This study reviewed the use of microorganisms for bioremediation of wastewater. The aim was to ensure enhanced transfer of findings on bioremediation experiments at laboratory level for field applications, which is currently limited. Using empirical studies and specified microbes, bioremediation was shown to clear or reduce concentrations of many pollutants found in both industrial and municipal effluents with high efficacy. Findings established that bioremediation efficacy differs based on the microbes used, the characteristics of the targeted wastewater for cleansing and the physicochemical and biological characteristics of the polluted environs. It was also established that bioremediation is sometimes limited in refractory contaminant remediation due to microbe incompatibility with pollutant resulting to enzyme inhibition, generation of toxic substances and slow microbial metabolism capacity, which could prolong bioremediation processes and reduce the resultant decontamination efficacy. To overcome these challenges, this review recommended the uptake of advancements such as bio-stimulation and bioaugmentation for bettered biodegradation of contaminants. Additionally, the use of genetically engineered approaches to improve the innate characteristics of bioremediators towards recalcitrant pollutants was found to improve effectiveness. The review also suggested the use of consortiums and multiple bioremediation approaches to improve bioremediation outcomes in future. Bioremediation therefore, has high potential in cleansing wastewater pollutants and biotechnological advances could further improve its field application outcomes.
The purpose of this study is to investigate the potential opportunities and challenges of plastic products in Ethiopia. The study is qualitative in nature and a descriptive research design with the in-depth interview was used. The study employed both primary and secondary sources of data to investigate the study on hand. More specifically purposive sampling techniques were used to select the respondents for the interview. Discourse analysis was used in the study to recognize discursive interaction as a valuable tool for determining opinions, ideas, and facts about plastic products in Ethiopia. The study developed two different storylines regarding the opportunities and challenges of plastic products. As a result, the first storyline (S1) used taxing plastic products as an alternative strategy. The second storyline (S2) used banning plastic products as opposing strategy. The study finding implies that having a tax on plastic products could provide more opportunities for the country than banning them. More specifically, taxing plastic products will be more appropriate for the generation of revenue, employment, industrial process, construction process, and recycling in Ethiopia. On the other hand, a lack of proper collection systems, separation of the source of disposal, a properly designed operating system, clear authorities and sanitation rules, organizational capacity, and unreliable collection services were found to existing challenges of plastic products. Governments and policymakers shall play a critical role in developing the necessary legislative framework to encourage mitigation actions that contribute to the reduction of plastic waste at the source, as well as encouraging the cleanup of plastic pollution on coastlines. Public discussion on alternative packaging than the one-time use of plastic products is also needed. Public awareness is required to change customer attitudes, and separation of organic and non-organic waste across the cities.
This study assesses the level of radioactivity, its corresponding dose and risk in areas of intense agropastoral activities in the Mayo-Sava, Mayo-Tsanaga and Mayo-Kani Divisions of the Far North region of Cameroon. The ultimate aim is to show that beyond the geological structure and mineralogical composition of the soil, agricultural fertilizers and animal droppings from livestock farming can contribute significantly to the elevation of the40K-induced radioactivity level in an environment. Natural radionuclide analysis was carried out on 55 soil samples collected from the three aforementioned localities, using a laboratory NaI (Tl) gamma spectrometer. The mean activity concentrations of238U,232Th and40K were 41, 59 and 529 Bq/kg respectively. The total effective dose to the public and the risk of cancer morbidity were generated by RESRAD-ONSITE code version 7.2. The 0.7 mSv/year maximum total effective dose was estimated at time 𝑡= 38 years, with contributions of 56%, 37.3%, 3.9%, 2.1%, 0.7% and 0.07% from plant ingestion, external exposure, meat ingestion, milk ingestion, soil ingestion and inhalation, respectively. Potassium-40 (40K) from plant ingestion is the major contributor. The doses in the initial year of agropastoral activity and the total excess cancer risk were 0.3 mSv/year and 1.165×10-3 respectively. The40K contributions to effective dose from plant ingestion obtained in this work are high compared to areas where agropastoral activities are not intensive. This may be due to the various fertilizers and animal droppings distributed in nature which are very rich in potassium. Although potassium is essential to life, it is nevertheless necessary for radiation protection to take into account this type of radiological exposure which is not without harmful effects on the environment and health.
The proposed study described the application of innovative technology to solve the issues in a supply chain model due to the players’ unreliability. The unreliable manufacturer delivers a percentage of the ordered quantity to the retailer, which causes shortages. At the same time, the retailer provides wrong information regarding the amount of the sales of the product. Besides intelligent technology, a single setup multiple unequal increasing delivery transportation policy is applied in this study to reduce the holding cost of the retailer. A consumed fuel and electricity-dependent carbon emission cost are used for environmental sustainability. Since the industries face problems with smooth functioning in each of its steps for unreliable players, the study is proposed to solve the unpredictable player problem in the supply chain. The robust distribution approach is utilized to overcome the situation of unknown lead time demand. Two metaheuristic optimization techniques, genetic algorithm (GA) and particle swarm optimization (PSO) are used to optimize the total cost. From the numerical section, it is clear the PSO is 0.32 % more beneficial than GA to obtain the minimum total cost of the supply chain. The discussed case studies show that the applied single-setup-multi-unequal-increasing delivery policy is 0.62 % beneficial compared to the single-setup-single-delivery policy and 0.35 % beneficial compared to the single-setup-multi-delivery policy. The sensitivity analysis with graphical representation is provided to explain the result clearly.
