Solids, Volatile Dissolved and Fixed Dissolved

Transcription

1 , 8277 Solids, Volatile Dissolved and Fixed Dissolved Gravimetric Method 1 Scope and Application: For wastewater. 1 Adapted from Standard Methods for the Examination of Water and Wastewater DOC Method 8277 Test preparation Before starting the test: The residue from Method 8163 Solids, Total Filterable can be used in this method. Start at Step 12.. Collect the following items: Description Quantity Filter flask 1 Filter holder assembly with stopper 1 Filter, 47-mm, glass fiber 1 Graduated cylinder, 100-mL 1 Tongs 1 Evaporating dish 1 Desiccator with desiccant 1 Analytical balance 1 Muffle furnace 1 Vacuum sourceand tubing 1 Deionized water 1 Steam bath 1 Hot plate 1 See Sample collection, preservation and storage for reorder information. Page 1 of 6

2 Gravimetric Method 1. Heat an evaporating dish at 550 C for one hour. Cool and store the dish in a desiccator until needed. Allow the dish to cool slightly before sealing the desiccator, as pressure from the heated air can force the cover off. 2. Assemble the filter holder/flask assembly using a clean filter flask. All residue should be removed from the flask by cleansing thoroughly with a dilute solution of ammonium hydroxide and rinsing with deionized water. 3. Place a 47-mm filter disc in the filter holder. With vacuum applied to the flask, wash the filter with three separate 20-mL volumes of deionized water. Remove all traces of water by continuing vacuum for two to three minutes after the water has passed through the filter. Disconnect the vacuum and discard these washings from the flask. 4. Reconnect vacuum to the filter holder/flask assembly. Using a clean 100-mL graduated cylinder, filter 100 ml (or more if solids content is low) of a well-mixed representative water sample. For greatest accuracy, filter as much sample as possible. However, using a sample that contains more than 15 mg of solids will clog the filter prematurely. Adjust the exact volume of the water sample to achieve the optimum condition. Several completed tests will show whether any adjustment is necessary. Apply Vacuum 5. Apply vacuum for two to three minutes after the sample has passed through the filter. Disconnect the vacuum. 6. Use tongs to transfer the evaporating dish from the desiccator to the balance. Weigh to the nearest 0.1 mg ( g) and record this weight as A. 7. Place the steam bath on the hot plate, add water and transfer the evaporating dish from the balance to the steam bath. 8. Pour the 100-mL filtrate sample from the filter flask into the evaporating dish. Evaporate to dryness (this may take up to four hours). Periodically check the reservoir of the water bath. Add more water if needed. Page 2 of 6

3 Gravimetric Method (continued) 9. Place the dish in a pre-heated oven at C and dry to a constant weight. This will take minutes. 10. Take the dish out of the oven and allow it to cool to room temperature in a desiccator. Allow the dish to cool slightly in the desiccator before sealing the desiccator, as pressure from the heated air can force the cover off. 11. Use tongs to transfer the evaporating dish to the balance. Weigh to the nearest 0.1 mg ( g). Record this as B. 12. Transfer the dish into a preheated muffle furnace at 550 C for 30 minutes. Repeat Steps Take the dish out of the furnace with tongs and cool to room temperature in a desiccator. Weigh the dish to the nearest 0.1 mg ( g) using an analytical balance. Record this mg value as D. 14. Repeat the ignition (steps 12. and 13.) until two successive weighings do not differ by more than 4% or 0.5 mg, whichever is greater. 15. The loss of weight is total volatile solids. Weighed residue is total fixed solids. Calculate: mg/l Volatile Diss. Solids = ( B D) C mg/l Fixed Diss. Solids = ( A D) C Where: B = Weight (mg) of solids + dish before ignition D = Weight (mg) of solids + dish after ignition C = Volume in ml of filtrate transferred to the aluminum dish A = Weight (mg) of dish Page 3 of 6

4 Sample collection, preservation and storage Summary of method Collect samples in clean plastic or glass bottles. Samples should be analyzed as soon as possible after collection, but can be stored up to seven days by cooling to 4 C (39 F). A well-mixed sample is filtered through a glass fiber filter. An aliquot of the filtrate is evaporated in a weighed dish and dried to constant weight in a C oven. The dish and sample residue are ignited at 550 C for 30 minutes. The loss of sample mass upon ignition represents the volatile dissolved solids. The remaining residue after ignition represents the fixed dissolved solids. Consumables and replacement items Required apparatus Description Unit Catalog number Balance, Analytical, SA80, 115 VAC, 60 Hz each Cylinder, graduated, 100-mL each Desiccant, indicating Drierite each Desiccator, without stopcock each Desiccator Plate, ceramic each Evaporating dish, porcelain, w/lip, 120-mL, 90-mm each Furnace, muffle 120 VAC 50/60 Hz each Furnace, muffle 240 VAC 50/60 Hz each Steam bath, 8 diameter each Tongs each Aspirator, vacuum each Filter disc, 47 mm, glass fiber 100/pkg Filter Holder, 47 mm magnetic each Flask, filtering 1000 ml each Hot plate/stirrer, 7 x 7 inch, 115 VAC each Hot plate/stirrer, 7 x 7 inch, VAC each Oven, laboratory, 120 VAC, 60 Hz each Oven, laboratory, 240 VAC, 50 Hz each Stopper, rubber, one-hole No. 8 6/pkg Water, deionized 4 L Page 4 of 6

5 Optional reagents and apparatus Description Unit Catalog number Dish, aluminum (63 x 17.5 mm) 100/pkg Ammonium Hydroxide, 10% 500 ml Blender,115 VAC, 1.2 L each Blender, 240 VAC, 1.2 L each Bottles, w/cap, wide mouth, 500 ml poly 12/pkg Beaker, glass, 250 ml each 50046H Pump, Vacuum, 1.2 cfm, 115 VAC each Pump, Vacuum, 1.2 cfm, 220 VAC, European plug each Pump, Vacuum, Hand-operated each Stir Bar, 22 x 8 mm each Stirrer, magnetic, 4 x 4, 115 VAC each Stirrer, magnetic, 4 x 4, 230 VAC each Page 5 of 6

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