Research On Biological Contact Oxidation Technology Based On Basalt Fiber

The black and smelly river course is the difficulty of surface water environment management in our country at present.Research on new materials,new processes and new equipment is of great significance for solving this environmental problem and realizing sustainable development.As a new kind of green material,basalt fiber has attracted more and more attention because of its degradability and no secondary pollution.Based on the research of domestic and foreign scholars,this experiment constructed a biological contact oxidation device with basalt fiber as a new biological carrier to study the purification efficiency of the treatment technology for black and smelly water bodies in river channels.This study will develop a new kind of biological carrier filler with environmental protection and high efficiency.On the one hand,it is committed to solving the serious problem of black-smelly river channel pollution,and on the other hand,it actively expands the new application direction of basalt fiber,which has important scientific research value and social significance.The biological carriers of basalt fiber and common elastic filler were studied.Basalt fibers were modified with silane coupling agent（KH550）and treated with biological contact oxidation process.The removal rates of COD,NH₄⁺-N and TP were compared and analyzed by changing the Hydraulic Retention Time（HRT）and filling ratio under the same test conditions,so as to compare the treatment performance of the two different fillers.The results were as follows.（1）The effect of HRT on the decontamination performance of the two systems was different.Basalt fiber carrier system was less affected by HRT,and the removal rate of pollutants tend to be stable when HRT was greater than 24h.On the contrary,the stereoelastic packing was greatly affected by HRT,and the removal rate of pollutants increased with the increase of HRT.（2）The filling ratio of the fillers had a significant effect on the removal of pollutants in both systems.With the increase of the filling ratio,the removal rate of pollutants gradually increased,and the two groups of systems reached the peak at the filling ratio of 50%.（3）Under the condition of controlling HRT=24h and filling ratio of 50%,the two systems operated stably for 30d.The removal rates of COD,NH₄⁺-N and TP by the biological contact oxidation system of basalt fiber carrier reached 81.3%,70.9%and 53.3%,respectively.At the same time,the system could stabilize the DO of water more effectively,and the purification performance was obviously better than the ordinary elastic packing.Basalt fiber was modified with 0.1mol/L HCl and 0.1mol/L NaOH.The effects of COD,NH₄⁺-N and TP were investigated by changing the system HRT and filling ratio,and the modification methods of basalt fibers were compared and analyzed.The results were as follows.（1）In systems with different modification methods,HRT had little influence on the removal efficiency of pollutants（NH₄⁺-N,TP,COD）.When HRT=24h,the removal rate of pollutants in the alkali system was close to the highest value,and the water amount per unit time of the system was guaranteed.HRT should be used for 24h.（2）Although alkali modified system had better water purification performance than acid modified system,it still had a certain gap with KH550 modified system,especially in terms of phosphorus removal.Microbial abundance and community of basalt fiber and common elastic packing system were analyzed by high throughput sequencing.The dominant genera of the two systems were found to be the same:Sphaerotilus,Nitrospira and Rhodoferax.The relative abundance of common filler system was up to 40.01%,while that of basalt fiber system was only 25.05%.But the microorganism diversity of basalt fiber system was higher,which indicated that the biological diversity plays a vital role in the efficiency of nitrogen and phosphorus removal.The synergistic effect of various microorganisms was more conducive to the purification of sewage.