GETTING RID OF WASTE MOUNTAINS

It grows and grows – the mountain of human-made waste. Denmark alone produces around 14 million tons of waste annually, corresponding to approximately 2.5 tons per head of population. And the figure is increasing in line with economic growth.

Nevertheless, it is the cleanness, tidiness and lack of waste dumps across the entire country which often makes the greatest impression on foreign visitors. That is because of what is called “The Danish Model” in international waste management.

“The Danish Model” is a unified waste system where municipalities are required to handle all waste from both households and industry, including dangerous waste. It is carried out through either large, shared municipality companies, or through private sector companies that specialise in collecting household and industrial waste as well as recycling.

The system operates with a high degree of waste sorting which is necessary for a high degree of waste incineration and recycling.

Denmark was the first country in the world to introduce a ban on depositing organic waste and waste suitable for incineration. The ban has increased waste incineration dramatically, at the same time as energy exploitation has been increased in connection with the conversion to heat and power production in the waste incineration plants.

“The Danish Model” is also based on a finely-meshed matrix of financial controls, where taxes and fees help to ensure that as few resources as possible are lost, and as much as possible is recycled or exploited for heat and energy.

 
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STOPPING HAZARDOUS WASTE

HAZARDOUS WASTE: Hazardous waste is still being dumped in many places around the world, where large stocks of pesticides represent a potential toxic bombshell. The Danish way of handling hazardous waste is setting a new standard in many countries.

In the old days, pesticides for the agricultural sector were produced independently of any relationship between consumption and demand. When an agricultural collective had pesticides delivered, in many cases the pesticides were just put into stockrooms – stockrooms which today represent a huge source of pollution to groundwater and a direct danger for the local population.

So says project manager Michael Hansen of the Danish consulting engineering company Niras, which is among the world leaders in managing and disposing of hazardous waste.

Toxic bombshell

“There is no doubt that old stocks of pesticides are one of the world’s largest problems regarding hazardous waste,” says Michael Hansen. “There are huge amounts lying around worldwide, in rusty old drums that leak directly into the groundwater. They are toxic bombshells, which fortunately are now being taken care of in many places.”

Niras’ department for hazardous waste management is based on Chemcontrol, previously a subsidiary of Kommune kemi, a shared facility for hazardous waste management owned by the Danish municipalities. Kommunekemi was among the first large facilities in the world especially intended for safe management of hazardous waste. It originated directly from Danish waste legislation, which has been a model for waste policies in many countries around the world. Niras acquired Chemcontrol three years ago, and the company is today involved in hazardous waste projects worldwide.

Designing Malaysia’s first waste combustion plant

“We provide assistance from consultancy on waste legislation and preparation of feasibility studies to implementation of legislation,” says Michael Hansen. “We often face highly complex problems, often with many different interests that need to be considered. But most authorities are fortunately realising that something

needs to be done. The days when hazardous waste was just dumped randomly and a blind eye turned to it, are coming to an end.” One of the most successful projects Niras has been involved in is in Malaysia, where Danish funding for developing countries (DANCED) in the 1990s was used to assist the start-up of a plant for disposal of hazardous industrial waste. Niras designed the first combustion plant and subsequently supervised the construction of the facility. In addition, Niras carried out significant training of staff which lifted their technical competences to a high level in a relatively short time. Today, the plant treats more than 80,000 tons of hazardous waste annually. Because of its success, Kualiti Alam Sdn Bhd, the company behind the waste treatment centre, has given Niras a new contract to design a new, combustion plant for treating all types of combustible hazardous waste, including chemical waste and hospital waste.

CLEAN CUSTOMMADE WATER FOR THE WHOLE WORLD

WATER TREATMENT: Clean water can mean many things. It covers a vast number of variations depending on where the water comes from, how it is treated and what it will be used for.

Denmark’s Silhorko-Eurowater A/S is one Europe’s leading manufacturers of water treatment plants for drinking water and process water in industrial companies. The company can supply exactly the water quality that is needed in the individual case. From ordinary drinking water with salts and minerals, to water for boilers or turbines where salts and minerals are completely or partly removed, to ultra-pure water for production in clean-room environments.

