A Glance at Woody Biomass Resources

Woody biomass resources range from corn kernels to corn stalks, from soybean and canola oils to animal fats, from prairie grasses to hardwoods, and even include algae. Woody biomass may be used for energy production at different scales, including large-scale power generation, CHP, or small-scale thermal heating projects. Some of the major sources of woody biomass are being discussed in the following paragraphs:

Pulp and Paper Industry Residues

The largest source of energy from wood is the waste product from the pulp and paper industry called black liquor. Logging and processing operations generate vast amounts of biomass residues. Wood processing produces sawdust and a collection of bark, branches and leaves/needles. A paper mill, which consumes vast amount of electricity, utilizes the pulp residues to create energy for in-house usage.

Forest Residues

Forest harvesting is a major source of biomass for energy. 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 bioenergy.

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.

Crop Residues

Crop residues encompasses all agricultural wastes such as straw, stem, stalk, leaves, husk, shell, peel, pulp, stubble, etc. which come from cereals (rice, wheat, maize or corn, sorghum, barley, millet), cotton, groundnut, jute, legumes (tomato, bean, soy) coffee, cacao, tea, fruits (banana, mango, coco, cashew) and palm oil.

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.

Energy Crops

Dedicated energy crops are another source of woody biomass for energy. These crops are fast-growing plants, trees or other herbaceous biomass which are harvested specifically for energy production. Rapidly-growing, pest-tolerant, site and soil-specific crops have been identified by making use of bioengineering.

For example, operational yield in the northern hemisphere is 10-15 tonnes/ha annually. A typical 20 MW steam cycle power station using energy crops would require a land area of around 8,000 ha to supply energy on rotation.

Miscanthus-Elephant-Grass

Herbaceous energy crops are harvested annually after taking two to three years to reach full productivity. These include grasses such as switchgrass, elephant grass, bamboo, sweet sorghum, wheatgrass etc. Short rotation woody crops are fast growing hardwood trees harvested within five to eight years after planting. These include poplar, willow, silver maple, cottonwood, green ash, black walnut, sweetgum, and sycamore.

Industrial crops are grown to produce specific industrial chemicals or materials, e.g. kenaf and straws for fiber, and castor for ricinoleic acid. Agricultural crops include cornstarch and corn oil soybean oil and meal wheat starch, other vegetable oils etc. Aquatic resources such as algae, giant kelp, seaweed, and microflora also contribute to bioenergy feedstock.

Urban Wood Wastes

Such waste consists of lawn and tree trimmings, whole tree trunks, wood pallets and any other construction and demolition wastes made from lumber. The rejected woody material can be collected after a construction or demolition project and turned into mulch, compost or used to fuel bioenergy plants.

What You Need to Know About Food Waste Management

Food waste is an untapped energy source that mostly ends up rotting in landfills, thereby releasing greenhouse gases into the atmosphere. Food waste is difficult to treat or recycle since it contains high levels of sodium salt and moisture, and is mixed with other waste during collection. Major generators of food wastes include hotels, restaurants, supermarkets, residential blocks, cafeterias, airline caterers, food processing industries, etc.

In United States, food waste is the third largest waste stream after paper and yard waste. Around 13 percent of the total municipal solid waste generated in the country is contributed by food scraps. According to USEPA, more than 35 million tons of food waste are thrown away into landfills or incinerators each year, which is around 40 percent of all food consumed in the country.

As far as United Kingdom is concerned, households throw away around 4.5 million tons of food each year. Food wastage in Canada causes 56.6 million tonnes of CO2-equivalent emissions. These statistics are an indication of tremendous amount of food waste generated all over the world.

food_waste

Food Waste Management Strategy

The proportion of food waste in municipal waste stream is gradually increasing and hence a proper food waste management strategy needs to be devised to ensure its eco-friendly and sustainable disposal. The two most common methods for food waste recycling are:

  • Composting: A treatment that breaks down biodegradable waste by naturally occurring micro-organisms with oxygen, in an enclosed vessel or tunnel;
  • Anaerobic digestion (AD): A treatment that breaks down biodegradable waste in the absence of oxygen, producing a renewable energy (biogas) that can be used to generate electricity and heat.

