Biomedical subjects

Mohamed F Hamoda

Publications and source records attributed to Mohamed F Hamoda.

5 recordsLinked to original sources

PubMed2006

Movement of unlined landfill under preloading surcharge.

As organic solid waste is decomposed in a landfill and mass is lost due to gas and leachate formation, the landfill settles. Settlement of a landfill interferes with the rehabilitation and subsequent use of the landfill site after closure. This study examined the soil/solid waste movement at the Al-Qurain landfill in Kuwait after 15 years of closure as plans are underway for redevelopment of the landfill site that occupies about a km(2) with an average depth of 8-15m. Field experiments were conducted for 6 mo to measure soil/solid waste movement and water behavior within the landfill using two settlement plates with a level survey access, Casagrande-type piezometers, pneumatic piezometers, and magnetic probe extensometers. Previous results obtained indicated that biological decomposition of refuse continued after closure of the landfill site. The subsurface water rise enhanced the biological activities, which resulted in the production of increasing quantities of landfill gas. The refuse fill materials recorded a high movement rate under the imposed preloading as a result of an increase in the stress state. Up to 55% of the total movement was observed during the first 2 weeks of fill placement and increased to 80% within the first month of the 6-mo preloading test. Pneumatic piezometers showed an increase in water head, which is attributed to the developed pressure of gases escaping during the preloading period.

Biodegradation, Environmental↗

PubMed2006

Air pollutants emissions from waste treatment and disposal facilities.

This study examined the atmospheric pollution created by some waste treatment and disposal facilities in the State of Kuwait. Air monitoring was conducted in a municipal wastewater treatment plant, an industrial wastewater treatment plant established in a petroleum refinery, and at a landfill site used for disposal of solid wastes. Such plants were selected as models for waste treatment and disposal facilities in the Arabian Gulf region and elsewhere. Air measurements were made over a period of 6 months and included levels of gaseous emissions as well as concentrations of volatile organic compounds (VOCs). Samples of gas and bioaerosols were collected from ambient air surrounding the treatment facilities. The results obtained from this study have indicated the presence of VOCs and other gaseous pollutants such as methane, ammonia, and hydrogen sulphide in air surrounding the waste treatment and disposal facilities. In some cases the levels exceeded the concentration limits specified by the air quality standards. Offensive odors were also detected. The study revealed that adverse environmental impact of air pollutants is a major concern in the industrial more than in the municipal waste treatment facilities but sitting of municipal waste treatment and disposal facilities nearby the urban areas poses a threat to the public health.

Aerosols↗

PubMed2003

Performance-based characterization of a contact stabilization process for slaughterhouse wastewater.

This paper evaluates the effluent treatment plant of a slaughterhouse in Hawalli City, Kuwait processing 1100 heads of livestock a day. Results indicated that the proposed process effectively reduces pollution potential of slaughterhouse wastewater. Influent Chemical Oxygen Demand (COD) ranged from 3335 to 7580 mg L(-1), of which approximately 30% were in the form of suspended solids (SS). Removal efficiency was 77% for soluble COD and 82% for insoluble COD, at a volumetric load of 1.8 kg COD m(-3) d(-1). Values obtained for the biokinetic coefficients, floc uptake (FU), substrate removal efficiency (SRE), specific reaction rate (RR), maximum reaction rate (Rm) and Yield (Y) of the contact tank were higher than the range of values reported for other continuously fed activated sludge systems. In contrast to the contact tank, the aeration basin biokinetic coefficients were within the range of values reported. Contact process testing demonstrated that controlling solid recirculation to maintain a contact loading of about 120-150 mg COD g(-1) VSS in the contact tank generally resulted in high SRE. RR, Rm, and also in good settleability as indicated by SVIs being consistently below 150 mL g(-1). In the other hand, higher contact loadings of more than 150 mg COD g(-1) VSS. resulted in a significant deterioration in SRE, RR, Rm, and SVIs.

Abattoirs↗

PubMed2002

Nitrogen transformations during aerobic/anoxic sludge digestion.

Laboratory experiments were conducted to study and compare nitrogen transformations occurring under both aerobic digestion and aerobic/anoxic (A/A) digestion. The process performance was examined at different sludge residence times (SRTs), temperatures and anoxic cycles. Both modes of operation gave comparable solids reduction results. However, introduction of anoxic periods to aerobic sludge digestion appears to be a promising alternative to control pH during digestion through endogenous nitrate respiration (ENR). Operating an aerobic digester with an anoxic phase to achieve complete denitrification would also improve supernatant quality over that achieved solely by aerobic digestion. Alternating A/A operation can conserve most of the influent alkalinity and maintain near neutral pH condition over prolonged periods. The A/A digestion of mixed primary/waste-activated sludge achieved up to 43.7% reductions in volatile suspended solids, 33.7% removal of total nitrogen, and a specific ENR rate of 5.75 x 10(-2) mg NO3-N/mg VSSd. Optimum results were obtained at 10 d SRT, 30 degrees C temperature, and 50% anoxic cycle length.

Ammonia↗

PubMed2002

Report: management problems of solid waste landfills in Kuwait.

This paper evaluates current operational practices in municipal solid waste landfills in Kuwait to provide existing knowledge on uncontrolled landfilling and associated problems of solid waste disposal in developing countries. The current landfilling practices are safe neither for humans nor for the environment. The landfill sites receive all kinds of wastes such as food wastes, oil products, debris, dead animals, agricultural wastes, chemical wastes, wastewater and sewage sludge. The wastes are dumped, spread and compacted in an uncontrolled manner and cover material is not applied regularly. Dust created within the landfill site and gas emissions cause a public nuisance. The characteristics of leachate formed indicate high organic content and presence of heavy metals, salts and nutrients. There are no provisions for leachate or landfill gas collection at the landfill sites. Recommendations for adjustment in landfill operation have been made in recognition of the transition period that is experienced in proceeding from the past and present to the future management of landfills in Kuwait to safeguard the public health and protect the environment.

Environmental Monitoring↗