order to eliminate the potential for groundwater contamination LEACHATE CONTROL Landfill liners are designed to minimize or eliminate the infiltration of leachate into subsurface soils below the landfill in order to eliminate the potential for groundwater contamination

LEACHATE RECIRCULATION
Waste biodegradation and stabilization of organic matter can be accelerated by leachate recirculation Controlled recirculation, including nutrient addition to maintain optimum moisture and pH, can enhance anaerobic microbial activity, break down organics and convert them to methane and carbon dioxide Complete biological stabilization in 4-5 years LEACHATE RECIRCULATION Waste biodegradation and stabilization of organic matter can be accelerated by leachate recirculation Controlled recirculation, including nutrient addition to maintain optimum moisture and pH, can enhance anaerobic microbial activity, break down organics and convert them to methane Complete biological stabilization can be achieved in 4-5 years

LEACHATE TREATMENT Treatment required may be physicochemical - addition of chemicals such as lime followed by settling, or biological - addition of activated sludge determined by the composition of the fill material, leachate volume and characteristics, and water pollution control standards LEACHATE TREATMENT Treatment required may be physicochemical - addition of chemicals such as lime followed by settling, or biological - addition of activated sludge determined by the composition of the fill material, leachate volume and characteristics, and water pollution control standards

LEACHATE GENERATION Leachate generation and collection

LANDFILL GASES Gases found in landfills include: Methane
Carbon dioxide Nitrogen Oxygen Hydrogen sulphide Ammonia Hydrogen Carbon monoxide Gases found in landfills include: Methane and Carbon dioxide are the principal gases produced from the anaerobic decomposition of biodegradable organic waste components (45-60% by dry volume) Nitrogen (2-5%) Remaining gases are found in trace quantities often related to past use of the landfill: Oxygen Hydrogen sulphide Ammonia Hydrogen Carbon monoxide Gases are thought to occur in sequential phases with recoverable methane gas present in as little as six months depending on the landfill

CONTROL OF LANDFILL GASES
Methane (CH4) explosive in air at concentrations of 5 – 15% Because low levels of O2 present in landfills when CH4 concentrations reach this critical level, little danger landfill will explode Explosive CH4 mixtures can form if gas migrates off site and mixes with air Controlled by cutoff walls, barriers, or ventilation system such as gravel-filled trenches around perimeter of landfill CONTROL OF LANDFILL GASES Methane (CH4) explosive in air at concentrations of 5 – 15% Because low levels of O2 present in landfills when CH4 concentrations reach this critical level, little danger landfill will explode Explosive CH4 mixtures can form if gas migrates off site and mixes with air Controlled by cutoff walls, barriers, or ventilation system such as gravel-filled trenches around perimeter of landfill

CH4 RECOVERY AND UTILIZATION
CH4 production quite variable depending on the amount of decomposable material, moisture content, temperature and rate of decomposition CH4 extracted using plastic tube wells with perforations, well screens connected to a vacuum pump, or a series of horizontal gravel trenches connected to a pipe collection system CH4 RECOVERY AND UTILIZATION CH4 production quite variable depending on the amount of decomposable material, moisture content, temperature and rate of decomposition CH4 extracted using plastic tube wells with perforations, well screens connected to a vacuum pump, or a series of horizontal gravel trenches connected to a pipe collection system Fig 5-33,34,35 shows this pg 840 & 842

LANDFILL GAS COLLECTION
LANDFILL GAS COLLECTION - ONTARIO

SURFACE WATER MANAGEMENT
Runoff from drainage areas to the landfill site must ensure that surface water drainage systems such as ditches, dikes, berms, and culverts are properly designed and flows diverted from the site to prevent flooding, erosion, infiltration, and surface/ground water pollution Examine topography and soil cover for obstructions – floods, erode cover material SURFACE WATER MANAGEMENT Runoff from drainage areas to the landfill site must ensure that surface water drainage systems such as ditches, dikes, berms, and culverts are properly designed and flows diverted from the site to prevent flooding, erosion, infiltration, and surface/ground water pollution Topography and soil cover should be examined carefully to ensure there no obstructions of natural drainage channels. Obstructions can lead to floods, excessive infiltration, and erode cover material

