Tzsa, 1 BK. SANITARY LANDF LL FACTS ------- SANITARY LANDFILL FACTS Thomas J. Sorg H. Lanier Hickman U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service NATIONAL CENTER FOR URBAN AND INDUSTRIAL HEALTH SolidWastes Program Cincinnati 1968 SW-4tS For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price 35 cents ------- Public Health Service Publication No. 1792 ------- FOREWORD For many years our polluted environment has been the object of growing concern. Water and air pollution have received national attention and treatment for a decade, but solid waste disposal, which has been called the third pollution, entered the national limelight only during the past two years with the passage of the Solid Waste Disposal Act of 1965. Public apathy toward the disposal of solid wastes is no longer com- monplace. In many communities, the public is rejecting the tradi- tional open burning dump. Citizens are recognizing the need for safe and sanitary management of solid wastes. Thus, the demand increases for properly engineered, effective, and economic solid waste disposal facilities. SANITARY LANDFILL FACTS presents general information on the state-of-the-art of one basic, acceptable, and effective method of solid waste disposal — the sanitary landfill. This publication ex- amines the planning, design, operation, and public health aspects of sanitary landfills. This information is offered as an aid to the growing number of people involved with planning and development in solid waste disposal management. Richard D. Vaughan Chief, Solid Wastes Program 111 ------- ------- CONTENTS MISCONCEPTION vii PLANNING A SANITARY LANDFILL 1 Competent Designer 1 Public Information Program 1 Other Considerations 2 SELECTING A SITE 2 Land Requirement 2 Zoning Restrictions 3 Accessibility 3 Haul Distance 3 Cover Material 3 Geology 3 Climate 4 Fire Control Facilities 4 DESIGNING A SANITARY LANDFILL 4 Plans 4 Specifications 5 OPERATING A SANITARY LANDFILL 5 Supervision 5 Operating Records 5 Directions 5 On-site Roads 6 Methods 6 Compaction 8 Working Face 8 Depth of Cells 8 Cover 8 Large Bulky Items 8 Landfilling (Photographs) 9 Blowing Paper 13 Maintenance 13 Drainage 13 Winter Operations 13 Wet Weather Operation 13 Salvage Operation 14 PUBLIC HEALTH AND NUISANCE ASPECTS 14 Vector Control 14 v ------- Water Pollution 14 Air Pollution 14 Dust 14 Odors 15 Wildlife 15 Gas Production 15 Hazardous Materials 15 EQUIPMENT 15 Type 15 Size 17 Amount 17 FACILITIES 18 COSTS 18 Initial Investment 18 Operation Cost 18 COMPLETED SANITARY LANDFILL 20 Decomposition 20 Settlement 20 Underground Fires 20 Maintenance 20 Uses 20 ADVANTAGES 21 DISADVANTAGES 21 PHS SANITARY LANDFILL PROJECTS 22 REFERENCES 22 BIBLIOGRAPHY 23 VI ------- * ^'r**,.i*5wr :~-£ -r These photographs demonstrate how open dumps contribute to water and air pollution. Open dumps are also sources of food and harborage for insects, rodents, birds, and o'ther wild- life that may act as disease carriers. MISCONCEPTION Upon hearing the term, 'san- itary landfill, ' many of us im- mediately picture the tradition- al open, frequently burning, dump. This misconception is quite natural because in many in- stances the term 'sanitary landfill' has been misused as the label for an open dump. The fact is, however, that a true sanitary landfill is not an open dump. ------- ------- SANITARY LANDFILL FACTS The sanitary landfill is defined by the American Society of Civil Engineers as: "A method of disposing of refuse on land without creating nuisances or hazards to public health or safety, by utilizing the principles of engineering to confine the refuse to the smallest practical area, to reduce itto the smallest practical volume, and to cover it with a layer of earth at the conclusion of each day's operation, or at such more frequent intervals as may be necessary. "•* Such a landfill is a well controlled and truly sanitary method of disposal of solid wastes upon land. It consists of four basic operations: (1) The solid wastes are deposited in a controlled manner in a prepared portion of the site; (2) the solid wastes are spread and compacted in thin layers; (3) the solid wastes are covered daily or more frequently, if nec- essary, with a layer of earth; (4) the cover material is compacted daily. The final result can be a golf course or play- field as suggested on the cover design of this booklet. PLANNING A SANITARY LANDFILL A sanitary landfill is an engineering project. When sound engineering prin- ciples are applied, the result will be a successful operation and in most cases will save money. Most operational prob- lems can be prevented iri the initial de- velopment stages. This is easier and more economical than correcting the de- fects once the operation has begun. The first step toward the ultimate goal of establishing a sanitary landfill opera- tion, of course, is the initial planning phase. The preliminary planning devel- ops the basic groundwork for the actual engineer ing phases of site selection, de- sign, and operation. Advanced planning should include consideration of: a com- petent designer; apublic information pro- gram; a survey of solid waste practices and possible sites; the method of financ- ing; the ultimate use of the completed site; and site zoning arrangements. Competent Designer Engineering knowledge and experience in sanitary landfill site selection, design, and operation are essential requirements of the individual or agency chosen to de- velop the sanitary landfill. If the plan- ning or operating agency does not have this engineering experience and compe- tence, every effort should be made to ob- tain the services of the best engineering consultant available. Although a sanitary landfill is considered the most inexpen- sive of the approved methods of disposal, it is a mis take to assume that a success- ful operation requires little skill or knowledge of design and operation. The selection of an engineer or consultant is a poor place to attempt to economize. The money spent for the services of a competent designer will be realized in a sanitary landfill operation which is suc- cessful and acceptable to the public. Public Information Program Unfortunately, many citizens associ- ate impressions of open burning dumps 338-532 O - 69 - 2 ------- with sanitary landfills. Usually the plan- ning of a sanitary landfill meets with some public opposition unless the operat- ing agency has conducted acceptable op- erations elsewhere. Preliminary planning should include an active public information program to explain to the public what makes a sani- tary landfill work well and what benefits can be expected. In many communities, public acceptance of a sanitary landfill site is the most important factor in de- ciding whether it will exist--or not. Moreover, it is very useful in gaining public support and most helpful to a de- signer to have the final use of the landfill area determined in advance. An archi- tectural rendering or a model of the com- pleted site, as a park, playground, golf course, or other planned use, is a good public relations tool. When opposition is exceptionally strong to the proposed sani- tary landfill, it is well to consider the installation of a temporary pilot opera- tion