Study On The Treatment Of Organic Wastewater By Nano-micron Bubbles With Ceramic Membrane

Industrial organic wastewater is characterized by high toxicity,high chromaticity and high concentration,the treatment of industrial wastewater is difficult.The traditional membrane bioreactor method covers a large area and cost a lot,which is prone to produce membrane pollution.The purpose of this project is to find a new combined process for the treatment of organic wastewater to improve the efficiency of membrane treatment and alleviate membrane pollution.In this project,nano-micron bubbles are used to replace the biomass in the membrane bioreactor.Nano-micron bubbles are combine with ceramic membrane to form a new process "membrane oxidation reactor",called as "MOR".First,the study compares the removal of the model pollutant dye methyl orange by nano-micron bubbles and ceramic membrane,the influencing factors were investigated.then,the treatment effect and pollution status by ceramic membrane and MOR are compared.Finally,the properties and treatment effects of the modified ceramic membrane are investigated.By means of scanning electron microscopy,infrared analysis and the measurement of contact angle,the surface morphology,functional group changes and hydrophobicity of ceramic membrane were observed.The followings are the research content of this topic:1)The tubular ceramic membrane is made into ceramic membrane components.Methyl orange is filtered by ceramic membrane in the way of dead end filtration.Firstly,the ceramic membrane filter device was built,The operating parameters,such as ceramic membrane aperture,ceramic membrane size,and transmememium pressure,were determined to explore the effects of temperature,pH value,concentration and pump speed on the removal rate and membrane pollution of the ceramic membrane.Experiment original ceramic membrane pore size is 43.6nm.Make sure the appropriate filter methyl orange concentration is 8mg/L,the optimum temperature is 20-30?,the pH has little effect on the filtration,When the rotational speed of peristaltic pump is 100r/min,the maximum removal rate of methyl orange during the test operation is 20%.When the experiments is run for 60min,the recovery rate of membrane flux is 50%,which is better than the membrane pollution under other pump speeds.2)In this experiment,the fluidic is the main component to produce nano-micron bubble.The whole device connects waste water tank,gas-liquid,mixing pump,jet device,pressure gauge and liquid flow meter in series to form a circulatory system.The wastewater circulating in the waste liquid tank is sprayed with nano-micron bubbles after pressurization,inhalation and pressure release at the jet device.At the same time,the bubble bursts releasing hydroxyl radicals.The operating parameters of the nanobubble generating device are adjusted.The device sucks air in the gas-liquid mixing pump and the jet device,and produces milky micellar nanometer bubbles in the waste water tank.The gas flow of nanometer bubbles is 1.6L/min and 36mL/min,respectively,the pressure is 0.22Mpa,and the liquid flow meter is 14L/min.Methyl orange was used as the simulated pollutant,and the device was used to removal methyl orange.The experiment was run for 60min,and the removal rate of methyl rate of methyl orange at 8mg/L by nano bubbles generated by the device was up to 32.5%.Nanobubbles constantly interrupt organic matter and eventually degrade into carbon dioxide and water,realizing complete mineralization without secondary pollution.3)Under certain conditions,methyl orange was treated with MOR system composed of nanobubbles and ceramic membrane.Under the same conditions,the highest removal rate of methyl orange is 47.5%.The experiment is run for 60min,and the removal rate is basically stable at 25%,high than the removal rate of methyl orange by ceramic film alone(20%).In addition,the MOR system treated methyl orange,and the test is run for 60min.The ratio of MOR's membrane flux to the initial membrane flux is 70%,which is higher than 55%of methyl orange treated with ceramic membrane alone.The addition of nano-microbubbles obviously improved the removal rate of methyl orange and alleviated the pollution of ceramic membrane.4)With the tubular ceramic membrane pretreated with nitric acid as the carrer,the copper oxide is loaded on the outer surface of the ceramic membrane and on the surface holes,so that the ceramic membrane has higher hydrophilic characteristics.Roasting in muff furnace can improve the dispersion of Cu2+,The ceramic membrane is combined with nano-micron bubbles to form a new Cu-MOR system.Cu-MOR process is used to treat simulated methyl orange wastewater under the same conditions.The treatment efficiency is improved by 5%-30%and the pollution of ceramic membrane is improved.The acid pretreatment increased oxygen content of the ceramic membrane surface and pore,the addition of copper oxide promotes the function of the nano-micro bubbles,at the same time reduce the ceramic membrane aperture,increased along with the interception of methyl orange molecules effect,the processing efficiency has been improved,the chromaticity is effectively removed,the treatment of dye wastewater reached the national standard.