Good Industry Practices: A Municipal Wastewater treatment plant in Athens, Greece


Brief introduction to the problem - summary
The main municipal wastewater treatment facility of Athens started operating during the 1980s. As of the mid 90’s several revamping phases were implemented in order to upgrade the facility in terms of operation and environmental compliance. The plant emitted a significant amount of odours which were considered an issue till the mid 2000’s, but several investments for deodorizing and better treatment of the WWT feed led to the minimization of the problem.

Problem description

What is the plant(s) type, size, location, technical characteristics?
Municipal WWT South West of Athens accepts more than 700k m3 per day of sewage.
What was the problem? How many citizens were affected and for how long?
There were intense odour incidents that affected a quarter of Athens city population seasonally for almost two decades.

Reporting phase

How was the problem raised? How were complaints reported?
The problem was reported by the local press and protests were staged near the area of the facilities.

Monitoring phase

Was the problem monitored? If yes, how? Which techniques/ methods were applied? No information available.

What was the result of the monitoring phase? No information available.

Evaluation phase

How was the data analyzed? How could the collected data be accessed? No data available publicly.

What was the outcome of the data analysis? No data available publicly.

Resolution phase

How was the problem solved? Which technology was applied?

  • Pre-treatment process with removal of heavy solids, gridding, removal of sand and deodorizing.
  • The pretreated sewage was transferred with submerged pipelines in the facility.
  • Primary sedimentation tanks collected the primary sludge.
  • Advanced secondary biological treatment with activated sludge system achieved removal of organic load and a significant reduction of nitrogen.
  • Digestion, dehydration and thermal drying of sludge were implemented as additional stages in the treatment of wastewater.
  • The processed outflow of WWTP was diffused through pipelines.

Who/ How were the different stakeholders involved in the solution of the problem?
A consortium of private companies and the Water Supply and Sewerage company, which is publicly owned.

How much did it cost? Who paid for it? How long did it take?
The revamping lasted about 3 years.

Verification phase

Did the solution work? Was the impact reduced?
The solution worked and the impact was reduced with no reported incidents throughout the year.

How was the effectiveness of the applied solution monitored?
The company running the facility monitored and reported a series of parameters measuring the solution process and its environmental outcome, to ensure that the odour requirements were covered.

Communication phase

What happened after that? Several newsletters were published.

Was the public properly informed about the end of the process? Yes, through the portal of the managing company.
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