Vioka of Avrami Lefkochora
Completion of the project “Collection, transport and treatment of wastewater in T.D. Avramiou – Lefkochora (Section 2) “” with a total budget of € 2,607,000.00. The project was funded by DEPIN 2007-2013.
a) Type and size of activity
OPERATION DESCRIPTION OF THE INSTALLATION
Proposed Sewerage Projects
Settlement of Lefkochora
Sewage collection will be done with a network of gravity pipes and visit-maintenance wells. The main pipeline of the settlement consists of PVC pipes Φ200 and has a total length of approximately 1350 m and 44 wells. The secondary and tertiary gravity pipe network also consists of PVC Φ200 pipes with a total length of 1200 m and 46 additional wells.
All the sewage of the settlement is transported by PVC gravity pipeline Φ200 up to a point that is 370 m away from the treatment site. From this point the sewage is pumped to the installation with a push pipe. The length of the gravity pipeline from the settlement to the pumping point is about 400 m.
Settlement of Avrami
Due to the relief it is not possible to collect sewage simply by gravity. Thus, in addition to the gravity network, two sewage pumping stations will be required. The internal gravity network of the settlement consists of PVC pipelines Φ200 with a total length of 2000 m and 83 visit wells.
Two thrust pipes carry sewage from the lowest to the highest points of the network. The total length of the push pipes is 750 m made of PVC pipe Φ90 10 atm. The pumping pressure is estimated to be in the range of 15-20m.
The transfer of sewage from the settlement to the EEL is done first with a gravity pipeline and then with a push pipeline. The gravity pipe has a length of 670 m and is made of PVC pipe Φ200. 17 visit wells are placed in the pipeline. The wastewater is collected in a pumping station and with a push pipe is led to the grate well of EEL. The thrust line has a length of 750 m and is made of PVC pipe Φ110 10 atm. The pumping pressure is estimated to be about 6-12 m.
For the design needs of the facilities, 1000 people are taken as the future summer population (20 years old).
The proposed installation consists of the following parts:
1 • Grid (Engineering – self-cleaning)
2 • Primary subsidence
3 • Mud collection and storage
AD stage of beds of aquatic plants of vertical flow
1 • B stage of beds of aquatic plants of vertical flow
2 • Maturation
3 • Disinfection
Sewage from the settlements of Avrami and Lefkochora reaches the pumping well of the installation. It is a double well with the possibility of communication of its parts. This is done to distribute the supply on two racks. Two cylindrical rotating drills of thin slit are installed to receive the peaks. The grills operate with minimal energy consumption and the solid grilles end up in a perforated bucket where they are initially dehydrated. They are then emptied on a flat surface for further dehydration and finally pushed and stored in a trash can.
A third is provided between the two inlet wells where the principle of the general bypass pipe of the installation is adjusted. This pipeline operates in cases of flood but also in cases of maintenance of the grate or the primary sedimentation tank.
In the next stage, the wastewater is transferred to a primary sedimentation tank. The tank is divided into two for ease of operation and maintenance. It is also divided into two sections lengthwise for better fluid clarification and better performance in primary sludge collection. The primary sludge settles and is periodically removed from the bottom of the tank by pumping. It is stored in a separate tank for several months until it is completely stabilized.
Pre-precipitated effluents are taken for secondary treatment to beds planted with aquatic plants, specifically Phragmites Australis. In the beds the dissolved organic load of the wastewater is removed as well as the ammonia is converted (nitrification). Two stages of treatment with beds (flower beds) of vertical flow are proposed.
This is followed by a stage of maturation and further removal of nitrogen. This is done in an open shallow tank without stirring. Finally, clean effluent is disinfected with ultraviolet radiation. The outflow is led by gravity to the Blind Stream that passes near the treatment site.
The stabilized sludge from the storage tanks is pumped to the pre-sediment line, specifically to the siphon well. From there
led to the beds of the first stage of treatment based on a different treatment program from that of the pre-precipitated wastewater. The drains return by pumping back to the outlet of the settling tank for reprocessing. The mud stays in the beds for several years. Its solids are converted into useful soil conditioner (compost).