G. S. Dikondawar GM – Innovation & TechnologyThe Supreme Industries Ltd.

• Introduction• Disadvantages of conventional products• Septic system• Existing system• Problems associated with existing system• Changing factors demanding new solution• Safegard septic tank

a) Vertical design

b) Modular design• Components of septic tank• Product range• Features and benefits• Installation procedures • Guidelines for abnormal conditions• Standards and Test requirements• Design consideration of Safegard septic tank• Requirement of BIS• Capacity calculation

Contents

An Introduction Sanitation has direct link with the health and the environment People suffer serious health consequences and millions of people die as a

result of lack of effective sanitation Use of inefficient drainage systems and sewer products are the main

reasons. Advance products/sewerage system has the potential to change the

scenario. Developed countries have switched over to advance products. Plastic Drainage/ Sewer Pipe systems minimize Sanitation risks and improve

health and environmental aspects.

Future India….Three aspects of our current budget focus on:- Total Sanitation is expected to be achieved through Swatchh Bharat

Abhiyan by 2019 at a cost of 1000 Cr Rupees.

- Allocation of 7060 Cr for the development of 100 Smart Cities which will include Road, Electricity, Water supply and Sanitation.

- All Schools to have Toilet facility

Disadvantages of conventional drainage products1. Heavy weight – 12 times the weight of plastics. Need of heavy equipments,

more manpower- more installed cost

2. Cumbersome and time consuming installation

3. Poor resistance to Corrosion

4. Rough internal surface leads to blocks, solid depositions, encrustation and consequent reduction in internal dia and flow

5. Rough bore also leads to more friction, lesser flow or needs higher slope (means more earthwork, costs)

6. Poor resistance to soil movement due to lack of flexibility

7. Cracks and leaks lead to root penetration into the pipe system

8. Repeated maintenance requirement - High maintenance cost

9. Unhygienic and Unsafe – Non eco-friendly

10. Lower life expectancy ( 15 -20 years) resulting in higher life time costs

Septic System

Septic TankDrain field /Soak PitSeptic system

• Definition

A septic system is a highly efficient, self-contained, underground wastewater treatment system. As septic systems treat and dispose of household wastewater onsite, they are often more economical than centralized sewer systems in rural areas where plot sizes are larger and houses are spaced widely apart. And by using natural processes to treat the wastewater onsite, usually in a homeowner's backyard, septic systems don't require the installation of miles of sewer lines, making them less disruptive to the environment.

• Features - Natural waste water treatment - Simple design- Less expensive - Easy for installation & maintenance

Septic system

The septic tank is basically a watertight underground tank, the purpose of which is the collection, storage, and to some extent treatment of sewage/effluents. Septic tanks are usually made of concrete or masonry, with an inlet and outlet pipe. Wastewater flows from the home to the septic tank through the sewer pipe. The septic tank treats the wastewater naturally by holding it in the tank long enough for solids and liquids to separate. The wastewater forms three layers inside the tank. Solids lighter than water (such as greases and oils) float to the top forming a layer of scum. Solids heavier than water settle at the bottom of the tank forming a layer of sludge. This leaves a middle layer of partially clarified wastewater.

Septic Tank

- Collection of waste water

- Retention / holding

- Sedimentation / settlement

- Anaerobic digestion

- Flocculation

- Clarification

- Discharge

Working of Septic Tank

Typical layout of septic system

• Effluent - The supernatant liquid discharge from a septic tank.

• Invert - The lowest point of the interior of a sewer or drain at any cross-section.

• Scum - The greasy and other substances floating on the surface of sewage.

• Septic Tank - A water-tight single storied tank in which sewage is retained sufficiently long to permit sedimentation.

• Sewage - The liquid waste of a household or community including human excreta.

• Sludge - Sludge is the settled solid matter in semi-solid condition.

Terminology

Function of septic tank

a) Drain field

The drain field is a network of perforated pipes (or "laterals"). These are laid in gravel-filled trenches or beds. After solids settle in the septic tank, the liquid wastewater or effluent is discharged. This is done either by gravity or pressure, to an absorption field, also known as a drain field or leach field.

b) Soak Pit

The effluent discharge from the septic tank may contain disease causing germs and pollutants which must be treated to protect human health and environment. Hence these effluents should be carefully and safely disposed either in the drain field or soak pit to facilitate disintegration through bacterial action.

