Abstracts

 

Water International
Volume 10, Issue 4, 1985, Pages 151-155  

 

Potential of water development in Saudi Arabia.

Farooq, S.Show author details, Al-Layla, R.I.Show author details Correspondence address

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

________________________________________________________

Abstract

Presents the state-of-the-art concerning the development, conservation, and reuse of waters within the Kingdom. The main conventional water resources are non-renewable and renewable groundwater of 3450 million m3, and 1145 million m3, respectively. A conservation committee in Dhahran has been formed to conserve and reuse the water for beneficial purposes. Water quality standards and criteria for water reuse have been developed. The religious implications of the use of treated wastewater have been examined and the use of recycled water after proper treatment has been approved for all religious and mundane purposes. Finally, an outline is given of various ongoing reuse projects in the Kingdom with the objective of obtaining 15% of total water demand through recycling by the year 2000. -from Authors

 

 

 

 

 

 

 

 

 

Water Resources Bulletin
Volume 24, Issue 1, February 1988, Pages 77-85  

NUMERICAL MODELING OF SOLUTE TRANSPORT PATTERNS IN THE DAMMAM AQUIFER.

Al-Layla, RashidShow author details, Yazicigil, HasanShow author details, de Jong, RemyShow author details Correspondence address

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

________________________________________________________

Abstract

During the part two decades, the Kingdom of Saudi Arabia has witnessed rapid development in its agricultural and urban areas, which has resulted in greater reliance being placed on its ground water aquifers. The intensive development, particularly along the coastline and in the absence of adequate replenishment sources, has led to major deterioration in the quality and quantity of ground water resources. A numerical model of the Dammam aquifer in the Eastern Province is developed and used to predict the extent of the saline instruction in the aquifer. The types of stress effecting the solute transport were identified and remedial measures were suggested.

 

 


 

 

 

Arabian Journal for Science and Engineering
Volume 11, Issue 4, October 1986, Pages 363-370  

INFLUENCE OF THE UNSATURATED ZONE ON THE SALT-WATER FRONT IN UNCONFINED AQUIFERS.

Al-Layla, Rashid I.Show author details Correspondence address

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________________________________________________

Abstract

The flux due to artificial or natural recharge, or due to discharge resulting from excessive evaporation originating at the natural groundwater table, must traverse the unsaturated zone above unconfined aquifers. This process affects the existing hydraulic heads in the saturated zone, thereby effecting the overall dynamic behavior of the sea water/fresh water interface. A numerical model was developed to account for the influence of capillary storage and capillary flow in the partially saturated region on the development of the shape of that interface. The model demonstrated that the contribution of the capillary flow is significant when the effective permeable height is the same order of magnitude as the saturated thickness.


 

 

Journal of Water Resources Planning & Management - ASCE
Volume 113, Issue 3, 1987, Pages 392-404  

Farooq, S.., Al-Layla, R.I.Show author details Correspondence address

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

Study of water transportation to Saudi Arabia, Pakistan, Sudan, Egypt and Iraq

_____________________________________________

Abstract

Three regional sources of freshwater around Saudi Arabia are identified: the Indus River in Pakistan, the Nile River in Sudan and Egypt, and the Euphrates and Tigris Rivers in Iraq. Transportation costs are calculated using tanker shuttle service, in which case tankers are used exclusively for the transportation of freshwater between loading and unloading ports. The average water transportation costs from Karachi to Dammam, Port Sudan to Jeddah, and Suez to Jeddah are $0.79, $0.29 and $0.61 m 3 , respectively, in a 300 000-dwt tanker. Reported transportation costs through backhaul service (return cargo) are $1 and $2/m 3 at worldscales of 30 and 60, respectively. These costs compare favorably with desalination costs of $1.54-$4.5/m 3 in Saudi Arabia. Using these unit costs, four scenarios are discussed for transportation of 910 000 m 3 of water/day through different schemes. Water transportation from Pakistan appears to be the most cost-effective. -from ASCE Publications Information

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Water Resources Bulletin
Volume 23, Issue 3, June 1987, Pages 423-434  

 

OPTIMAL MANAGEMENT OF A REGIONAL AQUIFER IN EASTERN SAUDI ARABIA.

