Research On Evaluation Method Of Anaerobic Biochemical Effect Of Pharmaceutical Wastewater And Its Application

The biodegradability of wastewater is an important feature of wastewater and an important basis for engineering design,how to visually reflect the actual bio-chemical effect of wastewater in bio-chemical system is of great practical value to engineering practice.The purpose of this paper is to study the evaluation method of anaerobic biochemical effect of wastewater.Aiming at the shortcomings of the existing evaluation methods of anaerobic biodegradability of wastewater,improve on this basis,and propose an experimental device and evaluation method for wastewater anaerobic biochemical effect.Specifically,on the one hand,by adding a sampling sealing unit to the microreactor to ensure the air-tightness of the device,and filling the microreactor with N₂during the sampling process,the residual air is exhausted,and the mud-water mixture is prevented from contacting the air during the sampling process.That can solve the problem of residual O₂in the microreactor;On the other hand,by preheating the microreactor,the temperature difference is balanced before being placed in the constant temperature water bath of the Warburg respirometer,so as to avoid the problem that O₂introduction due to the pressure change in the microreactor due to temperature changes,so as to make the experimental results more accurate and better reflect the biochemical effects of wastewater in the actual anaerobic biochemical system.The optimal experimental conditions are as follows:control the pre-water bath temperature to38-40°C,fill the micro-reactor with N₂for 2 minutes,and add the mud-water mixture to the micro-reactor with a volume of 3m L.The experimental device and evaluation method for the anaerobic biochemical effect of wastewater proposed in this article have not been reported in the literature so far.In this paper,the anaerobic bio-chemical index（KA）is proposed,which corresponds to the removal effect and degradation rate of COD in the biochemical system to a certain extent,which better represents the degradation degree of pollutants in wastewater.The volumetric load of COD reaches 3.0kg/（m³·d）,the cumulative removal rate of COD reaches 80%,and the corresponding K_Avalue of 3.0 is used as the judgment value for evaluating the anaerobic biochemical effect of wastewater,that is,when the measured index K_A<3.0,it indicates that the anaerobic biochemical effect of this wastewater is poor.When the measured index K_A≥3.0,it indicates that the anaerobic biochemical effect of this wastewater is better.Through the research on the biochemical effect of the start-up process of the anaerobic biochemical system,the experiment shows that the relationship between the cumulative gas production of the anaerobic biochemical curve and the start-up time presents an obvious positive correlation law,that is,with the increase of the start-up days,the cumulative gas production presents an upward trend,indicating that the biochemical effect in the start-up process is gradually enhanced.To explore the internal relationship between anaerobic start-up process and biochemical effect,the K_Avalue of 3.0 is used as the basis for determining the start-up of anaerobic system.At this time,microorganisms have been basically adapted to wastewater water quality and bio-chemical environment,activity has been enhanced,bio-chemical effect is better.The influence of different factors on anaerobic start-up cycle is discussed,which is of guiding significance to shorten the start-up cycle and process optimization of anaerobic bio-chemical system.By constructing the RBF neural network start-up cycle prediction model to predict and model the start-up cycle of the anaerobic bio-chemical system,and to carry out error analysis,the results show that the anaerobic start-up cycle prediction model based on RBF neural network has high prediction accuracy and prediction effect,and has important guiding significance for anaerobic start-up cycle prediction.