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Organic Gardeners Composting

Have you always wanted to grow your own vegetables but didn't know what to do? Here are the best tips on how to become a true and envied organic gardner.

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The Keys to a Great Compost

This informative eBook demonstrates the best ways to compost in order to improve your garden, make your vegetables and fruits taste better, and help save the soil and the environment. Over 20% of landfills are simply kitchen waste that could easily be recycled Why waste what you already produce? You have an easy source of organic health for your own garden at home, without having to spend large amounts of money in order to make really healthy soil. With today's composting technology, you can compost as much as suits your needs! If that is a little compost for a small home garden or a large plot that you grow food for your family or business, composting will be an easy and cheap way to improve the quality of your soil and thus your vegetables as well! This guide shows you every method of composting; from free methods you can do with no extra money all the way to elaborate by easy to set up composting rigs. Improve the environment, and get better tasting food!

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Author: Duane Palmer
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Cocomposting Retrieved Organics With Sludge

The principles of composting and a description of the process technology are presented in Section 7.43 for sludge composting. While the fundamentals of sludge composting are applicable to MSW composting, several significant differences exist. The major difference involves preprocessing when MSW is composted. As shown in Figure 10.14.1, receiving, the removal of recoverable material, size reduction, and the adjustment of waste properties (e.g., the C N ratio and the addition of moisture and nutrients) are essential steps in preparing MSW for composting. Obviously, different preprocessing strategies are needed for source-separated organic MSW and yard waste. Also, the degree of preprocessing depends on the type of composting process used and the specifications for the final compost product (Tchobanoglous, Theissen, and Vigil 1993). MSW composting employs the same techniques as sludge composting windrow, aerated static pile, and in-vessel systems. Tchobanoglous, Theissen, and Vigil (1993)

Aerobic Composting in MSW Management

The organic fraction of MSW includes food waste, paper, cardboard, plastics, textiles, rubber, leather, and yard waste. Organic material makes up about half of the solid waste stream (Henry 1991) (see Section 10.5). Almost all organic components can be biologically converted although the rate at which these components degrade varies. Composting is the biological transformation of the organic fraction of MSW to reduce the volume and weight of the material and produce compost, a humus-like material that can be used as a soil conditioner (Tchobanoglous, Theissen, and Vigil 1993). Composting is gaining favor for MSW management (Goldstein and Steuteville 1992). It diverts organic matter from landfills, reduces some of the risks associated with landfilling and incineration, and produces a valuable byproduct (compost). At the present time, twenty-one MSW composting plants are operating in the United States (Goldstein and Steuteville 1992). Most of these plants compost a mixed MSW waste...

Table 7551 Design Considerations For Aerobic Sludge Composting Processes

Both untreated and digested sludge can be composted successfully. Untreated sludge has a greater potential for odors, particularly for windrow systems. Untreated sludge has more energy available, degrades more readily, and has a higher oxygen demand. Amendment and bulking agent characteristics, such as moisture content, particle size, and available carbon, affect the process and quality of the product. Bulking agents should be readily available. Wood chips, sawdust, recycled compost, and straw can be used. The volatile solids of the composting mix should be greater than 50 . Air with at least 50 oxygen remaining should reach all parts of the composting material for optimum results, especially in mechanical systems. The moisture content of the composting mixture should be not greater than 60 for static pile and windrow composting and not greater than 65 for in-vessel composting. The pH of the composting mixture should generally be in the range of 6 to 9. The optimum temperature for...

Compost Filters

W& H Pacific conceived the idea of utilizing yard debris compost as a treatment and filtration medium for storm-water runoff. This medium removes organic and inorganic pollutants through adsorption, filtration, and biological processes (ion exchange and bioremediation). The Compost Storm Water Treatment System (CSF ) has been constructed at eight different sites throughout Oregon. Six of the eight systems are enclosed facilities, located below grade, while the remaining two are open channel systems retrofitted into existing swales. The technology is being tested and field modified. The filtering capacity of the medium removes sediments from the runoff. Ion exchange and adsorption removes oils and greases, heavy metals, and non-dissolved nutrients. Following adsorption, organic material is further broken down into carbon dioxide and water by microbial action within the compost. Treated stormwater then passes through a 6 in to 8 in gravel layer underneath the filtering media, and is...

Composting

Composting is the aerobic, theromophilic, biological decomposition of organic material under controlled conditions. It is essentially the same process that is responsible for the decay of organic matter in nature except that it occurs under controlled conditions. As a consequence, new practices are being encouraged that include the treatment of organic waste with resource recovery. Composting is one of these practices (Kuchenrither et al. 1987). Composting is a method of solid waste treatment in which the organic component of the solid waste stream is biologically decomposed under controlled aerobic conditions to a state in which it can be safely handled, stored, and applied to the land without adversely affecting the environment. It is a controlled, or engineered, biological system. Composting can provide pathogen kill, volume reduction and stabilization, and resource recovery. Properly composed waste is aesthetically acceptable, essentially free of human pathogens, and easy to...

1253 Composting

Composting of municipal solid waste in the United States is still in its infancy. According to BioCyle, 18 such facilities are currently in operation, and two are under construction.158 Some facilities process a mixed waste stream and others process source-separated organics (that is, the generators of the waste separate the compostable organics from the noncompostable wastes). Generally, the source-separated organics stream contains paper and food waste, and does not include any plastics. Some institutional composting of source-separated organics, such as of waste from fast-food restaurants, has included biodegradable plastics used for food containers and cutlery. The mixed-waste composting facilities do include plastics among the materials collected. The EPA counted 14 such mixed waste composting facilities in 1996, handling a total of about 900 tons day.2 In such systems, the waste is generally processed to remove large items, ferrous metals, and sometimes other components before...

