Sanitary Drainage System PDF

TOPIC 4 Sanitary Drainage System ENGR. RHODORA A. BUSTAMANTE INSTRUCTOR  C o m p o n e n t s WATER DISTRIBUTION SYSTEM FIRE PROTECTION SYSTEM PLUMBING FIXTURES SANITARY DRAINAGE SYSTEM STORM DRAINAGE SYSTEM FUEL GAS PIPING SYSTEM SANITARY DRAIN...

TOPIC 4 Sanitary Drainage System ENGR. RHODORA A. BUSTAMANTE INSTRUCTOR  C o m p o n e n t s WATER DISTRIBUTION SYSTEM FIRE PROTECTION SYSTEM PLUMBING FIXTURES SANITARY DRAINAGE SYSTEM STORM DRAINAGE SYSTEM FUEL GAS PIPING SYSTEM SANITARY DRAINAGE SYSTEM  Sanitary Piping Layout General Rules in designing the Sanitary system: The pipes should take the shortest possible route to the house sewer or the terminating point of the Sanitary system Control components such as clean-outs, traps, and vents, should be located strategically so as to ensure efficient circulation Subsystems of the Sanitary System: Waste Collection System Ventilation System  Essential Parts of the Sanitary Drainage System Waste Pipe conveys only wastewater or liquid waste free of fecal matter. Vent Pipe used for ensuring the circulation of air in a plumbing system and for relieving the negative pressure exerted on trap seals. Trap a fitting or device designed and constructed to provide, when properly vented, a liquid seal which prevents the backflow of foul air or methane gas without materially affecting the flow of sewage or wastewater through it. Stack the vertical main of a system of soil, waste or vent pipings extending through one or more stories and extended thru the roof. Branch any part of the piping system other than a main, riser or stack.  Essential Parts of the Sanitary Drainage System House/Building Drain part of the lowest horizontal piping of a plumbing system which receives the discharges from the soil, waste and other drainage pipes inside of a building and conveys it to the house sewer outside of the building. House/Building Sewer extends from the house drain at a point 0.60 meters from the outside face of the foundation wall of a building to the junction with the street sewer or to any point of discharge, and conveying the drainage of one building site. NPC 203.3  Principles of Waste & Soil (EXCRETA) Pipes Roughing-in CHANGES IN DIRECTION OF SANITARY DRAINAGE LINES Horizontal to Horizontal change in direction use 45° wye branches, combination wye – 1/8 bend branches, or other approved fittings of equivalent sweep Vertical to Horizontal change in direction 45° wye branches or other approved fittings of equivalent sweep  Principles of Waste & Soil (EXCRETA) Pipes Roughing-in Horizontal to vertical change in direction use 45° or 60° wye branches, combination wye -1/8 bend branches, sanitary tee or sanitary tapped tee branches, or other approved fittings of equivalent sweeps. No fitting having more than one inlet at the same level shall be used (i.e., sanitary cross) Double sanitary tees may be used when the barrel of the fitting is at least two pipe (2) sizes larger than the largest inlet, (pipe sizes recognized for this purpose are 51, 64, 76, 89, 102, 114, 127, & 152 mm dia.)  Sanitary Drainage Lines UNIT OF MEASUREMENT OF SIZES OF SANITARY DRAINAGE LINES The size of waste pipes or soil pipes depend on the amount of waste it carries. A lavatory discharges 0.47 liters/sec or 28.3 liters/min (7.5 gallons per min or 1 cu ft per min), which is equivalent to the Fixture Unit (F.U.) The F.U. rating of plumbing fixtures is based on the size of required trap.  Sanitary Drainage Lines Maximum Trap Loading ITEM NO. PIPE SIZE FIXTURE UNIT Notes: 1 32 mm 1 1.Capacity over 3.15 L/s shall be determined by the 2 38 mm 3 Administrative Authority. 2.For a continuous flow into a 3 51 mm 4 drainage system, such as from sump pump or ejector, 4 76 mm 6 air-conditioning equipment or similar devices, two (2) 5 102 mm 8 fixture units shall be allowed Exception: On self-service laundries. for every 0.063 L/s of flow. 3. 