ABSTRACT
In its 30 years of existence, there are still many improvement possibilities in studies performing the life cycle assessment (LCA) of wastewater treatment plants (WWTPs). Hence, this paper aims to start a guideline development for LCA of urban WWTPs based on the information available in the scientific literature on the topic. The authors used the ProKnow-C systematic review methodology for paper selection and 111 studies were analyzed. The most significant points that can be improved are caused by missing essential information (e.g. functional unity and input data). Other important methodological aspects are covered: allocation process, functional unit choice, sensitivity analysis, and important fluxes to be considered. Many opportunities within the LCA of WWTPs were identified, such as optimization of WWTP operational aspects and resource recovery. Furthermore, LCA should be combined with other methodologies such as big data, data envelopment analysis, life cycle cost assessment, and social life cycle assessment. To achieve this potential, it is clear that the scientific and technical community needs to converge on a new protocol to ensure that LCA application becomes more reliable and transparent.
Subject(s)
Environment , Water Purification , Animals , Life Cycle StagesABSTRACT
Owing to the cost of destination and transportation of ornamental stone processing waste, many studies focused on the reuse and recycling of this product. However, there is a scarcity of articles addressing the environmental viability of the recycling of ornamental stone. In this context, this study comprehends a comparative life cycle assessment of ornamental stone processing waste and conventional materials: sand, clay and limestone filler. The modelling software used was SimaPro 8.3.0.0 with Ecoinvent 3.2 database, employing the ReCiPe H/H methodology for impact assessment. The results show that the recycling of ornamental stone processing waste is environmentally preferable, and the artificial drying alternatives, such as flash dryer and rotary dryer, have lower environmental impact than extracting and processing clay through atomisation methods and limestone filler production. The sensitivity analysis indicated that it is possible to transport the ornamental stone processing waste 37 km after processing, so it reaches the same environmental impact as sand extracted by dredging. On the other hand, an increase of 25% in the energy consumption incremented only 7% of the environmental impact owing to the Brazilian energy mix.