Nonload Related Design Considerations

Cyclic or repeated motion caused by seismic forces or earthquakes, vibrating machinery, and other disturbances such as vehicular traffic, blasting and pile driving may cause pore pressures to increase in foundation soil. As a result, bearing capacity will be reduced from the decreased soil strength. The foundation soil can liquify when pore pressures equal or exceed the soil confining stress reducing effective stress to zero and causes gross differential settlement of structures and loss of bearing capacity. Structures supported by shallow foundations can tilt and exhibit large differential movement and structural damage. Deep foundations lose lateral support as a result of liquefaction and horizontal shear forces lead to buckling and failure. The potential for soil liquefaction and structural damage may be reduced by various soil improvement methods. (2) Potential Collapse. The potential for collapse should be determined from results of a...

Summary and Conclusions

Composting is a cost effective and environmentally sound alternative for the stabilization and ultimate disposal of wastewater sludge. It produces compost a stable, humuslike material which is a soil conditioner. Thus, the process can achieve waste treatment with resource recovery and represents a beneficial use of sludge. Recent advances have been made in the basic fundamental science associated with composting along with the technology used for the process. These advances have increased the use of the process for wastewater sludge management. While the composting process is simple in concept, it must be regarded as an engineered unit process. As such, it must be based on sound scientific principles, designed with good engineering, and operated with care by well-trained and motivated operators. With these practices, wastewater treatment facilities can produce a safe compost of consistently good quality in an environmentally sound manner.

Special Considerations

With restrictions on the disposal of sludge, beneficial use of biosolids has become a significant trend. Composting is the leading beneficial reuse technology in terms of manufacturing a product for application to the land. Of course, the success of composting depends on marketing the final compost product. In other words, a use must exist for the compost generated from wastewater sludge. In addition, the public must accept the composting process. Donovan (1992) notes that the most difficult challenge municipalities face in implementing sludge plans is facility siting. The general public is apprehensive concerning any waste handling facility, and specific concerns about odor, health, traffic, and land values have slowed or stopped many projects. Composting is basically a simple process it is quite robust and therefore a forgiving process. It can be managed in many cases (such as the backyard compost pile) with little or no technical knowledge. However, as composting applications...

Implications for Recovery of Useful Materials

Almost all solid waste materials can be recycled in some way if people are willing to devote enough time and money to the recycling effort. Because time and money are always limited, distinctions must be drawn between materials that are more and less difficult to recycle. Table 10.5.1 shows the compostable, combustible, and recyclable fractions of MSW. The materials listed as recyclable are those for which large-scale markets exist if the local recycling industry is well developed. The list of recyclable materials is different in different areas. Approximately 75 of the MSW discarded in the United States is compostable or recyclable. No solid waste district of substantial size in the United States has documented a 75 rate of MSW recovery and reuse, however. Reasons for this include the following contamination during use. A significant fraction of recyclable material cannot be recovered from the consumer. A portion of both recyclable and compostable material is lost during processing...

Stability And Product Quality

In composting operations, the objective is decomposition rather than complete stabilization. The degree of decomposition, however, is not an absolute state since it depends on the final product use. In some cases, the degree is one where the material does not cause nuisances when stored even if it is wetted. If the final product is used on a plant system, the compost should not be phytotoxic. Currently, many parameters can be used for composting process control and final product quality including the final drop in temperature degree of self-heating capacity amount of decomposable and resistant organic material rise in redox potential oxygen uptake and carbon dioxide evolution starch test color, odor, appearance, and texture pathogen and indicator organisms and inhibition of germination of cress seeds (Finstein, Miller, and Strom 1986 Inbar et al. 1990). This list covers many possibilities, but which are best for measuring the completion of composting is unclear. The optimal parameter...

Process Description

Numerous types of composting systems exist, but for the most part, composting systems can be divided into three categories windrow, static pile, and in-vessel. Windrow systems are composed of long, narrow rows of sludge mixed with a bulking agent. The rows are typically trapezoidal in shape, 1 to 2 m high and 2 to 4.5 m wide at the base. The rows are usually uncovered but can be protected by simple roofs. The sludge mixture is aerated by convec-tive air movement and diffusion. Wastewater treatment facilities periodically turn the rows using mechanical means to expose the sludge to ambient oxygen, dissipate heat, and refluff the rows to maintain good free air space. Windrows can also be aerated by induced aeration (Hay and Kuchenrither 1990). Windrows are space-intensive but mechanically simple. In-vessel composting takes place in either partially or completely enclosed containers. A variety of schematics use various forced aeration and mechanical turning technologies (Tchobanoglous...

Odors And Odor Control

Odor control has become a major concern in the successful operation of any composting facility. Indeed, some operating facilities have been closed due to odor problems (Libby 1991). Numerous papers have been published identifying the causes of odors and management strategies to control odors (Hentz et al. 1992 Miller 1993 Goldstein 1993 Van Durme, McNamara, and McGinley 1992). Many potential sources of odors exist at composting facilities. While the process air coming off a compost pile is most odorous, environmental engineers must evaluate all potential sources of odors. Therefore, a proper inventory of the potential sources of odors is necessary including liquid sludge and dewatered sludge facilities. Haug (1990) states that odors are part of the composting process and cannot be eliminated, but they can be managed. Finstein et al. (1986 1993) point out that controlling the composting process is crucial in minimizing odor production. This process control includes good aeration and...

