Experimental Research On Wastewater Treatment Of Marine Exhaust Scrubbing Desulfurization

With the continuous development of international shipping industry, the SOx from ship power device caused serious pollution to the marine atmosphere environment, ship exhaust gas washing desulfurization device is an important technical measures to eliminate SOx pollution, but the waste water washing device in the ship will produce waste water which contains a variety of pollutants, the International Maritime Organization (IMO) on the waste water emission developed a strict limit standard. Because the IMO on the sulfur content of fuel oil Tier III legislation is to be introduced, washing desulfurization wastewater treatment technology research of ship exhaust is very important and urgent.In this paper, research on the wastewater produced by sodium alkali desulfurization of diesel exhaust washing device, in accordance with the IMO requirements for washing wastewater discharge water quality,study on the technology of water treatment.This paper study on water quality of the ship exhaust gas desulfurization washing wastewater, find the main pollutants in the water, after the comparison of treatment methods for each pollutant decided to adopt the method of coagulation air flotation and adsorption of activated carbon were used in treatment of wastewater. First of all, research the suspended solids treatment technology in wastewater, comparison of coagulation sedimentation and coagulation air flotation treatment effect of suspended solids in the wastewater, and study the influence of different factors on treatment of suspended solids. Then, research on treatment technology of polycyclic aromatic hydrocarbons in the wastewater, and verify the activated carbon adsorption of polycyclic aromatic hydrocarbons in waste water. Finally, design of wastewater treatment system according to the above results.This article get the flowing conclusions through research and test: (1) the best formula of coagulant are: aluminum sulfate (60.2%), polymerization aluminum chloride (12.4%), poly ferric sulfate (10.6%), cationic polyacrylamide (2.1%), polysilicate aluminum ferric (14.6%);(2) the best conditions of mixed coagulation sedimentation treatment the suspended solids in the wastewater are: coagulant concentration is 140mg/L, reaction temperature is 30 ?, pH value is 7, stirring speed is 200r/min,stirring time is 70s,the precipitation time is 50min; (3)the best conditions of coagulation floatation treatment the suspended solids in the wastewater are: flotation time is 20min,reflux ratio is 60%,dissolved air pressure is 0.4Mpa, water flow is 0.5m3/h, pH value is 7, coagulant dosage is 110mg/L; (4) the optimum conditions of activated carbon adsorption of polycyclic aromatic hydrocarbons are: activated carbon adsorption time is 90min, the dosage of activated carbon is 5g/L, pH value is 7.5; (5)wastewater treatment system performance can meet mission requirements, quality of treated wastewater can reach IMO emission requirements. According to the test results in this paper,we can draw a conclusion: by using the method of coagulation, air flotation and adsorption of activated carbon can be effective treatment of wastewater,after the treatment of wastewater,the turbidity of wastewater and PAHs concentration meet the IMO standard.The research results of this paper can provide reference for others in their study of the wastewater treatment methods, and support the design of washing water system of ship exhaust gas desulfurization.