Research On MBR Membrane Component Integrity Detection Based On Fluorescence-ultraviolet Spectroscop

Membrane bioreactor（MBR）is gradually applied to the field of sewage treatment due to its high effluent quality,small footprint,and high pathogen removal rate.It is one of the most promising water treatment technologies.However,once the integrity of the membrane module is damaged,it will cause serious consequences.Macromolecular organics,colloids,bacteria,viruses and other microorganisms in the raw water will enter the water outlet through the damaged location,putting the system’s effluent water quality at risk and affecting water health.Therefore,how to detect membrane damage in a timely and effective manner and ensure membrane integrity are particularly important for drinking water safety and sewage discharge standards.It was invested the detection method of MBR membrane module integrity based on the combination of fluorescence spectroscopy and ultraviolet spectroscopy in the paper.Under different working conditions,the integrity of membrane components was detected and analyzed by fluorescence and ultraviolet spectroscopy,a detection model combining fluorescence and ultraviolet was constructed,and a portable membrane integrity detection system based on the principle of spectroscopy was developed,To lay a theoretical and technical foundation for the integrity of the spectral detection membrane module.The relevant research conclusions are as follows:Based on the MBR supernatant scanning,the effluent when the membrane module is intact,and the effluent when the membrane module is damaged by three-dimensional fluorescence spectroscopy.At the same time,combined with the molecular weight test of high performance liquid gel chromatography.It is determined that the microfiltration membrane in this study has a better retention effect on tryptophan-like substances with large molecular weight.The tryptophan material retention effect is better.Fluorescence emission spectroscopy,fluorescence area integration,and two-dimensional correlation spectroscopy were analyzed in different damage rates,times and sludge concentrations.The core indicators indicating membrane damage were obtained:tryptophan-like substance T₁（Ex/Em=275/335 nm）and T₂（Ex/Em=230/340 nm）,the correlation between the T₁ peak and the breakage rate reached 0.963,and the correlation between the T₂ peak and the breakage rate reached 0.910.This showed that fluorescence spectroscopy can be applied to the detection of membrane module damage rate.Ultraviolet spectroscopy was performed on the effluent before and after the membrane damage with different damage rate,time and sludge concentration.As the damage rate increases,the absorbance of the ultraviolet logarithmic spectrum also increases.The Slope_280-350 of the ultraviolet logarithmic spectrum in the range of 280nm to 350 nm was calculated twice,and it was found to have a good correlation with the damage rate,and the correlation reached 0.923.Through the Gaussian fitting of the ultraviolet differential spectrum,as the damage rate increases,the value of the Gaussian peak A2-A6 increases,and the correlation coefficients with the damage rate reach 0.895,0.915,0.906,0.908 and 0.868,respectively.Compared with Gaussian peak detection,Slope_280-350 can better reflect the membrane performance under different breakage rates.Two fluorescence T₁（Ex/Em=275/335 nm）and ultraviolet Slope_280-350 that have the best correlation with the breakage rate were selected.Under different sludge concentrations,the two spectral parameters and the damage rate were subjected to multiple linear regression analysis to obtain the degree of fit with the damage rate.It was found that its fitting was higher than that of a single fluorescence spectrum or a single ultraviolet spectrum parameter and the damage rate.The membrane integrity detection method combined with fluorescence and ultraviolet was established.Based on the above work,a portable membrane integrity detector based on the principle of spectral detection was developed.The self-made portable membrane integrity detector was used to detect the integrity of membrane module.The short-period and long-period experimental tests of MBR under different working conditions were carried out,and the experiments were compared with particle counters and turbidity meters.The results showed that the portable membrane integrity tester had its applicability and superiority.