Edition 40, Marketing

Sanitary Landfills, or How to Become a Millionaire

By: Carlos Mondragón and Jimena Cabral

Wherever there are people, there will be problems with the generation of solid waste and residue; in other words, trash. Trash is natural or industrialized waste that when commingled produces unpleasant odor, generates bacteria harmful to the community, and loses its capacity for reuse or recycling. In modern society, many products are discarded when they break or no longer work because they have served their purpose. Most temporary-use products end up as solid waste. But much of the waste generated in households and industry can avoid becoming trash, because if it is correctly separated, it can be reused or recycled (in other words, it could fulfill other important functions). Furthermore, waste separation can be a significant source of revenue.

For many years, to get rid of trash we simply dumped it outside the cities. In these trash dumps, the waste was burned to reduce its volume. Over time, however, improvements were introduced, with techniques like: 1) sanitary landfills, 2) controlled incineration, 3) shutdown and cleanup of sanitary landfills, 4) preparation of compost, and 5) recycling.

In 2010, developed countries recycled between 35% and 60% of the waste they generated, while Mexico this figure barely reached 12%. In 2011, only 60% of the waste was deposited in sanitary landfills, while the remaining 40% went to trash dumps that failed to meet official standards.

Germans are leaders in trash separation, and for years now, they systematically separate glass from the rest and deposit paper and cardboard into special containers. They also have special deposits for discarding polyethylene containers, cans, organic waste and conventional trash. This is a result of a long process of making the population aware of the importance of separating waste. In consequence, German society is organized into blocks of housing that have containers for different types of trash. The cost to a community of collecting the trash depends on the volume they produce; therefore, the community that separates more waste pays less to have it collected. In 2010, Germany’s trash could be divided as follows: sanitary landfills, 20%; recycling and composting, 57%; and energy generation, 23%.

Holland is another outstanding example, because in 2010 it deposited only 3% of its trash in sanitary landfills. It separated 64% out for recycling and composting and 33% for energy generation. On average, only 27% of all the trash of Western European countries went to sanitary landfills, while 45% went for recycling and composting and 28% for energy generation. As of 2011, there were no reports in Mexico on the use of trash to generate energy.

Waste management in Mexico City

The Bordo Poniente trash tip covers 680 hectares and is located approximately 5 kilometers northwest of the Mexico City international Airport. Between 1970 and 1986 it was used as an open-air dump by the Venustiano Carranza and Gustavo A. Madero delegations, the latter of which gave it its name: GAM. The Bordo Poniente dump was divided into four phases, and as each one was filled, it was closed and prepared for cleanup (table 1). In 1985, it received more rubble from the devastating earthquakes of that year than any other dump in the city. The GAM trash tip was then turned over by the Mexico City government to the National Water Council. At the end of 2008, phases I, II and III had been reclaimed; phase IV should have been reclaimed by the end of 2009, but was delayed by two years. Each phase is successively reclaimed by containing the waste and converting the space into a zone with reduced environmental impact, managing the biogas (gas produced by the fermentation of waste) and leachates (oils and acids that filter out of compacted waste), growing grassy lawns and woodlands, and creating a treated-water lagoon.

The Mexico City government created a comprehensive recycling and energy center to separate and industrialize waste, but it is overwhelmed by the 12,000 metric tons of trash generated each day in the nation’s capital. Tremendous effort is being made to separate out organic waste and produce compost to restore the quality of the city soil.

In February 2012, another four sanitary landfills were opened in Mexico State, located in Ixtapaluca, Cuautitlán, Xonacatlán and Tecamac. Before reaching the sanitary landfills, trash is separated into organic and non-organic material at transfer stations. The organic material goes to make compost that will be used to regenerate green areas like parks and gardens. An attempt is also being made to produce biogas with the compost. Among the solid non-organic waste are materials that could be profitable, like paper, cardboard, aluminum, iron, copper, glass, rags, polyethylene containers, tires, cotton, rubber, leather, wood, ceramic, and electronic products. The non-organic material is bundled, and depending on their size and weight, the bundles are sent to various industrial centers for reuse. Tires are used for fuel in blast furnaces, because they can produce temperatures of up to 600°C without contaminating the atmosphere.

In Mexico City, these efforts have succeeded in separating out approximately 45% of the organic waste generated, equivalent to 4,800 metric tons, only 2,500 of which are used for compost.

Separated Trash is Money

The big trash generators today are households, which make up 47% of the total. They are followed by retail establishments (primarily stores and restaurants) with 29%; and finally, by services (hospitals, offices, schools and companies) with 24%. Most of the waste is organic, accounting for 43% the total. Mexico City’s sprawling Central de Abasto–where fresh produce comes in from around the nation to be distributed and sold in the city–generates 400 metric tons of organic material per day, equivalent to 20% of the total waste.

The materials most prevalent in non-organic waste are plastic (13%), cardboard and paper (11%) toilet paper, feminine napkins, and diapers (10%) and others (table 2).

Among the most valuable non-organic waste materials are copper, aluminum, cardboard and newsprint. Households, companies and schools would be surprised to learn how much money they could make a year if they were to separate out their waste and sell it in collection centers.

Until January 2012, this profitable business was taken up by the drivers of garbage trucks, as well as their assistants and informally-employed trash pickers who sift through trash at the dumps and sort out still-usable components.

It is important for Mexicans to become aware of the importance of separating trash. In addition to the economic benefits, it is better for public health and hygiene and can substantially improve the environment. The inhabitants of Mexico City can separate trash at home and at work into two or three containers, one for organic waste, another for non-organic waste and another–if they were convinced about sanitary waste–for used toilet paper and, in another bag within that container, discarded diapers and sanitary napkins. Batteries should be kept in a closed glass container, and when it is full, given to the trash collectors. If left in the open air, batteries are highly contaminating and hazardous, both for the environment and for health.

Trash can also be a source of renewable energy, because organic waste can generate biogas and digestate for generating electrical energy. Composting can significantly reduce the emission of greenhouse gases.

Table 3 shows some examples of the kind of revenues that can be obtained from separated waste. Separated waste is money; co-mingled waste is a source of contamination.♦

References

Department of Urban Improvement Programs. DGSU Office of Statistics and Information, Manejo de Residuos sólidos en la Ciudad de México (2011).

Enger, Eldon and Bradley Smith (2008). Environmental Science. A Study of Interrelationships, 11a. ed., Boston, McGraw-Hill.

Alejandro Ramos, La Jornada, 13 May 2010.

Jesús García, Reforma, 23 March 2008.

Tovar, L. Raúl, M. Teresa Orta and Gerardo Saucedo (2012), Composición y generación de residuos sólidos urbanos de la ciudad de México durante 2008 – 2009., Incluye los generados en la Central de Abasto del D.F. (in publication).

Table 1. Phases at Bordo Poniente

Table 2. Breakdown of solid waste in Mexico City (2009)

Tovar, L. Raúl, M. Teresa Orta and Gerardo Saucedo (2012), Composición y generación de residuos sólidos urbanos de la ciudad de México durante 2008 – 2009., Incluye los generados en la Central de Abasto del D.F. (in publication).

Table 3. Sale of waste for metric ton

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