a presentation on waste management and how we utilise the communities can deal with waste
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Language: en
Added: May 13, 2015
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Waste Management OBJECTIVES OF THE COURSE Identify the industrial and domestic sources of waste and their characteristics; Develop knowledge of waste treatment disposal and remediation processes; Understand the concepts of risk assessment and remediation standards; Describe and share practical knowledge and technology of chemical ,physical and biological treatment of hazardous waste.
Waste Management OBJECTIVES OF THE COURSE Describe and be able to apply the current remediation processes and technologies; Understand the criteria behind selection of treatment technologies and site remediation; and Educate communities and stakeholders on best practices in waste management.
Waste Management Waste Types and Sources Definition of Wastes “substances or objects which are disposed of or are intended to be disposed of or are required to be disposed of by the provisions of the law” Disposal means “any operation which may lead to resource recovery, recycling, reclamation, direct re-use or alternative uses.
Waste Management Solid wastes: domestic, commercial, mining and industrial wastes especially common as co-disposal of wastes Examples: plastics, styrofoam containers, bottles, cans, papers, scrap iron, and other trash Liquid Wastes: wastes in liquid form Examples: domestic washings, chemicals, oils, waste water from ponds, manufacturing industries and other sources
Waste Management Classification of Wastes according to their Properties. Bio-degradable can be degraded (paper, wood, fruits and others) Non-biodegradable cannot be degraded (plastics, bottles, old machines, cans, styrofoam containers and others)
Waste Management Classification of Wastes according to their Effects on Human Health and the Environment Hazardous wastes Substances unsafe to use commercially, industrially, agriculturally, or economically. Non-hazardous Substances safe to use commercially, industrially, agriculturally, or economically.
TYPES OF WASTES residential industrial commercial agricultural mining construction Municipal solid waste Hazardous waste
Waste Management PROBLEM S CAUSED BY IMPROPER DISPOSAL OF WASTE Threat to public health rodents, insects = vectors of diseases (transmit pathogens, t yphoid, plague poisonous materials flammable materials Irreversible environmental damage in ecosystems terrestrial and aquatic air pollution (incineration) water pollution (land burial) Technical and environmental difficulties +administrative, economic and social problems
Waste Management PROBLEMS WITH LAND DISPOSAL OF WASTE too little space for disposal costs harm to the environmen t and public health landfills are unreliable in long run
Waste Management Refuse (municipal solid waste) All non - hazardous solid waste from a community Requires collection and transport to a processing or disposal site Ordinary refuse : g arbage + rubbish Garbage Highly decomposable food waste Vegetable + meat Rubbish G lass, rubber, tin cans S lowly decomposable or combustible material – paper, textile, wood Trash Bulky waste material that requires special handling Mattress, TV, refrigerator Collected separately
COMPOSITION OF URBAN SOLID WASTE 0,6 – 1,2 m 3 waste / day / person 120 – 250 kg / m 3 without compaction 40-50% is paper
Waste Management Responsibility of the local municipality refuse collection vehicles enclosed, compacting type with a capacity of 15 m 3 compaction: 50% reduction Frequency of collection and the point of pickup depends: type of community population density land use in the collection area combined collection of garbage and rubbish is cheaper for recycling it is essential to separate separated collection!!! (paper, metal, plastic, glass, organics, chemicals, batteries)
Waste Management WASTE TREATMENT AND RESOURCE RECOVERY Reduce the total volume and weight of material that requires disposal Help to conserve land resources Change the form or characteristic of waste Composting, neutralizing , shredding, incineration Recover natural resources and energy in the waste material Recycling and reuse!!! (it takes 17 trees to make 1 ton of paper)
Waste Disposal Methods 14
Predominant method of waste disposal in developing countries Illegal dumping problems Groundwater contamination , air pollution, pest and health hazards 15 Open Dumps
What is a solid waste Any material that we discard, that is not liquid or gas, is solid waste Municipal Solid Waste (MSW): Solid waste from home or office Industrial Solid Waste: Solid waste produced from Mines, Agriculture or Industry
Municipal Solid Waste (MSW)
Waste Management
Benefits of Recycling The ultimate benefits from recycling are cleaner land, air, and water, overall better health, and a more sustainable economy.
Municipal Waste On-site (at home) Open Dump Sanitary Landfill Incineration Ocean dumping
Open Dump Unsanitary, draws pests and vermin, harmful runoff and leachates, toxic gases Still accounts for half of solid waste
Sanitary Landfill Sanitary Landfill Layer of compacted trash covered with a layer of earth once a day and a thicker layer when the site is full Require impermeable barriers to stop escape of leachates: can cause problem by overflow Gases produced by decomposing garbage needs venting
Sanitary Landfill Leachates is any liquid that in passing through matter, extracts solutes, suspended solids or any other component of the material through which it has passed. In the narrow environmental context leachate is therefore any liquid material that drains from land or stockpiled material and contains significantly elevated concentrations of undesirable material derived from the material that it has passed through
Sanitary Landfill Avoid: Swampy area/ Flood plains /coastal areas Fractures or porous rocks High water table Prefer: Clay layers Heads of gullies
Monitoring of Sanitary Landfills Gases: Methane, Ammonia, Hydrogen sulphide Heavy Metals: Lead, Chromium in soil Soluble substances: chloride, nitrate, sulfate Surface Run-offs Vegetation: may pick up toxic substances Plant residue in soil Paper/plastics etc – blown by the wind
Incineration Solves space problem but: produces toxic gases like Cl , HCl , HCN, SO 2 High temp furnaces break down hazardous compounds but are expensive ($75 - $2000/ton) Heat generated can be recovered: % of waste burnt
Ocean Dumping Out of sight, free of emission control norms Contributes to ocean pollution Can wash back on beaches, and can cause death of marine mammals Preferred method: incineration in open sea Ocean Dumping Ban Act, 1988: bans dumping of sewage sludge and industrial waste Dredge spoils still dumped in oceans, can cause habitat destruction and export of fluvial pollutants
Ways of Reducing Solid Waste Incineration, compacting Hog feed: requires heat treatment Composting: requires separation of organics from glass and metals Recycling and Reusing
Recycling: facts and figures In 1999, recycling and composting activities prevented about 64 million tons of material from ending up in landfills and incinerators. Today, this country recycles 32 percent of its waste, a rate that has almost doubled during the past 15 years. 50 percent of all paper, 34 percent of all plastic soft drink bottles, 45 percent of all aluminum beer and soft drink cans, 63 percent of all steel packaging, and 67 percent of all major appliances are now recycled. Twenty years ago, only one curbside recycling program existed in the United States, which collected several materials at the curb. By 2005, almost 9,000 curbside programs had sprouted up across the nation. As of 2005, about 500 materials recovery facilities had been established to process the collected materials.
