The Study Of Treatment Of Algal In Chaohu Lake By Mechanical Removal And Centrifugal Dewatering

The study proceeded from blue algae bloom frequently break out in importantwater areas of both here and abroad, tried to propose a new type of cyanobacteriabloom governance process on the basis of previous studies,use fixed remove algaefacilities to remove cyanobacteria bloom and dosing Boliye to aid remove cyanob-acteria bloom,use the algae-water separation process of mesh filtering,concentra-ting,decanters dehydrating into algae mud, and finally transported algae mud to theorganic fertilizer plant. The main research contents and results are as follows:(1) Chaohu lake algae as the object, put forward the mechanical removalprocess of floating-fence guide-mechanical removal(assisted mechanical removalby dosing stripping solution). The laboratory test results of dosing Boliye show thatthe best dosing is0.15g/L and has a good removal effect on cyanobacteria blooms,the algae removal rate reached to89.5%, under the dosing the disturbance rejectionis strongest. Characterized the algal flocs after dosing Boliye, and the result showsthat the algae floc formated a very regular space architecture, the role of bridgingand netting is obvious. The expand of test of200m2fence results show that themethod of assisted mechanical removal by dosing stripping solution can rapidly andeffectively remove cyanobacteria blooms in the water,the water of TP, Chla, TNand SS, COD, BOD5drops obviously, water quality improved obvious,the algaeremoval rate as Chla is51%.(2) The algae-water separation process is mesh filtering-concentrating-decanters dehydrating into algae mud, experimental results show that the helicalmesh has a good filtering effect and the filtration efficiency of Chla is66.8%,dosing0.005g/L CP-8750,can get the moisture content of algae residue is95.7%.Obtain the best operating parameters of decanter from test: differentialspeed is3-4r/min,the dosage of flocculant is3.11kg/TDS, the algae mud’s watercontent is89%-90%.(3) The test used the forced ventilation compost for algae mud, after algaemud dryed3d, and composting as the volume ratio of algae mud and rice straw is1:2, after50~60d, The seed germination index can reach above80%, the compostpile compost pile presents a better maturity. The change of Escherichia coli bacterianumber indicates that the high temperature period is the main period to killedpathogenic bacteria. Analysis of organic fertilizer finished product characteristics, such as nitrogen, phosphorus, potassium, organic matter, all targets were achievedthe standard of using.(4)The method aboved has been applied into removing chaohu lake blue algaeduring may to october in2011,which has handled a total of16,000m3of water-richalgae and got970t algal mud and1304t organic fertilizer.totally removecyanobacteria106.7t (dry weight).According to the average content calculating ofremoved cyanobacteria’s total nitrogen and total phosphorus,it’s equal to removing6.25t nitrogen and2.1t phosphorus.Practice has proved that the test process is simple,the price of equipment islow,the harvest of cyanobacterial bloom is large, processing efficiency is high,costis low,could bring benefits of environmental and economic.All these indicate thatwhen blue algae outbreaks in eutrophic lakes,using the method aboved has a veryimportant role in controlling algal blooms pollution,efficiently reducingendogenous nitrogen,phosphorus and other pollutants load.