CIVL 111 Water Treatment - Yearly OM Problems 1/ The objective of this project is to utilize, within given constraints, a prototype water filter system to design a full-scale system. The effectiveness of the filter design will be evaluated by the yearly operational and maintenance costs. Group Problem - Treatment Consider a prototype system with the following characteristics: 1. coagulant dosage of mg/l. flowrate 1,000 ml/min 3. run time of 60 minutes 4. inches of anthracite and 4 inches of filter sand. replace filter material once every five years 6. 4 prototype sedimentation tanks Compute the total yearly cost of this system The weight of coagulant (kg) required per gallon of treated water is estimated as: mg 3.8 L kg wt kg c = gal 6 L gallon 10 mg 9.4610 kg gal The number of coagulation and flocculation units, NCF, required are: 0% Factor of Safety NCF 10 (gpd) 10 gpd 6 1. NCF 4.8 or units The total yearly cost of the coagulation and flocculation system for 0 MGD is: $,000 CF year - kg 10 gal 36 days $0.40 9.46 10 gal day year kg $401,30 Step 1 - Compute the prototype sediment tank retention time t p. tp 3 gallon Volumetank 360 in. 1.6 gallons 3 31in. Four tanks are in operation 41.6gallons ml L gallon 1,000 minute 1000ml 3.8 L 3.6 min
CIVL 111 Water Treatment - Yearly OM Problems / Step - The full-scale treatment flowrate Q ST (gpm) per sedimentation tanks is: Step 3 - The effective flowrate Q SE (gpm) in a sedimentation tank is:,000 gallons QST 3,1 gpm 3.6 min Q SE 60 minutes 3,1 gpm 90 minutes,11 gpm Step 4 - The number of full-scaled sedimentation tanks, NS, required to handle the daily volume is estimated as: 0% increase for cleaning 10 gpd day NS 1.,11 (gpm) The operation and maintenance costs per tanks is $3,000/tanks The yearly costs per sediment tank is: $3,000 S 8 tanks tank.8 tanks or 8 tanks $80,000 Step 1 - Convert the average flowrate through the prototype filter (the 3. inch diameter prototype filter has an area of 0.0668 ) into a prototype filter loading rate Q F (gpm/ ). Q F 1,000mL L gallon 1 minute 1,000mL 3.8 L 0.0668 Step - The full-scale treatment flowrate Q FT is: QFT gpm 3.9 1,000 3,9 gpm 3.9gpm /
CIVL 111 Water Treatment - Yearly OM Problems 3/ Step 3 - Considering that each filter is inoperable during backwashing, the effective flowrate Q E is: Step 4 - The number of full-scaled filters NF required to handle the daily volume is estimated as: Q FE 60 minutes 3,9 gpm 90 minutes,63 gpm 0% increase for backwashing 10 gpd day NF 1.,63 gpm 6.3 filters or filters The yearly cost per filter is: The yearly cost for anthracite is: Material replaced every years $,000 F filters filter $,000 FM A $9.0 NF in. 3 1,000 1 in. The yearly cost for filter sand is: FM S $.90 NF 4in. 3 1,000 1 in. $,1 $,3 $4,90 FM Total Treatment System Total Treatment System Total $401,30 $80,000 $,000 $4,90 Coagulation Sedimentation Filtration Filtration Media Total $1,11,
CIVL 111 Water Treatment - Yearly OM Problems 4/ Group Problem - Treatment How would your cost change if you increased your flowrate to 1,100 ml/min and remaining variables were: 1. coagulant dosage of mg/l. run time of 60 minutes 3. inches of anthracite and 4 inches of filter sand 4. replace filter material once every five years. 4 prototype sedimentation tanks The weight of coagulant (kg) required per gallon of treated water is estimated as: mg 3.8 L kg wt kg c = gal 6 L gallon 10 mg 9.4610 kg gal Compute the total yearly cost of this system The number of coagulation and flocculation units, NCF, required are: 0% Factor of Safety 10 gpd 6 1. NCF 10 (gpd) The total yearly cost of the coagulation and flocculation system for 0 MGD is: $,000 CF year - kg 10 gal 36 days $0.40 9.46 10 gal day year kg NCF 4.8 or units $401,30 Step 1 - Compute the prototype sediment tank retention time t p. tp 3 gallon Volumetank 360 in. 1.6 gallons 3 31in. Four tanks are in operation 41.6gallons ml L gallon 1,100 minute 1000ml 3.8 L 1.4 min Step - The full-scale treatment flowrate Q ST (gpm) per sedimentation tanks is:,000 gallons QST 3,493 gpm 1.4 min
CIVL 111 Water Treatment - Yearly OM Problems / Step 3 - The effective flowrate Q SE (gpm) in a sedimentation tank is: Q SE 60 minutes 3,493 gpm 90 minutes,39 gpm Step 4 - The number of full-scaled sedimentation tanks, NS, required to handle the daily volume is estimated as: 0% increase for cleaning 10 gpd day NS 1.,39 (gpm).16 tanks or 8 tanks The operation and maintenance costs per tanks is $3,000/tanks The yearly costs per sediment tank is: $3,000 S 8 tanks tank Step 1 - Convert the average flowrate through the prototype filter (the 3. inch diameter prototype filter has an area of 0.0668 ) into a prototype filter loading rate Q F (gpm/ ). Q F 1,100mL L gallon 1 minute 1,000mL 3.8 L 0.0668 $80,000 4.31gpm / Step - The full-scale treatment flowrate Q FT is: QFT gpm 4.31 1,000 4,31gpm Step 3 - Considering that each filter is inoperable during backwashing, the effective flowrate Q E is: Q FE 60 minutes 4,31 gpm 90 minutes,900 gpm
CIVL 111 Water Treatment - Yearly OM Problems 6/ Step 4 - The number of full-scaled filters NF required to handle the daily volume is estimated as: 0% increase for backwashing 10 gpd day NF 1.,900 gpm. filters or 6 filters The yearly cost per filter is: $,000 F 6filters filter $40,000 Decrease of one filter From 1,000 ml/min flowrate The yearly cost for anthracite is: The yearly cost for filter sand is: FM A FM S Material replaced every years $9.0 NF in. 3 1,000 1 in. $.90 NF 4in. 3 1,000 1 in. $1,900 $,360 $4,60 FM Total Treatment System Total $401,30 $80,000 $40,000 $4,60 Coagulation Sedimentation Filtration Filtration Media Total Treatment System Total $1,13,6 Comparison of Treatment System Flowrate (ml/min) 1,000 1,100 Flocculation $401,30 $401,30 Sedimentation $80,000 $80,000 Filtration $9,90 $44,60 Total $1,11, $1,13,6
CIVL 111 Water Treatment - Yearly OM Problems / Comparison of Treatment System Comparison of Treatment System What if we plotted the cost of the system for various coagulant dosages and flowrates? What would you expect? Flowrate Any questions?