Recommendation points
- What is the difference between a septic tank and VOC and how does it work?
- How many cameras should there be?
- What is aeration and sludge pumping for?
- How to determine sufficient volume
- Is it possible to install a septic tank with a high GWL
- How far from home can a septic tank be placed
- Can a septic tank freeze
- Does a septic tank spoil groundwater
- Do you need additional bacteria and what
- What to do if there is a smell
- How often should the septic tank be cleaned
- How to dispose of waste sludge
- How to use purified water
- What to do if a septic tank is leaking
- Why does the septic tank overflow
Despite the fact that biological treatment septic tanks entered the market a long time ago, a fairly small circle of people have an idea of these facilities. As an educational program, we propose to answer most of the typical questions about the selection, installation, operation and maintenance of septic tanks and VOC.
What is the difference between a septic tank and VOC and how does it work?
In short, a septic tank does not provide a sufficiently deep degree of purification. At the exit from the local treatment facilities, the water is ready for discharge into public water bodies, it is disinfected and practically does not contain mechanical impurities. But in the case of cleaning with a septic tank, the drains are simply clarified, while the opacity of the water at the outlet or the presence of odor is possible. The septic tank is based on biological treatment. Many species of bacteria use organic waste as a breeding ground, gradually recycling the effluent to form water, gases and mineral sludge. But this is just one of the stages of purification of high-grade VOCs..
How many cameras should there be?
It depends on the goals and purpose of the septic tank. In the simplest case, one chamber is enough, in which anaerobic bacteria perform cleaning, but this way the amount of sludge at the outlet will be greater, and the clarified water cannot be discharged directly into the filtration field. If the septic tank has two chambers, water will settle in the second and over time it can be discharged into the filtration field or into a drainage well. In other words, the more chambers a septic tank has, the less the effluents entering it pollute the already clarified water. On the other hand, there are current standards of SP 32.13330.2012, according to which single-chamber septic tanks cannot be used with an estimated number of residents of more than five (upon receipt of up to 1 m3 wastewater per day), and two-chamber – no more than 50 residents and inflow up to 10 m3 per day.
What is aeration and sludge pumping for?
The presence of the so-called aeration tank in the septic tank allows you to expand the set of biological species of microorganisms, including aerobic bacteria in the work. They allow to speed up the process of wastewater treatment, but for this their habitat must be saturated with oxygen. But one interesting incident is associated with aerobic bacteria: at a certain moment their population becomes so numerous that food reserves are exhausted and the colony simply dies out. To restart the aeration tank, a part of the activated sludge from the primary settling tank is added to it. Also, the sludge pumping system allows you to remove the spent mineral residue and accumulate it in one container, thereby facilitating the cleaning of the septic tank itself.
How to determine sufficient volume
The capacity of a septic tank is determined by the number of people living in the house, household habits and lifestyle. You can build on the readings of the water meter, you can take the norm of 200 liters per person per day as a guideline. At the same time, the capacity of the septic tank should allow the drains to have time to be cleaned sufficiently, which takes at least 3 days according to building codes and from two weeks for sanitary ones. In fact, the best option would be to entrust the calculation of the septic tank capacity to the specialists of the manufacturer’s company..
Is it possible to install a septic tank with a high GWL
Groundwater can really squeeze a septic tank out of the ground, because its bulk density is less than that of the ground. However, if the fact of a high GWL is known in advance, nothing prevents you from choosing the appropriate installation technology. So, a septic tank can be installed inside a concrete caisson, backfilling of the pit sinuses can be done with hygroscopic gravel, and the septic tank can also be simply rigidly fixed on a concrete slab that acts as a ballast. It is only important not to allow the groundwater to rise above the neck of the septic tank, this will inevitably cause its flooding.
How far from home can a septic tank be placed
According to building codes, the minimum distance between the outer wall of the foundation and the body of the septic tank is 5 m. In practice, the removal of the septic tank is rarely less than 8-10 m, this is how you can ensure that there are no unpleasant odors in the residential area. The maximum removal is not regulated by anything, however, you need to remember about the slope rate of external sewage pipes of 2–5 mm / m. If the septic tank is removed too far, its throat may be lower than the GWL.
