Talk:Subsurface flow constructed wetland for greywater
The greywater calculator by Theresa Garrison @Humboldt state is very interesting and well done. One issue I've found with it is the BOD loading estimator. Suppose you select 2 rooms and washing machine. The estimated greywater produced is 120 Gallons. Now, to estimate the BOD loading you check all the boxes from Kitchen sink to Washing machine. The tool calculates the sum of all the BOD loadings, to arrive at 718 mg/L. That's clearly bogus. It should be a weighted average of the BOD loadings of the various sources, weighted by the relative quantity contributed by each source. For example, the kitchen water is estimated at 498 mg/L but there are only relatively few of the 120 gallons that come from the kitchen. They get diluted by the much cleaner bath or shower water.