septic tank Flashcards
receptacle or vault used to collect organic waste discharged from the house sewer
septic tank
main function: is to liquefy and precipitate solid waste and purifying odorous materials
septic tank
- solid matter is reduced in sizes and consequently changed in character
- sewage that was discharged into the tanks is retained
Digestion
_* during its retention period, about 60% to 70% of the suspended solid of the sewage is removed largely by sedimentation to form a semi-liquid substance called ________
𝐬𝐥𝐮𝐝𝐠𝐞
- The sludge accumulates at the bottom of the septic tank. Parts of the solids are formed into __________. Both the scum and the sludge are processed by anaerobic bacteria and transforming them into liquid and gases.
𝐬𝐜𝐮𝐦
- septic tank therefore combines two processes
𝐬𝐞𝐝𝐢𝐦𝐞𝐧𝐭𝐚𝐭𝐢𝐨𝐧
𝐚𝐧𝐚𝐞𝐫𝐨𝐛𝐢𝐜 𝐝𝐞𝐜𝐨𝐦𝐩𝐨𝐬𝐢𝐭𝐢𝐨𝐧
upper portion of the tank
𝐬𝐞𝐝𝐢𝐦𝐞𝐧𝐭𝐚𝐭𝐢𝐨𝐧
accumulated sludge at the bottom
𝐚𝐧𝐚𝐞𝐫𝐨𝐛𝐢𝐜 𝐝𝐞𝐜𝐨𝐦𝐩𝐨𝐬𝐢𝐭𝐢𝐨𝐧
Decomposition of organic matter from human waste is a bacteriological processed caused by
- aerobes
- anaerobes
- facultative bacteria
Aerobic bacteria
life is in the presence of oxygen
aerobes
Anaerobic bacteria
functions in the absence of free oxygen
anaerobes
can function even with or without the presence of oxygen
facultative bacteria
These three types of bacteria have no relation to disease, they thrive naturally in sewage, and will function when condition are favorable in terms of;
Food supply
Temperature
Moisture
However even in favorable condition, these bacteria ceased to exist due to the presence of;
Antiseptic or disinfectant
large amount or volume of oil
Large amount or volume of grease
The human waste or excreta are decomposed, until the organic matters are transformed into materials that could no longer be utilized by the bacteria in their life process. The process of 𝒅𝒆𝒄𝒐𝒎𝒑𝒐𝒔𝒊𝒕𝒊𝒐𝒏 is regarded as
𝒔𝒕𝒂𝒃𝒊𝒍𝒊𝒛𝒂𝒕𝒊𝒐𝒏
caused by anaerobic bacteria (putrefaction): accompanied by bad odor
aerobic decomposition: not accompanied by unpleasant odor
Decomposition
accompanied by bad odor
anaerobic bacteria (putrefaction)
not accompanied by unpleasant odor
aerobic decomposition
not less than 2/3 capacity of the total capacity of tank
not less than 2 cum liquid capacity
shall be at least 0.9 m width and 1.5 m long
liquid depth not less than 0.6 m nor more than 1.8 m
First compartment
not less than 2/3 capacity of the total capacity of tank
not less than 2 cum liquid capacity
shall be at least 0.9 m width and 1.5 m long
liquid depth not less than 0.6 m nor more than 1.8 m
First compartment
First compartment
not less than ___________capacity of the total capacity of tank
not less than _________ liquid capacity
shall be at least ______ width and ___ long
liquid depth not less than___ nor more than __
2/3
2 cum
0.9 m / 1.5 m
0.6 m / 1.8 m
maximum capacity of 1/3 total capacity of tank
minimum of 1 cum liquid capacity
In septic tanks having over 6 cum capacity, the secondary compartment should be not less than 1.5 m in length.
maintain a slope of 1:10 at the bottom of the digestion chamber to collect the sludge and make it easily accessible from the manhole
Secondary compartment
Secondary compartment
maximum capacity of _______ total capacity of tank
minimum of______ liquid capacity
In septic tanks having over ______ capacity, the secondary compartment should be not less than _______ in length.
maintain a slope of _______at the bottom of the digestion chamber to collect the sludge and make it easily accessible from the manhole
1/3
1 cum
6 cum / 1.5 m
1:10
water tight receptacle which receives the discharge of a sanitary plumbing system or part thereof, designed and constructed to retain solids, digest organic matter through a period of detention
Septic Tank
to allow the liquids to discharge into the soil outside of the tank through a system of open-jointed sub-surface pipings or a seepage pit meeting the requirements of the National Plumbing Code
Septic Tank
with at least two (2) manholes, 508 mm in min dimension; one over inlet, other over outlet
Wherever first compartment exceeds 3.7 m in length, an additional manhole required over the baffle wall.
Manholes
with at least _______ manholes, ____ in min dimension; one over inlet, other over outlet
Wherever first compartment exceeds _______in length, an additional manhole required over the baffle wall.
two (2)
508 mm
3.7 m
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 ______
104.6 mm
Length and location of inlet & outlet
Shall extend ______ above and at least ___________ below the water surface
Invert of the inlet pipe shall be at a level not less than _____ above the invert of the outlet pipe.
101.6 mm / 304.8 mm
50.8 mm
side walls shall extend 228.6 mm above liquid depth.
Cover of septic tank shall be at least 50.8 mm above the back vent openings
Air space
Air space
side walls shall extend _______ above liquid depth.
Cover of septic tank shall be at least ______ above the back vent openings
228.6 mm
50.8 mm
An inverted fitting equivalent in size to the tank inlet, but in no case less than 104.6 mm 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.
Wooden baffles are prohibited.
Partition (between compartments)
Structure
Shall be capable of supporting an earth load of not less than ____
14.4 kPa
An inverted fitting equivalent in size to the tank inlet, but in no case less than _________ 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.
104.6 mm
Location
- Should not be located ________ the house
- At least ________ from the water distribution system
underneath
15 meters
- For a family of six persons, the minimum tank capacity should be approximately ______ .
1.3 cubic meters
MINIMUM WIDTH
90 CM
MIN LENGTH
150 CM
MIN DEPTH
120 CM
For residential building to serve large number of people, allocate ________ of liquid per person
0.14 to 0.17 cu.m
For small residential house to serve up to 12 persons, the chamber should have a liquid content of not more than ______
2.0 cu.m
For school, commercial and industrial establishments, the volume of the septic tank should not be less than ______ or more than ______ per person
0.057 cu.m/ 0.86 cu.m
