The Characterization Of Soluble Microbial Products (SMP)

The effluent of the biological treatment system contains a variety of soluble organic matters, not only including organic pollutants in raw water which are hard to be degraded,degradable intermediate products and final degradable product, but also including a mass of soluble microbial products (SMP) which are produced by microorganism in the metabolic process. The existence of SMP will not only reduce the efficiency of biological treatment and the quality of effluent, but also affect the reuse of wastewater and the treatment of drinking water, ultimately may put the receiving water in danger. Therefore, to improve wastewater biological treatment efficiency and discharge standards the research about SMP has great significance. In recent years, the research about the influencing factors and composition of SMP is a hot spot in the wastewater biological treatment field, but various research are still in the preliminary stage, especially, there are a few works in our national.This topic investigated the characteristics of SMP production with glucose as substrate's synthetic wastewater respectively in the aerobic and anaerobic conditions, on the basis of TOC and other conventional indicators analysis and the determinations of SMP production under the influence of poison, using UV, GPC, SPE-GC/MS, LLE-GC/MS analysis methods carried out a more in-depth analytical studies in the main component of the SMP and the production and component changes of SMP under the influence of poison, based on the results puts forward the recommendations about corresponding reduction of SMP and subsequent treatment.It was found that after adding the toxic heavy metals Hg²⁺ (20-40mg/L), the production of SMP increased significantly, in aerobic condition SMP/S₀ (S₀ is the influent concentration of organic matter) increased from 0.037 to 0.059, in anaerobic condition SMP/S₀ increased from 0.056 to 0.068. In aerobic condition, the molecular structures of SMP degradating from glucose which is a simple matrix had unsaturated ketones, unsaturated aldehydes, conjugated diene, benzene etc. conjugated system characteristic. The molecular weight distribution presented bimodal (large and small molecular weight double regional) characteristics, the main components were esters, ketones, alkanes, alcohols, as well as a small amount of phenols, acids, hydrogen peroxide class and cyanide category. In anaerobic condition, the molecular structures of SMP degradating from glucose which is a simple matrix had conjugated double bonds characteristic and benzene etc. conjugated system characteristic, but the molecular weight distribution presented three peaks (large, medium and small molecular weight of the three areas) characteristics, mainly composed of benzene, alkanes, esters, ketones and alcohols, as well as a small amount of olefin and hydrogen peroxide class.This topic intends to find out the effects of SMP formation under the different processes and toxic, so as to choose to reduce the production of SMP and subsequent treatment processes provide a reference.