Conceptual system for sustainable and next-generation wastewater resource recovery facilities.

Shifting the concept of municipal wastewater treatment to recover resources is one of the key factors contributing to a sustainable society. A novel concept based on research is proposed to recover four main bio-based products from municipal wastewater while reaching the necessary regulatory standards. The main resource recovery units of the proposed system include upflow anaerobic sludge blanket reactor for the recovery of biogas (as product 1) from mainstream municipal wastewater after primary sedimentation. Sewage sludge is co-fermented with external organic waste such as food waste for volatile fatty acids (VFAs) production as precursors for other bio-based production. A portion of the VFA mixture (product 2) is used as carbon sources in the denitrification step of the nitrification/denitrification process as an alternative for nitrogen removal. The other alternative for nitrogen removal is the partial nitrification/anammx process. The VFA mixture is separated with nanofiltration/reverse osmosis membrane technology into low-carbon VFAs and high-carbon VFAs. Polyhydroxyalkanoate (as product 3) is produced from the low-carbon VFAs. Using membrane contactor-based processes and ion-exchange techniques, high-carbon VFAs are recovered as one-type VFA (pure VFA) and in ester forms (product 4). The nutrient-rich fermented and dewatered biosolid is applied as a fertilizer. The proposed units are seen as individual resource recovery systems as well as a concept of an integrated system. A qualitative environmental assessment of the proposed resource recovery units confirms the positive environmental impacts of the proposed system.

Life cycle assessment of a wind farm in Turkey.

The aim of this study is to investigate the environmental impacts of a full-scale wind farm using life cycle assessment methodology. The facility in question is an onshore wind farm located in Turkey with a total installed capacity of 47.5 MW consisting of 2.5 MW Nordex wind turbines. Hub height and rotor diameter of the wind turbines are 100 m. The system boundary is defined as material extraction, part production, construction, operation and maintenance and decommissioning phases of the wind farm. The functional unit is 1-kWh electricity produced. Environmental impacts are mainly generated by manufacturing and installation operations. Steel sheet usage in tower manufacturing is the main contributor to abiotic depletion of fossil resources, acidification, eutrophication, global warming and marine aquatic ecotoxicity potentials. Apart from ozone layer depletion, end-of-life phase decreases the environmental impacts due to metal recycling. Metal recycling ratio scenario results show that when the recycling ratio decreases from 90 to 20%; increases of 110%, 102%, 92% and 87% are observed in acidification, terrestrial ecotoxicity, marine aquatic ecotoxicity and global warming potentials, respectively. In the baseline, the main parts which are manufactured in Germany are transported by sea to Turkey. Transportation scenario involves shifting the manufacturing of main parts to Turkey then transporting these parts by trucks to the farm. This conversion causes increases of 31%, 35% and 27% in abiotic depletion of fossil resources, freshwater aquatic ecotoxicity and global warming potentials, respectively, while causing decreases of 11% and 4% in acidification and eutrophication potentials generated by transportation activities, respectively.

Life cycle assessment of a large water treatment plant in Turkey.

The objective of this study is to assess the environmental sustainability of a large water treatment plant through life cycle assessment (LCA) approach. This study is a pioneering one that explores the environmental impacts of a water treatment plant in Turkey by using the data collected from an actual plant. Decision makers of the treatment plant under investigation, operators of similar installations, and the scientific researchers that work on LCA of water treatment facilities are defined as the target audience. GaBi software is used for the LCA model, and CML 2001 method is adopted to calculate the results given per 1 m3 water ready to be distributed to the city. The plant serves about 2,600,000 people generating a maximum potable water flow rate of 400,000 m3/day. In the facility, 0.57 kWh of electricity is required to obtain 1 m3 of water. Of this total electricity consumption, 85% is allocated to inlet and outlet pumping stations. The results denote that the environmental impacts are dominated by electricity consumption that in turn depends on the energy source/s adopted. Sensitivity analysis on energy sources reveals the following outcomes: In case of using hard coal as energy source rather than grid mix, impacts are increased apart from freshwater aquatic ecotoxicity potential, ozone layer depletion potential, and abiotic depletion potential elements. Once solar panels are used instead of grid mix, values for all impact categories except abiotic depletion potential elements and human toxicity potential are lowered. The usage of wind turbines in place of grid mix results in 29 to 84% reductions in all investigated impact categories. The best option to decrease the environmental impacts is attained when energy is generated using wind turbines. As pumps having 90% efficiency replace the pumps with 60% efficiency, reductions ranging from 15 to 24% on all impact categories are obtained. The work performed for this study should be further pursued to obtain more representative inventory data for countries with scarce LCA studies.

Life cycle assessment of a printed circuit board manufacturing plant in Turkey.

The objective of this study is to investigate the environmental impacts of a printed circuit board (PCB) manufacturing plant through streamlined life cycle assessment approach. As a result, the most effective recommendations on minimizing the environmental impacts for the mentioned sector are revealed and first steps towards establishing a country specific database are taken. The whole PCB production consists of two consecutive stages: namely board fabrication followed by the manufacturing of PCB. Manufacturing of PCB contributes the highest shares to freshwater aquatic ecotoxicity potential (FAETP) and ozone layer depletion potential (ODP). Eighty-nine percent of FAETP is found to be generated from the manufacturing of PCB. Almost all of this contribution can be attributed to the disposal of copper containing wastewater treatment sludge from etching operations to incineration. On the other hand, PCB manufacturing has 73% share in total ODP. Within the manufacturing of PCB, as etching operations are found to be of importance for all the impact categories except eutrophication potential (EP), it is recommended to focus further studies on in-plant control of etching.