WtE: the Redeemer of Brazil's waste legacy?

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In 2014 Brazil will host the FIFA World Cup followed by the Summer Olympic Games in 2016. As a result a huge amount of investment is being spent, yet waste management improvements still lack funds. Sergio Guerreiro Ribeiro explores the potential for waste to energy technologies to flourish in such a situation.

 

Antonio Carlos Jobim, the world famous Brazilian composer of Girl from Ipanema, used to describe our country with a joke: “Brazil is not for beginners”. This does not mean the level of expertise is so high that in order to succeed one must be very competent.

After 20 years of strong military rule with limited political freedom, the politicians took over and established a new kind of dictatorship, a ‘democratic’ one supported by a very slow legal system. Marketing, controlled by a few powerful people, assumed an importance never seen before, making no distinction between the truth and the lie. Very often laws dealing with new technologies are made by people without the necessary technical knowledge and in this scenario innovation and science have little space. Of course we all hope this situation will change but strong government propaganda is able to convince even highly educated people that Brazil is marching towards becoming the number one country in the world, despite the enormous gap in areas such as education, health, sanitation and waste management infrastructure.

Strong evidence of this can be seen in the new Brazilian policy on Solid Waste Management, law 12.305 signed by former President Lula on August 2, 2010 also known by its Portuguese abbreviation, PNRS. It took 20 years of discussions in Congress. And after trying to please many different lobbies, resulted in a very misleading piece of work containing mistakes that should be immediately corrected if it is to be taken seriously by society. A comparison with the directive 2008/98/EC of the European Parliament exposes the flaws in the policy.

Comparisons to Europe

Directive 2008/98/EC has one main objective, minimising ‘the negative effects of the generation and management of waste on human health and the environment. Waste policy should also aim at reducing the use of resources, and favour the practical application of the waste hierarchy’. However, Brazil’s PNRS has no less than 15 objectives, some of which difficult or impossible to implement. Also it does not present a clear hierarchy for waste management activities.

High MSW generation aside, Brazil is still one of the world leaders when it comes to aluminium can recycling, due to its small armies of waste pickers

Landfills are the last option in the European hierarchy, beneath energy recovery in high-efficiency facilities. But the Brazilian law, mistakenly, defines landfills as the ‘environmentally adequate’ solution, preventing the adoption of somewhat more expensive solutions, at least in the short term, despite superior environmental credentials.

Brazil’s waste management policy, which came to fruition after 20 years of discussion, includes a total of 15 objectives

Due to technical limititations it is not possible to economically recycle all combustible waste such as plastics, paper and others, except in waste to energy (WtE) facilities. Article 30 of the PRNS states ‘aims to reduce the waste of resources and environmental damages’. But this is exactly what landfill disposal of untreated waste is all about. Therefore the law contradicts itself. The new landfill in Rio de Janeiro (see diagram on page 39) in Seropedica, an area located 80km from downtown Rio, is being built over an important underground water reservoir. Yet the authorities claim it will be a milestone in waste disposal for the city and an example for the country.

The Brazilian PNRS gives the impression that recycling will increase sharply with the new regulation. However, recycling in Brazil is not low. Data from the Brazilian Association of Public Cleaning and Special Waste Companies (ABRELPE) shows this clearly, and it is well known that Brazil is a world leader in aluminium can recycling (98%) without any government interference. This is because most recycling is done by a great number of small groups of low income ‘waste pickers’, who make their living collecting recyclables before the municipality trucks. To improve the current situation, the law should regulate source separation with selective collection, but this implies new trucks and additional costs.

Waste to Energy in Brazil

Approximately 156 million people live in 5565 municipalities and the remainder of the nearly 200 million live in the countryside. The collection situation is far better than final disposal, since nearly 50% is dumped in inadequate landfills. On the other hand there are differences in the standard of living between the south and north regions. Some southern cities are approaching income levels witnessed in developed countries, at the same time realising that they must improve waste management accordingly.

For several years WtE has been discussed in Brazil with no practical results, since there are no commercial facilities under construction. This is despite the great number of feasibility studies going on. There are two main reasons for the current situation: few people in Brazil are familiar with WtE and the great advances achieved by the industry in developed countries. Furthermore, not many in the WtE industry care to understand the specific Brazilian conditions. They come with the solution looking for a problem. Some major facts that are constantly ignored when considering building a WtE plant in Brazil include:

  • Gate fees are very low, approximately $15-20/ton
  • High moisture waste with Lower Heating Value (LHV) under 8 MJ/Kg (3,439 Btu/lb)
  • High taxes on energy sales and waste management services approaching 20% of total gross income
  • For small and medium size facilities with gross annual income under $28 million, total taxes drop to less than 10% (this is a great advantage that should be explored)
  • For WtE plants with net generation less than 30 MWe transmission and distribution fees (wire usage) are zero if at least 50% of the energy come from the renewable fraction (Resolution ANEEL 271)
  • Natural gas prices are high > $9/MMBTU turning high efficiency combined cycle hybrid plants burning MSW and, large amounts of Natural Gas (NG) not attractive
  • High thermoelectric energy prices, around $88/MWhe (favours high efficiency plants)
  • Strong landfill lobby from large waste management companies
  • New Solid Waste Policy (PNRS) ‘accepts’ WtE but classifies ‘modern’ landfills as ‘environmentally adequate’ solution
  • WtE is relatively unknown therefore faces little opposition but this may change depending on how it is presented to the population
  • Major cities such as Rio de Janeiro, São Paulo and others are having problems finding sites at which to locate new landfills meaning that the waste is travelling great distances and costs are increased. Some landfill companies are beginning to realize they will not make money especially now that carbon credits are not a sure source of income
  • Hot tropical climate without the common European option of using waste energy for district heating
  • Interest rates are the highest in the world. Currently the basic interest rate dictated by Brazilian Federal Reserve is close to 12%. This implies investors demanding IRR higher than 15% unless they obtain financing from BNDES (Brazilian Bank for Economic and Social Development) at very low rates.

