Study And Application Of New Iron-based Nanomaterials For Phosphorus Adsorption In Sewage Biochemical Treatment Effluent

In China,cities,lakes and rivers are facing various water environmental pollution problems caused by excessive phosphorus.it is difficult to remove phosphorus in a economical and efficient way by biological method,chemical precipitation,ion exchange,membrane separation.Under this circumstance,the adsorption method has attracted much attention due to its less land occupation,simple process,and convenient operation,and can be applied to small and medium-sized sewage treatment plants of various biological treatment methods.In the research of adsorption method,searching for an efficient and economical adsorption material is the key to the development of phosphorus removal process,which is also a hot spot.?1?Actual wastewater dynamic adsorption experiment was conducted to investigate the effect of FM?new iron-based nano-phosphorus removal material?as a phosphorus removal adsorbent.Combinations technique of FM and three typical methods?anaerobic treatment,biofilm and activated sludge,which are the main bodies of the plants mentioned above?were conducted.The conclusions are as follows:Through the dynamic adsorption phosphorus removal experiment on the effluent of two rural sewage treatment stations in Kunshan and one sewage treatment plant in Suzhou for a whole year,,it is found that the effluent quality of the biochemical section of each sewage treatment facility is different.The TP concentration of the effluent from the biochemical section of the rural sewage treatment station is relatively high,ranging from 5.98 to 9.02 mg·L^-1with high volatility,while the TP concentration of the oxidation ditch in the large urban sewage treatment plant is low,at 1.68.-2.65 mg·L^-1 with good stability.In the combined process of FM adsorption treatment and the oxidation ditch,when the adsorption reaches the depletion point,the total phosphorus removal rate and the FM unit adsorption amount are 33.24%and 9.388 mg·g^-1,respectively,which were lower than 38.04%,19.729 mg·g-1,39.71%,and 16.959 mg·g^-1 of the biochemical section of the small rural domestic sewage treatment station with the anaerobic pool and bio-drum as the main treatment process.It can be seen that FM has a good adsorption and phosphorus removal effect on the biochemical effluent of a typical sewage treatment plant with anaerobic method,biofilm method and activated sludge method.Among them,FM is more suitable for small rural sewage treatment stations with high phosphorus concentration,high water quality fluctuation and small water volume.For different treatment processes and scales,appropriate design parameters can be selected according to the relationship between removal efficiency and utilization rate of adsorbent materials in order to achieve more c economical and efficient treatment effect..?2?The regenerative capacity and reusability of FM was investigated when the adsorption reached the penetration point by using the winter effluent from oxidation ditch of a sewage treatment plant in SuZhou as experimental water.The regeneration solution was 0.1 mol·L^-1 NaOH solution,and 5 cycles of adsorption-desorption-resorption-redesorption experiment were carried out and under the condition of constant water production.The conclusions are as follows:In order to make full use of the regenerative capacity of the NaOH solution,the regeneration flow rate is set to 0.5 times of the adsorption flow rate,which is 5 mL·min^-1,and the direction of the inlet and outlet water is downward and upward.The first regeneration efficiency of FM is 84.14%,having an obvious regeneration effect..In the condition of the same water production,the 5 cycles of adsorption-desorption-resorption-re-desorption of FM,with the increase of the number of adsorption-desorption,the unit adsorption amount and unit desorption amount of FM gradually decreased,but overall it still maintains good adsorption and desorption effects.Through the adsorption column regeneration and recyclability experiments,the new iron-based nano-phosphorus removal material is a recyclable material with good regeneration performance,no secondary pollution and reusable,and has high practical application value.?3?Demonstration projects were established in Jiangzhuang Village and Hongyuan Village of Nantong City to study the phosphorus removal effect and application value of FM in actual engineering.The conclusions are as follows:According to the operating data of the two pilot projects in a whole year,the influent water in the rural sewage treatment stations of Jiangzhuang Village and Hongyuan Village has some fluctuations with the running season and environment,but after the bio-drum+constructed wetland+After the treatment of the ecological pond+FM dephosphorization tank,the indicators of effluent including COD,NH₃-N and TP all meet the first-class standard of discharge standard of pollutants in urban sewage treatment plant?GB18918-2002?.It can be seen that the new iron-based nano-phosphorus removal material has a good treatment effect in the practical application of small rural domestic sewage treatment stations,and has a higher practical effect on optimizing the treatment process,further saving floor space,and reducing investment and operating costs.