Question: What contaminants remain in wastewater treatment after primary sedimentation? What is the effect of discharging organic materials into a receiving water? How can biological treatment methods be classified? Write a general equation to illustrate the decomposition of organic matter by aerobic microorganisms. List four types of aerobic wastewater treatment systems. What is BNR and how is it significant in wastewater treatment? Explain the differences between heterotrophs and autotrophs in terms of their needs. List the factors that affect biological growth of microorganisms. Draw a diagram to illustrate the activated sludge process. What is meant by 'food: mass' ratio? Sketch the growth curves for biomass and viable bacteria in a pure batch culture. Label the main phases. Describe the biological processes in a trickling filter. Briefly describe the main components of a trickling filter. Illustrate with a sketch. What are the advantages and disadvantages of an activated sludge system compared with a trickling filter? What is the purpose of recirculation in a trickling filter? What is meant by a biological tower? What are the advantages and disadvantages of plastic media compared to stone media? What are some operational problems with trickling filters? What is meant by 'activated' sludge- how did the term arise? State the formula for 'food: mass' ratio for an activated sludge tank. What is the significance of sludge settleability? How does extended aeration vary from conventional activated sludge? Need Assignment Help?