Modeling of mortality rate of heterotrophic bacteria due to chromium in waste stabilization pond

Bacteria play an important role in oxidation and stabilization of organic and inorganic matter in wastewater treatment plant. This paper presents the development of mathematical model to study the effect of chromium on heterotrophic bacteria in waste stabilization pond. The governing equation of the model is based on the Haldane equation. The model developed reflects the mortality rate of heterotrophic bacteria at variable pH and concentration of chromium. To verify the computed results a series of laboratory experiments has been carried out, the predicted mortality rate was obtained from these models and compared with experimental data. The correlation coefficient R2 was 0.87

Modeling Of Oil Spill Trajectory and Fate in Sudanese Red Sea Coastal Water

Prediction and simulation of the trajectory and weathering of marine oil spills are essential to the development of pollution response and contingency plans, and the evaluation of environmental impact assessments. In this study, SL Ross Trajectory and fate modeling was applied to identify the shortest time for oil to reach Bashayer Red Sea shoreline in order to model the worst case scenarios. Four different scenarios were tested out, two for winter and two for summer. Results showed that in winter the spill movement is towards south and southwest while it moves to the northwest in summer. In both cases the spill will contact Bashayer Marine Terminal (BMT) shoreline within 4 hours in winter and 6 hours in summer rely on the combined effect of wind and tidal current. It was also shown that between 47.7 to 64% of the oil remain on the surface after 10 hours of spil

Effect of Chromium on the Survival of Heterotrophic Bacteria in Waste Stabilization Ponds

Based on experimental work, the effect of pH on heterotrophic bacteria enumeration was studied in batch cultures tests conducted under different chromium concentrations. Samples were collected from the effluent of the primary facultative pond of the University of Dar es Salam (Tanzania) waste stabilization ponds system. The enumeration of heterotrophic bacteria was investigated at different pH values. The density of bacteria was higher at pH 7 than any other pH values for all concentrations. At this pH, the number varied between 1,450,000 to 280,000 at 12 and 108 hours after addition of 5 mg/l chromium concentration. In case of 50 mg/l and pH 7 the number reduced dramatically to 98 to 0 at 12 and 108 hours respectively. It was observed that, the pH of 11 was significantly detrimental to the heterotrophic bacteria. The number ranged between 4000 to 500 in case of 5 mg/l after 12 and 108 hours. Only 13 heterotrophic bacteria were counted after 12 hours when 50 mg/l of chromium concentration was added

Petroleum Hydrocarbons Pollution o n the Sudanese Red Sea Coastal Water

The aim of this paper is to determine the extent of petroleum hydrocarbons pollution on the Sudanese Red Sea coast (Portsudan harbor and Bashayer Marine Terminal (BMT)), to achieve this goal laboratory work was conducted to determine hydrocarbons concentration. The highest concentration of Total Petroleum Hydrocarbons (TPH) in seawater was found at strip I (dockyard) with the average of 80.2 mg/l, the next to the highest concentration was generally occurred at strip IV (BMT), the ranges of concentrations were between 5.8 and 24.2 mg/l with mean value of 14.98 mg/l. Values of oil concentration at strip II (South port) are much lower than those of strip I (6.8 to 10 mg/l). Higher concentrations, ranging from nil to1320 mg/kg were detected in the sediment samples. It can be concluded on this basis that most of the Portsudan harbor and BMT suffers from oil pollution in different degrees according to UNEP and AIDMO. No oil contamination was observed at strip III (North port). The GC measurements proved those hydrocarbons contaminations were due to biologic and petrogenic origins, most oil samples light and middle fractions

Assessing the Spreading of Nile Blend Crude Oil in the Sudanese Red

Spreading is one of the most important processes of the early stages of oil slick transformation. Four physical forces were considered to develop spreading: gravity, inertia, viscous and surface tension forces. In this study Fay’s analytical approach was used to predict the spreading of Sudanese Nile Blend in the Red Sea coastal water. These results were verified using experimentally determined data from the measurement of the spread of Sudanese crude oil and kerosene on the surface seawater of the Red Sea. Two different weather conditions (wind and calm weather) were considered. The spread under calm condition was found to be slower than that under wave action. Field data showed that Fay's theory greatly underestimates slick growth. The spreading rate of kerosene is found to be 1.12 to 4.78 times the spreading rate of NB crude oil. The results of NB was compared with other three crude oils namely Arabic Light crude oil, North Sea crude oil, and Venezuela crude oil using Fay spreading theory. The results show that spreading rate of Arabic light, North Sea and Nile Blend are all most the same. Venezuela crude oil showed a lower spreading rate. Keywords: Spreading, Fay equation

معالجة مياه الشرب باستخدام الطاقة الشمسية

Sudan has the blessing of the sun shining; we can take advantage of this renewable energy to design drinking water treatment systems, especially Sudan suffers from contamination of drinking water. In this study, the design of device made of available local materials and uses solar energy for water treatment has constructed. Samples of water were collected and analyzed before and after treatment and then the results compared to the Sudanese drinking water standards to ensure conformity of the treated water to bacteriological, physical and chemical specifications. We found that the treatment completely got rid of pathogenic bacteria and improved the physical and chemical properties of water