Currently, only about 3 percent of food waste is recycled throughout USA, mainly through composting. Composting provides an alternative to landfill disposal of food waste, however it requires large areas of land, produces volatile organic compounds and consumes energy. Consequently, there is an urgent need to explore better recycling alternatives.

Anaerobic digestion has been successfully used in several European and Asian countries to stabilize food wastes, and to provide beneficial end-products. Sweden, Austria, Denmark, Germany and England have led the way in developing new advanced biogas technologies and setting up new projects for conversion of food waste into energy.

biogas-enrichment

Of the different types of organic wastes available, food waste holds the highest potential in terms of economic exploitation as it contains high amount of carbon and can be efficiently converted into biogas and organic fertilizer. Food waste can either be used as a single substrate in a biogas plant, or can be co-digested with organic wastes like cow manure, poultry litter, sewage, crop residues, abattoir wastes, etc.

Food waste is one of the single largest constituent of municipal solid waste stream. Diversion of food waste from landfills can provide significant contribution towards climate change mitigation, apart from generating revenues and creating employment opportunities. Rising energy prices and increasing environmental pollution makes it more important to harness renewable energy from food wastes.

Anaerobic digestion technology is widely available worldwide and successful projects are already in place in several European as well as Asian countries which makes it imperative on waste generators and environmental agencies in USA to strive for a sustainable food waste management system.

Everything You Need to Know About PVC Recycling

PVC is one of the most widely used plastics worldwide. A major problem in the recycling of PVC is the high chlorine content in raw PVC and high levels of hazardous additives added to the polymer to achieve the desired material quality. As a result, PVC requires separation from other plastics before recycling. PVC products have an average lifetime of 30 years, with some reaching 50 or more years.  This means that more PVC products are reaching the end-of-life and entering the waste stream, and the amount is likely to increase significantly in the near future.

pvc-recycling

PVC Recycling Methods

Currently, PVC plastic is being recycled by either of the two ways:

  • Mechanical recycling – This involves mechanically treating the waste (e.g. grinding) to reduce it into smaller particles.  The resulting granules, called recyclate, can be melted and remolded into different products, usually the same product from which it came.
  • Feedstock recycling – Chemical processes such as pyrolysis, hydrolysis and heating are used to convert the waste into its chemical components.  The resulting products – sodium chloride, calcium chloride, hydrocarbon products and heavy metals to name a few – are used to produce new PVC, as feed for other manufacturing processes or as fuel for energy recovery.

In mechanical recycling, because no chemical reaction is involved, the recyclate retains its original composition. This poses a recycling challenge because PVC products, depending on their application, contain different additives.  For example, rigid PVC is unplasticized whereas flexible PVC is added plasticizers because this additive increases the plastic’s fluidity and thus, its flexibility. Even products used for the same application may still differ in composition if they have different manufacturers.

When different kinds of PVC waste are fed to a mechanical recycler, the resulting product’s composition is difficult to predict, which is problematic because most PVC products, even recycled ones, require a specific PVC content.  In order to produce a high-quality recylate, the feed ideally should not be mixed with other kinds of plastic and should have a uniform material composition.Material recycling is therefore more applicable for post-industrial waste than for post-consumer waste.

PVC-waste

Feedstock recycling is seen to be complementary to conventional mechanical recycling as it is able to treat mixed or unsorted PVC waste and recover valuable materials.  However, a study showed that feedstock recycling (or at least the two that was considered) incurred higher costs than landfilling, primarily due to the low value of the recovered products. This provides little incentive for recyclers to pursue PVC recycling.  This may change in the future as more stringent regulations to protect the environment are enacted.  Some countries in Europe have already banned PVCs from landfills and PlasticsEurope is targeting a “zero plastic to landfill” in Europe by 2020.

Post-industrial waste is relatively pure and comes from PVC production and installation, such as cut-offs from laying of cables or scraps from the installation of window frames.  These are easily recycled since they can be collected directly from processors or installers or even recycled by producers themselves as raw material to manufacture the same product.

Post-consumer waste contains mixed material and has been used for different applications.  These are products that have reached the end-of-life or are replaced due to damage, like pipes from underground, window frames being replaced for renovation and electric cables recovered from demolition. These would require further sorting and cleaning, adding cost to the recycling process.  The recyclate produced is usually of lower quality and consequently of decreased economic value.

