This information is a summary of Deliverable DA1.1: State of the art of CO2 capture technology in water and technique of carbonated water for irrigation.
The deliverable begins with information related to the existing techniques for capturing CO2, and its potential application to the ceramic industry. It continues with a description of commercial solutions for putting in contact industrial gases with water.
Following, a brief theoretical introduction about carbon dioxide dissolution in water and the advantages of using carbonated water for irrigation.
The use of CO2 in agriculture is not a new technique, since it has been used for years. The application of CO2 in irrigation water is known as carbonic fertirrigation, and consists of the use of carbonated water for irrigation. It is a technique that provides a quantity of CO2 to irrigation water. As a result, dissolved carbonic acid is obtained, which lowers the pH and causes various bicarbonates to react with carbonates and other salts present in the water. Afterwards, the carbonated water receives the usual fertilizers for irrigation whose solubility improves in slightly acidic water.
The deliverable also contains some basic knowledge about soil respiration, which is a serious problem for the European Union. Indeed, slight changes on soil respiration can significantly influence the atmospheric concentration of carbon dioxide.
In addition, the influence of salinity, sodicity and boron levels on several crops has been analysed, since the gases that come from a spray drier could contain traces of these elements as they may be partially solubilised in the water used to capture CO2.
The most relevant sources of information consulted are detailed and analysed to highlight the pertinent content. The information gathered is all related with carbon capture in water and with carbonic fertigation techniques. Scientific journals, doctoral thesis, books, guides, projects of similar topics, webpages and news have been consulted to prepare the document.
Afterwards, an initial characterisation of the process streams involved is given: hot gases coming from the dryer of a ceramic slurry (spray drier) and irrigation water. The data found in the literature indicate that the gas stream that exits from a spray drier has low carbon dioxide concentration, that is to say, carbon dioxide is very diluted. For this reason, CO2 capture conditions should be optimised to improve the performance of the whole system.
The properties of the irrigation water in the south east of Spain have also been obtained from the consulted bibliography. They have a pH between 7.5 and 8.0. In the same way, soil pH reaches the same values. This is due to the presence of calcareous soils and to a rainfall pattern below 400 mm per year. These factors have two main agronomic consequences, some strong acid must be used in the irrigation waters to avoid calcareous precipitation and, even more important, the plants have problems of absorption of heavy metals (basically iron) and these must be supplied by the farmer in chelates form.
Through the implementation of action A1, it can be concluded that a lot of literature is available related to carbonic fertirrigation, showing the benefits of the use of carbonated water for the development of plants. Moreover, no negative agronomic effects are expected due to the toxicity of heavy elements carried by the irrigation water, due to the low concentration of these elements in the spray-dryer exhaust stream gases.
The analysis of all the data gathered during this action shows that the current systems used to enrich irrigation water use pure CO2 instead of diluted one. A few references have been found using CO2 from combustion gases where CO2 is diluted. However, all of them refer to the capture of CO2 for the neutralization of waste water, and not for irrigation purposes. Different technologies are available in the market for the dissolution of pure CO2 in irrigation water.
During the project (action C1), the consortium will be studied how to adapt them to the specific working conditions of the industrial facilities and the selected plot to be irrigated.
Finally, several projects of great interest related to the Fertilife project have been identified.
Their coordinators as well as professionals working with CO2 capture and uses will be contacted to share experiences through networking activities (action E2), which will also permit the dissemination of Fertilife Project.