Madbuli H. Noweir

Study of heat exposure during Hajj (pilgrimage)

Heat stress presents a main problem to Muslim Hajeej (pilgrims) during Hajj (pilgrimage) season, particularly in summer. Records of the Saudi Ministry of Health show close relation between heat casualties and climatic heat load through consequent Hajj seasons. The present study was conducted to evaluate the climatic heat load in Hajj locations during summer of 1995 as well as just before and during the Hajj season of 1997. Heat measurements including: Ta, Tw, Tg, WBGT, relative humidity and air velocity were conducted through July–September 1995, and on March/April 1997, in 10 Hajj locations at morning, noon, afternoon and night. The highest WBGTs were at Haram court, Ghazzah area and Muna housing area, followed by Arafat areas and Muzdalefah, and the lowest at Azizia area. However, all the WBGTs were considerably higher than the ACGIH-TLV® for safe heat exposure, particularly during daytime; meanwhile, heat exposure considerably exceeded the ASHRAE comfort zone at all locations all times. The natural climatic condition is a major contributing factor to the overall heat load; moreover, potentiated by heat dissipated from Hajj activities, including Hajeej crowds, human activities, and the vehicles’ masses exhaust. This situation is further synergized by some pilgrims’ misbehavior (e.g. living in open sunny areas, using vehicles without roofs) and lack of awareness of the seriousness of heat exposure among them. An outline for a control strategy has been suggested based on planting open areas of Arafat and Muna, provision of air conditioned housing and tents in Muna, segregation of pedestrians from vehicles and their provision of shaded roads and rest areas, establishing more water spatters in Arafat and Muna, checking the performance of large vehicles before issuing their permits for operation during Hajj, providing vehicles parking isolated areas away from Hajeej tents, provision of ample amounts of quality drinking water in all Hajj locations, provision of ample optimal ambulance services, and dissemination of educational information to Hajeej for their taking advantage of Fiqh (religion rules) waivers in performing Hajj rituals to minimize their heat exposure, and for their personal protection.

NOISE POLLUTION IN TEXTILE, PRINTING AND PUBLISHING INDUSTRIES IN SAUDI ARABIA

A study of 20 factories belonging to textile, printing, publishing and paper products industries in Jeddah was conducted.Data on Leq, Maximum and Minimum SPL at different octave bands, as well as dBA, were collected. It has been found that textile,publishing and paper products industries are the most noisy industries. The paper is concluded with suitable recommendationfor noise control and worker protection.

Bioconversion of High Concentrations of Hydrogen Sulfide to Elemental Sulfur in Airlift Bioreactor

Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m(-3) h(-1) were achieved in the airlift bioreactor under investigation at a pH range 6.5-8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO < 0.2 mg/L) and at higher pH values. The sulfur oxidizing bacteria in the bioreactor tolerated accumulated dissolved sulfide concentrations >500 mg/L at pH values 8.0-8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8-8.5.Several bioreactor systems are used for biological treatment of hydrogen sulfide. Among these, airlift bioreactors are promising for the bioconversion of hydrogen sulfide into elemental sulfur. The performance of airlift bioreactors is not adequately understood, particularly when directly fed with hydrogen sulfide gas. The objective of this paper is to investigate the performance of an airlift bioreactor fed with high concentrations of H2S with special emphasis on the effect of pH in combination with other factors such as H2S loading rate, oxygen availability, and sulfide accumulation. H2S inlet concentrations between 1,008 ppm and 31,215 ppm were applied and elimination capacities up to 113 g H2S m−3 h−1 were achieved in the airlift bioreactor under investigation at a pH range 6.5–8.5. Acidic pH values reduced the elimination capacity. Elemental sulfur recovery up to 95% was achieved under oxygen limited conditions (DO < 0.2 mg/L) and at higher pH values. The sulfur oxidizing bacteria in the bioreactor tolerated accumulated dissolved sulfide concentrations >500 mg/L at pH values 8.0–8.5, and near 100% removal efficiency was achieved. Overall, the resident microorganisms in the studied airlift bioreactor favored pH values in the alkaline range. The bioreactor performance in terms of elimination capacity and sulfur recovery was better at pH range 8–8.5.

