What Is a Plastic Septic Tank?

The three-format septic tank is composed of three interconnected sealed septic tanks, and the feces enter the first tank and then flow downstream to the third tank.

"Three formats" septic tank

The three-format septic tank is composed of three interconnected sealed septic tanks, and the feces enter the first tank and then flow downstream to the third tank.

Chinese name

"Three formats" septic tank

Make up

Three interconnected sealed septic tanks

Toilet House High

2.40 / m

Toilet area

1.20 / m2

1 Composition of harmless sanitary toilets

Under normal circumstances, toilets are composed of toilets, toilets and harmless treatment facilities.

Toilets: Basic requirements for toilets (for details, please refer to the "Sanitary Specifications for Rural Household Toilets" GB19379-2012)

Toilet: Toilet is a sanitary ware that must be used in the toilet. It is divided into two types: squatting toilet and toilet. Water flush toilets should use water-saving toilets. Indoor toilets must use water flush toilets.

Harmless treatment facilities: Harmless treatment facilities come in various forms, such as triple-format septic tanks, double-type septic tanks, and biogas digesters.

2 Basic requirements for sanitary household toilets

1 toilet house height / m 2.40

2 bathroom area / m2 1.20

3 Side window area / m2> 0.26

4 toilet door / m2 1.80 (height 2.0 x width 0.9)

5 Toilet roof cement board, machine tile, asbestos tile, etc.

6 Wall skirt for glazed porcelain or other impervious materials

7 Wall skirt height / m 1.00

8 The ground treatment floor is 100mm higher than the courtyard floor, and the material is non-slip floor tiles or cement.

9 Complete water supply and drainage facilities

10 The toilet meets the requirements of closed collection. The material is ceramic or good quality engineering plastic.

11 The septic tank meets the requirements for the harmless treatment of feces, and is sealed and leak-proof.

The items are mandatory, the rest are recommended values.

3 The composition of the three-cell septic tank: The three-format faecal treatment facilities are generally matched with water flush toilets.

4Three-cell septic tank: It consists of two cell-sealed septic tanks connected by two septic tubes. According to the main functions of the three tanks, they can be named as interception sedimentation and fermentation tank (first tank), re-fermentation tank (second tank) and manure storage tank (third tank).

5 Basic requirements for the volume of the three-cell septic tank (key)

The capacity of the three-cell septic tank should be determined according to the number of users, the flushing volume, the time for fermenting and septic fermentation, and the requirements for sterilization of sinking eggs. Manure fermentation and maturation time and pathogen death time are calculated according to 30 days, of which 20 days in the first pond, 10 days in the second pond, and the volume of the third pond is at least the sum of the two ponds.

1 Key points of construction method and construction technology

There are two main types of septic tank structures commonly used in our province, one is a brick structure and the other is a prefabricated reinforced concrete structure. Precast reinforced concrete structure septic tanks have been commercialized, as long as the site can be assembled as required. This section mainly introduces the construction and requirements of brick structured septic tanks. The key to the construction of Sange septic toilets is to ensure the quality of the building and prevent leakage; the second is to better control the quality of the septic pipe installation. (This tutorial uses the "2 cubic meter three-cell septic tank" recommended by the Jiangsu Province Office of Health and Welfare as an example)

2 Duties and obligations of construction personnel

Be responsible, be meticulous in work, and be responsible to users;

Study the construction drawings, master each link of the construction drawings, and propose an overall construction plan. Build or rebuild sanitary toilets according to the drawings to ensure the quality and build a qualified one;

Save raw materials and not cause waste;

Promote the benefits of sanitary toilets to users and the public;

3 site selection

For a family, the kitchen and toilet are indispensable parts and are closely related to people's lives. However, people only pay attention to diet and ignore another aspect of it-excretion. With the development of the rural economy, the problem of food and clothing for farmers has been solved, and living standards have continued to improve. Many farmers have built new houses and lived in new homes. But the toilets are very unhygienic, the location is not appropriate, and it is very unscientific. So, how to choose a toilet address?

For newly-built houses, or where tap water has been supplied indoors, overall consideration should be given to building toilets indoors, and arranging toilets, washrooms and bathrooms together to facilitate flushing.

Old-fashioned houses, or those without running water, it is best to build toilets in the yard. According to the prevailing wind direction in summer, the toilets should be built on the downwind side of the house. And feces removal is convenient.

If latrines are built outdoors due to housing conditions, they should be uniformly arranged according to the village construction plan. Choose a place with leeward sun, slightly higher terrain, solid soil, and low groundwater level, which is convenient for children and the elderly.

