Greenhouse soil disinfectant treating by direct flame in rotating drum

In this work experimental and numerical results related to micro-organism population control in greenhouse soil by means of direct soil burning are reported, and an original device for this operation is presented. Results of the micro-organism soil treatment are also reported. In the perspective of evaluating high temperature side thermal effects on the greenhouse soil, biological and chemical effects of the soil treatment are described as well. The heating and the loss of water in the experimental tested configurations do not involve any meaningful transformation in the physical structure of the mineral present in the clay fraction. In fact, the slight transformations detected do not modify the fundamental structure, but they are essentially related to reversible loss of water. The loss of moisture and a light diminution of the organic substance have been anyway noticed by chemical analysis performed on the treated soil. The moisture concentration in the soil before and after the treatment becomes a very important index to prevent possible transformations of the organic substances in the soil, due to the heating effect. Pulverisation of the soil is possible if moisture levels decrease under a minimum level, and in this case it is also possible to perform an unwanted cooking of the clay present in the soil. Insofar we have considered that the water which is always present in the soil evaporates in an uniform way, balancing the local temperature and protecting the soil itself against the direct effect of the flame. In order to obtain a better understanding of the thermal effects of the phenomena related to the soil sterilisation process a numerical simulation of the proposed device has been performed and results are compared with experimental data.