By Gerardo Bernache Pérez
The integral management of waste leads to consider minimization as strong points, as well as separation for recycling. In other words, although it is currently required to build and operate safer final disposal sites, the long-term solution is not to build them bigger and with greater security, but to reduce the amount of waste we produce and establish separation programs to avoid that the waste is buried.
The most serious problem in waste management is final disposal. The common practice in all Mexican municipalities is to bury garbage in places that are not suitable due to the risk of contamination of water sources and the impact they can have on residents who live in neighboring areas and nearby properties.
Types of disposal sites
Garbage is buried in three types of disposal sites. The first is the open-air dump, a garbage dump. At this site there is no control of final disposal: anyone can come and dump their load of garbage there. Sometimes there is someone who charges a fee upon entry depending on the size of the load, but administrative and environmental controls are absent in the dumpsters. These sites regularly suffer from fires, as they are set on fire to reduce the volume of waste to ash and to be able to continue depositing more loads of rubbish. An open-air dump has no control over its disposal, nor over the pollution it causes in an entire region.
The second are municipal landfills, sites with an administrative control that restricts access and disposal on the site. They are located on municipally-owned land, have roads for heavy trucks, perimeter fence, entrance booth and surveillance. Generally, the landfills have an engineering planning for the use of the site by sectors, which are filled in trenches, cells or strata. Heavy machinery is used there to accommodate and compact the waste unloaded by trucks. Town hall collection trucks have identification that allows them to enter automatically. The other users have to register with the corresponding municipal authorities and pay an amount per disposal that is according to the weight in tons.
In the landfill there are some minimal controls on the soil contamination processes, but in most cases the capture and storage of the leachates that regularly escape from the property is not carried out properly.
Leachates are liquid runoff containing pathogenic microorganisms and other types of hazardous waste such as lead, hexevalent chromium, cadmium, nickel, and arsenic.
The decomposition of organic waste on site produces methane gas which freely escapes into the atmosphere or is intentionally released through ventilation pipes in order to avoid explosions.
Methane is a greenhouse gas and is massively produced in landfills. When landfills release methane, it contributes significantly to air pollution in Mexican cities.
The third type of disposal site is the sanitary landfill, a complex engineering work that requires a million-dollar investment and whose purpose is to confine the buried waste in such a way that the contamination vectors are under control within the site and receive treatment to neutralize them.
This is the ideal type of infrastructure for a final disposal of municipal waste. It is environmentally safe. However, even the most secure landfill is not a sustainable solution to the garbage problem.
The comprehensive management of waste leads to consider minimization as strengths, as well as separation for recycling. In other words, even though safer disposal sites are currently required to be built and operated, the long-term solution is not to build them larger and safer, but to reduce the amount of waste we produce and establish separation programs to avoid that the residues are buried.
Final waste disposal in Mexico
Mexico has 2 thousand 439 municipalities where city councils have the responsibility of waste management. It is estimated that of every 100 solid waste disposal sites in Mexico, about 66 are open-air dumps without any environmental control. Another 33 are municipal landfills with minimal technical and administrative controls, but with flaws in the infrastructure to control environmental contamination. Only one is a deposit with greater control and can be called a sanitary landfill. That is, two thirds of the final disposal sites are landfills and one third are municipal landfills. Thus, the percentage of landfills is minimal.
Open-air dumps are found in ranches, rural towns, small and medium cities where municipalities have scarce resources for garbage management. Municipal landfills are more common in cities with a population greater than 250,000 inhabitants, where local governments have a certain level of income and a stable budget exclusively for waste management.
Finally, the few sanitary landfills in the country are generally located in the main cities and metropolitan areas, which is why they manage to capture large volumes of municipal waste. It is estimated that 17 percent of the municipal waste generated daily throughout the republic goes to sites with greater control and sanitary landfills, that is, they have a good or very good final disposal, from an environmental point of view. The other 83 percent of the waste is deposited in sites whose infrastructure and operation can be classified in a range that goes from bad to terrible.
It is common for both municipalities and waste management companies to give the name of sanitary landfill to all types of landfills, which is incorrect. It is also true that those responsible for operating landfills give the name of "sanitary landfill" to a landfill to make it appear that it is an environmentally safe disposal site, even if it does not comply with environmental performance regulations.
The problem is when the serious figures and statistics reported by both INEGI and Semarnat fall into the game of the misrepresented concepts of "sanitary landfills" and report an exaggerated number of 88 sanitary landfills that supposedly operate in the country. Then, they also assume that two-thirds of municipal solid waste produced in Mexico is being confined to environmentally safe sites, which is far from the reality. If the operations of final disposal sites that have operations in the national territory are reviewed in detail, only 24 would be well evaluated.
Uncomfortable Neighbors: Landfills
Currently, the main risk caused by the contamination of garbage dumps and landfills is that an increasing population is settling in adjoining or nearby properties. Although there is a regulation that does not allow the installation of a final disposal site less than 500 meters from an inhabited area, there is no restriction on the construction of formal subdivisions and irregular settlements in the vicinity of a landfill. The construction of all types of housing on nearby properties is a growing phenomenon in large metropolitan areas, as well as in the main cities of the country.
At the beginning of the 1990s, in the metropolitan area of Guadalajara, human settlements near the dumps were few and small, in marginal colonies and irregular settlements with a high rate of poverty. The case of San Gaspar is one of the most important, since in this 30-hectare area there are five colonies that house some 1,500 inhabited homes. The construction of residential houses of various economic levels, mainly low and medium low, continues at a constant rate. The community affected by daily contact with the contamination of the dumps in San Gaspar is about 10,000 inhabitants.
The construction of the UrbiQuinta subdivision on a huge site adjacent to the Coyula landfill is an exceptional case due to the scale of the settlement. It is estimated that some 17 thousand families will live in the same number of houses that are being finished on a property of more than 500 hectares.
The lower part of the UrbiQuinta subdivision is located in the direction of the leachate and winds from the Coyula landfill. Leachates from the landfill run downhill, in some cases crossing parts of the UrbiQuinta property and in others following a course parallel to its perimeter on its way to the depths of the Santiago River ravine.
There are not only surface runoff here, but also underground runoff that outcrops hundreds of meters from the spillway.
In the municipality of El Salto there are a dozen colonies and in Tonalá at least two towns (Puente Grande and Tololotlán) that are being affected by the contamination that originates in the Los Laureles landfill. Agricultural production in this area ended due to the poisoning suffered by the water wells that were reached by the leaks of dangerous leachate. The cattle of farms dedicated to the production of milk, to the raising of cows and sheep were dying and the producers decided to close them and move elsewhere because they could not face the losses.
The population living in these colonies and towns has suffered firsthand the impact of pollution. Indeed, they cannot have the water from their wells and their health is affected by the inhalation of gases and the nauseating odors that are constantly dispersed towards their colonies and inside their houses. Also for powders laden with pulverized residue particles. Diseases of the skin, eyes, gastro-intestinal and others are reported by the inhabitants who live near the Los Laureles landfill.
More and more families live in properties near the landfills that are located in the Guadalajara metropolitan area. In the near future, this trend will increase and with it the risk to the health of the inhabitants of these colonies, who will be identified as contaminated communities due to their constant exposure to emissions of gases and dust, to waters poisoned with hazardous waste. It is a matter that requires urgent solution by the authorities.
Gerardo Bernache Pérez, CIESAS Occidente. The Ecological Day. Mexico