This method produces a uniform product and can be remotely located. However, turning the compost can be labor intensive or require expensive equipment. Windrows are typically used for large volumes which can require a lot of space.
In addition, windrows can have odor problems, and have leachate concerns if exposed to rainfall. Bins using wire mesh or wooden frames allow good air circulation, are inexpensive, and require little labor. Three chamber bins allow for faster compost production utilizing varying stages of decomposition.
Bin composting is typically used for small amounts of food waste. This three-bin system can handle significant quantities of materials. It also allows staged composting, by using one section for storing compostable materials, one section for active composting, and one section for curing or finished compost.
Note: You can use discarded wooden pallets instead of new wood to make a three-bin system. In-vessel systems using perforated barrels, drums, or specially manufactured containers are simple to use, easy to turn, require minimal labor, are not weather sensitive, and can be used in urban and public areas.
The initial investment can be high and handling volumes are typically low. Vermicomposting uses worms to consume the food waste and utilizes its castings as high quality compost. This is usually done in containers, bins, or greenhouses. Typically 1 pound of worms can eat 4 pounds waste per week. Many schools use this type of composting as an environmental education tool.
Worm castings bring a premium price but the investment in worm stocking may be high depending on the size of the operation. If too much waste is added anaerobic conditions may occur.
In addition, worms cannot process meat products. Proper nutrient mix, or carbon to nitrogen ratio C:N is important for bacteria to process organic material into compost. The optimum ratio to begin composting is If the ratio increases decomposition is slowed, if the ratio decreases foul odors and nitrogen loss can occur. Food waste is typically , fruit waste , leaves , bark , and sawdust For example, a recipe using 1 part leaves and 1 part food waste by volume would achieve close to a ratio.
It may be worthwhile to contact your county agricultural extension agent or the University of Georgia for information on obtaining lab analysis of the feedstocks in your compost mix.
A moisture content of 60 percent is optimal for microorganisms to breakdown the compost. Moisture contents above 70 percentcreate anaerobic conditions, slow down the process and can create foul odors.
Moisture below 50 percent also slows down the decomposition process. The moisture content of fresh food waste is 80 to 90 percent, sawdust is 25 percent, and yard waste is 70 percent.
Compost with a proper moisture content will form a clump and will slightly wet your hand when squeezed. If the clump drips water, it is too wet and may require additional aeration or more bulking agent. If the compost falls through your fingers, it is too dry and may need water additions or more food waste. Aeration or oxygen is essential for optimum microorganism populations to effectively breakdown the composting material. This can be done by turning, mixing, the use of blowers, fans, aeration tubes, aeration holes, or raising the compost off the ground.
Particle size can affect the rate of decomposition of compost. The smaller the particles the more aeration the compost receives and microorganisms can break down smaller pieces faster. This can be accomplished by shredding, chipping, chopping, or cutting composted materials before they enter the compost pile. PH levels from 6. Proper C:N ratios should create optimum pH levels. Starting with a fairly neutral pH will ensure high levels of microorganisms for efficient decomposition.
Temperature of the compost is important while biological activity takes place in the decomposition process. Low outside temperature slow down the process, while warmer conditions speed up the process.
Mesophillic bacteria function between 50 andf degrees F to begin the composting process. Thermophillic bacteria take over and thrive between to degrees F. These high temperatures are what destroy weed seeds and pathogens in the compost.
Some composting manures can reach temperatures of degrees F. However, temperatures above degrees F may char the compost or create conditions suitable for spontaneous combustion. Mature or stable compost is similar to humus in appearance, smell, and touch. Gupta et al. At days 14 and 28, except for PHA-treated waste, reduction in VS values of CaCl 2 -treated mixtures was not markedly different from the control; whereas, TSP- and RP-treated vermicomposts follow same pattern with a sudden drop between days 42 and 56, respectively.
Reduction in volatile solids content during vermicomposting of the waste mixtures could be as a result of the disintegration process by microbial activity and loss of carbon in the form of CO 2 Khwairakpam and Bhargava ; Singh and Kalamdhad b. Utilization of carbon by microorganism as a primary energy source for their growth during the vermicomposting process might also cause the reduction of volatile solids Khwairakpam and Bhargava ; Levanon and Pluda Singh and Kalamdhad a revealed that OM decreased with the amount of cattle manure inclusion when water hyacinth was subjected to composting.
