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Clean Energy Diary

The World Bank development indicators 2008 shows that the wealthiest 20% of the world accounts for 76.6% of total private consumption. The poorest fifth just 1.5%.The report further states,

“Today’s consumption is undermining the environmental resource base. It is exacerbating inequalities. And the dynamics of the consumption-poverty-inequality-environment nexus are accelerating. If the trends continue without change — not redistributing from high-income to low-income consumers, not shifting from polluting to cleaner goods and production technologies, not promoting goods that empower poor producers, not shifting priority from consumption for conspicuous display to meeting basic needs — today’s problems of consumption and human development will worsen. The real issue is not consumption itself but its patterns and effects. Inequalities in consumption are stark. Globally, the 20% of the world’s people in the highest-income countries account for 86% of total private consumption expenditures — the poorest 20% a minuscule 1.3%. More specifically, the richest…

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Waste from Tanneries – An Overview

A worker doing finish grading on sides of leat...

“Tanning” refers to the process by which collagen fibers in a hide react with a chemical agent (tannin, alum or other chemicals). However, the term leather tanning also commonly refers to the entire leather-making process. Hides and skins have the ability to absorb tannic acid and other chemical substances that prevent them from decaying, make them resistant to wetting, and keep them supple and durable. The flesh side of the hide or skin is much thicker and softer. The three types of hides and skins most often used in leather manufacture are from cattle, sheep, and pigs.

A large amount of waste produced by these tanneries is discharged in natural water bodies directly or indirectly through two open drains without any treatment. The water in the low lying areas in developing countries, like India and Bangladesh, is polluted in such a degree that it has become unsuitable for public uses. In summer when the rate of decomposition of the waste is higher, serious air pollution is caused in residential areas by producing intolerable obnoxious odours.

Solids originate from all stages of leather making; they comprise fine leather particles, residues from various chemical discharges and reagents from different waste liquors. These comprise of large pieces of leather cuttings, trimmings and gross shavings, fleshing residues, solid hair debris and remnants of paper bags.

Out of 1000 kg of raw hide, nearly 850 kg is generated as solid wastes in leather processing. Only 150 Kg of the raw material is converted in to leather. Tannery generated huge amount of waste as follows:

  • Fleshing: 56-60%
  • Chrome shaving, chrome splits and buffing dust: 35-40%
  • Skin trimming: 5-7%
  • Hair: 2-5%

Over 80 per cent of the organic pollution load in BOD terms emanates from the beamhouse (pre-tanning); much of this comes from degraded hide/skin and hair matter. During the tanning process at least 300 kg of chemicals (lime, salt etc.) are added per ton of hides. Excess of non-used salts will appear in the wastewater. Because of the changing pH, these compounds can precipitate and contribute to the amount of solid waste or suspended solids. Every tanning process step, with the exception of finishing operations, produces wastewater. An average of 35 m3 is produced per ton of raw hide. The wastewater is made up of high concentration of salts, chromium, ammonia, dye and solvent chemicals etc.

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Introduction to POME

Pure palm oil - production from rural Jukwa vi...
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Palm Oil processing gives rise to highly polluting waste-water, known as Palm Oil Mill Effluent (POME), which is often discarded in disposal ponds, resulting in the leaching of contaminants that pollute the groundwater and soil, and in the release of methane gas into the atmosphere. POME is an oily wastewater generated by palm oil processing mills and consists of various suspended components. This liquid waste combined with the wastes from steriliser condensate and cooling water is called palm oil mill effluent (POME). On average, for each ton of FFB (fresh fruit bunches) processed, a standard palm oil mill generate about 1 tonne of liquid waste with biochemical oxygen demand (BOD) 27 kg, chemical oxygen demand (COD) 62 kg, suspended solids (SS) 35 kg and oil and grease 6 kg

POME has a very high Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD), which is 100 times more than the municipal sewage. POME is a non-toxic waste, as no chemical is added during the oil extraction process, but will pose environmental issues due to large oxygen depleting capability in aquatic system due to organic and nutrient contents. The high organic matter is due to the presence of different sugars such as arabinose, xylose, glucose, galactose and manose. The suspended solids in the POME are mainly oil-bearing cellulosic materials from the fruits. Since the POME is non-toxic as no chemical is added in the oil extraction process, it is a good source of nutrients for microorganisms.