Disposal of septic tank effluents

Inner perforated pipe

External perforated pipe

Septic tankInlet pipe

Outlet pipe

Distribution box

Gravel filled trench

Typical diagram showing drain field

Video for drain field

A soak pit is a covered, porous-walled chamber that allows water to slowly soak into the ground. Effluent from septic tank is discharged to the underground chamber from where it infiltrates into the surrounding soil.

Soak Pit

Brick masonry

Conventional septic tank

RCC / Hume pipe

Existing system

• Leakages • Infiltration • Ex-filtration • Root penetration • Breakages - Insufficient resistance to earth, traffic loads• Corrosion • Insufficient resistance to acids & chemicals• Rough interior surface - deposition & incrustation• Laborious and time consuming installation • Frequent maintenance requirements

Diff. problems in conventional septic tanks

• Excess load on septic tank• Improper digestion (decomposition) of solid wastes• Pollution of underground water • Contamination of soil • Unhygienic & harmful for environment • Water born disease & serious health problems• Uncertain & short life span• Fatal accidents • Dryness of septic tank

Consequences

• Standard of living/Health consciousness

• Nature of sewage

• Space constraints

• Time constraints

• To overcome problems with existing system

Factors demanding advance solution

1. Sufficient area for sludge digestion 2. Holding capacity of waste water (minimum 24 hrs.)3. Water tight structure 4. Sufficient volume to collect retain & digest solid waste 5. Long cleaning period 6. Easy for maintenance 7. Easy for transportation, handling & installation 8. Excellent performance 9. Better effluent quality (exceeds the standard parameters)10. Sufficiently strong to sustain different loading condition

Design consideration of Safegard septic tank

The surface area of the tank required should be O-92 m² for every 10 liters per minute of peak flow rate at a temperature of 25°.

A minimum depth of sedimentation shall be 250 to 300 mm.

Sludge digestion per capita suspended solids entering the tank may be taken as 70 g/day.

The capacity required for sludge digestion is 0.033 m³ per capita at 25°C.

Volume of digested sludge is normally O-000 21 m³ per capita per day.

Detention Time provides a detention period of 24 to 48 hours based on an average daily flow of sewage.

Requirement of BIS

Unique Design – Rototationally moulded, one piece seamless construction with two chamber patented design

Great Strength - Highly durable Light in weight - Simple and quick Installation Excellent Chemical Resistance - free from concrete corrosion and ill

effects of H2S Minimum space and excavation requirements Free from infiltration, ex-filtration and root penetration Long life with economy Hygienic and safe Eco-friendly Conforms to National and International standards Maintenance free

Safegard septic tanks - Unique features

• Available in 1000, 1500, 2000, 3000, 5500 liters and large size up to 29500 liters in modular design.

• EN 12566, IS:2470

Available sizes and applicable standards

Vertical design Modular design

Diff. designs of Safegard septic tanks

Components of vertical septic tanks

Typical section of vertical septic tank

Functioning of septic tank

1) EXCAVATIONExcavate a pit approximately 600 mm larger than the size of septic tank. Depth of the pit should be decided based on position of inlet and outlet with required gradient and disposal point plus 150 mm extra for bedding.

2) BED PREPARATIONEnsure that the base of the pit is even, flat and sufficiently hard to form a strong foundation for the septic tank. Prepare a 150 mm (6”) thick bed of granular material and compact it properly. Ensure that no sharp object/stone etc should protrude which can puncture the tank.

Installation of septic tank

3) POSITIONING THE TANKLower the tank and position in the pit ensuring that it is vertical, centrally positioned, correctly aligned and leveled using spirit level and the outlet pipe faces the soak pit and inlet pipe swivels, ensuring a straight connection.

4) FILL THE WATER IN THE TANKFill up the tank with water up to 1/3rd capacity using tap.

5) BACKFILLINGStart the backfilling. Backfilling and water filling should be carried out simultaneously ensuring that the backfilling level never exceeds the rising level of water within the tank until the water overflows through the outlet pipe, thus indicating the tank is full. The width of the backfilling should be minimum 300 mm (12”) around the tank. Excavated soil can be used if it is silt, sand or soft murum but in case of black cotton, loomy or marshy soil only selected inert granular material i.e. sand /stone dust /gravels (max. size 10 mm) should be used as backfill material. Backfill material should be placed in 250 mm thick layers and compacted to 90% proctor density. It is particularly important to note that excavated material consisting of rock, peat or clay is not used as backfill material.

