Jundiz recycling plant is the first of Basque Country (autonomous community). Zabalgarbi, the facility receives wastes from Bilbao, not recycled. It is similar to an incinerator being planned for disposing of municipal waste in San Sebastian and other municipalities in Gipuzkoa.
Compost, which so far received only Vitoria-Gasteiz waste, will begin to collect in the coming weeks the rest of Álava after proving its effectiveness. The Diputation of Álava invests 1.4 million euros in expanding facilities and new systems that treat and 5,000 tons annually. The expansion of the plant classification of packaging waste in Jundiz already terminated following a statutory investment of 1.4 million euros.
The Department of Environment, under provincial plans mugarri and Waste, proposed the modernization of this plant, which already has 9 years of life and dealing with all packaging waste in the Territory with a movement of 5,000 tons year.
With the aim of improving performance in the classification of packaging, the concession for operating, Jundiz joint venture formed by Yarrow and FCC, has undertaken the expansion of the plant with a new building for the reception of waste. This ship, of 1,000 square meters, in addition to the existing facility of 2,500 square meters, to avoid waste reception outdoors.
In addition to the expansion, the plant makes two important technical improvements. On the one hand, after a feasibility study, is launching a pilot mobile facility for the best use of the "fraction rejection." On the other hand, the plant incorporates a new bag opener which increases the capacity and performance at the beginning of the treatment process.
The facilities are varied. To begin with a ship has reception waste. This ship, of 1000 square meters are attached to the existing 2500 square meters to avoid waste reception outdoors. It has a digester that converts organic waste into fertilizer and methane in the process that gives off the premises to generate electricity. Has also launched a pilot mobile facility for the better use of the fraction of rejection. This machine is intended advantage the %20 of the sewage reaching the plant from the yellow bins. The plant also incorporates a system of open bags to enhance the ability and performance in the treatment process. Finally, includes the construction of a wind turbine that provides the %10 of the electric power consumed by the plant.
The compost, is the product obtained by composting, and constitutes an "average" of decomposition of organic matter, which itself is a good fertilizer. Humus is called the "higher" decomposition of organic matter. The compost humus is used as fertilizer, both organic.
Organic matter decomposes via aerobic or Anaerobic digestion means. Call "composting" aerobic cycle (high presence of oxygen) decomposition of organic matter. Called "digestion" anaerobic cycle (with no or little presence of oxygen) decomposition of organic matter.
The compost is naturally obtained by decomposing aerobic (with oxygen) of organic waste and plant debris, animal excrement and slurry, through the mass reproduction of thermophilic aerobic bacteria that are present naturally in any place (later the continue fermentation the other species of bacteria, fungus and Actinobacteria). Typically, this is to avoid (if possible) the putrefaction of organic waste (excess water, preventing aeration-oxygenation and creates smelly anaerobic biological conditions), although some industrial composting processes used by anaerobic bacteria of putrefaction.
Compost produced in a garden.The compost used in agriculture and gardening as an amendment to the soil fertilizer, but also used in landscaping, erosion control, coatings and soil remediation.
In addition to its direct use, composting involves a strategic and environmentally acceptable solution to the problem created by large urban centers (and their organic household solid waste) and agricultural, forestry and livestock, whose organic waste should be treated. Composting is an alternative technology to others that are not always respectful of natural resources and environment and also have a high cost. In Jundiz they use an inndustrial composting systems that are increasingly being installed as a waste management alternative to landfills, along with other advanced waste processing systems. Mechanical sorting of mixed waste streams combined with anaerobic digestion or in-vessel composting, is called mechanical biological treatment, increasingly used in developed countries due to regulations controlling the amount of organic matter allowed in landfills. Treating biodegradable waste before it enters a landfill reduces global warming from fugitive methane; untreated waste breaks down anaerobically in a landfill, producing landfill gas that contains methane, a potent greenhouse gas.
Large-scale composting systems are used by many urban centers around the world. Co-composting is a technique which combines solid waste with de-watered biosolids, although difficulties controlling inert and plastic contamination from municipal solid waste makes this approach less attractive.
Jundiz recycling plant genereted 5,000 tons of fertilizer last year.Compostplant,opened in November 2006 at the site of Júndiz, swallowed up 50,000 tonnes of waste deposited by the citizens in the gray container, which was incorporated last twelve months. The huge 'stomach' of the facility has become half of those remains at 5,000 tonnes, five million kilos,in organic fertilizer called compost.
