Experimental Study On The Treatment Of Artificial Sweetener Sodium Saccharin Production Wastewater

In recent years,artificial sweeteners have been detected in water environments in many countries around the world.Artificial sweeteners have been recently recognised as emerging contaminants and have received extensive attention.As the“first generation”sweetener,saccharin sodium has a complicated synthesis process,and the production wastewater has serious water pollution.It is difficult to achieve standard discharge by ordinary biochemical treatment,and further advanced treatment is needed.In addition,there have been reports of carcinogenicity of sodium saccharin,which is controversial about the toxicity of sodium saccharin.Based on its accumulation in the environment and potential hazards to humans and organisms,it should be considered to find a suitable method to effectively remove it and analyze its degradation mechanism.In this paper,the effluent from each stage of biochemical treatment of saccharin sodium production wastewater in a food factory in North were taken as the research object.Firstly,the quality of each wastewater was analyzed.Then combined with the water quality characteristics of biochemical effluent,in order to ensure that the color of biochemical effluent meets the three-grade discharge standard of Integrated Wastewater Discharge Standard（DB12/356-2018）,the electrocatalytic oxidation,ozone oxidation and PAC+SMF were adopted.Finally,electrocatalytic oxidation was used to degrade the saccharin sodium,and its degradation mechanism was studied.The main contents and conclusions are as follows:（1）Sodium saccharin production wastewater has deep chromaticity,high salt content,etc.But after biochemical treatment,all indicators are significantly reduced,and all indicators except chroma can achieve three-grade discharge standard.（2）In the decolorization experiment of biochemical effluent,all three methods can effectively decolorize the wastewater to meet the standard discharge.When the treated water volume was 1 m³,the cost was about 0.35～0.72,0.21～0.43 and 2.10yuan respectively.It can be seen that the cost of electrocatalytic oxidation and ozone oxidation is much lower than the PAC+SMF combination process,and the time required is the short,which can greatly improve the processing efficiency.（3）Electrocatalytic oxidation treatment of sodium saccharin showed that when the initial concentration of sodium saccharin was 50 mg/L,the dosage of electrolyte Na Cl was 0.1 mol/L,and the current density was 10 m A/cm²,sodium saccharin was completely degraded at 20 min.However when Na₂SO₄ is used as the electrolyte,the degradation effect on sodium saccharin is not obvious.（4）The kinetic study showed that the degradation of sodium saccharin was consistent with the first-order reaction kinetics model.The results of electrocatalytic mechanism showed that the contribution degrees of active chlorines and hydroxyl radicals were respectively 91.8%and 1.02%.It can be seen that the chlorine actives play a major role in the degradation of sodium saccharin.The results of the degradation mechanism study showed that most of the sodium saccharin were not completely degraded and converted into chlorinated alkanes.