COVER MATERIAL Final cover of a completed landfill should be soil that is easily worked yet minimizes infiltration Four feet of cover recommended if area to be landscaped, less if grass to be planted Vegetation will prevent wind and water erosion and contribute to transpiration and evaporation COVER MATERIAL Final cover of a completed landfill should be soil that is easily worked yet minimizes infiltration Four feet of cover recommended if area to be landscaped, less if grass to be planted Vegetation will prevent wind and water erosion and contribute to transpiration and evaporation

LANDFILL MINING Excavation and recycling of landfill waste may be feasible where there has been adequate moisture to permit decomposition and stabilization of the waste Factors such as landfill design, type of cover material, waste composition and age of the landfill must also be evaluated and regulatory approval granted LANDFILL MINING Excavation and recycling of landfill waste may be feasible where there has been adequate moisture to permit decomposition and stabilization of the waste Factors such as landfill design, type of cover material, waste composition and age of the landfill must also be evaluated and regulatory approval granted

LANDFILL DESIGN SANITARY LANDFILL DESIGN

QUESTIONS Reading Assignment: TP j.(7)-(9) pg 846 – 857 Landfill Facilities and Equip, Operation and Site Closure and Conversion

EO TP1k. INCINERATION

INCINERATION involves the conversion of solid wastes into gaseous, liquid, and solid conversion products with concurrent or subsequent release of energy implemented to reduce the volume of solid waste and, to the extent possible, recover energy Not recommended for small scale Landfill required for disposal of residue Incineration of solid waste involves the conversion of solid wastes into gaseous, liquid, and solid conversion products with concurrent or subsequent release of energy. It is typically implemented to reduce the volume of solid waste and, to the extent possible, recover energy. Not generally recommended for small scale (small towns, villages, apartments, schools, institutions, camps, etc) unless good design and supervision can be ensured and cost is not a concern. A landfill is required for the disposal of incinerator residue and unrecycled solid waste

MUNICIPAL SOLID WASTE INCINERATOR
Solid waste is unloaded from trucks Waste storage pit Overhead crane batch load wastes Charging chute Furnace Grates Combustion chamber 8. Boiler 9. Turbine generator 10. NO controls 11. Dry Scrubber Bag House Induced draft fan Stack Residue hopper Ash to landfill See fig 5-41 pg 858 Solid waste is unloaded from trucks into a waste storage pit. The overhead crane is used to back load wastes into the charging chute, which directs the wastes to the furnace. Solid wastes from the charging chute fall onto the grates where they are mass fired. Air may be introduced from the bottom of the grates and various gases are driven off in the combustion process. These gases and small organic particles rise into the combustion chamber and burn at temperatures greater than 1600F. Heat is recovered from the hot gases in the form of water-filled tubes that produce steam in a boiler, which is converted to electricity by a turbine generator. Air pollution control equipment may include ammonia injection for nitrogen oxides and a dry scrubber for sulfur and acid gas control and a bag house for particulate removal. To ensure adequate airflow, an induced draft fan may be needed. The end products are hot combustion gases and ash and these are discharged to the stack. Ashes and unburned materials from the grates fall into a residue hopper where they are quenched with water. Fly ash from the dry scrubber and the bag house is mixed with the furnace ash and hauled to a landfill. Fly ash – Non-combustible fine particles of solid matter expelled with flue gas from a burning process.

COMBUSTION PRODUCTS / RESIDUES
COMBUSTION ESSENTIALS: Time, temperature and turbulence (including sufficient O2) GASEOUS COMBUSTION PRODUCTS: CO2, H2O, O2, N2, SO2 COMBUSTION RESIDUES: Bottom ash, fly ash, and non-combusted organic and inorganic materials MSW burned in incinerators results in the production of combustion gases, particulates, and bottom and fly ash. COMBUSTION ESSENTIALS: Time, temperature and turbulence (including sufficient O2) GASEOUS COMBUSTION PRODUCTS: Under ideal condition, the gaseous products derived from the combustion of municipal solid waste would include CO2, H2O, O2, N2, and SO2 COMBUSTION RESIDUES: Principal solid residues are bottom ash, fly ash, and non-combusted organic and inorganic materials Residue after burning is about 25% of the original weight by volume of the solid waste

TYPES OF INCINERATORS Mass-fired Combustor
Minimal processing prior to combustion Refuse-derived Fuel-fired Combustors Produced from organic fraction of MSW Modular Combustion Units For capacities of <700 lb/hr or 250 tons/day On-site Commercial / Industrial Incinerators Hospitals, schools, industry TYPES OF INCINERATORS Mass-fired Combustor Minimal processing prior to combustion; therfore must be able to handled non-combustible materials Refuse-derived Fuel-fired Combustors Produced from organic fraction of MSW Modular Combustion Units For capacities of <700 lb/hr or 250 tons/day On-site Commercial / Industrial Incinerators Hospitals, schools, industry; continued use severely limited by air pollution control requirements