Sewage Sludge Incineration

Sewage sludge, the stabilized and digested solid waste product of the wastewater treatment process, can be disposed of by landfilling, incineration, composting, or ocean dumping. Nature returns organic material to the soil as fertilizer. Organic material becomes waste when it is not returned to the soil but instead is burned, buried, or dumped in the ocean. These unhealthy practices began when chemical fertilizers took the market away from sludge-based compost and when industrial waste began to contaminate sewage sludge with toxic metals (lead and cadmium), making it unusable for agricultural purposes. Until recently, the bulk of the sewage sludge generated by metropolitan areas has been either landfilled or dumped in the ocean. These options are gradually disappearing and as a result municipalities will have to make some hard decisions. (See Sections 7.31 to 7.56).

Onsite Wastewater Treatment

The original on-site system, of course, is the pit privy, glorified in song and fable.1 The privy, still used in camps and temporary residences and in many less industrialized countries, consists of a pit about 2 m (6 ft) deep into which human excrement is deposited. When a pit fills up, it is covered and a new one is dug. The composting toilet, which accepts both human excrement and food waste, and produces a useful compost, is a logical extension of the pit privy. In a dwelling with a composting toilet, wastewater from other sources, like washing, is discharged separately.

1251 Definitions and tests

Another point of confusion has been the reasonable time part of the definition. As is also true for photodegradation, the time required for biodegradation is a function of exposure conditions (as well as a function of the extent of degradation defined as the end point). Time to reach the defined end point after disposal can be markedly different if the object degrades in sewage sludge, in a compost pile, or in a landfill, even under the same climatic conditions. To this variation, then, must be added differences in ambient temperatures, rainfall, etc. will completely break down and return to nature, i.e., decompose into elements found in nature within a reasonably short period of time after customary disposal. Unqualified claims about compostability can be made only if all materials in the product or package will break down into, or otherwise become part of, usable compost (e.g., soil-conditioning material, mulch) in a safe and timely manner in an appropriate composting program or...

Raw Material Selection And Mixture

Wastewater treatment facilities add amendments to sludge to adjust the moisture and other characteristics (such as nutrient level) to improve composting. Bulking agents are added for structural support. The goal is to create a mixture of sludge and bulking agent and amendment with the proper characteristics to support aerobic digestion. The choice of material depends on the characteristics of the sludge, in particular the moisture content (which depends on the degree and type of dewatering process) and the nitrogen content of the sludge. The proper mixture has an appropriate C N balance, proper porosity (to ensure aerobic conditions), and proper moisture content. Haug (1993) points out that the amount of free air space in the mixture is more crucial than the porosity, which is the amount of space not occupied by solids or water. FIG. 7.55.1 Composting process flow diagram. FIG. 7.55.1 Composting process flow diagram. FIG. 7.55.2 Composting process. FIG. 7.55.2 Composting process.

Processing And Resource Recovery

Recovery of Biological Conversion Products Biological conversion products that can be derived from solid wastes include compost, methane, various proteins and alcohols, and a variety of other intermediate organic compounds. The principal processes that have been used are reported in Table 25-64. Composting and anaerobic digestion, the two most highly developed processes, are considered further. The recovery of gas from landfills is discussed in the portion of this section dealing with ultimate disposal.

Component Composition of MSW

Table 10.3.1 lists the representative component composition for MSW disposed in the United States and adjacent portions of Canada and shows ranges for individual components. Materials diverted from the waste stream for recycling or composting are not included. The table is based on the results of twenty-two field studies in eleven states plus the Canadian province of British Columbia. The ranges shown in the table are annual values for county-sized areas. Seasonal values may be outside these ranges, especially in individual municipalities.

Gaseous Emission Control Biofiltration

The biological treatment of VOCs and other pollutants has received increasing attention in recent years. Biofiltration involves the removal and oxidation of organic compounds from contaminated air by beds of compost, peat, or soil. This treatment often offers an inexpensive alternative to conventional air treatment technologies such as carbon adsorption and incineration.

Purposes of Solid Waste Characterization

The potential for recycling or composting portions of the waste stream. The purposes of a waste characterization program determine the design of it. If all waste is to be landfilled, the characterization program should focus on the quantity of waste, its density, and its potential for compaction. The composition of the waste and its chemical characteristics are relatively unimportant. If all waste is to be incinerated, the critical parameters are quantity, heat value, and the percentage of combustible material in the waste. If recycling and composting are planned or underway, a composition study can identify the materials targeted for recovery, estimate their abundance in the waste, and monitor compliance with source separation requirements.

Fixed Film Biotreatment Systems

Most biological air treatment technologies are fixed-film systems that rely on the growth of a biofilm layer on an inert organic support such as compost or peat (biofilters) or on an inorganic support such as ceramic or plastic (biotrickling filters). For both systems, solid particles must be removed from waste gases before the gases enter the system particulates plug the pores. Both systems are best suited for treating vapor streams containing one or two major compounds. When properly designed, biofilters are well suited for treating streams that vary in concentration from minute to minute.

