Though plans for mega-incinerator on artificial island by Shek Kwu Chau in Hong Kong look a "done deal", still worth looking at alternatives.
Emerging technology; akin to incineration but molecules are more like blasted apart at very high temperatures.
Looks very good if read proponents' info. December 2009 issue of Scientific American listed among World Changing Ideas: 20 Ways to Build a Cleaner, Healthier, Smarter World, inc:
Trash is loaded with the energy trapped in its chemical bonds. Plasma gasification, a technology that has been in development for decades, could finally be ready to extract it.
In theory, the process is simple. Torches pass an electric current through a gas (often ordinary air) in a chamber to create a superheated plasma—an ionized gas with a temperature upward of 7,000 degrees Celsius, hotter than the surface of the sun. When this occurs naturally we call it lightning, and plasma gasification is literally lightning in a bottle: the plasma’s tremendous heat dissociates the molecular bonds of any garbage placed inside the chamber, converting organic compounds into syngas (a combination of carbon monoxide and hydrogen) and trapping everything else in an inert vitreous solid called slag. The syngas can be used as fuel in a turbine to generate electricity. It can also be used to create ethanol, methanol and biodiesel. The slag can be processed into materials suitable for use in construction.
In practice, the gasification idea has been unable to compete economically with traditional municipal waste processing. But the maturing technology has been coming down in cost, while energy prices have been on the rise.
Page here covers some known or potential drawbacks:
- reasons against it include that doesn't work well with wet feedstock; and especially seem more philosophical, opposed to destroying waste and not making, say, compost.
Plasco’s demonstration plasma arc plant in Ottawa, Canada has been plagued with operational problems from the start in 2008, and has been unable to run at full capacity. On many occasions, emissions exceeded the maximum operational limit.
For the Ottawa project, Plasco had a “great deal of publicity” in the days leading up to a public meeting on the project, but not one person objected, he said.
While from Plasco's own website, Our Technology:
Plasco employs a patented process using plasma arc technology for the conversion of waste material into synthetic gas and marketable products. Plasco efficiently recycles heat from the process to gasify the waste and then uses the unique characteristics of plasma to refine the gaseous products into a clean, consistent syngas.
The quality of the fuel gas is highly controlled and consistent, producing fuel for a combined-cycle power plant (internal combustion engines plus heat recovery steam generators). The process also yields other valuable co-products including recyclable metal, construction aggregate, and potable quality water.
Solena Group employs plasma arc technology in several ways, including to even produce jet fuel:
Solena Fuels proprietary “biomass-to-liquids” (BTL) solution encompasses three major processing blocks. The first is Solena’s proprietary high temperature, single phase gasification technology which has the ability to process heterogeneous waste feedstock with the highest efficiencies in the industry. This process produces a clean, bio-based synthetic gas (“BioSynGas”) that is then conditioned and fed into a Fischer-Tropsch (“FT”) reactor. This second FT processing block transforms the BioSynGas into renewable forms of hydrocarbons such as light FT liquids and FT wax. The third block is the upgrading of the light FT liquids and FT wax into certified, sustainable jet or marine fuel. Our design also utilizes heat and tail gases to produce electricity. Solena Fuels’ reference BTL design processes approximately 500,000 tonnes of feedstock into 16 million gallons of sustainable fuel, nine million gallons of naptha and 20MW net of exportable electricity. These offtakes are in addition to the facility producing all of its own energy to operate the facility.
- Solena has proposed building facilities here, with Cathay Pacific interested in buying the jet fuel.
Advanced Plasma Power is a UK company using plasma arc technology to create syngas for creating power or biogas. See this image, with measurements of three organic compounds, before and after gas zapped by heat and UV light at plasma arc:
Some contact made with APP, which is interested in building facilities for Hong Kong.
Westinghouse Plasma Corporation makes plasma arc units; recent orders include a unit to process 950 tonnes of waste per day, for a waste to energy plant at Tees Valley, UK.
Anaerobic digestion is the horribly unsexy term for taking organic matter such as food waste, processing with bacteria, and creating methane and other biogas, plus compost.
Excellent technique, akin to traditional ways of making compost. There were plans to make extensive use of this in Hong Kong, but so far little more than a small plant or two: apparent drawbacks include lack of local demand for compost, plus need for good waste separation. But in some places, anaerobic digestion is highly important in waste treatment, such as:
Toronto - where the Green Bin Program takes organic waste, and turns it into compost.
Greater Manchester - where waste will be separated, with organic matter treated by anaerobic digestion to produce gas for power generation, and create refuse derived fuel that can also be used for power generation.
This must be the gold standard to aim for: no waste to landfill, or to incinerate (or destroy in plasma arc facilities). Can include anaerobic digestion, but also plenty of recycling, along with reuse and - of course - reduction so there isn't much thrown away in the first place.
San Francisco had made strong progress with zero waste:
Imagine a world in which nothing goes to the landfills or incinerators. We think it's achievable, and SF Environment is doing everything we can to make it happen... Today, San Francisco recovers 77 percent of the materials it discards, bringing the city ever closer to our goal of zero waste by 2020.
While we are well on our way to our diversion goals, ultimately we will need to look beyond recycling and composting to get to Zero Waste. This includes passing legislation to increase producer and consumer responsibility. In other words, manufacturers, businesses and individuals will need to be accountable for the environmental impact of the products they produce and use. There are a lot of ideas incorporated in the idea of Zero Waste.
Sadly, zero waste looks far too sophisticated for the Hong Kong government, which looks to be seeking a rather simple-minded solution to waste - aiming to make thousands of tonnes per day "disappear". But, maybe for the future, someday...
Zero Waste Alliance looks worth checking out; and even joining (open to individuals too), providing you agree with:
Working toward a world without waste through public education and practical application of Zero Waste principles.
- Convert waste to resources for the benefits of local production and the creation of a sustainable society.
- Redesign products and methods of production to eliminate waste by mimicking natural processes and closed-loops
- Resist incineration and land filling in order to promote innovation in resource conservation and methods of production
- Collaborate with others with common interests worldwide
See also an article from the UK: Alternatives to Incineration.