Key Engineering Materials Vol. 1002

Abstract: This paper demonstrates the feasibility of ensuring radiation safety of solid substances that comprise environmental objects and have surfaces contaminated with radioactive substances. The identified problem is solved by utilizing the natural property of anti-radiation self-protection. To reintroduce structures and buildings contaminated with radionuclides into economic circulation, it is recommended to dismantle them, grind the materials, and mix the resulting mass. The proposed method is made possible by transforming the surface contamination of these objects into a uniform distribution of radionuclides throughout the mass of the contaminated substance. This uniform distribution will remain consistent in products made from the received raw materials. By implementing this approach, it is feasible to reintroduce large volumes of radioactively contaminated materials into the economic cycle and dispose of them in contaminated areas.

Abstract: Wastewater treatment plants, particularly anaerobic digesters, face significant challenges related to the deposition of struvite, a mineral scale composed of magnesium ammonium phosphate hexahydrate. The formation and accumulation of struvite can lead to blockages in the treatment system, reducing flow rates and overall plant efficiency. This article explores the necessity of struvite removal for proper plant function and the potential for struvite recovery due to its rich nutrient content, specifically phosphorus and nitrogen, which can be repurposed in agriculture. Struvite recovery not only mitigates mineral deposition problems but also addresses the ecological risks associated with nutrient-rich effluents. The excess nutrients in wastewater effluent can contribute to water pollution, leading to eutrophication, algal blooms, and oxygen depletion, negatively impacting aquatic ecosystems and aquatic life. Furthermore, as the world's phosphorus reserves are finite and depleting, recovering phosphorus from wastewater aids in conserving this non-renewable resource. To facilitate efficient struvite recovery, it is crucial to control the formation of struvite crystals. Key factors affecting this process include pH, temperature, supersaturation, and mixing energy. Understanding the optimal conditions for these parameters is vital for maximizing phosphorus recovery. Various technologies such as chemical precipitation, biomineralization, seeding, ultrasound, and electrochemical are being studied to enhance struvite recovery, offering sustainable and innovative approaches to address this challenge. Overall, this review explores the various techniques and technologies utilized to recover phosphorus in struvite form which contributes to the efficient and sustainable management of wastewater treatment systems.

Abstract: Investigating the intricate microbial communities within a textile wastewater treatment system is crucial for understanding their potential role in the process, and possibly for process optimization in the future. Dye-containing wastewater sludge samples were collected from a textile industry treatment plant. Employing total genomic DNA extraction, amplicon sequencing, and sequence data analysis, this research investigated the microbial community composition in three treatment tanks. Rarefaction curves confirm adequate sequencing depth, with the aeration tank displaying the highest reads. Alpha diversity reveals richer microbial communities in the anoxic tank, while all samples demonstrate similar diversity and species richness. Proteobacteria dominate at the phylum level, predominantly in the aerobic tank, signifying their involvement in nitrogen removal. Conversely, anoxic sludge features Planctomycetota and Thermotogota, potentially participating in anaerobic processes. Genus-level analysis highlights the potential significance of SM1A02 in nitrogen metabolism under anoxic conditions, while Denitratisoma dominates in aerobic tank, indicating denitrification as the main process in this tank. This study offers valuable insights into the microbial community members present in the textile wastewater treatment system, and their potential roles, towards a more sustainable biodegradation strategies of dye-containing wastewater.

Abstract: Heavy metal pollution has been a primary environmental concern that arises from various human activities, including industrial development and technological advancement in manufacturing processes. Conventional wastewater treatment technologies for addressing heavy metals from industrial effluents involve using expensive and hazardous chemicals, which create secondary pollution if the disposal of the used absorbent is not appropriately handled. Phytoremediation is an alternative way for wastewater treatment towards green and sustainable development. This study investigated the duckweed uptake ability from the Lemnaceae family and its surface morphology after phytoremediation. Overall, the studied duckweeds demonstrated the ability to remove the zinc ions from the synthetic wastewater with an initial zinc concentration of 10 mg/L and 300 mg/L at the ambient conditions with a 16:8 hours photoperiod. The highest zinc ions removal rate from 300 mg/L zinc synthetic wastewater was performed by Wolffia arrhiza on Day 5 (69.16 %), followed by Lemna minor (58.88 %) and Spirodela polyrhiza (50.52 %). The removal of zinc ions can be proven by the surface morphology of the duckweeds, in which numerous particles attached to the duckweeds can be observed through scanning electron microscopy (SEM) images after phytoremediation. The zinc weight percent in all the studied species increased after phytoremediation. Hence, this study concludes that duckweed species can be chosen as accumulators during phytoremediation to remove zinc ions from the sources within a short period.