Implications For Solid Waste Management

This section addresses several aspects of the relationship between the characteristics of solid waste and the methods used to manage it. Implications for waste reduction, recycling, composting, incineration, and landfilling are included, as well as general implications for solid waste management as a whole.

Flash Drying Versus Other Processes

Composting sewage sludge is an innovation because no commercial installations exist in which sewage solids are composted alone. The process has potential both ecologically and economically but requires using shredded municipal refuse. When sludge is composted alone, without shredded refuse, successful treatment requires recycling the drier, already composted, sewage solids with the raw, wetter, dewatered solids, such as occurs in the second step of the flash-drying method. This recycling produces a drier, more porous sludge, which is necessary for good composting.

1263 Proteinbased plastics

Aging material, in film form and as a paper coating. Zein films and zein-coated paper were shown to be heat-sealable and compostable, as well as suitable for animal feed. The investigators also claimed that zein-coated paper is recyclable with ordinary paper. The material could also be modified with plasticizer.222

1281Polyvinyl alcohol

One difficulty in using this polymer is that it is generally not melt processable, since its decomposition temperature is lower than its melting point. Films are typically prepared by a solution casting process from a water solution. Plasticizers are incorporated in some resins. The films are readily biodegraded in wastewater streams or in compost. It is printable using either water-based or solvent-based inks. The materials are resistant to most organic liquids, including solvents, and to mineral oils. Film can be used to package products having low water contents but not high ones.252

535 The waste hierarchy

The government's strategy for waste management promotes the 'waste hierarchy' as a guiding principle in the development of a more sustainable waste management system. Following the hierarchy is also a cost-effective and environmentally responsible approach to managing waste. The hierarchy ranks methods of waste management, defining elimination and reduction as the most desirable options followed by reuse, then recovery (through recycling, composting or energy recovery) and finally the least desirable option, disposal. Examples are returnable bottles and reusable transit packaging. Involves finding beneficial uses for waste such as recovering energy by burning it recycling it to produce a useable product or composting to create products such as soil conditioners and growing media for plants. The destruction, detoxification or neutralisation of wastes into less harmful substances.

Material Recovery Plant

The organics fraction, left from the plant feed after the removal of metals, plastic film, and paper, is essentially a heavy fraction of small-sized particles containing organics, glass, ceramics, sand, ashes, hard plastics, and small pieces of wood. This fraction is placed into an aerobic digester and broken down into raw compost. After the removal of glass, ceramics, and other inorganic rejects, the raw compost is subcontracted for further processing. This processing splits the organic fraction into a feed fraction (a high-quality compost fraction) and a residue, which is usually landfilled.

Separation at the Source

The more finely household waste is separated, the greater its contribution to recycling. Figure 10.6.1 shows an approach where household waste is separated into four containers. Container 1 would receive all organic or putrescible materials, including food-soiled paper and disposable diapers and excluding toxic substances and glass or plastic items. The contents of this container can be taken to a composting plant that also receives yard wastes and possibly sewage sludge and produces soil additives. Separate collections are required for trash items that are not generated on a daily basis, such as yard waste, brush

1651 Municipal Waste Incineration

Clarke 52 has written a good primer on MSW incineration. There has been a decided shift in preference away from landfilling and incineration with no energy recovery towards waste prevention, recycling, composting, and waste-to-energy (WTE) plants utilizing incineration for waste management. An example of a MSW incineration process is shown in Fig. 16.13. A photograph of an actual municipal waste incineration plant is shown in Fig. 16.14. Some of the important design factors for municipal incineration with energy recovery include

Review and Use of Laboratory Results

Dry-basis results for the paper, yard waste, plastics, wood, and disposable diapers categories should be close to those shown in Tables 10.3.4 and 10.3.5. Greater variability must be accepted in individual results for food waste, textiles rubber leather, fines, and other combustibles because of the chemical variety of these categories. Among the paper categories, only those with high proportions of glossy paper, such as magazines and advertising mail, should have ash values significantly greater than 10 . Nitrogen should be below 1 for all categories except grass clippings, other yard waste, food waste, textiles rubber leather, fines, and other organics (see Table 10.3.4).

Basic Characterization Methods

Obtaining complete production data for every item discarded as solid waste is difficult. Although data on food sales are available, food sales bear little relation to the generation of food waste. Not only is most food not discarded, but significant quantities of water are added to or removed from many food items between purchase and discard. These factors vary from one area to another based on local food preferences and eating patterns. Material flows methodology cannot measure the generation of yard waste. Material flows methodology does not account for the addition of nonmanufactured materials to solid waste prior to discard, including water, soil, dust, pet droppings, and the contents of used disposable diapers. Some of the material categories used in material flows studies do not match the categories of materials targeted for recycling. For example, advertising inserts in newspapers are typically recycled with the newsprint, but in material flows studies the inserts are part of a...

Grease Traps And Grease Interceptors

Where the wastewater contains large amounts of greasy kitchen waste, grease traps should be used. Their minimum capacity is 3.0 gal (11.5 l) per capita and should be no less than 30 gal (0.115 m3) per unit (see Figure 7.16.1). The influent line should terminate at least 6in (15 cm) below the water line, and the effluent pipe should take off near the bottom of the tank.