Waste Exchange One persons waste can be another persons raw material Isopropyl alcohol = cleaning solvent Nitric Acid from Electronic Industry = high grade fertilizer Spent acid of steel industry = control for H 2 S
LANDFILL DESIGN Modern landfills are designed to minimise these problems: Location Landfill Liner Compaction of waste Daily Cover Landfill Cap Leachate Management System Landfill Gas management System
LANDFILL LOCATION In order to obtain a permit a landfill operator must first carry out a detailed investigation and prove to the satisfaction of the planning authority and the EA that the site: is located in a geologically stable area is not located on a major aquifer; Is not located in a vulnerable area; is designed to reduce the risk of damage to the environment and human health; will be monitored regularly for the duration of operations and aftercare period.
Installation of monitoring/site investigation borehole
LANDFILL LINERS Landfill Liners are constructed on the base and sides of a landfill site to prevent leachate from leaking into the surrounding soils. Landfill Liners may be constructed from: Compacted Clay Bentonite Enhanced Sand Geomembrane Geotextile Protector Dense Asphaltic Concrete (DAC) Combination of the above
LANDFILL LINERS Construction of compacted clay liner
LANDFILL LINERS
LANDFILL LINERS Installation of Geomembrane Basal Liner
LANDFILL LINERS Construction of Dense Asphaltic Concrete Liner This is a new method of lining landfills. The first landfill to be constructed with this type of lining system in the UK is North of London and was completed this summer.
LANDFILL LINERS
CONSTRUCTION QUALITY ASSURANCE All construction carried out on landfill sites is supervised and recorded by an independent consultant. Following construction, certification reports are produced by the consultant and issued to the Environment Agency for approval.
LANDFILL OPERATIONS Waste is placed in layers approximately 3 m thick and compacted. At the end of each working day approximately 0.3 m of clay or sand material is placed on top of the waste to: minimise the infiltration of rainwater isolate the waste from birds and vermin reduce odours
LANDFILL OPERATIONS To prevent wastage and the formation of layers of weakness within the waste mass the daily cover is scraped off and re-used each day. Leachate that collects at the base of the waste mass is collected and re-circulated into the waste. This: increases the rate of decomposition of the waste and therefore, rate of settlement; decreases disposal costs.
LANDFILL CAP Landfill caps placed above the waste after completion of infilling prevent the infiltration of rainwater, minimising the production of leachate. Landfill Caps are usually constructed from: Recompacted clay Geomembrane
LANDFILL CAP Construction of geomembrane cap
LANDFILL CAP
LEACHATE MANAGEMENT SYSTEM Leachate management systems are installed to: prevent the accumulation of leachate in the base of the landfill collect, re-circulate and dispose of leachate during operations and after closure They comprise of: leachate drainage blanket at base of landfill pipes along base and sidewalls of landfill wells to monitor and extract the leachate
LANDFILL GAS MANAGEMENT SYSTEM Landfill gas management systems are installed to prevent the build up of gases within the landfill and to prevent migration of landfill gas through the underlying strata. There are 2 ways landfill gas can be managed: passive active
LANDFILL GAS MANAGEMENT SYSTEM Passive management systems comprise of wells with perforated tops to allow the gas to vent into the atmosphere Active management systems involve the active extraction of the gas. The extracted gas can be used to generate electricity.
LANDFILL GAS MANAGEMENT SYSTEM Electricity generating system
MONITORING Monitoring is carried out before, during, and after the placement of waste. Numerous monitoring wells are constructed around a landfill site (both upstream and downstream) to check for contamination. Chemical testing is carried out regularly on: Groundwater Leachate Landfill Gas
37/64 4- Landfills Public/private ownership and operation In most developing countries landfills are owned and operated by local governments. Where expertise is available in the private sector, municipal planners should explore the option of privatizing landfill operations on a contractual basis. This option should be weighed carefully in bases of cost recovery and the payment of fees.
38/64 4- Landfills Monitoring and control of leachate: Leachate management is a key factor in safe landfill design and operation. The natural decomposition of MSW and rain infiltration into the site causes potentially toxic contaminants. The wetter the climate is the greater potential risks of ground- and surface water contamination. The geology of a site can exacerbate or reduce amount of leachate.
39/64 4- Landfills Continue Monitoring and control of leachate: Household hazardous waste (e.g., paint products, garden pesticides, automotive products, batteries) and hazardous wastes from commercial and industrial generators can release organic chemical and heavy metals contaminants in leachate.
40/64 4- Landfills Continue Monitoring and control of leachate: Natural or synthetic materials are used to line the bottom and sides of landfills to protect ground and surface water. Two feet or more of compacted clay, thin sheets of plastic made from a variety of synthetic materials and others used in lining landfills. Natural and synthetic liners can crack, if improperly installed, or can lose strength over time.
41/64 4- Landfills Continue Monitoring and control of leachate: More than one liner or a mix of natural and synthetic liners, called a composite liner, is a recommended alternative. To minimize production of leachate, covering material should be applied after each day of MSW is spread.
42/64 4- Landfills
43/64 4- Landfills Leachate collection and treatment: Leachate collection systems are installed above the liner and consist of a perforated piping system which collects and carries the leachate to a storage tank. Periodically, leachate removed from the storage tank and treated or disposed of. Most common leachate management methods are: discharge to wastewater treatment plant, on-site treatment and recirculation back into the landfill.
44/64 4- Landfills Leachate recirculation over waste in landfills showed an increase the quantity (by factor of 10) and quality of methane gas for recovery as well as possibly reduces the concentration of contaminants in leachate and enhances the settling of the waste.
45/64 4- Landfills Leachate reinjection may be appropriate for areas with low rainfall. This technology could be more cost-effective than other treatment systems.
46/64 4- Landfills P ossible drawbacks of leachate recirculation include clogging of leachate collection systems, increasing release of leachate to the environment and increasing odor problems.