Currently, recovery of renewable organic-based product is a new approach in managing POME. The technology is aimed to recover by-products such as volatile fatty acid, biogas and poly-hydroxyalkanoates to promote sustainability of the palm oil industry. In addition, it is envisaged that POME can be sustainably reused as a fermentation substrate in production of various metabolites through biotechnological advances. In addition, POME consists of high organic acids and is suitable to be used as a carbon source

Anaerobic digestion is widely adopted in the industry as a primary treatment for POME. Biogas is produced in the process in the amount of 20 m3per ton FFB. This effluent could be used for biogas production through anaerobic digestion. At many Palm-oil mills this process is already in place to meet water quality standards for industrial effluent. The gas, however, is flared off. Liquid effluents from Palm Oil mills in Southeast Asia can be used to generate power through gas turbines or gas-fired engines.

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Composting Guidelines

VACAVILLE, CA - APRIL 20:  Birds fly over a co...
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It seems everyone is concerned about the environment and trying to reduce their “carbon footprint”.  I hope this trend will continue and grow as a nationwide way to live and not turn into a fad.  Composting has been around for MANY years.  Composting is a great way to keep biodegradables out of the landfill and to reap the reward of some fabulous “black gold”.  That’s what master gardeners call compost and it’s great for improving your soil.  Plants love it.  Check out 10 Rules to Remember About Composting.

  1. Layer your compost bin with dry and fresh ingredients: The best way to start a compost pile is to make yourself a bin either with wood or chicken wire.  Layering fresh grass clippings and dried leaves is a great start.
  2. Remember to turn your compost pile: As the ingredients in your compost pile start to biodegrade they will start to get hot.  To avoid your compost pile rotting and stinking you need to turn the pile to aerate it.  This addition of air into the pile will speed up the decomposition.
  3. Add water to your compost pile: Adding water will also speed up the process of scraps turning into compost.  Don’t add too much water, but if you haven’t gotten any rain in a while it’s a good idea to add some water to the pile just to encourage it along.
  4. Don’t add meat scraps to your pile: Vegetable scraps are okay to add to your compost pile, but don’t add meat scraps.  Not only do they stink as they rot, but they will attract unwanted guests like raccoons that will get into your compost bin and make a mess of it.
  5. If possible have more than one pile going: Since it takes time for raw materials to turn into compost you may want to have multiple piles going at the same time.  Once you fill up the first bin start a second one and so on.  That way you can allow the ingredient in the first pile to completely transform into compost and still have a place to keep putting your new scraps and clippings.  This also allows you to always keep a supply of compost coming for different planting seasons.
  6. Never put trash in your compost pile: Just because something says that it is recyclable it doesn’t mean that it should necessarily go into the compost bin.  For example, newspapers will compost and can be put into a compost pile, but you will want to shred the newspapers and not just toss them in the bin in a stack.  Things like plastic and tin should not be put into a compost pile, but can be recycled in other ways.
  7. Allow your compost to complete the composting process before using: It might be tempting to use your new compost in your beds as soon as it starts looking like black soil, but you need to make sure that it’s completely done composting otherwise you could be adding weed seeds into your beds and you will not be happy with the extra weeds that will pop up.
  8. Straw can be added if dried leaves are not available: Dried materials as well as green materials need to be added to a compost bin.  In the Fall you will have a huge supply of dried leaves, but what do you do if you don’t have any dried leaves?  Add straw or hay to the compost bin, but again these will often contain weed seeds so be careful to make sure they are completely composted before using them.
  9. Egg Shells and Coffee grounds are a great addition: Not only potato skins are considered kitchen scraps.  Eggshells and coffee grounds are great additions to compost piles because they add nutrients that will enhance the quality of the end product.
  10. Never put pet droppings in your compost pile: I’m sure you’ve heard that manure is great for your garden, but cow manure is cured for quite a while before used in a garden.  Pet droppings are far to hot and acidic for a home compost pile and will just make it stink.

