Systematic Design, Optimization, and Sustainability Assessment for Generation of Efficient Wastewater Treatment Networks

Due to population growth and economic development, there has been an increase in global wastewater (WW) generation footprint. There are different technologies associated with the wastewater treatment (WWT) process. The challenge is to select technologies that minimize the cost of treatment, as well as meet purity requirements. Further, there is a need to integrate sustainability analysis to facilitate a holistic decision. With the application of systems engineering, sustainable and cost-effective solutions can be achieved. In this work, we apply systems engineering to generate a sustainable and cost-effective solution. A superstructure was generated by categorizing technologies into four treatment stages. After modeling all functional equations for each technology, an optimization problem was formulated to determine the best path for the treatment process. Mixed-integer non-linear programming (MINLP), which implements a 0–1 binary integer constraint for active/inactive technologies at each stage was used. Sustainability analysis was performed for each representative case study (municipal and pharmaceutical WWT) using the sustainable process index (SPI). The total cost of municipal WWT is 1.92 USD/m3, while that for the pharmaceutical WWT is 3.44 USD/m3. With the treatment of WW, there is a reduction of over 90% ecological burden based on the SPI metric.

Evaluation of environmental footprint of wheeled tractors

Effective management of agricultural machinery helps to save financial and material resour-ces, and also reduces environmental pollution. Traditional environmental impact assessment me-thods do not involve the life cycle analysis, so environmental footprint method can help to evaluate farming, identifying threats and measures of mitigation the negative impacts. Growing amount of tractors used in agricultural sector increase the negative impacts to environment, so it becomes im-portant to properly assess farming. The aim of this paper is to determine the environmental footprint of wheeled tractors of Lithuanian farmers and agricultural companies and its development trends using sustainable process index method. The object of the research is the environmental footprint of wheeled tractors used for farming in Lithuania. Investigation showed that field works of tractors ac-counts the largest share of the total environmental footprint. Environmental footprint of tractors’ field works mainly depends from the type of fuel used which is directly dependent on the tractor's power and workload, consequently a change of fuel type, tractor type and work load can reduce en-vironmental footprint of tractors.

THE EVALUATION OF CEREAL FARMS USING ECOLOGICAL FOOTPRINT METHOD

Economic activities developed in the framework of sustainable development concept have to ensure balanced economic and technological development without weakening the social and natural environmental conditions. Environmental impact assessment using ecological footprint method helps to choose sustainable economic activities and technologies which are appropriate to sustainable development concept and has less impact to environment. This method is usually used as a public ecological and environmental educational tool and sometimes applied for creation of measures and programs for sustainable regional and economic development. The research problem is to determine whether the ecological footprint method is an appropriate tool to measure environmental impact of agricultural entities in accordance with sustainable development aspects. The paper aim is to evaluate the cereal farms using sustainable process index which is a member of ecological footprint method. The analysis was performed by analyzing the cereal farms which are growing wheat, rye and oats crops in Austria and Lithuania. The calculation was carried out using SPIonExcel software program. The results showed that the most significant environmental impacts arise from the use of fertilizers and the use of agricultural machinery (tractors and harvesters and the biggest share from the total ecological footprint goes to the pollution of air and water. The research also showed that if the ecological footprint method is used with a support service this can be a useful instrument for farmers showing how to improve farming from the ecological viewpoint and how to increase energy efficiency and reduce the use of primary resources.