Application of Mathematical and Experimental Approach in Description of Sedimentation of Powder Fillers in Epoxy Resin

In this paper, sedimentation inhibition attempts were examined using colloidal silica in a mathematical and experimental approach. Experimental results were validated by a two-step verification process. It was demonstrated that application of quantitative metallography and hardness measurements in three different regions of samples allows us to describe the sedimentation process using modified Stokes law. Moreover, proper application of Stokes law allows one to determine the optimal colloidal silica amount, considering characteristics of applied filler (alumina or graphite). The results of mathematical calculations have been confirmed experimentally—the experimental results show good agreement with the calculated data.

Monitoring of Sedimentation on Geosynthetic Bags Installation Area in Banyuurip Mangrove Center, Ujung Pangkah, Gresik, Indonesia

Banyuurip is one of the villages in Ujung Pangkah District which has potential natural resource that is mangrove forests. However, the occurrence of abrasion and conversion of mangrove land has impacted mangrove ecosystem. Rehabilitation efforts by replanting mangroves have been carried out, but they have not been effective in overcoming the current problems. The reduction of mangrove area that led the decreased of mangrove’s function can affect the livelihood of the local community, including fishermen. The installation of geosynthetic bags, which are sand-filled bags arranged on the ground, is done as an alternative solution in Banyuurip Village which functions as coastal protection and a sediment trap. The utilization of geosynthetic material is often used to help the coastal problem, the used of geosynthetic material is rarely carried out in mangrove areas. This study aims to determine the sediment characteristics, sedimentation rates, and sedimentation process based on the relationship between current velocity and sedimentation rate. The result shows that generally the type of sediment fraction in this location is silt (79,12% - 80,12%) and the rest is clay. The current installation of geosynthetic bags can result in the land extension from the trapped sediment behind the structure. In addition, the current velocity conditions and the sediment transport process also affect the sedimentation process that occurs. The average sedimentation rates around the geosynthetic bags installation area ranged from 150.72-305.01 mg.cm-2.day-1. This study may provide a basic information for further development in Banyuurip Mangrove Center and other mangrove conservation area.

The Use of Flat Ceramic Membranes for Purification of the Liquid Fraction of the Digestate from Municipal Waste Biogas Plants

Due to the rising water deficit in agriculture, digestate is increasingly being considered not only as an alternative fertiliser but also as a potential source of water. The use of recycled water for crop irrigation requires that it be treated in such a way that contaminants from the fermented biomass are not returned to the environment. Membrane processes can provide promising results in this regard. This study seeks to achieve membrane filtration using flat ceramic membranes for effective digestate liquid fraction treatment from a municipal waste biogas plant. Membranes of 1, 5, 15, and 50 kDa, and 0.14 and 0.45 µm are examined. The results obtained show that the application of a sedimentation process, as a preliminary step in the purification of the digestate, allows for a significant reduction in the content of contaminants in the solution. By analysing the effectiveness of the liquid fraction of the digestate purification in the sedimentation-membrane filtration process using flat ceramic membranes, it can be stated that all the membranes tested can be applied in the digestate purification. With an increase in the cut-off value, a deterioration in the quality of the digestate can be observed. The use of the sedimentation process before the membrane process not only improves the final quality of the digestate but also reduces the intensity of membrane fouling.

Modeling of the Sedimentation Process in Water

The sedimentation process occurs in water storage containers. In the sedimentation process, it will be observed how fluid flow occurs and how sedimentation occurs in water. The sedimentation is influenced by the density of the water and the velocity of the water in the water reservoir. This study aims to determine how to model a mixture of solid and liquid particles (suspension) in a water storage container by modeling it into a mathematical form, namely by using differential equations. In this case, the factors that affect the sludge concentration distribution will be used as a reference for modeling the Mathematical equations which will then be solved using differential equations.