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CWEA GRADE 1 LAB ANALYST EXAM 2025/ 2026 ACTUAL
EXAM 200 QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES AGRADE|| LATEST EXAM!!!
Analysis procedure of total solids - ANSWER-1. Choose sample
volume that will yield residue between 2.5 and 200 mg
2. Dry evaporated sample for 1 hour in 103-105 degree C oven
3. Cool in desicator and weigh to constant weight
Constant weight for total solids - ANSWER-Weight change is less
than 4% of previous weight or 0.5 mg
Total Dissolved Solids - ANSWER-A well mixed sample is filtered
through standard glass fiber filter and filtrate is evaporated to
dryness in weighed dish and dried to constant weight at 180
degrees C
Preparing glass fiber filter disk - ANSWER-Apply vacuum and
wash disk with 3 successive 20 mL volumes of reagent grade
water
Preparing evaporating dish for TDS - ANSWER-If volatile solids,
Ignite cleaned evaporating dish at 550 for 1 hour in furnace
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If only TDS, heat cleaned dish to 180 for 1 hour
Analysis procedure of total dissolved solids - ANSWER-1. Stir
sample with magnetic stirrer and pipet measured volume onto
glass fiber filter with applied vacuum
2. Wash with 3 successive 10 ml volumes of reagent grade
water
3. Suction for 3 minutes after filtration is complete
4. Transfer total filtrate to weighed evaporating dish and
evaporate to dryness
5. Dry evaporated sample for 1 hour in 180 +/- 2 degree C
6. Cool and weigh to constant weight
Total Suspended Solids - ANSWER-A well mixed sample filtered
through weighed standard glass fiber filter and residue retained
is dried to constant weight at 103-105 degrees C
Analysis procedure of total suspended solids - ANSWER-1. Wet
filter to seat it
2. Pipet measured volume to filter
3. Wash filter with 3 successive 10 mL wash of reagent grade
water and continue suction for 3 minutes
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4. Dry for 1 hour in 103-105 degree C oven
5. Cool in desicator and weigh until constant weight
Coliform density using fermentaion techniques can be
estimated using - ANSWER-Most probable number table
Drinking water set up - ANSWER-- 10 replicate tube each
containing 10 mL
- 5 replicate tubes containing 20 mL
Objective of total coliform test - ANSWER-Determine the
efficiency of treatment plant operations and integrity of the
distribution system
Nonpotable water for multiple tube fermentation - ANSWER-
Inoculate series of tubes with appropriate decimal dilutions of
water (multiples of 10 mL)
Presumptive phase of Standard total coliform fermentation
technique - ANSWER-- Use lauryl tryptose broth
- Add dehydrated ingredients, mix, heat to dissolve
CWEA GRADE 1 LAB ANALYST EXAM 2025/ 2026 ACTUAL
EXAM 200 QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES AGRADE|| LATEST EXAM!!!
Analysis procedure of total solids - ANSWER-1. Choose sample
volume that will yield residue between 2.5 and 200 mg
2. Dry evaporated sample for 1 hour in 103-105 degree C oven
3. Cool in desicator and weigh to constant weight
Constant weight for total solids - ANSWER-Weight change is less
than 4% of previous weight or 0.5 mg
Total Dissolved Solids - ANSWER-A well mixed sample is filtered
through standard glass fiber filter and filtrate is evaporated to
dryness in weighed dish and dried to constant weight at 180
degrees C
Preparing glass fiber filter disk - ANSWER-Apply vacuum and
wash disk with 3 successive 20 mL volumes of reagent grade
water
Preparing evaporating dish for TDS - ANSWER-If volatile solids,
Ignite cleaned evaporating dish at 550 for 1 hour in furnace
,2|Page
If only TDS, heat cleaned dish to 180 for 1 hour
Analysis procedure of total dissolved solids - ANSWER-1. Stir
sample with magnetic stirrer and pipet measured volume onto
glass fiber filter with applied vacuum
2. Wash with 3 successive 10 ml volumes of reagent grade
water
3. Suction for 3 minutes after filtration is complete
4. Transfer total filtrate to weighed evaporating dish and
evaporate to dryness
5. Dry evaporated sample for 1 hour in 180 +/- 2 degree C
6. Cool and weigh to constant weight
Total Suspended Solids - ANSWER-A well mixed sample filtered
through weighed standard glass fiber filter and residue retained
is dried to constant weight at 103-105 degrees C
Analysis procedure of total suspended solids - ANSWER-1. Wet
filter to seat it
2. Pipet measured volume to filter
3. Wash filter with 3 successive 10 mL wash of reagent grade
water and continue suction for 3 minutes
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4. Dry for 1 hour in 103-105 degree C oven
5. Cool in desicator and weigh until constant weight
Coliform density using fermentaion techniques can be
estimated using - ANSWER-Most probable number table
Drinking water set up - ANSWER-- 10 replicate tube each
containing 10 mL
- 5 replicate tubes containing 20 mL
Objective of total coliform test - ANSWER-Determine the
efficiency of treatment plant operations and integrity of the
distribution system
Nonpotable water for multiple tube fermentation - ANSWER-
Inoculate series of tubes with appropriate decimal dilutions of
water (multiples of 10 mL)
Presumptive phase of Standard total coliform fermentation
technique - ANSWER-- Use lauryl tryptose broth
- Add dehydrated ingredients, mix, heat to dissolve
