Removal of nitrate from the effluent of Tripoli water treatment plant using the ion exchange process

Abstract

The objective of this research is to examine the water quality of Tripoli Water Treatment Plant (WTP) and study its upgrade for the removal of nitrate pollutant. The plant is divided into two parts: the old and the new one. Both have the same treatment processes. The project is divided into three main sections: 1) testing the water quality at Tripoli water treatment plant, 2) ion exchange experiments for the removal of nitrate from the effluent of the treatment plant, and 3) upgrading the design of the plant by integrating the proposed ion exchange to its main processes. Many samples were collected from each process of the WTP for a period of two months; the results obtained from physical, chemical and biological analysis of raw and treated water of the plant are polluted with nitrate, nitrite and bromide even after treatment. Since nitrate is an acute contaminant, the reliability of the treatment system is an utmost concern. Therefore, laboratory investigations were conducted to reduce nitrate loads found in the effluent of the WTP as the second section of this study. Many trials and experiments were implemented and used to achieve the best outcomes. They showed that the ion exchange method is effective for the removal of nitrate in addition to nitrite and bromide. After the first round of the treated water through resins, the level of nitrate decreased directly under the standards (10 mg/l) and after the third round it reached traces in addition to the decrease level of nitrite and bromide. Furthermore, a special prototype system was designed for this purpose, 19 batches were made with different passes and rounds in order to get the most accurate results. But unfortunately, the results could not be obtained due to a sudden problem occurred with the Ion Chromatography equipment that analyze these pollutants. In order to complete the project, the conceptual design of the ion exchange was studied based on the land availability on the site. This was the last part of the study.