47/64 4- Landfills At controlled dumps monitoring operations may involve the scheduled withdrawal of samples to test for indicator contaminants such as bacteria, heavy metal ions, and toxic organic acids.
48/64 4- Landfills Monitoring operations at sanitary landfills may involve computerized statistical sampling and automatic reporting of results at the regulatory agency. Such systems are costly and require skilled personnel.
49/64 4- Landfills Monitoring and control of landfill gas Gas management is required at sanitary landfills. At controlled dumps, it should be monitoring to determine if dangerous amounts of gas are being released. A low-cost design (passive collection system) to handle landfill gas consists of covered vertical perforated pipes, using natural pressure of gas to collect and vent or flare it at surface. More costly active collection systems utilize covered network of pipes and pumping to trap it. Gas is processed and used for process heat or electricity. This collection system is risky and expensive.
50/64 4- Landfills Continue Monitoring and control of landfill gas Gas management is required at sanitary landfills. At controlled dumps, it should be monitoring to determine if dangerous amounts of gas are being released. A low-cost design (passive collection system) to handle landfill gas consists of covered vertical perforated pipes, using natural pressure of gas to collect and vent or flare it at surface. More costly active collection systems utilize covered network of pipes and pumping to trap it. Gas is processed and used for process heat or electricity. This collection system is risky and expensive.
57/64 4- Landfills Access and tipping area Fencing should be designed to restrict unauthorized access to the landfill and to keep out animals. A staffed gate should be the point of entry to the facility for vehicles and any waste pickers. Gate should be equipped with scales for the weighing of vehicles as they enter and exit the facility. They provide critical information for planning purposes and for operational management of collection vehicles.
59/64 4- Landfills Pre-processing and waste picker policy Landfill is the least efficient alternative for materials recovery operations. Where composting is attractive at the landfill and/or waste picking activity is permitted, sorting of the waste should occur close to the gate or tipping area rather than at the working cell. Such activities reduce the volume of material to be landfilled and extend the life of the facility. Waste picking policy should be established during the design phase of the facility
60/64 4- Landfills Operations and safety manuals Manuals should be prepared during the design phase of the landfill. This permits their content to be specifically adapted to the processes for which the facility is designed. Clear operating procedures and well-trained workers are vital to safe and effective landfill operations.
61/64 4- Landfills Closure/post-closure plans Essential closure and post-closure elements are: Plans for the sealing and application of final cover (including vegetation) Plans for long-term leachate and gas management system monitoring;
62/64 4- Landfills Continue Closure/post-closure plans Plans for long-term ground and surface water monitoring; Financial assurance guarantees to the local or state government; and Land use restrictions for the site
63/64 4- Landfills In the case of controlled dumps in most developing countries, closure and post-closure plans are not prepared. However, ongoing monitoring and control of the facility after its useful life is an unavoidable for periods that may exceed 30 years after their closure.
64/64 4- Landfills Community relations The designer should establish a program for ongoing dialog with community. This should be based on transparency in landfill operations and procedures to addressing community concerns. Some facilities offer give-backs to their host community.
Wastewater Treatment
Liquid Waste Sewage Highly toxic Industrial Waste & Used Oil Dilute and Disperse Concentrate and Contain Secure Landfill Sealed drums to be put in impermeable holds with monitoring wells to check for leakage: does not work Deep well Disposal Pumping in deep porous layer bounded by impermeable formations, well below water table $1 million to drill, $15-20/ton afterwards Restricted by geological considerations, can trigger earthquakes
Wastewater Treatment Purpose: To manage water discharged from homes, businesses, and industries to reduce the threat of water pollution .
Wastewater Treatment Pre-treatment - Occurs in business or industry prior to discharge - Prevention of toxic chemicals or excess nutrients being discharged in wastewater
Wastewater Treatment Water discharged from homes, businesses, and industry enters sanitary sewers Water from rainwater on streets enters storm water sewers Combined sewers carry both sanitary wastes and storm water
Wastewater Treatment Water moves toward the wastewater plant primarily by gravity flow Lift stations pump water from low lying areas over hills
Wastewater Treatment
Wastewater Treatment Preliminary Treatment - removes large objects and non-degradable materials - protects pumps and equipment from damage - bar screen and grit chamber
Wastewater Treatment Bar Screen - catches large objects that have gotten into sewer system such as bricks, bottles, pieces of wood, etc.
Wastewater Treatment Measurement and sampling at the inlet structure - a flow meter continuously records the volume of water entering the treatment plant - water samples are taken for determination of suspended solids and B.O.D.
Wastewater Treatment Suspended Solids – the quantity of solid materials floating in the water column B.O.D. = Biochemical Oxygen Demand - a measure of the amount of oxygen required to aerobically decompose organic matter in the water
Wastewater Treatment Measurements of Suspended Solids and B.O.D. indicate the effectiveness of treatment processes Both Suspended Solids and B.O.D. decrease as water moves through the wastewater treatment processes
Wastewater Treatment Primary Treatment -- a physical process -- wastewater flow is slowed down and suspended solids settle to the bottom by gravity -- the material that settles is called sludge or biosolids
Wastewater Treatment Primary Treatment
Wastewater Treatment Primary Treatment
Wastewater Treatment Primary Treatment
Sludge from the primary sedimentation tanks is pumped to the sludge thickener. - more settling occurs to concentrate the sludge prior to disposal Wastewater Treatment
Wastewater Treatment Primary treatment reduces the suspended solids and the B.O.D. of the wastewater. From the primary treatment tanks water is pumped to the trickling filter for secondary treatment. Secondary treatment will further reduce the suspended solids and B.O.D. of the wastewater.
Wastewater Treatment Secondary Treatment
Wastewater Treatment Secondary Treatment Secondary treatment is a biological process Utilizes bacteria and algae to metabolize organic matter in the wastewater In Cape Girardeau secondary treatment occurs on the trickling filter
Wastewater Treatment Secondary Treatment the trickling filter does not “filter” the water water runs over a plastic media and organisms clinging to the media remove organic matter from the water
Wastewater Treatment From secondary treatment on the trickling filter water flows to the final clarifiers for further removal of sludge. The final clarifiers are another set of primary sedimentation tanks. From the final clarifiers the water is discharged back to the Mississippi River.