Yazicigil, HasanShow author details, Al-Layla, Rashid I.Show author details, de Jong, Remy L.Show author details Correspondence address

King Fahd University of Petroleum &, Minerals, Dhahran, Saudi Arabia, King Fahd Univ of Petroleum & Minerals, Dhahran, Saudi Arabia

________________________________________________________

Abstract

This paper describes the formulation and application of a ground-water hydraulic management model to determine the optimal development and operating policies of a regional aquifer in the Eastern Province of Saudi Arabia. The hydraulic response of the aquifer system is represented by a simulation model that is linked to an optimization management model using response functions. Yearly optimal ground-water extraction rates over a planning horizon of 15 years are determined for four scenarios, each reflecting alternative ground-water development policies. The results are presented in the form of tradeoff curves, relating drawdowns to optimal pumpage.



 

 

 

 

Arabian Journal for Science and Engineering
Volume 11, Issue 4, October 1986, Pages 349-362  

 

NUMERICAL MODELING OF THE DAMMAM AQUIFER IN EASTERN SAUDI ARABIA.

Yazicigil, HasanShow author details, Al-Layla, Rashid I.Show author details, de Jong, Remy L.Show author details Correspondence address

University of Petroleum & Minerals, Dhahran, Saudi Arabia, Univ of Petroleum & Minerals, Dhahran, Saudi Arabia

________________________________________________________

Abstract

During the past two decades the Eastern Province of Saudi Arabia has experienced rapid development of its agricultural and urban areas and of associated industries, with consequent increased reliance on local aquifers to satisfy most of the current and future needs. The Eocene Dammam Formation is one such aquifer and it has experienced rapid declines in groundwater levels in recent years. A numerical groundwater model of the Dammam aquifer was constructed to assess the regional hydraulic properties of the aquifer and to investigate its development potential in the near future. The model results indicated wide variations in transmissivity within the aquifer system, and relatively small contributions by releases from storage and by leakage.


 

 

 

Water International
Volume 14, Issue 1, 1989, Pages 6-12  

Scenario planning for water resources: a Saudi Arabian case study

De Jong, R.L.Show author details, Yazicigil, H.Show author details, Al-Layla, R.I.Show author details Correspondence address

King Fahd University of Petroleum & Minerals

________________________________________________________

Abstract

Uncommonly rapid development of the oil-rich Eastern Province of Saudi Arabia has led to heavy stresses on the local groundwater resources and there has arisen concern for the adequacy of supply to sustain future growth. Whereas oil is the only significant export commodity, the demand for it has an important and immediate impact on water exploitation activities. In this article four development scenarios are considered, each resulting in a specific water abstraction pattern. The hydrologic consequences of each scenario are evaluated by means of a digital hydraulic groundwater model. -Authors


 

 

 

Ground Water
Volume 27, Issue 4, 1989, Pages 481-490  

 

Origin of the saline ground water in Wadi Ar-Rumah, Saudi Arabia

Sowayan, A.M., Allayla, R.

Second Author: Civil Engineering Dept., King Fahd Univ. of Petroleum and Minerals, Dhahran, Saudi Arabia.

__________________________________________________

Abstract

The aquifer contains highly saline water in the area where Wadi Ar-Rumah intersects the outcrop of the Saq Sandstone. The area is agriculturally important, but the saline water has caused problems due to intrusion into other parts of the aquifer as a result of heavy pumping. The geology, hydrogeology, and hydrochemistry of the area were examined and pertinent field data were used to explain the formation of the saline water. At the end of the last pluvial period, the ephemeral runoff in the wadi decreased and a clay layer was deposited on its floor. Ground water near the surface was evaporated by capillary draw and led to a concentration of solutes. A shallow clay layer prevented wadi flows from flushing out the saline ground water. -from Authors


 

 

 

