Design of UVA Ultraviolet Disinfection System for Nutrient Solution Residual Liquid and Development of Microbial Online Monitoring System

If the nutrient solution used in the hydroponic system is recycled and reused without disinfection, the plant diseases are likely to spread. The current disinfection system still cannot conduct online monitoring of microorganisms at the same time as disinfection. In this paper, a UVA ultraviolet disinfection system and an online microbial monitoring system are proposed, which can conduct online monitoring at the same time as disinfection. This system includes the design of the disinfection system, the microbial online detection system and the microfluidic chip. The practical performance of the disinfection system and the microfluidic chip was verified by means of simulation and experiment. The relationship between the working power (P) of the UVA ultraviolet sterilizer used and its irradiance (Ee) is P = 29.98 Ee. The direct influencing factor of the ultraviolet disinfection rate of the nutrient solution residual liquid was the ultraviolet light irradiation dose. When the power of the ultraviolet lamp (radiation flux) is 30 W, the optimum wavelength is close to 300 nm, and the absorbance value is approximately 0.07. The error between bioluminescence detection and laboratory culture detection error is 0.002. The disinfection method and microfluidic chip proposed in this paper can be used in a greenhouse hydroponic system to reduce the impact of harmful microorganisms in the nutrient solution return on plants, and improve the effect of the return solution.