6) MAKE THE PIPE CONNECTIONSWhen the level of the backfill reaches the underside of the outlet pipe invert, inlet and outlet connections should be made. It is recommended to maintain 1:40 to 1:60 fall between drain head and inlet of the septic tank.

7) FINAL BACKFILLINGAfter making pipe connections, complete the backfilling up to the top level of the tank. In case of non traffic conditions, normal flooring like PCC / paver blocks etc. can meet the requirements.

8) PROVIDING COVER / LIDSelect the appropriate cover as per the site loading conditions and place it on the top of tank. In case of pedestrian movement where vehicular loads are not expected, plastic light weight cover is recommended. This plastic cover should filled with concrete after placing it on the septic tank. For vehicular traffic movement GRP cover of appropriate load class is recommended. For GRP covers 150 mm thick PCC (min. M150 grade) beneath the cover frame for full width of tank is recommended. After embedding the frame, place the cover as shown in the figures.

Components of modular septic tanks

Components of modular septic tanks

Typical diagram of modular tanks fordifferent capacities

Installation of modular tanks

1) Excavation of the pitExcavate a pit approximately 600 mm larger than the size of septic tank. Depth of the pit should be decided based on the position of inlet and outlet with required gradient and disposal point plus 150 mm extra for bedding.

2) Bed preparationPrepare a 150 mm (6”) thick bed of granular material and compact it properly. Ensure that the base of the pit is smooth and flat. It should be sufficiently hard to form a strong foundation for the septic tank. There should not be any sharp objects/stones etc. which could protrude and puncture the tank. In case of soft strata or loose soil like black cotton, marshy or loamy soil, it is recommended to provide a flat cast in-situ 150 mm thick concrete slab.

3) Positioning the first componentLower and position the first modular tank component in the pit. Ensure that it is vertical and centrally positioned. Align it correctly and level using spirit level. While positioning ensure that outlet side (having dome end) faces the soak pit or drain field.Cut the hole(s) at provided slot(s) to fit inter connecting pipes as per the requirement and set guidelines given in the following chart. Fix the rubber seals on the holes. Backfill carefully with recommended backfilling material. Ensure that no voids remain especially under and between the legs of the tank to a depth of 400 mm above the bed or cast in situ concrete slab.

4) Intermediate pipe connectionsApply rubber lubricant on the rubber seal(s) provided on the holes cut on the flat portion and insert inter connecting pipes as per the requirements / set guidelines.

5) Push the pipesPush the inter connecting pipes fully inside the first component.

6) Positioning the second componentLower the second component and align it properly. Cut the slots and place the rubber seal on this second component for connecting it with the first component using connecting pipes. Bring it close to the already positioned first component and match the slots.

7) Alignment of two componentsAlign the holes of two adjoining components, push and insert the connecting pipes from inside the first component as shown in the above figure. Repeat the backfilling as shown in step 3.

8) Positioning the last componentPlace the last component in the pit and repeat the same procedure for connecting it with the adjoining middle component.Procedure explained herewith should be repeated for additional intermediate components for increased capacity.

9) Fixing and alignment of last componentAlign the last component and match with the earlier installed middle component and connect each other using connecting pipes as per the earlier explained procedure.

10) Fill the tank with waterFill up the tank with water up to 1/3rd capacity using tap before backfilling.

The width of the backfilling should be minimum 300 mm (12”) around the tank. Excavated soil can be used if it is silt, sand or soft murum but in case of black cotton, loomy or marshy soils only selected inert granular material i.e. sand /stone dust /gravels (max. size 10mm) should be used as backfill material. Backfill material should be placed in 250 mm thick layers and compacted to 90% proctor density. It is particularly important to note that excavated material consisting of rock, peat or clay is not used as backfill material. Note - for installation in water logged areas or where the water table is shallower, it is recommended to refer the installation procedure for abnormal condition.

11) Backfilling and compactionStart the backfilling. Backfilling and water filling should be carried out simultaneously ensuring that the backfilling level never exceeds the rising level of water within the tank until the water overflows through the outlet pipe thus indicating the tank is full.

12) Make the inlet and outlet connectionsMake the connections of inlet and outlet including hopper.

