Yield, eficient and ajust on Calcium Nitrate dosification in waste water plant treatment

Identifier:  TFG:1645

Handle: https://hdl.handle.net/20.500.11797/TFG1645

Authors:  Gonzàlez Castro, Alexandre

Abstract:
Treatment of waste water has become a very important challenge because of the high necessi-ty of this natural resource. In addition, the difficulty of found the water to our consumption, the treatment of wastewater has become a very useful practice. Waste Water Plant Treatment (EDAR, in Spanish) is the infrastructure where the treatment of waste water is done to introduce it again in the envoirment without put pollution in. This treatment can cause the introduction of pollutant. The water that arrives to de EDAR comes from Waste Water Plant Bombing (EBAR, in Spanish). In this structure –EBAR- waste water stays there long time in anaerobic conditions, faciliting the metabolism of sulphate-reductor-bacteria which, in anaerobic conditions, transform de sulphate from hydrogen sulphide to obtain de oxygen to live. Hydrogen sulphur is a toxic gas that can kill a human when it is in high concentration. When this gas is in low concentrations, humans can smell it. However, when it is in high concentra-tions –more than 40ppm- we can’t smell it so, when the concentration of this gas is enough to kill an human, this can’t be detected. To reduce the emission of H2S while de treatment of waste water, a Nutriox® - calcium nitrate 8% solution- dosification has been done in EBAR to avoid the metabolism of sulphate-reductor-bacteria. That occurs because nitrate increases redox potential of the waste water, forcing bacteria to obtain the oxygen from nitrate instead of sulphate, avoiding the H2S formation