6. 7. T Is UV disinfection more likely to be used by drinking water utilities that use groundwater or surface water sources? Explain your answer. Hint: are viruses, protozoa, or bacteria more of a concern with groundwater or surface water? 8. L Treatment facilities have multiple ion exchange resin present in series. Why? A desert community pumps groundwater from an aquifer that contains a hazardous amount of arsenic. The community has no alternative water sources. List at least two advantages and disadvantages of using reverse osmosis for this application relative to ion exchange.

Civil Engineering For each of the following environmental pollution scenarios, identify TWO PHASE partitioning processes that could be important:a. A leaking underground storage tank full of diesel fuel.b. A lake fed by a spring that flows from groundwater in contact with an aquifer enriched with arsenic sulfide minerals.c. A naturally occurring methane seep that discharges into a muddy pond.d. Hydrochloric acid spill in a limestone-lined lake.

Calculate a risk-based groundwater standard (in ppb) for the chemical 1,2-dichloroethane for a residential homeowner where the person’s well used for drinking water is contaminated with 1,2-dichloroethane. Assume the risk is for an average adult who weighs 70 kg. The state where you work has determined that an acceptable risk is one cancer occurrence per 106 people. Use the values for route of intake, exposure frequency, exposure duration, and averaging time provided for residential use in the following table 6.14. Assume an oral slope factor for 1,2-dichloroethane of 9.2x10-2 per (mg/kg)/day.

A water quality analysis of a well water used for drinking water in a rural home found an arsenic concentration of 0.5 micromolar. This value seems very small to you. But you need to see if it still exceeds the drinking water standard of 10 ppbm. Is the well water violating the standard (and therefore the water would require treatment)?

Please choose the correct answer: 1. In water cycle, ______ brings H2O from water in a lake to vapor at atmosphere. A. evaporation; B. evapotranspiration; C. precipitation;            D. infiltration 2. A drinking water well in NJ is seriously polluted due to saltwater intrusion. The major pollutant is _____. A. Oxygen demanding materials;     B.salts;           C. nutrients;                  D. toxic heavy metals 3. The real reason to cause saltwater intrusion is the different of _____ between freshwater and seawater. A. density;             B. temperature;   C. velocity;     D. all of the above 4. Which of the following represents a non-point pollution source? A. Leaking underground gas tanks;  B. CSO; C. urban runoff;            D. an outlet of untreated industrial wastewater into a river

QUESTION 2 Supposing you were part of the students who visited Barekease water treatment plant for a practical session during the semester in Kumasi. During the session, you had face to face interaction with the Water Engineer in charge of the chemical treatment unit a.) Discuss four (4) key factors that affect the selection of a disinfectant ) Examine five factors that influence disinfection efficacy and microbial inactivation ) A dual media filter is composed of 0.30 m anthracite (mean particle size 0.20 mm) that is placed over a 0.60 m layer of sand (mean particle size 0.70 mm) with a filtration rate of 9.78 m/h. Assume the grains sphericity ф= 0.75and porosity (ε)=0.40. Determine the head loss in the clean filter?

A shit flow diagram (SFD) is a graphic that is used to understand and communicate how excreta physically flows through a city or town. SFDs track both wastewater (WW) and faecal sludge (FS). As a result, they can be used to track the environmental and health impact of sanitation in different communities, regardless of whether the said communities use sewer or non-sewer sanitation systems. Figure 1 (below) shows an SFD for a large town in Mpumalanga. Of particular interest, from the figure, are the FS and WW flows from three communities: CA, CB, and CC. Assuming that (i) at the “local level”, the bulk of faecal matter from CC is quickly incorporated into the soil and that (ii) the direction in which groundwater and surface water flows is from the locality of CC towards the Mfulamkhulu River, which community is likely to have the most impact on the physical and the microbiological quality of the Mfulamkhulu River?Please explain your choice using no more than five sentences. Do you…

You are the Water Sanitation Engineer for Waterbury. Levels of bacterial cells in the water supply must be undetectable, which, in terms of the equation, is <1 per mL of drinking water. A single addition of chlorine yields a log kill every 5 minutes.  During a storm, levels in the incoming water reach 10,000/mL. You hold the incoming water in a treatment tank and give it a single hit with chlorine. If you add the chemical at 10 a.m., when will it be safe to open the valve and release that water for drinking?  (Recall that 10 raised to the 0 power is 1.)

How does the Land surface and near-surface contaminants can cause pollution of surface bodies of water (lakes, streams, etc.) via overland flow?

The Philippine Toxic and Hazardous Wastes Act places limits on the quantities of toxic substances thatmay be discharged into the sewerage system. Guidelines on hexavalent chromium (Cr6+) limits the dischargeamount to just 0.50 mg/L. If an industry dumps hexavalent chromium in the form of potassium dichromate(K2Cr2O7), what is the maximum allowable concentration of hexavalent chromium in % by volume and molesper liter of sewage water? Molar Mass: Cr=52, K=39.1, O=16