A study of dissolved air flotation tank design variables and separation zone performance

PhD ThesisA study of velocity and turbidity distributions in the separation zone of dissolved air flotation (DAF) tanks was carried out at Franldey and Trimpley Water Treatment Works of Severn Trent Water. Sampling of velocity was made using an Acoustic Doppler Velocimeter (ADV). The instrument is capable of measuring velocities as low as 1 mmlsec and producing three dimensional velocity data. Sixty-four points set at equal intervals within the tank were monitored and the flow rate corresponding to the velocity for each point was recorded. The same points were used for the sampling of turbidity within the tank and the corresponding flow rate for each sampling point was also recorded. The aim of the study was to establish the relative importance of tank design parameters within the separation zone. The ADV probe was found suitable to be used in the investigation based on the data quality obtained. The study indicated that there are some differences in the flow patterns compared to Computational Fluid Dynamics (CFD) models found in the literature. The plan view contour plots indicated that velocities in the x, y and z directions at a quarter depth from the surface of the tank were unstable with irregular velocity patterns. However the CFD models indicated that the flow at this depth was uniform. Also at this depth the vertical velocity was predominantly downward which suggested that the solid liquid separation process is inefficient. Tank physical parameters were found to have a highly significant effect on the velocity distribution using analysis of variance (ANOVA) and analysis of covariance (ANCOVA). These analyses involved higher order interactions and independent predictor variables. The results from the higher order models are difficult to interpret. Thus simple second-order empirical models were used. Empirical models were developed using regression analyses to describe the observed velocity within the tank. These models are appropriate for design purposes. Although the models are not precise, the standard statistical techniques used for data analyses are found to be useful to compare, analyse and develop the appropriate model from the velocity data obtained during the investigation. In terms of turbidity removal, there was no significant difference in the average turbidity readings between different depths of the tank. Comparison of turbidity at different lengths of the tank indicated that the average turbidity readings were identical between three quarter length of the tank from the baffle and at the extreme end of the tank. The results confirm that there were not enough air bubbles within the separation zone for turbidity removal. The size of tank at Franidey can also be reduced by 15% so that the difference between the average flow rate and the surface area between the tank at Frankley and Trimpley is the same. It is expected that the reduction in size will not affect the turbidity within the separation zone due to non significant turbidity removal within this zone.Severn Trent Wate

Development of sprayer nozzle of The unpacked saturator for dissolved air flotation process.

Dissolved air flotation (DAF) process becomes prominent in water treatment technology all over the world. This process had been well-accepted as an alternative for sedimentation due to its potential to remove very small or light particles in a shorter period, simplicity of the design and only required less area. Proses pengapungan udara terlarut semakin meluas dalam aspek rawatan air di seluruh negara. Proses ini semakin diterima dengan baik sebagai satu altematif kepada proses pemendapan kerana potensinya dalam menyingkirkan partikel-partikel yang keeil serta ringan, rekabentuknya yang ringkas dan hanya memerlukan kawasan yang kecil

A Study On The Perfomance Of Sedimentation Tank At The Sungai Kampar Water Treatmeny Plant.

This paper discusses the performance of soIid-liquid separation pfocess at the Sg Kampar Water Treatment works

Automated rescuing boat tracking system using raspberry pi

During floods, safety boats will be dispatched to help flood victims. The location tracking system is important to ensure the safety of the victim. Therefore, this project is conducted to track live locations and monitor flood survivors wirelessly. In tracking the victim’s location, a small and compact computer, called a Raspberry Piis installed on the boat and the recorded data has been uploaded online. This will help firefighters to monitor the location of the boat easily and help the victims navigate the boat to a safe place. A safety camera is installed to help firefighters monitor the situation as well. For system validation, various tests are conducted on-road, swimming pool and Panchor river in Muar, Johor, Malaysia. Hence, the performance on road is accurate. In fact, the recorded speed reading is similar to the speed measured by Google Maps. At the Pagoh Higher Education Hub (HPTP), Johor, Malaysia swimming pool, it is observed that, the faster the boat speed, the shorter the time required to complete a 50 meters trip. Finally, the river testing has shown that the boat speed increases when the boat moves in the same direction as the water current and slows down if the boat and river currents move in opposite directions

