An up-flow structured-bed reactor subjected to recirculation and intermittent aeration (SBRRIA) was operated under varying influent conditions. The influent COD/N ratio was adjusted by maintaining a stable organic loading rate (average of 1.07 kgCOD m-3 d-1) and changing the nitrogen loading rate from 0.1 to 0.4 kg N m-3. Therefore, three different COD/N ratios were tested: 9.7±1 (Scenario 1); 7.6±1 (Scenario 2) and 2.9±1 (Scenario...

Research background: A strong industrial base is essential for achieving long-term sustainable economic growth and export competitiveness. In that sense, manufacturing remains a significant contributor to exports in the CEE countries. However, its role and its influence vary between CEE economies and change over time. Purpose of the article: The main objective of this paper is to compare the determinants of the international competitiveness,...

Nowadays, the use of mathematical models and computer simulation allow analysis of many different technological solutions as well as testing various scenarios in a short time and at low financial budget in order to simulate the scenario under typical conditions for the real system and help to find the best solution in design or operation process. The aim of the study was to evaluate different concepts of biochemical processes and...

Modern wastewater treatment plants (WWTPs) should maintain a balance between three combined sustainability criteria, including effluent quality, energy performance and greenhouse gas (GHG) emissions. All of these criteria were considered in the integrated plant-wide model developed in this study. The proposed model incorporates new features, including: (i) the addition of associated facilities to the overall energy balance and...

For a given graph G, a nonempty subset S contained in V ( G ) is an alliance iff for each vertex v ∈ S there are at least as many vertices from the closed neighbourhood of v in S as in V ( G ) − S. An alliance is global if it is also a dominating set of G. The alliance partition number of G was defined in Hedetniemi et al. (2004) to be the maximum number of sets in a partition of V ( G ) such that each set is an alliance. Similarly,...