832Sulfur in the Incoming Raw Materials

In the glass manufacturing process, SOx emissions may result from sodium sulfate (salt cake) used to condition the glass in the manufacture of soda-lime glass and wool fiberglass. Sulfur is present in limestone used in the production of lime and cement. In the production of ethylene from a liquid feed, the incoming raw materials may consist of gas oils, and heavier fractions often contain sulfur that can be removed by hydrodesulfurization. Some of the sulfur for the SOx emissions from waste-incineration processes comes from the incoming waste materials usually in the form of sulfates or sulfides from, for example, paper, food waste, garden waste, and rubber. Sewer sludge incinerated in waste combustors also usually contains some sulfur.

916 Foundations in liquefiable ground

When using piles in liquefiable ground, the piles should be designed for the conditions induced by liquefaction, as the loss of soil support in the liquefied layer may cause large forces in the piles (Nishizawa et al., 1984). Concrete piles should be detailed for strength and ductility as for columns (Section 10.3.3). However, sole reliance on piles should be practised with caution, because of the difficulty of determining the location and thickness of potential liquefaction layers. In many cases, it will be appropriate to combine piling with a degree of soil improvement to reduce the probability of liquefaction occurring. A range if issues related to the design of piles in liquefiable ground are discussed by Berrill and Yasuda (2002). Soil improvement Densification increases the strength and stiffness of the soil, and reduces the tendency to generate excess porewater pressures under cyclic loading. It is thus one of the most effective and commonly used soil...

20492preliminary Design

When a justification study has determined that a retaining wall is required, generally the wall will be a cast-in-place reinforced concrete wall or some type of proprietary wall system. Generally, the use of proprietary wall systems should be considered when the wall quantity for the project exceeds 5000 ft2 450 m2 . If a proprietary wall is justified, the preliminary design submission shall include footing elevations, allowable bearing pressures, global stability analysis, settlement calculations and any construction constraints, such as soil improvement methods, that may be required. Additionally, the Design Agency shall state in the preliminary design submission the proposed method of plan development (Section 204.9.2.1 or Section 204.9.2.2). When a cast-in-place wall is justified, the design agency will be responsible for providing the complete wall design in the detail plans.

1851 Soil Remediation Procedures

Because much of Japan is covered with either weak clay or saturated, loosely consolidated material, the development of soil remediation procedures has flourished in that country. After the 1994 Kobe Earthquake researchers did a careful study of soil-remediation sites and found that these locations performed much better than the surrounding area 10 . The following are a few examples of soil improvement methods commonly used in Japan.

1272 Polycaprolactone

Polycaprolactone resins under the brand name Tone. These polymers are compostable but not water soluble.216 A primary application is for compostable bags for yard waste or other organics collection. They can be utilized as homopolymers, copolymers, or in blends. For example, R. Narayan, of Michigan State University, has investigated Envar, formed from polycaprolactone and thermoplastic starch, as a substrate for biodegradable compost bags.215 Other companies using starch polycaprolactone blends are discussed in Sec. 12.5.2.

1273 Other polyesters

DuPont has created a family of synthetic polyesters which are degraded by a combination of hydrolysis and microbial action. These materials, sold under the Biomax name, are similar to polyethylene terephthalate, but incorporate as many as three different proprietary aliphatic monomers into the structure. The monomers create weak spots which are susceptible to hydrolysis. The much smaller molecules which result are biodegradable. DuPont claims that in composting operations the materials are totally harmless and cannot be undetected by the unaided eye after about 8 weeks. The resins can be manufactured with existing equipment and existing bulk monomers, so they are only marginally more expensive than PET. Applications include household wipes, yard waste bags, components in disposable diapers, disposable eating utensils, geotextiles, agricultural films, plant pots, coated paper products, adhesives, and more. Biomax can be thermoformed, blow molded, and injection molded. Properties can be...

Component Composition of Bulky Waste

The composition of MSW does not change dramatically from season to season. Even the most variable component, yard waste, may be consistent in areas with mild climates. In areas with cold winters, generation of yard waste generally peaks in the late spring, declines gradually through the summer and fall, and is lowest in January and February. A surge in yard waste can occur in mid to late fall in areas where a large proportion of tree leaves enter the solid waste stream and are not diverted for composting or mulching.

125 Overview of Plastics Degradation

In the mid-1980s, when concerns about solid waste disposal were increasing rapidly, there was again a flurry of interest in biodegradation, stemming from a perception that disposal problems could be alleviated substantially if we stopped filling up our landfills with nonbiodegradable plastics and instead switched to biodegradable materials. As information increased about both the composition and the behavior of solid waste in landfills, it became clear that this was a misperception. First, the majority of material in landfills was, in fact, biodegradable, consisting of paper, food waste, and yard waste. Second, conditions in modern landfills, designed to keep materials dry to reduce problems with groundwater contamination, were not conducive to rapid biodegradation. Pictures of grass clippings, vegetables, and hot dogs, still recognizable after 10 to 20 years in a landfill, reinforced this reality, as did the statement by landfill researchers such as William Rathje of the University...

Fluctuations in Solid Waste Quantities

The generation of solid waste is usually greater in warm weather than in cold weather. Figure 10.3.1 shows two month-to-month patterns of MSW generation. The less variable pattern is a composite of data from eight locations with cold or moderately cold winters (Camp Dresser & McKee Inc. 1992, 1991 Child, Pollette, and Flosdorf 1986 Cosulich Associates 1988 HDR Engineering, Inc. 1989 Killam Associates 1990 North Hempstead 1986 Oyster Bay 1987). Waste generation is relatively low in the winter but rises with temperature in the spring. The surge of waste generation in the spring is caused both by increased human activity, including spring cleaning, and renewed plant growth and associated yard waste. Waste generation typically declines somewhat after June but remains above average until mid to late fall. In contrast, Figure 10.3.1 also shows the pattern of waste generation in Cape May County, New Jersey, a summer resort area (Camp Dresser & McKee Inc. 1991). The annual influx of...