Recent Developments

Europe is leading the way for a more sustainable use of PVC with programs, such as RecoVinyl and VinylPlus, where recycling is advanced as one of the ways to use resources more efficiently and to divert as much waste as possible from landfills. Recovinyl, created in 2003, is an initiative of the European PVC industry to advance the sustainable development of the PVC industry by improving production processes, minimise emissions, develop recycling technology and boost the collection and recycling of waste.

Having been successful in all of its goals, including an increase in recycling of PVC across Europe to over 240,000 tonnes a year, in 2011 the PVC industry redefined the role of Recovinyl as part of the ambitious new ten-year VinylPlus sustainable development programme. VinylPlus works in partnership with consumers, businesses, municipalities, waste management companies, recyclers and converter, as well as the European Commission and national and local governments. The goal is to certify those companies who recycle PVC waste and those accredited converting companies who purchase recyclate to manufacture new products and applications.

Even if some types of PVC recycling are not feasible or economically viable at present, it will likely be reversed in the future as governments, manufacturers, consumers and other stakeholders create programs that innovate and find ways to achieve a sustainable future for the PVC industry.

Waste Management in Iraq

Iraq is one of the most populous Arab countries with population exceeding 32 million. Rapid economic growth, high population growth, increasing individual income and sectarian conflicts have led to worsening problem of solid waste management problem in Iraq. Iraq generates around 31,000 tons of solid waste every day with per capita waste generation exceeding 1.4 kg per day. Baghdad alone produces more than 1.5 million tons of solid wastes each year.

iraq-wastes

Rapid increase in waste generation is putting tremendous strain on Iraqi waste handling infrastructure which have heavily damaged after decades of conflict and mismanagement. In the absence of modern and efficient waste handling and waste disposal infrastructure most of the wastes are disposed in unregulated landfills across Iraq, with little or no concern for both human health and environment. Spontaneous fires, groundwater contamination, surface water pollution and large-scale greenhouse gas emissions have been the hallmarks of Iraqi landfills.

The National Solid Waste Management Plan (NSWMP) for Iraq was developed in 2007 by collaboration of international waste management specialist. The plan contains the recommendations for development and which explains the background for decisions.

The plan states that Iraq will build 33 engineered landfills with the capacity of 600 million m3 in all of the 18 governorates in Iraq by 2027. In addition to constructing landfills the plan also focuses on the collection and transportation, disposable, recycling and reuses systems. Environment education was also taken into consideration to ensure provision of educational system which supports the participation of both communities and individuals in waste management in Iraq.

Besides Iraqi national waste management plan, the Iraqi ministry of environment started in 2008 its own comprehensive development program which is part of the ministry of environment efforts to improve environmental situation in Iraq. Ministry of Municipalities and Public Work, in collaboration with international agencies like UN Habitat, USAID, UNICEF and EU, are developing and implementing solid waste management master plans in several Iraqi governorates including Kirkuk, Anbar, Basra, Dohuk, Erbil, Sulaimaniya and Thi Qar.

Recent Progress

Kirkuk was the first city in Iraq to benefit from solid waste management program when foreign forces initiated a solid waste management program for the city in 2005 to find an environmentally safe solution to the city’s garbage collection and disposal dilemma. As a result the first environmentally engineered and constructed landfill in Iraq was introduced in Kirkuk In February 2007. The 48-acre site is located 10 miles south of Kirkuk, with an expected lifespan of 10–12 years and meets both the U.S. Environmental Protection Agency and European Union Landfill Directive standards.

The Iraqi city of Basra also benefited from international aid with the completion of the first landfill that is compliant with international environmental standards has been completed. Basra solid waste management program developed by UNICEF will not only restore efficient waste collection systems in the city but will also create informal “recycling schools” that will help in spreading environmental awareness in in the city’s society by launching a campaign to educate the public about effective waste disposal practices.

In addition, Basra city program plans to establish a regional treatment and disposal facility and initiate street sweeping crews. Basrah city waste management program is part of the UNICEF program supported by the European Union to develop Iraq’s water and sanitation sector.