Latest wins fertilizer were obtained a few days ago, as the system 'digestive' of Biocompost takes eight weeks to complete the decomposition of food waste in the compound of earthy appearance that the processor tries to sell to farmers. Ensure that there is no risks to crops. In short, each bag an average of ten kilos, 4.40 have become compost, 800 grams have been destined for recycling and the remaining 4.80 kilos, have been concentrated to reduce its volume and minimize the cost to transport to landfill.
Before the start of the "digestion", a complex chain of filters, hoppers and magnets separated from the contents of the bags in metals, plastics and cardboard for recycling and other recyclable materials and articles which by their size, they could not be recycled or decomposed . The first twelve months have brought in 4,000 tons -4 million kilos, which Biocompost sold to recyclers. The remains disposable, which is compressed into blocks to be taken to the landfill, totaling 24,000 tons, almost half of what swallowed by the installation. Industrial systems A large (and over sized) compost pile that is steaming with the heat generated by thermophilic microorganisms.
There are a number of anaerobic organism that are involved in the process of anaerobic digestion including acetic acid-forming bacteria (acetogens) and methane-forming (methanogens). These organisms feed upon the initial feedstock, which undergoes a number of different processes converting it to intermediate molecules including sugars, hydrogen, and acetic acid, before finally being converted to biogas. Different species of bacteria are able to survive at different temperature ranges. Ones living optimally at temperatures between 35–40 °C are called mesophiles or mesophilic bacteria. Some of the bacteria can survive at the hotter and more hostile conditions of 55–60 °C, these are called thermophile.Methanogens come from the domain of archaea. This family includes species that can grow in the hostile conditions of hydrothermal vents. These species are more resistant to heat and can therefore operate at high temperatures, a property that is unique to thermophile. As with aerobic systems the bacteria in anaerobic systems the growing and reproducing microorganisms within them require a source of elemental oxygen to survive. In an anaerobic system there is an absence of gaseous oxygen. Gaseous oxygen is prevented from entering the system through physical containment in sealed tanks. Anaerobes access oxygen from sources other than the surrounding air. The oxygen source for these microorganisms can be the organic material itself or alternatively may be supplied by inorganic oxides from within the input material. When the oxygen source in an anaerobic system is derived from the organic material itself, then the 'intermediate' end products are primarily alcohols, aldehydes, and organic acids plus carbon dioxide. In the presence of specialised methanogens, the intermediates are converted to the 'final' end products of methane, carbon dioxide with trace levels of hydrogen sulfide.In an anaerobic system the majority of the chemical energy contained within the starting material is released by methanogenic bacteria as methane. Populations of anaerobic microorganisms typically take a significant period of time to establish themselves to be fully effective. It is therefore common practice to introduce anaerobic microorganisms from materials with existing populations, a process known as "seeding" the digesters, and typically takes place with the addition of sewage sludge or cattle slurry.
The key process stages of anaerobic digestion There are four key biological and chemical stages of anaerobic digestion: 1. Hydrolysis 2. Acidogenesis 3. Acetogenesis 4. Methanogenesis
In most cases biomass is made up of large organic polymers. In order for the bacteria in anaerobic digesters to access the energy potential of the material, these chains must first be broken down into their smaller constituent parts. These constituent parts or monomers such as sugars are readily available by other bacteria. The process of breaking these chains and dissolving the smaller molecules into solution is called hydrolysis. Therefore hydrolysis of these high molecular weight polymeric components is the necessary first step in anaerobic digestion. Through hydrolysis the complex organic molecules are broken down into simple sugars, acids and fatty acids.
Acetate and Hydrogen are produced in the first stages can be used directly by methanogens. Molecules such as volatile fatty acids with a chain length that is greater than acetate must first be catabolised into compounds that can be directly utilised by methanogens. The biological process of acidogenesis is where there is further breakdown of the remaining components by acidogenic (fermentative) bacteria. Here VFAs are created along with ammonia, carbon dioxide and hydrogen sulfide as well as other by-products. The process of acidogenesis is similar to the way that milk sours.
The third stage anaerobic digestion is acetogenesis. Here simple molecules created through the acidogenesis phase are further digested by an acetogens to produce largely acetic acid as well as carbon dioxide and hydrogen.
