topic 9: sewage disposal system Flashcards
_____ is the final stage of the plumbing process.
disposal phase
_____ is where used water and
water-carried wastes are brought to various disposal units.
disposal phase
____ is a watertight covered receptacle designed constructed to receive the discharge of sewage from a building sewer, separate solids from the liquid, digest organic matter and store the clarified liquids through a period of detention, and allow the clarified liquids to discharge the final disposal.
septic tanks
What are the 3 substances found inside the septic tanks?
- effluent
- sludge
- scum
_____ is the liquid content of sewage.
effluent
_____ is any solid organic matter that are denser than water and settle at the bottom of the septic tank.
sludge
____ is the lighter organic material that rise to the surface of the water.
scum
What are the 2 types of bacteria in septic tank to encourage decomposition?
- aerobic bacteria
- anaerobic bacteria
_____ relies on oxygen to survive.
aerobic bacteria
____ can survive in places without oxygen.
anaerobic bacteria
The very common bacteria/system used here in the Philippines is the _____.
anaerobic system
Aerobic systems have ______, which is a device that supplies oxygen from the outside into the system.
aerator
What are the minimum dimensions of e two-compartment septic tank?
L = 1500 mm
W = 900 mm
D = 1200 mm
What are the 13 parts of the design phase of the septic tank?
- plans
- quality of design
- materials
- compartments
- manholes
- size of pipe inlet and outlet and their vertical legs
- length and location of inlet and outlet
- vent diameter
- air space
- partition
- structure
- capacity
- location
______ should show all dimensions, reinforcing, structural calculations, and such other pertinent data as needed.
plans
______ shall be such as to produce a clarified effluent of acceptable standards and shall provide adequate space for sludge and scum accumulations.
quality of design
_____ specifies that septic tanks should be constructed of durable materials, not subjected to excessive corrosion or decay, shall be watertight.
materials
Septic tanks are made of cement (most common) or prefabricated cast iron.
materials
Septic tanks have a minimum of _____ compartments.
2
_____ is not less than 2/3 capacity of the total capacity of the tank; not less than 2 cu.m. liquid capacity; shall be at least 0.9m width and 1.5m long; liquid depth not less than 0.6m nor more than 1.8m.
first compartment
_____ has a minimum of 1 cu.m. liquid
capacity.
second compartment
Septic tanks having over 6 cu.m. capacity, the secondary compartment should not be less than ______ in length.
1.5m
Maintain a slope of _____ at the bottom of the digestion chamber to collect the sludge and make it easily accessible from the manhole.
1:10
Septic tanks with at least two manholes, _____ in minimum dimension; one over inlet, other over outlet.
508mm
Septic tanks wherever first compartment exceeds ____ in length, an additional manhole required over the baffle wall.
3.7m
______ diameter size not less than the
sewer pipe.
inlet and outlet pipes
Vertical Legs of Inlet and Outlet Pipes - diameter size not less than the sewer pipe nor less than ______.
104.6mm
Length and location of inlet and outlet shall extend _____ above and at least _____ below the water surface.
101.6mm, 304.8mm
Invert of the inlet pipe shall be at a level not less than ______ above the invert of the outlet pipe.
50.8mm
______ is equal to the cross-sectional area of the house sewer.
vent diameter
To facilitate air space in septic tanks, side walls shall extend _____ above the liquid depth.
228.6mm
Air space in septic tanks - Cover of septic tank shall be at least _____ above the back vent openings.
50.8mm
An inverted fitting equivalent in size to the tank inlet, but in no case less than 104.6mm in diameter, shall be installed in
the inlet compartment side of the baffle with the bottom of the fitting placed midway in the depth of the liquid.
partition (between compartments)
____ baffles are prohibited as partition between compartments of septic tanks.
wooden
The structure of a septic tank shall be capable of supporting an earth load of not less than ______.
14.4 kPa
The ______ of the septic tank is determined by the number of bedrooms or apartment units in dwelling occupancies; by the estimated waste/sewage design flow rate for various building occupancies, whichever is greater.
capacity
The capacity of any one septic tank and its drainage system shall also be limited by the _____ in its drainage field.
soil structure classification
The location of the septic tanks should not be located ______ the house.
underneath
The location of the septic tanks should at least be _____ from the water distribution system.
15 m
What are the 3 degrees/grades of wast water?
- grey water
- black water
- storm water