1 gpm = 0.063 L/s Discharge Capacity ITEM NO. LITERS/SEC (GPM) FIXTURE UNIT 1 Up to 0.47 L/s (Up to 7.5 gpm) 1 2 0.50 to 0.95 (8 to 15 gpm) 2 3 1 to 1.89 (16 to 30 gpm) 4 4 1.95 to 3.15 (31 to 50 gpm) 6  Sanitary Drainage Lines MINIMUM SLOPE OF SANITARY DRAINAGE LINES Minimum slope or pitch of horizontal drainage pipe – 2% or 20mm/m (¼” per foot). Exception: Where it is impracticable due to depth of street sewer, adverse structural features and irregular building plans, pipes 102 mm dia or larger may have a slope of not less than 1% or 10mm/m (1/8” per foot), approved by the Administrative Authority  Traps & Interceptors Types of Permissible Traps: The Common P-Trap Used for lavatories, kitchen sinks, laundry tubs, & urinals Materials commonly used for the P-trap: nickel, chrome plated brass, Galvanized malleable copper, & PVC. The Deep Seal P-Trap Water seal is about twice the size of The common P-trap Used for extreme conditions because resealing quality is greater  Traps & Interceptors The Stand Trap Used for fixtures such as slop sinks that are usually built low in the ground, leaving very little space for a foundation & a trap Serves as a water seal & structural support for the fixture The Running Trap Used within the line of the house drain  Traps & Interceptors Types of Permissible Traps: The Drum Trap Has a large diameter (around 0.16 m) Used for fixtures that discharge large amount of water (bathtubs, shower or floor drains)  Traps & Interceptors Types of Prohibited Traps: Traps with movable parts or concealed interior partitions No fixtures shall be double-trapped The S-Trap Predecessor of P-traps Used before traps had to connect to a ventilation line  Traps & Interceptors REQUIREMENTS: Traps REQUIRED Each plumbing fixture, except those with integral traps, shall be separately trapped with an approved-type waterseal trap. Only one trap shall be permitted on a trap arm (portion of a fixture drain between a trap and the vent) One trap, centrally located, may serve three single compartment sinks or laundry tubs or lavatories, adjacent to each other and in the same room, where their waste outlets are not more than 0.75 m apart.  Traps & Interceptors SIZE OF TRAPS: The trap shall be the same size as the trap arm to which it is connected. Each fixture trap shall have a trap seal of water of not less than 51 mm and not more than 102 mm (except where a deeper seal is found necessary by the Administrative Authority for special conditions.  Traps & Interceptors Minimum sizes of traps for common plumbing fixtures DRAINAGE ITEM TRAP & TRAP FIXTURE FIXTURE NO. ARM SIZE UNITS 1 Bathtubs 38 mm 2 2 Bidets 38 mm 2 3 Floor Drains 51 mm 2 4 Shower, single stall 51 mm 2 5 Sink (residential) 38 mm 2 6 Urinal, wall mounted, integral trap 51 mm 3 7 Wash Basin (single) 32 mm 1 8 Water Closet (private installation) 76 mm 4 9 Water Closet (public installation) 76 mm 6  Traps & Interceptors INSTALLATION OF TRAPS: The vertical distance between a fixture outlet tailpiece and the trap weir shall not exceed 0.60 m in length. Horizontal Distance of Trap Arms TRAP ARM DISTANCE DIAMETER TO VENT Note: In no case shall 32 mm 0.76 m the trap distance be less than 2 times the diameter 38 mm 1.07 m of the trap arm. 51 mm 1.52 m 76 mm 1.83 m 102 mm & larger 3.05 m The developed length of the trap arm (measured from the top of closet ring to inner edge of vent ) of a water closet or similar fixture shall not exceed 1.8 m. For trap arm 76 mm dia or larger, a cleanout is required for a change of direction of greater than 22 ½ °.  Traps & Interceptors INDUSTRIAL INTERCEPTORS (CLARIFIERS) & SEPARATORS: Interceptors (a device designed and installed to separate and retain deleterious, hazardous or undesirable matters from normal wastes and permits normal sewage or liquid wastes to discharge into the disposal terminal by gravity) shall have a water seal of not less than 152 mm deep. Each interceptor shall be properly vented. Slaughterhouses, packing establishments, and any establishment which discharges wastewater with considerable amount of grease, hairs, feathers , etc. shall drain through a screening device and thence into a grease interceptor. Auto wash racks and/or floor or slabs used for cleaning machinery or machine parts shall be adequately protected against storm or surface water and shall drain into an interceptor which will separate oil and grease before the effluent reaches the public stream.  