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Long gone are the days when in a private house everyone was satisfied with a “birdhouse” on the street. The modern standard of comfortable life, even in the country, requires the presence of a normal toilet and, at least, a shower. And in the house there is often more than one bathroom, and in addition a lot of household appliances. To ensure the required level of comfort, sewerage for a private house must be done correctly and its basis is the choice of a method for processing wastewater.
Septic tank and local treatment plant – what’s the difference
Today, there are three ways to make an autonomous sewer for a private house:
- Drains come to the storage tank, from where they are periodically pumped out by a sewage machine. The simplest option that does not involve any processing and purification. Storage tank – a sewage pit (necessarily sealed) or a plastic container.
How sewerage works for a private house with storage capacity - Drains are cleaned in a septic tank – containers made of plastic or concrete (plastered brick). The process occurs due to the “work” of anaerobic bacteria that enter the septic tank with waste. Purification after septic tanks is not complete (60-70%), the water needs additional purification, although after a good septic tank it looks transparent and often there is even no smell. However, such water cannot even be used as technical water – it does not meet the standards. For complete cleaning (up to 90-95%), one of the filtering devices (well, ditch, filtration field) is usually installed after the septic tank. After such purification, the water usually meets the technical criteria.
Septic tank needs to be treated - Complete wastewater treatment takes place in local treatment plants (VOCs for short). In them, purification occurs due to the vital activity of aerobic bacteria (they live in the presence of air), therefore constant aeration is necessary for work. Pumps work constantly, because such a sewer for a private house is also called an aeration unit (AU). At the outlet of the AC, wastewater can immediately be used as process water. True, it meets these criteria only after the installation enters the operating mode (when the colony of bacteria multiplies in sufficient numbers). This may take up to 2-3 weeks.
Water after VOC can be discharged into the gutter
Out of ignorance, many call both those and other installations septic tanks, although these are different solutions that have drains that are cleaned to different degrees at the outlet. And although Topas, Poplar, Unilos, Tver are also called septic tanks, they are autonomous cleaning plants. Actually traditional septic tanks are Tank, Termite, Rostock, Mole, and many others.
Autonomous stations for the processing of wastewater (autonomous sewage) are often called a toilet for a house without pumping. This means that there is no need to call a sewage truck, but you still need to pump out the sludge. It’s just that the amount of sludge is about 10 buckets, you can remove it yourself using the built-in or fecal pump.
To understand which of the solution methods – AC or septic tank – is better, you must first understand how they differ, and then consider the specific situation. Sewerage for a private house can be done correctly without the involvement of specialists – with your own hands, but for this you need to clearly understand what and why you need to do. Let’s figure it out.
Features of septic tanks
Septic tanks are several reservoirs-chambers interconnected by overflow pipes. Each of the chambers has its own cleaning stage. Its basis is fermentation and decomposition by anaerobic bacteria (they can live without oxygen), which are contained in waste. The more chambers in the septic tank, the more purification steps, the cleaner the output water is. But more than 50-60% without additional filtration measures can be obtained very rarely.
Septic tanks are made of plastic, fiberglass, concrete, very rarely – stainless steel. The cameras can be implemented in one housing, or they can be separate. To save money, they often build septic tanks with their own hands. Most often, a septic tank is made of concrete rings, but they are also built of brick or reinforced concrete. Please note that the container must be absolutely sealed. This is very important when building your own.
Basic properties
We will deal with the features of the work of septic tanks. They are:
- At the exit from the septic tank, the drains are cleaned by 50-75%. Without additional cleaning, they cannot be thrown onto the terrain, into water bodies or used for technical needs (lawn watering, car washing, etc.). Therefore, from the outlet of the septic tank, effluents are fed to filtration fields / ditches, to filtration wells.
- In addition to the presence of drains, a septic tank does not require anything to work. It is energy-independent, they do not need to be populated with bacteria. They are contained in sufficient quantities in the waste that enters the tank. In the septic tank, they still actively multiply, since the optimal environment has been created for them here.
One of the septic options - Bacteria living in a septic tank do not need daily feeding. This is an ideal option for temporary residence – for summer cottages or country houses with a “ragged” mode of activity. They will safely continue their life activity “without feeding” for a long time.
- With the correct calculation of the volume, the septic tank is not afraid of the increased salvo discharge of wastewater. That is, when flushing the water and the bathroom, you can not worry and flush the toilet, use taps, etc.
- The presence of a large number of disinfectants and detergents is not very good for bacteria. Since the volume of the chambers is large, it is difficult for them to cause tangible harm. When such active chemistry is dumped, some of the bacteria will die, but most will remain. So one-time powerful receipts of chemistry will not affect the quality of cleaning.
Internal structure
The main disadvantage of this method of cleaning wastewater from a private house is the need for post-treatment. More funds are needed for the installation of additional structures, but without them, the sewerage system for a private house will not be correct. It is impossible to dump semi-treated effluents on the ground. They will very quickly fall into the water and return to your and neighboring wells and wells. This will not bring you joy and health, and you also need to endure the “gratitude” of your neighbors. So let’s figure out how to clean the drains after a septic tank.
Where to put drains
Please note that paired with a septic tank, you must have an after-treatment device. Depending on the soil, this can be a filtration well, a filtration ditch or a field (underground or bulk). Only in this case can cleaning be considered complete. Which type of filter elements to make depends on the type of soil and the level of groundwater. Read about the selection method and the septic tanks themselves here.
