by Javad Yahaghi, Alireza Bazargan

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 34-44; https://doi.org/10.53623/tasp.v2i1.54

382 views
Abstract The use of radio frequency for water and wastewater treatment is a topic that has not been extensively explored. In this study, the effect of a HydroFlow S38 device (Hydropath Holdigs) inducing 150 KHz radio frequency (RF) has been investigated, removing color, forming coagulant flocs and their sedimentation, and the removal of bacteria. Experiments were first conducted on synthetic samples, and then on landfill leachate from the Aradkooh waste processing and landfilling complex (Kahrizak) in Tehran, Iran. The results of the experiments showed that RF had little to no effect on de-coloring in the absence or presence of sodium hypochlorite. Also, the coagulation and flocculation of ferric chloride remained unaffected. However, the use of RF was shown to reduce the number of bacteria significantly. The inductance of RF alone, without any other aid or chemical/physical treatment, was able to reduce the bacterial count by 35%. These findings provide motivation for future research regarding the use of RF for bacteria inactivation.[...] Read more. Full text

by Selvaraju Sivamani, Mutharasu Kavya, Vignesh Vinusha

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 27-33; https://doi.org/10.53623/tasp.v2i1.53

209 views
Abstract Textile industries are the second largest water-consuming industries, next to agriculture. This research is aimed at investigating the utilization of fly ash as a low-cost adsorbent to treat hot wash liquor by employing one factor at a time. Contact time, effluent dosage, pH, mass of adsorbent, temperature, particle size, and agitation speed have been varied to find the optimum conditions for dye removal from hot wash liquor by fly ash. The results from the sorption process show that the maximum dye removal of 56.07% has been obtained at a time of 5 min, an effluent to water ratio of 9:1, pH of 11, an adsorbent dosage of 0.55 g/mL, a temperature of 27 °C, a fly ash particle size of 128 m and an agitation speed of 100 rpm. The analysis of the results was performed through adsorption capacity and percentage colour removal. Hence, the results suggested that fly ash could be used as an effective adsorbent for treating dyehouse effluents.[...] Read more. Full text

by Zaniah Ishak, Sa’diah Salim, Dilip Kumar

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 1-12; https://doi.org/10.53623/tasp.v2i1.26

700 views
Abstract One of the most environmentally friendly methods to treat wastewater, especially synthetic dyes, is the production of activated carbon from agricultural waste. Tamarind seeds were transformed from negative-value waste into activated carbon in order to study the removal of synthetic dyes. The particular agro waste was soaked in ZnCl2 for chemical activation to increase its surface area and enhance its porosity. Physical activation of tamarind seeds was done by the carbonization process by burning at a temperature of 300 °C for 1 hour and cooling for 24 hours before washing with HCL to activate a pore surface for the tamarind seeds' carbon. The effects of parameters related to the adsorption of the dyes by tamarind seed activated carbon, such as contact time, initial concentration, absorbance dosage, and pH, were studied. The experimental data found that adsorption on both synthetic dyes exhibited a Langmuir isotherm in which the correlation value, R2, was 0.9227 (methylene blue) and 0.6117 (Reactive black 5). Meanwhile, the rate of adsorption for methylene blue (MB) and Reactive black 5 (RB5) by tamarind seed activated carbon was found to be well fitted in a pseudo-second-order model. More research is needed to meet the standard effluent of dyeing wastewater from the industrial sector.[...] Read more. Full text

by Kuok Ho Daniel Tang, Noura M. Darwish, Abdullah M Alkahtani, Mohamed Ragab AbdelGawwad, Peter Karácsony

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 59-75; https://doi.org/10.53623/tasp.v2i1.72

