Research On Removal And Inhibition Of Algae By Ultrasound And Algal Residue Final Processing System

Characteristics of eutrophication and water bloom of Pengxi River which was a second-class river in Three Gorges Reservoir area were analyzed, basing on the summary in full of water bloom emergency treatment technology research and application in the paper. The study includes: inhibitive characteristics of algae by a fixed ultrasound was systematically investigated in this thesis; multi-functional mobile platform was established, and the optimal effect of algae removal conditions and operating results of the pilot were studied in demonstration bases in Pengxi River. Finally, anaerobic fermentation platform of algal residues that was salvaged by mobile platform were treated into resources. The results show that:Ultrasound can inhibit the growth of algae; Water samples was cultured in the natural state for7ds after ultrasonic treatment, with the irradiation time extend, the effect trends to saturation, the best duration time is 5min. As the ultrasonic frequency increases, the cavitations threshold also increases, cavitations become difficult, low-frequency 20-50 kHz is the optimization. Inhibition can achieve optimal effect by increasing numbers and decreasing the amount of radiation in the case of the same total input energy in the system. The changed biomass of optimal condition ( Y5)and the control group( Y0) every day meet the exponential relationship: y₀ = 0.217y₅^1.092, R² = 0.993. Natural growth of algae in water can be predicted by this relationship, providing warnings for water bloom in advance. Chlorophyll a increased with cell density, there is a consistency when they were treated by ultrasound.Removal and inhibition of algae by Multi-functional mobile platform includes ultrasound systems, JS11-type catamaran system, oxygen aeration system and the algae residue separation system that has a character of low power of ultrasound equipment, rapid response, short duration of action, no secondary pollution and so on. Speed of the multi-functional mobile platform is 16km/h, which can reach the water bloom region quickly in a short time, and the effect is obvious after 5min radiation. After a one-time investment, the actual operating costs are 0.84 yuan / m2 or so,which Can play a better role of demonstration.Effect of the immediate removal of algae by various process parameters of ultrasonic irradiation time, irradiation frequency and radiation from was researched around the Multi-functional mobile platform. In this process, response surface methodology was employed to optimize the various factors. The results show that frequency=20-50 kHz, distance=0.5m, duration time=5min was the best single -frequency conditions for the removal of algae. The effect of chlorophyll has a certain lag, when the exposure time extends to 7min, it can achieve the best removal conditions. Effect on the removal of algae and chlorophyll were increasing by 23.2% and 39.6% respectively after treated by three sets of the same frequency ultrasonic equipment synergistically, but the handling of the economic costs have increased.A special study was employed on the effects of changes of algal toxins in water through direct irradiation by ultrasonic in the paper.It showed that, algae toxin concentrations did not change significantly in 10mins, slightly increased and the volatility was small in the study of changes of algal toxins by ultrasonic irradiation directly in water. By comparing the growth of zooplankton, fish and the submerged plants in the case of ultrasonic irradiation, it also proved that multi- functional mobile platform is secure, will not affect aquatic ecosystems.Technology system of harmless disposal and resource treatment of algal residue was established by innovation on the basis of traditional fermentation and conventional anaerobic fermentation equipment, in connection with the characteristics of algal residue that was salvaged by Multi-functional mobile platform. And the feasibility of the system was evaluated.