Local treatment plants (VOC or AC)
Autonomous sewerage installations, during normal operation, are capable of obtaining fairly clean water. It cannot be used as drinking water or for watering the garden, but as a technical one it is very possible. The basis of purification is the work of aerobic bacteria (they live in the presence of oxygen). The waste processed by them turns into sludge, settles to the bottom of a special tank, from where it is then pumped out. The pumping frequency is 1-4 times a year, depending on the intensity of use.
In general, an autonomous wastewater treatment plant is a good thing, but it has certain operating features that you must know before deciding which is better for sewerage of a private house – a septic tank or an AC.
At the outlet, ACs have water purified by 90-95%. With this quality, it can be poured onto the ground, however, for this you must have laboratory tests on hand. Therefore, many still prefer to use an intermediate settling well from which water is then used for technical purposes. The second option is to divert wastewater to filtering devices. This, of course, reinsurance, but in emergency situations it saves.
What cleans up waste
Waste is processed by anaerobic bacteria (live only in the presence of air). Aerators are constantly working to provide them with air in the VOC. In addition, during cleaning, the transfer of contents from one compartment to another occurs using built-in pumps. So without electricity, these installations are inoperable.
If the electricity is turned off, bacteria can survive without air for no more than 4 hours, then they die, and the effluent ceases to be processed. To start the system, it is required to be populated with new bacteria, and it is possible to reach a working state only after 2-3 weeks. All this time, the effluents will go, at best, semi-cleaned. This is where a settling well or filter unit comes in handy. It will make things a little better.
Features of operation
Since the volume of autonomous treatment plants is small, they need constant feeding: bacteria need nutrients for normal life. Therefore, such devices are suitable for private permanent residences – regular receipts are needed. In principle, conservation is possible for a certain period, but the procedure is not pleasant, and it will take a long time to enter the installation mode again.
Bacteria that process waste in automatic wastewater treatment plants are also sensitive to active chemicals. Since the volumes of the chambers are smaller, the release of detergents or disinfectants can significantly damage the recycling process. Not only that, it can adversely affect cleaning and treatment with antibiotics.
VOCs are much smaller than septic tanks. They are calculated depending on the daily water consumption, but there is such an indicator as a volley discharge. This is the amount of waste that an autonomous sewer installation can accept at one time. If this value is exceeded, untreated effluents overflow into other chambers, which significantly reduces the degree of purification. So, in this situation, you have to make sure which plumbing fixtures and household appliances work at the same time. And if the bath comes down, for some time no other devices should work.
The choice of pipe slope for sewerage is described here.
Briefly: advantages and disadvantages
Autonomous sewerage treatment plants are certainly convenient, with them sewage for a private house is implemented quickly – installation takes 10-12 hours. Pumping out excess sludge is needed several times a year (1-4 times depending on the intensity of use, but it may be less or more often). The amount of sludge pumped out is quite small (5-10 buckets depending on the model) and maintenance can be carried out independently, although the procedure is not the most pleasant. But they are doing this, since the arrival of a specialist is not cheap at all.
These treatment facilities for the home have disadvantages – this is the high cost of equipment, dependence on the availability of electricity and the need to monitor the condition of the equipment.
Sewerage for a private house: which is better
Which sewage system is better for a private house – a septic tank or an AC – it is impossible to say without reference to specific conditions. Different soils, location of groundwater, stability of power supply. All this affects the choice of the optimal solution. Let’s look at the most common situations.
- The electricity goes out frequently. If there is no backup power source (battery, generator), the use of individual treatment stations is risky – bacteria can die, and refueling them every time is an expensive pleasure, and the station takes a long time to reach its operating mode. Therefore, in this case, it is better to install a septic tank.
- House of periodic residence (country house or cottage). In this case, it is also better to put a septic tank – it normally tolerates different intensity of use, while AUs do not like breaks.
What is better to choose for the sewerage of a private house - Soils “heavy” water leaves badly. In this case, it is better to install VOCs – with a sufficient degree of purification, their effluents can be dumped into the gutter. If desired, you can make bulk filtration fields or filter ditches, under the septic tank and put it. But the arrangement of filter fields in this case requires large areas (and funds).
- High groundwater level. In this case, the installation of VOCs is optimal – the outlet effluents already have a normal degree of purification and they will not cause significant harm, although additional purification is desirable – for complete safety.
- Limited budget. The cost of septic tanks is less than the cost of AC. With a limited budget, it is better to install a septic tank. If money is very tight, you can make a septic tank from concrete rings.
| concrete septic tank | Plastic septic tank | Aeration unit (AU or VOC) | |
|---|---|---|---|
| Dependence on electricity | no | no | a guaranteed power supply is required |
| Tightness | Difficult to seal, especially at high groundwater levels | The hull is sealed, requires anchoring or special fittings | Sealed case, does not pop up (always full) |
| Demanding on the regularity of “replenishment” | Irrelevant | Irrelevant | It reacts badly to uneven flow of effluents, it is better to use it for permanent residence |
| Salvo drop | Works great with large volumes | Works great with large volumes | Handles only a certain amount of stock |
| Service | Regular pumping with a cesspool truck (1-3 times a year) | Regular pumping with a cesspool truck (1-3 times a year) | The machine is not needed, but it is necessary to remove the sludge, as well as wash the installation 1-4 times a year |
| Possibility of self-production | Can be DIY | Factory version only | Factory version only |
| Cost | The cheapest option | Average in price | Expensive |
| Wastewater treatment options | Filter well, sand and gravel filter, infiltrators | Filter well, sand and gravel filter, infiltrators | Filter well, sand and gravel filter, infiltrators, drainage ditch |
As you can see, there is no universal solution. There is a better one for this situation. Properly chosen sewerage for a private house is half the battle. Now it remains to decide on the wiring and ventilation.