1281 views
Abstract Biological removal of dyes has been advocated due to its simplicity, cost-effectiveness, and low operational requirements in comparison to physicochemical methods of treating dye effluents. This paper aims to compare the efficiency of biological removal of dyes using bacteria, algae, and fungi, including yeasts, besides presenting the recent advances in the field. This paper reviewed scholarly articles published mainly between 2010 and 2021. It found bacteria could degrade a myriad of dyes. Different bacteria could degrade the same dye with different efficiencies. Similarly, one bacterial species could degrade multiple dyes with varying efficiencies. Though regarded as having a faster rate of dye biodegradation than fungi, this review finds bacteria to have comparable performance to fungi in decolorizing dyes, and it is worth mentioning that a few yeast species were reported to have very high efficiency in decolorizing dyes. Mixed bacteria or bacteria-fungus cultures were generally found to have better dye-decolorizing efficiency than pure cultures. Algae have relatively lower efficiency than bacteria and fungi in decolorizing dyes and might require longer contact time. New advances such as genetic engineering as well as immobilization of microorganisms and enzymes could improve the efficiency of dye biodegradation. Nonetheless, before biological removal of dyes can be feasibly applied, there are limitations that need to be overcome. Major limitations include the inconsistent performance of various organisms in decolorizing dyes; the complexity of optimization; inability to completely decolorize dyes; potential formation of toxic by-products upon decolorization of dyes; safety concerns of immobilization materials; and cost and technical feasibility of biological removal of dyes. This review has the significance of highlighting the important bottlenecks of the current biological dye removal technology, which could pave the way for breakthroughs in this domain of research.[...] Read more. Full text

by Jia Hui Chung, Nur Hasyimah, Norelyza Hussein

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 13-26; https://doi.org/10.53623/tasp.v2i1.27

1368 views
Abstract Nanotechnology is currently an upward trend in diverse fields, and therefore, its application will be reviewed in this paper. One of the nanotechnologies which can be used in environmental remediation is carbon nanotube (CNT). Its excellent mechanical and chemical properties allow it to have better achievement in remediating a wide range of organic and inorganic pollutants. CNT can be categorized into two types: single-walled carbon nanotube and multi-walled carbon nanotube. Due to urbanization, various types of pollutants have been released into the environment in great amounts. For instance, estrogen is the hormone generated and released from animals and humans. However, the overconcentration of estrogen affects the physiology of biological life. Besides, pesticides are frequently used by farmers to increase the fertility of the land for agricultural purposes, while heavy metals are commonly found during anthropogenic activities. Long-term absorption of heavy metals into the body tissues will accumulate toxic effects, leading to body system dysfunction. Hence, CNT technologies, including adsorption, membrane filtration, disinfection, hybrid catalysis, and sensing and monitoring, can be applied to remediate these pollutants. However, the application of nanotechnology and CNT faces several challenges, such as production costs, toxicity, ecological risks, and public acceptance. Application of CNT also has pros and cons, such that the lightweight of the CNT allows them to replace metallic wires, but dealing with nano-sized components makes it challenging.[...] Read more. Full text

by Risky Ayu Kristanti, Wilawan Khanitchaidecha, Gaurav Taludar, Peter Karácsony, Linh Thi Thuy Cao, Tse-Wei Chen, Noura M. Darwish, Bandar M. AlMunqedhi

Trop. Aqua. Soil Pollut. 2022, 2(1), pp 45-58; https://doi.org/10.53623/tasp.v2i1.68

593 views
Abstract Soil contamination is a major issue that must be prioritized, as food safety is mostly determined by soil quality. Soil quality has deteriorated significantly across the world with the continued expansion of industrial growth, urbanization, and agricultural activities. Soil contamination has become a growing issue and a barrier that must be addressed if we are concerned about re-establishing a healthy ecosystem. The activity is mostly driven by human activities, which include the use of pesticides, chlorinated organic pollutants, herbicides, inorganic fertilizers, industrial pollution, solid waste, and urban activities. While many methods have been developed to remediate significant pollutants generated by these activities, their degree of application may be constrained or inappropriate for a specific location. Parameters such as treatment duration, safety, and efficacy of soil/pollutant treatment all play a part in selecting the best appropriate technique. These technologies have been classified into three broad categories: physical, chemical, and bioremediation. This review shows and talks about thermal desorption (TD), which is a common way to clean up polluted soil.[...] Read more. Full text