Engineering and Architecture
Daniel Montané Calaf
Universitat Rovira i Virgili
Nanoscience, Materials and Chemical Engineering
Recovery and re-use of urban solid organic waste with WWTP effluent
In 2030 it is estimated that 60% of the population of the world will live in urban areas. People living in cities will produce an immense amount of solid waste and wastewater. Despite the will of municipalities to separate and classify urban waste, mixed waste streams that go to landfill or incineration still contain a large volume of biodegradable organic matter (for example, 50% in the city of Reus). This organic matter could well be used as raw material for the bio- industry or transformed in renewable energy.
Even though their contaminant levels and diversity present challenges for valorisation, organic urban waste streams can provide a significant volume of feedstock for the bio-industry all year round without any conflict with land use and food production.
WWTPs are capable of treating urban wastewater and converting it into effluents with an organic load below 125 mg/L. These effluents can not be used directly for human consumption and are returned to the sea, rivers or are used for irrigation.
The idea of the project is design a process able to recover the organic matter of the urban solid organic waste with the help of the liquid effluent leaving the WWTP. Selected urban solid organic waste, after elimination of big size solids as metals, plastics or inorganic materials, will be washed with the liquid effluent in a mixer-decanter unit. Project will have the support of Town Hall of Reus and WWTP of Reus.
The main objective of the project is the design, manufacture and use of the mixer-decanter. The design should allow the organic fraction, after mixing with the liquid effluent, to be separated into three streams: fraction of plastic floating on the liquid phase, fraction of solids on the bottom of the unit and an emulsion containing the organic phase that could be recovered.
The organic matter of the emulsion will be extracted by organic solvents and separated by evaporation of the solvent. The organic matter will be fully characterized. On the other hand, the water used will be characterized after separation and sent back to WWTP for treatment or conditioning.
The progress beyond the state of the art will be very important because at present, according to the knowledge of the supervisors, no technology is being developed to use an WWTP effluent to recover the organic fraction from the non-separated urban waste.
Some figures that can justify the ambition of the project. The city of Reus has 100000 inhabitants. Reus generates 40.000 tons of wastes per year. 35.000 tons of these wastes are brought to incineration. 50% of incinerated wastes are organic matter. The goal is recover the major part of these 17.500 tons of organic matter.
The benefits of the project for administrations are very important. In the first place, all the organic matter that will recover will not be incinerated, assuming a lower production of carbon dioxide. Then, the recovered organic matter can be used as raw material for the production of new chemicals.
37.5 hours a week
|This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 713679|