Noise Pollution in Metalwork and Woodwork Industries in the Kingdom of Saudi Arabia

This study was conducted in metalwork and woodwork industries in Jeddah Industrial Estate. The purpose of this study was to assess the magnitude of industrial noise exposure and to propose remedial actions. Noise was measured at different times of a day in 28 randomly selected factories and workshops. Results indicated that noise levels varied according to the type and size of a factory, and the type and number of machines used. Mean noise levels in metalwork factories were higher than those in woodwork factories. The highest noise levels were observed while manufacturing cans and forming steel reinforcement for concrete, where noise levels exceed 90 dB(A). All mean noise levels in all studied metalwork factories and in 50% of studied woodwork industries were higher than the standard level of 85 dB(A).

Quantitative safety analysis of a laboratory-scale bioreactor for hydrogen sulfide biotreatment using fault tree analysis

Numerous research activities are conducted all over the world to study biological treatment of H2S in laboratory‐scale bioreactors. Important hazards associated with these bioreactor systems include the escape of H2S gas and leakage of chemical/biological liquids, which have severe adverse effects on the involved labors, equipment, and materials. The objective of this article is to present a quantitative safety analysis of a laboratory‐scale continuous bioreactor system for H2S gas biotreatment using the fault tree analysis approach. Three unwanted top events were determined as the most hazardous events, being H2S leakage inside the laboratory, H2S leakage to outdoor from bioreactor outlet, and leakage of liquid chemical/biological solutions. The minimal cut sets and the probability of the occurrence of each top event were determined. The importance of cut sets and basic events were calculated, and priorities for control measures were determined. The analysis allows better decision on priority of control measures, and maintenance or replacement schemes of the system components in an endeavor to minimize the probability of failure or hazard occurrence. The presented analysis proves the usefulness of fault tree analysis in making quantitative risk assessment and safety analysis, which are important elements in laboratory safety management system.

Appraisal of work hazards and safety in the industrial estate of Jeddah

An environmental study for the appraisal of work hazards and safety in Jeddah Industrial Estate (JIE), Saudi Arabia has been conducted. The study is based upon a representative (stratified random) sample of 44 enterprises, including 52 plants and employing 5830 workers.Nearly 2/3 of the workers have heat exposure, orginating from climatic heat and heat dissipated from industrial operations, while exposure to noise is slightly less, and is attributed to noisy operations and machinery and to lack of meticulous maintenance; both exposures are mild in most of the plants and moderate in some. Mild exposures to nonionizing radiations (UV and IR) and to deficient illumination occur in 25% and 19.2% of the plants studied. Respiratory exposure to chemical agents (organic and inorganic dusts, metal fumes, gases and vapours — including asphyxiants, irritants, liver and nervous system offenders and acid and alkali mists) occurs in 75% of the plants, particularly in the medium-size enterprises plants; however, is mainly mild with a few moderate and severe exposures. Skin absorption contributes to absorption of chemical agents in 29% of the plants, and direct skin contact to chemicals (particularly to lubricating oils) occurs in 81% of the plants.Meanwhile, only eight plants, out of the 32 plants where controls for physical hazards are required (51.2%), apply engineering controls, and even in a few of these plants the efficiency of the control measures has been rated ‘bad’. A few of them provide personal protective equipment, and even no maintenance to this equipment is provided.The level of safety is better in the large plants than in the small and medium-size plants; the safety score is the best in the recently established plants, while is the worst in the plastic industry, which is relatively old. The appraisal of fire protection is better than that of the safety, due to efficient supervision of the General Directorate of Civil Defense (GDCD). However, most of the safety problems are managerial and are preventable.First aid is present in all enterprises, as required by the Saudi Labor Laws; however, an in-plant medical service is present in 75% of the large enterprises, in 31.6% of the medium-size and in only 17.6% of the small enterprises. Also, satisfactory medical, accidents and absenteeism records exist in only 15.9% of the enterprises; safety supervision exists in 27.3, and safety education exists in 91% of them, while no environmental monitoring is carried out in any enterprise. Sanitation facilities exist in satisfactory numbers in most of the enterprises; however, their maintenance is poor in most of them, due to lack of hygienic supervision. All enterprises dispose of their liquid wastes into the JIE sewerage system without any treatment, while the solid wastes are collected by the city authorities in 56.8% of them; both wastes are anticipated to cause environmental pollution problems.