Why this website?
Welcome to The Truth about San Silvestre
The purpose of this site is to share key facts and information about the San Silvestre Environmental Technology Park in Barrancabermeja, Colombia. The park is an innovative waste management operation run by Veolia Aseo Santander since 2019, which only handles household waste.
Veolia has faced unfounded allegations of pollution affecting the Ciénaga San Silvestre wetland, located some 15 kilometers away from the park. These allegations are simply untrue.
This website is the truth about San Silvestre. It presents, in full transparency, all the technical and scientific elements in Veolia’s possession proving the absence of any link between the operations at the San Silvestre site and this alleged contamination.
Everything that we have published here is based on facts and supported by professional, objective and independent documentation. We stand behind every word.
Why is Veolia being targeted regarding waste management in Barrancabermeja? ?
Global Witness, an international NGO, alleges that Veolia Aseo Santander waste management operations at the San Silvestre Environmental Technology Park are linked to environmental and health issues in the Cienaga San Silvestre wetland, located 15 kilometers from the site.
These accusations were initially brought against Veolia for several months by a local NGO “Corporación San Silvestre Green” and more recently by Global Witness. The latter, supported by Open Society Foundations, is using these allegations as part of a campaign against the reform of EU regulation on sustainability due diligence.
Veolia vigorously rejects these allegations and has provided Global Witness with information and technical studies that unequivocally support this position.
The park’s leachate, a byproduct of domestic waste in landfills, does not contain measurable amounts of mercury. It is never discharged and remains within the park.
What they say about Veolia
Veolia has engaged with with all stakeholders, NGOs, and media on this subject in a transparent and sincere manner, ever since we were approached by Global Witness in 2023.
Media outlets such as Le Monde, BBC, The Guardian, El País, El Espectador and Caracol Noticias, have published reports that gather the opinions of various interest groups involved in the case.
Veolia has systematically responded to all requests from NGOs and media regarding the management of the site with complete transparency.
Global Witness was invited to visit the site on numerous occasions. To date, they have not accepted. Public and regulatory authorities, NGOs such as San Silvestre Green, and media such as The Guardian have visited the site.
The Colombian Environmental Authority has conducted three environmental audit visits in 2024. These monitoring visits are carried out by interdisciplinary teams of civil and environmental engineers, biologists, forestry engineers, chemists, geologists and other environmental professionals. The results of these visits certified the full compliance of the San Silvestre Park with the obligations established in the Environmental License (EIA and PMA), as well as its total environmental compliance, without irregularities, in the management of the operating basin, the mass of waste, the storm drainage and leachate management.
In March 2025, sampling was ordered by and conducted in the presence of the Environmental Authority, at sampling points used by Global Witness in 2024 to support its accusations against Veolia of mercury contamination of flora, fauna and local populations. Independent laboratory testing at those same sample points confirmed once again the absence of detectable levels of mercury.
What Veolia has said
Since 2019 – the year in which Veolia Aseo Santander took over the site – significant improvements have been made in the management and infrastructure of the Park, while continuing to focus on implementing best operational practices.
Veolia has consistently demonstrated the absence of any link between the site’s activity and alleged environmental pollution in the Cienaga San Silvestre, located 15 kilometers from the site.
Rigorous, independent testing has confirmed the absence of heavy metals in water and sediment samples. This is no surprise as the leachate, a byproduct of domestic waste in landfills, is treated within the park and does not contain detectable amounts of mercury.
This testing included samples taken in the same locations as NGOs Global Witness and San Silvestre Green, in the presence of the Colombian Environmental Authority.
None of the samples taken in 2024 by Global Witness present the characteristics of leachate contamination (e.g. high salinity).
About the type of services Veolia provides in Barrancabermeja
Veolia Santander collects the waste that residential users from local communities deliver in containers so that they can carry out the appropriate final disposal, in full compliance with Colombian environmental and technical regulations.
At the San Silvestre Environmental Technology Park, Veolia receives ordinary household or municipal solid waste, for which it has internal protocols and systematically refuses non-compliant waste.
The site does not handle hazardous waste.
