Monitoring quality of water intended for human consumption in Romania; Determination of NOM fractions and BDOC
An investigation has been performed to monitor the raw and drinking water quality in the Romanian counties Calarasi and Braila in the south-east of Romania. As a part of this investigation, fractioning of the natural organic matter (NOM) and determination of the regrowth potential as biodegradable organic matter (BDOC) has been performed.
The plants treating raw water from the river Danube had a DOC in raw and treated water of 3.4–4.1 mg C/L and 2.0–2.7 mg C/L, respectively. The DOC content in the different NOM fractions VHA, SHA, CHA and NEU in the raw water was 1.2–1.9 mg C/L, 0.3–0.6 mg C/L, 0.2–0.7 mg C/L and 0.3–1.0 mg C/L, respectively. The raw water colour was approximately 10 mg Pt/L, and was reduced to ≤3 mg Pt/L during treatment. The measurements of the NOM fractions and the BDOC during treatment showed that coagulation removes parts of the very hydrophobic NOM, minor parts of the other NOM and a great part of the BDOC, while the chlorination through oxidation increased the BDOC. The overall effect of the treatment on the BDOC, which means on the regrowth potential, was negligible.
The groundwater had BDOC levels of 0.0–0.3 mg C/L, which increased to 0.4–0.9 mg C/L in treated water, because of the rather high chlorine dosages applied.