Current State of Waste Management in Mexico City

Mexico City is the third most populated agglomeration in the world. Amongst megacities, Mexico City occupies second place on most waste generation, after the New York region. The city’s waste generation can be linked to the high consumption and use of resources, consequence of the rapid pace of life.

by Diana Fernanda Butron B.

Waste Management in Mexico City is carried by three different groups: public cleaning services, private companies, and informal workers. Informal workers referring to the ones that are not formally registered as employed by the government or private company and work independently. The public cleaning services collect and execute the final disposal of the public solid waste. Private companies do the same, but for businesses and industries. Informal workers perform manual separation of the municipal solid waste. In addition, privately hired street sweepers and municipal employees negotiate and coordinate their tasks with the purpose of complementing each other and to avoid overlapping. However, official reports of waste management report only the public cleaning services as the supplier of waste collection and management services, not recognizing private collaborations and negotiations[2].

A total of 13,149 tons of solid urban waste, 1.4 kg per habitant, is generated in the city every day [2]. According to the government report of 2019 the composition of this amount is as follows: residential 48.1%, businesses 25.67%, services 13.76%, diverse 5.16%, market center 4.26%, and controlled residues 3.05%. The lowest percentage corresponding to controlled residues meaning residues of special management coming from medical units, laboratories, land and air transportation, and readaptation centres [1].

From the total amount collected 32% is reutilized through different processes: 15% recycling, 11% composting and 6% for alternative fuels. This means that 68% of the waste goes directly to landfill [3].

Infrastructure

The infrastructure which Mexico City’s public sector relies on to manage their waste is formed by: 12 transfer stations, 3 sorting plants, 2 compacting plants, 7 composting plants, 6 final disposing sites and 1 biodigester [3].

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Source: Inventario de Residuos Sólidos de México 2019

For the recycling process the city counts on 2,800 collection trucks, of which, after a pre-selection process on the trucks, the amount collected adds up to around 1,400 tons per day. In addition, three recycling plants implement manual and mechanical sorting of waste, processing of 500 tons per day.

The 12 transfer stations receive 11,500 ton per day. From this transfer stations the solid waste is transported for further treatment or to the final disposal in landfills [1].

This year, 2021, a new Transfer Station and Selection Plant was inaugurated. This new plant in Azcapotzalco is the most modern of Latin America with a processing capacity of 1,000 tons per day of different types of solid waste. The plant includes a mechanic separation by type of residues: organic and inorganic waste, size, plastics, PET, aluminium, packaging, and others. After the mechanical separation, manual sorting of recyclables takes place. In addition, the plant is equipped with German technology consisting of automatic sprinklers that capture the odour particles during operation hours, a smart system of mist points to apply germicide and air freshener, and roofs designed to avoid residue dispersion and acoustic insulation preventing noise propagation. Moreover, what is distinctive of this transfer station is that it is also a sorting plant, meaning that the transport in between is no longer needed. This transfer station and sorting plant has the capacity of receiving 1,400 tons of waste per day, 400 thereof arrive previously separated as organic waste and are later transferred to the compost plant. The plant has provided great savings to the city by the sale of recyclables, avoiding transportation and minimizing the volume of final disposal. At the same time, it has generated 404 jobs [4].

Source: Estación de Transferencia y Planta de Selección Azcapotzalco – Secretaría de Obras y Servicios. Gobierno de la Ciudad de Mexico [5]

The production of compost with organic waste is staged in seven locations. One of them, "Bordo Poniente” operated under the Secretary of Works and Services, receives 97.85% of the organic waste and also generates the most compost (97.19%). This location used to be the main landfill of the city until 2011, when the landfill was closed and then became a compost plant [1]. This plant consists of 37 hectares and is receiving around 1,400 tons per day. The compost produced in all plants is used in urban green areas and for reforestation purposes [3].

The generation of alternative fuels is achieved with a process of compaction of the solid waste carried out in 2 plants. The compaction of high caloric material provides an alternative for fuel to be used in cement ovens [3]. The gas generated from the biodigester is destined to an electric generator and the burner of the plant. In 2019 from the 1,022 tons of waste received approximately 51,100 cubic meters of gas were generated [1].

Mexico City transports most of their waste to landfills which are located outside the city. One of these landfills, "La Perseverancia” produces electricity with biogas [3]. From Mexico City the nearest final disposal site is located at a distance 35 km, while the distance to the further disposal site is 115 km. From this transportation around 2,569 tons of CO2 eq is generated every year.

As mentioned before, Mexico City does not have final disposal sites in the city and solid residues are transported to surrounding states. Therefore, the city is obliged to pay a tipping fee to dispose of the residues. In 2019, the cost for disposal per ton to the landfills in the state of Mexico was $211.84 MXN (8.73€), and for the site located in the state of Morelos $183.91 MXN (€7.58). A total amount of 2,916,268 tons were destined to final disposal sites in the year 2019, meaning that the city spent more than 617 million pesos (25.4 million €) in tipping fees.

