Life-cycle assessment of full-scale membrane bioreactor and tertiary treatment technologies in the fruit processing industry.

A life-cycle assessment (LCA) study was completed to assess the environmental impacts of an on-site wastewater treatment system in the fresh-cut fruit processing industry consisting of a membrane bioreactor (MBR), followed by reverse osmosis (RO) and ultraviolet (UV) disinfection. The system boundaries comprised raw materials extraction and processing, transportation, construction, operation, and waste disposal. SimaPro 8.0.4.26 was used as the software tool, supported by two impact assessment methods (ReCiPe v1.11 and TRACI v2.1). Analysis showed that the treatment capacity of the MBR and tertiary technologies contributed the least damage to the ecosystem when compared with the other three scenarios and can provide water for reuse. Treating wastewater in municipal wastewater treatment plants (WWTPs) mitigated eutrophication like the MBR system but resulted in more environmental impacts from climate change and human health when compared with the on-site treatment system. Findings will be informative to stakeholders in the fresh-cut agri-food sector seeking input into selecting the appropriate treatment approach, with water reuse a goal. PRACTITIONER POINTS: Life-cycle analysis was completed on a fruit processing facility using MBR + RO + UV. On site treatment with MBR + RO UV provides least amount of environmental impact. Use of MBR + RO + UV treatment on fruit wastewater allows for water reuse. ReCiPe v1.11 and TRACI v2.1 give similar LCA results, with TRACI recommended for North American analysis.

Cradle-to-grave life cycle assessment (LCA) of low-impact-development (LID) technologies in southern Ontario.

A comparative cradle-to-grave life cycle assessment (LCA) of a low-impact-development (LID) parking lot test-site is performed to quantify the environmental costs of the manufacturing, construction, transportation, operation, maintenance and decommissioning of three bioretention cells and three permeable pavement systems (PPS) located in Mississauga, Ontario, as well as a hypothetical stormwater management pond. The LIDs' influent and effluent water quality and volume data is used to quantify the environmental benefits offered by the LIDs. Ecoinvent v3 LCA database is utilized to create an inventory of the materials and energy used during the life cycle of the LIDs. Using TRACI 2.1 impact assessment method, an LCA is conducted to simulate impacts on ten midpoint categories using a functional unit of "1 m2 of impervious area treated". It has been found that manufacturing of raw materials has the largest impact (∼50%) on ozone depletion, global warming, smog potential, acidification, carcinogenic emissions, respiratory effects and fossil fuel depletion. The LIDs offer a significant avoidance of eutrophication potential, non-carcinogenic emissions and ecotoxicity, which are all mostly associated with the water quality benefits offered by the LIDs. The bioretention impacts are ∼90% lower than the PPS' on a "per 1 m2 of impervious area treated" basis due to its larger impervious area treatment relative to its size compared to the PPS. The benefits offered by bioretention are significantly higher on "per 1 m2 LID area" basis (∼12x), but comparable on "per 1 m2 impervious area treated" basis. The impacts normalized by per-capita emissions in Canada in the year 2005 show that the negative impacts of the LIDs are insignificant compared to the benefits they provide. A comparison of the LIDs to a traditional pipe-and-pond infrastructure of an equivalent treatment capacity reveals that the cradle-to-grave impacts of LIDs are ∼20% lower compared to the detention pond's, and the benefits accrued by the LIDs are ∼300% higher compared to the detention pond, making a strong case for the selection of LIDs over traditional stormwater management practices.

Composting sewage sludge amended with different sawdust proportions and textures and organic waste of food industry--assessment of quality.

The quality of compost made from dewatered sewage sludge, sawdust (SD) and organic wastes of a potato-processing industry (OW), in terms of chemical and biological properties, was assessed. Mixtures of the sludge, SD and OW were composted for 57 days in insulated containers at two C:N ratios (approximately 30 : 1 and approximately 20 : 1) and SD textures (coarse- and fine-textured SD). The parameters monitored over this period were pH, electrical conductivity (EC), C:N ratio, CO2 evolution and two spectrophotometric ratios (Q2/6 and Q2/4). All the studied parameters were in general similarly influenced by initial C:N ratio and texture of SD except for EC, Q2/6 and Q2/4. At high C:N ratio of both textures, the EC of the final products increased but were less than those of low C:N ratio of both textures. Thus, final product can be used alone as growth medium without the need for grinding or blending with other materials. The spectrophotometric ratios (Q2/6 and Q2/4) dramatically decreased two weeks after composting and then slightly increased at the end of composting process. However, coarse-textured SD at the low C:N ratio and fine-textured SD at both C:N ratios resulted in lower Q2/6 and Q2/4 ratios, reflecting a better degree of aromatic condensation and organic matter humification. Considering these parameters, co-composting sludge with fine-textured SD and OW at high initial C:N ratio would represent the best compromise.