Numerical Study of Water Quality Improvement in a Port Through a Forced Mixing System

Abstract

Over the years, the growing development of coastal areas urbanization has led to marine habitat loss and degradation. With the continuous increase in population and industrialization, coastal zones are facing several issues arising from the continued decline in the quality of water and sediments and the rapid deterioration of marine ecosystems. Shipping activities exacerbate such a situation, especially in the vicinity of harbors, which are often affected by stagnant and contaminated waters, containing organic as well as inorganic substances. In Italy, although the environmental legislation does not appropriately consider the port as a water body, specific actions are required in order to properly manage these basins. In this regard, a 3D numerical model is firstly performed to detect the hydrodynamic circulation and the water renewal within a port in the southern Adriatic coast of the Apulian region (South of Italy). Then, some configurations of a possible technical solution, i.e. a pumping system aimed at improving water quality, are modelled. Specifically, the system consists of a pump that draws water from areas with less water exchange and enters it into areas inside the port with lower hydrodynamic circulation. The different results, in terms of (i) number of sinks and sources, and (ii) their location, are compared to obtain the best technical solution that enhances the water renewal and then improves its quality. The study allows readers to identify methods for proper planning and management of such shallow sea areas with low water exchange and thus highly susceptible to accumulation of harmful substances in the water, that are ports.

Modeling of Hydrodynamics and Dilution in Coastal Waters

“…The quality of water near the coast is an outcome of the net result of any treatment, inactivation, and dilution of discharged waste [6]. To understand the complex and vital phenomena of the mixing process, numerical, analytical, physical models, and field experiments can be used [7][8][9][10]. The integration of this knowledge with different methodologies can deal with the complexity of hydrodynamic and hydraulic studies.…”

Computational simulation of round thermal jets in an ambient cross flow using a large-scale hydrodynamic model

“…It is a professional engineering software package for three-dimensional free-surface flows, designed in a modular structure and applicable to simulations of hydraulics, water quality and sediment transport in water bodies (DHI Software, 2009). The suitability of this model has been tested in previous studies considering the planning of brine outfalls from desalination plants (Malcangio and Petrillo, 2010) and forced mixing systems in ports (Malcangio et al, 2017), both providing good results in the large-scale domain. This current study required the application of the hydrodynamic module (HD), which solves the continuity and momentum equations in three dimensions, applying the so-called RANS equations in a Cartesian coordinate system (x, y, z) Software, 2009).…”

“…The numerical simulations are performed with the hydrodynamic model MIKE 3 (by DHI), which has been utilized previously for hindcasting and forecasting of various hydro-physical (e.g. hydrodynamic, water quality and sediment transport) modelling scenarios in natural water bodies and verified extensively by in situ measurements (Pietrzak et al, 2002;Lumborg, 2005;Lessin and Raudsepp, 2006;Malcangio and Petrillo, 2010;Mali et al, 2018;Malcangio et al, 2017). The novelty of the present work is in applying this large-scale model to predict both the near-and far-field hydrodynamic processes of turbulent jets in a cross-flowing ambient fluid body.…”

Laboratory Investigation on the Evolution of a Sandy Beach Nourishment Protected by a Mixed Soft–Hard System

“…They dissipate the incident wave energy, hence reducing the wave hydrodynamic action on coasts [11,12] and extending the residence time of sediments in the sheltered region [13,14], depending on configuration parameters (i.e., freeboard, distance from the shoreline, and transmission coefficient), wave climate and nearshore seabed [15][16][17][18]. Moreover, they have a lower impact on both hydrodynamic processes and nearshore zone morphodynamics with respect to the emerged detached breakwaters and groins, since they are able to enhance the water circulation, its renovations rates [19,20] and biological biodiversity [21].…”