Clean-outs REQUIREMENTS: Clean-outs REQUIRED at the upper terminal of every horizontal sewer or waste line at each run of piping more than 15 meters (50 feet) in total developed length at every 15 m (50 ft) of total developed length or a fraction thereof additional clean-out shall be provided on a horizontal line with an aggregate offset angle exceeding 135° inside the building near the connection between the building drain and the building sewer or installed outside the building at the lower end of the building drain and extended to grade.  Clean-outs Clean-outs NOT REQUIRED on a horizontal drain less than 1.5 m in length unless such line is serving sinks or urinals. on short horizontal drainage pipe installed at a slope of 72 deg or less from the vertical line (or at an angle of 1/5 bend)  Clean-outs SIZE OF CLEAN-OUTS: Size of clean-out shall be in conformity with the size of pipe served Clean-Out Size SIZE OF SIZE OF THREADS PIPE CLEANOUT PER 25.4MM 38 mm 38 mm 11-1/2 51 mm 38 mm 11-1/2 64 mm 64 mm 8 76 mm 64 mm 8 102 mm & larger 89 mm 8  Clean-outs INSTALLATION OF CLEAN-OUTS: Each clean-out shall be installed so it opens with the direction of flow or at right angles to the direction of flow except in the case of a wye branch. Each 90° clean-out extension shall be constructed from a wye fitting or an approved fitting of equivalent sweep. Each clean-out 51 mm or less shall have a front clearance of not less than 305 mm; those 51 mm or more shall have a front clearance of 450 mm. Clean-outs in underfloor piping shall be extended to or above finish floor or shall be extended outside the building when there is less than 450 mm vertical clearance or 750 horizontal clearance to the means of access. No underfloor clean-out for residential occupancies shall be located more than 6.1 m from an access door, trap door or crawl hole.  Vents & Venting System VENTILATION Portion of the drainage pipe installation intended to maintain a balanced atmospheric pressure inside the system Vent Pipe- a pipe or opening used for ensuring the circulation of air in a plumbing system and for relieving the negative pressure exerted on trap seals.  Vents & Venting System Main Types: VENTS Main Soil & Waste Vent the ‘backbone’ of the entire sanitary system Connected to the Main Soil & Waste Stack The portion where waste does not travel through Continues to the roof; the portion penetrating the roof is called the Vent Stack Through Roof (VSTR)  Vents & Venting System Main Vent the principal artery of the venting system to which vent branches are connected. a.k.a. ‘Collecting Vent Line’ serves as support to the Main Soil & Waste Vent  Vents & Venting System Individual Vent or Back Vent a pipe installed to vent a fixture trap, that connects with the vent system above the fixture served or terminates in the open air.  Vents & Venting System Other Types: Unit, Common, or Dual Vent an arrangement of venting so installed that one vent pipe serve two (2) traps.  Vents & Venting System Relief Vent a vertical vent line that provides additional circulation of air between the drainage and vent systems or to act as an auxiliary vent on a specially designed system such as a “yoke vent” connection between the soil and vent stacks.  Vents & Venting System Yoke or By-pass Vent a pipe connecting upward from a soil or waste stack below the floor and below horizontal connection to an adjacent vent stack at a point above the floor and higher than the highest spill level of fixtures for preventing pressure changes in the stacks.  Vents & Venting System Circuit Vent a group vent pipe which starts in front of the extreme (highest) fixture connection on a horizontal branch and connects to the vent stack. a.k.a. ‘Loop Vent’ Serves a battery of fixtures  Vents & Venting System Looped Vent a vertical vent connection on a horizontal soil or waste pipe branch at a point downstream of the last fixture connection and turning to a horizontal line above the highest overflow level of the highest fixture connected there Used in spaces without partitions  Vents & Venting System Wet Vent that portion of a vent pipe through which wastewater also flows through.  Vents & Venting System Local Vent a pipe or shaft to convey foul air from a plumbing fixture or a room to the outer air. Dry Vent a vent that does not carry liquid or water-borne wastes.  