Wastewater Treatment The final clarifiers remove additional sludge and further reduce suspended solids and B.O.D.
Wastewater Treatment Disposal of Sludge or Biosolids -- the sludge undergoes lime stabilization (pH is raised by addition of lime) to kill potential pathogens -- the stabilized sludge is land applied by injection into agricultural fields
Wastewater Treatment Disposal of Sludge or Biosolids -- in the past, the sludge was disposed by landfill or incineration -- landfill disposal discontinued to the threat of leachate -- incineration discontinued because of the ineffectiveness and cost
Wastewater Treatment The final part of the field trip tour will be in the treatment plant lab.
Wastewater Treatment The wastewater plant lab conducts a number of measurements and tests on the water. suspended solids temperature B.O.D. nitrogen pH phosphorus
Wastewater Treatment In addition to test performed at the wastewater lab, an off-site contract lab performs additional tests heavy metals priority pollutants W.E.T (Whole Effluent Toxicity) tests
TRP Chapter 2.1 111 HAZARDOUS WASTE
TRP Chapter 2.1 112 General definition A hazardous waste has the potential to cause an unacceptable risk to: PUBLIC HEALTH THE ENVIRONMENT
TRP Chapter 2.1 113 Why definition is difficult HAZARDOUS WASTE PHYSICAL FORM PHYSICAL PROPERTIES CHEMICAL PROPERTIES COMPOSITION The hazard associated with a waste depends on: BIOLOGICAL PROPERTIES
TRP Chapter 2.1 114 Examples of hazardous waste definitions: Basel Convention 45 categories of wastes that are presumed to be hazardous. PLUS …... These categories of waste need to exhibit one or more hazardous characteristics: flammable, oxidising, poisonous, infectious, corrosive, ecotoxic
TRP Chapter 2.1 115 Examples of hazardous waste definitions: UNEP Wastes other than radioactive wastes which, by reason of their chemical activity or toxic, explosive, corrosive or other characteristics cause danger or are likely to cause danger to health or the environment
TRP Chapter 2.1 116 Examples of hazardous waste definitions UNDER United Nations REGULATIONS: 1 The waste is listed in UNEP regulations 2 The waste is tested and meets one of the four characteristics established by UNEP: Ignitable Corrosive Reactive Toxic 3 The waste is declared hazardous by the generator
TRP Chapter 2.1 117 The objective of definitions Why define wastes? To decide whether or not that waste should be controlled - this is important for the generator as well as the regulator Why create a list? Clear and simple No need for testing
TRP Chapter 2.1 118 Different methods of classification Lists eg Basel Convention Annex I, Basel List A, EU European Waste Catalogue, US EPA list Origin eg processes, Basel Convention Annex II Hazardous characteristics eg toxicity, reactivity, Basel Convention Annex III Chemical and physical properties eg inorganic, organic, oily, sludges Need to match classification to objectives No method will suit all cases
TRP Chapter 2.1 119 Methods of waste classification: by origin Waste streams eg Basel Convention Miscellaneous or ubiquitous wastes eg contaminated soils dusts redundant pesticides from agriculture hospital wastes
TRP Chapter 2.1 120 Example of waste classification by origin: Basel The Basel Convention’s List of Hazardous Waste Categories (Y1-Y18) identifies wastes from specific processes eg Y1 Clinical wastes Y6 Wastes from the production and use of organic solvents Y18 Residues from industrial waste disposal operations
TRP Chapter 2.1 121 Methods of waste classification: by hazardous characteristics Main characteristics: Toxic Corrosive UN Committee on the Transport of Dangerous Goods by Road or Rail (ADR) lists waste characteristics. These have been adopted by Basel Convention - Annex III gives 13 characteristics, based on ADR rules, including: Explosive Flammable Toxic and eco-toxic Represented as codes H1-H13 Ignitable Reactive
TRP Chapter 2.1 122 Hazardous characteristics: Toxicity Toxic wastes are harmful or fatal when ingested, inhaled or absorbed through the skin Examples: Spent cyanide solutions Waste pesticides
TRP Chapter 2.1 123 Hazardous characteristics: Corrosivity Acids or alkalis that are capable of dissolving human flesh and corroding metal such as storage tanks and drums Examples: acids from metals cleaning processes eg ferric chloride from printed circuit board manufacture liquor from steel manufacture
TRP Chapter 2.1 124 Hazardous characteristics: Ignitability Ignitable wastes: can create fires under certain conditions or are spontaneously combustible Examples: Waste oils Used solvents Organic cleaning materials Paint wastes
TRP Chapter 2.1 125 Hazardous characteristics: Reactivity Reactive wastes are unstable under ‘normal conditions’ They can cause: explosions toxic fumes gases or vapours Examples: Peroxide solutions Hypochlorite solutions or solids
TRP Chapter 2.1 126 Hazardous characteristics: Eco-toxicity Eco-toxic wastes are harmful or fatal to other species or to the ecological integrity of their habitats Examples: Heavy metals Detergents Oils Soluble salts
TRP Chapter 2.1 127 Methods of waste classification: by chemical, biological and physical properties Inorganic wastes eg acids, alkalis, heavy metals, cyanides, wastewaters from electroplating Organic wastes eg pesticides, halogenated and non-halogenated solvents, PCBs Oily wastes eg lubricating oils, hydraulic fluids, contaminted fuel oils Sludges eg from metal working, painting, wastewater treatment
TRP Chapter 2.1 128 Hazardous waste from households - outside the controls in many countries Small quantity generators - often placed outside the system, at least initially Aqueous effluents discharged to sewer or treated on-site - controlled separately from hazardous wastes in most countries Sewage sludge - excluded in some countries Mining wastes - often excluded Agricultural waste - often excluded Nuclear waste - always excluded Exclusions from control systems Some wastes may be excluded from the legal definition of hazardous wastes, and thus not subject to controls. These vary, but may include:
TRP Chapter 6.5 129 Thermal treatment
TRP Chapter 6.5 130 Definitions Thermal treatment = destruction of hazardous waste by thermal decomposition Thermal treatment methods include: incineration - complete combustion using excess oxygen gasification - incomplete combustion in the partial absence of oxygen pyrolysis - thermal decomposition in the total absence of oxygen
TRP Chapter 6.5 131 Application of thermal treatment Suitable for organic wastes Thermal treatment processes: require high capital investment are highly regulated need skilled personnel require high operating and safety standards have medium to high operating costs
TRP Chapter 6.5 132 Good practice in hazardous waste combustion 3 Ts: Time Temperature Turbulence Flue gas cleaning systems
