TITLE:Sewage Network Completion Study – Updating of the Preliminary Study of the Wastewater Treatment Plant of Hydra and Environmental Impact Assessment
NAME OF CLIENT:Region of Attica, Regional Unit of the Islands
TYPE OF SERVICES PROVIDED:WWTP Preliminary Study and Tender Issues.
Sewage Network, pipeline and pumping stations Final Study with Tender Issues.
DATES (END):2015
PLACE:Hydra, Region of Attica
DETAILED DESCRIPTION OF PROJECT:The study of the construction of sewage networks includes the completion of the Hydra settlement networks.

The WWTP was designed to serve the Hydra settlement population for a period of 20 years (10,000 equivalent inhabitants in summertime) and 40 years (14,000 equivalent inhabitants in summertime).
The WWTP consists of the following projects and processing stages:
• Adduction Works: Includes initial lifting pumping station and the wastewater depressing adduction pipeline.
• Entry Works: Includes an input shaft with sloughing layout.
• Pretreatment Works: The pretreatment works include provisions for sloughing, desanding and primary settling.
• Biological Step: Consists of microorganisms collection tanks, phosphorus biological removal tanks (anaerobic tanks) denitrification tanks (anoxic tanks), aeration tanks, sedimentation tanks, mixed liquid and excess sludge pumping recirculator.
• Disinfection and postaeration Works: Will include chlorination and dechlorination tank and postaeration well with all the required facilities for chemical dosing and aeration.
• Flow measurement works.
• Sludge treatment works: includes devices for mechanical thickening and mechanical dewatering of excess sludge.
• Output Works and disposal of treated wastewater: Includes charging well and the distribution pipeline for treated wastewater.