One of the main challenges faced by wastewater treatment systems is to guarantee an integrated management of wastewater; in that way, the goals for wastewater treatment systems need to move beyond the protection of human health and surface waters and minimize the loss of resources, reducing the use of energy and water, reducing waste generation, and recovering resources and nutrients through usable products.
From the perspective of integrated management of wastewater and life cycle analysis, nutrient recovery not only reduce the depletion of natural resources, such as phosphate minerals and nitrogen; It also contributes to the recovery of water and energy, since during its recovery it is possible to obtain water with low pollutant load and reduce the demand and production of traditional fertilizers.
Currently, one of the limitations of nutrients recovery is associated with the technological schemes that must be incorporated, since they require a detailed knowledge of the characteristics of the treatment system under study and of the specific aspects of the quality of the wastewater analyzed.
In studies to carry out technological development for the integral management of wastewater, it is important to have a reference population that allows extrapolating the operational conditions obtained; in this sense, the university campuses that have wastewater treatment systems can be used as a reference to simulate the quality of wastewater generated in urban contexts.
In Colombia, the Universidad Autónoma de Occidente, has been characterized as a benchmark against its environmental responsibility and the strategy incorporated through the Sustainable Campus, in terms of wastewater management and the use of treatment by-products, for these reason, the incorporation of nutrients recovery processes can provide an important technical elements to be replicated at the national level and contribute to the generation of new knowledge in the face of the technical conditions required for the development of technologies for the integrated management of wastewater.
In this project, technical conditions for the recovery of nitrogen and phosphorus as a struvite and hydroxyapatite respectively were evaluated, taking as a pilot case the wastewater treatment system of the Universidad Autónoma de Occidente.
The project is being developed in three stages: Stage 1, Diagnosis of the performance of the treatment system, Stage 2, Analysis of the potential for struvite and hydroxyapatite formation, and Stage 3, Definition of operational conditions for the implementation of a nutrients recovery system on the Universidad Autónoma de Occidente.
Preliminary results have shown that:
- To promote integrated management of wastewater it is necessary to identify the stage of the system in which the recovery of nitrogen and phosphorus can be applied, since for the recovery of nitrogen in a preliminary way it was evidenced that the most adequate stage to recover struvite is at the initial stage of the process, while for the recovery of hydroxyapatite or calcium phosphates, the appropriate stage is at the end of the process.
- The main operational variables to promote the recovery of nutrients, that we need to adjust are the molar fractions of Mg:PO4-3, NH4+:PO4-3 and Ca:PO4-3 at the wastewater and solubilization pH and mixing time of the process.
Development of this research project has allowed to identified some important elements to establish technological and operational conditions for nutrients recovery, which is necessary for an integral approach in wastewater treatment systems.
Keywords: Nutrients recovery, integrated wastewater management, Sustainable campus.
6d. Water and sanitation