Journal of Hydrology
Volume 107, Issue 1-4, 1989, Pages 193-222  

Numerical modeling of a multi-aquifer system in eastern Saudi Arabia

Rasheeduddin, M1.Show author details, Yazicigil, H2.Show author details, Al-Layla, R.I2.Show author details Correspondence address

1)      Arriyadh Development Authority, PO Box NO. 495, Riyadh 11411, Saudi Arabia, 2) Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

A numerical quasi-three-dimensional groundwater flow model was constructed for a multi-aquifer system in eastern Saudi Arabia to determine the hydraulic properties of the system and to evaluate the consequences of various development alternatives. The aquifers modeled were the Alat, the Khobar and the Umm Er Radhuma of Paleocene-Eocene age, which are hydraulically connected with intervening aquitards. Steady-state and transient model calibrations demonstrated considerable spatial variations in transmissivities of the aquifers and vertical leakances of the aquitards. The reliabilities of these parameters were checked through sensitivity analysis. The model results have confirmed the hydraulic interaction between the aquifers via intervening aquitards. The calibrated model was subsequently utilized to predict responses of the aquifers over a planning horizon of 14 years (1987-2000) under three development alternatives. -from Authors


 

 

 

Water Resources Development
Volume 5, Issue 1, 1989, Pages 56-62  

 

Alternative water management scenarios for Saudi Arabia

De Jong, R.L.Show author details, Al Layla, R.I.Show author details, Selen, W.J.Show author details Correspondence address

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

The socioeconomic future of the Kingdom of Saudi Arabia will to a large extent depend on the successful matching of its extremely limited water resources with demands for water primarily determined by population growth. Reviews and roughly quantifies the demand and supply parameters and then proceeds to analyze four scenarios for water resources management according to four different strategies. The multiobjective approach uses the goal programming algorithm, and the most significant output parameters appear to be the notional 'water sector cost' and the rate at which non-renewable groundwater will be mined and exhausted, thereby endangering the Kingdom's water security. -Authors


 

Hydrosoft Journal

Dec. 1990

A Variational approach to Navier-Stokes equations.

Khondaker, A.N.Show author details, Mohsen, M.F.N.Show author details, Al-Layla, R.I.Show author details

Civil Engineering University of Petroleum & Minerals, Dhahran 31261, Saudi Arabia

________________________________________________________

Abstract

A finite element formulation is presented using an appropriate variational form preserving the non-linearity of the Navier-Stokes equations. This variational function, previously used by Guymon and Scott, in connection with the diffusion convection equation, is also found to be viable for these non-linear equations. A solution algorithm was developed using the 'vorticity' and 'stream function' formulation of the Navier-Stokes equations. The dependent variables were approximated over each triangular element using linear interpolation polynomials. The application of the developed code to some numerical examples produced results comparable to existing methods and displayed the efficiency of the method. The method was found to be limited to low Reynolds numbers.


 

 

 

Critical Reviews in Environmental Control
Volume 20, Issue 4, 1990, Pages 231-256  

Groundwater contamination studies - the state-of-the-art

Khondaker, A.N.Show author details, Al-Layla, R.I.Show author details, Husain, T.Show author details Correspondence address

King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

With the increasing sense of awareness about our environment and the recognition of the need for its protection, the study of solute transport related to groundwater contamination has become the focus of numerous researchers. Different investigators approached the problem from many view points, and the resulting achievements are so extensive and scattered that it seems essential to inventory the completed works. This paper presents a systematic study of the available theoretical and experimental works. A complete picture of the present status of the problem is also provided, issues that remain obscure or unaddressed by the current day investigators are pointed out to facilitate future research directions and/or alternatives to advance technology for a greater understanding and more comprehensive analyses of the solute transport phenomena related to groundwater contamination.