TRP Chapter 6.5 133 Waste characteristics Different waste types have different heat values ie the amount of heat released during complete combustion - Calorific Value (CV) Gross Calorific Value (CV) includes heat released by steam condensation Net Calorific Value does not include the heat from condensation Also important: Flash point Viscosity Chlorine, fluorine, sulphur & heavy metals
TRP Chapter 6.5 134 Examples of Calorific Value Mixed waste from plant cleaning operations 10,000 - 30,000 kj/kg Wastewater 5,000 kj/kg (0 - 10,000kj/kg depending on organic content) Industrial sludge 1,000 - 10,000 kj/kg Paints and varnishes >20,000 kj/kg Chlorinated hydrocarbons 5,000 - 20,000 kj/kg For comparison, MSW = ~10,000kj/kg Source: Indaver
TRP Chapter 6.5 135 Combustion Requires: addition of excess air mechanical mixing of waste even distribution and aeration of waste Behaviour of waste during combustion varies according to its heat value and its form Some low CV wastes burn easily = straw Some low CV wastes are difficult to burn = wet sludges Some high CV wastes burn easily = tank bottoms Some high CV wastes are difficult to burn = contaminated soils, certain plastics Certain wastes change their physical characteristics during combustion
TRP Chapter 6.5 136 Combustion techniques Bed plate furnaces : use gravity to mix waste - used for homogeneous and wet wastes such as sludge cake Fluidised bed furnaces : waste is introduced into a bed of sand which is kept in suspension - used for wastes of similar size and density Incineration grates : wastes fed onto the grate are turned or moved to ensure aeration of the waste mass via holes in the grate - used for solid wastes eg municipal wastes, not liquids or sludges Rotary kilns : wastes are placed in slowly rotating furnace - suitable for solids, sludges and liquids
TRP Chapter 6.5 137 Operation of the furnace good understanding of waste characteristics technical skills control of waste feed mixing of wastes temperature to be kept at required level despite variations in waste excess air flue gas control regular maintenance Must be consistent Needs: Source: David C Wilson
TRP Chapter 6.5 138 Energy recovery Waste combustion produces heat but combustion of low CV wastes may not be self-supporting Energy recovery is via production of steam to generate electricity Only steam production: 80% efficiency is typical Steam can be used for in-house demands Steam can be delivered to adjacent users eg other industrial plants Electricity can be generated: 25% efficiency typical Opportunities to sell heat are improved where facilities are in industrial areas Sale of surplus energy improves plant economics
TRP Chapter 6.5 139 By-products of incineration May be: solid liquid gaseous Comprise: recovered materials such as metals, HCl flue gases slag and ash products of the flue gas treatment, also called air pollution control (APC) residues wastewater
TRP Chapter 6.5 140 Solid residues bottom ash or slag fly ash air pollution control (APC) residues Terms and regulations on treatment and disposal of solid residues differ between countries Bottom ash may be landfilled or used as an aggregate substitute eg for road building
TRP Chapter 6.5 141 Flue gases Quantity and type of pollutants in emissions depend on: pollutants in waste technology efficiency of operation Average 6 - 7 Nm 3 of flue gas per kg waste Specific collection/treatment for: Dust - staged filters Chlorine - neutralised by scrubbing with lime Sulphur - washing stage Dioxins - combustion control, activated carbon Source: David C Wilson
TRP Chapter 6.5 142 Dioxins Family of around 200 chlorinated organic compounds, a few of which are highly toxic Widespread in the environment Present in waste going to incineration Can be re-formed in cooling stages post-combustion 3Ts help destroy dioxins in waste, reduce reformation Use of activated carbon to filter from flue gases Emissions limits extremely low
TRP Chapter 6.5 143 Example of flue gas cleaning technology Source: Indaver
TRP Chapter 6.5 144 Wastewater from incineration Controls vary from country to country Quantity: influenced by gas scrubbing technology chosen ie wet, semi-dry, dry Treatment: in aerated lagoons widely used low cost may not meet required standard physico-chemical treatment may also be needed
TRP Chapter 6.5 145 Measurement Of what: controlled parameters eg carbon monoxide How: regular continuous Set out in: national regulations permitted operating conditions Problems: · Measuring equipment may be imprecise · Errors in correlation · Errors in sampling
TRP Chapter 6.5 146 Measurement: an example Emissions from rotary kiln incinerator Continuous monitoring for: HCl, CO, dust, SO2, HF, TOC, Nox, O2 Monthly measurement for: 9 heavy metals Twice a year (soon to be continuous): PCDD/PCDF ALSO monitored: wastewater and solid residues Source: Indaver, Belgium
TRP Chapter 6.5 147 Costs Related to site-specific and country-specific factors High level of sophistication & control = high construction costs Air pollution control costs = 30-40% of total Treatment costs per tonne similar to other technologies Cost savings because volume, weight and hazard of waste remaining for disposal greatly reduced Recovery and sale of energy/heat from the process improves economics
TRP Chapter 6.5 148 Cement kiln incineration Widely used for range of hazardous wastes eg oily wastes, wastewaters, sludges, solvents, organic compounds Provides: good combustion conditions alkaline environment vacuum operation high thermal inertia no impact on quality of cement product opportunity to recover energy content of waste no by products
TRP Chapter 6.5 149 Requirements for co-combustion in cement kilns suitable for pumpable organic wastes not suitable for wastes with high water, sulphur, chlorine, heavy metals content waste needs pre-treatment/blending for use as fuel adaptations may be needed eg fuel feed, dust controls must meet Health and Safety concerns re handling of hazardous wastes dependent on demand for product
TRP Chapter 6.5 150 Examples of technology 1 Rotary kiln incinerator Source: Guyer, Howard H Industrial processes and waste stream management, Wiley
TRP Chapter 6.5 151 Examples of technology 2 Fluidised bed combustion Circulating fluidised bed Bubbling fluidised bed Source: Guyer, Howard H Industrial processes and waste stream management, Wiley
TRP Chapter 6.5 152 Pyrolysis Pyrolysis = thermal decomposition process which takes place in the total absence of oxygen Products of pyrolysis: combustible gases mixed liquid residue Advantages: low operating temperature no need for excess air so less flue gas by-products are combustible
TRP Chapter 6.5 153 Application of pyrolysis For single waste streams such as: scrap tyres waste plastics For treatment of contaminated soils
TRP Chapter 6.5 154 Gasification Gasification = incomplete combustion in the partial absence of oxygen Enables efficient destruction of hazardous waste at lower temperatures than incineration Thermal destruction is ensured by a combination of high-temperature oxidation followed by high temperature reduction Products: useful gases eg hydrogen, carbon monoxide solid char