Contributed by Roxanne Porter whose original blogpost can be viewed at http://www.nannypro.com/blog/10-rules-to-remember-about-composting/

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A Glance at Biomass Resources

Manure, a field in Randers in Denmark
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Biomass energy projects provide major business opportunities, environmental benefits, and rural development.  Feedstocks can be obtained from a wide array of sources without jeopardizing the food and feed supply, forests, and biodiversity in the world.

Agricultural Residues

Crop residues encompasses all agricultural wastes such as bagasse, straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. Large quantities of crop residues are produced annually worldwide, and are vastly underutilised. Rice produces both straw and rice husks at the processing plant which can be conveniently and easily converted into energy. Significant quantities of biomass remain in the fields in the form of cob when maize is harvested which can be converted into energy. Sugar cane harvesting leads to harvest residues in the fields while processing produces fibrous bagasse, both of which are good sources of energy. Harvesting and processing of coconuts produces quantities of shell and fibre that can be utilized.

Current farming practice is usually to plough these residues back into the soil, or they are burnt, left to decompose, or grazed by cattle. These residues could be processed into liquid fuels or thermochemical processed to produce electricity and heat. Agricultural residues are characterized by seasonal availability and have characteristics that differ from other solid fuels such as wood, charcoal, char briquette. The main differences are the high content of volatile matter and lower density and burning time.

Animal Waste

There are a wide range of animal wastes that can be used as sources of biomass energy. The most common sources are animal and poultry manures. In the past this waste was recovered and sold as a fertilizer or simply spread onto agricultural land, but the introduction of tighter environmental controls on odour and water pollution means that some form of waste management is now required, which provides further incentives for waste-to-energy conversion.

The most attractive method of converting these waste materials to useful form is anaerobic digestion which gives biogas that can be used as a fuel for internal combustion engines, to generate electricity from small gas turbines, burnt directly for cooking, or for space and water heating.

Forestry Residues

Forestry residues are generated by operations such as thinning of plantations, clearing for logging roads, extracting stem-wood for pulp and timber, and natural attrition. Harvesting may occur as thinning in young stands, or cutting in older stands for timber or pulp that also yields tops and branches usable for biomass energy. Harvesting operations usually remove only 25 to 50 percent of the volume, leaving the residues available as biomass for energy.

Stands damaged by insects, disease or fire are additional sources of biomass. Forest residues normally have low density and fuel values that keep transport costs high, and so it is economical to reduce the biomass density in the forest itself.

Wood Wastes

Wood processing industries primarily include sawmilling, plywood, wood panel, furniture, building component, flooring, particle board, moulding, jointing and craft industries. Wood wastes generally are concentrated at the processing factories, e.g. plywood mills and sawmills. The amount of waste generated from wood processing industries varies from one type industry to another depending on the form of raw material and finished product.

Generally, the waste from wood industries such as saw millings and plywood, veneer and others are sawdust, off-cuts, trims and shavings. Sawdust arise from cutting, sizing, re-sawing, edging, while trims and shaving are the consequence of trimming and smoothing of wood. In general, processing of 1,000 kg of wood in the furniture industries will lead to waste generation of almost half (45 %), i.e. 450 kg of wood. Similarly, when processing 1,000 kg of wood in sawmill, the waste will amount to more than half (52 %), i.e. 520 kg wood.

Industrial Wastes

The food industry produces a large number of residues and by-products that can be used as biomass energy sources. These waste materials are generated from all sectors of the food industry with everything from meat production to confectionery producing waste that can be utilised as an energy source.