 

 

 

Critical Review in Environmental Control

1990, Vol.20, No. 4 Page 231-256

Groundwater Contamination Studies - The State-of-the-Art

 

A. N. Khondaker1, R. I. AI-Layla2, and T. Husain3

 

1)        PhD Candidate and Lecturer, Dept. of Civil Engineering King Fahd University of Petroleum and Minerals, 2) Associate Professor, , King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia, 3) Research Engineer, Water Resources and Environment Division, The Research Institute, Dhahran, Saudi Arabia 

________________________________________________________________________________________________________________________________________________________________________

 

ABSTRACT

 

With the increasing sense of awareness about our environment and the recognition of the need for its protection, the study of solute transport related to groundwater contamination has become the focus of numerous researchers. Different investigators approached the problem from many view points, and the resulting achievements are so extensive and scattered that it seems essential to inventory the completed works. This paper presents a systematic study of the available theoretical and experimental works. A complete picture of the present status of the problem is also provided, issues that remain obscure or unaddressed by the current day investigators are pointed out to facilitate future research directions and/or alternatives to advance technology for a greater understanding and more comprehensive analyses of the solute transport phenomena related to groundwater contamination.

 


 

 

 

Water, Air, and Soil Pollution
Volume 61, Issue 1-2, January 1992, Pages 75-93  

 

Experimental study and numerical simulation of denitrification in saturated porous media

allayla, R.I.Show author details, Mohammed, N.Show author details, Husain, T.Show author details Correspondence address

Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia

__________________________________________________

Abstract

The effect of Denitrification on the behavior of nitrate in saturated sandy soil was studied in the laboratory and the results were compared with the temporal and spatial concentration of nitrate in nonreactive (without Denitrification) and reactive (with Denitrification) cases. A laboratory model was fabricated to study steady one-dimensional flow and to transport nitrate with or without Denitrification. Denitrification at various rates has been simulated with varied C:N ratios and detention time. Retardation constant, dispersivity, and degradation constants have been computed using existing analytical models supporting adsorption and zero and/or first order production or decay. It was found that such analytical models can be used to fit the concentration of nitrate in saturated porous media for a C:N ratio between 2 and 5.

The effect of Denitrification on the behavior of nitrate in saturated sandy soil was studied in the laboratory and the results were compared with the temporal and spatial concentration of nitrate is nonreactive (without Denitrification) and reactive (with Denitrification) cases. A laboratory model was fabricated to study steady one-dimensional flow and to transport nitrate with or without Denitrification. Denitrification at various rates has been simulated with varied C:N ratios and detention time. Retardation constant, dispersivity, and degradation constants have been computed using existing analytical models supporting adsorption and zero and/or first order production or decay. It was found that such analytical models can be used to fit the concentration of nitrate in saturated porous media for a C:N ratio between 2 and 5.

 

 

 

Environmental Technology
Volume 15, Issue 1, 1994, Pages 15-28  

Tertiary treatment of sewage effluent via pilot scale slow sand filtration

Farooq, S.Show author details, Al-Yousef, A.K.Show author details, Al-Layla, R.I.Show author details, Ishaq, A.M.Show author details Correspondence address

Department of Civil Engineering, King Fahd Univ of Petroleum Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

In view of limited information available about the performance of actual size slow sand filtration as a tertiary process in sewage treatment a pilot scale study was conducted over a period of one year using the secondary treated effluent from North Aramco Wastewater Treatment Plant, Dhahran, at a flow rate of 0.16 m hr-1 (2L min-1) to determine the process efficiency. Two sizes of local sand, i.e., effective size (ES) = 0.31, uniformity coefficient (UC) = 2.00; and ES = 0.56, UC = 1.64, were evaluated in terms of removal of major pollution parameters such as organic matter, micro-organisms and nutrients. Effective range of the filter depth was also investigated by conducting the experiments at three different depths of the sand bed, i.e., 135, 105, and 55 cm for each size of the sand. It was found that removals of BOD, COD, standard plate counts, nitrate, phosphate and sulphate vary from 79-92%, 40-60%, 88-93%, 17-30%, 8.3-84%, and 5-10%, respectively, at various sand depths for two different sizes of the sand.


 

Journal of Environmental Science & Health.