to illustrate a good sanitary landfill, while soliciting newspaper and TV sup- port and possibly even hiring profession- al public relations services for the pro- gram. It is well to remember, however, that the public will soon discover any discrepancies between the public infor- mation program and actual operations. Operations must be exemplary in order to gain public support. Other Considerations The responsible officials in the pre- liminary planning phase must decide how the initial cost and the operating costs of the sanitary landfill will be financed. These officials should also investigate the amount and reliability of available data concerning the quantity and charac- teristics of the solid wastes to be handled. If sufficient and reliable data necessary for proper site selection and design are not available, arrangements should be made to survey the area generating solid wastes to procure the necessary infor- mation. If at all possible, the ultimate use of the completed landfill site should be decided during the initial planning stage. As stated previously, knowing the final use of the site will permit the designer to plan more effectively and will be useful for gaining public support for the project. In many instances, zoning restrictions have interfered with the de- velopment of an area for a sanitary land- fill. Many legal problems can be avoided if preliminary planning includes arrange- ments for zoning potential areas for san- itary landfill operations and ultimate site use. SELECTING A SITE An important engineering step toward establishing an acceptable sanitary land- fill operation is site selection. As with the preliminary planning phase, proper site selection can eliminate many future operational problems. Most of the many factors to be considered when selecting a sanitary landfill site will require tech- nical know-how, a knowledge of equip- ment, and experience, and so it bears repeating that a well qualified individual or agency should be responsible for site selection. Land Requirement The land area--or more important the volume of space required--is primarily dependent upon the character and quantity of the solid wastes, the efficiency of com- paction of the wastes, the depth of the fill, and the desired life of the landfill. Data on the quantity and character of res- idential, commercial, and industrial sol- id wastes to be landfilled are therefore necessary for estimating the space re- quired. In estimating volume require- ments, volume reduction of the solid wastes due to compaction must be con- sidered. The desired life of the landfill ------- is another major factor in determining the total volume required. The volume requirement for a sani- tary landfill should be determined using the specific data and information avail- able for each individual project. As a rough rule of thumb, however, about 7 acre-feet (11,293 yd3) per 10,000 popu- lation per year is frequently used. Zoning'Restrictions A survey conducted by the American Public Works Association in 1956 indi- cated that a high percentage of cities are restricted in the acquisition of disposal sites by their zoning ordinances. 2 Con- sequently, before a full-scale investiga- tion of a potential site is undertaken, all zoning ordinances should be reviewed and cleared or changed to eliminate any le- galities which could prevent or indefinite - ly hold up the use of a particular parcel of land for a sanitary landfill. Advance planning to zone the potential landfill site areas for sanitary landfill operation can circumvent many of these problems. Accessibility It is important to select a site that truck traffic can easily reach on high- ways or arterial streets. Sites requir- ing the trucks to travel through residen- tial areas will normally draw many complaints, and such sites should be avoided. The roads to the site should be of such width and construction to handle all sizes of trucks when fully loaded, during all weather conditions. Such problems as narrow bridges, low underpasses, and steep grades on the access routes should also be investigated. Since the site should be accessible at all times, it is desirable to have several access routes so that if one route is temporarily un- usable the site can still be used. Haul Distance The haul distance is an important ec- onomic factor in selection of the sanitary landfill site. The economic distance to the site will vary from locality to locality depending upon capacity of collection ve- hicles, hauling time, and size and meth- ods of the collection agency. The larger the quantity of refuse hauled per trip and the shorter the hauling time due to ex- press roads, freeways, etc. , the greater the distance the solidwastes canbe hauled for the same cost. Cover Material The availability of cover material is another economic factor to consider when choosing the site, for the cost of hauling cover material to the site can be exces- sive. It is desirable, therefore, to se- lectasite that has cover material avail- able or close by to keep these costs at a minimum. The field investigation of the potential site should include soil analysis to de- termine the suitability and the quantity of soil available for cover material. Soil with good workability and compaction characteristics is the most desirable cover material. Sandy loam is consid- ered to' be excellent since it contains about 50 to 60 percent sand and the re- mainder is clay and silt in equal amounts with good workability and compaction qualities. Geology The potential danger of ground and surface water pollution resulting from the landfill cannot be overlooked. Solid wastes ordinarily contain many contam- inants and often infectious materials. These can produce serious health haz- ards or nuisances if permitted to enter water supplies. Site selection should in- clude a geological investigation of the site, which can be run in conjunction with the ------- cover material field investigation, to de- termine the potential of either ground or surface water pollution. The ground water table mustbe located and informa- tion obtained on the historical high ground water level and on the general movement of the ground water. The geological investigation should also examine the topography of the site itself and the surrounding area for poten- tial flooding conditions of the site during heavy rains and snow melts. Flooding and surface water drainage can quickly erode the cover material and the refuse fill. Special attention should be given to low-lying sites that might be drainage basins for surrounding areas. Sites lo- cated near rivers, streams or lakes also deserve careful scrutiny. Generally, a landfill should not be located in a flood plain because of the water pollution haz- ard, and because such sites are unusable both during, and for a period following, flood conditions. Climate In some locations, climate conditions are important considerations in site se- lection and may even dictate the method of operation. In an extremely cold local- ity, a site requiring excavation of trench- es and cover material may become a problem because of the frost during the winter months. However, a site requir- ing excavation operations can be used in awintery locale if