OPERATIONAL PERFORMANCE OF VERTICAL UPFLOW ROUGHING FILTER FOR PRE-TREATMENT OF LEACHATE USING LIMESTONE FILTER MEDIA

This study was conducted to investigate the removal of COD, BOD, turbidity and colour from leachate using vertical upflow filtration technique. Limestone media with a density of 2554 kg/m³ was crushed and graded in sizes of 48 mm, 812 mm and 12-18 mm. Trial runs were done before the main experiment at an interval of 24 h analysis. Leachate was between pH 7.94 to 8.12 before experiments but increased to pH 8.42 after the filtration process. Maximum headloss at steady flow rate 20mL/min was 0.5 cm. The optimum treatment was achieved with 4–8 mm, 8–12 mm & 12–18 mm media size in combination and removal efficiency was 22 to 81%, 22 to 75%, 32 to 86%, and 36 to 62% for BOD, COD, turbidity and colour, respectively. Vertical upflow roughing filter can be used for pre-treatment of leachate before further treatment

Removal of Iron and Manganese Using Cascade Aerator and Limestone Roughing Filter

Combination between oxidation and filtration can be used for removing iron and manganese from groundwater especially when the concentrations of these metals were high. This study focused on the effectiveness of the cascade aerator and the size of the limestone filter media to remove iron and manganese from groundwater. Water samples used for this study were collected from orphanage home, Rumah Nur Kasih, Taiping. Universiti Sains Malaysia (USM) has provided a tube well of 15 m depth and 150 mm diameter for the orphanage home. However, the water cannot be used for domestic consumption due to high amount of iron and manganese at 6.48 and 1.9 mg/L which exceeded the drinking water standard of 0.3 and 0.1 mg/L respectively. Using laboratory physical model, the study has shown that the removals of iron and manganese have reduce the concentration until 0.17 and 0.2 mg/L respectively. Thus, the results from this study which utilize cascade aerator and limestone roughing filter could be implemented on site for the community to use the ground water for domestic purposes

Removal of Iron and Manganese Using Cascade Aerator and Limestone Roughing Filter

Combination between oxidation and filtration can be used for removing iron and manganese from groundwater especially when the concentrations of these metals were high. This study focused on the effectiveness of the cascade aerator and the size of the limestone filter media to remove iron and manganese from groundwater. Water samples used for this study were collected from orphanage home, Rumah Nur Kasih, Taiping. Universiti Sains Malaysia (USM) has provided a tube well of 15 m depth and 150 mm diameter for the orphanage home. However, the water cannot be used for domestic consumption due to high amount of iron and manganese at 6.48 and 1.9 mg/L which exceeded the drinking water standard of 0.3 and 0.1 mg/L respectively. Using laboratory physical model, the study has shown that the removals of iron and manganese have reduce the concentration until 0.17 and 0.2 mg/L respectively. Thus, the results from this study which utilize cascade aerator and limestone roughing filter could be implemented on site for the community to use the ground water for domestic purposes

Application of Combined Filtration and Coagulation for Semi-aerobic Leachate Treatment

The landfill leachate was taken from the Pulau Burung Landfill Site (PBLS), Malaysia. Filtration by limestone-zeolite (15 : 25) and limestone-GAC (15 : 25) with filtration rate = 0.01 m3 /m2.minute showed that 70% and 85% of colour and 42% and 70% COD were removed, respectively. Maximum colour removal (93% and 92%) and COD removal (56% and 46%) were achieved by the addition of 2000 mg/L PAC and 9000 mg/L alum respectively. Filtration by limestone-zeolite (15 : 25) and limestone-GAC (15 : 25) followed by coagulation at optimum dosage of 800 mg/L PAC, was efficient to reduce colour (98% and 99%) and COD (70% and 86%) respectively. Copyright © 2009, Inderscience Publishers

Performance of Horizontal Flow Roughing Filter Using Limestone Media for the Removal of Turbidity, Suspended Solids, Biochemical Oxygen Demand and Coliform Organisms From Wastewater

This paper examines and evaluates the removals of turbidity, suspended solids, BOD and coliform organisms from wastewater using different sizes of limestone roughing filter. Results indicated that removal efficiencies depended on the size of the filter medium and applied flow rates. Turbidity, suspended solids, BOD and coliform organisms removals were between 75% and 92%, 79% and 88%, 51% and 67% and 67% and 96%, respectively, in a combination of the three filter media with particle sizes between 1.91 mm and 16.28 mm. Removal efficiency was found to increase with slower flow rates. © 2008, Inderscience Publishers