Vents & Venting System Stack Vent the extension of a soil or waste stack above the highest horizontal drain connected to the stack. Vent Stack the vertical vent pipe installed primarily for providing circulation of air to and from any part of the soil, waste of the drainage system. The uppermost end above the roof has traditionally been referred to as Vent Stack Through Roof (VSTR).  Vents & Venting System REQUIREMENTS: Vents REQUIRED Each trap shall be protected against siphonage and back- pressure through venting. Vents NOT REQUIRED on a primary settling tank interceptor which discharges through a horizontal indirect waste pipe into a secondary interceptor. The secondary interceptor shall be properly trapped and vented. Traps serving sinks in an island bar counter. Such sink shall discharge by means of an approved indirect waste pipe into a floor sink or other approved type receptor.  Vents & Venting System SIZE OF VENTS: The sizes of vent piping shall be determined from its length and the total number of fixture units connected thereto. The diameter of an individual vent shall not be less than 32 mm (1-1/4”) nor less in size than one-half (1/2) the diameter of the drain to which it is connected.  Installation of Vents GRADES & CONNECTIONS All horizontal or branch vents shall be free from drops or sags & shall be graded and connected to drip back by gravity to the drainage pipe it serves. Each vent shall rise vertically 152 mm above the highest level rim of the fixtures served before offsetting horizontally. All vent pipes shall extend undiminished in size above the roof or shall be reconnected to the soil or waste stack vent at a point below the roof. The “vent stack through roof” (VSTR) shall be increased one (1) pipe size above the connection between the stack vent and the horizontal vent. Two (2) fixtures having same level inlet openings, may be served by a common vertical vent pipe connected to an approved double branch fitting.  Installation of Vents VENT TERMINATION VSTR shall terminate vertically not less than 150 mm above the roof nor less than 300 mm from any vertical surface nearby. Each vent opening shall terminate: Not less than 3.00 m from any openable window; Not less than 0.90 m above any openable window; Not less than 0.90 m away from any lot line, alley and street boundary lines. Vertical vent pipes shall extend 3.00 m distant from any part of the roof that is used for human activities and shall extend not less than 2.10 m above such roof.  Installation of Vents VENT STACK & RELIEF VENTS Each soil or waste stack extending ten (10) or more storeys above the building drain shall be served by a parallel vent stack which shall extend undiminished in size from its upper terminal at the roof and connect to the soil or waste stack at ground level and at every fifth floor levels with a “yoke vent” at a point below the horizontal soil or waste branch connection to the stack and at the nearby vent stack above the same floor to provide a relief vent. The size of yoke vent shall be not less in diameter than either the soil stack or the vent stack, whichever is smaller. The yoke vent connection at the vent stack shall be placed 1.0 m above the floor level and, by means of a wye branch at the soil stack, shall be placed below the fixture branch serving that floor.  Vents & Venting System SANITARY SYSTEM PROBLEMS: Trap Seal Loss - Direct effect of the Minus & Plus Pressure inside the system due to inadequate ventilation of traps - Attributed to the following conditions: Siphonage- direct and momentum  Vents & Venting System Back Pressure Capillary Attraction Evaporation- caused by extreme temperatures, idleness Wind Effects- strong winds blow the trap seal Retardation of flow - Due to the effect of atmospheric pressure and/or gravity Deterioration of the Materials - Due to the formation of acids  INDIRECT WASTE PIPING, WET-VENTED SYSTEMS & SPECIAL WASTES Indirect Waste Pipe – is a pipe that does not connect directly with the drainage system but conveys liquid wastes by discharging into a plumbing fixture, interceptor or receptacle directly connected to the drainage system.  