Study On Characteristics And Application Of Pipe-cone Shape Filter Bio-bed

According to the analysis of biological growth, flow destributing, material transfering, precipitation and separation for the biological contact oxidation reactors, and based on theory and experimental research of the pipe-cone shape filter bio-bed, the results can be concluded as follows:(1) Because of the pipe-cone shape filter bio-bed packed at random, the settling area and the capability of sedimentation and entrapment can be greatly improved. On the experimental condition, the horizontal projection area of filter (settling area be created) in every cubic meter reactor is equal to the settling area of the settling tank which the diameter is 6.3m. Compared to the non-filter reactor, the settling efficiency of the pipe-cone shape filter bio-bed can improve by 1.9 times in non-aeration condition and 1.3 times in aeration condition. The sludge concentration can reach at 6.89kg/m³⁸.31kg/m³ by increasing the living area and quantity of microorganism.(2) The tracer agent test shows that the flow pattern in the Pipe-cone Shape filter bio-bed is complete mixing. Owing to the unique framework of the filter, different flow characterisrstics are created in local area inside and outside of the filter, Which is benefit to aeration, mixing and material transfering. The flow condition inside the filter is a bit turbulent, so it will be benefit to habitation and propagation of microorganism. Because the bubbles are continually cut, obstructed, stroked and smashed by the filters, it prolongs the residence time of the bubbles and increase the contact time and area between the bubbles and water in the reactor, so as to improve the oxygen transfer ratio. The material transfering can be improved by the alternant change of the micro-environment. The results of the oxygen transfer ratio test show that the oxygen transfer ratio of pipe-cone shape filter bio-bed can increase by 33.33 %.(3) When treating the domestic wastewater at HRT of an hour, the removal rate of COD_cr and the organic volume loading come respectively up to 90% and 11.28kgCOD/m³, and theCODcr of effluent is less than 50mg/l. When treating the municipal wastewater at HRT of 2 hour, the removal rate of CODcr and the organic volume loading come respectively up to 88.3% and 4.62kgCOD/m3.d, and the CODcr of effluent is less than 50mg/l, which can meet grade one Primary A of Municipal Wastewater Treatment Plant Discharge Standard. The post-anoxic reactor of pipe-cone shape filter bio-bed can form Oxic/Anoxic process to improve the nitrogen removal efficency. At total HRT of 5.5 hours, the removal rate of TN for the process is 60%.(4) The results of shock loading test of the pipe-cone shape packed bed shows, under the temperature is below 10°C, pH parameter is below 5, chromium ion concentration is higher than lOmg/L, the reactor still has nice capability of treatment, so it can be used in the north and cold district, and be used to treat industrial wastewater and municipal wastewater which water quantity and quality fluctuate largely.(5) Through the analysis of organic degradation reaction kinetics, using the experimental results, the kinetics model of the pipe-cone shape filter bio-bed are obtained as follows:On the condition of simulated domestic wastewater, organic degradation law is: C - 337.04 exp(-30.305O(l - erfg), R=0.95;or specific degradation rate is:192.3.0.-225)611.1 + 5.eOn the condition of municipal wastewater, organic degradation law is: C = 299.9 exp(-25.677)(l - erfg), R=0.94;or specific degradation rate is:526.3.(5.-26.7)301 + SeBy the comparing, material balance model is similar to the specific degradation rate model bstance, but the latter does not describe organic degradation law inside the biofilm, and so the material balance model is more theoretic integrity.