About waste treatment
In a landfill, domestic waste produces leachate that requires treatment for certain parameters (e.g. levels of biological oxygen demand, chemical oxygen demand, conductivity, chlorides) to reach the environmental standard.
Leachate management is carried out 100% within the park, with a process that includes a biological treatment and reverse osmosis technology introduced in 2021, enabling the reuse of these treated liquids for internal irrigation activities, as authorised by the environmental authority. None of the processes lead leachate to water bodies. All operational activities and other works executed are carried out within the area licensed by the Colombian Environmental Authority, where in fact, wetlands are not located.
This leachate does not contain detectable amounts of mercury.
Samples from nationally certified laboratories demonstrate the leachate’s compliance with the maximum allowable limits under Colombian regulations.
About the reuse of wastewater
Following rigorous scientific evaluation, Veolia obtained a reuse permit for treated wastewater, to treat the leachates generated by a plant with reverse Osmosis Technology (Resolution DGL 000086 of March 5, 2021). The treatment eliminates enough pollutant load to allow reuse without causing any environmental impact.This reuse permit enables Veolia to use the treated leachate within the same Park for activities such as the irrigation of roads and internal meadows.
About mercury levels and other heavy metals
Analysis by an independent laboratory in 2024 and 2025 conclusively demonstrates that the San Silvestre Park cannot be the source of the alleged mercury contamination or any other heavy metal. The conclusion is based on rigorous scientific and technical tests, carried out in full compliance with the requirements of the operating permit.
Veolia has maintained two measuring points for groundwater monitoring and three points for surface water monitoring, both upstream (Moncholo Stream) and downstream of the San Silvestre Park.
The results show that mercury concentrations consistently remain below 0.001 mg/L, the regulatory threshold in Colombia for agricultural use.
No later than March 2025, sediment sampling was ordered by and conducted in the presence of the Colombian Environmental Authority, at sampling points used by Global Witness. Independent laboratory testing confirmed once again the absence of detectable levels of mercury.
In reality, Global Witness’ claims do not resist simple math. Given that mercury levels in leachate are below 0,001 mg/L, it would take a deliberate discharge of a volume equivalent to 115 years’ worth of site leachate production (or about 4.6 million cubic meters) for contamination by heavy metals at levels allegedly measured by Global Witness in sediment.
About the videos provided by the NGO Global Witness that allegedly show malpractices
Veolia has no information enabling it to verify the authenticity of these videos. Despite repeated requests to Global Witness, neither the date, nor the author, nor the context of these videos have been disclosed to Veolia. Veolia is also unable to identify the person appearing in this video. In any case, Veolia confirms that the discharge of untreated leachate into the waterways of the San Silvestre wetland is strictly prohibited and no instruction has been given in this regard. In accordance with the license it holds, Veolia Aseo Santander Y Cesar is only authorized to reuse the leachate after treatment using the reverse osmosis process at the San Silvestre site, without any discharge outside.
Veolia Aseo Santander Y Cesar suspects deliberate manipulation of the equipment aimed at damaging its reputation and a possible act of sabotage, and has filed a criminal complaint with the Prosecutor of the Nation, the competent local judicial authority.
Veolia has also reinforced security at the 30-hectare site with the installation of new security cameras and increased protection of onsite equipment.
Letter from the Chairman of Veolia to shareholders
Technical details San Silvestre
+ 60,000 tons
of solid waste managed per year220.000
residents served300
visitors per year300 tons
of organic waste processed through composting techniques per yearCertifications
Anti-Bribery Management System
Good Practices of Circular Economy
Occupational Health and Safety Management System
Environmental Management System
Quality Management System
The Untold Story of
San Silvestre
Testimonials
Latest news
- News
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19/01/2025
Commitment to decarbonization: Veolia Santander leads actions to combat climate change
20/05/2025
UDES and Veolia initiate their second phase of the “Sustainable Communities” project with greater environmental impact and new allies
8/04/2025
Veolia raised awareness in the Parque de la Vida community to prevent container theft and waste accumulation
27/03/2025
City Hall and Veolia intervened El Danubio to confront waste accumulation, with key support from the community
21/03/2025
The District City Hall joined Veolia’s initiative to commemorate International Women’s Day in the Patio Bonito village
15/03/2025
Waste management in Barrancabermeja: commitment, technology and environmental compliance
15/03/2025
Frequently Asked Questions
What does Veolia say about the pollution allegations?