House Drain Appliances HOUSE DRAIN APPLIANCES: GREASE TRAPS: For establishments like restaurants, cafes, lunch counters, cafeterias, bars and clubs, hotel, hospital, sanitarium, factory or school kitchens. A grease trap is not required for individual dwelling units. No grease trap shall be installed for a facility that has an approved rate of flow of more than 3.4 liters per second (54.26 gpm) nor less than 1.3 L/s (20.74 gpm). Each grease trap shall have an approved water seal of not less than 51 mm in depth or the diameter of its outlet, whichever is greater. No food waste disposal unit shall discharge into a grease interceptor or grease trap.  House Drain Appliances GREASE TRAPS: Used for fixtures where grease may be introduced into the drainage or sewer system in quantities that can effect line stoppage or hinder sewage treatment or private sewage disposal. 2 Main Types Earth Cooled Grease Trap Mechanical Grease Trap  House Drain Appliances Operating Principles (separation of grease from water): grease suspended in waste floats to the surface Earth cooled Grease Trap Mechanical Grease Trap  Traps & Interceptors Grease Trap Capacity TOTAL # OF REQUIRED GREASE FIXTURES RATE OF RETENTION CONNECTED FLOW CAPACITY 1 76 L/ min. 18 Kg 2 95 L/ min. 23 Kg 3 132 L/ min. 32 Kg 4 189 L/ min. 45 Kg  House Drain Appliances HOUSE TRAPS: Placed in the house drain immediately inside the foundation wall of the building DRAIN TILES: Used to prevent groundwater from seeping through the basement walls & foundation Hollow tiles are placed around the perimeter of the foundation where water is collected; drain tiles are connected to the house drain or sump pit  House Drain Appliances Garage Traps: a.k.a. garage catch basin Operating Principles: trap is filled with water & located at the lowest point of the garage so it can collect all wastes.  House Drain Appliances Back Flow Valves: Used in house drain to prevent the unlikely occurrence of back flows Similar to check valves  House Drain Appliances Sewage Ejectors: Pumps the wastes up form the sump pit to the sewers (which are usually higher than basement levels)  Private Sewage Disposal Systems DISPOSAL PHASE- the final stage of the plumbing process; where used water and water-carried wastes are brought to various disposal outlets Definition: SEPTIC TANKS A watertight covered receptacle designed and constructed to receive the discharge of sewage from a building sewer, separate solids from the liquid, digest organic matter and store digested solids through a period of detention, and allow the clarified liquids to discharge for final disposal SLUDGE- solid organic matter that are denser than water and settle at the bottom of the septic tank SCUM- lighter organic material that rise to the surface of the water EFFLUENT- liquid content of sewage  Private Sewage Disposal Systems Bacteria in septic tank to encourage decomposition: Aerobic bacteria- relies on oxygen to survive Anaerobic bacteria- can survive in places without oxygen  Private Sewage Disposal Systems Minimum dimensions- L= 1500mm W=900mm D=1200mm  Private Sewage Disposal Systems SINGLE CHAMBER SEPTIC TANK:  Private Sewage Disposal Systems DESIGN CRITERIA: PLANS: should show all dimensions, reinforcing, structural calculations, and such other pertinent data as needed. QUALITY OF DESIGN: shall be such as to produce a clarified effluent of acceptable standards and shall provide adequate space for sludge and scum accumulations. MATERIALS: constructed of durable materials, not subject to excessive corrosion or decay, shall be watertight. Material: cement (most common) or pre-fabricated cast iron  Private Sewage Disposal Systems COMPARTMENTS: have a minimum of 2 compartments: 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. Secondary compartment: 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 MANHOLES: 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.  Private Sewage Disposal Systems SIZES OF PIPE INLET & OUTLET & THEIR VERTICAL LEGS: Inlet and Outlet pipes – diameter size not less than the sewer pipe 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 101.6 mm above and at least 304.8 mm below the water surface Invert of the inlet pipe shall be at a level not less than 50.8 mm above the invert of the outlet pipe. VENT DIAMETER: equal to the cross sectional area of the house sewer.  