A study using coagulation-flocculation and ultrafiltration (UF)methods for pulp and paper millsć wastewater (WW)was carried out. The reduction efficiencies of turbidity and chemical oxygen demand (COD), the removal efficiency of total suspended solids (TSS) and absorbance at 254 nm were the main evaluating parameters. Using coagulation-flocculation, the efficiencies of alum and polyaluminum chloride (PACl)were studied, when used alone and when coupled with flocculant aids. During the coagulation-flocculation process,use of a single coagulant, the coagulant dosage, and the pH, play an important role in determining the coagulation efficiency. At the optimum PACl dosage of 840 mg L-1 and optimum pH of 9.0, turbidity reduction was found to be 94.5%. A combination of inorganic coagulant and flocculant, or polymer was applied, in which PACl was used coupled with the polyelectrolytes Organopol WPB20 and WPB40. PACl coupled with Organopol WPB20 by optimal pH 9 gave a 98.3% reduction of turbidity, 91.9% removal of TSS, and a 60.2% reduction in COD. Ultrafiltration trials were carried out on a pilot scale. A tubular module was used with ceramic membrane. This membrane is a multi-channel membrane with an active surface layer made of Al2O3 and ZrO2. Within the acidic range, the turbidity and TSS were removed at above 99%.
COBISS.SI-ID: 15551254
The growing importance of sustainable development as a policy objective has initiated a debate about those suitable frameworks and tools useful for policymakers when making a sustainable decision. Composite indicators (CIs) aggregate multidimensional issues into one index, thus providing comprehensive information. However, it is frequently argued that CIs are too subjective, as their results undesirably depend on the normalization method, a specific weighting scheme, and the aggregation method of sub-indicators. This article applies different combinations of normalization, weighting, and aggregation methods for the assessment of an industrial case study, with the aim of determining the best scheme for constructing CIs. The applied methodology gradually aggregates sustainable development indicators into sustainability sub-indices and, finally, to a composite sustainability index. The normalization methods included in this analysis are: minimum-maximum, distance to a reference, and the percentages of annual differences over consecutive years. Equal weightings, the ćbenefit of the doubtć approach, and budget allocation process were used for determining the weights of individual indicators and sustainability sub-indices. The linear, geometric, and non-compensatory multi-criteria approaches (NCMCs) were used as aggregation methods. The NCMC is modified to fit the two-level aggregation, then to sub-indices, and finally to a composite sustainable index. Also, a penalty criterion is introduced into the evaluation process with the aim of motivating the company to move towards sustainable development. The results are analyzed by variance-based sensitivity analysis. According to the results the recommended scheme for CIs construction is: distance to a reference-benefit of the doubt-linear aggregation.
COBISS.SI-ID: 16055318
This study presents a multi-criteria optimization of a regional network producing bioproducts and food from biomass, including direct (burdening), indirect (unburdening) and total (direct + indirect) footprints. The generic model for the optimization of regional networks for the production and consumption of energy from biomass in the entire production network (Čuček et al., 2010) has been upgraded for the simultaneous evaluation of sustainable development based on life cycle assessment. More profitable and environmentally-friendly solutions are obtained when considering total footprints and not only direct footprints.
COBISS.SI-ID: 15839766
The study of environmental, economic and social footprints as indicators for measuring and assessing sustainable development was performed. This contribution also presents a number of tools that can be used for the assessment of sustainable development, a number of individual footprint calculators, graph-based tools and mathematical programming tools.
COBISS.SI-ID: 15840022
The objective of this contribution is to perform the sustainable mixed-integer linear programming (MILP) synthesis of biogas processes based on life cycle assessment (LCA). An aggregated model previously developed by authors for the efficient optimization of biogas processes has been upgraded with LCA, using the novel concept of eco-profit. Eco-profit is defined as the difference between burdening (eco-cost) and unburdening (eco-benefit) the environment, where eco-cost and eco-benefit calculations are based on LCA. The advantage of eco-profit is that it is expressed in monetary units. Therefore, eco-profit and economic profit can be merged together and the preferred solutions are those with maximal total profit. The single-and multi-objective optimizations were performed on a model of the biogas production processes. Within the former, economic, eco- and total profit were maximized separately and, within the latter, maximization of economic profit vs. eco-profit was introduced. All the results obtained from single and multi-criteria optimization show that biogas production is a sustainable alternative that provides an important eco-profit.
COBISS.SI-ID: 15787798