Environmental Engineering
M. Iqhrammullah; S. Saudah; M. Monalisa; F. Fahrurrozi; S.A. Akbar; S.S. Lubis
Abstract
BACKGROUND AND OBJECTIVES: The presence of heavy metals, specifically cadmium, in the environment poses significant threats to both ecological systems and human health. However, microalgae have shown potential in addressing this issue through their ability to absorb cadmium and produce valuable biomass, ...
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BACKGROUND AND OBJECTIVES: The presence of heavy metals, specifically cadmium, in the environment poses significant threats to both ecological systems and human health. However, microalgae have shown potential in addressing this issue through their ability to absorb cadmium and produce valuable biomass, making them a promising solution for bioremediation. Among the various microalgae species, Chlorella vulgaris stands out as a suitable candidate due to its potential for biodiesel production and its capacity to effectively absorb cadmium. Therefore, the main objective of this study is to assess the toxicity of cadmium on Chlorella vulgaris cells using network meta-analysis as a methodology.METHODS: A comprehensive search was conducted on Scopus, Scilit, Google Scholar, and Web of Science to identify relevant studies published from 1 January 1990 to 16 January 2024. Only studies that reported the cell number of Chlorella vulgaris as a result of cadmium exposure were considered for inclusion. The collected data were then subjected to Bayesian frequentist network meta-analysis, utilizing standardized mean difference and a 95 percent confidence interval as measures of effect size. Additionally, a linear regression analysis was performed to examine the dose-dependent impact of cadmium toxicity.FINDINGS: Dose-dependent toxic effects of cadmium on Chlorella vulgaris were evident (R-square of more than 0.90), particularly at a concentration of 1 part per million, deemed as the maximum tolerable threshold. Prolonged exposure revealed a concentration-dependent reduction in cell viability, suggesting potential lifespan shortening. A comparison of growth stimulants, gibberellic acid and brassinolide (standard means differences of 1.7 and 3.8, respectively), in mitigating cadmium toxicity indicated the latter superior effectiveness in sustaining microalgal survivability. The presence of high nitrogen and low phosphorous levels was found to be significantly associated with a reduction in Chlorella vulgaris cells due to cadmium exposure.CONCLUSION: This research has provided conclusive proof of the harmful effects of cadmium on Chlorella vulgaris through the implementation of Bayesian frequentist network meta-analysis, offering valuable insights for environmental management practices. The findings reveal concentration-dependent effects of cadmium toxicity. The survivability of Chlorella vulgaris is determined by the compositions of macronutrients nitrogen and phosphorous. Comparative analyses highlight the superior protective effect of brassinolide over gibberellic acid in mitigating cadmium toxicity. Overall, the findings highlight the potential of Chlorella vulgaris in both bioremediation of heavy metals and biomass production.
Environmental Engineering
E. Riani; N.A. Butet; M. Ansori; M.R. Cordova
Abstract
BACKGROUND AND OBJECTIVES: Cinangka Village in Bogor Regency is a traditional used battery recycling center in West Java, Indonesia. The smelting process was operated in open space, but because of adverse impacts, it has ceased since 2010. This activity generated a large amount of solid waste, categorized ...
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BACKGROUND AND OBJECTIVES: Cinangka Village in Bogor Regency is a traditional used battery recycling center in West Java, Indonesia. The smelting process was operated in open space, but because of adverse impacts, it has ceased since 2010. This activity generated a large amount of solid waste, categorized as hazardous and toxic materials, thereby polluting the air, land, and water. Because an area of Cinangka Village has been converted into a fishing pond, it is necessary to investigate whether the fish that live in this pond are accumulating heavy metals, thereby threatening and harming humans as consumers. This research is important for the innovative remediation of land contaminated with used battery smelting waste.METHODS: Analysis of lead, zinc, arsenic, and iron levels in water, sediment, fish, and aquatic plants, as well as histomorphology analysis of several fish organs, was performed. The safety aspect of consuming fish originating from this location was also calculated. For the used battery recycling area, lead and iron contaminate the environment in the highest concentrations, while arsenic and zinc are always detected but in low concentrations.FINDINGS: The results showed that sediment and water around the pond, previously a burning area of used battery smelting but 12 years after cessation, are polluted by heavy metals, not only lead, zinc, arsenic, and iron. Other metals are present because lead and lead oxide plates are impure and associated with other minerals. According to the lead concentration, the soil/sediment is still categorized as hazardous and toxic material and becomes a pollutant for the ecosystem. Water hyacinth plants that live in ponds are densely cultivated and contaminated with heavy metals. They can become heavy metal phytoremediators on the land where traditional used battery burning was performed. Goldfish from this area are contaminated with high levels of heavy metals and are unfortunately unsafe for consumption because zinc is perilous. Adults are only allowed 3 grams per week, while children may not consume goldfish from this fishing pond. Contaminating heavy metals also cause various damage to fish organs, namely, edema in the kidneys, melano-macrophage centers in the spleen and liver, edema and hyperplasia in the epithelial gills, and fatty degeneration in the liver and its lysed ovary cells.CONCLUSION: Consequently, land in Cinangka Village is still categorized as hazardous, and toxic waste and should not be converted into a fishing pond because the soil is a point source of pollution that contaminates fish with high concentrations of heavy metals and damages their organs. Consuming these goldfish will harm health and thus is prohibited for children. Cleaning and remediation of the environment is necessary and must cover the entire area. Meanwhile, water hyacinth plants can be used as phytoremediators in freshwater ponds to reduce heavy metals
Environmental Engineering
N.D. Takarina; N. Matsue; E. Johan; A. Adiwibowo; M.F.N.K. Rahmawati; S.A. Pramudyawardhani; T. Wukirsari
Abstract
BACKGROUND AND OBJECTIVES: Zeolite has been recognized as a potential adsorbent for heavy metals in water. The form of zeolite that is generally available in powder has challenged the use of zeolite in the environment. Embedding powder zeolite in a nonwoven sheet, known as a zeolite-embedded sheet can ...
