Study On Removel Of Carbon And Nitrogen In Fruit And Vegetable Wastewater By Submerged Aeration SBR Process

With the development of the economy and the improvement of people's living standards,the demand for canned fruit and beverages has gradually increased,and the fruit and vegetable processing industry have developed rapidly,the discharge of wastewater has increased year by year.Fruit and vegetable wastewater has the characteristics of high organic content,large changes in water quality and quantity,more suspended solids,and good biochemical properties.If the processing is not in place,it will seriously threaten the local water environment and soil safety.Therefore,it is extremely urgent to develop a cost-effective fruit and vegetable wastewater treatment reactor,which is of great significance for protecting and improving the water environment and soil in the local area.The core of this paper is to remove carbon and nitrogen from fruit and vegetable wastewater.In order to realize effectively remove organic matter and nitrogen in fruit and vegetable wastewater,In this test,a time-controlled mechanical batch reactor with stirrable aeration developed by the research group was used as an experimental device?a self-controlled intermittent inlet section aeration treatment system,patent number:ZL201510432180.5;A laboratory direct aeration aeration device,patent number:ZL201510431817.9?,using intermittent water inlet,intermittent aeration operation mode.the effect of the reactor on the removal of carbon and nitrogen in the fruit and vegetable wastewater and the change of sludge performance is firstly investigated.Then,under the condition of volume load of 2.0kg COD/?m3·d?,the optimal operation condition was found by exploring the number of water inflow,stop aeration ratio and speed of different single variable factors and comparing the test results.Finally,a dynamic model of matrix degradation was established to verify the test results.The tester lasted for 133 days.The main research contents and conclusions are as follows:?1?During the volumetric load increase phase,the test is carried out under the conditions of volume load 1.2kg COD/?m3·d?,1.6kg COD/?m3·d?and2.0kg COD/?m3·d?.After the test is stable,the effluent COD concentration is stable between 42 and 48 mg/L,and the removal rate was maintained above 97%.The effluent ammonia nitrogen concentration was stable between 1.62 and 2.94 mg/L,and the removal rate was maintained above 97%.The effect of carbon removal and denitrification is similar.It shows that the reactor has a certain impact load resistance.?2?During the volumetric load increase phase,the sludge concentration inside the reactor changed significantly from 5124mg/L to 7129mg/L,and the MLVSS/MLSS value reached 78%,indicating that the sludge activity is good,and the carbon removal and denitrification ability is efficient;The sludge sedimentation performance index SVI increased from 82 mg/L to 117 mg/L,indicating better sludge sedimentation performance.?3?Under the condition of volume load 2.0kg COD/?m3·d?,the single variable was adjusted,and the comparison test was carried out to optimize the test conditions.Optimal operating conditions were three times influent water per day,The aeration reaction time was 30 min and the precipitation reaction time was 90 min.The rotation speed was 420 r/min,the average values of COD,ammonia nitrogen and total nitrogen in effluent were 44mg/L,3.63mg/L and 12.98mg/L,respectively.Average removal rates were 98.17%,96.56% and 90.3%,respectively.The carbon denitrification effect is better,and the reactor operates efficiently and stably.?4?Based on the Monod equation,the kinetic model of the degradation of the reactor matrix was established and deduced to obtain the kinetic model of COD degradation:?S₀-S_e?·Q/V=416.55?Se/80.26+Se?;Ammonia nitrogen degradation kinetics model:?S₀-S_e?·Q/V=0.7348?Se/334+Se?;total nitrogen degradation kinetics model:?S0-Se?·Q/V=2.0691?Se/10.89+Se?.The reactor has the advantages of cost-effective,good oxygen-dissolving effect and low noise,stable operation etc..This test provides a novel and efficient treatment method for the treatment of fruit and vegetable wastewater,and provides an importantreference value for practical engineering application of fruit and vegetable wastewater treatment.