1252 Effects of environmentexposure conditions

In contrast to landfills, compost operations, which will be addressed further in Sec. 12.5.3, are designed to ensure rapid biodegradation of susceptible materials. In composting, a water and oxygen-rich environment is maintained, along with a suitable inoculation of microorganisms to start the decay process. The time required for production of usable compost varies, but is most often less than a year. The composting operation can use open piles or windrows or closed containers. It can run on a very large scale as either a municipal or privately owned operation, or it can be a small compost pile in someone's backyard. It can be an open-air facility, contained inside a building, or operate in closed containers. It can contain yard waste only, source-separated organics, or mixed municipal solid waste. Composting of yard waste has grown rapidly in the United States over the last decade, significantly influenced by legislation in many states which prohibits the landfilling of yard waste....

4Establishment of Vegetation

Soil treatments, such as the use of slow release fertilizer incorporation of soil amendments such as compost into the soil layer and surface mulching, may improve the success rate of introduced vegetation. Consult the WSDOT Horticulturist for recommendations. (Check with the local maintenance office or the local jurisdiction's comprehensive plan for any restrictions such as those in well-head protection areas.)

Separated And Commingled Waste

Yard waste composting includes leaves, grass clippings, bush clippings, and brush. This waste is usually collected separately in special containers. Yard waste composting is increasing especially since some states, as a part of their waste diversion goals, are banning yard waste from landfills (Glenn 1992). The U.S. EPA (1989) Strom and Finstein (1985) and Richard, Dickson, and Rowland (1990) provide detailed descriptions of yard waste composting. Separated MSW refers to the use of mechanical and manual means to separate noncompostable material from compostable material in the MSW stream before composting. The mechanical separation processes involve a series of operations including shredders, magnetic separators, and air classification systems. The sequence is often referred to as front-end processing. Front-end processing prepares the feedstock for efficient composting in terms of homogeneity and particle size. Front-end processing also removes the recyclable components and thus...

Sampling MSW to Estimate Composition

A fundamental question is the time period(s) over which to collect the samples. One-week periods are generally used because most human activity and most refuse collection schedules repeat on a weekly basis. Sampling during a week in each season of the year is preferable. Spring sampling is particularly important because generation of yard waste, the most variable waste category, is generally least in the winter and greatest in the spring.

Afterfilter

Anchoring a dredge. 'e-re-sl 'spsd aerial survey eng A survey utilizing photographic, electronic, or other data obtained from an airborne station. Also known as aerosurvey air survey. 'e-re-sl 'ssr-va aerial tramway mech eng A system for transporting bulk materials that consists of one or more cables supported by steel towers and is capable of carrying a traveling carriage from which loaded buckets can be lowered or raised. Also known as aerial cableway aerial ropeway. 'e-re-sl 'tram.wa aeroballistics mech The study of the interaction of projectiles or high-speed vehicles with the atmosphere. .e-ro-bs'lis-tiks aerobic-anaerobic interface civ eng That point in bacterial action in the body of a sewage sludge or compost heap where both aerobic and anaerobic microorganisms participate, and the decomposition of the material goes no further. e'rob-ik 'an-s.rob-ik 'in-tsr.faas aerobic-anaerobic lagoon civ eng A pond in which the solids from a sewage plant are placed in the lower layer the...

Process Fundamentals

The factors affecting the composting process include oxygen and aeration, nutrients (C N ratio), moisture, porosity, structure, texture and particle size, pH, temperature, and time. These conditions are developed and maintained by process management. The following considerations are important for process management

Aeration

Aeration serves three interdependent functions of composting. Aeration adds stoichiometric oxygen for respiration, removes water vapor, and dissipates heat. Finstein and Hogan (1993) note that heat removal determines the rate of aeration and stress that this removal is important for process control. For proper pathogen removal, the temperature must reach at least 55 C. However, allowing a composting system to reach temperatures of 70 to 80 C is self-limiting, results in poor operation, and leads to the production of unstable compost.

Biofiltration

Biofiltration is an odor control technology that uses a biologically active filter bed to treat odorous chemical compounds. Materials such as soil, leaf compost, peat, and wood chips can be used for the filter bed. The filter bed provides an environment for microorganisms to degrade and ultimately remove the odorous chemical compounds.

Source and Effect

For practical purposes, the term waste includes any material that enters the waste management system. In this chapter, the term waste management system includes organized programs and central facilities established not only for final disposal of waste but also for recycling, reuse, composting, and incineration. Materials enter a waste management system when no one who has the opportunity to retain them wishes to do so.

Bottle Bills

Bottle bills, while having achieved partial success, should be integrated into overall recycling programs, which include office paper and newspaper recycling, cardboard collection from commercial establishments, curbside recycling, establishment of buy-back recycling centers, wood waste and metal recycling, glass and bottle collection from bars and restaurants, and composting programs. Advertising and public education are important elements in the overall recycling strategy. Street signs, door hangers, utility-bill inserts, and phone book, bus, and newspaper advertisements are all useful. The most effective longrange form of public education is to teach school-children the habits of recycling.

