Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

(5) The following is from a laboratory test to determine the various solids conc

ID: 848740 • Letter: #

Question

(5) The following is from a laboratory test to determine the various solids concentration of a sample of untreated wastewater. A 100 mL sample is filtered through a filter pad that removes all the suspended solids. The dry and cool weight of the pad and crucible before filtration is 48.3152 g. After filtration, drying at 105C, and cooling. the weight of the crucible, filter pad, and dried solids is 48.6402 g. The dish placed in a furnace at 600C, then cooled. Weight is measured as 48.6315. What is the concentration of total, suspended and volatile solids in the wastewater sample, expressed in mg/L?

Explanation / Answer

Filtration removes all suspended solids. and collects it

Weight before filtration =48.3152g

weight after filtration = 48.6402g

weight of suspended solids= difference of the two weights

                                       =0.3250g

concentration of suspended solid= weight/ volume of waste water

                                               = 0.3250g/100ml

   =325mg/0.1L

   =32.5mg/L                                  

due to heating at high temperature volatile solid will remove

weight of filtrate= 48.6402g

weight after heating=48.6315g

weight of volatile solid= difference of the two weights

                               =0.0087g

concentration of volatile solid= weight/ volume of waste water

                                               = 0.0087g/100ml

   =8.7mg/0.1L

   =0.87mg/L

Concentration of total waste= sum of the two concentration=32.5+0.87 mg/L

                                                                                      =33.37mg/L