special operating pro- cedures are planned in advance to cope with the expected problems; the trenches and cover material may be excavated during the summer months to carry the operation through the winter period. In areas receiving considerable rain- fall, a low-lying site may not be desir- able because of flooding and continual muddy working conditions. In rainy areas, a site high in relation to the sur- rounding area, with good drainage fea- tures, is desirable. In windy locales, a site surrounded by natural windbreaks will help to contain loose paper, thus reducing the amount of this material which may be blown off the site. Fire Control Facilities Although there is little chance of fire at a sanitary landfill when operated in accordance with good practices, a sani- tary landfill site should be provided with suitable fire protection. Despite the fact that fires can usually be extinguished by smothering with a blanket of earth, all sites should have water available for fire control. Special consideration for fire control facilities should be given to san- itary landfills located relatively close to residential or commercial structures and in extremely dry areas where the fire could spread quickly and do extensive damage if not brought under control im- mediately. DESIGNING A SANITARY LANDFILL The design and operational steps dur- ing development of the sanitary landfill are not distinct phases. Basic knowledge and experience in the operational aspects of a sanitary landfill are necessary for the design phase. In essence, the design phase develops the plan of operation. It consists primarily of determining the operational plan and preparing the nec- essary detailed plans and specifications for construction and operation. Good plans and specifications are essential for estimating costs, bids for contracts, and for operational control and inspection. Plans Detailed plans should be prepared showing the existing topography and the designed contours of the completed land- ------- fill. As mentioned above, in the planning section, it is extremely helpful to the de- signer when designing the final ground elevations, if the use of the completed landfill has been previously determined. The plans should show the overall plan for landfilling, the drainage features , lo- cation of the cover material, and the wet weather operation site. The plans should also detail all construction features such as access roads, personnel and equip- ment facilities, scales, fencing, signs, waterlines and other utilities. Specifications The plans should be complemented with a set of specifications for construc- tion and operation. Construction specifi- cations cover the construction materials, workmanship, and equipment. The oper- ating specifications should detail the method of operation including the weigh- ing of the wastes, the cross sectioning of the site at definite time intervals, the thickness of cover material, the depth of lifts and cells, compaction, and wet weather operation procedures. OPERATING A SANITARY LANDFILL The importance of the appearance of the sanitary landfill during operation can- not be overly stressed. The operation is the only phase of the project that is seen by the public. Consequently, public ac- ceptance of the entire project—the plan- ning, design, and operation--will be based solely on the operation. There are many factors involved in the operation of a sanitary landfill. A well operated sanitary landfill is the goal of the planner, designer, and operator and, therefore, each must have a thor- ough knowledge of all the factors to guide him in achieving this goal. Supervision A clean, orderly, and economic oper- ation requires constant and competent supervision. It is also important to em- ploy only experienced or adequately trained personnel to operate a sanitary landfill. Operating Records For continuing evaluation and future planning, detailed records should be kept of the sanitary landfill operations. Rec- ords should be kept of the incoming mate- rial: the weights, the type, and the ori- gin. Any deviation from the plan of operation should also be recorded. Top- ographic surveys of the landfill should be made regularly to determine the rate of space utilization. The incoming-mate- rial data and the topographic surveys can be used to determine the amount of ma- terial generated per capita, compaction, land use, operation efficiency, and to es- timate the degree of decomposition and eventual settlement. Good cost-account- ing records should be maintained, includ- ing the initial cost of the land and equip- ment, and the operating cost of the labor, equipment, equipment maintenance, de- preciation, etc. These data are neces- sary for budgetary planning, for deter- mining the cost rates for users, and for comparisonwith other operations, justi- fying expenditures, and estimating the efficiency of operation. Directions Sanitary landfills, particularly those open to the public, need directional signs and markers on nearby highways to help speed traffic movement. At the entrance to the site, a large legible sign should be posted to inform the public of the hours of operation, cost of disposal, and rules and regulations (such as, "only covered ------- THE AREA METHOD The bulldozer is spreading and compacting a load of solid wastes I" The scraper (foreground) is used to haul the cover material at the end of the day's operations. Note the portable fence that catches any blowing debris; these are used with any landfill method, whenever necessary. trucks permitted"). At large sanitary landfill operations, signs should also be used on the site to direct the users to the unloading area. On—site Roads The on-site roads to the unloading area should be of all-weather construc- tion and wide enough to permit easy two- way truck travel. Road grades should be designed for the largest fully loaded trucks to travel at a reasonable rate. It is particularly important at large sites that traffic in and out of the area should flow smoothly. Methods Sanitary landfilling consists of the ba- sic operations of spreading, compacting, and covering. Over the years, two gen- eral methods of landfilling have evolved: the area method, and the trench method. Some schools of thought also mention a third, the slope, or ramp, method. In many operations, a slope, or ramp, is used in combination with the area or trench methods . For this reason, three methods will be described: area land- fill, trench landfill, and the ramp, or slope, method,. In the area landfill, the solid wastes are placed on the land; a bulldozer or sim- ilar equipment spreads and compacts the wastes; then the wastes are covered with a layer of earth; and finally the earth cover is compacted. The area method is best suited for marshes, flat areas, or gently sloping land and is also used in quarries, ravines, valleys or where oth- er suitable land depressions exist. Nor- mally, the earth cover material is hauled in or obtained from adjacent areas. In a trench landfill, a trench is cut in the ground and the solid wastes are placed in the trench. The solid wastes are then spread in thin layers, compacted, and covered with earth excavated from the trench. The trench method is best suited