Study On The Highly-valued Utilization Of Waste Oat Sugar As Supplement Carbon Source

To achieve better nitrogen and phosphorus removal effect in sewage system certain carbon source conditions should be satisfied.Most of the sewage systems in China have low organic matter concentration,and the proportion of carbon,nitrogen and phosphorus in wastewater is imbalance.Low carbon source seriously affects the efficiency of nitrogen and phosphorus removal.The waste sugar by-product of food industry is high in carbon element.If a new type of carbon source is developed for nitrogen and phosphorus removal of sewage,the cost of carbon source in the original sewage treatment system will be greatly reduced,and will find the way out for organic solid waste treatment from food industry,achieving highly-valued utilization of “controlling waste by waste”.Based on the theory of bio-fermentation and biochemical treatment of sewage,this study researched the feasibility of using waste sugar as carbon source by means of pretreatment,physico-chemical analysis and biofacies analysis.Pilot-scale and productive experiments were carried out to study waste sugar as the best application technology integration for nitrogen and phosphorus removal on the basis.The influent of Guangdong Sewage Treatment Plant was used as experimental water,and the CAST process was adopted to carry out the sewage treatment experiment.The carbon sources were commercial carbon sources and various kinds of waste sugar.Experiments show that waste sugar as a carbon source for nitrogen and phosphorus removal has high use value and stable treatment effect.Waste sugars as carbon source are appropriate,among which oat sugar is the best.During the experiment,when the influent COD concentration was below 100 mg/L,TN was about 25 mg/L and TP was about 2.5 mg/L,adding waste oat sugar increased the influent COD by 40-50 mg/L.The average concentration of total phosphorus in the effluent of the experimental group decreased by about 0.3-0.4 mg/L compared with the control group without carbon source,meanwhile the average concentration of total nitrogen decreased by 3-6 mg/L.The productive experiment showed that the waste oat sugar had better phosphorus and nitrogen removal effect than industrial glucose.However,the input of waste sugar is easily interfered by influent water quality or other factors and becomes unstable.In later period of productive experiment of waste oat sugar shows that the change of water temperature will also affect the efficiency of nitrogen and phosphorus removal to a certain extent.When the dosing concentration of waste oat sugar is about 150 mg/L,the final cost is about 0.1-0.15 yuan/ton of sewage(considering transportation tax and cost).The waste oat sugar cost is only about 30-50% of commercial carbon source,which is a appropriate carbon source for nitrogen and phosphorus to raise standards.