Erbil’s solid waste management master plan has also been developed by UNICEF with funding from the European Union. Recently a contract was signed by the Kurdistan Region’s Ministry of Municipalities and Tourism and a Canadian company to recycle the city’s garbage which will involve the construction of two recycling plants in the eastern and western outskirts of Erbil.

UNICEF has also developed a master plan to improve the management of solid waste in Dohuk Governorate which has been finalized in June 2011. Solid waste management master plans for Anbar, Sulaimaniya and Thi Qar governorates are also a part of UNICEF and EU efforts to attaining Iraq’s Millennium Development Goal targets of ensuring environmental sustainability by 2015.

Even though all of the effort by the international organizations are at local level and still not enough to solve solid waste management problem in Iraq, however these initiatives have been able to provide a much needed information regarding the size of the issue and valuable lessened learned used later by the Iraqi government to develop the Iraqi national waste management plan with the support of organizations such as UN Habitat, UNDG Iraq Trust Fund and USAID. The Iraqi national waste management plan is expected to ease the solid waste management problem in Iraq in the near future.

Zena Fly- Feeding the World on Insect

Meeting an ever increasing demand for food/feed/energy and managing waste have become two of the major global challenges. The global world population is estimated to increase from 7.3 billion in 2015 to 9.7 billion in 2050. Approximately one third of the global food produced for human composition is wasted. Currently, approximately 1.3 billion metric tons of waste are disposed with significant environmental impact as far as greenhouse gases and economic footprints and the current waste management practices are not costly sustainable.

zena-fly-waste-management

Increase in Global Energy Demand

Global energy demand is estimated to increase from 524 Quadrillion btu in 2010, to 820 Quadrillion btu by 2040 (a 56% increase). Similarly, global demand of food and animal products are projected to increase by 70-100% and 50-70%, respectively, by 2050. To cope up with the demand for animal products, a substantial increase in nutritious animal feed is needed.

On one hand, the production of conventional feedstuff such as soybean meal and fish meal is reported as the major contributor to land occupation, ocean depletion, climate change, water and energy consumption. Moreover, such conventional animal feedstuff are not only limited in supply but also are becoming more expensive over the years. Additionally, there is an already strong and increasing competition for resources such as food, feed and biofuel production.

Need for alternative non-conventional source of food, feed, and fuel

Thus there is a pressing need for identifying and exploring the potential of alternative non-conventional source of food, feed, and fuel, which are economically viable, environmentally friendly, and socially acceptable.

By 2030 the Bio-based Economy is expected to have grown significantly. A pillar of this is biorefining, the sustainable processing of biomass into a spectrum of marketable products and energy. To satisfy this demand biorefineries need to be better integrated, flexible and operating more substantially. This means that a major yield, more efficient use of nutrients and water and greater pest and disease resistance should be achieve.

Zena Fly: A Startup Worth Watching

In this context an Italian-based start-up, Zena Fly, designed an innovative process for the future integrated biorefinery by mimicking nature’s ability. In fact, Zena Fly utilizes the natural insect life cycle to manage large quantity of organic waste produced in urban and industrial context, in order to generate sustainable and valuable by-products. The project of three young entrepreneurs foresees a combined bio-refinery where waste is turned into high-quality by-products by the anaerobic insect digestion.

The Concept

The basic concept is to convert waste into high-valuable products utilizing the black soldier flies (H. illucens), a now globally distributed insect. With a modern technique, the typical insect life cycle of these insects can be utilized in order to manage urban and industrial waste. The voracious larvae can reduce by more than 40-70% (based on the nature of the substrate-waste) the substrate where reared (waste) within 12-14 days.

From the anaerobic waste digestion, large quantity of fine protein meal for feed composition (more than 50-60% in protein), fat, fertilizing oil and other by-products of great interest such as chitin, and high-quality biofuel are then extracted.

Since the adult fly do not feed, and do not fly around for feeding, these animals are exceptionally valuable from a sanitary perspective (larvae has been demonstrate to reduce/eliminate E.coli and Salmonella).

