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ECIV 350 TEST 2 QUESTIONS AND ANSWERS
What affects potability in water? - Answer - Microbes, Organic and Inorganic Chemicals, and radionuclides What percent of the world population does not have access to safe drinking water? - Answer - 40 percent What is the percent of sickness in the world that is caused by inadequate water supply or sanitation? - Answer - 80 percent What are the inorganic chemicals that affect the potability of water? - Answer - Cadmium, copper, lead and mercury What is the goal of potable water? - Answer - To provide water that is palatable and potable What year was US Drinking Water Regulations with the Public Health Services Act? - Answer - 1912 What does Primary Maximum Contaminant Levels include? - Answer - Carcinogenic compounds and Microbial Contamination What does Secondary MCLs focus on? - Answer - aesthetic appeal What are the sources of drinking water? - Answer - Ground water and Surface water Where does groundwater come from? - Answer - shallow and deep wells Where does surface water come from? - Answer - rivers, lakes and reservoirs What are the types of treatment systems? - Answer - limited treatment, coagulation, and softening plants What does limit treatment plants treat? - Answer - high quality water and focus on specific treatment issue in usually groundwater What do coagulation plants treat? - Answer - surface water What does softening plants treat? - Answer - hard waters, usually groundwater What are the primary objectives for a surface water treatment plant? - Answer - remove suspended material such as turbidity and color and eliminate pathogenic organisms.
What are the primary objectives for a groundwater treatment plant? - Answer - remove hardness and other minerals and eliminate pathogenic organisms What technology is used for surface water treatment? - Answer - based on coagulation and flocculation What technology is used for groundwater treatment? - Answer - largely based on precipitation What is the purpose of coagulation? - Answer - to remove turbidity, color and bacteria What promotes aggregation and subsequent gravity settling? - Answer - adding chemicals to neutralize charge of particles What are Colloids? - Answer - Small particles that are negatively charged and considered stable because they repel What are Coagulants? - Answer - tri-valent, non-toxic and relatively inexpensive and insoluble in neutral pH range What are some common coagulants? - Answer - Alum, Ferric Chloride, Ferric sulfate, polyelectrolytes What is the purpose of Jar Testing? - Answer - to simulate the coagulation/ flocculation process in a water treatment plant. What is Rapid Mixing? - Answer - used to blend chemicals (coagulants and water being treated) What is the generally the volume of Rapid Mix Basins? - Answer - 8 meters cubed What is the detention time and depth for Rapid Mix Basins? - Answer - often 10 sec to 5 min and 0.5-1.1 times the basin diameter What is the purpose of flocculation? - Answer - grow flocs to promote gravity settling and slow mixing What is the velocity and detention time of Flocculation? - Answer - the velocity is 0.5- 1.5ft/min and the detention time is at least 20 minutes What equation is used for Coagulation and Flocculation Basins? - Answer - G=sqrt(W/mu) What is the Flocculation Basin Design? - Answer - The design is based on jar test results, using V=Qxt=Qx(theta), use CMFRs
What types of media does Filtration use? - Answer - Single, Dual and multimedia What is single media? - Answer - sand What is dual media? - Answer - anthracite coal and sand What is multimedia? - Answer - anthracite coals, sand and garnet What is rapid sand Filtration? - Answer - used to handle flow with one filter out of service, when filter becomes clogged- headloss increases, turbidity increases How is Backwashing accomplished during rapid sand filtration? - Answer - by forcing water and air up the clearwell back through the filter, then water is retreated or disposed of. What gas is commonly used for disinfection? - Answer - Chlorine What are the design goals of disinfection? - Answer - kill majority of organisms in water and to prevent growth of organisms in distribution system What are important factors in chlorine disinfection? - Answer - Dosage, contact time, turbidity, pH, temperature What is the design of disinfection systems? - Answer - reduction in number of organisms, number of organisms allowed in finished water, contact time, residual chlorine What equation is used for disinfection? - Answer - Chick's law What is the significance of wastewater contaminants? - Answer - Suspended solids, biodegradable organics, pathogens, nutrients, heavy metals, refractory organics, dissolved solids What's the problem with suspended solids? - Answer - causes sludge deposits and anaerobic conditions in the environment What's the issue with biodegradable organics? - Answer - causes anaerobic conditions in the environment What's the problem with pathogens? - Answer - transmit diseases What's the issue with nutrients? - Answer - can cause enthrophication What is the problem with heavy metals and refractory organics? - Answer - toxicity to biota and humans
What is the issue with dissolved solids? - Answer - interfere with reuse What is the pretreatments of industrial Waste-waters? - Answer - to remove materials that will not be treated by municipal system Who monitors industrial wastewater? - Answer - local authorities Who set the requirements for pretreatment for industrial waste-waters? - Answer - US EPA What are the standards for secondary treatment? - Answer - usually depends on BOD, SS, COD and pH What does the municipal waste-water treatment system contain? - Answer - Pretreatment, primary, secondary and advanced treatments What does pretreatment do in an municipal wastewater treatment system? - Answer - removes materials that can cause operation problems, equalization optional What is the primary treatment for MWTS? - Answer - remove ~60 percent of solids and ~30 percent of BOD What is the secondary treatment for MWTS? - Answer - remove ~85 percent of BOD and solids What is advanced treatment for MWTS? - Answer - 95+ percent of BOD, solids, Nitrogen and Phosphorus What does preliminary treatment remove in MWTS? - Answer - removes rags, sticks, floatables, grit and grease What does primary treatment remove in MWTS? - Answer - removal of a portion of the suspended solids and organic matter from wastewater What does Advanced primary treatment remove in MWTS? - Answer - enhanced removal of suspended solids and organic matter from wastewater, accomplished by chemical addition or filtration What does secondary treatment remove in MWTS? - Answer - removal of biodegradable organic matter and suspended solids, disinfection is included What does secondary with nutrient removal treatment remove in MWTS? - Answer - removal of biodegradable organics, suspended solids, and nutrients (nitrogen, phosphorus, or both)
What is a aeration basin? - Answer - organisms convert colloidal and dissolved carbonaceous organic matter to various gases and biomass, competition for food is a critical factor What do microorganisms do? - Answer - create a very rich environment for growth of a diverse microbial community What is the equation that calculates the relationship between nutrients and microorganism growth rate? - Answer - Monod Equation (description of microbial growth What are the effects of Low F/M parameter? - Answer - starved organisms, more complete degradation, larger, more costly aeration tanks, more O2 required, higher power costs, less sludge to handle What are the effects of high F/M parameter? - Answer - organisms are saturated with food, low treatment efficiency What disinfection in primary settling? - Answer - last step in secondary treatment to kill microorganism in effluent, WW held in basin for 15 minutes, used chlorine gas What does Advanced treatment involve? - Answer - membrane filtration, carbon absorption, phosphorous removal, nitrogen removal, ammonia stripping