Although this may seem correct it introduces many distortions and sometimes prevents the adoption of a good technology or allows the use of bad solutions due to inadequate technical background by the bank officials.

Feasibility studies

To import a good solution that is working abroad may not be a straightforward task. Indeed, quick calculations show that a conventional WtE mass-burning facility (40 bar/400°C steam conditions), the most common worldwide, is not feasible in Brazil. Some companies with strong influence in government are trying to obtain incentives to make the spreadsheets look good. This may work in some places but will not prevail as a sustainable way to reduce landfills on a major basis. Also to consider unrealistic Operations and Maintenance (O&M) costs will lower the quality of flue gas, and other effluents, treatment which will bring a negative image to WtE.

Several feasibility studies in Brazil start with cost estimates based on a mass throughput (tonnes/day) but the key parameter for the investment and operating costs is the thermal output. With respect to energy recovery MSW is a mixture of dry combustible (Carbon and Hydrogen), water and inerts (ashes). The thermal output is directly proportional to the dry fuel amount (C and H), and which determines the size of the boiler, the flue-gas volume and therefore the size of the flue-gas cleaning devices.

Many people in Brazil advocate Mechanical Biological Treatment (MBT) to produce Refuse Derived Fuel (RDF) because of the high moisture waste. If the grate is well designed and able to burn all of the carbon and hydrogen in a mass-burning facility, and the moisture can be evaporated in the pre-combustion zone using adequate combustion air preheating, there is no need to pre-process waste (RDF) under the argument that more energy will be available.

Organic issues

One fundamental question that is causing controversy in Brazil is should the organics be removed from mixed waste? Singapore has many similarities with Brazil such as climate, waste characteristic with high moisture and reduced LHV. They recycle 57%, mass-burn 41% and send only 2% of inerts to Semakau landfill.

Despite the fact Singapore has one of the best source separation systems in the world, organics and non recyclables are incinerated together. On the other hand the per capita income in Brazil is much lower than in Singapore and some changes are needed to adopt WtE after recycling.

All of the above present positive and negative points since it is well known that corrosion with steam temperatures above 400°C limits the efficiency of WtE plants. Therefore, higher steam temperatures using only MSW will decrease the availability and/or increase capital and O&M costs due to corrosion related problems. Combined cycles (Zabalgarbi) will have high efficiency and high availability but the NG consumption is enormous (80% of the total energy produced comes from the NG) and it is hard to justify the environmental gains of WtE with such a high amount of a fossil fuel needed. Also the uncertainty in the NG supply and price will increase the risk of the enterprise in Brazil.

Using a standalone external superheater (Heringen) burns natural gas with 30% efficiency (limited by steam cycle) and the economic feasibility does not improve much over conventional WtE plants (40 bar/400°C).

A Brazilian solution

To improve feasibility in actual Brazilian conditions the Waste to Energy Research Technology Council (WTER) Brazil has developed and patented (WIPO No. WO/2010/057279); a modified type of combined cycle MSW/Natural gas, burning a very limited amount of natural gas (with 45% efficiency) and around 80% of the energy produced by MSW with efficiency around 34%. The “trick” is to use a small gas turbine (GT), just to supply the plant self-load, and increase the GT exhaust by mixing it with preheated air using the heat available after the external superheater. There are no stack losses in the GT exhaust circuit. Since the NG share is small it is possible, although not compulsory, to replace it with landfill gas, sewage biogas, ethanol, syngas from biomass gasification and/or other renewable fuels. The scheme does not demand any changes in the current incinerator technology and uses only standard components that already exist in other WtE plants.

The new landfill site in Rio, with a capacity of 9,000 TPD, will see waste travelling 80km so that plastics can be disposed and methane burnt to to obtain carbon credits

Forthcoming tenders

Companies such as Siemens, CNIM, Keppel-Seghers, VonRoll, Sener, Pöyry, Fisia-Babcock, Malcolm Pirnie and others are already established in Brazil, either with offices or doing partnerships to develop WtE projects in several cities: Belo Horizonte, Rio de Janeiro, São Paulo, São José dos Campos, São Bernardo do Campo and others. Soon there will be public tender requests for several municipalities in Brazil and the winning criteria must include minimum tipping fee to final waste disposal, low environment impact and consolidated technologies.

If the first modern WtE plant is built in Brazil, it’s a sure thing many others will follow. This will open a huge market to showcase developed WtE technology. What is not clear is why is it so difficult for this challenge to be accepted by the industry leaders?

Sergio Guerreiro Ribeiro is president of the Waste to Energy Research Technology Council (WTERT) Brazil
email: sergiog@wtert.com.br

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