As topic 2 ww flowrates

WASTE WATER FLOWRATES
WASTE WATER TREATMENT, DISPOSAL, REUSE
PART-1
(103)
AKHILESH SHAH
PDIETM - MGLI
AHMEDABAD

OUTLINE
• COMPONENTS OF WASTEWATER FLOW
• WATER USED FOR PUBLIC SUPPLIES
• WASTEWATER SOURCES AND FLOWRATES
• ANALYSIS OF WASTEWATER FLOWRATES DATA
• REDUCTION OF WASTEWATER FLOWS
• MEASUREMENT OF WASTEWATER FLOWS
Akhilesh Shah - WWTDR - 1 (103) - MGLI - Ahmeabad - 2017 2

COMPONENTS OF WASTEWATER FLOW
• DOMESTIC WASTEWATER
RESIDENCES, COMMERCIAL, INSTITUTIONAL, ETC
• INDUSTRIAL WASTEWATER
INFILTRATION– INFILTRATION: LEAKAGE INTO WASTEWATER COLLECTION
SYSTEM, CAUSED BY CRACKS, CORROSION, ROOT INTRUSION, ETC.;
INFLOW: NON-WASTEWATER FLOW DIRECTLY INTO WASTEWATER SYSTEM,
E.G., THROUGH MANHOLES
• STORM WATER

COMPONENTS OF WASTEWATER FLOW
• THREE TYPES OF SEWER SYSTEM
• SANITARY
• DOMESTIC
• INDUSTRIAL
• INFILTRATION/INFLOW
• STORM WATER
• COMBINED

WATER USED FOR PUBLIC SUPPLIES
• ONE OF THE SOURCE OF INFORMATION TO CALCULATE
WASTEWATER SOURCE IS TO KNOW THE SUPPLY FLOWRATES
• MUNICIPAL WATER USE
• DOMESTIC WATER USE
• INDUSTRIAL WATER USE
• PUBLIC SERVICE (FIRE FIGHTING, SYSTEM MAINTENANCE AND
LANDSCAPING)
• UNACCOUNTED FOR SYSTEM LOSSES AND LEAKAGES
http://www.livemint.com/Opinion/97fuaF2aQkO9IjPiPAjMyL/Six-
charts-that-explain-Indias-water-crisis.html

http://www.livemint.com/Opinion/97fuaF2aQkO9IjPiPAjMyL/Six-
charts-that-explain-Indias-water-crisis.html

http://nptel.ac.in/courses/105104102/Lecture%202.htm

DOMESTIC WATER USE
• 1/3RD OF MUNICIPAL WATER
SUPPLY
• RESIDENTIAL AREAS
• COMMERCIAL FACILITIES
(SHOPS AND OFFICES)
• INSTITUTIONAL FACILITIES
(SCHOOLS, HOSPITALS ETC)
• RECREATIONAL FACILITIES
(SWIMMING POOLS,
RESORTS ETC.)
http://www.thehindu.com/features/homes-and-
gardens/how-much-water-does-an-urban-
citizen-need/article4393634.ece

INDUSTRIAL WATER USE
• HIGHLY VARIABLE
http://ficci.in/Sedocument/20188/Water-Use-
Indian-Industry-Survey_results.pdf

PUBLIC SERVICES
• PUBLIC BUILDINGS
• FIRE FIGHTING
• PUBLIC PARKS
• SYSTEM MAINTENANCE

UNACCOUNTED LOSSES
• 10 – 12% IF DISTRIBUTION SYSTEM LESS THAN 25 YEARS OLD
• ELSE 15-30%
• 40-60% ATTRIBUTED TO METER ERROR

14Akhilesh Shah - WWTDR - 1 (103) - MGLI - Ahmeabad - 2017

ESTIMATE WATER CONSUMPTION FROM SUPPLY DATA
MUNICIPALITY SUPPLIES WATER TO 147 SERVICES(OR CONSUMERS)
WITH 2.43 PERSON PER SERVICE. THE TOTAL PRODUCTION AND
CONSUMPTION DATA FOR THREE MONTHS ARE AS FOLLOWS:
Month Production
lit/month
Sales lit/month
Jan 14,14,100 10,33,600
Feb 14,21,000 11,04,300
March 14,07,600 10,86,300
Total 42,42,700 32,24,200
Average 46,116 35,046

