Life cycle assessment for the land application of food processing wash-water and solid residuals.

A life cycle assessment (LCA) study was completed to understand the environmental impacts associated with the land application of wastes produced from rural food-processing operations for final disposal. The system boundaries for the two comprised scenarios included the storage of the produced non-agriculture source material (NASM), transportation to an applicable location, land application of the NASM, and the impacts of the final emissions to the soil and groundwater for a full year. The Tool for the Reduction and Assessment of Chemicals and Other Environmental Impacts (TRACI) v2.1 was selected as the impact assessment method. Furthermore, SimaPro 8.0.4.26 was the LCA model version that was used with all the databases included. Overall, the LCA study showed that the most significant environmental impacts associated with the disposal process resulted from carcinogenic and eutrophication emissions. The component that contributed the most to carcinogenic impacts was found to be from the material required to create the concrete storage tank. Additionally, eutrophication was identified to be a potential significant impact, if proper setback requirements are not followed for the NASM material. Results of the study look to inform stakeholders about the benefits and risks encountered from NASM disposal. PRACTITIONER POINTS: Life cycle assessment was completed on a representative NASM disposal system using land application. Concrete tank used for storage of NASM had the most significant impact in carcinogenic emissions. Eutrophication impacts were the second most significant impact behind carcinogenic emissions.

Relative sensitivity value (RSV): A metric for measuring input parameter influence in life cycle assessment modeling.

Life cycle assessment (LCA) is a commonly used tool to quantify life cycle environmental footprints of products. Uncertainty in LCA modeling, particularly from uncertainty in production practices (represented through input parameter arguments), can lead to incorrect conclusions and hamper decision-making. Characterization of uncertainty through stochastic means and sensitivity analysis is utilized in a small fraction of LCA case studies, and the majority of studies default to scenario analysis due to its lower barrier to implementation and its results are easier to interpret. In this article, we introduce a sensitivity metric, relative sensitivity value (RSV), which allows LCA practitioners to gauge the relative influence of production practices on life cycle impacts in multiple phases and impact categories. Relative sensitivity value bridges the gap between scenario analysis and global sensitivity analysis, and it allows an LCA practitioner to provide an easy-to-interpret metric for quantifying the degree to which incremental changes in production practices influences the life cycle environmental footprint. We present the methodology used to calculate RSV and provide programming code, which can be readily used by an LCA practitioner to calculate RSV for their LCA model. We demonstrate the usage of RSV through a livestock husbandry LCA case study, in which we show how RSV results may be presented and interpreted, and how conclusions regarding production practices may be drawn. Integr Environ Assess Manag 2023;19:547-555. © 2022 SETAC.

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.

Investigation of fugitive methane and gas collection efficiency in Halton landfill in Ontario, Canada.

Methane gas is one of the significant contributors to global warming. A large portion of methane emissions comes from landfills. Developing reliable measurement methods for methane emissions from landfill sites has become very important. In this paper, the surface emissions of methane gas are quantified using a portable probe having a flame ionization detector (FID), a method proven to be successful in landfill gas measurement. Surface methane emissions from two closed cells in the Halton landfill in Ontario, Canada, were measured using the FID method. By analyzing the emissions within the perimeter of the landfill, hotspots of gas leakage were identified. The closed cells in the Halton landfill are equipped with gas extraction system for flaring and energy recovery and a clay topsoil cover. Emission concentrations of fugitive methane were found to range from 0.1 to 63 ppm. The largest emissions were detected in locations next to the leachate extraction manholes and malfunctioning gas extraction wells. The landfill gas balance showed that the landfill gas recovery efficiency was 44%, resulting in an average amount of fugitive methane from the landfill of 6124 m3/day. The results of the study were used to determine the methane generation potential (Lo) for municipal solid waste to further calibrate the USEPA LandGEM model for Ontario landfills. The model was calibrated by actual methane emission measurement and recovery data. The calibrated Lo was found to be 70 m3/t, which is lower than the estimated values in previous studies.

Prediction of greenhouse gas emissions from Ontario's solid waste landfills using fuzzy logic based model.

In this study, multi-criteria assessment technique is used to predict the methane generation from large municipal solid waste landfills in Ontario, Canada. Although a number of properties determine the gas generation from landfills, these parameters are linked with empirical relationships making it difficult to generate precise information concerning gas production. Moreover, available landfill data involve sources of uncertainty and are mostly insufficient. To fully characterize the chemistry of reaction and predict gas generation volumes from landfills, a fuzzy-based model is proposed having seven input parameters. Parameters were identified in a linguistic form and linked by 19 IF-THEN statements. When compared to measured values, results of the fuzzy based model showed good prediction of landfill gas generation rates. Also, when compared to other first order decay and second order decay models like LandGEM, the fuzzy based model showed better results. When plotting the LandGEM and Fuzzy model values to the actual measured data, the fuzzy model resulted in a better fit to actual data than the LandGEM model with a coefficient of determination R2 of 0.951 for fuzzy model versus 0.804 for LandGEM model. The results show how multi-criteria assessment technique can be used in modelling of complicated processes that take place within the landfills and somehow accurately predicting the landfill gas generation rate under different operating conditions.

Vertical flow constructed wetlands for decentralized wastewater treatment in Jordan: Optimization of total nitrogen removal.

The baseline performance of two full-scale vertical flow (VF) constructed wetlands operating in the arid climate of Jordan is presented in this study, within the context of the Jordanian Standards for reuse of treated wastewater. One system was a recirculating VF wetland, and the other was a single-pass two-stage VF wetland. Operational modifications were made to each treatment system, with the aim of improving Total Nitrogen (TN) removal. For the recirculating VF system, attached-growth media was added to the recirculation tank to provide increased surface area for growth of denitrifying bacteria. The modification showed a small but significant improvement in TN removal (8 mg/L less than the baseline phase; p = 0.004). Statistical analysis showed that 30% and 4.5% of the increase in compliance with the TN limits (Class A and Class B/C, respectively) could be attributed to the modification. The two-stage VF wetland was modified with a step-feeding line that introduced carbon-rich raw wastewater to the intermediate pump shaft just upstream of the second-stage filter. The modification also resulted in a small but significant improvement in TN removal (13 mg/L less than the baseline phase; p = 0.005). The increase in compliance with the TN standard due to the modification was estimated at 20% and 22% for Class A and B/C, respectively. The simple operational modifications proved to be effective for improving total nitrogen removal in arid climate VF wetland systems.

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.