The use of an electrogalvanic device for scale neutralisation is descibed in this paper. Physico-chemical analyses were performed before and after the treatment. The results were compared with those obtained by using magnetic water treatment device. By measuring some individual parameters and the implementation of chemical analysis, the satisfactory functioning of the electrogalvanic device was demonstrated. The quality of drinking water did notchange much after the water treatment method. The results of determination of calcium carbonate saturating index showed that the raw drinking water is incarbonate equlibrium as well as both treated water samples. The calcite/aragonite ratio was studied by means of microscopy and X-ray powder diffraction. Inspection of crystals formed during the experiments with microscopy indicated that aragonite crystal structure of the precipitates prevailed over the calcite stucture. The diffractograms showed that the share of aragonite increased after using the electrogalvanic device compared with raw drinking water samples where the share of calcite was higher.
COBISS.SI-ID: 16727830
This paper addresses the optimization-based design of water networks with complexity of industrial relevance. To overcome the challenges associated with the large scale processes, we focus on the integration of wastewater engineering concepts and models, together with optimization methods and solution algorithms. We propose a computer-aided framework for the design of water treatment and reuse networks. In the framework, optimization methods, problem analysis tools and wastewater engineering knowledge are integrated in a computer-aided environment, in order to facilitate the formulation and solution of the design problems.
COBISS.SI-ID: 17185046
The influence of fermentation temperature, agitation rate, and additions of carbon sources, nitrogen sources, vitamins and minerals on production of kefiran by kefir grains lactic acid bacteria was studied in a series of experiments. The main aim of the work was to increase the exopolysaccharide (EPS) production where customized milk was used as fermentation medium. It was proved that the controlling of culturing conditions and the modifying of fermentation medium conditions (i.e., carbon, nitrogen, mineral sources and vitamins) can dramatically enhance the production of the EPS. The temperature and agitation rate were critical for kefiran production during the 24 h cultivation of grains; our optimized conditions being 25°C and 80 rpm, respectively. In addition, when optimizing the effects of additional nutrition, it was found that lactose, thiamine, and FeCl3 led to the maximal production of EPS. The results indicate that nutrients can be utilized to improve the production of EPS and that good kefir grains growth does not appear to be a determining factor for a high production yield of EPS.
COBISS.SI-ID: 16645142
This contribution presents and discusses two multi-objective optimisation approaches considering total (direct and indirect) effects on the environment.Sustainability metrics, conventionally measuring direct harmful effects on the environment, are now upgraded with indirect effects in order to measure the unburdening the environment, e.g. due to the substitution of harmful with benign products. The first approach, based on a relative direct sustainability index, is now upgraded to a total sustainability index, and the second one, based on a concept of eco-cost and net profit, is extended to arecently introduced concept of eco- and total profit. These approaches are illustrated through a case study of the supply chain synthesis for producing biogas from organic and animal wastes. The results indicate that considering total effects enables obtaining more realistic solutions, than in those cases when only direct effects are considered. An appropriate trade-off between economic and environmental criteria can be established when performing a maximisation of total profit.
COBISS.SI-ID: 16020502
This contribution presents a simplified and more practical version of an objective dimensionality reduction method within multi-objective optimisation - a Representative Objectives Method. This method is based on similarities between several objectives in order to reduce the number of objectives to a minimum number of representative objectives. This method can be applied to different direct and total objectives. In this contribution the selected objectives are annual profit and total footprints. Total footprints are the sum of direct and indirect footprints where the direct footprints only consider the burdening of the environment, whilst the total footprints consider both the burdening and unburdening of the environment. This dimensionality reduction method is applied during a demonstration case study of regional supply chains regarding the evaluations of different total environmental footprints. This case study indicates that this simplified version of the Representative Objectives Method is easy to apply and enables the user to more easily understand multi-objective optimisation solutions. It represents a practical tool for performing the dimensionality reduction of criteria during the economic and environmental optimisation of different problems when considering total environmental footprints.
COBISS.SI-ID: 17446678