The terminal stage of anaerobic digestion is the biological process of methanogenesis. Here methanogens utilise the intermediate products of the preceding stages and convert them into methane, carbon dioxide and water. It is these components that makes up the majority of the biogas emitted from the system.Methanogenesis is sensitive to both high and low pHs and occurs between pH 6.5 and pH 8. The remaining, non-digestible material which the microbes cannot feed upon, along with any dead bacterial remains constitutes the digestate. A simplified generic chemical equation for the overall processes outlined above is as follows: C6H12O6 → 3CO2 + 3CH4
A batch system is the simplest form of digestion. Biomass is added to the reactor at the start of the process in a batch and is sealed for the duration of the process. Batch reactors suffer from odour issues that can be a severe problem when they are emptied. Typically biogas production will be formed with a normal distribution pattern over time. The operator can use this fact to determine when they believe the process of digestion of the organic matter has completed. As the batch digestion is simple and requires less equipment and lower levels of design work it is typically a cheaper form of digestion. In continuous digestion processes organic matter is constantly added (continuous complete mixed)or added in stages to the reactor (continuous plug flow; first in – first out). Here the end products are constantly or periodically removed, resulting in constant production of biogas. A single or multiple digesters in sequence may be used. Examples of this form of anaerobic digestion include continuous stirred-tank reactors (CSTRs), low anaerobic sludge blanket (UASB), Expanded granular sludge bed (EGSB) and Internal circulation reactors (IC). Temperature There are two conventional operational temperature levels for anaerobic digesters, which are determined by the species of methanogens in the digesters: • Mesophilic which takes place optimally around 30-38 °C or at ambient temperatures between 20-45 °C where mesophiles are the primary microorganisms present. • Thermophilic which takes place around 49-57 °C at elevated temperatures up to 70 °C where thermophiles are the primary microorganisms present.
There are a greater number of species of mesophiles than thermophiles . These bacteria are also more tolerant to changes in environmental conditions than thermophiles. Mesophilic systems are therefore considered to be more stable than thermophilic digestion systems. As mentioned above, thermophilic digestion systems are considered to be less stable, the energy input is higher, and more energy is removed from the organic matter. However, the increased temperatures facilitate faster reaction rates and hence faster gas yields. Operation at higher temperatures facilitates greater sterilization of the end digestate. In countries where legislation, such as the Animal By-Products Regulations in the European Union, requires end products to meet certain levels of reduction in the amount of bacteria in the output material, this may be a benefit. Certain processes shred the waste finely and use a short high temperature and pressure pre-treatment (pasteurization / hygienisation) stage that significantly enhances the gas output of the following standard mesophilic stage. The hygienisation process is also applied in order to reduce the pathogenic micro-organisms in the feedstock. Hygienisation / pasteurization may be achieved by using a Landia BioChop hygienisation unit or similar method of combined heat treatment and solids maceration. A drawback of operating at thermophilic temperatures is that more heat energy input is required to achieve the correct operational temperatures. This increase in energy may not be outweighed by the increase in the outputs of biogas from the systems. It is therefore important to consider an energy balance for these systems. There are three principal products of anaerobic digestion: biogas, digestate and water.
Typical composition of biogas
Matter % Methane, CH4 50–75 Carbon dioxide, CO2 25–50 Nitrogen, N2 0–10 Hydrogen, H2 0–1 Hydrogen sulfide, H2S 0–3 Oxygen, O2 0–2
Biogas from sewage works is sometimes used to run a gas engine to produce electrical power; some or all of which can be used to run the sewage works. Some waste heat from the engine is then used to heat the digester. It turns out that the waste heat is generally enough to heat the digester to the required temperatures. The power potential from sewage works is limited.The scope for biogas generation from non-sewage waste biological matter – energy crops, food waste, abattoir waste etc. is much higher, estimated to be capable of about 3,000 MW. Farm biogas plants using animal waste and energy crops are expected to contribute to reducing CO2 emissions and strengthen the grid while providing farmers with additional revenues. Some countries offer incentives in the form of, for example, Feed-in Tariffs for feeding electricity onto the power grid in order to subsidize green energy production.
In Jundiz it is burned methane from organic waste to generate electricity for 12,000 homes. The transformation of waste into compost has been harnessed to generate electricity. And is that the smaller organic waste, 8,000 tons, were shut for a month in a tower to collect the methane produced in decomposition. The combustion of this gas move an alternator that generated six million kilowatts. This electricity, while supporting all of the recycling machinery, led light for 12,000 homes. Finally it is noteworthy that already under construction to install a wind turbine will provide 10% of the electricity consumed by the plant. The intended use is to energy, i.e. converting the waste into fuel which may be used in processes such as cement. This will replace traditional fuels such as diesel and minimizing what is currently sent to landfill Gardelegi.