State-of-the-art review of bioremediation studies

Mohammed, N.a Show author details, Allayla, R.I.a Show author details, Nakhla, G.F.a Show author details, Farooq, S.a Show author details, Husain, T.b Show author detailsCorrespondence address

Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

_________________________________________________________________________________

Abstract

The state of the art bioremediation has been rapidly expanding during the last decade. Numerous articles are being published in a remarkable number of journals. Biodegradability of all possible organic pollutants is being tested in field and lab. New technologies are being discovered to biodegrade even the most recalcitrant organic chemicals. Many new books on bioremediation studies are also being written and edited. Information is scattered in books, journals, conferences and many other sources. The objective of this paper is to summarize the available existing literature on bioremediation studies. Issues covered are bioremediation in context with other remediation technologies, biodegradability of different organic compounds under different condition as reported in lab and fields studies, factors affecting bioremediation, and review of existing literature on modeling and case studies. Copyright 1996 by Marcel Dekker, Inc.


 

 

 

Arabian Journal for Science and Engineering
Volume 22, Issue 1B, April 1997, Pages 129-140  

 

Estimating flood quantiles in southwestern part of Saudi Arabia

Ishaq, A.M.a Show author details, Saada, N.M.a d Show author details, Allayla, R.I.a Show author details, Sheikh, A.K.b Show author details,Hussain, T.c

Department of Civil Engineering
Department of Mechanical Engineering
Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
Colorado State University, Fort Collins, CO, United States

__________________________________________________

Abstract

Estimating flood quantiles is an important requirement in the proper management of water resources in any country. In this study, regional regression analysis is performed for the purposes of estimating flood quantiles in some of the watersheds located in the western and southwestern parts of Saudi Arabia. The Generalized Least Square approach as opposed to the widely-used Ordinary Least Square approach is used in the regression analysis. The dependent variables of the regression analysis are the quantiles predicted by the Log Pearson Type III model and the independent variables are the physiographic variables such as area, main channel length, main channel slope, and watershed average slope. In contrast to the usual watershed physiographic variables, the watershed response time measured as time-to-peak of the flood stage curve and watershed order number are also used to predict the flood quantiles. Results show that the watershed response time measured as the watershed time-to-peak and the watershed order number are significant parameters in predicting flood quantiles in Saudi Arabia.


 

 

 

Arabian Journal for Science and Engineering
Volume 22, Issue 1C, June 1997, Pages 65-80  

Tidal effects on transport of contaminants in a coastal shallow aquifer

Khondaker, A.N.a Show author details, Al-Suwaiyan, M.S.a b Show author details, Mohammed, N.a Show author details, Allayla, R.I.a

King Fahd University of Petroleum and Minerals, Dhahran, Saudi Arabia
KFUPM Box 1979, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

The effects of tidal fluctuations on the spreading behavior of pollutants in an industrial site located near the Arabian Gulf was examined. Monitoring wells installed to observe the flow dynamics indicated that tides have an influence on the water level. A finite element model was used to simulate both groundwater flow and contaminant transport in the subsurface environment. The transport process modeling includes advection and dispersion. After calibration with field data, the model was applied to investigate the problem of groundwater contamination in the study area. The study of the tidal effects on the flow dynamics confirmed that the water table behavior is significantly influenced by the tidal fluctuation along the coastal boundaries. The model predicted a decrease in concentration of solute (as TDS) with time under the tidal influence indicating a loss of solute mass from the study area.


 

 

 

Environmental Technology
Volume 15, Issue 1, 1994, Pages 15-28  

Tertiary treatment of sewage effluent via pilot scale slow sand filtration

Farooq, S.Show author details, Al-Yousef, A.K.Show author details, Al-Layla, R.I.Show author details, Ishaq, A.M.Show author details Correspondence address

Department of Civil Engineering, King Fahd Univ of Petroleum Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

In view of limited information available about the performance of actual size slow sand filtration as a tertiary process in sewage treatment a pilot scale study was conducted over a period of one year using the secondary treated effluent from North Aramco Wastewater Treatment Plant, Dhahran, at a flow rate of 0.16 m hr-1 (2L min-1) to determine the process efficiency. Two sizes of local sand, i.e., effective size (ES) = 0.31, uniformity coefficient (UC) = 2.00; and ES = 0.56, UC = 1.64, were evaluated in terms of removal of major pollution parameters such as organic matter, micro-organisms and nutrients. Effective range of the filter depth was also investigated by conducting the experiments at three different depths of the sand bed, i.e., 135, 105, and 55 cm for each size of the sand. It was found that removals of BOD, COD, standard plate counts, nitrate, phosphate and sulphate vary from 79-92%, 40-60%, 88-93%, 17-30%, 8.3-84%, and 5-10%, respectively, at various sand depths for two different sizes of the sand.