Business Model

Zena Fly business model foresees to replicate their integrated biorefineries next to any waste management companies or industrial production areas where large quantity of waste need to be reduced and transformed. This is a win/win operation, where the waste management cost would be cut in half and the process will generate appealing opportunities for investments in a market where the increasing demand is already way higher than the products availability.

Zena Fly is now seeking for the right partner-investor in order to scale up quickly. For more information, please visit www.zena-fly.com or email us on info@zena-fly.com

Comparison of MSW-to-Energy Processes

MSW-to-Energy is the use of thermochemical and biochemical technologies to recover energy, usually in the form of electricity, steam and other fuels, from urban wastes. The main categories of MSW-to-energy technologies are physical technologies, which process waste to make it more useful as fuel; thermal technologies, which can yield heat, fuel oil, or syngas from both organic and inorganic wastes; and biological technologies, in which bacterial fermentation is used to digest organic wastes to yield fuel. These new technologies can reduce the volume of the original waste by 90%, depending upon composition and use of outputs.

Components of MSW-to-Energy Systems

  1. Front-end MSW preprocessing
  2. Conversion unit (reactor or anaerobic digester)
  3. Gas cleanup and residue treatment plant
  4. Energy recovery plant (optional)
  5. Emissions clean up

Incineration

  • Combustion of raw MSW, moisture less than 50%
  • Sufficient amount of oxygen is required to fully oxidize the fuel
  • Combustion temperatures are in excess of 850oC
  • Waste is converted into CO2 and water concern about toxics (dioxin, furans)
  • Any non-combustible materials (inorganic such as metals, glass) remain as a solid, known as bottom ash (used as feedstock in cement and brick manufacturing)
  • Air pollution control system for fly ash, bottom ash, particulates etc.
  • Needs high calorific value waste to keep combustion process going, otherwise requires high energy for maintaining high temperatures

Anaerobic Digestion

  • Well-known biochemical technology for organic fraction of MSW and sewage sludge.
  • Biological conversion of biodegradable organic materials in the absence of oxygen at mesophilic or thermophilic temperatures.
  • Residue is stabilized organic matter that can be used as soil amendment
  • Digestion is used primarily to reduce quantity of sludge for disposal / reuse
  • Methane gas is generated which is used for heat and power generation.

Gasification

  • Can be seen as between pyrolysis and combustion (incineration) as it involves partial oxidation.
  • Exothermic process (some heat is required to initialize and sustain the gasification process).
  • Oxygen is added but at low amounts not sufficient for full oxidation and full combustion.
  • Temperatures are above 650oC
  • Main product is syngas, typically has net calorific value of 4 to 10 MJ/Nm3
  • Other product is solid residue of non-combustible materials (ash) which contains low level of carbon

Pyrolysis

  • Thermal degradation of organic materials through use of indirect, external source of heat
  • Temperatures between 300 to 850oC are maintained for several seconds in the absence of oxygen.
  • Product is char, oil and syngas composed primarily of O2, CO, CO2, CH4 and complex hydrocarbons.
  • Syngas can be utilized for energy production or proportions can be condensed to produce oils and waxes
  • Syngas typically has net calorific value (NCV) of 10 to 20 MJ/Nm

Plasma Gasification

  • Use of electricity passed through graphite or carbon electrodes, with steam and/or oxygen / air injection to produce electrically conducting gas (plasma)
  • Temperatures are above 3000oC
  • Organic materials are converted to syngas composed of H2, CO
  • Inorganic materials are converted to solid slag
  • Syngas can be utilized for energy production or proportions can be condensed to produce oils and waxes

MSW-to-energy technologies can address a host of environmental issues, such as land use and pollution from landfills, and increasing reliance on fossil fuels. In many countries, the availability of landfill capacity has been steadily decreasing due to regulatory, planning and environmental permitting constraints. As a result, new approaches to waste management are rapidly being written into public and institutional policies at local, regional and national levels.

Composting in Qatar: An Overview

Composting in Qatar is mainly done at the Domestic Solid Waste Management Centre (DSWMC) in Mesaieed, which houses the largest composting facility in the country and one of the largest in the world.  The waste that enters the plant initially goes through anaerobic digestion, which produces biogas that can power the facility’s gas engine and generators, followed by aerobic treatment which yields the final product.