The three grid septic tank foundation should maintain a certain clear distance from the adjacent original building foundation, and its value is generally not less than the height difference of the bottom surface of the adjacent foundation.

4 Stakeout and digging

After selecting the location of the septic tank and determining the size of the septic tank, measure the size and sprinkle the lime line. Bricks should be left when laying out the wires, generally 150mm each. Then dig the pit according to the line. When excavating the pool pit, direct excavation should be adopted for the better soil quality, so that the bricks can be built close to the wall of the pit; for the poor soil quality or groundwater, the The slope is excavated on a slope, and the backfill width is not less than 150mm. During backfilling, 30% crushed stone or broken bricks can be mixed into the backfill soil. It must be symmetrical and uniform, and backfilled and compacted while masonry, which can act as a bucket hoop on the wall of the pool. For areas with high groundwater levels, before excavating a pool pit, a 2-meter-deep water collection well must be dug near the pool location and pumped water in the well. Only in this way can the excavation of the pool pit and the completion of the task of the pool be constructed under the condition of continuous drainage of groundwater.

5 Pool floor

Surface layer: mortar surface, thickness 20mm (constructed with the wall at the same time)

Upper layer: cast with C15 or C20 concrete, thickness 80mm

Middle layer: tamped with crushed stone or broken brick cushion thickness 100mm

The lowest layer: plain soil compaction

6 Septic tank body

Brickwork: Use MU7.5 (75) clay brick and M7.5 (75) mixed mortar for masonry; the shape and size of the brick (mm), or 240 × 115 × 53 Bricks, or eight or five bricks of 216 × 105 × 43 can be used.

Brick septic tank: According to the size of the septic tank, build the wall first, divide it into three grids, and separate the two walls in the middle. Due to the narrowness of the second pond, the construction is difficult. Good cement before continuing to build walls (preferably not to do this).

Pay attention to mastering the installation time, position and direction of the inlet pipe, through pipe, and outlet pipe.

Pool wall plastering: the outer wall of the pool is bottomed with 1: 3 cement mortar, 1: 2 cement mortar plastered surface, 20 mm thick, plastering starts from the top of the pool and 200 mm below the ground surface; all plastering of the inner wall of the pool must be plastered It is important because it is an important measure to prevent septic tank leakage. The inner wall plastering should adopt three-layer method, 1: 2.5 waterproof mortar, 20mm thick. The surface must be dense and smooth;

7 pool roof and pool cover

An important principle of the three-format septic tank for manure treatment is closed anaerobic. This effect mainly depends on the effect of the tank cover. Therefore, the size, shape, thickness and connection to the tank of the tank have strict requirements.

The size of the pool cover should match the size of the pool body. The thickness depends on the ground position of the septic tank, which is 4-8cm, usually 5cm. The outer edge of the pool cover can be designed as an inner groove edge. Whether a small lid should be added to the large lid of each pond should be designed according to the living habits and dung habits of local farmers.

The pool roof (big cover) can be made of C18 (No. 200) reinforced concrete, No. 3 steel (grade ) steel prefabricated, and the protective layer is 15mm thick. The cover thickness is 5cm. The pool cover (small cover) is a prefabricated concrete member, square cover or round cover, preferably a round platform type. It adopts C18 (200) concrete and 3 steel (grade ) reinforced protective layer thickness 15mm. The tightness of the joint with the top plate shall not exceed the error of the pouring dimension by more than ± 5mm.

When installing the large cover plate, the top surface around the tank should be sealed with "bottom mortar" and placed flat and stable. However, it should not be sealed with cement. The mouth cover (small cover) should be tightly closed to prevent rainwater from flowing and ensure the seal fermentation in the tank.

8 Toilet: The toilet can be a toilet or a squat toilet. The indoor toilet must use a water flush toilet and has a water seal function.

9 Manure inlet pipe: It is suitable to use a pipa bend with an inner diameter of 150mm and a wall thickness of 6mm. It is connected to a 5% sloping manure pipe and connected to a septic tank. The lower end of the inlet pipe sinks into the surface of the faecal fluid, and its depth is about 1/2 of the height of the faecal fluid surface, that is, 500 mm from the bottom of the pond. The upper end of the inlet pipe should be higher than the outlet of the stool (picture).