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BACKGROUND AND OBJECTIVES: Zeolite has been recognized as a potential adsorbent for heavy metals in water. The form of zeolite that is generally available in powder has challenged the use of zeolite in the environment. Embedding powder zeolite in a nonwoven sheet, known as a zeolite-embedded sheet can be an alternative to solve that. Another challenge is that information and models of zeolite-embedded sheet removal efficiency are still limited. The novelty of this study is, first, the development of a zeolite-embedded sheet to remove heavy metals from water, and second, the use of the random forest method to model the heavy metal removal efficiency of a zeolite-embedded sheet in water.METHODS: The heavy metals studied were copper, lead and zinc, considering that those are common heavy metals found in water. For developing the zeolite-embedded sheet, the methods include fabrication of the zeolite-embedded sheet using a heating procedure and heavy metals adsorption treatment using the zeolite-embedded sheet. The machine learning analysis to model the heavy metal removal efficiency using zeolite-embedded sheet was performed using the random forest method. The random forest models were then validated using the root mean square error, mean square of residuals, percentage variable explained and graphs depicting out-of-bag error of a random forest.FINDINGS: The results show the heavy metal removal efficiency was 5.51-95.6 percent, 42.71-98.92 percent and 13.39-95.97 percent for copper, lead and zinc, respectively. Heavy metals were reduced to 50 percent at metal concentrations of 10.355 milligram per liter for copper, 171.615 milligram per liter for lead and 4.755 milligram per liter for zinc. Based on the random forest models, the important variables affecting copper removal efficiency using zeolite-embedded sheet were its contents in water, followed by water temperature and potential of hydrogen. Conversely, lead and zinc removal efficiency was influenced mostly by potential of hydrogen. The random forest model also confirms that the high efficiency of heavy metals removal (>60 percent) will be achieved at water potential of hydrogen ranges of 4.94–5.61 and temperatures equal to 29.1 degrees Celsius.CONCLUSION: In general, a zeolite-embedded sheet can adsorb diluted heavy metals from water because there are percentages of adsorbed heavy metals. The random forest model is very useful to provide information and determine the threshold of heavy metal contents, water potential of hydrogen and temperature to optimize the heavy metal removal efficiency using a zeolite-embedded sheet and reducing pollutants in the environment.
Environmental Engineering
S. Dhanasekar; R. Sathyanathan
Abstract
BACKGROUND AND OBJECTIVES: Recent investigations indicated that continuous use of fertilizers and pesticides in agricultural fields not only deteriorated soil health but also caused a deleterious effect on surface and groundwater bodies. Treating such wastewater using microalgae has shown higher nutrient ...
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BACKGROUND AND OBJECTIVES: Recent investigations indicated that continuous use of fertilizers and pesticides in agricultural fields not only deteriorated soil health but also caused a deleterious effect on surface and groundwater bodies. Treating such wastewater using microalgae has shown higher nutrient removal and biomass efficiency. Moreover, microalgae are proven to be miniature factories that augment the huge potential of biofuel. The aim of this study is to evaluate the different light intensities required for Chlorella vulgaris algae to remove nutrients from synthetic agricultural wastewater in a fabricated bubble column photobioreactor. Additionally, the research findings focus on assessing the degradation of organic pollutants and biomass generation under different light conditions.METHODS: In this study, synthetic agrochemical wastewater was treated in a bubble column photobioreactor with blue, red, sunlight, and white light conditions. The treatment was conducted in a batch process with a hydraulic retention time of 21 days, using light intensity of 1800–2800 luminescence and a temperature maintained at 25–28° degrees Celsius.FINDINGS: Under different lighting conditions, the blue light condition exhibited a higher biomass concentration of 3.99 gram per liter, with an estimated heat energy value of 1.278 kilojoule per liter. Moreover, in the blue light condition, scanning electron microscopy analysis showed no significant changes in the shape of Chlorella vulgaris and energy-dispersive X-ray analysis elemental composition exhibited the lowest oxygen-to-carbon ratio (1.03). Fourier transform infrared spectroscopy was used to illustrate the functional group of microalgae under different lighting conditions. The lipid, protein, carbohydrate, and amino acid contents were 3329–3332, 2116–2139, 1636–1645, and 545–662 per centimeter, respectively. The higher biomass potential from the wastewater treatment shows significant benefit in terms of feedstock and biofuel production.CONCLUSIONS: The present investigation identified the nutrient reduction and biomass productivity to be more in blue light condition for Chlorella vulgaris algae. The investigation also assessed the potential of lipid, carbohydrate, and protein content in Chlorella vulgaris, which indirectly evaluates the biofuel potential of the species.
