In the course of planning individual wastewater treatment, the question whether to invest into a septic tank or a biological wastewater treatment plant is often raised. The two systems differ in essence, primarily due to the fact that the septic tank does not have to be aerated, while the biological wastewater treatment plant does. Accordingly, the septic tank does not use electricity, but otherwise it has no further advantages, while biological wastewater treatment has plenty of benefits.
- Cost of realization: little difference between the two solutions, but septic tanks require a much larger trickling system, than the biological wastewater treatment plant.
- Cost of maintenance: septic tanks need to be sucked from time to time, which can be rather costly, while in case of a biological wastewater treatment plant this is not needed. The septic tank does not use electricity, but for proper operation the bacteria culture has to be renewed continuously, while as a result of aeration, this is not necessary in a biological wastewater treatment plant, and the monthly cost of electricity consumption of a plant is only around HUF 1,000-2,000 per family.
- The principle and efficiency of purification: Septic tanks realize mechanical and anaerobic (without air) purification, while aerobic (in the presence of oxygen) processes take place in the trickling system, also with a very low efficiency. In a biological wastewater treatment plant all of the above processes, i.e. mechanical, anaerobic and aerobic processes take place within the tank, the same way as in the case of wastewater treatment plants of cities, and this results in the highest efficiency of purification. In the latter case, the quality of purification can be directly measured after the effluent pipe, while in case of septic tanks it cannot, as aerobic decomposition takes place in the desiccation trench.
- Maintenance: Septic tanks need to be sucked out on regular basis, and the resulting sludge is hazardous waste, and due to the lower efficiency of purification, the trickling pipes can get clogged sooner. In case of a biological wastewater treatment plant there is no need for sludge suction, sludge can be removed from the plant in a dewatered, easy-to-handle form (in a bag) and can be used for composting, as it is not hazardous waste. Furthermore, the strainer of the air pump has to be cleaned 3-4 times a year, and replaced every couple of years.
- Can purified water be reused? It is not suitable for human consumption! Without further purification, it can only be used for root irrigation (trickling), or for watering plants. In case of an irrigation system, a filter (geotextile drum filter) has to be fitted so that particles floating in the water do not damage the irrigation system. For use in toilets or other household applications, sterilization cannot be realized economically at present, due to the low quantities produced. In case you wish to have the purified water sterilized with UV-light or ozone treatment, that is possible, but one should consider, that such an investment will not be returned.
- Obtaining permits: Since verification of the quality of purification is difficult, obtaining a permit for septic tanks is often problematic. Pursuant to government decree No. 147./2010. owners of septic tanks must prove by means of presenting invoices, that suction of the tank was carried out, i.e. they must ensure the removal and disposal of the resulting hazardous waste. Issuing a permit for an individual biological wastewater treatment plant is the authority of the registrar, if the annual output of the system is less than 500 cubic meters, the plant has a CE certificate (all A.B.Clear equipment is CE certified), and purified water is not released into surface waters. Provided that this is the most improved technology available, it is often supported.
If operated correctly, there are no disturbing smells, as due to continuous aeration, sewage does not start rotting, as in case of sumps, or systems, which are not aerated. In case of an individual, biological wastewater treatment plant, a sour smell indicates incorrect functioning.
A biológiai szennyvíztisztító elsősorban kommunális, tehát lakossági szennyvíz tisztítására készült. Ebbe beletartozik a WC-ből származó összes szennyvíz (feketevíz), valamint a háztartás egyéb folyékony hulladékai a tisztálkodásból, takarításból, mosásból, mosogatásból, stb. (szürkevíz). Ezeket a szennyvíztisztító újrahasznosítható vízzé alakítja. A vegyszerhasználattal kapcsolatban lásd a részletesebb bekezdést lejjebb! A berendezésbe tilos olajszármazékokat, festékeket, hígítókat, megmaradt gyógyszereket (főként antibiotikum), ételmaradékokat, sütőolajat, és egyéb, vízben nem oldódó szilárd anyagokat (műanyag, szövet, fa, fém, stb.) önteni, ezek a baktériumkultúra pusztulásától kezdve dugulásokon át akár a berendezés fizikai károsodását is okozhatják!
- The biological wastewater treatment plant is primarily for the purification of communal, household wastewater, not for the treatment of public sewage. This includes all wastewater from toilets (black water), and other liquid wastage of the household from personal hygiene, cleaning, washing, dish-washing, etc. (gray water). The wastewater treatment plant purifies these into reusable water. In connection with use of chemicals refer to the more detailed description below! It is prohibited to let oil products, paints, thinners, left over pharmaceuticals (antibiotics in particular), food residues, frying oil and other solid materials, which do not dissolve in water (plastic, textiles, wood, metal, etc.) into the treatment plant, as in addition to the elimination of the bacterial culture, these can cause clogging and other physical damaging of equipment!
- In case of using a biological wastewater treatment plant, the use of biodegradable detergents is recommended for several reasons. Firstly, such naturally degrading materials do not damage the micro-flora within the plant, which performs the purification process, and secondly, these degrade fast after they are released into the trickling system or the soil, thus no hazardous chemicals are released into the environment. The same is true in case the purified water is filled into live waters.
Considering that the plant is completely enclosed and normally no liquids are released from the tank, it can be placed as close as 2 meters from the building, but – mostly in case of small-scale wastewater treatment plants – the recommended distance is up to 10 meters. This distance cannot be exceeded, as in case of a colder winter, wastewater can cool down even below the ground level of freezing, so that it inhibits the course of biological processes, thus the quality of purified water will fall below the desired level.