531 Introduction

In prehistoric times, waste was mainly composed of ash from fires, wood, bones and vegetable or bodily waste. It was disposed of into the ground, where it would act as a compost and help improve the soil. Waste began to be a problem as the transition came from hunter-gatherer to farmer. The industrial revolution led to a massive population shift from rural areas to the city between 1750 and 1850 in the UK. The growing population living in towns led to an increase in the volume of domestic waste arising, which was matched by the production of industrial waste from new large-scale manufacturing processes. As city populations expanded, space for disposal decreased and societies began to develop waste management systems.

128 Applications

Retained some of these applications and found additional uses in the areas of flexible sheeting, hose piping and small mouldings. In many instances poor formulation gave the material a bad reputation which took some years to eradicate. Over the years many of the additives came under scrutiny concerning their toxicity but the discovery that the monomer had a number of undesirable toxic characteristics caused considerable alarm and revision of manufacturing procedures in the 1970s. More recently there have been worries concerning the use of plasticisers in applications requiring contact with food. In addition there has been concern about the nature of the decomposition products of fire and of composting. Finally, as a long-established material it was first used in a more utilitarian age so that many of its early applications may be considered to be downmarket or, indeed, obsolescent. Not surprisingly, it has been subject to increasing substitution by newer polymers.

Quantities

The advantage of measuring quantity in terms of weight rather than volume is that weight is fairly constant for a given set of discarded objects, whereas volume is highly variable. Waste set out on the curb on a given day in a given neighborhood occupies different volumes on the curb, in the collection truck, on the tipping floor of a transfer station or composting facility, in the storage pit of a combustion facility, or in a landfill. In addition, the same waste can occupy different volumes in different trucks or landfills. Similarly, two identical demolished houses occupy different volumes if one is repeatedly run over with a bulldozer and the other is not. As these examples illustrate, the phrases a cubic yard of MSW and a cubic yard of bulky waste have little meaning by themselves the phrases a ton of MSW and a ton of bulky waste are more meaningful. Franklin Associates, Ltd., regularly estimates the quantity of MSW generated and disposed of in the United States under contract to...

Design Basis

Next, planners must determine what to burn. In keeping with the hierarchy of the Pollution Prevention Act (PPA), a state-of-the-art strategy provides for the maximum amount of source reduction and recycling, including composting, before incineration. Furthermore, materials that are not recyclable and are unsuitable for burning because they are noncombustible, explosive, or contain toxic substances or pollutant precursors, should be separated from the waste to be burned. These activities preserve natural resources, improve incinerator efficiency, and minimize pollutant emissions and ash quantity and toxicity.

Bioavailability

Because microorganisms can metabolize paper, yard waste, food waste, and wood, this waste is classified as biodegradable. Disposable diapers and their contents are also largely biodegradable, as are cotton and wool textiles. Some biodegradable waste materials are more readily metabolized than others. The most readily metabolized materials are those with high nitrogen and moisture content food waste, grass clippings, and other green, pulpy yard wastes. These wastes are putrescible and have high bioavailability. Leaf waste generally has intermediate bioavailability. Wood, cotton and wool, although biodegradable, have relatively low bioavailability and are considered noncompostable within the context of solid waste management.

Heat Value

The as-received heat value is roughly proportional to the percentage of waste that is combustible (i.e., neither moisture nor ash) and to the carbon content of the combustible fraction. The heat values of the plastics categories are highest because of their high carbon content, low ash content, and low-to-moderate moisture content. Paper categories have intermediate heat values because of their intermediate carbon content, moderate moisture content, and low-to-moderate ash content. Yard waste, food waste, and disposable diapers have low heat values because of their high moisture levels.

Plastic

Plastics are strong, waterproof, lightweight, durable, mi-crowavable, and more resilient than glass. For these reasons they have replaced wood, paper, and metallic materials in packaging and other applications. Plastics generate toxic by-products when burned and are nonbiodegradable when landfilled they also take up 30 of landfill space even though their weight percentage is only 7 to 9 . Recent research has found that paper does not degrade in landfills either and because of compaction in the garbage truck and in the landfill, the original volume percentage of 30 in the kitchen waste basket is reduced 12 to 21 in the landfill. In addition, plastics foul the ocean and harm or kill marine mammals. Other problems include the toxic chemicals used in plastics manufacturing, the reliance on nonrenewable petroleum products as their raw material, and the blowing agents used in making polystyrene foam plastics, such as chlorofluorocarbons (CFCs), which cause ozone depletion. CFCs are now...

Refuse Derived Fuels

The waste-to-energy industry (WTE) has been a growing energy source producer (mostly electric generation) for many decades as waste in the United States continues to increase. Waste production has more than doubled over the past four decades. Municipal solid waste (MSW), defined by the EPA to include durable goods, containers and packaging, food wastes, yard wastes, and miscellaneous inorganic waste, has increased from 88 million tons (80 billion kg) in 1960 to current levels of over 200 million tons (181.5 billion kg). Of this total, paper and paperboard account for 39 , yard wastes 31 , plastics 10 , metals 8 , food 7 , and glass 6 . The MSW industry currently has four components recycling, composting, landfilling, and combustion. Refuse can be mass-burned in as-received form or separated, classified, shredded and reclaimed to form a higher energy density, homogeneous product known as refuse-derived fuel (RDF). While beneficial from the perspective of accomplishing two objectives...

