The impacts of industrial wastewater contamination on the geotechnical properties of clayey soil have been studied in the research presented in this paper. The contaminant in question is industrial wastewater released from Thi-Qar oil refinery as a by-product of production, and the soil samples obtained from Thi-Qar oil refinery plant in Al-Nassyriah (a city located in the south of Iraq). The geotechnical properties of contaminated soil samples were compared with those of intact soil to measure the effects of such a contaminant. The soil samples were obtained from three locations in the study area; representing the highly contaminated area, the slightly contaminated area, and the intact area used as a reference for comparison of test results. The results of the tests showed that the contaminant causes an increase of natural moisture content, field unit weight, Atterberg’s limits, and maximum dry unit weight, as well as an increase of the compression index and the coefficient of vertical consolidation. Also, the contaminant causes a decrease in specific gravity, the optimum moisture content initial void ratio, the swelling index, the coefficient of permeability, and cohesion between soil particles.
The Henaya Irrigated Perimeter (HIP) is an agricultural area irrigated by treated wastewater (TWW) of Ain El Hout treatment plant. Various analyses have shown that i) this water has low concentration of heavy metals and toxic elements, ii) the average values of the physicochemical parameters for 136 samples are satisfactory (29.2 mg O2∙dm–3 for chemical oxygen demands – COD, 13.14 mg O2∙dm–3 for biological oxygen demands – BOD, 14.2 mg∙dm–3 of suspended matter – SM, 1.82 mg∙dm–3 of N-NO3, 7.7 for pH and 927.74 μS∙cm–1 for electric conductivity – EC). Thirdly, it contains a high number of bacteria and nematodes (7200 CFU∙(100 dm3)–1 for faecal coliforms and 30 eggs∙dm–3 for intestinal Nematodes) which makes it dangerous for groundwater contamination. The objective in this work is to characterize the TWW and evaluate the impact of it use for irrigation on the quality of Hennaya groundwater. Before this, one has to prove that there is an amount of TWW that feeds the water table to show that there is a risk of pollution. We then estimated the aquifer minimum recharge value by TWW using the Thormthwaite meth-od. The estimation has given 92 mm which is an important quantity. The results of the groundwater microbiological anal-yses reveal no sign of contamination. The cause is the efficiency of the degradation of pollutants of the Vadose zone. The soil purifying power Md of the HIP was evaluated by the Rehse method and gave values ranging from 2.1 to 12.7 which indicated a complete purification.
The remarkable development of sanitation in Morocco has inevitably led to the production of sludge generated from wastewater treatment plants in increasing quantities. Consequently, the problem of sludge management becomes persistent and worrying.
The aim of this paper was to contribute to the study of sewage sludge management issue in Morocco by identifying the various constraints hampering the sustainable disposal and/or recovery of municipal sewage sludge and drawing up rec-ommendations for the decision-makers. Moreover, in the context of improving by learning from best practices and seeking common solutions regarding this problematic, benchmarking with other countries has been conducted as well.
To carry out this study, a methodological approach was defined based on bibliographic research, surveys, interviews and benchmarking.
The constraints hampering the sustainable management of sludge are numerous and complex, they have not been tech-nical and environmental but also a regulatory, institutional-organizational and economic-financial nature yet. Therefore, municipalities, government and academia ideally would be encouraged to participate in the decision-making process re-garding the management of sewage sludge. Technical solutions, when coupled with stakeholder participation, can lead to policy implementation with a higher chance of improving the present situation.
In the case of Morocco, when comparing with others sludge recovery and disposal routes, land application (reuse in ag-riculture, silviculture and rehabilitation of degraded soils) remains the most environmentally friendly option, as well as a sustainable and economically viable solution.
The paper presents the results of studies on the changes in the PAHs concentration during pre-filtration and ultrafiltration (UF) processes. In the study, biologically treated wastewater (after denitrification and nitrification processes), discharged from the biological treatment plant and used in coke plant, was used. A gas chromatography-mass spectrometry (GC-MS) was used in order to qualify and quantify the PAHs. Sixteen PAHs listed by EPA were determined. The wastewater samples were collected three fold and initially characterized for the concentration of nitrate nitrogen, ammonium nitrogen, COD, TOC and pH. In the first step, wastewater was filtrated on the sand bed. Total concentration of 16 PAHs in the treated wastewater before initial filtration was in the range of 44.8‒53.5 mg/L. During the process the decrease in the concentration of the most studied hydrocarbons was observed. Concentration of PAHs after initial filtration ranged from 21.9 to 38.3 μg/L. After the initial filtration process the wastewater flew to the ultrafiltration module and then was separated on the membrane (type ZW-10). The total concentration of 16 PAHs in the process of ultrafiltration was in the range of 8.9‒19.3 mg/L. The efficiency of removal of PAHs from coke wastewater in the process of ultrafiltration equaled 66.6%. Taking into account the initial filtration, the total degree of removal of PAHs reached 85%. The obtained results indicate the possibility of using the ultrafiltration process with the initial filtration as additional process in the coke wastewater treatment.
