La economía circular en la industria de la construcción: alternativa para el manejo y disposición de biosólido de plantas de tratamiento de aguas residuales. Caso de estudio PTAR el Salitre – Bogotá D.C.

Abstract

At present, the integral management of water resources is promoted and one of the fundamental pillars to achieve this objective is the construction and start-up of both industrial and domestic wastewater treatment plants, which is a benefit for the environment and It contributes to the recovery of bodies of water where it is normally made available. However, the final disposal of wastewater treatment by-products is becoming a technical and environmental problem for the purification units or systems that carry out this task. From a technical point of view, biosolids or sludge become a problem for treatment stations or plants due to the large quantity in which they are produced, the environmental problem into which they can be converted, and the concentrations of heavy metals and leachates existing in these. The amount of biosolids generated by wastewater purification activities grows day by day, due to the wastewater management policies and decontamination of water bodies proposed in our country, which promote the construction of new treatment stations or the expansion of existing ones. This research focuses on finding a viable alternative from the technical and environmental points of view, for the disposal of the biosolid in construction materials, using them as raw material for the manufacture of ceramic elements such as bricks. The Salitre Wastewater Treatment Plant (WWTP) was selected as the study area, which treats a flow of 4.0 m3 / s and generates between 4500 and 5000 tons of biosolids per month. For Bogotá the recovery of the Río Bogotá is essential, understanding this as an improvement for the quality of life of its inhabitants; For this reason, the expansion and optimization of the EL Salitre WWTP is proposed within the recovery plan of the Bogotá River, from 4.0 to 7.0 m3 / s, and the construction and commissioning of an additional WWTP (PTAR CANOAS) with a capacity of up to 14 m3 / s and a generation of approximately 12,360 tons per month. As can be seen, they are considerable quantities (approximately 20,000 tons) and it is necessary to think about generating different alternatives for disposal and recovery. To fulfill the objective of the research, a work plan based on 4 activities was developed: 1. Chemical, mineralogical and physical characterization of the raw materials for the manufacture of bricks (clay - biosolid ash - glass); 2. Elaboration of the ceramic elements taking into account the results of the characterization of the raw materials and a series of proposed experimental treatments based on factors such as: the percentages of incorporation of biosolid in its different forms (untreated, dry, ash) , and the firing temperature 3. Evaluation of the quality of the elements obtained taking into account the provisions of the Colombian Technical Standard NTC 4205 (masonry units of fired clay, bricks and ceramic blocks), through resistance tests to the compression, water absorption and initial absorption rate 4. Evaluate the concentration of metals present in the bricks by applying the “Toxicity Characteristic Leaching Procedure” (TCLP) leaching test. From the results obtained in the research, it was possible to establish optimal values ​​for critical variables within the brick manufacturing process, such as: the inclusion percentage of the biosolid ash, the glass inclusion percentage and the drying and firing temperature. .