10 Fecal tube: The commonly used connecting tube is a curved or oblique cannula with a diameter of 100 mm. The height of the lower end of the connecting pipe from the bottom of the pool should be about 1/3 of the height of the liquid surface of the pool, that is, 350mm. This is because this height is in the middle of the liquid layer between the dung skin and the dung. The upper end of the communication pipe is the outlet of the dung water. In order to control the level of the dung liquid level in the first tank, it is generally 1 away from the bottom of the tank. Meters, 20cm from the top of the pool.

11 Ground treatment: The septic tank should be 5-10cm higher than the surrounding ground to prevent rainwater from flowing in. The loose soil around the pool should be compacted, and the floor in the toilet should be bottomed with 1: 3 cement mortar, and then the surface should be wiped with 1: 2 cement mortar. Conditional farmers can stick tiles, which is more conducive to cleaning and keeping clean.

12 Test the water

Leakage is the most prone problem for sange septic tanks, because septic tanks are underground and soaked by groundwater, and the feces are also corrosive. Leakage not only directly affects the use of toilets, but also easily causes pollution to surrounding soil. . The requirements for building materials such as brick and cement quality and mortar ratio are high, and the construction technology should be strictly controlled.

After the septic tank is built, the water should be tested first to see if there is a leak in the tank. If there is a leak, it must be repaired to prevent leakage. Leakage inspection method. Fill each tank with water. If the water level drops within 1cm within 24 hours, there is no leakage. If the water level drops below 1cm, there is leakage. Use cement slurry containing anti-seepage powder to wipe the surface 1-2 times. If the liquid level rises, it indicates that the groundwater level is high and there is groundwater infiltration, and corresponding measures should be taken to prevent seepage and floating.

13 Preparation for use: Before using the sanitary toilet, the first pond must be flooded with river pond or well water until it passes through the lower mouth of the manure pipe to make the manure easy to ferment after entering the pool. Do not add water to the second and third pools.

14. Purification treatment of fecal fluid at the outlet of the third tank

The ideal way for the third tank of the sange septic tank is to use fertilizer for farmland fertilization. However, farmers in some areas have replaced manure with chemical fertilizer and the amount of manure water has been reduced. Therefore, it is necessary to find a suitable purification treatment method for excess manure water. Four-format ecological toilets have been tried out in some areas, and shallow soil purification ditch or purification pit technology is also a relatively simple and effective treatment method.

4. Management requirements for use of sanitary toilets

Use and management of septic tanks

Keep the sanitary environment in the toilets. Household toilets should be cleaned frequently, and the ground, walls, roofs, doors and windows should be kept clean.

Rinse after going to the toilet. Water flush toilets with tap water should be diverted into the toilets. Dry toilets without tap water should be provided with a container to hold water for flushing. There should be no faeces and urine in the toilet, so that the toilet should be free of odor and fly.

Pay attention to the correct use of water in the toilet. Do not pour domestic sewage into the toilet, or discharge domestic sewage into the septic tank, so that the sewage and domestic sewage are separated and discharged.

The amount of flushing after the stool should be as small as possible, which can save water without flushing the concentration of manure too much. To this end, the use of water-saving toilets is recommended.

Proper use of septic tanks

Before the new septic tank is used, a certain amount of water should be added in the first tank (or the front pond, ) in advance, and the water surface exceeds the opening at the lower end of the communication to form a water seal to prevent the communication pipe from being blocked by the faeceskin, or Allow a large amount of fecal fluid to float into the second tank (or back pond, hoe). Manure is not allowed to be taken as fertilizer in the first pond (or front pond, hoe), and only manure is to be taken for fertilization in the third pond (or back pond, hoe), because the former does not meet the requirements for harmless manure. Can cause the occurrence or epidemic of intestinal infectious diseases and parasitic diseases, and the latter generally meet the standard of fecal harmlessness, safe after fertilization.

The large cover plate on the top of the septic tank can only be opened when the dung or dung water is removed, and it must be covered normally. If it is used more frequently, in order to prevent the mosquito and flies from breeding, you can usually spray some disinfectant solution to ensure safety and hygiene.

Clean up excreta in time

According to the use situation, the dung skin and dregs should be removed in a timely manner and cleaned once every six months to one year to avoid reducing the effective volume of the septic tank and affecting its harmless sanitary treatment effect. The excreted dung skin and dregs should be sterilized.

Appendix A Atlas of Harmless Sanitary Household Toilets-Sange Septic Tank

2 cubic three grid septic tank floor plan

Sectional view of 2 cubic three grid septic tank

2 cubic three grid septic tank plan 2