Can a septic tank freeze
The septic tank is filled with water, and therefore – yes, theoretically it can be frozen. However, do not forget that most septic tanks are installed below the freezing depth, moreover, due to the constant biological activity of the effluents, they serve as a source of heat. If the septic tank is located in a freezing layer of soil and at the same time the flow of drains is irregular, it is better to equip a thermal protection belt, for which the cheapest foam is ideal.
Does a septic tank spoil groundwater
Potentially in the protective zone of the septic tank, contamination of the upper water is possible. But this applies mainly to septic tanks, which were installed in violation of elementary norms, as well as filtration fields and drainage wells, the construction of which did not take into account the geomorphology of the site. Also, do not worry about damage to water sources located more than 30 m upstream from the treatment plant and from 50 m in other cases..
Do you need additional bacteria and what
In general, the greater the biological diversity of microorganisms in the septic tank, the deeper and faster the wastewater treatment will be. However, it is important to remember that some bacteria can completely displace others, and also that due to the overactive development of the colony, it simply may not have enough nutrient medium. All kinds of biological additives for a septic tank can be used, for example, for a quick start after a winter downtime or in case of clogging of chambers with unprocessed sludge. The effectiveness of certain bacterial additives is best determined empirically, because the composition of the effluent in each septic tank is different.
What to do if there is a smell
It is normal for a septic tank to occasionally develop an unpleasant odor during operation, but a persistent, foul-smelling atmosphere is a clear sign of malfunction. The main reason is the death of the bacterial colony and the suspension of processing due to the appearance in the septic tank of a high concentration of destructive chemistry. In most cases, the work of the septic tank is restored in 2-3 weeks by itself, the process can be accelerated by introducing additional bacteria. Do not forget about the importance of installing a waste riser to remove secondary gases, this also applies to drainage wells and filtration fields.
How often should the septic tank be cleaned
As it gets dirty. The septic tank should be checked at least once every 2-3 weeks, the fullness of the chambers, the presence and amount of non-sinking suspension should be assessed, the bottom should be pinned to shake up the settled sludge. Subject to the rules of installation and operation, a septic tank in one period between purifications can pass a quantity of wastewater that is 3-5 times higher than its own volume.
How to dispose of waste sludge
There are two options in total. The first is to call a sewer truck, which will completely drain the septic tank, taking most of the sludge from the bottom. If access to the septic tank is not possible or the services of vacuum barrels are not affordable, the waste sludge can be removed manually and either stored in a compost pit, covered with plant residues, or spread openly over the soil. It is only important that the sludge is really spent; for this, it is better to limit the flow of effluents into the septic tank for a while.
How to use purified water
It depends on the degree of cleaning. It is important to remember that claims to remove 98% of impurities are an absolute myth. It is the bacterial contamination of the outlet water and the presence of an unpleasant odor that is important. Most home-made septic tanks require a final post-treatment through the ground or a drainage well. At the outlet of factory-made septic tanks, there may indeed be slightly turbid odorless water, but it is still not worth dumping it openly. Water from a septic tank can be used for irrigation only in very rare cases..
What to do if a septic tank is leaking
If a leak is detected in a septic tank, its work must be stopped immediately. If we are talking about a branded product, the manufacturer’s specialists should be involved in the repair. Homemade septic tanks need to be cleaned, partially excavated and repaired, eliminating gaps in waterproofing.
Why does the septic tank overflow
There are only two reasons: either the capacity was initially incorrectly calculated, or a malfunction occurred. If only one or two of the first chambers are filled in the septic tank, it can be assumed that the overflow pipes are clogged. If the septic tank is completely flooded and the fact of raising the groundwater is excluded, most likely the matter is in the blockage of the drainage pipe, through which the clarified wastewater is discharged from the septic tank.
Could you provide more information about septic systems and VOCs? I’m interested in understanding their relationship and potential impact. Are there any specific concerns or risks associated with VOCs in septic systems? How can VOCs be managed or mitigated in relation to septic systems? Thank you for clarifying these aspects!