Private Sewage Disposal Systems AIR SPACE: 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. PARTITION (between compartments): 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. STRUCTURE: Shall be capable of supporting an earth load of not less than 14.4 kPa  Private Sewage Disposal Systems CAPACITY: The capacity of septic tanks 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; or by the number of fixture units of all plumbing fixtures; whichever is greater. The capacity of any one septic tank and its drainage system shall also be limited by the soil structure classification in its drainage field. LOCATION: Should not be located underneath the house At least 15 meters from the water distribution system  SEWERS 3 degrees or grades of waste water: Grey Water (or Area Water) Waste water with the exception of human wastes From laundries, wash basins, sinks, tubs, etc. Black Water Water plus solid and liquid human wastes Storm Water Rainwater only  SEWERS CLASSIFICATION OF SEWERS: Combination Public Sewers Oldest variety Carries both storm & sanitary wastes Storm Sewers Sanitary Sewers Carries regular sanitary wastes only Terminates in a modern sewage disposal plant for treatment Built at a depth of 3 meters (tributaries)  SEWERS 2 TYPES OF SANITARY SEWERS: Tributary Sewers Termination points of individual units or structures Usually round shaped, with diameters between 0.60 to 1.2 meters Made of vitrified clay or cement pipes; often installed by the curb line, before the street Normally laid in the Northern or Eastern side of streets with east-west or north-south orientations  SEWERS Intercepting Sewers a.k.a. ‘collecting sewers’ Termination points of tributary sewers Placed much lower in the ground, from 4 to 30 meters in depth Varies in shape but have a diameter or effective opening ranging from 0.60 to 3 meters Sloped at an angle of 1:50 or 2% Lifting stations are placed at certain intervals and pumps or sewage ejectors are used to lift the waste; sewers terminate at the disposal plant  SEWERS REQUIREMENTS: Sewers REQUIRED Drainage pipes of all buildings shall be connected to the public sewer. When not available, they shall be connected to an approved private sewage disposal system. Public sewer may be considered as not being available if it is more than 61 meters from any proposed building or exterior drainage facility. Exception: Single family dwellings with an existing private sewage disposal system may not be connected to a new public sewer when no hazard, nuisance or unsanitary condition is evident and when there is no sufficient grade or fall existing to permit proper drainage flow by gravity to the public sewer.  SEWERS DAMAGE TO PUBLIC SEWER OR PRIVATE SEWAGE DISPOSAL SYSTEM It is unlawful to discharge any ashes, cinders, solids, rags, flammable, poisonous, explosive liquids or gases, oils, grease, and other things whatsoever which would cause damage to the public sewer or private disposal system. No rain, surface or subsurface waters shall discharge into any excreta drainage system. No cesspool and septic tank effluents, seepage pit or under drain system shall be connected to the excreta building sewer leading to a public sewer main. No commercial food waste grinder shall be connected to a private or public sewage disposal system.  SEWERS SIZE OF SEWER: The minimum size of any building sewer shall be determined on the basis of the total number of fixture units drained by such sewer. No building sewer shall be smaller than 150 mm diameter nor less in size than the building drain.  SEWERS INSTALLATION OF SEWER: Building sewers shall be run in practical alignment at a uniform slope of not less than 2% or 21 mm/m toward the point of disposal. Exception: When impractical due to depth of street sewer, structural features or to adverse arrangement of building, to obtain a slope of 2%, sewers 102 mm and 152 mm in dia may have a slope of not less than 1% (10.5 mm/m) and those 203 mm dia and larger may have a slope of not less than 0.5% (5.3 mm/m)  SEWERS No building sewer shall be installed less than 0.6 M from the outer face of any building foundation, nor less than 0.3 M below the finish surface of the ground. Location of building sewer in relation to other services is shown below. 