Generales

By Carlos Olimpo Restrepo S, Journalist

At Universidad de Antioquia, different research projects are being carried out to take advantage of organic waste and, in this way, reduce contamination due to uncontrolled disposal in landfills or in open environments. The Interdisciplinary Group of Molecular Studies (Giem) is developing a project involving diverse plant and animal wastes to generate fertilizers and gas.

The research carried out by the Interdisciplinary Group of Molecular Studies uses different types of organic waste to obtain different types of fertilizers. Photo credit: Communications Office / Alejandra Uribe

If you have a laying hen, she can produce one egg per day, which can weigh between 60 and 70 grams. Additionally, it will generate between 100 and 120 grams of manure per day. Now, imagine this scenario on a larger scale, not in a small farmyard but on a poultry farm where there are hundreds or even thousands of birds, resulting in a huge amount of organic waste.

In recent years, these wastes were commonly discarded without proper treatment, often ending up in landfills or dispersed on specific crops, primarily due to their high nutritional value despite potential adverse effects. However, today, thanks to the research carried out since 1992 by Giem at UdeA, this and other organic wastes from animals and plants are being repurposed with increased efficiency. They are now utilized as fertilizers and soil enhancers without causing contamination. Additionally, these waste materials can even serve as energy generators.

Carlos Andrés Uribe, a researcher at Giem and lecturer in Industrial Engineering and at the University's Institute of Chemistry, has shown interest not only in chicken manure but also manure from pigs, cattle, and other domestic species, as well as vegetable crop residues, pruning discards and similar materials.
According to this doctoral candidate, “Transformation techniques are needed to produce a stabilized product. When applied to the soil, it should provide nutrients, organic matter, and contribute to soil health without carrying pathogens associated with raw materials.”

The demand for fertilizers, added to the idea of maximizing waste utilization and reducing organic pollution, led him to work in parallel on the generation of energy from the biogas produced by these discards.

Uribe said, “We developed systems to take advantage of different sources of residual biomass. One such system is known as Organic Fraction of Urban Solid Waste (Forsu), which is constantly produced in environments with collection services and has been implemented in most of the country's municipalities. In addition, there is a regulatory inclination to capitalize on this waste type, creating favorable conditions for the viability of these systems.” This legislative trend in Colombia is reflected in several laws, decrees and resolutions of the Ministry of Environment and Sustainable Development, addressing the ultimate disposal of different waste types.

He emphasized that, in this context, Giem is promoting a technological change based on scientific research. “We are developing reaction systems that facilitate the transformation of these residual flows into fertilizers, inputs for the chemical industry, and electrical and mechanical energy.”

In this regard, Carlos Alberto Peláez Jaramillo, founder of Giem and professor at the Institute of Chemistry, emphasized, "This work is basically a conceptual and experimental framework on a significant scale of what we know as biorefinery. This concept is inspired by oil refineries, where a series of co-products are generated from a raw material, all with an added value and intended for diverse applications or uses". 

Carlos Andrés Uribe's research project has transcended the laboratory phase and undergone large-scale testing in municipal plants. Collaborations with cleaning, poultry, pig, and cattle companies have been established. Furthermore, an energy-generating plant based on biogas was successfully installed in the east of Antioquia. The biogas is derived from the waste to illuminate a local road with LED lights.

For this research, Giem has fertilizer projects utilizing urban waste in several municipalities, including El Carmen de Viboral (processing 12 tons/month), El Peñol (7 tons/month), Támesis (60 tons/month), and Caramanta (2.5 to 3 tons/month).

The two main developments

Carlos Andrés Uribe emphasized that when he started his PhD research, he tried not to base his work on what had been done in other countries. His approach aimed to derive solutions better suited to local conditions.

“We did not have the resources to replicate models with 20 or more engines, as in waste plants in Germany, to generate energy, nor to support a large workforce. Therefore, the most appropriate thing to do was to use gravity. We developed a system with minimal machinery, lower energy consumption, and, in addition, we imposed restrictions to minimize processes conducted in the wet phase of these wastes to prevent water pollution,” he explained. 

He emphasized that this project differs significantly from others in the world. It was based on studies of the Earth's behavior throughout its existence and observations of the nature of our environment.

Another product from Giem’s research is transformed organic matter. Recognizing that plants have specific nutritional needs based on their use —flower plants requiring more phosphorus, and fruit plants needing more potassium, for example— the ongoing work within the Giem research framework aims to create mineral-organic fertilizers. These fertilizers are formulated to provide the nutrients needed for a specific crop or for a specific stage of the crop.

“Synthetic fertilizer industries, which produce fertilizers through a chemical process different from the organic one, engage in similar nutrient customization. However, the production of these chemical fertilizers entails significant energy consumption and generates a high amount of greenhouse gases (GHGs). In contrast, our materials do not require so much energy and produce almost no GHGs,” said Uribe.

The researcher pointed out that these natural waste materials provide a much broader diversity of microorganisms than synthetic alternatives. This diversity enhances the ability of crops to better withstand attacks from predators, “as a soil rich in microorganisms provides a natural defense against pests.”

“This is the type of inputs that are used in organic agriculture. We add value by creating latest-generation slow-release fertilizers, which deliver nutrients at the time the plant requires it,” he said.

Organic waste from households generated in some Antioquia municipalities and industrial agricultural waste is used as the primary raw materials to produce environmentally-friendly fertilizers. Photo: Communications Office / Alejandra Uribe

Recovering soils: a long-term challenge

Another aspect to be highlighted is that the products resulting from Giem’s research also help in the recovery of areas impacted by human activities, such as intensive agriculture or mining. “We incorporate microorganisms into this organic material that naturally fix nitrogen in the soil, mirroring the processes in nature, particularly in forests. Many agrosystems have been treated with so many chemicals that are killing these microorganisms,” said Uribe.

Professor Peláez emphasized soils are deteriorating and degrading due to the absence of microorganisms in the formulation of synthetic fertilizers. Microorganisms are fundamental for agricultural production, which is why they must be incorporated into these fertilizers. Soil is a finite asset.

He remarked, “Now what we have to do is work towards consolidating a program that allows us to leverage our comparative advantages. We aim to establish a model based on the generation of value-added products, and energy from residual biomass. By examining the model’s potential, we can formulate a program that will allow us to make our country more competitive in agriculture.”