All biological wastewater treatment plants have the following technological parameters:
Concentration of primary characteristics in purified water:
| Type | CODCr** | BOD5* | Floating material | N-NH4 | Ntotal | Ptotal |
|---|---|---|---|---|---|---|
| A.B.Clear Plants
Typical Emission Values |
55 mg/l | 15 mg/l | 18 mg/l | 9 mg/l | 20 mg/l | 5 mg/l |
Above data was taken from the final report of the VITUKI analysis. The quality of purified water corresponds to area category 3. in annex 2. of KvVM decree No. 28/2004. (25.12.), applicable to periodic water-course outlet.
*: BOD5 - The BOD (Biochemical Oxygen Demand) value represents the amount of oxygen consumed by a mixed bacterial culture, under near optimal physiological conditions while they decompose biochemically degradable organic matter contained in the water. Currently the most general method of specifying the BOD value is: BOD5 (mg/l), which represents the biological oxygen demand consumed in the course a five-day analysis of one liter test sample, expressed in mg O2, normally at 20°C, in complete darkness.)
**: COD - Depending on the rate of contamination, waters contain such organic, floating and dissolved materials, which can be oxidized with strong oxidants (e.g. with permanganate, dichromate, etc.). The rate of organic contamination of waters, the organic contaminant content is expressed with the amount of oxidants consumed during their oxidization under standard conditions, or with the equivalent amount of oxygen. This is called Chemical Oxygen Demand (COD), expressed in units of O2 mg/dm.
Accordingly, the quality of purified water corresponds to applicable regulations. A more rigorous quality can be achieved with the use of a sand filter or by adding chemicals.
Positioning of a domestic-scale biological wastewater treatment plant:
The biological wastewater treatment plant is placed into a pit dug in the ground, on a 15 cm thick blinding layer of concrete, so that the top of the tank is 5 cm above the ground level. If site conditions require, the bottom part around the tank is also filled with concrete (this is mostly necessary in case the level of subsoil water is higher). The wastewater treatment plant needs to be filled up with water up to the height of the effluent pipe, before soil is refilled back around the tank.
Primary technical conditions for application of a biological wastewater treatment plant:
- electricity line wired up to the wastewater treatment plant ;
- fitting of connection pipes up to the wastewater treatment plant, right below the ground level of freezing;
- determining the subsequent course of water, whether water can be desiccated depending on surrounding conditions, it can be utilized for root infiltration or filled into live water;
- ensuring the level of reception of the biological wastewater treatment plant;
- in case of high subsoil water levels, a concrete basin needs to be developed around the plastic tank of the wastewater treatment plant with a wall 30 cm higher than the highest subsoil water level;
- the amount of slowly degrading (so-called persistent) contaminants let into the system should be kept on a minimum level, or avoided all together, as possible. The biological degradation of such materials is not possible. Such are pesticides, solvents, colorants, certain detergents, aromatic compounds with chlorine. The presence of these materials in household wastewater can be avoided, while larger amounts can cause problems in the system, which will also void the warranty;
- due to its configuration, there is only a very low chance for malfunctions in case of the biological wastewater treatment plant, namely in relation to the compressor or the controller unit.
- In case of designated use, we provide a two-year warranty for our plants.
About trickling:
Trickling, or desiccation is the easiest way of reusing purified wastewater. The GRAF® desiccation unit is a product developed for the desiccation and retaining of water.
Water trickles into the soil through an underground tunnel system. The unit was developed so that it can be placed near the ground surface, even under roads with vehicle traffic.
The main components of the desiccation system are a tunnel unit, two end pieces and geotextile, one end connected to the effluent of the rainwater tank, routed underground with a slight slope, ending in a special, vertical vent pipe reaching above the ground level. It is recommended to develop an at least 30 cm thick ballast bed under the trickling system.
It is very important, that in case of a biological wastewater treatment plant, there are major differences in the development of the desiccation system compared to that used for rainwater!
In case of soil with a good water absorption ability, for example sand, 3 tunnel units will suffice. If soil is clayey and absorbs water slowly, a much longer system will be necessary.