VARIATIONS IN WATER USE
FACTORS AFFECTING MUNICIPAL WATER USE:
CLIMATE
COMMUNITY SIZE
DENSITY OF DEVELOPMENT
ECONOMICS
DEPENDABILITY AND QUALITY OF SUPPLY
WATER CONSERVATION
METERED SERVICE

• CLIMATE
CONSUMPTION PATTERN BASED ON TEMPERATURE AND PRECIPITATION.
CONSUMPTION PEAK WHEN IT IS HOT AND DRY.
• COMMUNITY SIZE
AVERAGE PER CAPITA WATER USE AND PEAK RATE OF USAGE
SMALL COMMUNITIES WILL HAVE HIGHER PEAK FLOWS THAN AVERAGE
AND LOWER MINIMUM FLOWS

• DENSITY OF DEVELOPMENT
SINGLE FAMILY HOUSING, CONDOMINIUMS AND APARTMENTS
AFFECTS INTERIOR AND EXTERIOR WATER REQUIREMENTS. EXTERIOR WATER USAGE LESS IN APARTMENTS
THAN IN BUNGALOWS DUE TO REDUCED NEED FOR LANDSCAPING
http://indiaenvironmentportal.org.in/files/Wate
r%20consumption%20patterns.pdf
• Economics
Affluence
Greater usage of water-use appliances such
as washing machines, dish washers etc.

• DEPENDABILITY AND QUALITY OF SUPPLY
DEPENDABLE AND GOOD QUALITY WILL ENCOURAGE ITS USE
POOR PRESSURE OR LIMITED QUANTITY DURING DRY OR PEAK PERIODS
WILL BE LESS USED
EG: BOREWELL VS MUNICIPAL WATER
• WATER CONSERVATION
CUT-BACK DURING DRAUGHT – SHORT TERM REDUCTION
PERMANENT WATER CONSERVATION FEATURES [LOW-FLOW TOILETS, RAIN
WATER HARVESTING].

• METERED SERVICES
WATER METERS WILL INDIRECTLY PREVENTS WASTE OF WATER BY USERS
STOP PILFERAGE

PROPORTION OF WATER AS WASTE
WATER
CONSIDERABLE PORTION THAT DOES NOT REACH SEWER:
• PRODUCT WATER USED BY MANUFACTURING UNITS
• WATER USED FOR LANDSCAPE, IRRIGATION, SYSTEM MAINTENANCE,
EXTINGUISHING FIRES
• CONSUMERS WHOSE FACILITIES NOT CONNECTED TO SEWERS
• UNACCOUNTED LOSSES (LEAKAGES)

PROPORTION OF WATER AS WASTE
WATER
CONSIDERABLE PORTION THAT DOES NOT REACH SEWER:
• PRODUCT WATER USED BY MANUFACTURING UNITS
• WATER USED FOR LANDSCAPE, IRRIGATION, SYSTEM MAINTENANCE,
EXTINGUISHING FIRES
• CONSUMERS WHOSE FACILITIES NOT CONNECTED TO SEWERS
• UNACCOUNTED LOSSES (LEAKAGES)
• APPROX. 60-85% BECOMES WASTE WATER

WASTE WATER SOURCES AND
FLOWRATES
DOMESTIC
• APARTMENT
• LOW RISE
• HIGH RISE
• HOTEL
• INDIVIDUAL RESIDENCE
• TYPICAL RESIDENCE
• LUXURIOUS RESIDENCE
• COMMUNITY HOMES
• HOSTELS

FLOWRATES
INDUSTRIAL FLOW
• LIGHT
• HEAVY
• WET
INFILTRATION/INFLOW
• DEFECTIVE PIPES/JOINTS
• STEADY INFLOW – CELLAR/FOUNDATION DRAINS, COOLING WATER
DISCHARGES
• DIRECT INFLOW – STORMWATER RUN-OFF

FLOWRATES
COMPUTE INFILTRATION/INFLOW BASED ON FOLLOWING DATA:
DRY PERIOD FLOWRATE = 33.8 X 10E6 M3/DAY
WET PERIOD FLOWRATE = 63.4 X10E6M3/DAY
MAXIMUM HOURLY WET-WEATHER FLOW RATE (STORM) = 180 X 10E6 M3/HOUR
MAXIMUM HOURLY WET-WEATHER FLOW RATE (NON-STORM) = 80 X 10E6
M3/HOUR
DETERMINE MAXIMUM HOURLY INFLOW AND IF INFILTRATION IS EXCESSIVE?
[EXCESSIVE INFILTRATION IS DEFINED BY AGENCIES AS RATES OVER 8000 M3/DAY
MM-KM IN SEWER. THE COMPOSITE DIAMETER LENGTH OF SEWER SYSTEM IS 6600
MM-KM].

