The Study On Biological Media And Its Application

In practical organic wastewater treatment process, due to many organic wastewater lack of trace metal element, which could lead to the decrease of anaerobic microorganism activity, and affect the biological treatment effect.The main purpose of this experiment is to load trace metal elements in ceramsete, which could slowly release trace metal element. And thus increase the biological availability of trace metal element, improve the processing efficiency of micro- organism, reduce the labour and raw material cost, which brought by excessive input trace metal elements.The experiment use fly ash and activator as main raw material, adopt steam curing method to produce ceramsite. By using single-factor experiment and orthogonal test to ascertain the suitable formula of ceramsite, the experiment indicated that the best formula of ceramsite is that: fly ash, cement, lime, gypsum, CaCl₂, Na₂SO₄ and NaCl respectively are 73.4%, 4.68%, 7.34%, 1.84%, 0.46%, 1.84% and 0.46%. meanwhile, by inspecting the effects of different technological conditions, it is found that the optimal technological conditions of drying time, drying temperature, steam curing time, steam curing temperature, moisture content and mixing water temperature respectively are 0.5h, 60℃, 14h, 100℃, 29.2% and 70℃.After studying on the adsorption experiment of sawdust and vermiculite, which indicated that the adsorption content of sawdust and vermiculite on trace metal element can almost balance after 10 hours. it indicated that the trace metal element concentration of reactor solution which released by ceramsite verged to balance after 4 days.It can be sure that the optimal concentration of trace metal element Ni²⁺, Fe²⁺, Co²⁺, which the microorganism needed, respectively are 0.4mg/L, 7.2mg/L and 0.1mg/L, through adding trace metal element in microorganism reactors. By going on contrast test among control group, single trace metal element group, mixing trace metal element group, common ceramsite group, commodity ceramsite group and modified ceramsite group, it is found that the COD removal efficiency of microorganism in these microorganism reactors respectively are 72.84%, 74.95%, 78.53%, 80.63%, 82.63% and 91.79%. The COD removal efficiency of reactor which added modified ceramsite is the highest, more than 18.95%, contrast with control group.Using dynamics analysis found that the process of microorganism degradation is first-order reaction, their reaction rate constant are respectively 0.1129d^-1, 0.1228d^-1, 0.1356d^-1, 0.1671d^-1, 0.1720d^-1 and 0.2302d^-1,the reaction rate constant of modified ceramsite is significantly higher than any other groups, especially than the control group, which indicated that adding modified ceramsite in bioreactor can significantly increase the activity of activated sludge, reflecting that modified ceramsite has more superior process organic wastewater performance than other ceramsites and directly adding trace metal element in bioreactor.