1、 Removal of Organic Pollutants from Sewage by Active Sludge Method l Introduction of water pollutionl Active Sludge Methodl Comparison of activated sludge process and the biological membrane method Introduction of water pollution!JOKEWaterOilWhat is water pollutionl Water pollution is the contaminat
2、ion of water bodies .(e.g. lakes, rivers, oceans, aquifers and groundwater). l Water pollution occurs when pollutants are directly or indirectly discharged into water bodies without adequate treatment to remove harmful compounds.Types of water pollutionBy ApplicationDomestic wastewaterIndustrial was
3、tewaterBy IngredientOrganic wasteInorganic wasteSources of pollutantsl Industrial wastewater: The liquid wastes discharged by all kinds of industrial and mining enterprises in the production process , with large, wide, complex composition, toxicity, easy purification, refractory characteristicsl Agr
4、iculture sewage : Mainly from animal waste, pesticides, fertilizersl Domestic wastewater: A variety of wash water in life, containing the organic non-toxic salts, aerobic organic, inorganic salts such as nitrogen and phosphorus contentWater pollution performanceHeavy metal pollutionMercury(Hg)Cadmiu
5、m(Cd)Lead(Pb)Chromium(Cr)EutrophicationBloomsRed TideMarine oil pollutionBayRoute Offshore wellsHeavy metal pollutionHeavy metal pollutionBloomsRed tideMarine oil pollutionl Active Sludge MethodWhat is Activated SludgeActivated sludge is a process for treating sewage and industrial wastewaters using
6、 air and a biological floc composed of bacteria and protozoa.History 1913, UK Edward Ardern and W.T. Lockett Manchester Corporation Rivers Department at Davyhulme Sewage Works Public Health & EnvironmentActivated sludge method Aerobic bio-method: Domestic sewage Industrial wastewater Remove: Dissolv
7、ed or colloidal biodegradable organic matter Some suspended solid matter Inorganic salts class (partially removed)Arrangement & Process Aeration tank Settling tankMixedcultivationcontinuousfermentor(混菌培养连混菌培养连续培养器续培养器)Tyes of plants Package plants Oxidation ditch Deep shaft Surface-aerated basins/la
8、goonsActivated sludge system in ChinaExample of a complete activated sludge treatment system (London)The results Organic pollutants in wastewater obtained the degradation and removal Activated sludge itself to grow and multiply The water to be purifiedPerspectives The survival of the inoculated bact
9、erial strains in activated sludge is the first prerequisite to obtain their degradative activity. Some physiological activities (growth, enzyme-catalysed reactions, plasmid transfer etc.) only take place when a certain number of a bacterial species are present. The influence of aggregating propertie
10、s on bacterial survival, degradation and conjugation capacity in an activated sludge unit has not been investigated in depth so far. Comparison of activated sludge process and the biological membrane methodThe advantages and disadvantages of the activated sludge process For a long time, we take acti
11、vated sludge process to deal with city life wastewater. It is a two-stage biological treatment process ,which is used most widely all over the world.Characteristics of activated sludge process It use the conventional activated sludge process, which has high capital expenditure, high operating cost ,
12、 large energy consumption(能源消耗)and complex management. It is prone to get sludge bulking phenomena(污泥膨胀现象), or the process equipment cant meet the requirements of high efficiency and low consumption. With the sewage discharge standard continuous strictly , the requirements of nitrogen, phosphorus an
13、d other nutrients in sewage discharge become higher. The traditional sewage treatment technology with the function of nitrogen and phosphorus removal mainly raly on activated sludge process .It often need more than one anaerobic and aerobic reactor in series, forming multi level reaction pool. By in
14、creasing the internal circulation to to achieve the aim of phosphorus and nitrogen removal. The cost of infrastructure investment and energy consumption must be increased, and the management become more complex. l Activated sludge process generates a large number of surplus sludge,and the need for s
15、ludge harmless treatment increase investment.Advantages and disadvantages of biological membrane method The biological membrane method is also a common method to deal with city sewage. Compared with the activated sludge process , it has the following characteristicsl The biological film has a strong
16、 adaptability on the change of water quality. The management is convenient, and no expansion sludge.l microorganism depend on the surface of the carrier, some organisms with the long generation time are able to proliferate. Biological species are more abundant, stable, and less excess sludge will be
17、 producted.l It can deal with the sewage with low concentrationDeficiencies of bio film process The bio film carriers increase investment of the system The carrier materials have small specific surface area. Reaction device capacity is limited, and space efficiency is low. Microbial biomass attached
18、 to the solid surface is difficult to control ,and Operating flexibility is not so good oxygen supply is Rely on natural ventilation, it has less oxygen than activated sludge process.so it is easy to generate anaerobic.l Through the comparison and analysis above, how to make the city sewage treatmen
19、t process towards low energy consumption, high efficiency, little residual sludge, most convenient operation and management , as well as the realization of phosphorus recovery and recycling, sustainable development, has become the issues of common concern between the field of sewage treatment at pre
20、sent.l Emergence of new sewage treatment process made the sewage treatment method towards small occupation area, low running cost, less total investment, high automation degree and direction ,and gradually resolve the difficulties in the technology and investment.l Along with the progress of the society, the sewage treatment industry will have greater development.THANKS
