Environment

The final word on garbage

Why China wants to build world’s biggest rubbish incinerator

Plasma Arc incinerator technology could be solution says Husayn Anwar

When an economy is growing at 9% a year, you can be sure that garbage is also piling up at a startling rate.

This issue was in the news again last week when Nanfang Daily reported that Shenzhen plans to solve its own waste management problems by building the world’s largest incinerator.

Vice-mayor Lu Ruifeng announced the measure, saying that current landfills could no longer cope with the volume of rubbish produced by the city’s 13 million residents. The South China Morning Post added that the incinerator will be capable of processing 5,000 tonnes a day, in an effort to cope with the almost 5 million tonnes of domestic waste produced by the city each year.

Lu now has to struggle with one of the biggest challenges – where to locate the new facility.

In fact the topic of incinerators has been something of a hobby horse for WiC over the past couple of years. Truth be told, we haven’t been able to make up our minds about them.

In WiC48 we described the middle class protests in Guangdong’s Panyu district against a new incinerator plant. Homeowners were worried about the potential for dioxins, as well as the impact on local property values. There have been similar campaigns against planned incinerators in Beijing and other cities. But local governments still see them as a necessary solution to the waste disposal headache. In WiC5 we reported on Guangzhou’s intention to build a series of high-tech facilities that not only get rid of the rubbish, but produce energy in the process.

The new facility in Shenzhen – to be built by Singapore’s Keppel Seghers – is one of these newer generation waste-to-energy models.

Given the controversy, WiC has been in search of expert opinion. Husayn Anwar is an environmental specialist and entrepreneur who has lived in China for over 20 years.

Anwar founded and then sold Environomics (now ERM China), and later did the same with Sinosphere, before joining BP as a regional director to work on alternative energy projects in China.

He is currently managing partner of Verdaeon, which is focused on clean energy technology. Here’s Anwar’s take on China’s waste disposal problems and whether the latest incinerator technologies offer any solutions to the crisis.

Are Chinese cities facing a growing garbage crisis?

Yes, most Chinese cities are facing an increasing waste management challenge due to the rapid increase in personal wealth and consumption.

Also consumer goods are becoming more fancy, and as a result packaging is increasing significantly, which mostly translates into disposable waste.

Also non-degradable unrecycled goods are increasing as are hazardous and industrial wastes.

One disposal solution was landfill, but that seems to be running out in many metropolitan areas, right?

Yes.  Land near major metropolitan centres is at a premium, and the NIMBY [not in my backyard] phenomenon is common in China. So landfill space is very limited or very remote. In some cases landfilling may impact valuable ecological areas due to improper fill construction or management.

But incinerators are unpopular with those living near them. Why?

Several reasons.  Older Chinese technology was often unreliable and burned waste created a lot of hazardous and odorous emissions. Older imported technology is often improperly maintained or not operated according to specs. Thus waste is either not properly incinerated or has polluting emissions.

Despite government efforts, municipal, industrial, hazardous and medical waste get mixed and incinerated. But each of these categories needs to be incinerated at different temperatures and under specific conditions. Mixed waste is impossible to neutralise fully in any incinerator either due to temperature or volume requirements.

Generally even advanced technology, if not properly managed, will not be effective.  This is the most important shortfall in Chinese incineration.

Singapore’s Keppel Seghers is building the new incinerator in Shenzhen. What technology does it use?

Keppel has a multi-stage incineration system designed to convert heat generated from waste combustion to energy.  It meets all EU standards.  Again, as mentioned, the incinerator is very effective for processing conventional waste but may falter if industrial or hazardous wastes are combined in the incinerator feedstock or if the process is not managed properly.

What is the most advanced incinerator technology? Does it resolve concerns about pollutants?

There are various technologies but it is likely that Plasma Arc is the most effective in totally breaking down any type of waste. It produces such a high heat that it reduces any non-mineral waste to its elemental form (its gaseous phase).

Can you explain how it works?

High voltage current is passed between two electrodes creating an electrical arc. Inert gas under pressure is passed through the arc into a sealed container of waste material, reaching temperatures as high as 13,900°C. But the temperature around the torch can be as high as 2500–4400°C. At these temperatures, most organic wastes and complex molecules are broken into basic elemental components in the gaseous phase at a conversion rate of approximately 99%.

The non-organic wastes are then converted to vitrified slag.  The gas phase generated is syngas which can either be processed into chemical feedstock or used as fuel for power generation.

Where has it been used elsewhere?

Three companies seem to dominate the market: PEAT Energy (US), Plasco Energy (Canada) and Advanced Plasma Power (UK). There are existing facilities in Swindon and Ottawa, as well as in Taiwan (built by PEAT) and Japan (built by Hitachi Metals). A further 10 plants are under construction, including one in Beijing, built by Plasco Energy.

Is cost a stumbling block to widespread adoption in China?

Possibly. But while the initial capital costs are higher, operational costs are lower as the waste is converted to syngas which is used to generate energy for the process.

What do environmentalists think of the more advanced incinerators?

Plasma Arc technology is still controversial.  Proponents consider it a very attractive solution as it handles waste more effectively than more conventional treatment, and syngas is a useful end product for power generation or as chemical feed stock.

But environmentalists are still suspicious of the technology and the dangers of mismanagement in waste treatment – a very justifiable argument.

Despite what can go wrong, Plasma Arc is still a better solution.  Some argue that, like any other incineration type, it generates a lot of carbon dioxide.

But this cannot be avoided in any combustion process, unless some kind of capture-and-sink system is incorporated. It should also be noted, however, that landfills can generate a lot of methane gas, which is a much more potent greenhouse gas unless it is captured and used. This ultimately releases CO2 too.

From an environmental perspective, waste reduction and recycling should be the first step in waste minimisation.

But given the size of the population in China much waste is still being generated.  Therefore the solution needs to include maximising recovery and recycling while incinerating the remainder to generate power.  As waste in China has relatively higher water content, conventional incineration also requires much higher energy inputs. Plasma Arc may require less.

So Plasma Arc incinerators are the best options for Chinese cities?

There is no single ideal solution anywhere. Concepts of waste reduction through less packaging, recycling, recovery, reuse and composting at local levels must all be incorporated into the waste management solution.  However, even after all that, much waste is still going to remain. Plasma Arc is a very good option for dealing with that.


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