1. WASTEWATER

2. Waste Water Lecture Outline Health Effects of wastewater/human waste
Methods of proper disposal: individual , municipal; privies, septic tanks, etc
Disposal methods for developing countries
Municipal treatment plants
steps : screen- primary settling-aeration-secondary settling-disinfection-discharge
Sludge treatment and reuse/Biosolids

3. DISPOSAL OF HUMAN WASTE
Objectives:
Prevention of human waste coming in contact with humans, animals and food
Prevention of insect breeding.

4. Prevention of water pollution, shellfish, bathing areas, soil and air.
Adherence to local, national and international standards

5. Field Disposal Methods of Human Waste
Latrines are constructed to prevent food , soil and water contamination. They should be located at least 100 meters down stream from the water source,
And down wind from residential areas.
At least 5 meters above the water table

6. METHODS OF COLLECTION, TREATMENT AND DISPOSAL
Pit privies
Burn-out Latrine
Cathole latrine
Trench Ltrine
Masonary vault privy
Pail or can privy
Chemical toilet

7. METHODS OF COLLECTION, TREATMENT AND DISPOSAL
Septic Tanks
Public Treatment plants

8. Self Contained Composting Toilet

9. Individual Latrines Cathole 6x6X6 inches hole. Cover after use.
About 200 feet away from any water source

11. Field Latrines

12. PIT LATRINE

13.                                                                    
HOW TO BUILD LATRINE

14. Select Location Dig a hole Select location at least
100 ft. from the water source
It is preferable to have the
location down the stream
or down hill from the
water source
Dig a hole
Mark a three foot diameter
circle using 1.5 ft. string tied
to a stick or nail
Dig a 10 ft. hole and try to
keep the side straight

15. Line the hole Line the hole with bricks or stones leaving two
inch gaps in between
The lining should extend
about four inch above
the ground to form a collar
for the concrete slab to fit on top
Measure the collar to form
a concrete slab to fit on top
of it
Form your concrete slab with two
holes one for squatting and
the other to fit a vent over it

16. Build Superstructure Install the slab on top of the collar
Build up the wall around the slab
To a height of 8 feet.
The squatting hole will be inside
the wall while the vent hole is outside
Fit a cover on top of the wall
Construct a vent with a fly
screen around the vent hole

35. Chemical toilet

36. Tulane/ENHS 641

37. THE SEPTIC TANK

43. Tank Capacity and Dimensions (Add 250 gallons per additional bedroom)
Number
Bed rooms
Min.size
TankReq’d
(Gallons)
Tank Dimension (inside) W L D 1
500
2’9”
6’1”
5’0” 2
750
3’3”
8’0” 3
900
3”9”

44. SCHEMATIC OF SEPTIC TANK

45. SEPTIC TANK
FLOATING SCUM
LIQUID
SLUDGE
INSPECTION PORT
INLET
OUTLET

46. SCHEMATIC OF SEPTIC TANK

71. Public Sewage Treatment Plants
Screens
Grit chambers
Primary settling
Secondary treatment:
*Activated sludge and
*Trickling Filters.
Final settling
Disinfection
Disposal

72. BOD > 220,000 Biochemical Oxygen Demand
Basically is an indication of how much putrescibie organic material
is present in the water or wastewater
Low BOD indicating good water quality and a high BOD reflecting
polluted conditions
POLLUTANT
5-day BOD (in mg/l)
Raw sewage
150 – 250
Cannery waste
5000 – 6000
Discharge from pulp mills
10,000 – 15,000
Wastewater from wool scouring treatment plant effluent
> 220,000

73. Sewage Treatment Plant
Primary
Settling
Tank
Trickling
Filter
Bar
Screen
Grit
Chamber
Pump
Secondary
Settling
Tank
Sludge
Digester
Raw sewage from sewer
Chlorination
(Disinfection)
Discharge

74. FLOW DIAGRAMTRICKLING FILTER SEWAGE TREATMENT PLANT
Screening
Grinding
Primary
Settling
Trickling
Filter OR
Activated
Sludge
Secondary
Settling
Raw
Sewage
Grit
Chamber
Coarse
Screen
Liquid
Secondary sludge return
to primary settling
Sludge
Chlorination
Anaerobic
Digestion
Sludge
Conditioning
To receiving water
Final disposal of digested dried sludge
Sludge
Drying

75. Public Wastewater Treatment Plant

77. Waste Stabilization Ponds/Oxidation Ponds
INLET CHAMBER
AERATOR
OUTLET CHAMBER
8’ to 12’
SCREEN
Pond loading , 15 to 35 lb of BOD/acre/day
Detention time , 90 to 180 days
Liquid depth , 5 ft plus 2 ft freeboard
Embankment , top width 6 to 8 ft; inside outside slope 3 horizontal to 1 vertical.
Pond bottom , level. Impervious, no vegetation
Inlet , 4 in. diameter minimum. At center of square or circular pond
Outlet , 4 in. minimum diameter, controlled liquid discharge using baffles, elbow or tee
fitting.

79. Stabilization Ponds/Oxidation Ponds
Advantages:
Inexpensive to build, operate and maintain
Effluent can be applied to non crop fields without disinfection.
Appropriate method of disposal of human waste in warm climates.
Can be used for fish propagation

80. Disadvantages: Good for small communities of < 2000
Does not function well in cold climates
Requires disinfection if effluent is discharged in a receiving water body such as streams
Aquatic plants overgrowth such as Algae blooms, Duckweed, which might cause it to become anaerobic.

81. Reuse of Human Waste BIOGAS
* If human excreta is combined with animal and agricultural
wastes, and water, it will give off gas as it decomposes.
* Biogas plants typically store the wastes for about 30 days.
This removes some of the pathogenic organisms but by no
means all.

82. Recycling of Treated Human Waste
Effluent: (Liquid)
Treated, disinfected, waste water : irrigation for non-crop fields
Bio-solids: about 5.3 billion pounds are produced in the US annually
Bio-gas generation
Charcoal production
Land application: it is much cheaper than incineration or landfills.
Saves landfill space
It protects water quality,
Supply nutrients to plants/Increases crop production
Reduces soil erosion