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2. Hydrodynamic and dispersion studies in an estuary physical model incorporated with an idealized groundwater

Author

Tedjakusuma, Teddy

Abstract

A study on hydrodynamic and dispersion has been undertaken in an estuary physical model. The model represented the Severn Estuary in the UK which has the second largest tidal range in the world. The scale of the model was 1:125 vertically and 1:25,000 horizontally. Experiments in nine sample points showed that water level was different in those points. Velocity measurements showed that the velocity in the physical model coild be analysed using the wave resonance theory. The velocity profile measurements showed that the balance between ebb and flood tide, and this balance were different in different sampling points. The experiments were then compared to the computer modelling results. The water level model showed accordance with the experimental results. The velocity model results were then calibrated using several parameters, namely n-Manning, COED, and momentum correctioncoefficient (β). The calibration was then continued by the refinement of boundary condition and bathymetry. Studies on dispersion in the estuary physical model revealed that longitudinal dispersion coefficient affected the dispersion significantly, while the lateral turbulent diffusion affected the dispersion less significantly. Constant dispersion coefficient was compared with the variable dispersion coefficient, and the results showed that the constant dispersion coefficient gave a better representation of the dispersion process. Studies were also undertaken in an idealized groundwater which was linked to the estuary physical model. The static and dynamic conditions of the groundwater were studied. For static condition which was also undertaken to calibrate the water level probes, the change of water level in the groundwater clearly followed the changes in the estuary water levels, with a delay of water level according to the distance between the borehole and the estuary boundary. Dynamic condition of the groundwater as a results of tide in the estuary clearly shows the phase difference and the tide range at each borehole according to their distance to the estuary boundary. The effect between pump and tide was studied, and this showed clearly the effects of each component on groundwater level. Through Darcy’s analysis it was proved that the groundwater hydrodynamics follow the Darcy’s principle. Finally the dispersion in the groundwater were studied using two scenarios, namely open-open boundary and close-open boundary. Analysis results showed that open-open boundary gave lower dispersion coefficient than the close-open boundary.

Published
2018

5. Microplastics abundance in domestic wastewater as a pollutant source for the Daroy River, Indonesia.

Author

Fauzi, Mhd., Soewondo, Prayatni, Darnas, Yeggi, Handajani, Marisa, Tedjakusuma, Teddy, Nizar, Muhammad, Muna, Cut R., and Nur, Ansiha

Subjects
SEWAGE, PLASTIC marine debris, MICROPLASTICS, POLLUTANTS, WASTEWATER treatment, MICROSCOPES
Abstract

Domestic wastewater in Gampong Garot, Aceh Besar Regency, Aceh Province, Indonesia is directly discharged to the Daroy River without any treatment process. Domestic wastewater from Gampong Garot has been one of the contributors to microplastics contamination in the Daroy River. The microplastics (MPs) contained in domestic wastewater might come from used soaps and detergent products, as well as the scouring of clothes during washing. Thus, this study aims to investigate the abundance of MPs in domestic wastewater in Gampong Garot. The sampling points were determined based on purposive sampling, with samples taken at the end of the main pipe that directly leads to the Daroy River. Organics in domestic wastewater were removed using 30% H2O2 liquid through a digestion process at a temperature of 75°C. MPs characteristics such as size, shape, and colour were visually analysed using a light binocular microscope at 100x magnification, while the polymer type was analysed using Fourier transform infrared (FTIR) analysis. The concentration of MPs in domestic wastewater in Gampong Garot was 30.238 ±1.228 particles·(100 cm)-3 sample. The most common sizes of MPs were found to be in the range of 1,001-5,000 µm, while the dominant colour and shape were transparent and fibre-like. Polyester (PES) was the most detected type of MPs. These findings highlight the need for wastewater treatment before discharge into aquatic bodies. [ABSTRACT FROM AUTHOR]

Published
2023
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6. Initial study of the Coix lachryma-jobi application in reducing algal growth in eutrophic lake

Author

Iqbal Rofiq, Tedjakusuma Teddy, and Dwinandha Dhimas

Subjects
Environmental sciences, GE1-350
Abstract

The usage of Hordeum vulgare or barley straw as an algistatic to control eutrophication in lake has been applied in the United States and England. Inspired by barley straw, this research studied about Coix lachryma-jobi as a substitute for barley straw in Indonesia. The aim of this research is to determine the applicability of Coix lachryma-jobi product in reducing algal growth along with its interactions with the nutrients in the water. Two stages of experiment were conducted. The first stage was applying three different products of Coix lachryma-jobi (powder, chop, and straw) in the reactors filled with water from Domestic Wastewater Treatment Plant as a representation of hypertrophic water body. Then the chlorophyll concentration was monitored to indicate algal growth. Another experiment was applying Coix lachryma-jobi in the reactor filled with tap water and water sample. The result of the experiments show that the straw of Coix lachryma-jobi without further physical treatment is the most effective to reduce algae population in the water. However, the mechanism of the algal growth has not been affected by the interactions between Coix lachryma-jobi and the nutrients.