FLOWRATES
ℎ𝑖𝑔ℎ 𝑔𝑟𝑜𝑢𝑛𝑑 𝑖𝑛𝑓𝑖𝑙𝑡𝑟𝑎𝑡𝑖𝑜𝑛 𝑖𝑠 𝑐𝑜𝑚𝑝𝑢𝑡𝑒𝑑 𝑎𝑠 𝑝𝑒𝑎𝑘 𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒
− 𝑏𝑎𝑠𝑒 𝑑𝑟𝑦 − 𝑤𝑒𝑎𝑡ℎ𝑒𝑟 𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒
𝑖𝑛𝑓𝑖𝑙𝑡𝑟𝑎𝑡𝑖𝑜𝑛 = 𝑤𝑒𝑡 𝑤𝑒𝑎𝑡ℎ𝑒𝑟 − 𝑑𝑟𝑦 𝑤𝑒𝑎𝑡ℎ𝑒𝑟 𝑓𝑙𝑜𝑤𝑟𝑎𝑡𝑒𝑠
= 63.4 − 33.8 = 29.6
𝑚3
𝑑𝑎𝑦
𝑚𝑎𝑥𝑖𝑚𝑢𝑚 ℎ𝑜𝑢𝑟𝑙𝑦 𝑖𝑛𝑓𝑙𝑜𝑤
= 𝑑𝑖𝑓𝑓𝑒𝑟𝑒𝑛𝑐𝑒 𝑏𝑒𝑡𝑤𝑒𝑛 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 ℎ𝑜𝑢𝑟𝑙𝑦 𝑤𝑒𝑡 𝑤𝑒𝑎𝑡ℎ𝑒𝑟 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑑𝑢𝑟𝑖𝑛𝑔 𝑠𝑡𝑜𝑟𝑚
− 𝑚𝑎𝑥𝑖𝑚𝑢𝑚 ℎ𝑜𝑢𝑟𝑙𝑦 𝑤𝑒𝑡 𝑤𝑒𝑎𝑡ℎ𝑒𝑟 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒 𝑤𝑖𝑡ℎ𝑜𝑢𝑡 𝑠𝑡𝑜𝑟𝑚
= 180 − 80 = 100 𝑚3/ℎ𝑜𝑢𝑟

FLOWRATES
.
= 4485 M3/DAY MM-KM
WHICH IS LESS THAN AGENCY REQUIREMENT OF 8000 ,3/DAY MM-KM
AND HENCE, IT IS NOT EXCESSIVE

ANALYSES OF WASTE WATER
FLOWRATES DATA
WHY?
AFFECTS THE HYDRAULIC DESIGN OF COLLECTION AND TREATMENT
FACILITIES
FLOWRATES FOR DESIGN
AVERAGE DAILY FLOW
• 24-HOUR PERIOD ON TOTAL ANNUAL FLOWRATE DATA
• USEFUL TO ESTIMATE PUMP AND CHEMICAL COSTS, SLUDGE SOLIDS
AND ORGANIC-LOADING RATES

FLOWRATES DATA
MAXIMUM DAILY FLOW
• USEFUL IN DESIGN OF FACILITIES INVOLVING RETENTION TIME SUCH
AS EQUALIZATION BASINS AND CHLORINE-CONTACT TANKS
PEAK HOURLY FLOW
• SUSTAINED HOURLY, 24-HOUR PERIOD ON TOTAL ANNUAL FLOWRATE
DATA
• USEFUL IN DESIGN OF INTERCEPTOR SEWERS, WASTEWATER PUMPING
STATIONS, FLOWMETERS, GRIT CHAMBERS, SEDIMENTATION TANKS,
CHLORINE CONTACT TANKS, CONDUITS OR CHANNELS (WILL BE
DISCUSSED LATER IN DESIGN)

FLOWRATES DATA
MINIMUM DAILY FLOW
• USEFUL IN DESIGN OF CONDUITS WHERE SOLIDS DEPOSITION MIGHT
OCCUR AT LOW FLOWRATES
MINIMUM HOURLY FLOW
• SUSTAINED HOURLY, 24-HOUR PERIOD ON TOTAL ANNUAL FLOWRATE
DATA
• USEFUL IN DESIGN OF FLOWMETERS FOR CHEMICAL FEED SYSTEMS.
RECIRCULATION FLOWRATE TO SUSTAIN THE FLOWRATE. PUMPS HAVE
ADEQUATE TURNDOWN TO MATCH THE LOW FLOWRATES.

