Analysis of Disinfection in Greenhouse Soils with Medium-Temperature Steam Produced by Solar Energy

Abstract

The soils of agricultural crops begin to suffer from arvenses and pathogens that are harmful to new crops after going through several production cycles. The chemical control of these pathogens is carried out through fumigants, which are applied at doses necessary to reduce the infectious potential at levels acceptable for crops. However, this may affect the biological, physical and chemical environment of the soil and, at the same time, the crops due to the toxic residues of these fumigants. In this work, the analysis of the pasteurization process of greenhouse soils sown with saladette tomato (Solamun lycopersicum) and cucumber (Cucumis sativus L.) was carried out, using water vapor for the pasteurization process at a temperature of 120 °C, obtained from a parabolic cylindrical solar concentrator (PCC), eliminating the use of boilers that conventionally require this method and use a lot of electrical energy, which increases the cost of the procedure and also causes the pollution of the environment. An experimental design was built for which tests were carried out at different steam emission times for each tomato and cucumber test soil. For each emission, it was necessary to reach 80 psi of pressure, with a steam exit time of a maximum of 160 s. Once this disinfection technique was applied, the presence of microorganisms such as Cladosporium sp, bacteria, pathogens and fungi was determined by various culture media. By means of this, the pathogens eliminated were verified, which were promoted by the process with respect to the test soil.

The Use of Chitin for the Removal of Nitrates and Orthophosphates from Greenhouse Wastewater

“…Experimental data from studies on the maximum sorption capacity of CH toward P-PO 4 and N-NO 3 were described by the two best-known sorption models: the Langmuir isotherm (5) and the Freundlich isotherm (6).…”

“…Hence, this cultivation method poses the risk of significant yield losses [ 5 ]. The problem of the presence of pathogens in the wastewater-based culture medium can be solved by its disinfection, which is, however, very expensive [ 6 ]. For this reason, most producers do not recycle greenhouse wastewater and discharge it into the sewage system or directly into the soil without pre-treatment [ 7 ].…”