The aim of the study was to determine the impact of various methods of oil mixing with wastewater on
properties of synthetic municipal wastewater containing edible oil (SMW+0.02% m/v rapeseed oil). The study was
carried out in 3L glass, cylindrical reactors to which SMW+0.02% were introduced. Various methods of its mixing
with water were applied: mechanical mixing (SMW+0.02%+mixing) and sonication (SMW+0.02%+ultrasounds).
The wastewater was sonicated at 35 kHz for 30 min. The constant temperature conditions were maintained during
the experiment for each mixing method (15°C, 20°C and 30°C). The analysis of parameters (pH, COD, BOD5
and
long chain free fatty acids concentration) of raw wastewater and after 2, 4, 6, 24, 48 and 72 hours of inoculation
was performed to determine the effect of mixing method.
The most signifi cant changes in wastewater chemical parameters after the introduction of the oil were observed
in the case of COD. For SMW+0.02%+ mixing a slow increase in COD within 24 hours of the process was observed.
In the case of SMW+0.02%+ultrasounds the increase and the decrease of COD value were observed in reference
to the initial value. The changes in acids concentrations observed in reactors with SMW+0.02%+ultrasounds were
referred to the ones observed in reactors with SMW+0.02%+mixing but changes were more intense in the fi rst
reactor. The use of ultrasounds in pre-treatment of wastewater resulted in the intense appearance of palmitic acid
for 6 hours. Regardless of the emulsion formation method (mixing or ultrasounds), the concentration of oleic acid
and linoleic acid was reduced. The biggest changes in free fatty acids concentration were observed for palmitic,
oleic and linoleic acids after 24 hours.
In the paper toxicity assessment of hospital wastewaters samples was performed using direct-contact
tests consisting of five species, which represent three different trophic levels of the food chain. IC50 or EC50 values were estimated for each tested organism: Pseudokirchneriella subcapitata IC50/72h 18.77%, Daphnia magna
EC50/48h 20.76%, Thamnocephalus platyurus EC50/24h 22.62%, Artemia salina EC50/24h 59.87% and Vibrio fisheri
EC50/15min 46.17%. Toxic potential of hospital wastewater was described using a system of wastewater toxicity
classification. The toxic units (TU) values estimated for each test indicate that hospital wastewaters are toxic
(Class III). The variable results of the tests’ sensitivity confirmed the need of application of microbiotests battery with organisms of different trophic levels.
Sewage and solid waste can be a valuable source of materials used directly or indirectly in manufacturing of usable products. These processes are associated with elimination of pollutants from liquid and
solid wastes. The best-known methods of waste management are production of biogas and composting. This
paper focuses on the possibility of obtaining biomass as a source of protein feed (whose value, in terms of the
composition of aminoacids and microelements, is comparable with conventional feed, e.g. soymeal, bonemeal
or fishmeal). Sewage components for bacterial, fungal, algal and vascular plants’ culture are characterized as
a source of protein feed. Methods of industrial scale production of enzymes, mainly proteases and lipases that
have broad applications in various industries, are discussed. Development perspectives of inexpensive methods
of usable products from waste production are showed. Interdisciplinary nature of presented issues, which requires cooperation of specialists in biology, chemistry and technology, is emphasized.
Biochemical Oxygen Demand (BOD) is an important factor used to measure water pollution. This article reviews recent developments of microbial biosensors with respect to their applications for low BOD estimation. Four main methods to measure BOD using a biosensor are described: microbial fuel cells, optical methods, oxygen electrode based methods and mediator-based methods. Each of them is based on different principles, thus a different approach is required to improve the limit of detection. A proper choice of microorganisms used in the biosensor construction and/or sample pre-treatment processes is also essential to improve the BOD lower detection limit.