3D Numerical Modeling of Dispersion Potential of Sewage Sludge at the Proposed Submerged Site off the Coast of Son-Tra Peninsula, Danang City

Assessment of potential risk of sludge dispersion of Tho-Quang fishing port is essential to ensure compliance with the Technical Regulations on assessment of dredges and identification of dredged sludge areas in Circular No. 28/2019/TT-BTNMT dated December 31, 2019 of the Ministry of Natural Resources and Environment. However, there are still many discussion regarding the possibility of spreading waste after submerging in the proposed area and potentially affecting the natural ecosystem of the vicinity off the coast of Son-Tra peninsula. The results of this study will contribute to the scientific theoretical basis to be able to quantitatively evaluate the spread of sewage sludge extracted from the dredging of Tho-Quang boat lock. In this study, we will apply 3D numerical modeling to simulate dredged sludge waste propagation with different discharge scenarios in terms of submergence depth, submerged sludge discharge as well as other hydro-meteorological scenarios in order to evaluate the potential risks of sewage sludge spreading to the nature reserve in the Son-Tra peninsula, Danang city. The results show that the influence of tidal current plays a very important role in the spread of sludge. Under the effect of tidal currents, submerged sludge can spread up to 10 km from the discharge center with a concentration of 5 mg/l.