Veolia maintains that the allegations are not true and that there is no credible evidence to back them up. The Environmental Authority, despite having visited the site multiple times, have found no evidence of the alleged contamination.
Veolia has consistently demonstrated the absence of any link between the site’s activity and alleged environmental pollution in the Cienaga San Silvestre, located 15 kilometers from the site.
Rigorous, independent testing has confirmed the absence of heavy metals in water and sediment samples. This is no surprise as the leachate is treated within the park and does not contain detectable amounts of mercury.
Samples were taken from locations downstream and upstream, including the same locations as NGOs Global Witness and San Silvestre Green, in the presence of the Environmental Authority.
When leachate contaminates water and soil, samples present certain chemical properties which are markers of this contamination. None of the samples taken by Global Witness present the characteristics of leachate contamination (e.g. high salinity).
Global Witness’ claims do not resist simple math. Given that mercury levels in leachate are below 0,001 mg/L, it would take a deliberate discharge of a volume equivalent to 115 years’ worth of site leachate production (or about 4.6 million cubic meters) for contamination by heavy metals at levels allegedly measured by Global Witness in sediment.
Regarding the alleged video evidence, Veolia has no information enabling it to verify the authenticity of these videos. Despite repeated requests to Global Witness, neither the date, nor the author, nor the context of these videos have been disclosed to Veolia. Veolia is also unable to identify the person appearing in this video. In any case, Veolia confirms that the discharge of untreated leachate into the waterways of the San Silvestre wetland is strictly prohibited and no instruction has been given in this regard.
Veolia Aseo Santander Y Cesar suspects deliberate manipulation aimed at damaging its reputation and a possible act of sabotage, and has filed a criminal complaint with the Prosecutor of the Nation, the competent local judicial authority.
The reality is that since taking over the landfill in 2019, Veolia has operated the site in compliance with environmental regulations, and provided scientific data to support this, repeatedly offering these organizations the opportunity to visit the site, and to date the invitation has been rejected.
Veolia continues to engage with NGOs on this issue, providing them with relevant data that shows that activities at San Silvestre since 2019 are not and cannot be the cause of the alleged environmental pollution.
Does Veolia have proof of environmental compliance at the San Silvestre Environmental Technology Park?
The San Silvestre Environmental Technology Park has certifications granted by the Colombian Institute of Technical Standards and Certification (ICONTEC):
- ISO 9001:2015 in Quality Management
- ISO 14001:2015 in Environmental Management
- ISO 45001:2018 in Occupational Health and Safety Management.
These certifications are proof of their comprehensive commitment to operational excellence, environmental responsibility, and employee well-being; thus, guaranteeing reliable and sustainable service for stakeholders.
Likewise, Veolia carries out rigorous environmental monitoring through periodic measurements and sampling conducted by an independent laboratory accredited by the Institute of Hydrology, Meteorology and Environmental Studies of the Ministry of the Environment (“IDEAM”), which cover the comprehensive analysis of all environmental parameters: water (surface and groundwater), air (air quality and emissions) and soil, which ensure compliance with all the parameters established for its operational license, in the current environmental regulations, and ensure the preservation of natural resources in its area of influence.
Additionally, all samples and tests carried out by the Colombian Environmental Authority have proven Veolia’s appropriate operational management of the site.
Veolia claimed that all landfill leachate is treated on site. How does the company explain the discrepancy between this claim and the video evidence presented by Global Witness?
Veolia has no information enabling it to verify the authenticity of these videos. Despite repeated requests to Global Witness, neither the date, nor the author, nor the context of these videos have been disclosed to Veolia. Veolia is also unable to identify the person appearing in this video. In any case, Veolia confirms that the discharge of untreated leachate into the waterways of the San Silvestre wetland is strictly prohibited and no instruction has been given in this regard. In accordance with the license it holds, Veolia Aseo Santander Y Cesar is only authorized to reuse the leachate after treatment using the reverse osmosis process at the San Silvestre site, without any discharge outside.
