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the total flow to be treated at a WTP situated in a nearby field and then used for irrigation. |
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The total cost of phase A was estimated at almost Dr. 17 millions. |
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Problems were encountered when trying to locate an appropriate site for the WTP. The main reason for this was the local people's unfortunate experiences with the existing sewage disposal system, and their reluctance to sanction the construction of a treatment plant close to the settlement. (Specifically, there is a conventional sewerage system collecting wastewater from a large area of Oia. The collected wastewater flows by gravity to a field in the north part of the island. After primary settling in a series of closed, poorly constructed rectangular tanks the wastewater overflows and creates an unpleasant, mosquito-infested anaerobic pond which overflows directly to the sea.) |
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The original design was amended by the Technical Services Department of the Cyclades Prefecture in the following respects: |
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pipe material to be PVC with a minimum diameter of 125 mm. Only a small part of the network (110 m) was to be constructed in 110 mm diameter HDPE pipe, for demonstration purposes; |
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inspection chambers to be a special commercial type, located every 50 m and covered with a heavy duty lid; and |
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the pipes of the whole network to be protected with a 70 mm thick cement collar (this was in spite of the fact that the heaviest traffic is the donkey). |
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The cost increases caused by these alterations was offset by the fact that PVC pipe is cheaper than HDPE pipe. |
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The second phase of the project focused on the optimal layout for the sewer network, and connecting the new system to the existing conventional sewer network. |
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The final pipe layout within the settlement retained only one of the pumping stations. The total flow was to be pumped via new pumping stations to the existing conventional sewerage system. |
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