 

 

 

 

Journal of Hazardous Materials
Volume 54, Issue 3, July 1997, Pages 155-174  

 

Modeling transport and biodegradation of BTX compounds in saturated sandy soil

Mohammed, N.Show author details, Allayla, R.I.Show author details Correspondence address

Research Institute, King Fahd Univ. Petrol. and Minerals, Dhahran 31261, Saudi Arabia

__________________________________________________

Abstract

Numerical models have been developed using finite difference and orthogonal collocation methods to simulate one dimensional transport with time-dependent pore water velocity. The modeling process includes sorption given by linear isotherm and biodegradation given by a variety of kinetics such as first-order, zero-order, Monod, non-growth associated Monod (Michaelis-Menten), Haldane and many other inhibitory and non-inhibitory kinetics. A number of initial and boundary conditions such as Dirichlet's, Neuman's, mixed, decaying, etc. have been modeled. The method of finite difference (for first order/zero order model only) and the method of orthogonal collocation (for all kinetics models) have been used to solve the governing transport equation. Numerical solutions have been verified with existing analytical solutions for special cases. Three models (first-order and/or zero-order, non growth associated Michaelis Menten, and Monod) have been inverted using a Gauss-Marquardt-Levenberg algorithm to assess the transport parameters. The models have been used to simulate one dimensional transport of BTX compounds in a pilot scale sand tank model. The data have been found to fit to all three kinetic models with acceptable coefficient of determination (R2) and parameter values. The high concentration data have been found to fit better to the Michaelis Menten and the Monod models than the first order/zero order model.

 

 

 

Effect of Groundwater Velocity on Pilot Scale Bioremediation of Gasoline Contaminated Sandy Aquifers

Journal

Water, Air, & Soil Pollution

Publisher

Springer Netherlands

ISSN

0049-6979 (Print) 1573-2932 (Online)

Subject

Biomedical and Life Sciences and Earth and Environmental Science

Issue

Volume 120, Numbers 3-4 / June, 2000

DOI

10.1023/A:1005203702132

Pages

315-329

Online Date

Monday, November 29, 2004

 

 

Effect of Groundwater Velocity on Pilot Scale Bioremediation of Gasoline Contaminated Sandy Aquifers

Niaz MohammedContact Information and Rashid I. Allayla1

(1) 

Center for Environment and Water, Research Institute, King Fahd University of Petroleum and Minerals, Dhahran, 31261, Saudi Arabia

 

Abstract 

 The effect of groundwater velocity onbioremediation of gasoline contaminated sandy soil has been investigated using a pilot scale sand tank model. The effect of hydrogen peroxide and contaminant concentration are also included. A factorial experiment has been conducted to study three factors, groundwater velocity, inlet BTX concentration and hydrogen peroxide dose. Observed concentration data collected from the sand tank model have been used for estimating the transport parameters. Three differentbiodegrdation kinetics, namely first-order/zero-order, Monod and Michaelis Menten (a modification of Monodkinetics considering no microbial growth) kinetics have been used to model the biodegradation. The data have been found to fit all three models with acceptable coefficient of regression. Groundwater velocity has been found to be the most significant factor governing the biodegradation rate constants(determined from the first-order rate constant) of BTX compounds. Hydrogen peroxide dose and BTX concentration have also been found to be significant factors.