Veolia Aseo Santander Y Cesar suspects deliberate manipulation aimed at damaging its reputation and a possible act of sabotage, and has filed a criminal complaint with the Prosecutor of the Nation, the competent local judicial authority.
Veolia has also reinforced security at the 30-hectare site with the installation of new security cameras and increased protection of onsite equipment.
How does Veolia explain the alleged discrepancy with sampling done by Global Witness in September 2024?
Veolia conducts a series of sampling campaigns to monitor surface and groundwater, leachate, and soil, according to the locations and frequencies established by the Environmental Authority (CAS).
Global Witness claims that sediment samples, taken upstream of the park, allegedly register the presence of mercury and heavy metals.
This is inconsistent with the samples analysed both by Veolia and the Environmental Authority, through independent external laboratories, which were taken upstream and downstream of the park, and did not reveal any significant presence of mercury or heavy metals.
Global Witness has disputed both Veolia and the Environmental Authority’s sampling methods.
Contrary to Global Witness’ claims, there is no difference between the “sediment sampling method” of Lasertec, the laboratory commissioned by Global Witness on the 25th and 26th of September 2024 and the “soil sampling method” of Anascol, the laboratory commissioned by CAS on the 6th and 7th of March 2025.
The sampling methodology and locations are the same, as evidenced by a comparative reading of laboratory reports.
How does Veolia explain the alleged discrepancy with sampling done by Global Witness in September 2024?
Veolia conducts a series of sampling campaigns to monitor surface and groundwater, leachate, and soil, according to the locations and frequencies established by the Colombian Environmental Authority (CAS).
Global Witness claims that sediment samples, taken upstream of the park, allegedly register the presence of mercury and heavy metals. When leachate contaminates water and soil, samples present certain chemical properties which are markers of this contamination. None of the samples taken by Global Witness present the characteristics of leachate contamination (e.g. high salinity).
Global Witness’ claims are inconsistent with the samples analysed by Veolia on behalf of CAS, through an independent external laboratory, which were taken upstream and downstream of the park, and did not reveal any significant presence of mercury or heavy metals.
Global Witness has disputed both Veolia and the Colombian Environmental Authority’s sampling methods.
However, contrary to Global Witness’ claims, there is no difference between the “sediment sampling method” of Lasertec, the laboratory commissioned by Global Witness on the 25th and 26th of September 2024 and the “soil sampling method” of Anascol, the laboratory commissioned by Veolia on behalf of CAS on the 6th and 7th of March 2025.
The sampling methodology and locations are the same, as evidenced by a comparative reading of laboratory reports.
What does Veolia have to say about the claims made on social media in 2017 by Dr. Yesid Blanco, alleging a link between a previous landfill operation at San Silvestre and birth defects?
These claims are anterior to Veolia’s operations at San Silvestre and we are unable to comment. That said, to this date, official records do not show any such birth defects. Public health authorities, the environmental authorities, and the local prosecutor have found no evidence of any link between alleged pollution from the landfill and birth defects
Was Veolia management aware of alleged malpractice?
Veolia management has never authorised or instructed anyone to engage in the practices allegedly depicted. Veolia suspects an act of sabotage aimed at damaging its reputation and the good work of its employees.
Veolia operations fully comply with Colombian environmental regulations. The landfill does not spill or discharge leachate into water sources and that the handling and treatment of leachate is carried out 100% within the Park.
How does Veolia handle leachate on site?
At the San Silvestre Environmental Technology Park, leachate management is carried out 100% on site, using a process that includes biological treatment and reverse osmosis technology that allows -as a result- the reuse of these treated liquids for internal irrigation activities, as authorized by the environmental authority.
None of these processes bring leachate to water bodies, and all operational activities are carried out within the area authorized by the environmental authority, in which there are no wetlands and located more than 15 kilometers from Cienaga San Silvestre.
How does Veolia ensure compliance with environmental laws that local organizations and Global Witness claim it ignores?
Veolia Colombia operations in San Silvestre benefit from rigorous regulatory oversight and a corporate compliance policy that exceeds local regulations.
The Colombian Environmental Authority has conducted three audit visits during the last year, and that these follow-up visits are carried out by the Authority’s interdisciplinary team of professionals, composed of civil and environmental engineers, biologists, foresters, chemists, geologists and other professionals.