for flat or gently sloping land where the water table is not near the ground surface. The advantage is that normally the ma- terial excavated from the trench can be used for cover with a minimum of haul- ing. A disadvantage is that more than ------- THE TRENCH METHOD The waste collection truck deposits its load into the trench where the bulldozer will spread and compact it. At the end of the day the dragline will excavate soil from the future trench, and this soil will be used as the daily cover ma- terial. Trenches can also be excavated with a front-end loader, bulldozer, or scraper. one piece of equipmentmay be necessary. In the ramp or slope method (a varia- tion of the area and trench landfills), the solid wastes are dumped on the side of an existing slope. After spreading the ma- terial in thin layers on the slope, the bulldozing equipment compacts it. The cover material, usually obtained just ahead of the working face, is spread on the ramp and compacted. As a method of landfilling, this variation is generally suited to all areas. Having the advantage of utilizing only one piece of equipment to perform all operations makes the ramp or slope method of landfill particularly applicable to smaller operations. The slope, or ramp, is commonly used in the area and trench landfill and is illustrated below. THE RAMP VARIATION The solid wastes are being spread and compacted on a slope. The daily cell may be cov- ered with earth scraped from the base of the ramp. This variation is used with either the area or trench method. ------- Compaction Solidwastes should be placed at the top or base of the working face, spread in thin layers about 2 feet thick, and compac- ted. If a slope, or ramp, is used, better compaction will normally result if the wastes are spread and compacted from the base upwards. The degree of com- paction is dependent on the character of the solid wastes, the weight and type of compacting equipment, and the number of passes the equipment makes over the ma- terial. The actual density of the landfill can be determined from operating rec- ords and data. The degree of compaction is a useful tool to determine the rate of space usage, expected life of the land- fill, and the overall efficiency of the operation. Working Face The size of the working face of the landfill operation is determined by the rate of unloading of the incoming vehicles. The working face should be as narrow as possible to minimize the exposed area, but not so small as to interfere with the unloading operations and the movement of landfill equipment. A minimum width of the working face should be approxi- mately twice the width of the tractor to allow the tractor to move from side to side thus compacting the entire exposed surface. Depth of Cells Cell depth is the thickness of the solid wastes layer measured perpendicular to the working slope where the equipment travels. The depth of cells is determined largely by the size of the operation, the elevation desired of the completed fill, the depth of the trench or depression to be filled, and in some cases, the amount of cover material available. Eight feet is generally recommended as a maximum single cell depth because deeper cells usually result infills that have excessive settlement and surface cracking. How- ever, the cell depth of presently operated sanitary landfills varies from 2 feet to 15 feet or more. Cover The compacted solid wastes should be covered at the conclusion of each day's operation, or more frequently if neces- sary, with a minimum of 6 inches of compacted earth. Because of its work- ability and compaction characteristics, a sandy loam soil is the most desirable cover material. But if sandy loam is not available on the site, itmay be necessary to adjust the covering procedures to the type of cover material available or to haul in more suitable cover material. The cover is necessary to prevent insect and rodent infestation, blowing paper, fires, the attraction of gulls, and the re- lease of gas and odors. For daily cover, a minimum of 6 inch- es of compacted sandy loam is recom- mended. For intermediate cover on lifts which will not have additional lifts placed on them within a year, a minimum of 12 inches of compacted sandy loam is rec- ommended. A minimum of 2 feet of com- pacted sandy loam is recommended for the final cover. The final cover should be placed over the fill as soon as possible to help assure that wind and water ero- sion does not expose the wastes. Where trees will be planted on the completed fill, a depth of 3 or more feet of com- pacted earth has been found necessary. Large Bulky Items Large bulky items such as car bodies, refrigerators, water heaters, and tree stumps, can be handled routinely with other solid wastes at large landfills that use heavy equipment. At small landfills ------- STEPS IN OPERATING A SANITARY LANDFILL Unloading Solid Wastes 338-532 O - 69 - 3 ------- 10 Spreading and compacting of refuse followed by earth covering ^ , .. , " ------- 11 ,<***. ------- 12 End of the day .4* ------- 13 where light equipment is normally used, special provisions may be necessary to handle bulky items. A separate unload- ing area at the site or an alternate site, operated in a sanitary manner, should be utilized for the disposal of bulky items that cannot be handled routinely with the other solid wastes. Blowing Paper In a 1959 survey of sanitary landfill operations by the American Society of Civil Engineers, the operating problem most frequently reported was that of blowing paper. 3 The common method of controlling blowing paper is with a com- bination of permanent and portable fences. Unfortunately, under certain wind condi- tions the paper may blow up and over the fences, so that fences do not provide complete control. Prompt compaction and covering are also useful in control- ling windblown paper. It is important, therefore, that the designer consider the prevailing wind direction when designing the operation. Maintenance Routine maintenance will be required to maintain a clean, orderly, and accept- able operation and site. It is important, particularly at public sanitary landfills, to cut the grass and weeds, pick up the scattered paper, maintain good access roads, control dust, and maintain clean and attractive employee and public facil- ities. Drainage To prevent ponding on the landfill sur- face with resultant excessive seepage in- to the landfill, drainage must be pro- vided. This will prevent runoff water from eroding the cover material and ex- posing the wastes. Drainage must be provided both during the filling operation and for the completed landfill. Good drainage will usually require periodic re- grading of the site, and the use of cul- verts or grassed waterways. It is rec- ommended that the slope of the surface of the completed fill be a minimum of 1 percent. Since the landfill will undergo uneven settlement, it may be necessary to design the original slope for more than 1 percent to maintain a 1 percent slope after settlement. To prevent erosion, however, steep slopes should be avoided. Winter Operations Experience has shown that with good planning and proper operating techniques, a sanitary landfill can be operated throughout even the