0.60 m from any building or structure 15.2 m from water supply wells 15.2 m from streams 0.30 m from domestic supply pipes 0.30 m from public water main  SEWERS Building sewer or drainage pipe of clay or materials which are not approved for use within a building shall not be laid in the same trench as water pipes unless: the bottom of the water pipe is 0.3M above the top of the sewer pipe (NPC 1208.1.1), the water pipe is placed on a solid shelf excavated at one side of the common trench with a minimum horizontal distance of at least 0.3 m from the sewer or drain pipe (NPC 1208.1.2).  SEWERS Water pipes crossing sewer or drainage pipe of clay or materials which are not approved for use within a building shall be laid a minimum of 0.3 m clear above the sewer or drain pipe. Water pipe joint shall be installed not less than 3 meters away from sewer line in both directions.  Private Sewage Disposal Systems DISPOSAL FIELDS Private sewage disposal system common in rural areas for structures with large adjacent open fields  Private Sewage Disposal Systems AREA: dependent on the required septic tank capacity or estimated sewage flow rate, whichever is greater, and; the type of soil found in the excavation. DISTANCE FROM WATER TABLE: No excavation for leach bed shall extend within 1.5 m of the water table. WITH SEEPAGE PIT: Filter material in the trenches shall terminate 1.5 m from pit excavation and the pipe extending from such points to the seepage pit shall be watertight.  Private Sewage Disposal Systems SEEPAGE PITS a loosely lined excavation in the ground, which receives the discharge of a septic tank; designed to permit effluent to seep through pit bottom and sides CAPACITY: based on the quantity of liquid waste and on the character and porosity of the surrounding soil. SIZE OF SEEPAGE PIT: Circular in shape with excavated diameter of not less than 2.2 m and to be lined with clay or concrete brick.  Private Sewage Disposal Systems STRENGTH: Brick lining shall have a minimum compressive strength of 17225 kPa. MULTIPLE SEEPAGE PITS: served through a distribution box or shall be connected in series by means of a watertight connection. The outlet shall have a vented leg fitting extending 304.8 mm below the inlet fitting.  Private Sewage Disposal Systems CESSPOOLS a non-watertight lined excavation in the ground which receives the discharge of a sanitary drainage system, designed to retain the organic matter but permitting the liquid to seep through the pit bottom and sides  Private Sewage Disposal Systems TEMPORARY PERMITS: Temporary expedient pending the construction of a public sewer, so long as it is established that a public sewer will be available in less than 2 years and the soil and ground water conditions are favorable; As an overflow facility when installed in conjunction with an existing cesspool; As a means of sewage disposal for limited, minor, or temporary uses.  Private Sewage Disposal Systems PRIVIES Outside Privy- oldest form of disposal of organic waste. Consists of a vault constructed of concrete for the collection of raw sewage and a wooden shelter  Private Sewage Disposal Systems COMMERCIAL / INDUSTRIAL SPECIAL LIQUID WASTE DISPOSAL REQUIREMENTS: When liquid wastes containing excessive amounts of grease, garbage, flammable wastes, sand, or other ingredients which may affect the operation of a private sewage disposal system, an interceptor for such waste shall be installed. DISPOSAL: Waste from interceptors may be discharged to a septic tank or other primary system or into a separate disposal system.  Private Sewage Disposal Systems GENERAL GUIDELINES FOR PRIVATE SEWAGE DISPOSAL SYSTEMS Location of Sewage Disposal System MIN. HORIZONTAL DISPOSAL SEEPAGE BLDG SEPTIC DISTANCE IN CLEAR FIELD PIT OR SEWER TANK REQUIRED FROM CESSPOOL 1 Buildings or 0.6 m 1.5 m 2.4 m 2.4 m structures* 2 Property line Clear** 1.5 m 1.5 m 2.4 m Adjoining private Property 3 Water supply 15.2 m 15.2 m 30.5 m 45.7 m wells 4 Streams 15.2 m 15.2 m 15.2 m 30.5 m 5 Trees - 3m - 3m  Private Sewage Disposal Systems GENERAL GUIDELINES FOR PRIVATE SEWAGE DISPOSAL SYSTEMS Location of Sewage Disposal System MIN. HORIZONTAL DISPOSAL SEEPAGE BLDG SEPTIC DISTANCE IN CLEAR FIELD PIT OR SEWER TANK REQUIRED FROM CESSPOOL 6 Seepage pits or - 1.5 m 1.5 m 3.7 m Cesspools 7 Disposal field 1.5 m 1.2 m 1.5 m 8 On site domestic 0.3 m 1.5 m 1.5 m 1.5 m Water service line 9 Pressure public 3m 3m 3m 3m Water main  Sewage Treatment Plan (STP) Some features of STP: An aeration system within the tank; A submersible mixer to mix the waste; A sludge waste pump that aids in clarifying; A decanter; Blowers; A fully electronic control system, etc.  