In addition, to keep its operating licence, Veolia must provide the environmental authority with regular reports about rainwater, surface, groundwater (upstream and downstream) and the leachate produced in the Park. This testing is carried out in an independent laboratory accredited by IDEAM quarterly, semi-annually, and annually.
What measures has Veolia implemented to ensure compliance with environmental standards and prevent pollution of water sources?
Veolia carries out rigorous environmental monitoring through periodic measurements and sampling conducted by an independent laboratory accredited by the Institute of Hydrology, Meteorology and Environmental Studies of the Ministry of the Environment (“IDEAM”), which cover the comprehensive analysis of all environmental parameters: water (surface and groundwater), air (air quality and emissions) and soil, which ensure compliance with all the parameters established in the current environmental regulations, and ensure the preservation of natural resources in its area of influence.
Veolia fully cooperates with Colombian regulatory authorities. The Colombian Environmental Authority has conducted three environmental audit visits during the last year. These monitoring visits are carried out by the interdisciplinary team of civil and environmental engineers, biologists, forestry engineers, chemists, geologists and other environmental professionals. The results of these visits certified the full compliance of the San Silvestre Park with the obligations established in the Environmental License (EIA and PMA), as well as its total environmental compliance, without irregularities, in the management of the operating basin, the mass of waste, the storm drainage and leachate management.
No later than March 2025, sampling was ordered by and conducted in the presence of the Colombian Environmental Authority, at sampling points used by Global Witness. Independent laboratory testing at these sample points confirmed once again the absence of detectable levels of mercury.
Veolia reiterates that the landfill does not discharge or release into the water sources. Management and treatment of leachate is carried out 100% within the Park.
There is no evidence that Veolia operations in San Silvestre are the cause of any pollution of the Ciénaga San Silvestre, located 15 kilometers from the park.
Does Veolia manage hazardous waste on site?
Veolia has consistently stated there is no final disposal of hazardous waste in San Silvestre. The site only receives ordinary domestic waste, mostly from residential users in the municipality of Barrancabermeja. This type of waste chemically cannot contain these types of substances in significant quantities and, therefore, there is no possibility of water source contamination by mercury, iron, and cyanide.
Ordinary solid waste generates leachate, but as it is reused within the Park, there are no discharges to the water sources. This is reflected in the Environmental Compliance Reports provided by Veolia to the environmental authority including numerous tests and sampling taken on site.
Can Veolia provide information on its interactions with local stakeholders and the community located near its operations?
Veolia is involved in many community outreach programs and ongoing social initiatives around San Silvestre:
- School for leaders: a program to train community leaders on environmental regulation. In the last year, Veolia has helped 72 presidents of the Communal Action strengthen their knowledge.
- Environmental Workshops: promoting knowledge and adequate management of waste. In the last year, Veolia has trained more than 3,000 people.
- Guided visits: more than 300 people annually visit San Silvestre Park.
- Around Ibero-America: It is an environmental awareness campaign for children. Veolia has welcomed more than 170 students from the local community schools, participating in the program’s 2024 edition.
- Environmental Guardians: educational program for children about caring for natural resources. Veolia has welcomed more than 250 students in the program.
How does Veolia intend to keep its corporate sustainability commitments in light of these allegations?
Veolia is committed to its corporate sustainability objectives, intensifying its monitoring and control program, to ensure rigorous supervision of environmental compliance. Each Veolia Colombia subsidiary complies with the environmental obligations prescribed in licenses and permits granted by the relevant authorities.
In addition, Veolia continues to engage with environmental authorities and local stakeholders to improve understanding of their Business Group’s sustainability commitments, reinforcing trust and transparency in their processes. It also highlights that despite the unfounded nature of these allegations, their dedication to environmental responsibility sets them apart in the sector, reaffirming that they are fully committed – both in Colombia and globally – to fulfill all legal and environmental obligations, which is a central aspect of their corporate policies and has earned them positive recognition worldwide.
The San Silvestre Environmental Technology Park has guided tours during specific seasons of the year to welcome individuals.
Enter your details in this form to know the schedule of visits.