Effect of Bacterial-algal Biostimulant on the Yield and Internal Quality of Lettuce (Lactuca sativa L.) Produced for Spring and Summer Crop

Plant biostimulants can enhance crop nutrition status, stress tolerance, yield and quality in an environment-friendly manner. The aim of this study was to determine the effect of algae and bacteria preparations on the yield and nutritional parameters of leaf and romaine lettuce cultivated for spring and summer crop. The application of a combined biostimulant consisting of plant growth-promoting bacteria (Bacillus licheniformis, Bacillus megatherium, Azotobacter sp., Azospirillum sp., and Herbaspirillum sp.) and freshwater algae (Chlorella vulgaris) was done by watering the lettuce every 14 days, and a determination of the fresh weight, total antioxidant capacity, and total carotenoids content were performed. The result revealed that the application of bacterial-algal preparation significantly affected the plant weight of both romaine and leaf lettuce in the spring and summer seasons. The highest increase in the weight of romaine lettuce reached 18.9% in the spring crop, while in the case of leaf lettuce, biostimulant treatment led to a 22.7% higher weight in the summer crop. Total antioxidant capacity and total carotenoids content showed increased values in the summer crop of romaine lettuce, while for the leaf lettuce there were no differences between treatments. Therefore, the positive effect of bacterial-algal treatment on lettuce yield, total antioxidant capacity and total carotenoids confirm that it could be applied for improving romaine lettuce yield quality and quantity, especially in stress, summer conditions

Mass Production of Plasma Activated Water: Case Studies of Its Biocidal Effect on Algae and Cyanobacteria

Efficient treatment of contaminated water in industrially viable volumes is still a challenging task. The hydrodynamic cavitation plasma jet (HCPJ) is a promising plasma source for industrial-scale generation of biologically active environments at high flow rates of several m(3)/h. The combined effect of a hydro-mechanical phenomenon consisting of hydrodynamic cavitation and electrical discharge in cavitation voids was found to be highly efficient for large-volume generation of reactive oxygen species, ultraviolet (UV) radiation, and electro-mechanical stress in a liquid environment. Here, the persistence of biocidal properties of HCPJ-activated water (i.e., plasma-activated water (PAW)) was tested by the study of algae and cyanobacteria inactivation. Algae and cyanobacteria cultivated in media containing PAW (1:1) were completely inactivated after 72 h from first exposure. The test was performed at a total power input of up to 0.5 kWh/m(3) at the treated liquid flow rate of 1 m(3)/h. A beneficial modification of our previous HCPJ design is described and thoroughly characterized with respect to the changes of hydrodynamic flow conditions as well as discharge performance and its optical characteristics. The modification proved to provide high biocidal activity of the resulting PAW, which confirms a strong potential for further design optimization of this promising water (liquid) plasma source

Transition of cavitating flow to supercavitation within Venturi nozzle – hysteresis investigation

Cavitation is usually considered as undesirable phenomena. On the other hand, it can be utilized in many applications. One of the technical applications is using cavitation in water treatment, where hydrodynamic cavitation seems to be effective way how to reduce cyanobacteria within large bulks of water. The main scope of this paper is investigation of the cavitation within Venturi nozzle during the transition from fully developed cavitation to supercavitation regime and vice versa. Dynamics of cavitation was investigated using experimental data of pressure pulsations and analysis of high speed videos, where FFT of the pixel intensity and Proper Orthogonal Decomposition (POD) of the records were done to identify dominant frequencies connected with the presence of cavitation. The methodology of the high speed (HS) records semiautomated analysis using the FFT was described. Obtained results were correlated and above that the possible presence of hysteresis was discussed

Cyanobacteria 2010

Confernce proceedings deal with the problems of waste waters and cyanobacteria in reservoirs and ponds

Trophy and trophisation: Causes, consequences and terminology - Introduction

Summarisation of information about trophisation of water recipients