TRP Chapter 6.5 155 Key considerations Waste reduction and avoidance by generators should always be a priority Need to consider residues from treatment processes and their disposal Thermal treatment is the best available technology for some organic hazardous wastes - providing that it is designed, managed and operated properly There is often opposition from the public and from environmental groups, largely based on dioxin concerns
TRP Chapter 6.5 156 Summary Thermal treatment: is s uitable for organic wastes includes different technologies, all require high capital investment is highly regulated, requires high operating and safety standards needs skilled personnel has medium to high operating costs generates useful energy has by-products which need careful handling often attracts opposition
TRP Chapter 4.2 157 Waste minimisation
TRP Chapter 4.2 158 Why minimise waste? On-site recycling Off-site recycling disposal disposal source source waste No waste minimisation With waste minimisation, recycling and treatment to treatment waste
TRP Chapter 4.2 159 Preferred hierarchy of waste management options Source reduction On-site/off-site recycling Treatment Final disposal Waste diversion
TRP Chapter 4.2 161 Factors influencing waste minimisation Government policy and regulations Technological feasibility Economic viability Management commitment and support
TRP Chapter 4.2 162 Waste minimisation - incentives Reduced costs: raw materials, energy, water storage and handling waste disposal health and safety Regulatory compliance Improved efficiency Improved corporate image
TRP Chapter 4.2 164 Waste minimisation opportunities applicable to all operations 1 Use higher purity materials Use less toxic raw materials Use non-corrosive materials Convert from batch to continuous process Improve equipment inspection & maintenance Improve operator training Improve supervision Improve housekeeping
Waste minimisation opportunities applicable to all operations 2 Improve material tracking and inventory control: avoid over-purchasing inspect deliveries before acceptance make frequent inventory checks label all containers accurately ensure materials with limited shelf-life are used by expiry date where possible, install computer-assisted inventory control
Case studies Delivering textile dyeing wastewater, Thailand
TRP Chapter 4.2 167 Implementing a company waste minimisation programme A systematic and ongoing effort to reduce waste generation Must be tailored to specific company needs and practices 3 main phases: planning and organisation conducting a waste audit implementing, monitoring and reviewing
TRP Chapter 4.2 168 Phase 1: Planning and organisation Obtain management commitment Establish programme task force Set goals and priorities Establish an audit team
TRP Chapter 4.2 169 Phase 2: Waste audit 6 main steps: identify plant operations define process inputs define process outputs assess material balance identify opportunities conduct feasibility study
TRP Chapter 4.2 170 Step 1: Identify plant operations Inspect the site Identify different processes undertaken on site List processes and obtain as much information as possible on them
TRP Chapter 4.2 171 Step 2: Define process inputs Account for all the material flows into each individual process materials energy water Make sure all inputs are accounted for in detail eg kg of raw materials, kilowatts of electricity, litres of water Make sure figures are on same basis eg annual, monthly, weekly inputs
TRP Chapter 4.2 172 Step 3: Define process outputs Identify and quantify all process outputs primary products co-products waste for re-use or recycling waste for disposal
TRP Chapter 4.2 173 Step 4: Assess material balance To ensure that all resources are accounted for, conduct a materials balance assessment = Total material in Total material out + Product
TRP Chapter 4.2 174 Typical components of a material balance Inputs Outputs Production process or unit operation Raw material 1 Raw material 2 Raw material 3 Water/air Product By-product Wastewater Wastes for storage or off-site disposal Gaseous emissions
TRP Chapter 4.2 175 Step 5: Identify opportunities for waste minimisation Using data acquired during the waste audit, make preliminary evaluation of the potential for waste minimisation Prioritise options for implementation
TRP Chapter 4.2 176 Step 6: Conduct feasibility study Conduct feasibility analysis of selected options Technical considerations: Availability of technology Facility constraints including compatibility with existing operation Product requirements Operator safety and training Potential for health and environmental impacts Economic considerations: Capital and operating costs Pay-back period
TRP Chapter 4.2 177 Phase 3: Implementing, monitoring and reviewing Prepare Action Plan Identify resources Implement the measures Evaluate performance
TRP Chapter 4.2 178 Summary There are a number of good reasons for minimising waste - source reduction comes at the top of the waste hierarchy Factors which influence waste minimisation include regulations, technological feasibility, economic viability and management support There are both incentives and barriers; some opportunities widely applicable - and valuable experience from demonstration projects Guide to implementing a company waste minimisation programme and conducting an audit
WELCOME RECYCLING SOLID WASTE
WHAT IS RECYCLING? Recycling turns materials that would otherwise become waste into valuable resources and generates a host of environmental, financial, and social benefits. After collection, materials (e.g., glass, metal, plastics, and paper) are separated and sent to facilities that can process them into new products and materials
KEY PEOPLE Step 1. – Key People - Select a Recycling Coordinator The recycling coordinator will need to have good communication and organizational skills. Creativity, patience, persistence, a sense of humor, and good rapport with other people in your business are important character qualities If you are the owner or manager of a small business, you will probably be the coordinator, at least in the beginning
KEY PLAYERS A coordinator’s role typically includes: Conduct a waste audit and determine what to recycle Selecting the contractor Designing the collection system Educating employees Tracking the program’s progress Designate area monitors to assist the coordinator in: - Keeping the collection containers free of non-recyclable material - Notifying the coordinator if containers overflow - Encouraging employee participation
KEY PEOPLE Step 1. – Key People - Cleaners Always involve janitors in the planning process for any recycling program Additional training may be necessary to familiarize them with new or alternative waste collection procedures Realistically assess their safety concerns and how changes will affect their workload The cleaners' commitment and cooperation in executing your recycling program are crucial to success You may need to modify the janitorial contract to specify recycling services.
