Laboratory Study On Sanitary Sewage Treatment By Microwave Method

In recent years, Microwave discipline has vigorously developed the discipline. However, microwave theory and application research is in the lower stage. This paper has presented the basic microwave frequency characteristics and physical characteristics in easy way, and synthesized the elaboration in recent years the microwave method used in the environment. Microwave has widely used in the chemical extraction and purification, catalysis, and other aspects applications such as in the microwave coagulation and precipitation, disinfection. This paper declares that microwave method, chemical method, biological method be application in sewage, and discuss the respective characteristics of these methods, in the results, microwave treatment of sewage have the advantages, as following:(1) shorten the process to speed up the process of reaction;(2) treated water directly to be used and sludge resourcelization;(3) reduce occupation of land resources;(4) reduce construction cost of the investment and operation costs.This paper discussed that Al₂(SO₄)₃ amount, pH, microwave field impacted the effect of treating waste water by microwave. The experimental data coming from "first experiment", "single-factor test", "verification experiment", have illuminated the most influential factors by statistical analysis of orthogonal test through the SAS software, as following: The Al₂(SO₄)₃ amount of (P=0.02 <0.05) for the total removal of a crucial impact on the best microwave conditions (pH=6); in the Single factor experiment, it can be concluded: lower is pH value, better is microwave treatment of domestic sewage, but taking into account the practical application of domestic sewage (pH value between 7-8) adjusting the pH value will increase the sewage treatment process, time-consuming effort; Secondly, with the pH value in the 7-8, microwave efficiency only dropped by about 20 percent, but we can (more Al₂(SO₄)₃) improve its flocculation effect through other channels. In this experiment, the pH value is only surveillance, and does not visit the adjustment; finally, through these experiments, it can be concluded as following:The efficiency of microwave sewage treatment in the field of high heat and a short period of time to microwave treatment of domestic sewage, finally, through the verification experiment, the paper have re-verified of the first experiment, and has discovered a new research direction.The verification experiment is designed to be orthogonal experiment. Through visual analysis, statistical analysis, accurately confirmed that in theory microwave treatment of domestic sewage is feasible, and the project is a workable. Finally, the "first experiment", "single-factor experiment", "confirmatory experiment" on an experimental basis, and the microwave theory on the basis of the microwave treatment of sewage to study the mechanism. The results are as follows: Water is a strong polar material. Since water molecules of polarization and relaxation time is similar to microwave cycle, and its elements and the diameter of a pitch, the dipole moment in the microwave can easily venue from the original hot movement to follow the microwave field of high-speed cross with changed orientation, in this process, the microwave energy into heat in the water. Therefore water to absorb microwave has a good effect, the other strength of the polarity of the different elements of the microwave also has the corresponding absorption effect, which is microwave on sewage treatment can be the basis; In addition to sewage water, but also contains a lot of polarity, non-polar molecules formed by pollutants, such as certain minerals, some organic matter, suspended solids, bacteria and the process of accession to the additives and so on. The elements of these substances or whether polar polarity decision on the strength of the material is absorbed microwave and microwave absorbing the strong or weak, at the water molecules in the microwave get energy, and become excited state, when it is the role of other elements in water:(1) If the species has a polar molecule, microwave can strengthen this polar molecule in the microwave field in the rotational movement to reach or approach the 2.45 billion / second (such as the use of 2450 MHz microwave) for the speed of high-speed polarity Moment of energy and get it in a very unstable elements of the high-energy-class status, which could have a key vibration, and was eventually torn from the degradation of the water separated;(2) If it is not in itself a kind of molecular polarity (for example: Many organic compounds are not polar molecule, is not directly apparent to absorb microwave), is also available at high-speed rotation of water molecules between the passive high-speed movement, so that the kind of material elements and other elements have also generated intense friction between the collision, also available energy this part of the activity of some of the full nudity: firstly, it greatly increases the chemical reaction risk, or induce chemical reactions, or chemical reaction more smoothly, secondly, the process can improve the catalyst function, service life, and even make the original, which did not have catalytic function, have catalytic function, thus microwave can greatly accelerate the speed of chemical reactions, the last, the solid substances in water can produce the so-called "surface effection", so that the surface of solid material can be activated, and more easily integrate with the surrounding material. The water can greatly facilitate the solid particles of polymerization, settlement and water separation.