Additionally, Mexico City generates a large amount of residues from construction or demolition due to the growing population and urban development. Part of these residues is received in the Bordo Poniente Location at the IV stage. In this stage, the residues are processed with specialized machinery. After being processed the residues are reused as ground stabilizers, as sub-base, in roadways, and as fillers in final disposal sites (landfills) [1].

Existing Legislation

Some of the legislation existing in Mexico City is as follows:

General Law for Prevention and Integral Management of Residues issued in 2003 and reformed in 2018. The main objective is to improve the solid residue management. Liquid residue flow through the drains and sewers of the city. This law requires from states and municipalities to adapt and generate their own versions of this law it for the local management of the residues.

Law of Solid Residues from the Federal District (now Mexico City) issued in 2003 and reformed in 2017. Through time, this law went through changes and updates, the newest version includes new classifications for special waste. Furthermore, this law includes rules for both generators and handlers of hazardous waste.

The most recent addition to the legal frame is the Environmental Norm for the Federal District (now Mexico City), published in 2015, but effective in June 2017. This norm established new classification criteria for solid residue separation. According to this norm, residues should be classified in 5 categories: biodegradables, inorganic with recycling potential, inorganic with limited utilization, special management and voluminous residues and lastly hazardous waste.

According to this norm citizens should classify their waste following the first four categories. Trash collectors, dependent on municipal governments, will receive organic waste one day followed by inorganic waste the next [6]. Delegations are committed to give notice to the citizens of the days they will be collecting each of the first four categories of waste types [1]. Also, one day per week is designated to the recollection of special management and voluminous waste.

The generators of hazardous waste and the big solid residues producers (more than 50kg per day) must comply with other kind of regulations, which includes special plans for their management [5].

The government of Mexico City claims that with this separation recycling tasks will be easier, while assuring organic waste is converted to compost and recyclable material is reutilized to produce new products. Furthermore, the quantity and volume of waste arriving to landfills will decrease and consequently also the contamination generated [7].

Areas of Opportunity

Four main areas of opportunity have been identified for Mexico City’s current waste management: weak institution, compliance with regulations, lack of new infrastructure, and limited financial resources destined for the municipal solid waste management.

As mentioned before, there are three groups that perform the waste management services. However, the city´s government is not able to correctly direct and manage these groups to increase the amount of waste that is recycled.

When it comes legislation on waste, directed to those who do not carry out proper separation, enforcement of the regulations is not performed. This, in consequence, leads to poor participation of both the citizens and those who provide the service of sorting the urban solid waste.

In order to reduce the amount of waste arriving at landfills, an increase in the recycling rate must take place. Therefore, more efficient treatments, such as heat treatment could help with this endeavour. Waste incineration could be a sustainable option for waste that can’t be sent to organic treatment or recycled, from an environmental, economic, and social perspective. However, there is a strong opposition from the population and environmental groups to such treatments due to the lack of space and the proximity to the urban areas. This is one of the reasons why the municipal solid waste management has not grown or diversified.

In addition, a limited budget has led to municipal employees and volunteers asking for tips to provide services. The higher the tips and the more valuable the salvaged materials they receive, the better the service they provide. Authorities tolerate the workers and volunteers asking for tips as that money is spared and destined to the maintenance of garbage trucks. [2]

References

[1]   Secretaría del Medio Ambiente - Gobierno de la Ciudad de México, "Inventario de Residuos Sólidos de La ciudad De México 2019,” https://www.sedema.cdmx.gob.mx/storage/app/media/DGCPCA/InventarioDeResiduosSolidosDeLaCiudadDeMexico_2019.pdf.
[2]   F. Gutiérrez Galicia, A. L. Coria Páez, and R. Tejeida Padilla, "A Study and Factor Identification of Municipal Solid Waste Management in Mexico City,” Sustainability, vol. 11, no. 22, p. 6305, 2019.
[3]   Secretaría del Medio Ambiente - Gobierno de la Ciudad de México, "Manejo De Residuos Sólidos En La Ciudad De México,” https://www.obras.cdmx.gob.mx/storage/app/media/RSU/RSU%20CDMX%20.pdf.
[4]   Jefatura de Gobierno, Estación de Transferencia y Planta de Selección Azcapotzalco, la más moderna de América Latina: Sheinbaum Pardo, 25.07.2021.
[5]   Secretaría de Obras y Servicios – Gobierno de la Ciudad de México "Estación de Transferencia y Planta de Selección Azcapotzalco”. https://www.obras.cdmx.gob.mx/storage/app/media/00025%20julio%20planta/250721estacion-de-transferencia-y-planta-de-seleccion-azcvf-4.pdf
[6]   Coprocesamiento.org, Leyes mexicanas para el manejo de residuos, 21.05.2019.
[7]   Secretaría del Medio Ambiente, Norma Ambiental NADF-024-AMBT 2013 sobre Separación, Clasificación, Recolección Selectiva y Almacenamiento de los Residuos del Distrito Federal.

published: , 12|2021
Keywords: Mexico

Diana Fernanda Butron Ballesteros
WtERT Germany