KEY PEOPLE Step 1. – Key People - Landscape Contractors Plant waste from decorative landscaping for many downtown courtyards, atriums, and sidewalks often goes straight to landfill By working with your landscape contractor, you can potentially have plant waste hauled to a commercial composting facility
KEY PEOPLE Step 1. – Key People – Food Handlers Food and other "wet wastes" contaminate dry recyclable waste unless you keep them in separate dumpsters It may be possible to reduce food waste through the suggestions of food handlers Donating food may be another alternative rather than disposal Food waste can also be recycled through composting
KEY PEOPLE Step 1. – Key People - Construction Contractors The materials generated during the demolition phase of a renovation are mostly recyclable It is necessary to provide the contractor with a staging area and time in which to separate the materials If the contractor separates the materials, the value of the material can be rebated back to reduce hauling costs
WASTE AUDIT Step 2. – Conduct a Waste Audit The reason to conduct a waste audit is to find out what’s in your trash The waste audit will help you identify which materials to collect for recycling, what size and type of containers you will need, and what waste could possibly be prevented in the first place Find out if your company or individual employees are already collecting any materials for recycling A waste sort or “dumpster diving” should be the first place to gather “bottom line” information and should be done just prior to refuse pickup
WASTE AUDIT Step 2. – Conduct a Waste Audit G ather the following materials and resources: sorting tables a large scale for weighing the waste separate bins for each sorting category gloves surgical masks a calculator materials for recording data
WASTE AUDIT Step 2. – Conduct a Waste Audit Safety First! Talk to your facility safety representative prior to doing a waste sort Wear protective clothing such as long-sleeved shirts, pants, gloves, and surgical masks If you discover any hazardous material, don’t touch it and contact your safety representative
WASTE AUDIT Step 2. – Conduct a Waste Audit Once you have transferred all of the garbage to your sorting table, identify the materials you generate (for example, cardboard, office paper, and food waste) Weigh each type of material and record your findings Total the different amounts of waste found in each dumpster to find the “bottom line” Do similar waste sorts within the facility to determine what size recycling containers you’ll need and where they should be placed
DECIDING WHAT TO RECYCLE Step 3. – Deciding What to Recycle Certain materials are either banned or restricted from from disposal facilities, such as: Tires Green Waste (yard trimmings) Appliances Used Oil Scrap Metal Auto Batteries Contact your landfill to find a listing of restricted materials and how these materials can be disposed
DECIDING WHAT TO RECYCLE Step 3. – Deciding What to Recycle In some municipalities, businesses are required to recycle certain commodities such as: Bars and restaurants serving alcoholic beverages might be required to recycle glass Office buildings might be required to recycle office paper, newspaper and cardboard Hotels, restaurants, food courts, grocery stores, hospitals, and food manufacturers who generate large volumes of food waste might be required to recycle food waste You should contact your local solid waste regulator to determine what materials you must recycle
DECIDING WHAT TO RECYCLE Step 3. – Deciding What to Recycle Target materials with reliable markets, such as: Aluminum Corrugated cardboard Used Oil Copper/Brass Office/Computer paper Tires Steel Newspaper Green Waste Glass
DECIDING WHAT TO RECYCLE Step 3. – Deciding What to Recycle The following liquids may be recycled and reused on your premises in most areas with special equipment: Solvents Antifreeze Frying oil
COLLECTION CONTRACTORS Step 4. – Selecting a Collection Contractor In selecting a collection contractor, you are looking for good, reliable service at the best price The prices paid for recyclable materials vary with the type of material and can fluctuate dramatically from month to month Moreover, your company’s economic benefit from recycling will probably come from reduced disposal costs, rather than money paid to you from the sale of recyclables
COLLECTION CONTRACTORS Step 4. – Selecting a Collection Contractor Option 1: Refuse hauler is also the recycling hauler If your refuse hauler provides both waste disposal and recycling collection, the hauler should be able to offer a combined cost/pay structure In other words, he would charge you for the hauling of both refuse and recyclables and credit you the current market value on the recyclables This can reduce your overall disposal costs or at least provide a break-even arrangement
COLLECTION CONTRACTORS Step 4. – Selecting a Collection Contractor Option 2: Recycling company picks-up A second option is to have a recycling company (or processor) collect and pay you for a material or collect it at no charge/no pay, depending on the current value of each material A small collector will most likely provide no charge/no pay service If you select a recycler, you should discuss lowering disposal costs with your refuse hauler, once your recycling program is underway
COLLECTION CONTRACTORS Step 4. – Selecting a Collection Contractor When you talk to the various companies to compare prices and services, ask the following questions to help you make your decision: What materials do you collect? What materials do you purchase, and how much is paid for each? Do you charge for collection of recyclables? If you’re picking up trash and recyclables, what will be the net savings in my disposal costs? Do you pick up on schedule or on call? If on schedule, how often? If on call, how much lead time is needed?
COLLECTION CONTRACTORS Step 4. – Selecting a Collection Contractor Do you provide collection and/or storage containers? Will you help us organize and promote our recycling program? Are you willing to sign a long-term agreement? (A one-year minimum is recommended.) What is the allowable level of contamination? What are your reporting and accounting procedures? How long have you been in business? Once you have made the selection, include the information you have gathered in a written agreement
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System KEY: MAKE IT AS SIMPLE AND EASY TO RECYCLE AS IT IS TO THROW AWAY! The goal is to design a collection system that is convenient for everyone and does not incur additional labor costs
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Recyclables should flow from individual employees to area collection containers or directly to central collection/storage Place area recycling containers in convenient locations normally frequented by employees Recycling containers should look distinctly different from trash containers Place regular trash cans nearby to avoid unwanted trash getting mixed in with the recyclables
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System At Desks Each employee usually gets their own small recycling tray or upright box for convenience When full, the employee empties the paper into the larger paper bins Trays and upright bins may be available from your municipality for free.
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Office Suites Some space is required in offices for recycling bins Based on weekly service, the rule-of-thumb for a white or mixed paper program is one 12-gallon container in each copy or printer area For a beverage bottle and can program, you need one lined container per kitchen area
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Dumpsters Most buildings have dumpsters for garbage Dumpster sizes are measured in cubic yards; one cubic yard is equal to about three toters Dumpsters are good for larger loads or bulky materials, such as cardboard They have lids which are easy to lock (which will protect materials from theft and or contamination if the dumpsters are located outside). Special garbage trucks are equipped to pick up and empty dumpsters automatically.
