What is Soak Pit | Estimate of Soak Pit | Design of Soak Pit

In this article, we will discuss about the, What is Soak Pit, Estimate of Soak Pit, Design of Soak Pit, Its Purpose, Function, Advantages and Disadvantages, Construction Procedure, Quantity etc 

What is Soak Pit?

A Soakage Pit is a covered, porous-walled chamber that allows water to slowly soak into the ground. The pre-settled sewage from the septic tank is released to the underground chamber, where it infiltrates into the neighboring soils. Estimate of Soak Pit

When wastewater is discharged into a soak-pit, it slowly soaks into the ground. The soak-pit is connected to a primary treatment unit and serves as a connection between the septic tank and the ground. Quantity of Soak Pit

Soak Pit Meaning:

A Soak pit or soakaway is a rectangular or circular underground porous chamber that allows wastewater from the septic tank to drain off slowly into the ground.

Function of Soak Pit:

When the greywater passes through the soak pit, smaller particles of effluents settle at the bottom of the soak pit. Microorganisms digest these smaller particles, and then filtered water is discharged out through porous walls. Quantity of Soak Pit

The following are some of the important functions of a soak pit;

1. The soak pit—which receives the effluent water from the primary treatment unit—serves to store wastewater and allow solids to settle before it is pumped back into the treatment unit. Quantity of Soak Pit
2. The secondary treatment unit partially treats the effluent water coming out of the primary treatment unit.
3. The treated water comes out of the porous walls of the soak pit because they are designed to do so. Quantity Function of Soak Pit
4. When it rains, the soak-pit fills with water that then seeps into the ground and recharges groundwater bodies.
5. The soak-pit acts as a filter, releasing only clear and non-harmful water into the ground. Quantity of Soak Pit

Soak Pit Design:

An open pit is dug in the ground and lined with porous material or left unlined and filled with gravel and coarse rocks. A stratum of sand and fine gravel is spread across the lowermost layer to aid in the dispersion of water. The pit is then covered on top.

Design Considerations of Soak Pit:

The following are some of the conditions that should be considered for the design of a soak pit.

1. In most cases, a soak pit should be a chamber of 1 m3 and the depth should be kept between 1.5 m and 4 m deep.
2. The bottom of the pit should always be at least 2 m above the groundwater table.
3. One option is to line it with a porous material, which can provide additional support and prevent the collapse of walls if it’s left empty. The other option is to leave it unlined and fill it with gravel or sand, which will still provide adequate space for wastewater.
4. In both cases, a layer of sand and fine gravel should be spread across the bottom of the soak pit to ensure that water flows evenly.
5. This pipeline should be built at a safe distance of at least 30 m from local water sources so as not to contaminate groundwater.
6. It should be ensured that the site does not collect rainwater, as too much mud filtered in the pit will clog the sand and gravel layer.
7. It’s a good idea to provide a concrete lid that can be removed easily when the pit needs to be maintained. Function of Soak Pit
8. It also should be away from high-traffic areas so that the soil above and around it is not compacted.

Soak Pit Construction Procedure / How to Build a Soakaway?

We will follow the following steps during the construction procedure of Soak Pit:

First, decide how big the pit should be based on how much space you have and how many people will be using it. Usually, a pit that’s (1 x 1 x 1.2) m3 is suitable for a family with 4- 5 members, which has the capacity to carry 300 per day.

Second, Excavate the pit of the required size. Manual excavation is preferred as it is less expensive than mechanical excavation. Function of Soak Pit

Third, If you use precast circular blocks, you can place them directly on the ground. If you want to use brick masonry, leave adequate gaps between the bricks.

Fourth, When connecting the effluent carrying pipe to the soak pit, be sure that the distance between the pipe and cover lid is minimal. Function of Soak Pit

Fifth, fill the pit with a variety of rocks, including brickbats and boulders.

At last, Cover the pit and make sure you can remove the cover for future maintenance.

How to Calculate the Estimate of Soak Pit:

In this estimate, we will find out the volume of the following items:

Earthwork Excavation

Brick Work in Cement Mortar 1:6 with Second class bricks

Dry Brick Work with Second Class Bricks

Brick Aggregates with 50mm size

Course Sand in Outer Side

Precast RCC Cover Slab

Placing of 100mm Dia vent pipe

Contingencies of Petty Item and Supervision charges

Bill of Quantity of Soakage Pit / Soak Pit Estimate Excel:

Free Download Excel File (Detailed Estimate)

Here is the detailed estimate (Excel File Free Download):

[su_button id=”download” url=”https://docs.google.com/spreadsheets/d/11zaDQhHfjINGBc4vT0Qy-_tjrGPeqtI0/edit?usp=sharing&ouid=108741018252176851323&rtpof=true&sd=true” target=”blank” size=”11″ wide=”yes” center=”yes”]Download[/su_button]

Advantages of Soak Pit:

Here are some advantages to consider if you’re planning to build a soak pit:

1. Soak pits can be built using materials found in the local environment.
2. It also helps recharge groundwater bodies, which are becoming increasingly important as a source of freshwater.
3. The installation of a soak pit requires a small space.
4. This technique can be used in rural areas, where water cannot always be directed away from a building, and in suburban areas where the drainage system is insufficient.
5. Construction can be very cost-effective and is available to almost anyone.
6. It is a technology that you can rely on, as it is sustainable.

Disadvantages of Soak Pit:

The following are some of the disadvantages of soak pit:

1. The primary treatment of wastewater is necessary to prevent the possibility of clogging, which is a health risk.
2. These technologies are not very effective and efficient at treating high volumes of effluents.
3. They are not a viable option in areas where the soil is not porous enough to allow the percolation of water.
4. If you build a soak pit at least 2 m below the groundwater table, then it should be suitable for disposing of your wastewater.
5. The installation of a waste disposal facility may have a negative impact on groundwater quality and soil properties if it is built too close to the groundwater table or if the effluent is highly toxic.
6. For people living in colder climates, this technology may not be suitable.
7. The highly congested area is not an appropriate place for this technology.

Operation and Maintenance of Soak Pit:

Most soak pits will last between three and five years if they are well maintained. To extend the life of a soak pit, make sure the effluent has been clarified and/or filtered to prevent solids from building up excessively.

Eventually, the soak pit will fill up with particles and biomass, and it will need to be cleaned or relocated. The material inside the soak pit can be excavated and refilled if necessary.

Health Aspects of Soak Pit:

Soak pits are generally constructed under the ground, and as a result, they are not likely to come into contact with humans or animals.

It can be adopted in even sensitive communities because it is odorless and has less contact with humans.

It is essential to locate a septic tank or soak pit at least 30 meters away from the drinking water source. Failure to do so can lead to contamination of the drinking water.

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