Generating nitrate and nitrite on green oak lettuce in hydroponic farming by plasma system

Abstract

In this study, we developed an effective methodology to determine the suitable plasma-based generating system of reactive nitrogen species (RNS) targeting hydroponic farming systems using a full factorial design with center points and blocking. A 2k with 2 blockings plus 2 center points design was employed in the experiment to develop an efficient analytical model for nitrogen solution concentration and hydroponic vegetable growth incorporating the plasma discharge system process parameters, including water flow rate, plasma discharge duration, and air flow rate. This study designed and constructed an air plasma discharge system with DC power supply. Thereafter, nitrogen solution was generated under a parameter conditions setting by the design of experiments (DOE) method. RNS solution, which contained nitrate (NO3-) and nitrite (NO2-) ions with P and K added, was passed through the hydroponic system for growing green oak lettuce. The most promising plasma-generated nitrogen solution parameters were obtained for this set up at a water flow rate of 6 L/min, discharge duration of 60 min, and activated air flow rate of 60 mL/min.