Nowadays in worldwide agriculture, sustainable strategies are implemented to reduce negative effects on ecosystems created by conventional practice, mainly environmental pollution caused by intensive use of fertilizers and chemical plant protection products. Bacteria from the genus Pseudomonas can be considered biocontrol and plant growth-promoting agents due to their various plant beneficial traits e.g., siderophores production, phytohormones synthesis, antagonism against phytopathogenic fungi. This is a reason for increasing researchers’ interest in improving of existing or elaborating new technologies that enable the effective application of these bacteria in agriculture. Pseudomonads are non-sporulating bacteria and it is a major constraint for creating bioformulation for commercial use with a sufficiently high stable number of viable cells during shelf-life. Therefore, scientists are making efforts to improve techniques of bioformulations to enable large-scale production and use of pseudomonads under field conditions. The aim of this review is to describe traits of Pseudomonas spp. which are useful in plant protection and growth-promotion and to highlight examined techniques for preparing bioformulations containing pseudomonads with sufficiently long shelf life.
Carcinogenic hexavalent chromium is increasing worldwide due to the increased electroplating, welding and textile industry. On the other hand, molasses, the sugar factory’s byproduct with high organic compounds (sugars), may pollute the environment if it is not processed. However, microbial fuel cell (MFC) seems to be a promising technology due to its ability to produce electrical energy from pollutant degradation using microbes while reducing hexavalent chromium to trivalent chromium with less toxicity. Carbon felt was used at both electrodes. This research aimed to determine the effect of modifying the anode with rice bran and cathode with Cu catalyst towards electricity generation and pollutant removal in molasses and reducing Cr (VI) into Cr (III) using tubular microbial fuel cells. Moreover, the effect of mixing Sidoarjo mud and Shewanella oneidensis MR-1 as electricigen bacteria toward electrical energy production and pollutant removal was determined. Experiments revealed that the S/CM/AM variable, which only used Shewanella oneidensis MR-1 as an electricigen bacteria with both modified electrodes, produced the highest total power density of 530.42 mW/m2 and the highest percentage of Cr (VI) reduction of 98.87%. In contrast, the highest microbial population of 66.5 × 1010 cells/mL, 61.28% of Biological Oxygen Demand (BOD5) removal and 59.49% of Chemical Oxygen Demand (COD) were achieved by SSi/CM/AM variable, mixing Shewanella oneidensis MR-1 and Sidoarjo mud as an electricigen bacteria with both modified electrodes. Therefore, this study indicates that double chamber tubular microbial fuel cells may be a sustainable solution for managing molasses and carcinogen hexavalent chromium.
Water is an essential element that sustains life on this planet, yet it is threatened by human activities. With little attention paid to the waterfall as a source of a domestic water supply and a tourist spot for recreation, this study was designed to investigate one of the waterfalls in Iligan City, Philippines: Dodiongan Falls. The location of the study is a neighborhood of the city garbage dumpsite that due to an uncontrollable situation, releases dark-colored secretion from the treatment box as has been verified by the residents in the area; this posed a threat to their food security and livelihood. Assessing the physicochemical parameters, heavy metal concentration and Escherichia coli counts is very crucial in interpreting its water quality. All parameters such as the pH, alkalinity, turbidity, lead (Pb), mercury (Hg), and the E. Coli test were done following the standard procedures. The results revealed that the pH, alkalinity, turbidity, total lead (less than 0.01 mg/L) and total mercury concentration (less than 0.001 mg/L) at the three sites were in conformity with the guidelines of the World Health Organization and Philippine national water quality standards. However, the E. Coli count has increased downstream from 220 to 1,600 MPN per 100 ml, which exceeded the standard limit. With these findings, it is paramount that the creation of a management plan be initiated as soon as possible by the different governmental agencies in order to bring back the life of Dodiongan Falls.
To assess the heavy metals concentration in the coastal sediments of the southern Kuwait coast, Fe, Mn, Cu, Pb, Ni, Co, Cd and Cr were measured by inductively coupled plasma mass spectroscopy. Whereas, the south of Kuwait coast is characterized by the presence of tourist resorts, and commercial and oil exports harbors. Moreover, environmental indicators were used to help in evaluating the degree and the intensity of pollutants in these sediments. Geoaccumulation index (Igeo) revealed that the sediments of hard all Hamara and Al-Khiran coasts are moderately polluted by Cu, while Ras Al-Zour and Ras Al-Jula’ia coasts are moderately polluted by Cd. Moreover, the enrichment factor (EF) indicated that the sediments of Hadd Al-Hamara coast are severely enriched with Ni, Cr and Pb, while the Al-Khiran coast is moderate severely enriched with the same metals. Ras Al-Zour and Ras Al-Jula’ia coasts are severely enriched with Ni and very severely enriched with Pb. Simultaneously, all studied sites are extremely severely enriched with Cu and Cd. These results were confirmed by the results of the contamination factor (CF) and the soil pollution index (SPI) indicated that Hadd Al-Hamara and Al-Khiran coasts are highly contaminated with Cu and Cd, while Ras Al- Zour and Ras Al-Jula’ia coasts are highly contaminated with Cd. Generally, the pollution load index showed that the sediments of all studied sites are no heavy metal pollution (PLI < 1). Pollutants might be originated from commercial wastes and construction activities.