FLOWRATES DATA
SUSTAINED FLOW
• SUSTAINED FLOW
FOR A SPECIFIED
NUMBER OF
CONSECUTIVE DAYS
BASED ON ANNUAL
OPERATING DATA
• USEFUL FOR SIZING
OF BASINS AND
HYDRAULIC
COMPONENTS

FLOWRATES DATA
STATISTICAL ANALYSIS OF WASTEWATER FLOWRATES
• STEP 1: WHETHER THE DATA ARE DISTRIBUTED NORMALLY OR SKEWED
• STEP 2: IF NORMAL THE STATISTICAL MEASURES USED TO DESCRIBE THE
DISTRIBUTION INCLUDES
• MEAN
• MEDIAN
• MODE
• STANDARD DEVIATION
• COEFFICIENT OF VARIATION
• COEFFICIENT OF SKEWNESS
• COEFFICIENT OF KURTOSIS
• IF SKEWED THEN GEOMETRICAL MEAN AND STANDARD DEVIATION ARE NOTED.

STATISTICAL ANALYSIS OF WASTEWATER
FLOWRATES
STATISTICAL ANALYSIS OF
WASTEWATER FLOWRATES
• STEP 1: DETERMINE
GRAPHICALLY, USING
PROBABILITY PAPER,
WHETHER THE FLOWRATE
ARE NORMALLY
DISTRIBUTED OR SKEWED

FLOWRATES
STATISTICAL ANALYSIS OF
WASTEWATER FLOWRATES
• TERM (N+1) IS USED
INSTEAD OF N BECAUSE
THERE MAY BE AN
OBSERVATION THAT IS
EITHER LARGER OR
SMALLER THAN THE
LARGEST OF SMALLEST IN
THE DATA SET

FLOWRATES
BECAUSE THE DATA FALLS ON STRAIGHT LINE IT COULD BE DESCRIBED BY
EITHER TYPE OF DISTRIBUTION (THE DISTRIBUTION IS NOT SKEWED AND
HENCE NORMAL STATISTICS CAN BE APPLIED)

FLOWRATES
DATA ANALYSIS
SET UP A TABLE AS SHOWN BELOW

FLOWRATES
DATA ANALYSIS
CALCULATE
1. MEAN
2. MEDIAN (THE MIDDLE MOST VALUE)
= 0.912 LIT /WK
3. MODE
=3(MED) – 2(MEAN)
= 3(0.912) – 2(0.919) = 0.898 LIT/WK

FLOWRATES
DATA ANALYSIS
CALCULATE
4. STANDARD DEVIATION
5. COEFFICIENT OF VARIATION
̅
.
.
6. COEFFICIENT OF SKEWNESS
.
. /
.
= 0.152

FLOWRATES
DATA ANALYSIS
CALCULATE
7. COEFFICIENT OF KURTOSIS
HENCE, THE DISTRIBUTION IS SOMEWHAT SKEWED ( = 0.152 VERSUS 0
FOR NORMAL DISTRIBUTION) AND IS FLATTER THAN NORMAL DISTRIBUTION
(AS = 1.78 AS COMPARED TO 3.0 FOR NORMAL DISTRIBUTION)
. /
.
= 1.78

FLOWRATES
DATA ANALYSIS
CALCULATE
8. PROBABLE ANNUAL MAXIMUM WEEKLY FLOWRATE
A. DETERMINE PROBABILITY FACTOR
B. DETERMINE FLOWRATE FROM PRECEDING FIGURE AT 98.1 PERCENTILE =
1.14 LIT/WK
THE STATISTICAL DATA IS IMPORTANT TO ESTABLISH DESIGN CONDITIONS
OF WWTPS. THE APPLICATION WILL BE SEEN IN TOPIC 5.

REDUCTION OF WASTE WATER FLOWRATES
OBJECTIVE IS TO CONSERVE WATER AND REDUCE WASTE WATER GENERATION
VARIOUS WATER-CONSERVING DEVICES HAVE BEEN USED.

ESSENTIAL READINGS / REFERENCES
• WASTEWATER ENGINEERING – TREATMENT DISPOSAL REUSE –
METCALF & EDDY, INC. GEORGE TCHOBANOGLOUS. TATA MCGRAW-
HILL PUBLISHING CO. LTD, NEW DELHI

As topic 2 ww flowrates

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