13) Cast the concrete slab (Optional) and place the coverComplete the backfilling above outlet pipe. Select the appropriate cover solution as per the site loading conditions and place it on the top of tank. In case of pedestrian movement where vehicular loads are not expected, plastic light weight cover is recommended. This plastic cover should filled with concrete after placing it on the septic tank. For vehicular traffic movement GRP cover of appropriate load class is recommended. For GRP covers 150 mm thick PCC (min. M150 grade) beneath the cover frame for full width of tank is recommended. After embedding the frame, place the cover as shown in the figures.Note : If required height of the manhole can be raised using height riser(s).

Cover Solutions for modular septic tanksTypical diagrams should be referred for installation of appropriate covers.

Installation procedure

Installation procedure

Guidelines for abnormal conditions• In case of marshy/black cotton and loose soil, or where the water table is a problem,

excavated soil is not recommended for backfilling, a cement-stabilized backfill mix of 5% cement and 95% inert granular material must be compacted in 250 mm layers to 90% proctor density and 6" thick R.C.C. with nominal steel enforcement is recommended at the top.

• In case of soft murrum, it can be used as backfilling material with proper compaction (90 % of proctor density), in 150 mm layers.

• Care should be taken to avoid direct contact of sharp edges, objects with the tank.• In case of high water table areas, septic tanks should be anchored in concrete as per the

guidelines of engineer in charge. • Safegard Septic Tanks are not designed to be buried more than 0.5 m below ground level. If

depths are greater than 0.5 m, please refer to site engineer/architect.• If the abnormal soil conditions occur like vehicular traffic, rocks, black cotton soil, or when

the high water table is anticipated or when the backfill above the lid may exceeds 0.5 m, then the final design rests with the engineer or architect on the project. However guidelines given herewith must be strictly followed for best satisfactory performance.

Manufacturing – as per EN 12566

Manufacturing standards and test requirements of septic tanksTest Requirements

Sr. No. Test Requirement1 Dimensions Inlets, outlets, and connections Accessibility2 Load bearing capacity

a. Backfill load For vertical - hx18 kN/m² h= height, specific weight of soil 18 kN/m3 b. Hydrostatic load For vertical - Hw x 10 kN/m² specific load of soil / specific mass of water 10

kN/m3 c. Dynamic load i) Pedestrian Load For less than 1m = 2.5kN/m² ii) Vehicle Load

3 Water tightness a. Water test No leakageb. Air permeability vacuum test

0.1 bar for 60 sec, 0.2 bar for 30 sec, 0.3 bar for 15 sec

c. Pneumatic pressure test 0.3 bar for 3 min

4 Volume / Nominal Capacity test

Septic tank capacity recorded in liters

5 Structural behaviour a. Dry conditions Vertical load test - hx18 KN/m² h= height, specific weight of soil 18 KN/m3

Determination of mechanical characteristics of test samples used for calculations (flexural modulus)Pit Test Determination of mechanical characteristics of test samples used for calculations (flexural modulus)Pit Test

Volume of tank = Volume for sludge + Volume for retained water + freeboard

For example, a) Volume of sludge / person / year = 27 liters.b) Water supply / person / day = 80 liters.c) Average population of a household = 5 nos.d) Cleaning period = 5 years.e) Volume required for sludge = (a x c x d) = (27x5x5) = 675 liters a) Volume of water retained in the tank in 24 h = ((b x 0.8) x 5) = ((80 x 0.8) x 5) = 320 liters. = (e + f) = 675 + 320 = 995 liters say 1000 liters.Summary – for 80 lpcd, 5 people & 5 years use 1000 liters septic tank is required. In addition to 1000 liters capacity a freeboard of 250 mm is required.

Capacity calculations

Comparison with Hume pipe construction

Comparison with Safegard septic tank Manufactures claim• Total capacity - 2800 ltrs.• Capacity up to liquid level - 2490 ltrs.• Recommended no of users – 50Suitable for• Sludge volume per users / year - 27 ltrs.• Sludge volume for 50 users / year - 1350 ltrs.• Volume for waste water to be retained - 4800 ltrs.• Free board required - 310 ltrs. min.• Total volume for 50 Users for one year - 6460 ltrs.• Available capacity is - 2800 ltrs. Summary• Thus this tanks is suitable only for 20 users for one year it means Safegard 3000 liters tank is suitable.• Cost of this tank is Rs.18000 against Rs. 36000/-

Life cycle cost analysis

Description RCC Septic Tank Safegard Septic Tank

LifeProduct Cost

Maintenance Cost

Total Cost with

Conventional Product

15 - 20 Years

Rs.18,000/-

Rs.12,000/- (20 Yrs.) @ Rs.600/year

18,000 + 12,000 = Rs.30,000/-

30,000/20 = 1,500 Rs./Year

80 Years

Rs.36,000/-

Rs.32,000/- (80 Yrs.) @ Rs.400/year

36,000 + 32,000 = Rs.68,000/-

68,000/80 = 850 Rs./Year

Comparison Summary

Sr. No.

