Tag Archives: Incineration

Guide to Effective Waste Management

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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.

Medical Waste Management in Developing Countries

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Healthcare sector is growing at a very rapid pace, which in turn has led to tremendous increase in the quantity of medical waste generation in developing countries, especially by hospitals, clinics and other healthcare establishments. The quantity of healthcare waste produced in a typical developing country depends on a wide range of factors and may range from 0.5 to 2.5 kg per bed per day.

medical-waste-management

For example, India generates as much as 500 tons of biomedical wastes every day while Saudi Arabia produces more than 80 tons of healthcare waste daily. The growing amount of medical wastes is posing significant public health and environmental challenges across the world. The situation is worsened by improper disposal methods, insufficient physical resources, and lack of research on medical waste management. The urgent need of the hour is to healthcare sustainable in the real sense of the word.

Hazards of Healthcare Wastes

The greatest risk to public health and environment is posed by infectious waste (or hazardous medical waste) which constitutes around 15 – 25 percent of total healthcare waste. Infectious wastes may include items that are contaminated with body fluids such as blood and blood products, used catheters and gloves, cultures and stocks of infectious agents, wound dressings, nappies, discarded diagnostic samples, swabs, bandages, disposal medical devices, contaminated laboratory animals etc.

Improper management of healthcare wastes from hospitals, clinics and other facilities in developing nations pose occupational and public health risks to patients, health workers, waste handlers, haulers and general public. It may also lead to contamination of air, water and soil which may affect all forms of life. In addition, if waste is not disposed of properly, ragpickers may collect disposable medical equipment (particularly syringes) and to resell these materials which may cause dangerous diseases.

In some countries, there may be legal remedies for such losses. For example, Floridians in the US can go to a medical malpractice lawyer in West Palm Beach. In others, especially developing countries, it may be harder to get compensated, and disease may be spread more easily as a result.

Inadequate healthcare waste management can cause environmental pollution, growth and multiplication of vectors like insects, rodents and worms and may lead to the transmission of dangerous diseases like typhoid, cholera, hepatitis and AIDS through injuries from syringes and needles contaminated with human.

In addition to public health risks associated with poor management of biomedical waste, healthcare wastes can have deleterious impacts on water bodies, air, soil as well as biodiversity. The situation is further complicated by harsh climatic conditions in many developing nations which makes disposal of medical waste more challenging.

healthcare-waste-india

The predominant medical waste management method in the developing world is either small-scale incineration or landfilling. However, the WHO policy paper of 2004 and the Stockholm Convention, has stressed the need to consider the risks associated with the incineration of healthcare waste in the form of particulate matter, heavy metals, acid gases, carbon monoxide, organic compounds, pathogens etc.

In addition, leachable organic compounds, like dioxins and heavy metals, are usually present in bottom ash residues. Due to these factors, many industrialized countries are phasing out healthcare incinerators and exploring technologies that do not produce any dioxins. Countries like United States, Ireland, Portugal, Canada and Germany have completely shut down or put a moratorium on medical waste incinerators.

Alternative Medical Waste Treatment Technologies

The alternative technologies for healthcare waste disposal are steam sterilization, advanced steam sterilization, microwave treatment, dry heat sterilization, alkaline hydrolysis, biological treatment and plasma gasification.

Steam sterilization is one of the most common alternative treatment method. Steam sterilization is done in closed chambers where both heat and pressure are applied over a period of time to destroy all microorganisms that may be present in healthcare waste before landfill disposal. Among alternative systems, autoclaving has the lowest capital costs and can be used to process up to 90% of medical waste, and are easily scaled to meet the needs of any medical organization.

Advanced autoclaves or advanced steam treatment technologies combine steam treatment with vacuuming, internal mixing or fragmentation, internal shredding, drying, and compaction thus leading to as much as 90% volume reduction. Advanced steam systems have higher capital costs than standard autoclaves of the same size. However, rigorous waste segregation is important in steam sterilization in order to exclude hazardous materials and chemicals from the waste stream.

Microwave treatment is a promising technology in which treatment occurs through the introduction of moist heat and steam generated by microwave energy. A typical microwave treatment system consists of a treatment chamber into which microwave energy is directed from a microwave generator. Microwave units generally have higher capital costs than autoclaves, and can be batch or semi-continuous.

Chemical processes use disinfectants, such as lime or peracetic acid, to treat waste. Alkaline hydrolysis is a unique type of chemical process that uses heated alkali to digest tissues, pathological waste, anatomical parts, or animal carcasses in heated stainless steel tanks. Biological processes, like composting and vermicomposting, can also be used to degrade organic matter in healthcare waste such as kitchen waste and placenta.

Plasma gasification is an emerging solution for sustainable management of healthcare waste. A plasma gasifier is an oxygen-starved reactor that is operated at the very high temperatures which results in the breakdown of wastes into hydrogen, carbon monoxide, water etc. The main product of a plasma gasification plant is energy-rich syngas which can be converted into heat, electricity and liquids fuels. Inorganic components in medical wastes, like metals and glass, get converted into a glassy aggregate.