Published
2020
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7. Hydrodynamic and dispersion studies in an estuary physical model incorporated with an idealized groundwater

Author

Tedjakusuma, Teddy

Subjects
Physics::Geophysics
Abstract

A study on hydrodynamic and dispersion has been undertaken in an estuary physical model.\ud The model represented the Severn Estuary in the UK which has the second largest tidal range\ud in the world. The scale of the model was 1:125 vertically and 1:25,000 horizontally.\ud Experiments in nine sample points showed that water level was different in those points.\ud Velocity measurements showed that the velocity in the physical model coild be analysed using\ud the wave resonance theory. The velocity profile measurements showed that the balance\ud between ebb and flood tide, and this balance were different in different sampling points. The\ud experiments were then compared to the computer modelling results. The water level model\ud showed accordance with the experimental results. The velocity model results were then\ud calibrated using several parameters, namely n-Manning, COED, and momentum\ud correctioncoefficient (β). The calibration was then continued by the refinement of boundary\ud condition and bathymetry. Studies on dispersion in the estuary physical model revealed that\ud longitudinal dispersion coefficient affected the dispersion significantly, while the lateral\ud turbulent diffusion affected the dispersion less significantly.Constant dispersion coefficient\ud was compared with the variable dispersion coefficient, and the results showed that the\ud constant dispersion coefficient gave a better representation of the dispersion process. Studies\ud were also undertaken in an idealized groundwater which was linked to the estuary physical\ud model. The static and dynamic conditions of the groundwater were studied. For static\ud condition which was also undertaken to calibrate the water level probes, the change of water\ud level in the groundwater clearly followed the changes in the estuary water levels, with a delay\ud of water level according to the distance between the borehole and the estuary boundary.\ud Dynamic condition of the groundwater as a results of tide in the estuary clearly shows the\ud phase difference and the tide range at each borehole according to their distance to the estuary\ud boundary. The effect between pump and tide was studied, and this showed clearly the effects\ud of each component on groundwater level. Through Darcy’s analysis it was proved that the\ud groundwater hydrodynamics follow the Darcy’s principle. Finally the dispersion in the\ud groundwater were studied using two scenarios, namely open-open boundary and close-open\ud boundary. Analysis results showed that open-open boundary gave lower dispersion\ud coefficient than the close-open boundary.

8. Hydrodynamic and dispersion studies in an estuary physical model incorporated with an idealized groundwater

Author

Tedjakusuma, Teddy and Tedjakusuma, Teddy

Abstract

A study on hydrodynamic and dispersion has been undertaken in an estuary physical model. The model represented the Severn Estuary in the UK which has the second largest tidal range in the world. The scale of the model was 1:125 vertically and 1:25,000 horizontally. Experiments in nine sample points showed that water level was different in those points. Velocity measurements showed that the velocity in the physical model coild be analysed using the wave resonance theory. The velocity profile measurements showed that the balance between ebb and flood tide, and this balance were different in different sampling points. The experiments were then compared to the computer modelling results. The water level model showed accordance with the experimental results. The velocity model results were then calibrated using several parameters, namely n-Manning, COED, and momentum correctioncoefficient (β). The calibration was then continued by the refinement of boundary condition and bathymetry. Studies on dispersion in the estuary physical model revealed that longitudinal dispersion coefficient affected the dispersion significantly, while the lateral turbulent diffusion affected the dispersion less significantly.Constant dispersion coefficient was compared with the variable dispersion coefficient, and the results showed that the constant dispersion coefficient gave a better representation of the dispersion process. Studies were also undertaken in an idealized groundwater which was linked to the estuary physical model. The static and dynamic conditions of the groundwater were studied. For static condition which was also undertaken to calibrate the water level probes, the change of water level in the groundwater clearly followed the changes in the estuary water levels, with a delay of water level according to the distance between the borehole and the estuary boundary. Dynamic condition of the groundwater as a results of tide in the estuary clearly shows the phase difference and the ti

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