- It is not suitable for human consumption! Without further purification, it can only be used for root irrigation (trickling) of plants. According to regulations, further, more costly post treatment is necessary for reuse in toilets (chemical treatment – membrane filter), which investment is not returned in general on a household scale.
The wastewater treatment plant itself, which is a sealed tank, does not release any purified wastewater or other materials into the environment, thus it may be set up even directly next to a fresh-water well. Purified water is only released into the soil from the trickling system, while the desiccation trench has to be developed at an adequate distance from the well. In case of wells, where the water is obtained from a safe depth from beneath impervious layers (drilled well), trickled water does not influence the quality of the fresh-water in the well.
No it is not, as the tank is made of plastic, so it is not strong enough to carry the weight of a vehicle. The building of neither a paved road, nor a sidewalk is allowed above the tank, and the tank should not be buried with ground either. The possibility of opening and accessing the plant must be ensured in all cases!
Not necessarily. Taking a six-person capacity plant as an example, if the guests use the wastewater treatment plant for only 2-3 days, because they sleep over, and the overall number of users in these cases is around 9-10 persons, then it is not worth installing a 10 person capacity system. Our wastewater treatment plants can typically take even a 150% load for a period of 2-3 days with no changes in the quality of the purified water, without causing sour smells or malfunctions, or clogging. When normal load is reinstated, the biological system also returns into its balanced state, and continues to operate unchanged. However, in order to avoid problems, you must inform your guests about what they are allowed to, and not allowed to throw into the toilet, for example!
Yes. The system can also be used in case of holiday houses, as described in the following. If the holiday house is used on weekends, then use of a microprocessor controller unit for the air pump is definitely recommended. This allows the setting of an low load operation mode. This is needed, as in case of a constantly low load, too much aeration will adversely affect the quality of operation. In cases, when the holiday house is used as a constant residence from spring to autumn, and it is not used at all during the winter, the plant can be used normally during warmer months, but at the time of moving out in autumn, the system has to be shut down. The biological system cannot take several months without any nutrients. Accordingly, the system has to be prepared for winter; its entire contents have to be sucked out (which also removes excess sludge), and it has to be filled up with pure water. It will not freeze, crack or break, as the water level is below the ground level of freezing. When moving in during spring, the system has to be commissioned again, after which it can be used normally.
Plants, which do not require aeration, have the advantage that they do not need electricity, they are not affected by a black-out, nevertheless, their operation is essentially different. The plant itself only realizes airless (anaerobic) decomposition, which means that wastewater actually starts to rot, and that is how the contaminants degrade. In such systems, aerated (aerobic) decomposition takes place in the trickling system, with lower efficiency. For this reason, these systems require a much larger desiccation area (a large area has to be dug up), than the aerated systems sold by ÖkoTech-Home Kft., and the treatment technology also fails to allow the sampling of purified water. This makes the obtaining of a permit for non-aerated systems – especially in areas under natural protection – rather difficult. Furthermore, due to the lack of aeration, the bacterial culture has to be continuously refilled, while in case of an artificially aerated system, the biological balance is maintained. The electricity demand of aerated systems is no more than 36-40 kWh on a monthly basis, and with a microprocessor controller unit, the half of this (around HUF 1,000-2,000 per month), while water quality is constant and obtaining a permit is also a whole lot easier. There are also moving-bed type systems, which ensure adequate purification, when installed downstream from the septic tank, however the level difference between the inlet and discharge is significant, so in this case it is the pumping of water back up, what consumes electricity.
A part of bacteria within the plant is kept alive by aeration, making it the most critical part of the system. It depends on the duration of the black-out, whether the system is capable to reinstate its balance, or not. This duration is also influenced by the time of year (season). During winter, when water is colder, bacteria are less lively, so they can take even 3-4 days without aeration, during the summer, when their metabolic processes are faster because of the warm weather, this is decreased to as little as 1-2 days. After aeration is restarted, you should regularly inspect the condition of water purified by the system (visually), and pay attention to any unwanted odors! In case the normal state has obviously been reinstated within up to 1-2 weeks, and the plant does not emit a sour smell, then the system functions properly. If water turns turbid, and the plant emits a gradually stronger smell, which does not lessen even after aeration is restarted, then the biological balance has been lost in the plant. In this case the plant has to be completely sucked out and restarted with a fresh bacterial culture.
The inlet depth of the biological wastewater treatment plant is below the ground level of freezing. If the sewer pipe from the house is much deeper than the inlet pipe of the wastewater treatment plant, then the plant has to be placed as deep as necessary, and a raising block has to be placed over it. In many cases - depending on the location - terrain conditions cannot be corrected enough, so that no extension is needed. The raising block can only be 45 cm; in case of a level difference exceeding this, an intermediate tank will need to be installed and the continuous operation of a sewage pump will be required.
The A.B.Clear 6 & 8 wastewater treatment plants were designed so that the bottom of the inlet pipe is at 51 cm from the top of the plant. Without a raising block, this can be connected to a sewer pipeline running up to 46 cm deep. In case of a sewer pipeline runs deeper than 75 cm, an intermediate shaft has to be developed before the plant. Due to their specific design, the A.B.Clear 10-50 plants are dimensioned differently, but the exact dimensions of the sewer pipe outlet are equally important. In case before an on-site consultancy you do not have information about where and how deep the sewer pipe exits the building, positioning of the plant on the given plot may not be determined on-site either.