Spectral Analysis Of VFA And DOM In The Anaerobic Biological Treatment Of High Carbon Nitrogen Wastewater

Anaerobic Sequencing Batch Reactor（ASBR）has attracted numerous attention because of its low investment,convenient operation and easy management and so on.However,some problems like the long cultivation cycle of the anaerobic sludge and the Volatile Fatty Acids（VFA）is easy to form the accumulation in the anaerobic process have been restricting the popularization and application of the technology.Recently,Near-infrared（NIR）spectroscopy and excitation-emission matrix spectroscopy（EEMs）as two kinds of fast and efficient modern analytical techniques can reflect the changes of various substances in anaerobic process quickly.Therefore,this paper explores the feasibility of combining NIR and EEMs to monitor ASBR.In this paper,ASBR was used to treat the high carbon-nitrogen wastewater.The anaerobic sludge came from a sewage plant.After 79 days of stable operation,the following results were obtained:（1）The ASBR launched by the method of gradually increasing hydraulic loading.After 39 days of cultivating,the removal rate of COD was more than 60%.And the total nitrogen concentration almost remained uncharged,while the concentration of ammonia nitrogen increased a little.When the operation cycle was 96 h,COD concentrations in the influent and effluent were 9000¹0250 mg/L and 2000²500 mg/L respectively,and the removal rate of COD was more than 80%.At the same time,the concentration of VFA was about 600⁷00 mg/L in the initial reaction.After the process of stable cycle running,the VFA concentrations in the effluent was 200³00 mg/L.It proved that the reactor was in a state of stable running.（2）Setting up the VFA calibration model by the NIR.Firstly,using the wavelet denoising to pretreat the original spectrum and then establishing the model of VFA by combining with iPLS.The results showed that the predicted values which VFA calibration model established in the 9091.30⁹511.73 cm^-1 range had a good relationship with measured values,and the correlation coefficient r_c = 0.8275,RMSECV=0.3899.At the same time,24 samples were collected to verify the VFA calibration model.The results showed that the correlation coefficient r_p=0.8913,RMSEP=0.2453.It proved that the model was better for the prediction of VFA concentration.（3）The fluorescent properties of organic matter in the high carbon-nitrogen wastewater were determined by EEMs,and its relationship with COD removal efficiency and change of ammoria-nitrogen concentration were established.The results showed that their correlation coefficient（R²）were 0.9230 and 0.9140 respectively.This study demonstrated that EEMs could distinguish the transformation characteristics of organic matter and its relationship with carbon and nitrogen content in the process of wastewater treatment.Therefore ASBR could not only degraded the carbon-nitrogen wastewater effectively,but also combining with NIR and EEMs could be used to realize the realtime monitoring of the running ASBR and provide support for its stable operation.