Evaluation of the fate of contaminants in the municipal waste water treatment plant of Pitesti, Romania

Project Name, Project Country
Evaluation of the fate of contaminants in the municipal waste water treatment plant of Pitesti, Romania.

Summary of Project  Activities Implemented
The waste water treatment plant (WWTP) of Pitesti is located on the right side of Arges River and had, in 2006, an average flow rate of influent 45’000 m3/day of which approximately 50% are municipal wastewater and 50% contain industrial wastewater.
Pitesti WWTP monitoring was performed by analyzing the 24 hours composite sample collected monthly in the period March-November 2007. Effluent was sampled every two hours – for 24 hours (once a month) and mixed as a composite sample. In addition, such effluents samples were taken each day during a one week sampling campaign. The waste water discharges of five different companies into municipal sewage collector was also monitored. All samples were analysed to determine their physical-chemical properties. The heavy metal concentrations in the waste water and in the effluent were mostly low and did not exceed statutory values. Only the concentration of cadmium and zinc in sewage sludge partly exceeded legal limit values. Detectable concentrations of trichloroethylene, trichlorbenzene, carbontetrachlorid and tetrachlorethylene were found in the industrial discharge. We found increased concentrations of nitrogen and phosphorus compounds in the effluent, which is discharged in the Arges river.
The material flow analysis showed a daily inflow for phosphorus of 397kg in the waste water resulting in 1.6g phosphorus per day and connected inhabitant.

Goal
In this study we aimed to achieve a characterisation of the waste water and the cleaning performance of the WWTP of Pitesti and to apply the material flow analysis.

Results Expected vs. Results Achieved by Swiss Technical University and by Partner
Generally the inflow concentrations of nutrients were comparable to values of typical waste water in Switzerland, however, the actual WWTP has a low nutrient removal capacity. Large quantities of nitrogen and phosphorus compounds are discharged in Arges river along with the effluent, with major importance for the initiation of the eutrophization phenomenon. In this study we only found slightly increased heavy metal concentrations in sludge and traces of toxic organic compounds in the industrial discharges for municipal waste water.

Validation of Results by Swiss Technical University and by Partner
The cooperation between the Swiss and Romanian Partner worked very well, two Swiss students accomplished their diploma thesis working on this project. To perform a material flow analysis it was often difficult to collect reliable data from the city of Pitesti. The storage of chemical samples was often done by room temperature, which is critical for some of the monitored parameters.

Sustainability / Outlook
As industrial activity and their production are expected to grow the separate treatment of industrial waste water and the monitoring of problematic substances in the waste water should be more emphasized in future. The applied material flow analysis will be an important tool to optimize the processes in the WWTP of Pitesti and in other WWTPs of Romania. Quality management for sample campaigns will be important in the future.

Project Duration
Novembre 2006 – February 2008

Contact
Dr. Rolf Krebs, Zurich University of Applied Sciences, Grüental, CH-8820 Wädenswil; rolf.krebs@zhaw.ch, Tel. 058 934 57 90