Water Recycling 2 Most Common Types of Municipal Sewage Treatment The Activated Sludge Process Involves a series of stations where the raw sewage must pass through First Phase- gets rid of heavy materials with the use of three different filter houses Second Phase- clarifies the effluent Third Phase- hardens the sludge and converts it to fertilizers Produces water with 99-99.5% purity  Water Recycling Raw sewage inlet The Activated Sludge Process 1. Grit Chamber 2. Coarse screen house 4. incinerator 3. Fine screen house 5. Activated sludge tank 6. Aerating 8. Power House 7. Clarifier outlet basin 10. Liquid 11. Chemical 9. Drier house extractor house house 13. Vacuum 12. warehouse power house  Water Recycling The Trickling Filter Process a.k.a ‘Percolating or Sprinkling Filter System’ Requires less mechanical elements and less stages Produces water with 95% purity Requires a large ground area for its building STORM DRAINAGE SYSTEM  Rainwater Pipes DOWNSPOUTS OR CONDUCTOR PIPES, GUTTERS Rainwater piping shall not be used as soil, waste and vent pipes. Downspout and gutter sizes are based upon the maximum depth of rainfall per hour falling upon a given roof area in square meters. An ave. 102 mm/hr rainfall intensity is used around Metro Manila. Round, square (sized to enclose its equivalent round pipe) or rectangular (shall have at least the same cross-sectional area as its equivalent round pipe, except that the ratio of its side dimensions shall not exceed 3 to 1) rainwater pipes may be used for downspouts. Downspouts for high-rise buildings shall be of stronger pipe materials to resist the high hydrostatic pressure, they shall be installed within a pipe chase, and have no intermediate branch from the roof to the ground level.  Rainwater Pipes ROOF DRAINS Roof drains shall be equipped with dome-type strainers extending 102 mm above the surface of the roof surface. With a minimum total net inlet area of 1 – ½ times the area of the outlet pipe to which it is connected. Roof deck strainers shall be approved flat-surface type, with a total net inlet area not less than 2 times the area of the outlet pipe to which the drain is connected. Roof drains passing through building interiors shall be made watertight by the use of C.I. drain with integrally-cast waterstop ring around the outside of the body and placed at mid-depth of the concrete roof slab and the installation of a clamped suitable flashing material around the drain.  Storm Water System 3 Major Systems of Collecting Storm Water: The Independent System a.k.a. ‘the Separate System’ Brings collected water directly to the water reservoirs  Storm Water System The Combined System Combines storm water with sanitary wastes  Storm Water System The Natural System Without using any roof gutters or downspouts Also when rainwater is collected in cisterns Storm Drain Locations  Storm Water System Roofing Elements to Collect Rainwater: The Gutter Usually located along the entire perimeter of the roof The Downspout Located every 8 to 10 meters & at every corner of the roof (but, to avoid clogging of pipes, it is best to locate them every 4 to 6 m)  Storm Water System The Strainer or Roof Drain Drain designed to receive water collecting on the surface of a roof and to discharge it into a downspout. Designed to prevent clogging. The Shoe At the bottom of the roof leader to direct rain- water towards the nearest catch basin  Storm Water System The Catch Basin Downspouts should terminate in a catch basin (can serve more than one downspout) Delivers water to the sewers in the street via gravity Area-Drain-Catch-Basin: also collects surface water The Storm Line Connects to each catch basin  Storm Water System Storm Sewers Carries only rainwater collected from the storm drain or from the streets Terminates at natural drainage areas (i.e. lakes, rivers, and water reservoirs) Require manholes to serve as clean-outs and to make sewers accessible for inspection and repair built at depths of about 2 to 3 meters; diameter ranging from 0.6 to 1.2 meters THANK YOU !