Two types of compost are generated: Grade A (compost that comes from green waste, such as yard/park trimmings, leftovers from kitchen or catering services, and wastes from markets) and Grade B (compost produced from MSW).  The plant started its operation in 2011 and when run at full capacity is able to process 750 tons of waste and produce 52 tons of Grade A compost, 377 tons of Grade B compost, liquid fertilizer which is composed of 51 tons of Grade A compost and 204 tons of Grade B compost, and 129 tons of biogas.

benefits-composting

This is a significant and commendable development in Qatar’s implementation of its solid waste management plan, which is to reduce, reuse, recycle and recover from waste, and to avoid disposing in landfills as much as possible.  However, the large influx of workers to Qatar in the coming years as the country prepares to host the World Cup in 2022 is expected to substantially increase solid waste generation and apart from its investments in facilities like the composting plant and in DSWMC in general, the government may have to tap into the efforts of organizations and communities to implement its waste management strategy.

Future Outlook

Thankfully, several organizations recognize the importance of composting in waste management and are raising awareness on its benefits.  Qatar Green Building Council (QGBC) has been actively promoting composting through its Solid Waste Interest Group.  Last year, they were one of the implementers of the Baytna project, the first Passivhaus experiment in the country.

This project entails the construction of an energy-efficient villa and a comparative study will be performed as to how the carbon footprint of this structure would compare to a conventional villa.  The occupants of the Passivhaus villa will also be made to implement a sustainable waste management system which includes composting of food waste and garden waste, which is meant to lower greenhouse gas emissions compared to landfilling.

Qatar Foundation is also currently developing an integrated waste management system for the entire Education City and the Food Services group is pushing for composting to be included as a method to treat food and other organic waste.  And many may not know this but composting can be and has been done by individuals in their own backyard and can even be done indoors with the right equipment.

Katrin Scholz-Barth, previous president of SustainableQatar, a volunteer-based organization that fosters sustainable culture through awareness, skills and knowledge, is an advocate of composting and has some great resources on how to start and maintain your own composting bin as she has been doing it herself.

A simple internet search will also reveal that producing compost at home is a relatively simple process that can be achieved with minimal tools.  At present, very few families in Qatar are producing their own compost and Scholz-Barth believes there is much room for improvement.

As part of its solid waste management plan as stated in the National Development Strategy for 2011-2016, Qatar aims to maintain domestic waste generation at 1.6 kg per capita per day.  This will probably involve encouraging greater recycling and reuse efforts and the reduction of waste from its source.

It would also be worthwhile to include programs that will promote and boost composting efforts among institutions, organizations and individuals, encouraging them with the fact that apart from its capability of significant waste diversion from landfills, composting can also be an attractive source of income.

Note: The article is being republished with the permission of our collaborative partner EcoMENA. The original article can be viewed at this link.

Food Waste Management in UK

Food waste in the United Kingdom is a matter of serious environmental, economic and social concern that has been attracting widespread attention in recent years. According to ‘Feeding the 5K’ organisation, 13,000 slices of crusts are thrown away every day by a single sandwich factory. More recently, Tesco, one of the largest UK food retailers, has published its sustainability report admitting that the company generated 28,500 tonnes of food waste in the first six months of 2013. TESCO’s report also state that 47% of the bakery produced is wasted. In terms of GHG emissions, DEFRA estimated that food waste is associated with 20 Mt of CO2 equivalent/year, which is equivalent to 3% of the total annual GHG emissions.

Food-Waste-UK

Globally, 1.2 to 2 billion tonnes (30%-50%) of food produced is thrown away before it reaches a human stomach. Food waste, if conceived as a state, is responsible for 3.3 Bt-CO2 equivalent/year, which would make it the third biggest carbon emitter after China and USA.

What makes food waste an even more significant issue is the substantially high demand for food which is estimated to grow 70% by 2050 due to the dramatic increase of population which is expected to reach 9.5 billion by 2075. Therefore, there is an urgent need to address food waste as a globally challenging issue which should be considered and tackled by sustainable initiatives.

A War on Food Waste

The overarching consensus to tackle the food waste issue has led to the implementation of various policies. For instance, the European Landfill Directive (1999/31/EC) set targets to reduce organic waste disposed to landfill in 2020 to 35% of that disposed in 1995 (EC 1999).