Nevertheless, decrease of organic matter in this study was not subjected to the quantity of waste mixtures but may be because of the presence of easily available food for earthworms.
At the beginning of the experiment, vermicomposts pH values ranged between 5. However, this effect varied with time as shown by the significant interaction between applied treatments and time Table 2. The trends in which pH increased during vermicomposting corroborated the work of Tripathi and Bhardwaj and Loh et al. However, this present study contradicted the works of Haimi and Huhta ; Ndegwa et al.
Electrical Conductivity which varied from 4. Two treatments, RP and control shadowed self-same patterns, with abrupt drop between days 42 and 56 Fig. Electrical conductivity as reported by different scientists either increased or decreased during vermicomposting process, some workers reported decrease in electrical conductivity Garg et al.
The decrease has been attributed to a decrease in ions after forming a complex whereas the increase has been attributed to the degradation of organic matter to release cations and release of different mineral salts in available forms such as phosphate, ammonium, and potassium.
The C:N ratio declined meaningfully with time, respectively, at supplementary P-nutrient source; however, there were obvious differences between different P-source treatments up to 28 days, beyond which differences were minimal except for CaCl 2 -treated waste mixtures that spread wider apart Fig.
More decrease in C:N ratio was witnessed past day 28 till the end of the trial but the outcomes of enhanced P-nutrient sources were not meaningfully altered apart from CaCl 2 -treated vermicompost. Final C:N ratios were in the range of 10—12 in vermicompost treated with P-nutrient source fertilizer, whereas control and CaCl 2 -treated vermicompost had C:N ratios of 14 and 22, respectively Fig.
Thus, the addition of P-nutrient bearing source aided reduction of vermicompost C:N ratio and in turn enhanced cow dung—waste paper mixtures vermidegradation at the early stages of vermicomposting up to day 28, beyond which treatment effect was minimal. However, vermicompost treated with CaCl 2 declined minimally but not lower than 22 at day 56 Fig. Bernal et al. A linear increase in ammonium was observed from day zero to day 28 and sharply declined thereafter till termination of the experiment at day 56 Fig.
Nitrate—nitrite in the vermicompost followed the same linearly increasing pattern up to day 14 with higher increment observed where TSP was included, while the lowest nitrate—N substance were recorded with compost treated with CaCl 2 till 28 days Fig. A sharp increment was noticed from day 28 till day 42 in all the treatments except from mixtures blended with CaCl 2.
Although Bernal et al. Another reason behind this augmentation could be the closeness and activity of worms in the substrate and discharge of chemicals as reported by Mupondi et al. Addition of treatments into waste mixtures had significant effect on the amount of P discharge. In case of RP and Control, they followed similar pattern from the beginning till 56th day, while CaCl 2 -treated vermicompost remained the lowest up to termination of the experiment Table 3.
But Parvaresh et al. According to Bhattacharya and Chattopadhyay , phosphate bacteria enable the dissolution of P from P-bearing minerals through the production of phosphatase enzymes. Humification parameters [polymerization index PI , HI, and HR] of waste mixtures were affected by all treatments during vermicomposting period.
These effects were similar to the trend observed in C:N ratio as shown in Table 1. At the beginning of vermicomposting up to 14 days, all treated waste materials had the same PI of 0. However, as vermicomposting progressed 28 days , changes in PI were noticed. Similarly, humification indexes HI from day zero to day 14 of vermicomposting were not different when compared with the control Fig.
The added P-nutrient sources followed the same trend for humification ratio HR in vermicompost from the beginning to the end of the study period Fig.
Roletto et al. None of the extracts from the final vermicomposted products treated with P or Ca sources had any constrain on seed sprouting of test crops Table 4. Tomato had the main important value of This can be because of well advance of decay of natural substrates and diminishment of phytotoxic mixes coming about because of vermicompost maturing. All extracts used for seed germination test were freed of phytotoxicity except were CaCl 2 extract was used because of high EC in regard of Ca-treated product and resilience of tested seeds to salinity Tiquia Our results correspond to Paradelo et al.
Bustamante et al. Of the three P sources tested, water-soluble P vermicomposts had the highest germination indices for all crops tested indicating the superiority of these vermicomposts. Figure 6 c—f confirmed the degree of humification of the resultant vermicompost from SEM results.
