Design a single cell submerged-flow wetland to treat wastewater from the septic tank at a private residence with 4 people living in a 2-bedroom house. assume a standard water usage rate of 120 gpd/bedroom and a production rate of 0.1 lb bod/person. plan to use gravel with a hydraulic conductivity of 700 ft/day and a slope of 0.22%. use a typical depth of 15" of gravel in your design with a water depth of 12" so that the flow is submerged. follow the example in the reading to complete the following steps: a) calculate the design flow (q) and organic load (ogl) b) select an appropriate surface area if your site is located on the "3.25" line in fig 2 c) determine the best cross-sectional area (compare an and a.) d) calculate the width and length of the wetland (remember to check the l: w ratio) e) sketch the constructed wetland showing the dimensions you calculated