1. ProACT™ – an anaerobic process
The ProACT™ tank is divided into two chambers + a distribution well in the centre.
The sewage pipe is connected to the ProACT™ socket for incoming domestic wastewater2 (1), located approximately 100 mm below the upper edge of the tank. This means that the tank must be located at a depth that matches with the placement of the pipe, or alternatively, a separate pumping well must be installed to pump the wastewater to the tank inlet.
Domestic sewage enters the tank’s first chamber where a pre-dissolving process takes place (an anaerobic3 process that can be compared to a natural digestion process). As new wastewater is added, more sludge-containing water will be passed on to the second chamber where it is exposed to a biobed4. The micro-organisms in the biobed degrade remaining organic sludge to a level where it can easily be passed on to the next step in the process. After passing this first biobed, the wastewater is led into a distribution well mounted in the center of the tank. As new wastewater is supplied from the drain, the water in the distribution well rise gradually and passes through a second biobed. Here more naturally occurring micro-organisms ensure that the organic compounds are treated further so that the effluent will be fully ready for final processing in the InterACT™. In the distribution well there is a submersible pump that gradually dispenses the pre-treated wastewater using a specific algorithm with up to 100 l/h on to the InterACT™. Depending on differences between inflows and outflows, the level in the ProACT™ may vary between the minimum level and up the maximum level, 700 litres above the minimum. As acontigency for e.g. power outages, there is a spare capacity of at least another 700 litres on top of the maximum level
2. Connection from ProACT™ to InterACT™
It is essential that the ProACT™ is placed at such depth that the outlet is located 30-200 cm lower than the inlet of the InterACT™ (smaller level difference could jeopardize the reflow after the pumping cycle, whereas greater level difference requires a more powerful pump – can be done at an additional price).
There is one connection between ProACT™ and InterACT™. The connection is located so that, if correct, it falls from the InterACT™ to theProACT™ (this is so that water does not stand inside the tube between pump cycles, but flows back to the PROACT™ – risk of freezing!). This pipe has to be of a flexible construction.
3. InterACT™ – Aerobic process5
The InterACT™ tank is divided into a main chamber, “basin cavity”, a chamber of oxygenation and flow control and a distribution well in the middle.
The pre-processed wastewater is pumped from the ProACT™ to the inlet pipe of InterACT™ gradually and in portions according to a certain algorithm in the micro-computer unit. The inlet exists near the bottom of InterACT™- to what we call the “basin cavity”. Here the water circulates at a speed of up to 2 m/s. The circulation is ensured through an air pump that creates a natural swirled water flow (Vortex flow) while the water is optimally oxygenated. In this free circulating area, a separation of organic matter takes place. Since the organic matter is lighter than water, it rises and is exposed to the biobed located above the bottom. The micro-organisms in the biobed convert the organic matter into plant available nutrients. On top of the bio-bed there is a plant bed consisting of a specific set of aquatic plants. Through the roots that grow down into the water the plants absorb the nutrients that the system makes available. In this way, undesirable substances are transformed and degraded completely biologically.
As new wastewater enters, the water that has reached furthest into the “basin cavity” is led into the distribution well where it passes through another biobed placed above the bottom. Above this biobed there are a few hundred litres of water with a layer of Leca balls. The Leca balls float on the surface and are used as carriers for the plants that grow in the middle of the tank. These plants, together with the biobed, account for another step in the biological purification process.
The outlet pipe goes through the Leca balls and further down in the biobed of the distribution well. Since all parts of the tank are in hydraulic contact with each other, the outlet will in practice be controlled by the level in the tank, that is as much wastewater supplied, as much purified water is drawn off.
The end result is that unwanted substances in the wastewater are transformed into a lush greenery and biodiversity. This process broadly agrees with nature’s own purification process.
4. The outlet
The outlet pipe is installed so that the effluent drains completely and no water is left standing in the pipeline. If water is left standing in the pipe there is a risk of freezing at low temperatures. (In case of difficult conditions or extreme cold, the pipe can be provided with a self-regulating heating cable to eliminate the risk of freezing).
5. The purified water
The water that is treated in the ACT Natural™ process is naturally purified with very low residual BOD6 levels. This means that the water is odourless therefore it can be reused, for example for irrigation, filling of ponds or flushing the toilet.
6. Process equipment and electrical connection of the system
The ACT Natural™ system is based on Nature’s own processes and therefore contains a minimum of technical components. There are no electrically operated valves and no moving “level switches” or similar. The technical processing components are restricted to:
- 1 sewage pump
- 1 air pump
The ACT Natural™ system is controlled by a microcomputer mounted in a control box. This control box contains everything needed to control and monitor the system and, in case of an abnormality, generates an alarm. The control box is normally placed in the ground in association with the InterACT™. The control box contains a small thermostatically controlled heating system that ensures that no condensation is formed in the box. In the control box there is also a main switch to enable service without needing to disconnect the power supply inside the house. The system is connected with an underground cable 5G1. 5 to 230 V e.g. in the dwelling house. The alarm light, that is included in the system to warn of any abnormal operating conditions, is also installed inside the house. To ensure that the alarm comes on in case of power failure due to a blown fuse, the alarm should be fed from another group in the main distribution box than the one feeding the control box.
7. Polishing step for additional phosphorus removal
In some cases a subsequent polishing step for additional phosphorus removal may be required. If so, this is established after the InterACT™ and in accordance with the recommendations that apply to the selected phosphorus trap.
2 Domestic wastewater is all sewage that leaves the house, thus both grey- and blackwater
3 An oxygen free process
4 The biobed consists of assembled ”worms” constructed so that the micro-organisms have a very large effective surface area (up to several hundred m2 with micro-organism per m3 of biobed)
5 A process that requires oxygen supply
6 Biochemical Oxygen Demand