Prediction of biodegradability ratios in wastewater treatment plant of Skhirat Morocco
Abstract
In this note, our study was carried out by physico-chemical monitoring in terms of organic matter. The mean objective is to evaluate the performance of the Skhirat wastewater treatment plant based on the ratios COD/BOD and BOD/COD in order to know the degree of biodegradability and to make the decision about the treatment model to choose. In fact, the performances acquired in terms of COD and BOD are respectively of the order of 87.26% and 88.35%; what is significant downstream of this station that we take advantage of to irrigate several green spaces by saving all conventional water resources. In addition, the organic material is easily biodegradable with ratios of COD/BOD and BOD/COD respectively of about 2.05 and 0.49. This allows us to adopt an appropriate biological treatment by design and sizing suitable structures.
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Introduction
At these last decades, Morocco has experienced a very significant development in the installation of the stations of purifications in several communes of the country. Because of development of the populations socio-economically the polluting load by equivalent-inhabitant has increased as rejection of domestic and industrial wastewaters to the network of collective cleansing arriving at the sewage treatment plant of the town of Skhirat located in the area Rabat-Sale-Kenitra.
Obviously, the composition of wastewaters reflects the life styles [1]. Pollution is an artificial phenomenon resulting either from the natural substance concentration or of the no natural synthetic compounds (xenobiotic) rejected into the environment [2].
The organic and inorganic substances rejected into the environment following domestic, agricultural and industrial activities of water lead to an organic and inorganic pollution [3,4]. At the horizon, these effluents pose a future problem because of the increase in the population which will generate very large quantities of pollutants what requires an appropriate treatment by correcting any specific anomaly. The objective of this study is of knowing the degree of biodegradability for the decision making of which type of treatment to follow, while being based on the ratios of COD/BOD and BOD/COD.
Conclusion
According to the hall above results, we can deduct a ratio from COD/BOD of monthly mean value of about 2.92 which is greater than 2 but less than 3 what mean that these effluents are of domestic predominance with easily biodegradable organic matters.
This result is confirmed by the report of BOD/COD which is about 0.48. So these ratios help us to make a good decision to carry out a biological treatment what is in conformity with the actual sewage treatment plant of biological lagoon type at the of the town of Skhirat.
