The Central Development Region (CDR) of the Republic of Moldova includes 13 administrative districts,14 cities and 340 villages (communes). The largest city in the region is Ungheni, with a population of 38,100 inhabitants, Orhei - 33,500 inhabitants and Straseni - 21,200 inhabitants.
In the Central Development Region, are evacuated about 6 million m3 of wastewate. The maximum volume of waste water discharged is attested in the districts of Orhei (1.1 million m3), Ungheni (800 thousand m3) and Ialoveni (566 thousand m3). Out of the total volume of waste water, about 37% were discharged without treatment and 3.8 million m3 (63%) were insufficiently treated.
Both the purified wastewater and the non-treated wastewater once reached the natural environment have a major impact on it, due to the presence of a varied load of pollutants, so it is important to know which categories of pollutants reach the environment once the discharge of these waters, in order to be able to determine later on how they affect the environment. The highest load of pollutants is in the waste water discharged from the urban area of the region, due to the concentration of industrial enterprises in this area but also to better monitoring of these discharges, compared to the rural area due to the lack of sanitation networks in most localities. The main quality indicators analyzed are: biochemical oxygen demand, fixed residue, chlorides, nitrogen compounds, suspended solids, sulfates, fats and detergents, these being present in the wastewater discharged in most districts of the study region
The main problems related to wastewater are associated with: (1) the toxicity of the pollutants, due to the chemical and biological content, (2) the difficulty of finding the right instrument for the characterization and monitoring of the pollutants caused by the complexity of these waters, and (3) the identification of the appropriate method for effluent detoxification.