severe winters of North Dakota. Where the trench method of landfill is used, the trenches should be excavated before the cold weather season. It may be necessary to stockpile cover material and cover it with straw, leaves, or other material to prevent freezing. The material should be piled loosely with minimum compaction. All snow and ice should be removed from the trenches be- fore use; it is good practice to use snow fences to protect the access roads. Also, a well-constructed, heated, tractor cab enables the operator to work efficiently during the cold weather. Wet Weather Operation Wetweather can seriously hamper the operations of a sanitary landfill by mak- ing the soil too soft, mucky, or slippery for equipment operation. Wet weather can also seriously interfere with trench- ing, covering, and general traffic flow to and from the working face. For these reasons, all-weather access roads and drainage should be built. In many cases, it is advantageous to stockpile such ma- terials as concrete rubble, broken as- ------- 14 phalt pavement, stone, etc. , for use on the site roads during wet weather. This will minimize the cost of constructing and maintaining hard-surface roads to the unloading area. It is also desirable to provide a temporary wet weather land- fill area adjacent to the all-weather road. Such sites are used only during the wet weather periods when the normal working area is not accessible. Particular attention must be given to landfills when the trench method is being used. If pumping or good drainage is not provided, the trenches will fill with water, resulting in possible ground or surface water pollution and complete shut-down of the operation. Salvage Operation The American Society of Civil Engi- neers has stated that generally the most objectionable disposal sites from the standpointof appearance are those where the salvage activity is the greatest. 1 To ensure clean and orderly sites and to prevent landfills from looking like open dumps, salvage operations shouldbe pro- hibited at all sanitary landfill sites. PUBLIC HEALTH AND NUISANCE ASPECTS Vector Control In a properly operated and maintained sanitary landfill, insects and rodents are not a problem. Well-compacted wastes and cover material are the most impor- tant factors in achieving vector control. Six inches of compacted earth cover is recommended for preventing the emer- gence of houseflies from the fill. Good compaction of the cover material also discourages rodents from burrowing through the cover material. Good house- keeping and daily covering of the solid wastes are musts for vector control. Water Pollution Under certain geological conditions, the burial of solid wastes is a real poten- tial for chemical and bacteriological pol- lution of ground and surface water. Sev- eral investigations of the pollution of ground water from sanitary landfills have indicated that if a sanitary landfill is in- termittently or continuously in contact with ground water, the ground water can become grossly polluted and unfit for do- mestic or irrigational use. Proper plan- ning and site selection, however, com- bined with good engineering design and operation of the sanitary landfill can nor- mally eliminate the possibility of either surface or ground water pollution. Some of the common preventative measures used are: (1) locating the site at a safe distance from streams , lakes, wells, and other water sources; (Z) avoiding site location above the kind of subsurface stratification that will lead the leachate from the landfill to water sources, i. e. , fractured limestone; (3) using an earth cover that is nearly impervious; (4) pro- viding suitable drainage trenches to carry the surface water away from the site. Air Pollution Air pollution caused by smoke should not occur. No burning should be permit- ted at a properly operated sanitary land- fill. If a fire does occur, it should be extinguished immediately. Dust Dust is a nuisance that may occur at a sanitary landfill operation in dry weather. Dust generated at the unloading area can be controlled by sprinkling the unloading area and the deposited refuse with water. Other dust control measures are the planting of grass or other vegetation on the finished fill and the application of ------- 15 water, road oil, or calcium chloride to the access roads. Odors Odorous gases usually result irom anaerobic digestion of putrescible material. The best con- trol for odors is rapid and continuous coverage of solid wastes during the day and sealing surface cracks of the com- pleted area of the landfill to prevent emis - sions of large concentrations of odorous gases. Wildlife Birds, particularly gulls, and other wildlife are common at open and burning dumps. There is little exposed food to attract wildlife at sanitary landfills. Most good sanitary landfill operations are free from these nuisances; however, there is no guarantee that all sanitary landfills will be completely free of wild- life. To keep the number of gulls and other wildlife to a minimum, the site should be kept clean, and the solid wastes should be covered promptly with earth. Gas Production Gas produced within a sanitary land- fill consists chiefly of methane, nitrogen, carbon dioxide, hydrogen, and hydrogen sulfide. Methane gas is explosive and can be a hazard if accumulated in enclosed spaces. At landfills where methane and other gases are a problem, the gases should be dissipated into the atmosphere. Hazardous Materials Although it is not common practice, hazardous materials such as sewage solids, radioactive wastes, pathologic wastes, explosive materials, and chem- icals can be disposed of at landfill sites under special conditions. The special provisions for handling and disposing of these materials will depend on local con- ditions. These materials may require individual handling and disposal in a spe- cial area separate from the main oper- ating area. The necessary provisions should be considered during the design phase and, if appropriate, be included in the operational specifications. EQUIPMENT A wide variety of equipment is on the market today from which to select the proper type and size needed for an effi- cient operation. The size, the type, and the amount of equipment required at a sanitary landfill depend on the size and method of operation and to some degree on the experience and preference of the designer and equipment operators. Type The most common equipment used on sanitary landfills is the crawler or rub- ber-tired tractor. The tractor can be usedwith a dozer blade, trash blade, or a front-end loader. A tractor is versa- tile and can normally perform all the op- erations: the spreading, compacting, covering, trenching, and even the haul- ing, of the cover material. The decision on whether to select a rubber-tire or a crawler-type tractor, and a dozer blade, trash blade, or f ront-end loader, must be based on .the existing conditions at each individual site. Other equipment used at sanitary land- fills are scrapers, compactors, drag- lines, rippers, and graders. This type of equipment is normally found only at large sanitary landfills where specialized equipment increases the overall efficien- cy. ------- 16 STANDARD LANDFILL EQUIPMENT