More recently, the European Parliament discussed a proposal to “apply radical measures” to halve food waste by 2025 and to designate the 2014 year as “the European Year Against Food Waste”. In the light of IMechE’s report (2013), the United Nations Environment Programme (UNEP) in cooperation with FAO has launched the Save Food Initiative in an attempt to reduce food waste generated in the global scale.

In the UK, WRAP declared a war on food waste by expanding its organic waste programme in 2008 which was primarily designed to “establish the most cost-effective and environmentally sustainable ways of diverting household food waste from landfill that leads to the production of a saleable product”. DEFRA has also identified food waste as a “priority waste stream” in order to achieve better waste management performance.

In addition to governmental policies, various voluntary schemes have been introduced by local authorities such as Nottingham Declaration which aims to cut local CO2 emissions 60% by 2050.

Sustainable Food Waste Management

Engineering has introduced numerous technologies to deal with food waste. Many studies have been carried out to examine the environmental and socio-economic impacts of food waste management options. This article covers the two most preferable options; anaerobic digestion and composting.

In-vessel composting (IVC) is a well-established technology which is widely used to treat food waste aerobically and convert it into a valuable fertilizer. IVC is considered a sustainable option because it helps by reducing the amount of food waste landfilled. Hence, complying with the EU regulations, and producing a saleable product avoiding the use of natural resources.

IVC is considered an environmentally favourable technology compared with other conventional options (i.e. landfill and incineration). It contributes less than 0.06% to the national greenhouse gas inventories. However, considering its high energy-intensive collection activities, the overall environmental performance is “relatively poor”.

Anaerobic Digestion (AD) is a leading technology which has had a rapidly growing market over the last few years. AD is a biologically natural process in which micro-organisms anaerobically break down food waste and producing biogas which can be used for both Combined Heat & Power (CHP) and digestate that can be used as soil fertilizers or conditioners. AD has been considered as the “best option” for food waste treatment. Therefore, governmental and financial support has been given to expand AD in the UK.

AD is not only a food waste treatment technology, but also a renewable source of energy. For instance, It is expected that AD would help the UK to meet the target of supplying 15% of its energy from renewable sources by 2020. Furthermore, AD technology has the potential to boost the UK economy by providing 35,000 new jobs if the technology is adopted nationally to process food waste. This economic growth will significantly improve the quality of life among potential beneficiaries and thus all sustainability elements are considered.

Electrical Waste Collection Strategies in the UK

When disposing of small electrical items from the home, most householders only have the option of visiting their local recycling facility to drop them off. However, in order to meet recycling targets, local authorities in the UK are now considering kerbside (or curbside) collections of small domestic appliances. This is expected to help prevent small electrical items being placed into the general waste/refuse containers from households.

electrical-waste-uk

This waste stream has become a priority as figures show that the average amount of WEEE (waste electrical and electronic equipment) recycled per person is only 1.3kg. The original WEEE directive targeted 4kg per person, as a recycling rate, so there is a considerable shortfall. It is important that householders find it easy to recycle their items in order to increase the rates.

Initial trials have taken place to assess the viability of these kerbside collections and the following conclusions were made:

  • On collections, small electrical items were often damaged, so the reuse of items was less likely.
  • Levels of recycling were encouraging at 140 grams per household.
  • The monetary value of the separated materials of the small items showed that a positive net value could be achieved.

Whilst the potential reuse of small electrical items was reduced it was a positive that local authorities could generate revenues from the collections. Quarterly or bi-annual collection frequencies would ensure volumes of equipment on the collections were maximised. Due to the success of the trials, the UK is likely to see more and more local authorities adopt some form of collection schedule for small electrical waste items.

An old refrigerator uses almost four times the electricity of a new one

Larger electrical items such as washing machines and fridge freezers pose a different collection issue. Some local authorities offer a collection service for bulky electrical items, however due to their size, weight and manpower requirements there is often a charge. As with smaller electrical items, you can deliver these to the local recycling facility, but you may not be able to fit these into your own vehicle. It is best to check with the local recycling facility on the options available and possibly even if they allow large, commercial sized vehicles onto site.

