Study On Treatment Process Of High COD Concentration And High Color Wastewater Discharged From The Areca Deep Processing Factory

In 2019,the annual production value of the national betel nut industries exceeded40 billion yuan,and it is rising year by year.Deep procession of betel nut has become one of the pillar industry of Xiangtan city,Hunan Province.Since the betel nut wastewater has the characteristics of high water temperature,large organic matter concentration,poor biochemical property and difficult degradation;Since the betel nut wastewater has the poor treatment stability and high operating costs in the existing processing technology.The problem of wastewater treatment has seriously limitied the development of the betel nut processing industry.This study focuses on the actual production wastewater of a betel nut factory.Firstly,by studying the preprocessing and optimization conditions,the study discusses the optimal processing conditions of the preprocessing wastewater by the three biological methods of facultative oxygen,anaerobic oxygen and aerobic oxygen.On this basis,an inverted A~2/O combination process was formed.Then the GC-MS and metagenomic high-throughput sequencing methods were used to analyze the transformation of organic components and biological flora during the combined process.Finally the combined process was further studied in the application of the actual betel nut wastewater processing project.The conclusions are as follows:(1)Sludge flocculation adsorption plus coagulation sedimentation method can process betel nut wastewater better,and its COD and chroma removal rates are respectively 74.1%and 96.8%,which is better than the above two separate preprocessing methods.(2)The three biological methods of facultative oxygen,anaerobic oxygen and aerobic oxygen can obtain better reprocessing effect with the preprocessing betel nut wastewater.Under the optimal conditions,the COD and ammonia nitrogen removal rates of the facultative biological method are respectively 56.24%and 44.81%.While the COD removal rates of aerobic and anaerobic biological methods are respectively52.25%and 33.39%.According to the results of GC-MS analysis,the main pollutants in betel nut wastewater are phenolic compounds,accounting for 70%;the three biological methods of facultative oxygen,anaerobic oxygen and aerobic oxygen can effectively degrade these pollutants,and their degradation rates are as follows:Aerobic oxygen is superior to both anaerobic and anaerobic oxygen.(3)In the inverted A~2/O combination procession,the dominant bacteria in the facultative oxygen,anaerobic oxygen and aerobic oxygen biological systems are the same.But the relative abundance ratio is quite different.The relative abundance ratio of Proteobacteria,which can effectively degrade the aromatic compounds in the wastewater account for respectively 50.86%,22.37%and 40.2%.It was further confirmed that the P.fuliginea Povalibacter genus played an important role in Proteobacteria.(4)According to the above experimental results,the actual project of 30m3/d betel nut wastewater was designed by the process of“sludge flocculation adsorption plus coagulation sedimentation plus inverted A~2/O”.When the influent COD concentration was around 9000mg/L,The removal rates of COD and ammonia nitrogen in the effluent after processing were respectively,96%and 97%,which match the design requirements.