n L H 3 CRAWLER TRACTOR RUBBER-TIRED TRACTOR FRONT-END ACCESSORIES BUCKET DOZER BLADE MULTIPURPOSE BUCKET LANDFILL BLADE SPECIALIZED EQUIPMENT SCRAPER DRAGLINE STEEL-WHEEL COMPACTOR ------- 17 Size The size of the equipment is dependent primarily on the size of the operation. Small sanitary landfills for communities of 15, 000 people or less or sanitary land- fills handling 40 tons of solid wastes per day or less can operate successfully with one tractor of the 5- to 15-ton range. Heavier equipment in the 15- to 30-ton range or larger can handle more refuse and achieve better compaction. Heavy equipment is recommended for sanitary landfill sites serving more than 15,000 people or handling more than 40 tons per day. Amount Sanitary landfills servicing 50,000 people or less or handling about 115 tons or less of solid wastes normally can man- age well with one piece of equipment. At these small sites where only one piece of equipm'ent is used, provisions must be made for standby equipment. It is pref- erable that a second piece of equipment be purchased and used for replacement during breakdown and routine mainte- nance periods of the regular equipment. Arrangements can normally be made, however, with another public agency or private concern for the use or rental of replacement equipment on short notice in case of a breakdown of the regular equipment. At large sanitary landfills serving more than 100,000 people, or handling more than 260 tons of solid wastes per day, more than one piece of equipment will be required. At these sites, spe- cialized equipment can be utilized to in- crease efficiency and minimize costs. Table 1 is offered as a general guide for the selection of the type, size, and amount of equipment for various sizes of sanitary landfills. Table 1. AVERAGE EQUIPMENT REQUIREMENTS Equipment Population Daily tonnage ~ ~ ~ ~~ ^ * 5 No. Type Size in Ibs 0 to 15,000 0 to 40 1 Tractor crawler or 10,000 to 30,000 rubber-tired 15, 000 to 50, 000 40 to 130 1 Tractor crawler or 30, 000 to 60, 000 rubber-tired * Scraper Dragline Water truck rubber-tired or more =!= Scraper Dragline Water truck 100, 000 260 2 Tractor crawler or 45, 000 or more or more or more rubber-tired or more '•; Scraper Dragline Steel wheel compactor Road grader Water truck Accessory"!1 Dozer blade Front-end loader ( 1 to 2 yd) Trash blade Dozer blade Front-end loader (2 to 4 yd) Bullclam Trash blade Front-end loader (2 to 5 yd) Bullclam Trash blade Dozer blade Front-end loader Bullclam Trash blade •^Optional. Dependent on individual ------- 18 FACILITIES Small sanitary landfill operations will usually require only a small building for storing hand tools, equipnnent parts , etc., and a small shelter with sanitary facili- ties for the employees or a single build- ing to serve both purposes. Large sanitary landfill operations should have a maintenance and storage garage for the equipment, and an admin- istrative-type building. If the scales are not adjacent to the administrative build- ing, a scale house may also be needed. Sanitary facilities should be available for both employees and the public. In addi- tion, it is recommended that locker rooms and showers be provided for the employ- ees. COSTS The cost of a sanitary landfill consists of the initial investment for land, equip- ment, and construction features, and the operating costs. Initial Investment The magnitude of the initial investment depends on the size and sophistication of the landfill. A typical breakdown of the items that will normally make up the ini- tial investment is as follows: 1. Land 2. Planning and designing a. Consultant b. Solid wastes survey c. Site investigation d. Design, plans, specifications 3. Construction a. Access roads b. Utilities--water, electricity, telephone, etc. c. Shelter and storage facilities d. Scales e. Fencing f. Miscellaneous--signs, site clearing 4. Equipment Generally, the major portion of the ini- tial investment will be for the purchase of the land and equipment. Often a size- able part of the initial investment for land and equipment can be recovered through the development or use of the land and the salvage value of the equipment. If moneys are not available for the proposed investment, consideration should be made of leasing either the land or equipment or both to spread the cost over the operation. Operation Cost The operating cost of a sanitary land- fill depends on the cost of labor and equipment, the method of operation, and the efficiency of the operation. The prin- cipal items that make up the operating cost are as follows: 1. Personnel—salaries and fringe benefits 2. Equipment a. Operating expenses—gas, oil, etc. b. Maintenance and repair ------- 19 c. Rental, depreciation, or amor- tization 3. Cover material--material and haul costs 4. Administration and overhead 5. Miscellaneous --tools , utilities, insurance, maintenance to roads, fences, facilities, etc. Labor wages will amount to about 40 to 50 percent of the total operating cost. Equipmentwill make up 30 to 40 percent; cover material, administration, over- head, and miscellaneous will amount to about 20 percent. Figure 1 charts the operating costs per tonversus the amount of solid wastes handled in tons and the population equiv- alent. The unit operating cost of a small operation handling 50, 000 tons per year or less varies from $1.25 to approxi- mately $5.00 per ton. This wide range is primarily due to the low efficiency of the smaller operations which are normal- ly operated on a part-time basis. Full- time personnel, full-time use of the equipment, specialized equipment, bet- ter management, and other factors that lead to high efficiency are possible at large sanitary landfill operations. The increased efficiency results in lower unit cost of disposal. The unit cost of a large landfill handling 50, 000 tons or more per yearwill generally fall between $0.75 to $2. 00 per ton. To compare the true cost of sanitary landfilling with that of incineration or composting, it is essential that the costs and returns of the initial investments and the hauling costs be included along with the disposal costs. The hauling costs of a collection system that uses the sanitary landfill disposal method may be higher than the hauling costs of a system using 3.C 2.00 0 I TONS PER YEAR 0 TONS PER DAY1 0 POPULATION2 0 100,000 200,000 300,000 400,000 500,000 320 640 960 1280 1600 122,000 244,000 366,000 488,000 610,000 'Based on 6-day work week. 2Based on national average of 4.5 Ibs per person per calendar day. FIGURE 1. SANITARY LAISDULL OPERATING COSTS ------- 20 incineration or composting, since sani- tary landfills are generally located fur- ther from the waste-generating area than are incinerators or compost plants. In contrast to the possibility of higher haul- ing costs, a sanitary landfill may in- crease the value of a plot of unusable land by converting the site to a playground, golf course, park, etc. , thereby obtain- ing a major investment cost advantage over incineration and composting. COMPLETED SANITARY LANDFILL Decomposition Information available on the decompo- sition of buried material in a sanitary landfill indicates that it is extremely dif- ficult to predict the time required for