SONOCHEMICAL SOLUBILIZATION OF NITROGEN AND PHOSPHORUS: IMPROVEMENT OF THE EFFICIENCY

摘要

Dairy wastewater is an environmental problem due to its volume and organic contents. The treatment of non-biodegradable organic matter in dairy wastewater occurs with great difficulties. The application of ultrasonic wave irradiation converts nutrients from solid to soluble phase, which can facilitate their degradation by microorganisms. Ultrasonic wave irradiation could ameliorate the nutrient balance (N/P ratio). Samples of Tehran Pegah Dairy Complex were chosen for treatment and selected powers and exposure times were 300, 600, 900 W and 60, 120, 240 and 480 s, respectively. Samples, after being subjected to ultrasonication, were analyzed for TKN, TP, pH and temperature. Operating frequency of the apparatus was 20 kHz. After the analysis, the following increases were noted: for "TKN solution" at 300 W and 480 s: 81.10% (maximum); for "TP solution" at 900 W and 60 s: 49.97% (maximum); for pH range at 600 W and 60 s: 7.1 to 7.47; for temperature at 900 W and 480 s: 150% (maximum). After ultrasonic treatment, the resistant organic compounds were converted to the soluble phase and became ready for biological treatment. In this phase, as the nutrients are more easily available for the consumption of microorganisms, the possibility of increasing the efficiency is provided. Hence, ultrasonication method has the capacity to be used as a "pretreatment" for the biological treatment.