The collection of electrical wastes from households in the UK will ultimately increase the amount of electrical waste being recycled in the UK. It will also further promote the recycling of such items instead of placing them into general waste containers. Going forward it is hoped that more local authorities will adopt a collection schedule even if only bi-annually from their local householders.

Guide to Effective Waste Management

The best way of dealing with waste, both economically and environmentally, is to avoid creating it in the first place. For effective waste management, waste minimization, reuse, recycle and energy recovery are more sustainable than conventional landfill or dumpsite disposal technique.

Olusosun is the largest dumpsite in Nigeria

Waste Minimization

Waste minimization is the process of reducing the amount of waste produced by a person or a society. Waste minimization is about the way in which the products and services we all rely on are designed, made, bought and sold, used, consumed and disposed of.

Waste Reuse

Reuse means using an item more than once. This includes conventional reuse where the item is used again for the same function and new-life reuse where it is used for a new function. For example, concrete is a type of construction waste which can be recycled and used as a base for roads; inert material may be used as a layer that covers the dumped waste on landfill at the end of the day.

Waste Recycling

Recycling of waste involves reprocessing the particular waste materials, including e-waste, so that it can be used as raw materials in another process. This is also known as material recovery. A well-known process for recycling waste is composting, where biodegradable wastes are biologically decomposed leading to the formation of nutrient-rich compost.

Waste-to-Energy

As far as waste-to-energy is concerned, major processes involved are mass-burn incineration, RDF incineration, anaerobic digestion, gasification and pyrolysis. Gasification and pyrolysis involves super-heating of municipal solid waste in an oxygen-controlled environment to avoid combustion. The primary differences among them relate to heat source, oxygen level, and temperature, from as low as about 300°C for pyrolysis to as high as 11 000°C for plasma gasification. The residual gases like carbon dioxide, hydrogen, methane etc are released after a sophisticated gas cleaning mechanism.

MSW incineration produce significant amounts of a waste called bottom ash, of which about 40% must be landfilled. The remaining 60% can be further treated to separate metals, which are sold, from inert materials, which are often used as road base.

The above mentioned techniques are trending in many countries and region. As of 2014, Tokyo (Japan) has nineteen advanced and sophisticated waste incinerator plants making it one of the cleanest cities. From the legislature standpoint, the country has implemented strict emission parameters in incinerator plants and waste transportation.

The European Union also has a similar legislature framework as they too faced similar challenges with regards to waste management. Some of these policies include – maximizing recycling and re-use, reducing landfill, ensuring the guidelines are followed by the member states.

Singapore has also turned to converting household waste into clean fuel, which both reduced the volume going into landfills and produced electricity. Now its four waste-to-energy plants account for almost 3% of the country’s electricity needs, and recycling rates are at an all-time high of 60%. By comparison, the U.S. sent 53% of its solid waste to landfills in 2013, recycled only 34% of waste and converted 13% into electricity, according to the US Environmental Protection Agency.

Trends in Waste Collection

Since the municipal solid waste can be a mixture of all possible wastes and not just ones belonging to the same category and recommended process, recent advances in physical processes, sensors, and actuators used as well as control and autonomy related issues in the area of automated sorting and recycling of source-separated municipal solid waste.

Automated vacuum waste collection systems that are located underground are also actively used in various parts of the world like Abu Dhabi, Barcelona, Leon, Mecca and New York etc. The utilization of the subsurface space can provide the setting for the development of infrastructure which is capable of addressing in a more efficient manner the limitations of existing waste management schemes.

AI-based waste management systems can help in route optimization and waste disposal

This technique also minimizes operational costs, noise and provides more flexibility. There are various new innovations like IoT-enabled garbage cans, electric garbage trucks, waste sorting robots, eco dumpster and mechanisms etc are also being developed and deployed at various sites.

Conclusion

Waste management is a huge and ever growing industry that has to be analyzed and updated at every point based on the new emergence of threats and technology. With government educating the normal people and creating awareness among different sector of the society, setting sufficient budgets and assisting companies and facilities for planning, research and waste management processes can help to relax the issues to an extent if not eradicating it completely. These actions not only help in protecting environment, but also help in employment generation and boosting up the economy.