complete decomposition. Many items, particularly paper, have been found un- changed in landfills that had been com- pleted for 15 to 25 years. The rate of decomposition is primarily dependent up- on the moisture content and generally takes place at a very slow rate. Decomposition of the wastes will re- sultin the production of gases, principal- ly methane, carbon dioxide, nitrogen, hydrogen, and hydrogen sulfide. The amount of gas produced during any time interval is dependent upon the rate of gas production; it will usually reach a peak within the first 2 years and then slowly taper off. Methane gas causes the most concernbecause of its explosive charac- ter. Precautions should be taken to pre- ventthegas from seeping into sewers or other structures located on or near the landfill. Settlement Settlement of the landfill is dependent on the depth of the fill, composition, com- paction of the material, moisture con- tent, and other factors. Studies have in- dicated that approximately 90 percent of of the total settlement will occur in the first 2 to 5 years. The final 10 percent will occur over a long-range period. Underground Fires Although underground fires rarely oc- cur in a completed landfill, the possibility does exist. AIL underground fires should be dug up and extinguished. The cell con- struction feature of a sanitary landfill helps to confine and restrict the spread of the fire should one occur. Maintenance Completed landfills will generally re- quire maintenance because of differential settlement. The maintenance will con- sist primarily of resloping the surface to maintain good, drainage and filling in small depressions that result from un- even settlement. Uses Most completed landfill sites are used for recreational purposes such as parks, playgrounds, and golf courses. Comple- ted landfills are also used for parking and storage areas and botanical gardens. Because of settling and gas problems, construction of buildings on completed landfills generally has been avoided; in several locations, however, one-story rambling-type buildings and airport run- ways for light aircraft have been con- structed directly on sanitary landfills. In such cases, it is important for the de- signer to avoid concentrated foundation loading which can result in uneven settle- ment and cracking of the structure; and the designer must provide the means to allow the gas to dissipate to the atmo- sphere and not into the structure. How- ever, multi-store buildings can be built over completed landfills, using steel and concrete pilings and special engineering design. ------- 21 ADVANTAGES DISADVANTAGES The sanitary landfill has many advan- tages not common to other methods of disposal. 1. Where land is available, the sani- tary landfill is usually the most ec- onomical method of solid waste dis - posal. 2. The initial investment is low com- pared to that of other disposal methods. 3. A sanitary landfill is a complete or final disposal method as compared to incineration and composting where residue, quenching •water, unusable materials, etc., remain and require further disposal. 4. A sanitary landfill can be put into operation within a short period of time. 5. A sanitary landfill can receive all types of solid wastes , eliminating the necessity of separate collec- tions. 6. A sanitary landfill is flexible; in- creased quantities of solid wastes canbe disposed of with little addi- tional personnel and equipment. 7. Submarginal land may be reclaimed for use as parking lots, play- grounds, golf courses, airports, etc. 1. In highly populated areas , suitable land may not be available within ec - onomical hauling distance. 2. If proper sanitary landfill stand- ards are not adhered to, the opera- tion may result in an open dump. 3. Location of sanitary landfills in residential areas can result in ex- treme public opposition. 4. A completed landfill will settle and require periodic maintenance. 5. Special design and construction mustbe utilized for buildings con- structed on completed landfill be- cause of the settlement factor. 6. Methane, an explosive gas, and the other gases produced from the de- composition of the wastes may be- come a hazard or nuisance problem and interfere with the use of the completed landfill. ------- 22 PHS SANITARY LANDFILL PROJECTS The Solid Waste Disposal Act of 1965 provided funds for surveys, demonstra- tions, studies, and investigations of new and improved technology of solid waste disposal. The Act authorized awards up to two-thirds the cost of the project and the awards are made by the Solid Wastes Program, National Center for Urban and Industrial Health, U.S. Public Health Service. A recent publication describing funded solid wastes demonstration pro- jects, including those related to sanitary landfills, is available from the Solid Wastes Program. REFERENCES 1. Committee on Sanitary Landfill Prac- tice of the Sanitary Engineering Di- vision. Sanitary landfill. ASCE-- Manuals of Engineering Practice No. 39. New York, American So- ciety of Civil Engineers, 1959. 61 p. 2. Committee on Refuse Disposal, Amer- ican Public Works Association. Municipal refuse disposal. Chica- go, Public Administration Service, 1966. p. 95. 3. Committee on Sanitary Engineering Research. A survey of sanitary landfil] practices; thirtieth prog- ress report. Paper 2874. In Pro- ceedings, The American Society of Civil Engineers, July 1961. ------- BIBLIOGRAPHY American Public Works Association, Committee on Refuse Disposal. Sanitary landfills. Chapt. 4. In Municipal refuse disposal. Chicago, Public Administra- tion Service, 1966. p. 89-139. ASCE Committee on Sanitary Engineer- ing Research. Refuse volume reduction in a sanitary landfill; 26th progress re- port. Proceedings, American Society of Civil Engineers, Journal of the Sanitary Engineering Division, 85(SA6):37-50, Nov. 1959. Discussion. D. T. Mitchell. 86 (SA3):l65-l66, May I960. Reply. Solid Waste Engineering Section of the Sanitary Engineering Research Committee. 86 (SA6):85, Nov. I960. ASCE Committee on Sanitary Engineer- ing Research, Solid Waste Engineering Section. SED research report no. 21; sanitary landfill tests investigating refuse volume reduction and other phenomena. Paper 1853. Proceedings, American So- ciety of Civil Engineers, Journal of the Sanitary Engineering Division, 84(SA6): T853. 1-1853.3, Nov. 1958. ASCE Committee on Sanitary Engineering Research. Survey of sanitary landfill practices; thirtieth progress report. Proceedings, American Society of Civil Engineers, Journal of the Sanitary Engi- neering Division, 87(SA4): 65-84, July 1961. Discussion. J. L. Vincenz, D. T. Mitchell, T. E. Winkler, and J. R. Snell. 88(SAl):43-49, Jan. 1962. Reply. Com- mittee on Sanitary Engineering Research. 88(SA3):169-171, May 1962. ASCE Committee on Sanitary Landfill Practice of the Sanitary Engineering Di- vision. Sanitary landfill. ASCE--Man- uals of Engineering Practice No. 39. New York, American Society of Civil Engi- neers, 1959. 