To reduce the environmental, economical, and safety consequences of ship collisions, it is compulsory that hull structures of all oil tankers arrange for double sides and bottoms. It is clear that double hulls lead to an increase of crash-worthiness and mitigate the possibility of severe damage in ships body and oil spill. Recently, various studies have been conducted to improve the efficiency of double hulls with adding some granular materials into the space between the two walls. In the current research, the collision of double hull vessels filled with energy absorbing granular materials will be studied on both micro and macro scales. For this purpose, the compaction behavior of granulates will be studied at first using DEM. Then considering a representative volume element (RVE) and homogenization technique, the mechanical properties of the particles will be identified for the continuum model. At the next step, since the granular material must be modeled by different methods in different sub-domains (DEM and FEM), a bridging or coupling must be established in the domains interface using, for example, the Arlequin method. At the end, the collision problem in double hull vessels will be simulated and the effects of influencing parameters can be investigated. Project partners: Prof. M. Dosta (TUHH)

The presence of high concentrations of ionic contaminants in groundwater reservoirs pose a serious threat to humans and environment. Amongst, selenium (Se) oxyanions have been recorded in groundwater because of mining, petroleum refining, fossil fuel combustion, and irrigation [2]. In accordance, high Se concentration i.e., 2103 μg/L, 800 μg/L, 2700 μg/L and 4475 μg/L have been found in Soan Sakesar Valley, Pakistan; Atacama Desert, Chile; Martin Creek Reservoir, Texas, USA; and Sirmaur district of Himachal Pradesh, India; respectively [3]. Nevertheless, Se is an essential mineral required by human body however it becomes noxious when found in greater concentrations in drinking water supplies. The oral intake of higher Se concentration (>400 μg/day) may cause serious health problems including reproductive anomalies and developmental abnormalities in foetus, hair loss, body pain, muscle damage, liver and kidney failure, cancer, and even death may occur. Therefore, German drinking water ordinance, World Health Organization (WHO) and U.S. Environmental Protection Agency has set Drinking Water Regulation Limit (DWRL) for Se as 10 μg/L, 40 μg/L and 50 μg/L, respectively [4,5]. To meet stringent Se guidelines and ensure public health safety, an efficient and technoeconomic feasible treatment approach is needed. Amongst, adsorption technology utilizing commercial iron-based adsorbents has shown promising performance for removing contaminants including metal oxyanions from a wide range of water matrices. However, eliminating Se from drinking water is challenging owing to its toxicity, solubility and varying oxidation states. It is commonly found in environment as selenate (Se(VI): HSeO4‾, SeO42-), selenite (Se(IV): H2SeO3, HSeO3‾, SeO32-), selenium (Se(0)) and selenide (Se(-II): H2Se, HSe‾) depending on pH and redox conditions [2]. Previous research [6–8] has shown wide applicability of commercially available iron-based adsorbent i.e., granular ferric hydroxide (GFH) for removal of other oxyanions including arsenic, phosphate, vanadium etc. from water. Therefore, it may be hypothesized that GFH may contain potential in eliminating toxic Se oxyanions from drinking water supplies. In addition, release of iron from poorly crystalline GFH structure into the solution particularly at low redox potential, leading to its higher residual content, has been rarely investigated. Therefore, it will be critical to examine the stability of GFH at long term operations along with its effectiveness in remediating targeted contaminants. In accordance, little is known on how Se oxyanions will behave and react with GFH in aqueous environment. It will therefore be worth exploring the mechanistic insights into the fate, mobility, transformation, and removal behavior of Se species under environmentally relevant conditions. In addition to commercial adsorbents, prior research has focused on utilization of iron-based sorbents for Se remediation from drinking water, however, all these studies only discussed in-depth understanding of batch mode operation [9]. Moreover, there always remains a research gap in utilizing adsorbent material in GEH® adsorbent unit for continuous mode Se treatment from drinking water supplies. Therefore, the planned project aims to address these research gaps and provide practical and sustainable solution to drinking water industries when dealing with toxic Se oxyanions.