- Biological WWTP (WasteWater Treatment Plant) with intermittent treatment technology
- It consists of a dividing object, a pair of activation tanks, a pair of sludge tanks, and an emergency tank
- The operation is controlled by a microcomputer that adjusts the treatment mode depending on the quantity and quality of incoming water
- Generally designed for a capacity above 500 Population Equivalents (PE)
Construction Solution
All tanks are usually rectangular and grouped into a single building which can be roofed according to the investor’s requirements. The wastewater treatment plant then takes on the character of a rural agricultural building. The tanks can also be left open reducing construction costs in this case.
Advantages of the Technology
- With sufficient tank sizing, high-quality treated water is ensured at the outlet (BOD5 10-20 mg/l), nitrification, denitrification, and partial phosphorus removal are provided
- The operation is fully automatic and can be monitored remotely
- In case of a failure in one of the reactors the other of the pair ensures the flow through the treatment plant without interrupting the treatment process. This prevents undesired overflow of untreated wastewater through the treatment plant
- Low operating costs
- The WWTP is suitable for biologically treatable industrial wastewater as well
Description of the Technological Line
Wastewater first enters a coarse pre-treatment unit where it is rid of sand and other coarse impurities using fine mechanical screens. The pre-treated water flows into a distribution tank with separate filling equipment for each of the pair of reactors.Once a reactor is filled all the set treating processes take place in a single tank, including biological nitrogen removal, organic pollution reduction, and partial phosphorus removal. Subsequently the reactor enters a resting phase. After settling of activated sludge the treated water is decanted and excess sludge is pumped to the sludge tank. This completes the cleaning cycle and the reactor is ready for the next filling. Both reactors operate alternately in regular cycles.
Depending on the amount of incoming water the operation can be optimized over a wide range (10 – 200%) of the designed capacity.
At low flows, only the amount of water needed to maintain optimal conditions for the biological process remains in the system, automatically reducing electricity consumption. At higher flows, the total duration of the treating cycle is shortened so that the second reactor is emptied before reaching the maximum level in one of the pair of reactors.
Technological Scheme
| Type of WWTP | Size of WWTP | Flow | Load | Construction Dimensions1) | Operating Level2) |
|---|---|---|---|---|---|
| PE | m3/day | kg BSK5/day | [m] | [m] | |
| FL 500 | 500 | 75 | 30 | 16 x 8 | 2,5 |
| FL 1000 | 1 000 | 150 | 60 | 20 x 10 | 3,0 |
| FL 1500 | 1 500 | 225 | 90 | 25 x 12 | 3,0 |
| FL 2000 | 2 000 | 300 | 120 | 26 x 13 | 3,5 |
| FL 2500 | 2 500 | 375 | 150 | 29 x 14 | 3,5 |
| FL 5000 | 5 000 | 750 | 300 | 39 x 19 | 4,0 |
| FL 10000 | 10 000 | 1 500 | 600 | 53 x 26 | 4,0 |
| FL 15000 | 15 000 | 2 250 | 900 | 66 x 28 | 4,5 |
1) The mentioned construction dimensions are only indicative. For each project, they can be adapted to the specific spatial situation and the technological requirements of the customer.
2) This refers to the commonly used working level which can be adjusted according to the customer’s specifications and the size of the WWTP within the range of 2.5 – 5m. The total depth of the tanks is 0.7 – 1 m higher..
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