RCC Hume pipe Suggested size of Safegard in L

Cleaning time

(1 year)

Cost Life cycle cost per yearTank

size in L

Recommended for no of user / tank

Actually suitable for 1 year RCC Safegard RCC Safegard

1 1600 25 12 users 1500 9000 18000 650 2252 2800 50 22 users 3000 18000 36000 1194 4503 6300 100 48 users 5500 35000 66000 2155 825

Advantages of Vertical v/s Horizontal design Minimum space requirement Minimum external loads Better settlement and decomposition of soil waste Better quality of effluent discharge Economical design

Different Tests on Septic tanks Material properties Vacuum test Structural behavior - Collapse

load Dynamic load test Water tightness test Pneumatic pressure test Hydraulic efficiency test

Water storage solution . . . Total water storage solution provider

• SILTANK overhead water storage and loft tanks in different capacities from 100 to 5000 liters

• Amrutam underground water storage tanks in different capacities from 1000 to 30000 liters

Overhead Water Tanks… Strong, Sturdy and Long Lasting tanks

Unique features of Overhead water tank 100% virgin raw material Strong and Durable Thermal Insulation with foam layer (four layered) Excellent chemical resistance Meets and exceed all quality parameters as specified in IS standard BIS marked two layer tanks are also available UV Stability Full capacity guaranteed Most suitable for drinking water Easy and quick installation Available in 500, 750, 1000, 1500, 2000, 3000 and 5000 liters Two cover options – one with simple rotate and lock type and other with

threaded type covers

Overhead water tank sizes with dimensions

CAPACITY Available Layers Diameter Height Manhole ID500 liters 2/3/4 868 1060 390750 liters 2/3/4 1000 1168 3901000 liters 2/3/4 1071 1325 3901500 Liters 2/3/4 1267 1454 3902000 Liters 2/3/4 1434 1503 4603000 Liters 2/3 1611 1733 4605000 Liters 2/3 1936 2047 460All dimensions are in mm

Loft Tanks… Strong, Sturdy and Long Lasting tanks

100% virgin raw material Food grade material Strong and Durable Full capacity guaranteed Most suitable for drinking water Net storage capacity exceeds the mentioned capacity Easy and quick installation Available in 100, 150, 200, 300, 400 and 500 liters

Unique features of loft tanks

CAPACITY Length Width Height Manhole ID100 liters 585 585 373.0 300150 liters 715 715 371.0 300200 liters 900 500 475.0 300• Liters 965 705 385.0 300300 Liters 1205 825 378 300400 Liters (Option 1) 1195 920 450 300400 Liters (Option 2) 1290 1004 390 300500 Liters (Option 1)* 1415 870 490 300500 Liters (Option 2)* 1505 996 408 300* Two openings with lid , all dimensions are in mm

Dimensional details of loft tanks

Underground Water Tanks

Available in 1000, 1500, 2000,3000 liters in vertical design and 6000 and bigger capacities up to 30000 liters in modular design

Unique features of Amrutam underground water tank

Rotational moulded single piece construction up to 3000 liters Great strength – Robustly designed with unique rib structure Simple and quick installation 100% water tight – free from root penetration Provided with air tight threaded cover Hygienic and safe – free from corrosion and biological growth Minimum maintenance requirements 100% virgin raw material Full capacity guaranteed Long life – minimum 50 years of service life Available in 1000 to 30000 liters capacity in vertical and modular design

Amrutam vertical tank sizes with dimensions

CAPACITY Diameter Height Manhole ID1000 Liters 1200 1321 3901500 Liters 1200 1692 3901800 Liters 1200 2052 3902000 Liters 1700 1301 3903000 Liters 1700 1748 390All dimensions are in mm

Amrutam modular tank sizes with dimensions

CAPACITY Diameter Length6000 Liters 2200 240010000 Liters 2200 380014000 Liters 2200 520018000 Liters 2200 660022000 Liters 2200 800026000 Liters 2200 940030000 Liters 2200 10800All dimensions are in mm

Thank you…