Solid wastes include peelings and scraps from fruit and vegetables, food that does not meet quality control standards, pulp and fibre from sugar and starch extraction, filter sludges and coffee grounds. These wastes are usually disposed of in landfill dumps.

Liquid wastes are generated by washing meat, fruit and vegetables, blanching fruit and vegetables, pre-cooking meats, poultry and fish, cleaning and processing operations as well as wine making.

These waste waters contain sugars, starches and other dissolved and solid organic matter. The potential exists for these industrial wastes to be anaerobically digested to produce biogas, or fermented to produce ethanol, and several commercial examples of waste-to-energy conversion already exist.

Pulp and paper industry is considered to be one of the highly polluting industries and consumes large amount of energy and water in various unit operations. The wastewater discharged by this industry is highly heterogeneous as it contains compounds from wood or other raw materials, processed chemicals as well as compound formed during processing.  Black liquor can be judiciously utilized for production of biogas using anaerobic UASB technology.

Municipal Solid Wastes and Sewage

Millions of tonnes of household waste are collected each year with the vast majority disposed of in open fields. The biomass resource in MSW comprises the putrescibles, paper and plastic and averages 80% of the total MSW collected. Municipal solid waste can be converted into energy by direct combustion, or by natural anaerobic digestion in the engineered landfill. At the landfill sites the gas produced by the natural decomposition of MSW (approximately 50% methane and 50% carbon dioxide) is collected from the stored material and scrubbed and cleaned before feeding into internal combustion engines or gas turbines to generate heat and power. The organic fraction of MSW can be anaerobically stabilized in a high-rate digester to obtain biogas for electricity or steam generation.

Sewage is a source of biomass energy that is very similar to the other animal wastes. Energy can be extracted from sewage using anaerobic digestion to produce biogas. The sewage sludge that remains can be incinerated or undergo pyrolysis to produce more biogas.

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Rationale for Aluminium Recycling

Shredded aluminium beverage cans.
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Aluminium is used extensively in aircraft, building construction, electrical transmission and consumer durables such as fridges, cooking utensils and air conditioners as well as in food processing equipment and cans. Infact, the use of aluminum exceeds that of any other metal except iron. Aluminium is the second most widely used metal whereas the aluminum can is the most recycled consumer product in the world. Aluminium exposed to fires at dumps can be a serious environmental problem in the form of poisonous gases and mosquito breeding. Recycled aluminium can be utilized for almost all applications, and can preserve raw materials and reduce toxic emissions, apart from significant energy conservation.

The demand for aluminium products is growing steadily because of their positive contribution to modern living. Aluminium finds extensive use in air, road and sea transport; food and medicine; packaging; construction; electronics and electrical power transmission. Aluminum has a high market value and continues to provide an economic incentive to recycle it. The excellent recyclability of aluminium, together with its high scrap value and the low energy needs during recycling make aluminium lightweight solutions highly desirable.

The contribution of the recycled metal to the global output of aluminium products has increased from 17 percent in 1960 to 34 percent today, and expected to rise to almost 40 percent by 2020. Global recycling rates are high, with approximately 90 per cent of the metal used for transport and construction applications recovered, and over 60 per cent of used beverage cans are collected.

Aluminium does not degrade during the recycling process, since its atomic structure is not altered during melting. Aluminium recycling is both economically and environmentally effective, as it requires a lot less energy to recycle than it does to mine, extract and smelt aluminium ore.  Recycled aluminium requires only 5% of the energy used to make primary aluminium, and can have the same properties as the parent metal. However, in the course of multiple recycling, more and more alloying elements are introduced into the metal cycle. This effect is put to good use in the production of casting alloys, which generally need these elements to attain the desired alloy properties.

The industry has a long tradition of collecting and recycling used aluminium products. Over the years, USA and European countries have developed robust separate collection systems for aluminium packaging with a good degree of success. Recycling aluminium reduces the need for raw materials and reduces the use of valuable energy resources. Recycled aluminium is made into aircraft, automobiles, bicycles, boats, computers, cookware, gutters, siding, wire and cans.

