The Study On A New Technology Of Rope-Biofilm Carirers’ Natural Oxygen Supply In Wastewater Treatment

The water crisis is another world problem for human after oil crisis. Currently, the mainly method totreat wastewater is active sludge and biofilm. Advantages and disadvantages are both in the twomethods. Blast aeration used in aerobic of the two methods can make the wastewater treatmentequipment produces a larger energy consumption. Generally, the electricity cost accounts for1/3of totaloperation cost in sewage treatment plant. Meanwhile, blast aeration cost accounts for50%～60%inelectricity cost. Under the natural ventilation, the study made biofilm carriers hung on the fixed device,and then, the sewage flowed through the carriers; it would form some biofilms on carriers. The organicin wastewater would be degraded for microorganisms’ metabolism on biofilm. Paper studiedreoxygenation efficiency of different height natural oxygen supply biofilm carriers, compared thebiofilms’ growth efficiency of three biofilm carriers, and had a optimization on these biofilm carriers. Atthe end, there was a study on continuous dynamic operate experiment of the new technology. Themain conclusions were as follows:(1) DO in water and temperature was inversely proportion. The higher temperature, the lower DOin water. Under different temperature, DO in water was different. Height of rope-biofilm carriers’reoxygenation was saturation and flow on carrier was correspond relationship in the new technology.Under10.9℃,biofilm carriers’ height was5m, inlet flow2.3ml/s could make dissolved oxygensaturation, DO was11.1857mg/L. Under17.0℃,biofilm carriers’ height was6m, inlet flow2.5ml/scould make dissolved oxygen saturation, DO was9.7024mg/L. Under15.0℃,biofilm carriers’ heightwas7m, inlet flow2.8ml/s could make dissolved oxygen saturation, DO was10.0519mg/L.(2) Compared with polyacrylonitrile and polyamide, polyethylene terephalate fiber used inrope-biofilm carrier could produce higher biofilm growth efficiency.(3) Under20～25℃, inlet COD400±5mg/L, pH7.0, inlet flow2.1ml/s, the time of polyethyleneterephthalate fiber biofilm carrier appeared levelⅡ from top to bottom was: inlet water of biofilmcarrier was1.25h；1m high biofilm carrier was2.42h；2m high biofilm carrier was3.92h；3m highbiofilm carrier was5.67h；4m high biofilm carrier was8.08h；5m high biofilm carrier was10.42h.(4) After optimizated of new technology of rope-biofilm carriers’ natural oxygen supply, theoptimum condition was: initial concentration181.315mg/l，pH6.996and flow1.978ml/s. On thiscondition, COD treated was18mg/l and COD removal efficiency was90.12%.(5) Under20℃,5m high biofilm carrier, paper studied the continuous dynamic operate experimentunder the optimum condition. Results showed that:1、Removal rate of SS was very low, the effect wasnot remarkable. Inlet SS was480.00mg/L, the outlet SS was354.69mg/L.2、Under continuous dynamicoperate, COD(wastewater treated)≤50mg/L. The COD removal rate could be85%～90%.3、Undercontinuous dynamic operated, inlet NH3-N was78mg/L, outlet NH3-N was20mg/L. And the averageNH3-N after long time continuous dynamic operated was19.79mg/L.