Advances in Environmental Technology
Volume:9 Issue: 2, Spring 2023

Herein, a pilot study on the removal of ammonia from surface water using the integration of struvite precipitation and breakpoint chlorination is reported. A two staged pilot plant with a capacity of 1000 liters (1 m3) per run (LPR) was utilized, of which Stage 1 comprised struvite precipitation and Stage 2 comprised breakpoint chlorination. Optimum conditions (i.e., Stage 1) for struvite precipitation were 110 mg/L of Mg and P dosage (concentration), 150 rpm of mixing speed, 60 minutes of contact time, and lastly, 120 minutes of sedimentation, while optimum condition for the breakpoint chlorination (i.e., Stage 2) were 30 minutes of mixing and an 8:1 Cl2-NH4+ weight ratio. The synergistic effects of this hybrid system proved to be effective, with Stage 1 increasing the pH from 6.8 to 10.1, reducing Mn (≥97.0%) and Fe (≥99.6%) concentrations steeply, and concomitantly deactivated E coli and TPC to ≥ 99% and ≥91%, respectively, while ammonia was reduced from 5.4 mg/L to 2.7 mg/L-N (51.8 %). In Stage 2, i.e., breakpoint chlorination, ammonia was reduced from 2.7 mg/L to 0.02 mg/L-N whilst fully depleting residual microorganisms. Finally, the OPEX amounted to $ 0.31/m3; however, there is a potential for cost savings (≈53.2%) by replacing Kh2PO4 with waste phosphoric acid. Lastly, the results from this techno-economic evaluation study showed great potential compared to similar technologies, making this approach a game-changer towards the prudent management of elevated levels of ammonia amongst other problematic contaminants.

The capacity of Bambusa Tulda (BT) with chemical improvements to remove Malachite Green (MG) from water bodies is the main topic of this research. These improvements were achieved by employing an idealised Taguchi L16 orthogonal array design. The pH, starting dye concentration, bioadsorbent dose, and contact duration were all elements considered during the treatment process. Each one was found to have an impact. According to the findings, pH, preliminary dye concentration, contact duration, and bio-adsorbent dose in that order were the major elements in the elimination of MG dye. The optimal specific nitrification rate (SNR) conditions were determined to be pH-3, an initial dye concentration of 100 mg/L, a bio-adsorbent dose of 0.20 g/100 mL, and a contact time of 90 minutes. Contact time and bio-adsorbent dose were shown to have an effect on the results, while pH was the most relevant factor overall. This was confirmed using analysis of variance (ANOVA). Adsorption occurred in a monolayer in the Langmuir isotherm model. The chemical may include hydroxyl and carboxyl groups, according to the Fourier transform infrared spectroscopy (FTIR) data. Scanning electron microscopy was used to examine the exterior morphology of the Bambusa Tulda. Malachite Green dye may be removed from wastewater using a bio-adsorbent made from chemically enhanced Bambusa Tulda.

Wastewater management in petrochemical industries plays an effective role in reducing their environmental consequences. This study utilized life cycle assessment and carbon footprint methodologies to assess these environmental impacts. The objectives of the investigation were pursued using the ReciPe 2016, Cumulative Energy Demand, Cumulative Exergy Demand approaches, and sensitivity analysis. The outcomes of the endpoint analysis revealed that damage to resources, human health, and ecosystems received more than 98% of the total impact due to electricity consumption. Furthermore, electricity consumption and COD were responsible for the most significant midpoint-level consequences. The sensitivity analysis showed that a change of approximately 20% in electricity and chemical oxygen demand had the most significant impact on the ozone depletion category. The primary gas emitted as a result of the wastewater treatment process was carbon dioxide, which accounted for 99.78% of the carbon footprint associated with the process. Based on these findings, it can be inferred that replacing the current energy source with renewable alternatives would reduce over 90% of the environmental impacts of the wastewater treatment process in these industrial units.

The photocatalytic degradation of Quinalphos, an organic pesticide, in the presence of modified ZnO metal composites, namely ZnO/MgO and ZnO/SnO2, was investigated at normal pH in the presence of sunlight. The structural and morphological properties of both the synthesized nanocomposites were characterised by different spectral techniques. The effect of pesticide concentration, catalyst dosage, and pH on the photocatalytic degradation efficiency was investigated. The photocatalytic activity of the respective nanocomposites on the degradation of Quinalphos was confirmed by UV-Visible spectroscopy. Moreover, the recycling ability of the prepared nanocomposites was also conducted and analyzed. However, the photocatalytic efficiency of ZnO/SnO2 nanocomposite was more efficient than the ZnO/MgO nanocomposite for the treatment of pesticide effluent, achieving 98 % and 95 % of total organic carbon (TOC) and chemical oxygen demand (COD) removals, respectively. The present study therefore concluded that the ZnO/SnO2 nanocomposite was the more stable and well organised composite, which could be the preferred treatment of industrial and agricultural wastewater containing organic contaminants within a short span of time.

The “river-sea” geochemical barrier is studied slightly in terms of the variety of pollutants, sedimentation, and degradation. At the same time, problems related to oil pollution, in particular the genesis of hydrocarbons, are almost never covered. This study was dedicated to the origin, concentration, and composition of hydrocarbons in the bottom sediments of the Chernaya River (Black Sea, Crimea) estuarine zone. The features of the marginal filter zone of the river were considered. N-alkanes in the range of C11-C36 were identified in the bottom sediments of the studied water area. It was noted that there was persistent oil pollution (degraded hydrocarbons) in the water area of Sevastopol Bay, adjacent to the confluence of the river. The accumulation of terrestrial material increased as it moved from the river to the sea. The application of various molecular markers displayed the predominately allochthonous origin of the hydrocarbons in the bottom sediments. As a result of the study of molecular markers by using principal component analysis (PCA) and analysis of variance (ANOVA) analysis, three leading factors responsible for hydrocarbon input to the bottom sediments water area were identified. The first one (36.53 % of the total variation) was associated with n-alkanes of natural and anthropogenic input. The second factor (19.52 % variation) was associated with allochthonous organic matter, including petroleum and bacterial destruction. The third factor (10.74 %) was associated with mainly allochthonous routes of organic substances entering the bottom sediments of the water area.

Fires in atmospheric tanks, which are widely used in chemical process industries, are rare. Still, if they occur, they will have irreparable environmental consequences; thus, this study aimed to model and evaluate the environmental consequences of pool fires and determine the area. The restriction was performed due to the presence of a benzene pyrolysis tank. The consequences of accidents regarding an atmospheric storage tank in a petrochemical complex were investigated with PHAST 8.22 software. After qualitative risk assessment, four scenarios were selected in two weather conditions. Consequence modeling was performed using the relevant data, and after analyzing the results of a pool fire, the resulting restricted area was determined. With increasing leak diameter, the consequences of a fire were wider; the restricted area of about 100 meters in scenario S4 was more than in the other scenarios due to the formation of a pool fire in the hot season. The restricted area resulting from ​​the consequence of the pool fire with a delay in scenario S2 in the cold season was also equivalent to the consequence of both types of pool fires in scenario S3 in the hot season and was 88 meters. Atmospheric conditions also affected the consequences of pool fires. The occurrence of a pool fire also affected some of the side reservoirs. Therefore, designing a comprehensive emergency action plan is suggested in which domino events and the reciprocal consequences of disturbed reservoir accidents are examined through outcome assessment.