Experimental Study On Treatment Of Bath Wastewater By Traditional Activated Sludge + Magnetization Technology

Bathing wastewater is one of the main sources of domestic sewage,accounting for about30% of domestic sewage.Bathing wastewater has the characteristics of large water volume,low water pollution degree and relatively stable water quality,and it is a high-quality recycled water source.In today’s water shortage,the reuse of bathing wastewater will play an important role in saving water.With the growth of the global population and the deterioration of the ecological environment,people have begun to advocate the protection of the environment,conservation of resources,and the development of sustainable development.As the source of human life,water resources are particularly important.In order to protect the water ecological environment and save water resources,countries have carried out research on the reuse of wastewater.The research in European and American countries is relatively early.In the 1980 s,the research on the reuse of sewage was carried out,while the research on the recycling of bathing wastewater in my country began in the 1990 s.With the improvement of people’s quality of life,the discharge of bathing wastewater is increasing day by day,people gradually began to pay attention to the recycling of bathing wastewater,and carried out research on the recycling of bathing wastewater.In this experiment,an experimental study of the combined process was carried out with the bathing wastewater in the university as the raw water.The combined process is mainly composed of an aeration tank and a columnar reactor.Among them,the aeration tank fully aerates the bathing wastewater.The columnar reactor consists of upper and lower parts,the bottom is filled with activated sludge for biochemical reaction,and the upper part is added with a permanent magnet to generate a magnetic field.The magnetite particles are filled in the magnetic field for adsorption and filtration.The influencing factors of the combined process were determined by searching literature and preliminary experiments,which were: influent flow rate,aeration rate,thickness of magnetic layer,and thickness of sludge layer.The single factor test determined the best operating parameters of the combined process,and the operating parameters were determined as follows: influent flow rate: 5m L/min,aeration rate:5L/mim,thickness of magnetic layer: 4cm,thickness of sludge layer: 15 cm.Through the single-factor experiment comparison of the combined process before activated sludge domestication and the combined process after activated sludge domestication,the removal rate of activated sludge after domestication was higher.The optimal LAS removal rate increased from 52% to 94%,and the optimum effluent concentration decreased from 2.6mg/L to 0.39mg/L.The optimal removal rate of CODcr increased from 52% to 84%,and the optimum effluent concentration was reduced from 72.5mg/L to 37.5mg/L.The optimal turbidity removal rate increased from 68%to 91%,and the optimum effluent turbidity was reduced from 6.02NTU to 3.38NTU.In order to further improve the removal rate of LAS,CODcr and turbidity,the response surface experiment was carried out on the basis of the single factor experiment to optimize the operation parameters of the combined process.From the analysis of the response surface experiment results,it can be concluded that the influence of the influencing factors on the CODcr removal rate was from high to low: influent flow,thickness of the sludge layer,thickness of the magnetic layer,and amount of aeration.Among them the interaction between the two factors,the influent flow and the thickness of the sludge layer,was significant.The influence of the influencing factors on the LAS removal rate was from high to low: thickness of sludge layer,influent flow,thickness of magnetic layer,aeration volume.,the interaction between the influent flow and the thickness of the magnetic layer,the aeration amount and the thickness of the magnetic layer,the influent flow and the aeration amount,and the influent flow and the thickness of the sludge layer was significant.The influence of the influencing factors on the turbidity removal rate was from high to low: thickness of sludge layer,influent flow,thickness of magnetic layer,and aeration volume.Among them The interaction between influent flow and aeration rate is significant.From the position of the extreme point,it can be known that the removal rate of LAS,CODcr and turbidity was the largest under the condition that the influent flow was 5m L/min,the aeration rate was 5L/min,the thickness of the magnetic layer was 4cm,and the thickness of the sludge layer was 15 cm.At this time,the removal rate of CODcr was up to 80.7%,the removal rate of LAS was up to 97.9%,and the removal rate of turbidity was up to 96.7%.The optimized parameters were: the influent flow rate was 2.8m L/min,the aeration rate was 6L/min,the thickness of the magnetic layer was 3cm,and the thickness of the sludge layer was 16.5cm.After optimizing the parameters,the removal rate of the effluent index had increased,and the pollutant concentration had decreased.The LAS effluent concentration was stable at about 0.3mg/L,the CODcr effluent concentration was stable at about 17.5mg/L,and the turbidity was stable at about 3NTU.However,the combined process still has shortcomings.In the continuous water inflow experiment,the water effluent before 5 days can be kept stable and the water effluent was good.From the 6th day of continuous water inflow,LAS,CODcr,and turbidity all hs different degrees of effluent deterioration,among which turbidity effluent had the greatest impact.The main reason was that the magnetite particles filled in the magnetic field had been corroded and rusted under the immersion of oxygenated water for a long time,and the color of the effluent was slightly yellow.In response to this phenomenon,the measures that can be taken are to replace the magnetite particles regularly,which can effectively maintain the stability of the effluent.The microbial community diversity of sample A1 before domestication and sample A2 after domestication was compared and studied by high-throughput sequencing technology,and the following conclusions were drawn: the community richness of fungi in sample A1 was slightly higher than that in sample A2,while the community diversity of fungi in sample A2 was higher than that in sample A2.The community diversity of sample A1 fungi was high.The bacterial community richness of sample A2 was higher than that of sample A1,while the bacterial community diversity of sample A1 was greater than that of sample A2.The dominant fungal phyla of sample A1 are: Basidiomycota,Rozellomycota,unclassified＿k＿Fungi.The dominant phyla of sample A2 fungi are: unclassified＿k＿Fungi,Basidiomycota,Rozellomycota.The dominant phyla of sample A1 bacteria are:Proteobacteria,Bacteroidota,Actinobacteriota,Patescibacteria,Chloroflexi,Myxococcota,Acidobacteriota.The main phyla of sample A2 bacteria are: Proteobacteria,Bacteroidota,Actinobacteriota,Patescibacteria,Myxococcota.