 

 

 

 

Computational Mechanics
Volume 26, Issue 5, November 2000, Pages 409-418  

Viscous flow over a sphere with fluctuations in the free-stream velocity

Alassar, R.S.Show author details, Badr, H.M.Show author details, Allayla, R.Show author details Correspondence address

King Fahd Univ. Petrol. and Minerals, Dhahran 31261, Saudi Arabia

Abstract

The problem of viscous flow over a sphere with fluctuations in the free-stream velocity is considered. The governing conservation equations are expressed terms of the stream function and vorticity and solved using the series truncation method where the stream function and vorticity are approximated using finite series of Legendre and first associated Legendre functions. The effects of the Reynolds number, Strouhal number, and the amplitude of the fluctuations on the flow characteristics are studied. Results are presented for periodic variation of the drag coefficient, surface vorticity and pressure distributions for Reynolds numbers ranging from 5 to 100, Strouhal numbers ranging from π/4 to π, and amplitude of fluctuations from 0.0 to 0.5. The time variation of the velocity field during one complete cycle is presented in the form of streamline and equi-vorticity patterns. The periodic variation of the angle of separation as well as the length of the separation region are also presented.


Water, Air, and Soil Pollution
Volume 87, Issue 1-4, 1996, Pages 267-281
  

 

Simulation of in-situ bioremediation of phenol contaminated sandy aquifers: 1. Effect of sand sizes

Essa, M.H.Show author details, Farooq, S.Show author details, Nakhla, G.F.Show author details Correspondence address

King Fahd University of Petroleum and Minerals, Civil Engineering Department, Dhahran 31261, Saudi Arabia

Abstract

Laboratory scale porous media biofilm reactors were used to evaluate the effect of biofilm thickness on media porosity and permeability. Media tested consisted of three different sizes of sand (0.4, 0.3, and 0.2 mm). A set of fifteen columns was used in this experiment, five columns for each size of sand. Columns were operated under constant piezometric head (2.5 m) conditions, resulting in a decreasing flow rate with biofilm development. During the experiment, variations in the piezometric head, substrate concentration, and growth in biomass as well as volatile solids were monitored in space and time. Phenol (15 mg/L) was used as a growth substrate. The reductions in hydraulic conductivity were found to be 97% for the coarse sand (0.4 mm), 96% for the medium size sand (0.3 mm), and 93.7% for the fine sand (0.2 mm). The respective removal of phenol in these columns was 96% for the coarser sand, 97.9% for the medium size sand, and 98.8% for the finer sand. Steady-state effluent phenol concentrations occurred simultaneously with uniform hydraulic conductivity reduction after 50 days of operation. The concentration of volatile solids near the column inlets and outlets, after 58 days of operation, ranged between 9.8 and 4.04 mg/g for the coarse sand, 11.2 and 6.2 mg/g for the medium size sand, and 11.8 and 6.2 mg/g of sand for the fine sand, respectively. The number of colonies near the column inlets and outlets was 2800 1010/mL and 1480 1010/mL for the coarse sand, and 2840 1010/mL and 1520 1010/mL for the medium sand, and 2890 1010/mL and 2120 1010/mL for the fine sand. 1996 Kluwer Academic Publishers.

 


Journal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
Volume 31, Issue 7, 1996, Pages 1547-1574
  

 

State-of-the-art review of bioremediation studies

Mohammed, N.a Show author details, Allayla, R.I.a Show author details, Nakhla, G.F.a Show author details, Farooq, S.a Show author details, Husain, T.b Show author detailsCorrespondence address

Department of Civil Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
Research Institute, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia

Abstract

The state of the art bioremediation has been rapidly expanding during the last decade. Numerous articles are being published in a remarkable number of journals. Biodegradability of all possible organic pollutants is being tested in field and lab. New technologies are being discovered to biodegrade even the most recalcitrant organic chemicals. Many new books on bioremediation studies are also being written and edited. Information is scattered in books, journals, conferences and many other sources. The objective of this paper is to summarize the available existing literature on bioremediation studies. Issues covered are bioremediation in context with other remediation technologies, biodegradability of different organic compounds under different condition as reported in lab and fields studies, factors affecting bioremediation, and review of existing literature on modeling and case studies. Copyright 1996 by Marcel Dekker, Inc.