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Energy Recovery from Tannery Wastes

The conventional leather tanning technology is highly polluting as it produces large amounts of organic and chemical pollutants. Wastes generated by the leather processing industries pose a major challenge to the environment. According to conservative estimates, about 600,000 tons per year of solid waste are generated worldwide by leather industry and approximately 40–50% of the hides are lost to shavings and trimmings.

The energy generated by anaerobic digestion or gasification of tannery wastes can be put to beneficial use, in both drying the wastes and as an energy source for the tannery’s own requirements, CHP or electricity export from the site. A large amount of the energy recovered is surplus to the energy conversion process requirements and can be reused by the tannery directly. Infact, implementation of waste-to-energy systems have the potential to make the industry self-sufficient in terms of thermal energy requirements. Tanneries are major energy users, and requires up to 30 kW of energy to produce a single finished hide. Thus, waste-to-energy plant in a tannery promotes the production of electricity from decentralized renewable energy sources, apart from resolving serious environmental issues posed by leather industry wastes.

To read the full article, please visit http://www.altenergymag.com/emagazine.php?art_id=1499

BioEnergy Consult- Provider of Waste-to-Energy Solutions

BioEnergy Consult is committed to the development of sustainable energy systems based on non-food renewable resources and different types of wastes. Our primary mission is to promote Renewable Energy and Sustainable Development worldwide, particularly in developing countries. We are actively engaged in the conceptualization, promotion, implementation, development and financing of Biomass Energy, Waste-to-Energy, Sustainable Biofuels, Waste Management and Alternative Energy ventures in different parts of the world.

BioEnergy Consult promises to address many environmental issues, especially global warming and greenhouse gases emissions, and foster sustainable development among poor communities. The potential role of alternative energy systems in transforming global energy outlook, and addressing climate change concerns, is enormous. We endeavour to bring Sustainable Energy Technologies within the reach of developing countries and to create a mass awareness about the challenges posed by environmental issues like Climate Change and Global Warming.

BioEnergy Consult is an organization with a well-defined mission: To provide cost-effective sustainable solutions through environmentally-safe and well-proven Alternative Energy Systems and Waste-to-Energy Technologies to ensure better Quality of Life.

BioEnergy Consult welcomes inquiries, comments and feedback from entrepreneurs, technology firms, governments, NGOs, investors, social groups, researchers and general public. Please feel free to contact us for business inquiries, partnership, collaboration, expert opinion, discussion or information.

Email: info@bioenergyconsult.com

Website: http://www.bioenergyconsult.com

Waste-to-Energy Projects in India – Technical Issues

For self-sustaining combustion, there should be a heat content of at least 2500 kcal/kg (about 5000 Btu/lb). Usually below 1500 kcal/kg, it is not recommended for combustion. Indian MSW is infamous for its low heat content (770 to 1000 kcal/kg, on dry basis, sometimes as low as 600 kcal/kg), high moisture content (30 to 55 % by weight) and high inert contents (30 to 50 % by weight). It is a fact that Indian MSW is not directly suitable for incineration. Waste preparation is a must for incinerating Indian MSW. Waste should be dried; inerts removed and heat content improved to about 2500 kcal/kg.

In order to determine whether a thermal processing project is a feasible waste management alternative for any city, the following questions should be addressed:

  • Is source-segregation practiced in the target area?
  • Is the thermochemical technology approved by the MNRE and the CPCB?
  • Is there a buyer for the energy (electricity/CHP) produced by the energy recovery facility?
  • Is there strong political and public support for a WTE facility?
  • Are there enough funds to establish state-of-the-art small modular gasification / pyrolysis plant?

Elements of successful Advanced Thermal WTE Project

  • Waste segregation
  • Waste receiving and storage capability
  • Waste preparation plant
  • Gasification/pyrolysis process
  • Syngas treatment process
  • CHP / Power generation