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Compactors Where space is limited, many buildings prefer to invest in compacting equipment Compactors come in a wide range of styles and sizes They can be rented or purchased and are often customized for a specific site or use Some of the investment can be recovered by disposal savings because you need less frequent garbage or recycling pick ups
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System To select the best containers for your needs, consider the following: durability, cost, capacity, ease of handling, and attractiveness Check with local vendors on the types and styles available While containers need to be convenient for everyone, you also need to consider the work involved in emptying them By keeping in mind the needs of both employees and custodial or maintenance people you will find an acceptable balance that works for everyone involved
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Transferring to Central Collection and/or Storage KEY: INTEGRATE RECYCLING COLLECTION WITH EXISTING SYSTEMS KEY: DISTRIBUTE THE RESPONSIBILITIES.
DESIGNING A RECYCLING SYSTEM Step 5. – Designing a Recycling System Central Collection/Storage Area Determine the best location for you with your building or facility manager and your collection contractor, using these guidelines: Is the site large enough? Is there easy access to freight elevators and loading docks? Does the area meet with local fire and building codes? Are sprinklers required/in place?
TRAINING AND PROMOTION Step 6. – Training and Promotion Phase 1: Program Announcement Announce the start of the program with a brief, upbeat memo from the head of the company The memo should highlight the benefits of the program to everyone, outline the collection procedure, and give the time for a meeting to formally introduce the recycling program and answer questions
TRAINING AND PROMOTION Step 6. – Training and Promotion Phase 2: Meeting/Educational Session Encourage everyone to attend an information session about the new program The meeting should focus on the cooperative nature of recycling and the importance of each individual to its continued success Highlight the main points of the program, taking care to explain the separation and collection procedures Emphasize the benefits to the environment, the company and the employees
TRAINING AND PROMOTION Step 6. – Training and Promotion Phase 3: Follow-Up Follow-up can be done as a part of a regular meeting agenda or with memos or newsletters Consistency is the key to any successful program, and recycling is no different Note how much is being taken out of the waste stream, how much was donated to charity, how big the party fund is, and so on
PROBLEMS AND SOLUTIONS Problem 1: Low Participation Rate Here are some of the things you can do to stimulate participation: Solution, Part 1: Provide Information People may not know how to recycle Provide reminders to tenants in memos and other promotional pieces Check that signs explain the recycling program See the Training and Promotion Section of this training
PROBLEMS AND SOLUTIONS Solution, Part 2: Put Containers in the Right Places Check the location of recycling bins Make sure there are enough of them and that they are conveniently located Make it easier to put recyclable materials in the recycling bins than to put them in the garbage Make sure everyone can easily reach a recycling bin
PROBLEMS AND SOLUTIONS Solution, Part 3: Appoint Recycling Experts It helps everyone to have an expert available to ask questions Designate motivated employees to be recycling coordinators for specific areas and let everyone know how to reach them Include the names or phone numbers for the experts in all the promotional materials
PROBLEMS AND SOLUTIONS Solution, Part 4: Motivate Some people simply don't care at all about recycling Some people are very busy and might consider recycling to be a waste of time that is better spent on their "real work" Some of these people can be convinced to participate by providing incentives, such as games, prizes, and recognition or by making recycling easier than not recycling You can also put recycling into contracts when doing business outside your company
PROBLEMS AND SOLUTIONS Problem 2: Contamination This is when non-recyclables are mixed with recyclables Solution: If contamination of recyclables is a problem throughout your building, ask your recycling company to help find procedural flaws or collection deficiencies If contamination is isolated to certain individuals in the building, focus your educational efforts on making sure they know the policies Solicit management help to change behavior
PROBLEMS AND SOLUTIONS Problem 3: Unauthorized Scavenging This is when people are stealing the recyclables. Solution: Provide a secure, central storage area for recyclable materials between pick ups It should be secured from public access, yet easily accessible to your custodial staff and the recycling company Inform cleaners when unauthorized scavenging takes place and ask them to report suspicious activities to management
PROBLEMS AND SOLUTIONS Problem 4: Lack of Space This can either be a lack of space near the points of generation or at the central collection and storage. Solution Lack of storage space is one of the biggest problems in many downtown office buildings Request assistance from your recycling company The two most practical solutions are to: (1) have materials collected more frequently and (2) install compacting equipment Be sure to consider health and safety as well as fire hazards when you address space issues
BUYING RECYCLED Closing the Loop Business must also support the purchase of recycled products By purchasing recycled products made with recycled materials, you are helping to ensure that a market will continue to exist for the materials collected in your recycling programs Building managers, through purchasing recycled products, can make a difference
BUYING RECYCLED Identifying Recycled-Content Products “Recycled-content products” are made from materials that would otherwise have been discarded (i.e. aluminum soda cans or newspapers) “Postconsumer content” refers to material from products that were used by consumers or businesses and would otherwise be discarded as waste. If a product is labeled "recycled content," the rest of the product material might have come from excess or damaged items generated during normal manufacturing processes—not collected through a local recycling program
BUYING RECYCLED “Recyclable products” can be collected and remanufactured into new products after they've been used There are more than 4,500 recycled-content products available, and this number continues to grow Make the commitment to “Close the Loop” and to purchase these products
Remember, You Control Your Facility or Area! Review Procedures With Them Before Starting the Job! Ensure They Are Properly Trained! Determine Their Environmental Compliance Record! Determine Who Is in Charge of Their People! Determine How They Will Affect Your Facility’s Environmental Compliance ! TIPS FOR USING CONTRACTORS
ELEMENTS OF A SUCCESSFUL SOLID WASTE RECYCLING PROGRAM DETAILED WRITTEN SOLID WASTE RECYCLING INSPECTION GUIDELINES. 2. DETAILED WRITTEN SOLID WASTE RECYCLING BEST MANAGEMENT PRACTICES. 3. EXTENSIVE EMPLOYEE TRAINING PROGRAMS 4. PERIODIC REINFORCEMENT OF TRAINING 5. SUFFICIENT DISCIPLINE REGARDING IMPLEMENTATION 6. PERIODIC FOLLOW-UP