An Experimental Study On Dissolving Struvite Crystal From Anaerobic React Process

Along with the industrial development of China,standard of living has been improved ceaselessly, the industry of alcohol, starch and citric acid of China has being developed quickly, the output of these industries has mushroomed. However, the pollution of environment became more seriously coming along with the development, the capability of dealing with "three wastes" is a baptism to the technology of environmental protection.The wastewater from the production process of alcohol, starch, protein and other agricultural products can be easily biodegraded with high concentrations, the mature process is "anaerobic + aerobic"(two step of biological treatment process). However, in the anaerobic process (mainly contains UASB, IC technology and EGSB) with a high removed ration of the wastewater with high concentration, because of the circumfluence of effluence, struvite appears in the anaerobic system, because of the struvite, the pipes, pumps has been seriously blocked, and it take up the effective volume of the reactor.The topic mainly researches the removed capability and removed ration of the struvite from the anaerobic system using the acetic as the main medicament. From the results, we can see:(1) Acetic is a weak acid, the metal corrosion of this acid is very weak, but it has a strong ability to dissolve the struvite.(2) In the case of the concentration of acetic solution from 1.8% to 36% ,within 10 h ,the maximum average dissolved ratio of struvite appears in the concentration of acetic solution 36%, the ration is 1.36 g/h, the minimum average dissolved ratio of struvite appears in the concentration of acetic solution 1.8%, the ration is 0.26 g/h.(3) In the different concentrations of acid solution, the largest saturation of struvite also varies. In the acetic solution 36%, the saturation of struvite is 16.69 g, the time to be saturated is 53.3 h; in the acetic solution 1.8%, the saturation of guano rime is3.49g, the time to be saturated is 46.3 h.(4) In the acid solution in the solution, when the struvite and iron plates appears at the same time, it has little effect to the dissolving of the guano rime, but the corrosion of the iron plates has been effected, the corrosion ratio and corrosion quantity became be reduced.(5) The dissolving of the struvite with acetic can be effected by the temperature, the liquid disturbance, the contact areas and so on. Acetic is organic acid, it is the intermediate product of anaerobic process, it is easy to be used by methane-producing bacteria for biological decomposition to methane, so it will not seriously effect the pH of the wastewater, and it will not cause secondary pollution.Using the acetic to dissolve the struvite in the anaerobic system is a useful measure, and it provides the elements to popularize and use the high- efficiency anaerobic reactor to wastewater of high concentration.