Recovery of Waste Leather From Tanneries as Aggregate in Composite Materials

This study proposes a recovery method for waste leather from tanneries, with high chromium content, by incorporating it into a composite material with cement matrix. The natural aggregates were substituted with CRT (cathode ray tubes) glass waste, with high lead content, originated from televisions and monitors dismantling. The material technological production flow was as follows: grinding skin (two types of skin: black and brown were used), mixing the ingredients after own recipes, pouring the mixture into molds, maturation, demoulding. The new material obtained was submitted to leachability tests to determine, using AAS (Atomic Absorption Spectrometry), the total chromium and lead concentration released from the material. The results showed that Cr and Pb were well retained in the cement matrix. The low levels of total Cr and Pb concentration were recorded at pH = 9-10 and pH = 12, for the composite containing black leather waste and and at pH = 2-3 and pH = 12 for the composite containing brown leather waste. Mechanical tests were also provided to evidence the mechanical properties of the composite. The new composite material obtained may be considered as construction material and can be classified in mortars class because of the size of the used aggregate (CRT glass waste). The objective of this study was to obtain a composite material that can be used as material for construction, in compliance with current standards in construction and environmental legislation. The proposed method for leather waste recovery is viable and environmentally friendly and could bring economic benefits. Keywords: leather, waste, CRT, composite, material.

Assessment of Heavy Metals Content in the Proximity of a Contaminated Site From Cluj-Napoca (Romania)

The present study was conducted in the proximity of a contaminated site from Cluj-Napoca city (Cluj County, Romania), where metal processing activities have been carried out for decades. Metal content and physico-chemical parameters were analyzed in soil, water and sediment samples, while organic matter (OM) and total organic carbon (TOC) was additionally analyzed for the soil samples. The sources of heavy metals were evaluated based on multivariate statistical analysis, while the soil and sediment contamination degree was assessed based on specific pollution indices. The calculated indices indicated a significant pollution with Cd and Pb, which may represent a risk if the area would become a residential area. Keywords: heavy metals, contaminated site, soil pollution indices, multivariate statistical analysis, Cluj-Napoca

Determination of Petroleum Hydrocarbons Content in Soils From Suplacu de Barcău, Romania

The level of pollution with petroleum compounds was evaluated in Suplacu de Barcău area based on the assessment of total petroleum hydrocarbons (TPH) concentrations in soil. As source of contamination, one active and another inactive petroleum extraction wells were chosen, and the concentrations were determined by fluorescence spectrometry. The results indicated alarming exceedances of the intervention thresholds, especially in the area where the activity is stopped, thus indicating long-term accumulation of pollutant and persistence in soil. Keywords: petroleum hydrocarbons, soil pollution, TPH, fluorescence spectrometry

The Evolution of Rural Clusters Within the Cluj Metropolitan Area

The identification of the metropolitan area was limited to the surrounding localities in a radius of about 30 km around Cluj-Napoca. This distance is considered in EU the best practice for the development of the peri-urban space. The Cluj Metropolitan Area (CMA) is located in Cluj County, the north-western development region of Romania. The Cluj Metropolitan Area is composed from voluntary association of communes plus the city of Cluj-Napoca, forming an urban network composed of two metropolitan rings. The first metropolitan ring is the purpose of our study. The transformation of communes into residential and complex clusters is also analyzed. The seven localities inside the first ring had significant changes in population and land use between 2002 and 2020. The increase of the population and decrease of the agricultural land area are premises in achieving urban homogeneity in the metropolitan area. Keywords: Cluj Metropolitan Area, metropolitan rings, urban space, rural clusters.