61 p. Anderegg, R. A. Sanitary landfill proves financially best. American City, 73(7): 159, 161, July 19 5lT Andersen, J. R., and J. N. Dornbush. Influence of sanitary landfill on ground water quality. Journal American Water Works Association, 59(4):457-470, Apr. 1967. Bailey, C. A. , Jr. Public approves san- itary fill in a residential zone "A"; when the potential improvement to the land is apparent. American City, 67(11): 126-127, Nov. 1952. Basgall, V. A. , W. F. Johnson, and C. F. Schwalm. Sanitary fill series--trench type: Civic pride; One man, one machine; Do you realize that a city's garbage can turn wasteland into a beautiful playground? American City, 69(2): 102-105, Feb. 1954. Bevan, R. E. Notes on the science and practice of controlled tipping of refuse. London, The Institute of Public Cleansing, 1967. 216 p. Bjornson, B. F. , and M. D. Bogue. Keeping a sanitary landfill sanitary. Pub- lic Works, 92(9): 112-114, Sept. 196"T 23 ------- 24 Black, R. J. , and A. M. Barnes. Effect of earth cover on housefly emergence. Public Works , 87(3): 109-111, Mar. 1956. Black, R. J. , and A. M. Barnes. Effect of earth cover on fly emergence from sanitary landfills. Public Works, 89(2): 91-94, Feb. 1958. Black, R. J. Suggested landfill standards and methods. Refuse Removal Journal, 4(10):10, 20-21, 25-29, Oct. 1961. Black, R. J. , J. B. Wheeler, and W. G. Henderson. Refuse collection and dis- posal; an annotated bibliography; 1962- 1963. Public Health Service Publication No. 91. Washington, U.S. Government Printing Office, 1966. 134p. (Suppl. F). Booth, E. , and E. Carlson. Rubber tires work well on sanitary landfills. Ameri- can City, 81(7):98-99, July 1966. Booth, E. J. , and D. Keagy. How to op- erate sanitary landfill in really cold weather. Public Works, 83(5):64-65, 102-103, May 1952. California State Water Pollution Control Board. Report on the investigation of leaching of a sanitary landfill. Publica- tion No. 10. Sacramento, California State Water Pollution Control Board, 1954. 96 p. California State Water Pollution Control Board. Effects of refuse dumps on ground water quality. Publication No. 24. Sac- ramento, California State Water Pollution Control Board, 1961. 107 p. Do you need a sanitary landfill? Public Health Service Publication No. 1012. Washington, U. S. Government Printing Office, 1963. 8 p. Eliassen, R. Load-bearing character- istics of landfill. Engineering News Rec- ord, 129(11):103-105, Sept. 1942. Eliassen, R. , F. N. O'Hara, and. E. C. Monahan. Sanitary landfill gas control; how Arlington, Mass. , discovered and corrected a danger spot in its sanitary landfill. American City. 72(12): 1 15- 1 17, Dec. 1957~ Fleming, R. R. Solid-waste disposal; Part I- -sanitary landfills. American City, 81(1):101-104, Jan. 1966. Fundamental of s anitary landfill operation. Public Works, 95(12):88-89, Dec. 1964. Goodrow, T. E. Sanitary landfill be- comes major league training field. Pub- lic Works, 96(8):124-126, Aug. 196?! Hennigan, R. D. Sanitary landfill equip- ment requirements. In American Public Works Association Yearbook. Chicago, American Public Works Association, 1963. p. 327-332. How to use your completed landfills. American J3ity, 80(8):91-94, Aug. 1965. Johnson, W. H. , and B. F. Bjornson. Sanitary landfill; training guide. Atlanta, Communicable Disease Center, Public Health Service, U.S. Dept. of Health, Education, and Welfare, 1962. 20 p. Klassen, C. W. Locating, designing and operating sanitary landfills. Public Works, 81(ll):42-43, Nov. 1950. Klassen, C. W. Sanitary fill standards. American City, 66(2): 104- 105, Feb. 1951. Merz, R. C. , and R. Stone. Landfill settlement rates. Public Works, 93(9): 103-106, 210, 212, Sept. 1962. ------- 25 Merz, R. C. , and R. Stone. Factors controlling utilization of sanitary landfill site; final report to Department of Health, Education, and Welfare, May 1, I960 - May 31, 1963. Los Angeles, University of Southern California, 1963. 126 p. Merz, R. C. , and R. Stone. Gas pro- duction in a sanitary landfill. Public Works, 95(2):84-87, 174-175, Feb. 1964. Michaels, A. Municipal solid-waste dis- posal. Part II. The sanitary landfill. American City, 77(3);92-94, Mar. 1962. Moehr, L. H. Park and playground built with sanitary fill. American City, 65(4): 102-103, Apr. 195(T Municipal refuse collection and disposal-- evaluation, regulations, methods, proce- dures; a guide for municipal officials. Office for Local Government, State of New York, 1964. 69 p. Nickerson, H. D. Selection of sanitary landfill sites. Sanitalk, 9(2):9-12, Spring 1961. Operation of sanitary landfills. Public Works, 89(9):115-117, 206-209, Sept. 1958. Partin, J. L. Sanitary fill practice in Los Angeles County. Proceedings, American Society of Civil Engineers, Sanitary En- gineering Division, 81(Separate 688): 688.1-688. 6, May 1955. Refuse collection and disposal--repairs and utilities; wartime technical manual. TM5-634. War Department, Oct. 1945. Rogus, C. A. Use of completed sanitary landfill sites. Public Works, 91(1): 139- 140, Jan. 1960. Sanitary fill--how it operates. Part I. What it is, and data on how it functions in cities with commendable fills. American City, 76(2):84-87, Feb. 1961. Sanitary fill--how it operates. Part II. Basic principles, economics, equipment andfutureuse of reclaimed land. Amer- ican City, 76(3):98-103, Mar. 196T] Sanitary fill--how it operates. Part III. Basic methods and operating techniques. American City. 76(4):84-88, Apr. 1961. Spencer, C. C. Recommended wartime refuse disposal practice; with particular reference to sanitary landfill method of disposal for mixed refuse. Public Health Reports Suppl. 173. Washington, U.S. Government Printing Office, 1943. 19 p. Reprinted as, Refuse disposal by sanitary landfill method. Water and Sewage, 82(8): 17-21, 48-50, Aug. 1944. 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D. tries cold-weather operation of sani- tary landfill. American City, 67(9): 110- 111, Sept. 1952. Williams, E. R. , G. F. Mallison, and P. P. Maier. Light equipment for small town sanitary landfill operations. Public Works, 89(2):89-91, Feb. 1958. Winkler, T. E. Compaction, settlement of sanitary landfills. Refuse Removal Journal, l(12):8-9, 24-25, Dec. 1958. U.S. GOVERNMENT PRINTING OFFICE • 1969 O - 338-532 ------- U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service NATIONAL CENTER FOR URBAN AND INDUSTRIAL HEALTH solid wastes program regional offices REGION I John Fitzgerald Kennedy Federal Building Boston, Massachusetts 02203 (telephone: 617-223-6687) REGION II 837H Federal Office Building 26 Federal Plaza New York, New York 10007 (telephone: 212-264-2523) REGION III 220 Seventh Street, NE Charlottesville, Virginia 22901 (telephone: 703-296-1 445) REGION IV 404 Peachtree-Seventh Building 50 Seventh Street, NE Atlanta, Georgia 30323 (telephone: 404-526-3454) REGION V 71 2 New Post Office Building 433 West Van Buren Street Chicago, Illinois 60607 (telephone: 312-353-5465) REGION VI Federal Office Building 601 East 12th Street Kansas City, Missouri 641 06 (telephone: 816-374-3307) REGION VII 1114 Commerce Street Dallas, Texas 75202 (telephone: 214-749-2007) REGION VIII 9017 Federal Office Building 19th and Stout Streets Denver, Colorado 80202 (telephone: 303-297-4456) REGION IX 254 Federal Office Building 50 Fulton Street San Francisco, California 94102 (telephone: 41 5-556-8480) ------- U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Public Health Service Publication No. 1792 ------- |