Effects Of Long-Term Storage On Water Quality And Electrocoagulation With Ultrasonic

In this paper, the water quality changes in long-term storage using raw water from pond, reservoir and river were researched in order to resolve the problem of water supply at the frontiers. Besides the general analysis of the water's quality, the molecular weight, polarity, volatility of organics was analysed. The removal of organics by electrocoagulation with ultrasonic was tested. Based on the research, the conclusions can be drawn:1) During the storage, the turbidity and the COD value were decreased exponentially. Along with the decrease of E.coli., the water quality of raw water could be considered improved.2) The microorganism acclimatized themself to the wane of nutriment by reducing their metabolize level, extending their specific area, utilizing more types of substrate. The odour in the storage water was mainly caused by the metabolism of fungi, actinomycete etc..3) In the storage, the proportion of 4KD-10KD increased, while those under 4KD decreased. Organics which could be volatilised easily or difficultly decreased fast at the early days, then decreased slow, but the organics which can volatilised easily decreased faster. Hydrophilic organics in the raw water decreased , while hydrophobe organics incresed. 4) Stainless steel and acid-resistant keramics showed less effect on the water's qulity, while the fiber steel which had used for storage in the experiment showed great effect.5) The addition of ultrasonic could remarkably enhance the removal effect of the organics in electrocoagulation treatment, and the removal rate was enhanced with the increasing ultrasound power. By the use of electrocoagulation at 3A/m2 in 30min, TOC in the water were removed at the rate of 53.57%; while adding Ultrasonic at 600W, it decreased at the rate of 73.71%. The removal rate of organics which are in every molecular weight interzones could be 11.73%-39.56% higher than that with the use of pure electrocoagulation, and the removal rate of hydrophilic and hydrophobe organics were improved by 16.67% and 28.30%.6) The removal of dissolved organics with electrocoagulation was combined effects of flocculation, oxidation and the others. The removal rate of the organics, in which the molecular weight was between 1000 dalton and 4000 dalton, 100000 dalton and 0.45μm, was higher than other organics. The Ultrasonic could remarkably enhance the removal effect of the organics in the treatment, which could be explained that ultrasonic might destruct the electrode surface polarization,promot the transfer process, and prevent the anode deposition in electrocoagulation with ultrasonic.