“Almost all industrial companies use water in one form or another as part of their operations,” says Torben Buhl, director of Silhorko-Eurowater. “Feed water for boiler plants, water for analysis purposes in laboratories, water for rinsing items in production prior to surface treatment, water for cooling, water for the production of beer, soft drinks and spirits. These are just some of the multiple tasks we encounter as a water treatment specialist.”

Increasing demands on water quality

For more than 70 years, Silhorko-Eurowater A/S has built up competences in water treatment for many different industrial applications, using a wide range of technologies based on filtration, membrane filtration and ion exchange.

“There are many reasons why industry requires special water, but the short answer is that there are constantly increasing demands on the quality of products, while production processes are becoming further automated and more high-tech – which means that production equipment is becoming more sensitive – which again makes higher demands on process water,” says Torben Buhl. “At the same time, industry is trying to optimise processes and reduce the environmental impact of production through for example reuse of water.”

Rapid local solutions

Today the company, best known outside Denmark as Eurowater, supplies water treatment plants worldwide. Since the composition of water depends on the source –ground water, lake or river – and varies considerably depending on local conditions – Eurowater carries out customers’ water treatment tasks as close to their geographical location as possible. As a result, the company has 40 representations in 25 countries, either through its own offices or through local collaboration partners.

“Closeness to our customers is of the greatest importance to us – because we know how important it is to them that we provide quick solutions. Operational reliability and rapid solutions to our customers’ continuous operation and optimisation tasks in water treatment are essential for such an important resource as water in a modern company,” says Torben Buhl.

http://www.eurowater.com

FROM WASTE TO ENERGY

INCINERATION: If the world is to avoid drowning in waste, it either needs to be reused or exploited for energy. In Denmark, combustion of waste is obligatory, and that has given Danish companies a technological lead in efficient and environmentally friendly waste combustion

Inconel welded directly onto the tubes

If waste can be reused, then it must be reused. If it cannot be reused, but can be combusted, it must be combusted. For many years these have been the central principles of the Danish waste model, which has now also been implemented at European level via an EU directive. This is not just to reduce the waste mountains, which in some parts of the world are engulfing entire cities and regions, but also to squeeze as much energy as possible out of the waste.

30 tons per hour

Even before Denmark made waste combustion obligatory – it was the first country in the world to do so – a Danish company had built up substantial expertise and technological know-how in the area. With a heat exploitation of more than 90% and simultaneous electricity production of almost 30%, combustion plants from Babcock & Wilcox Vølund are among the world’s best.

“Way back in 1931, we built the first waste combustion plant, and since 1934 we have exported plants to the entire world,” says sales director Kenneth Jørgensen, Babcock & Wilcox Vølund. “It has added up to more than 500 plants, of combustion capacities ranging from 10 tons per hour to more than 30 tons an hour.”

Grates that dry wet waste

Babcock & Wilcox Vølund’s core competence lies in the design of the grates on which the waste lands when it is fed into the furnace. This is a crucial area, because the ability of the grates to distribute and dry the often very wet waste is of critical importance to the combustion itself. Other important areas where the company has considerable expertise is in the design and construction of the combustion boiler.

“The parameters for quality in a combustion plant are energy efficiency for both heat and electricity, the ability to combust as much waste as possible with the least possible residual ash, environmental friendliness with as little emission as possible after flue gas scrubbing, and a low maintenance requirement,” says Kenneth Jørgensen.

Technologically advanced welding technique

Over the years, Babcock & Wilcox Vølund has developed and improved the technology that is used in the waste combustion plants. One of the company’s technical innovations is lining the boiler tubes with Inconel, an extremely resistant metal with a high content of nickel. Previously the boiler tubes that conduct steam to the electricity turbines were protected by a fire resistant material, but ceramic materials are very exposed and can cause many operational shut-downs and expensive service checks. With the new technique of welding Inconel directly onto the tubes, it is only necessary to carry out a service every fifth year.

“We are among the few in the sector who have mastered the special welding technique required with Inconel,” says Kenneth Jørgensen. “It probably makes us more expensive than our competitors, but then there is less maintenance which makes our plants far more efficient.”

http://www.volund.dk

 
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