Essay Example on Wastewater is any water that adversely affects the quality of human Health








INTRODUCTION 1 Waste water Wastewater is any water that adversely affects the quality of human health Wastewater is a liquid source of waste from homes commercial properties and industry or agriculture often containing some pollutants from mixing water of different sources Wastewater is often classified as industrial or domestic wastewater In waste water it contains a lot of harmful pollutants liked lead manganese cadmium zinc and so on As known these pollutants are very dangerous when humans or other species consumed or even when exposed to it These will affect human health and kill aquatic organisms Many serious health effects including mutations cancer organ damage and death are caused by violet dye in large quantities Pollution and human health problems will continue to occur without effective actions 2 Waste water treatment Wastewater is a major cause of water pollution Thus wastewater treatment is a very important process to overcome water pollution To remove pollutants adsorption processes are carried out before discharging waste water out to river by many industries This is an effective way to remove contaminants from industrial wastewater

There are two methods of wastewater treatment chemical physical treatment biological treatment Biological waste treatment uses biological and bacterial substances to decompose waste Physical waste treatment carries out some chemical reactions or physical processes for treatment The adsorption process is classified into two kinds of removal techniques continuous and batch processes In batch process the adsorbents can be used up to maximum capacity But it is not suitable for industrial uses because of the continuous and large wastewater producing which require larger areas to put large reservoirs for treatment It is expensive and the processes need a lot of times to run Therefore industrial wastewater treatment mainly uses continuous process 3 CSTR Continuous Flow Stirred Tank a Description of CSTR CSTR is a continuous process used Anaerobic for the digestion of sewage sludge and concentrated wastes aerated lagoon treatment of industrial wastes and stable ponds for municipal and industry wastewater More importantly this is also a part of Activated Sludge treatment for both municipal industrial wastewater This reactor consists of a well stirred tank containing enzymes which are usually immobilized The substrate is pumped continuously into the reactor at the same time as the product is removed If the reactor works in an ideal way the total back mixing and product stream are identical with the liquid phase in the reactor and constant in time Some substrate molecules can be rapidly removed from the reactor while others can remain in substantial periods The residence time distributes for the molecules in the substrate stream The basic characteristic of an ideal CSTR is that the substrate and microbial concentrations are the same everywhere in the reactor An ideal CSTR has completed the mixing back to minimize the substrate concentration and maximize the concentration of the product relative to the final conversion at every point in the reactor the effectiveness factor being uniform throughout

Therefore CSTRs are preferred reactors everything is equal for processes involving substrate inhibition or product activation b Structure of CSTR The rate of mass accumulation in qin dV dt The rate of mass accumulation out qout In which V is the volume of the control volume C is the component s concentration c Advantages of CSTR The CSTR is an easy flexible and cheap reactor that allows simple loading and replacing of catalysts Good mixing properties allow for simple control of the temperature and pH of the reaction and the supply or removal of gases CSTRs tend to be quite large because they need to be mixed well Volume is usually about 5 to 10 times the volume of the immobilized enzyme contained However this has the advantage that there is little resistance to the stream of substrate which may contain colloidal or insoluble substrates as long as the insoluble particles cannot sweep the enzyme from the reactor The mechanical nature of stirring limits the support for immobilized enzymes to non degradable materials that can enter the product stream However small particles about 10 mm in diameter can be used if they are dense enough to stay in the reactor This minimizes the problem due to the diffusion of resistance 4 CSTR with settling and cell recycling a Description CSTR works along with process of Recycle This recycling process involves the simple return of concentrated microorganisms after removed from wastewater by settling or simply by returning the effluent to the flow of influent in the reactor They recycled back at a flow rate Qr and introduced back into reactor The concentration of microorganisms in this recycle line is X_a r

The concentration in effluent is X_a e rate Qe The concentration of microorganisms of sludge wasting from recycle line is X_a w at flow rate Qw b Structure c Advantage Increased concentration of microorganism in the reactor Increased the volumetric reaction rate Much smaller reactor volume is required biomass is captured and built up to a much higher concentration than normal CSTR decrease reactor volumn Smaller cost of the settler and recycling system II MATERIALS AND METHODS 1 Material Wastewater From municipal wastewater The main characteristic of this wastewater is the high amount of total ammonia nitrogen contained All collected samples were stored at 4 C after collection until required for analysis CSTR system with settling and cell recycling 2 Methods Select an appropriate volume for a CSTR reactor with settling and recycle to achieve an average 90 percent nitrification of ammonium in a municipal wastewater following biological treatment for BOD removal IV CONCLUSION The average removal efficiency of NH4 N 99 5 is therefore much larger than required providing another level of safety in the design for system In this case as with most actual designs the volume reactor tends to be more governed by the reliability considerations rather than considering the removal efficiency

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