CAPACITY AND STACK HEIGHTS
Incinerators are rated in terms of tons of burnable waste per day Incinerator with capacity of 600 tons/day can theoretically handles that much solid waste in a 24-hour period or burn 400 tons in 16 hours Stacks or chimneys 150 – 200 ft above ground are constructed to provide natural draft and air supply for combustion Incinerators are rated in terms of tons of burnable waste per day. Ie. Incinerator with capacity of 600 tons/day can theoretically handles that much solid waste in a 24-hour period or burn 400 tons in 16 hours. Stacks or chimneys 150 – 200 ft above ground are constructed to provide natural draft and air supply for combustion.

CAPACITY AND STACK HEIGHTS
Heights of 300 – 600 ft are not uncommon. Discharging gases at these heights also facilitates dilution and gas dispersal Considerations in stack height include prevailing meteorological conditions, topography, adjacent land use, and air pollution standards Heights of 300 – 600 ft are not uncommon. Discharging gases at these heights also facilitates dilution and gas dispersal. Considerations in stack height include prevailing meteorological conditions, topography, adjacent land use, and air pollution standards.

INCINERATOR STACKS Does anyone recognize these incinerators and their signature stacks? Top Left - The Des Carrières Incinerator in Montreal was built in the 1970s but has been standing empty and unused since 1993. Bottom Left – Incinerator on Alcatraz Island Right – Incinerator at Spittelau Vienna; It generates enough electricity to heat 190,000 homes and 4,200 public buildings, including Vienna's largest hospital.

OPERATION A properly designed and operated incinerator requires control instrumentation for: Temperature Draft pressures Smoke emission Weights of solid wastes entering/leaving the plant Air pollution control equipment The poor image that incineration has in the eyes of many people is due largely to the failure to control the operation, with resultant destruction of equipment and air pollution. A properly designed and operated incinerator requires control instrumentation for: Temperature Draft pressures Smoke emission Weights of solid wastes entering/leaving the plant Air pollution control equipment Competent operators are also a necessity. Pg details these points.

RESIDUE MANAGEMENT Incinerator ash and fly ash leaving the furnace may contain various concentrations of hazardous materials Dioxin, cadmium and lead in ash are the contaminants of major concern ash can be solidified by cementing, vitrification, or asphalting Recycling preferred option Ash must be disposed of in a properly constructed landfill Incinerator ash and fly ash leaving the furnace may contain various concentrations of hazardous materials. These may require treatment and disposal in a manner that doesn’t endanger public health or the environment. Dioxin, cadmium and lead in ash are the contaminants of major concern and the prevention of these becoming a constituent in leachate. To minimize this, ash can be solidified by cementing, vitrification (change into a glassy substance) or asphalting. However, recycling the ash as an additive for cement (as an example) is the preferred solution. If not reused, ash must be disposed of in a properly constructed landfill. Pg details factors involved in site selection, plant layout and building design.

PUBLIC HEALTH ISSUES Emissions from modern, properly designed and operated incinerators are considered to be of minimal health significance. However, they are “perceived” to be a serious health hazard. Evidence is inconclusive as incinerator emissions are widely dispersed and their effects difficult to evaluate. Pollution controls to prevent accidental emissions must be ensured Health effects from exposure to contaminants such as dioxin, cadmium and lead are well documented Further study required Emissions from modern, properly designed and operated incinerators are considered to be of minimal health significance. However, they are “perceived” to be a serious health hazard. Evidence is inconclusive as incinerator emissions are widely dispersed and their effects difficult to evaluate. Pollution controls to prevent accidental emissions must be ensured Health effects from exposure to contaminants such as dioxin, cadmium and lead are well documented; however, further studies are required to better identify and measure the effects of air pollutants inhaled and the effects of fallout If time allows, have students search online for other public health issues regarding incinerators.

PUBLIC HEALTH ISSUES Incinerators are controversial. Wherever they are proposed as an alternative or adjunct to the issue of solid waste management, there is inevitably opposition. Justifiable? NIMBY ism? Discuss.

QUESTIONS

INSPECT HUMAN WASTE DISPOSAL SYSTEMS

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