Evaluation of leaching behavior and immobilization of zinc in cement-based solidified products

This study has examined leaching behavior of monolithic stabilized/solidified products contaminated with zinc by performing modified dynamic leaching test. The effectiveness of cement-based stabilization/solidification treatment was evaluated by determining the cumulative release of Zn and diffusion coefficients, De. The experimental results indicated that the cumulative release of Zn decreases as the addition of binder increases. The values of the Zn diffusion coefficients for all samples ranged from 1.210-8 to 1.1610-12 cm2 s-1. The samples with higher amounts of binder had lower De values. The test results showed that cement-based stabilization/solidification treatment was effective in immobilization of electroplating sludge and waste zeolite. A model developed by de Groot and van der Sloot was used to clarify the controlling mechanisms. The controlling leaching mechanism was found to be diffusion for samples with small amounts of waste material, and dissolution for higher waste contents

Construction Waste Management in Croatia

This article discusses construction waste and its management in the territory of Croatia. In order to better understand the concept of waste, the first part of this paper discusses its origin, characteristics, and categorisation. In addition, it mentions special categories of waste defined within Croatian borders. All members of the European Union are encouraged to adopt a circular economy approach to manage these various types of waste. Furthermore, the article emphasises the necessity to construct legal landfills in addition to building management centres, recycling yards, and transfer stations, in order to reduce the formation of wild landfills, which result from irresponsible waste disposal. The second part of the article provides a detailed description of construction and demolition waste. In addition to the types of occurrences and the associated degree of hazard, a categorisation system is used. This system includes records and key numbers, and allows finding the appropriate species in the database with the corresponding key number. Modern technology has made it possible to recycle all types of waste, including construction waste, into secondary raw materials. Proper management is essential to achieve this goal. The first step involves prevention, diversion or conversion of waste into a resource. When these options are not possible, one of the recovery processes should be employed. Managing Construction Waste also provides a comprehensive explanation of recycling, which is given significant attention. The article concludes with an overview of the Republic of Croatia’s system for managing construction waste, which lags behind more developed countries, as well as offers examples of best practices and possible improvements

Monthly and Seasonal Variations of NO2, SO2 and Black-smoke Located Within the Sport District in Urban Area, City of Split, Croatia

This paper represents, for the first time, scientific data as a part of monitoring air quality in the city of Split. The city has a problem with the air pollution mostly caused by anthropogenic activities and partly by natural origin activities. This study presents results of monthly and seasonal variations of NO2, SO2 and black-smoke as well as the influence of meteorological parameters on observed concentration levels. Average seasonal values for SO2 ranged from 22.54 to 54.81 g m–3, for NO2 from 48.24 to 56.38 g m–3 and for black-smoke from 4.15 to 5.64 g m–3. The results obtained for SO2 and black-smoke were below, while for NO2 were above the limit value of pollutants in the air recommended by Croatian Government (Air Protection Act (OG 178/04); Regulation on limit values of pollutants in air (OG 133/05)). As the result of stable meteorological conditions (high temperatures and drought), the increase in SO2 concentration was significant in summer period, while the concentrations of NO2 and black-smoke were not significantly changed during year and did not depend on other parameters. (doi: 10.5562/cca1966