Heplon Injection

Potential applications for PLA include cast, blown, and oriented films rigid containers and coating for paperboard. A major application is compost bags. PLA resins were also being used for consumer packaging in Japan, and injection molding applications in both Japan and Europe. Other PLA manufacturers include Mitsui Toatsu and Shimatsu in Japan, Chronopol in Colorado, and Neste Oy in Finland.235,237 Mitsui Toatsu in 1998 introduced an improved generation of its PLA called Lacea. Chronopol had a semicommercial resin trade-named Heplon, with a world scale plant planned within the next few years.238 Duro Bag Manufacturing Company EcoPLA bags consisted of three-layer blown film, with an interior layer of polylactide sandwiched between layers of a proprietary biodegradable aliphatic polyester. The bags were intended to replace paper bags for collection of compostables.239 biodegradable aliphatic polyester that is termed CPLA. The aliphatic polyester is formed from dicarboxylic acid,...

Ultimate Composition

The ultimate composition of MSW on a dry basis reflects the dominance of six types of materials in MSW cellulose, lignins, fats, proteins, hydrocarbon polymers, and inorganic materials. Cellulose is approximately 42.5 carbon, 5.6 hydrogen, and 51.9 oxygen and accounts for the majority of the dry weight of MSW. The cellulose content of paper ranges from approximately 75 for low grades to approximately 90 for high-grade paper. Wood is roughly 50 cellulose, and cellulose is a major ingredient of yard waste, food waste, and disposable diapers. Cotton, the largest ingredient of the textile component of MSW, is approximately 98 cellulose (Masterton, Slowinski, and Stanitski 1981). The inorganic (noncombustible) waste categories contribute most of the ash in MSW. Additional ash is contributed by the inorganic components of combustible materials, including clay in glossy and high-grade paper, dirt in yard waste, bones and shells in food waste, asbestos in vinyl-asbestos floor coverings,...

Degree Of Dryness

The more moisture the sludge contains, the more weight must be removed. If sludge is shredded and stored for use by the citizens, the moisture content at the time of removal is critical. If time permits and ample sand bed capacity exists, the operator can sometimes reduce the moisture content to as low as 50 . If heat drying is used prior to bagging, the sludge should be dried to at least 50 moisture. The same is true if composting is used as a pretreatment to bagging or use by citizens. However, if the sludge is taken to a landfill or farm, it can be removed with a moisture concentration as high as 70 to 80 .

Mechanisms

Biofiltration combines the mechanism of adsorption, the washing effect of water (for scrubbing), and oxidation. Soils and compost have porosity and surface areas similar to those of activated carbon and other synthetic adsorbents. Soil and compost also have a microbial population of more than 1 billion antiomycetes (microorganism resembling bacteria and fungi) per gram (Alexander 1977). These microbes oxidize organic compounds to carbon dioxide and water. The oxidation continuously renews the soil beds adsorption capacity (see Figure 5.22.2). FIG. 5.22.1 Soil bed. A biofilter consists of a bed of soil or compost, beneath which is a network of perforated pipe. Contaminated air flows through the pipe and out the many holes in the sides of the pipe (enlarged detail), thereby being distributed throughout the bed. FIG. 5.22.1 Soil bed. A biofilter consists of a bed of soil or compost, beneath which is a network of perforated pipe. Contaminated air flows through the pipe and out the many...

Pathogens

Wastewater sludge is known to contain pathogens including bacteria, viruses, parasites, and helminths. Epstein and Donovan (1992) note that pathogens can be grouped under three major headings primary pathogens, secondary or opportunistic pathogens, and endotoxins. They further note that the major concerns with pathogens related to composting wastewater sludge are product disinfection, worker health, and public health as impacted by facility location. The U.S. EPA (1979 1993) in the previous 40 CFR Part 257 regulations and the new 40 CFR Part 503 regulations is primarily concerned with product quality and safety of the compost. The possible presence of pathogens is a major concern. The previous regulation for pathogen control was technology based. Under 40 CFR Part 257, minimum standards were issued for processes to significantly reduce pathogens (PSRP). Compost that had been subject to PSRP could be used but was limited to certain restrictions. The previous regulations also defined...

Air Drying

Except for odor control in developed areas or areas with an extremely cold climate, beds need not be covered. Final preparation of the dried sludge for public use, such as shredding, windrow composting, or heat drying, increases its value. When communities use composting in digesting the organic part of municipal refuse, introducing a gravity-thickened, raw sludge is economically competitive. For larger

Conclusion

In the United States, the landfill is the most popular disposal option for MSW. Traditionally, it has been the least-cost disposal option, and it is also a solid waste management necessity because no combination of reduction, recycling, composting, or incineration can currently manage the entire solid waste stream. Developing a new landfill involves site location, landfill design, site preparation, and landfill construction. Locating a new landfill can involve significant public participation. Federal regulations specify many location, design, operation, monitoring, and closure criteria. These regulations reduce the incidence of unacceptable pollution caused by landfills.

Moisture Management

Moisture management is an important part of composting. As stated previously, typically the initial moisture content of the sludge mixture is adjusted to about 60 . During the composting process, water is lost via evaporation. Water loss is driven by diffusion, air exchange, and heat generation. Some water can leach out of the mixture. Water is gained by precipitation (for uncovered systems) and as a product of respiration. In general, a net loss of water occurs. The final mixture has a moisture content of about 40 . As noted, both too high and too low levels are problems.