Journal of Environmental Engineering and Landscape Management

Evaluation of water permeability in compacted sand-bentonite liners from landfill using planning and factorial analysis

2024-07-26T08:40:43+03:00

Compacted Clay Liners (CCL) are designed to prevent environmental contamination in landfills. These layers are designed with low permeability soils, which are difficult to obtain. To this end, bentonite can be added. The objective of this work is to evaluate the reliability of factor analysis on the hydraulic performance of sand-bentonite mixtures. Two types of designs were used, with the variables controlled: compaction energy (CE), water content (U) and percentage of bentonite (B). Experimental layers were made to obtain water permeability (kw). The results showed that CE and B are, respectively, the factors that most influence permeability. The application of adequate energy promotes better accommodation of bentonite soil particles in the voids in the sand, which, when moistened, undergo an expansion process, reducing the voids in the layer. All of these parameters can be optimized by using a curvature design to obtain kW. Therefore, knowledge of CCL kw is essential to ensure the safety of the local environmental environment.

Clinoptilolite- and glauconite-based sorbents for lead removal from natural waters

2024-08-13T18:27:16+03:00

The aim of the research is to determine the effect of heat treatment and microwave irradiation on the sorption properties of a natural clinoptilolite and glauconite to Pb2+ ions. To improve the sorption capacity the samples were heat treated at 550 °C for 3 hours or microwaved at 790 W for 30 minutes. The XRD and XRF analysis present the content of investigated samples and prove the increase in the sorption capacity after treatment. After contact with Pb, its content in the natural clinoptilolite increased to 2.66%, and in the thermally treated – to 6.035%. The PbO content in natural glauconite increased to 3.9%, but after microwaving it reached 5.2% of the total sample weight. Heat treatment is useful for improving the sorption capacity of clinoptilolite, and microwave irradiation can significantly increase the adsorption capacity of glauconite.

Effects of evergreen trees on mental restorative quality of winter landscapes

2024-08-23T18:27:29+03:00

Compared with other seasons, winter usually has low mental restorative quality due to the lack of greenness. Reasonably adding evergreen trees to winter landscapes can improve the quality. However, what proportion, species and planting site of evergreen trees are better for mental restoration? To address this question, two original pictures (describing two landscape types) and 24 manipulated pictures (including three categories and four grades of proportion of evergreen trees) were collected, and 381 respondents were employed to score the mental restorative quality of each picture. The results revealed that planting evergreen trees in the landscape with water was more efficient in promoting mental restoration than planting them in the landscape without water. Adding broad-leaved evergreen trees was much better than adding coniferous trees and the mixture of the two. And, for the landscape with water, moderate proportion of evergreen trees possessed significantly higher mental restoration than low or high proportion.

Evaluation of noise exposure levels of pedestrians in suburban Chennai, India

2024-09-13T18:27:55+03:00

The study assessed traffic noise exposure levels of citizens walking on the sidewalks at important road crossings in commercial land zone regions of Chennai’s suburbs. The noise data from signalized and unsignalized intersections are collected with a class I sound level meter for peak and non-peak hours from 6 AM to 10 PM. Different noise indices like A-weighted equivalent continuous noise level (Leq), Traffic Noise Index (TNI), Noise Pollution Level (Lnp) and Noise Climate (NC) are calculated and compared with Central Pollution Control Board (CPCB, 2017) and WHO standards. The inhabitants’ noise exposure levels are at an average value of 80–107.1 dB(A) which is alarmingly higher than the threshold levels of 70 dB(A) by WHO. A Risk Exposure Assessment (REA) questionnaire survey conducted on the area revealed that unsafe health situations persist for the public in the study regions.