Project Summary

Wastewater Management

ENVIRONMENTAL IMPACT ASSESSMENT AND PREAPPROVAL PROJECT LOCATION STUDY FOR THE PROJECT “WASTE WATER TREATMENT PLANT OF THE COMMUNITY OF PETHELINO WITHIN STRIMONA MUNICIPALITY, SERRES PREFECTURE" ADOPTING THE TREATMENT METHOD OF ARTIFICIAL WETLANDS

Client: Municipality of Strimona (Neos Skopos), Prefecture of Serres
Year:   2001

ISSUE
The aim of the project was the preparation of the preapproval project location study and the Environmental Impact Assessment for the construction of the Waste Water Treatment Plant (WWTP) in the community of Pethelino of Municipality of Strimona.

SOLUTION
The WWTP is located 2km south of the community at the junction of ditch Pethelino and the artificial river bed of Strimona and is situated in a field which occupies an area of 1 hectare.

The community of Pethelino has an internal sewer network with a total length of 8km and pipeline diameter of 400mm. Wastewater is collected in a central pipeline collector and eventuates in the WWTP for treatment via an external sewage network of 400mm diameter pipelines.
The WWTP of Pethelino was designed to serve approximately 500 equivalent residents. The design of the facility was based on the following data:

Parameter	Measurement Unit	Value
Population	persons	500
Average Flow	m3/d	12

The WWTP which treats incoming untreated wastewater, consists of the following stages:

• pre-treatment which comprises of bar screens and flow measurement
• primary treatment which takes place in four beds filled with inert material and planted with A grade plants
• secondary treatment which takes place in one bed filled with inert material and planted with B grade plants
• decontamination and storage of treated wastewater, which takes place in maturation lakes (artificial lakes) with a depth of 1.5m
• disposal of treated wastewater which is accomplished via an overflow pipeline from the maturation lake to the chlorination tank and then to the final recipient

The excavation of the surface flow beds was accomplished at a depth of 0.5m with a slope incline of 1:1 or 2:1 and the sub-surface flow was accomplished at a depth of 1m. The sealing included the construction of a sub-base layer consisting of clay material and sand layer each 5cm in depth, as well as the installation of a geomembrane and geotextile – geogrid on top of it.

In the accounted study the exact locations of the construction works were identified while the current situation was analyzed, investigating the state of the natural and human environment. At the same time significant information was offered with respect to the feasibility of the works along with their analytical description.
 
Finally, the extent and size of the caused environmental annoyance from the construction and operation of the works was described, while appropriate methods to treat environmental impacts during construction and operation phase were provided.

BENEFIT
The projects was submitted to the public agencies responsible for the approval the proposed project location and the environmental impact assessment study. The construction of the aforementioned project offered efficient solution to the problem of wastewater management in the Community of Pethelino, Municipality of Strimona, within the Prefecture of Serres.