At the beginning of the experiment, the waste mixture had a compressed group both of roughage and protein fibres morphologically Fig. However, where earthworms and TSP, RP, PHA were added, highly degraded, fine grain texture vermicompost was produced from the grinding nature exhibited by the earthworm Fig. The level of grinding activities of the waste materials by earthworms became more intensified with treatments.
Vermicompost produced from TSP readily available P enrichment had well-humified and high aggregate particles which was evident in the humification parameters, showing the importance of P rather than Ca CaCl 2 during bioconversion of waste.
Additional affirmation of intense mixtures decomposition is also revealed from SEM pictures Fig. The resultant SEM photo of the vermicompost exhibited a specific physical appearance that portrayed a scattered separated minute in nature contrast to the control.
Thus, SEM images in this study were similar to that of Lim et al. The wider contrasts in the degree of decomposition observed from various treatments at 14th and 28th days agreed with the time of most extreme microbial action Unuofin et al.
Scanning electron microscope pictures showing P and Ca source effects on vermicompost morphological properties. The results of this study have demonstrated that phosphorous and not calcium is responsible for the enhanced biodegradation of waste mixtures mixed with P bearing like rock phosphate during vermicomposting. However, the use of water-soluble P sources to enhance vermicomposting may not be justifiable where impure and less expensive P sources such as rock phosphates are available as their use can result in equally mature and P-enriched vermicomposts in 6—8 weeks.
However, it could also be partially linked to meeting the P nutritional requirements of the earthworms. This latter effect will need to be explored in future studies. CAB International, Wallingford. For most efficient composting, use a pile that is between 3 feet cubed and 5 feet cubed cu. This allows the center of the pile to heat up sufficiently to break down materials. Smaller piles can be made but will take longer to produce finished compost.
You may also want to have two piles, one for finished compost ready to use in the garden, and the other for unfinished compost. If the pile has more brown organic materials, it may take longer to compost. You can speed up the process by adding more green materials or a fertilizer with nitrogen use one cup per 25 square feet.
The surface area of the materials effects the time needed for composting. By breaking materials down into smaller parts chipping, shredding, mulching leaves , the surface area of the materials will increase. This helps the bacteria to more quickly break down materials into compost.
Finally, the number of times the pile is turned influences composting speed. By turning more frequently about every weeks , you will produce compost more quickly. Waiting at least two weeks allows the center of the pile to heat up and promotes maximum bacterial activity. The average composter turns the pile every weeks. When turning the compost pile, make sure that materials in the center are brought to the outsides, and that materials from the outside edges are brought to the center. With frequent turning, compost can be ready in about 3 months, depending on the time of year.
In winter, the activity of the bacteria slows, and it is recommended that you stop turning the pile after November to keep heat from escaping the pile's center. The screening isn't perfect — small shreds of plastic are still visible in the resulting compost — but it gets the amount of plastic low enough to meet standards.
The heavier contaminants — glass, metal, dirt and shells — fall to the bottom and caught in the catch basin of the hydro pulper before being removed.
Even items that could be recycled, such as metal and glass, end up as garbage. The organic waste becomes a sludge, ground up and sopping wet, before being brought to large tanks called anaerobic digesters.
In the digesters, micro-organisms, in the absence of oxygen, break down the material to produce the pre-compost stage — called digester solids — and release biogas, a mix of methane and carbon dioxide. The digester solids are then sent to a third-party company — in this case, All Treat Farms, about two hours west of Toronto — to be heated, aerated and turned into usable compost.
The biogas is filtered out with big fans, and used to mix and heat the anaerobic digesters, as well as burned to keep the facility warm during the winter months. Some of it is also used to heat the digester tanks in the facility. Disco Road currently burns the remaining gas. In the future, the City of Toronto hopes to sell it as a more renewable and sustainable type of fuel used for heating and vehicles. All liquids — liquid digestate, rainwater and all other water used on-site — is collected and purified so that it can supply most of the facility's water needs, mainly for drinking and to clean instruments.
Aerobic digestion creates nutrient-rich fertilizer without diverting partially decomposed waste to a different facility. It can still be a complicated, multi-step process, where staff measure how much water, air, carbon and nitrogen-rich materials go into the pile.
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