Sustainable Blue Foods from Rice-Animal Coculture Systems

Global interest grows in blue foods as part of sustainable diets, but little is known about the potential and environmental performance of blue foods from rice-animal coculture systems. Here, we compiled a large experimental database and conducted a comprehensive life cycle assessment to estimate the impacts of scaling up rice-fish and rice-crayfish systems in China. We find that a large amount of protein can be produced from the coculture systems, equivalent to ∼20% of freshwater aquaculture and ∼70% of marine wild capture projected in 2030. Because of the ecological benefits created by the symbiotic relationships, cocultured fish and crayfish are estimated to be carbon-negative (-9.8 and -4.7 kg of CO2e per 100 g of protein, respectively). When promoted at scale to displace red meat, they can save up to ∼98 million tons of greenhouse gases and up to ∼13 million hectares of farmland, equivalent to ∼44% of China's total rice acreage. These results suggest that rice-animal coculture systems can be an important source of blue foods and contribute to a sustainable dietary shift, while reducing the environmental footprints of rice production. To harvest these benefits, robust policy supports are required to guide the sustainable development of coculture systems and promote healthy and sustainable dietary change.

Case study of aerobic granular sludge and activated sludge-Energy usage, footprint, and nutrient removal

This study demonstrates a comparison of energy usage, land footprint, and volumetric requirements of municipal wastewater treatment with aerobic granular sludge (AGS) and conventional activated sludge (CAS) at a full-scale wastewater treatment plant characterized by large fluctuations in nutrient loadings and temperature. The concentration of organic matter in the influent to the AGS was increased by means of hydrolysis and bypassing the pre-settler. Both treatment lines produced effluent concentrations below 5 mg BOD7 L-1 , 10 mg TN L-1 , and 1 mg TP L-1 , by enhanced biological nitrogen- and phosphorus removal. In this case study, the averages of volumetric energy usage over 1 year were 0.22 ± 0.08 and 0.26 ± 0.07 kWh m-3 for the AGS and CAS, respectively. A larger difference was observed for the energy usage per reduced population equivalents (P.E.), which was on average 0.19 ± 0.08 kWh P.E.-1 for the AGS and 0.30 ± 0.08 kWh P.E.-1 for the CAS. However, both processes had the potential for decreased energy usage. Over 1 year, both processes showed similar fluctuations in energy usage, related to variations in loading, temperature, and DO. The AGS had a lower specific area, 0.3 m2  m-3 d-1 , compared to 0.6 m2  m-3 d-1 of the CAS, and also a lower specific volume, 1.3 m3  m-3 d-1 compared to 2.0 m3  m-3 d-1 . This study confirms that AGS at full-scale can be compact and still have comparable energy usage as CAS. PRACTITIONER POINTS: Full-scale case study comparison of aerobic granular sludge (AGS) and conventional activated sludge (CAS), operated in parallel. AGS had 50 % lower footprint compared to CAS. Energy usage was lower in the AGS, but both processes had potential to improve the energy usage efficiency. Both processes showed low average effluent concentrations.

Essential Oils Land Footprint: A Sustainability Meta-Analysis of Essential Oils Biopesticides

BACKGROUND

Essential oils (EO) are considered as safe and sustainable alternatives of synthetically produced industrial raw materials. While EO are renewable resources their production is traced to land use, therefore employing nonrenewable resources. This fact is often neglected during market up-take, which is established on EO bioactivity efficacy.

METHODS

Present study is aiming this knowledge gap through an innovative algorithm that employs spatial yield, bioactivity performance and fundamental experimentation details to calculate the land footprint. The proposed methodology is tested upon a concise pool of 54 EO, of which 9 originate from 8 culinary herbs, 27 from 3 juniper taxa, and 18 from 6 Citrus sp. crops. All 54 EO were subjected to repellent evaluation and 44 of them also to larvicidal, encompassing in the protocol both choice and no-choice bioassays.

RESULTS

Based on these bioprospecting data the proposed protocol effectively calculated the land footprint for all EO and bioassays. The repellent land footprint indicated as more sustainable the EO from savory, oregano, tarhan, thyme, Greek sage, and juniper berries for which each application corresponds to 3.97, 4.74, 7.33, 7.66, 8.01 and 8.32 m2 respectively. The larvicidal assessment suggested as more sustainable the EOs from savory, oregano, fennel, thyme, tarhan, and rue with land footprints of 1.56, 1.79, 2.16, 2.89, 3.70 and 4.30 m2 respectively.

CONCLUSIONS

The proposed protocol managed to calculate the land footprint for each EO and bioactivity and indicated the more sustainable EO per use based on widely available bioprospecting data.

Trading Land: A Review of Approaches to Accounting for Upstream Land Requirements of Traded Products

Land use is recognized as a pervasive driver of environmental impacts, including climate change and biodiversity loss. Global trade leads to "telecoupling" between the land use of production and the consumption of biomass-based goods and services. Telecoupling is captured by accounts of the upstream land requirements associated with traded products, also commonly referred to as land footprints. These accounts face challenges in two main areas: (1) the allocation of land to products traded and consumed and (2) the metrics to account for differences in land quality and land-use intensity. For two main families of accounting approaches (biophysical, factor-based and environmentally extended input-output analysis), this review discusses conceptual differences and compares results for land footprints. Biophysical approaches are able to capture a large number of products and different land uses, but suffer from a truncation problem. Economic approaches solve the truncation problem, but are hampered by the limited disaggregation of sectors and products. In light of the conceptual differences, the overall similarity of results generated by both types of approaches is remarkable. Diametrically opposed results for some of the world's largest producers and consumers of biomass-based products, however, make interpretation difficult. This review aims to provide clarity on some of the underlying conceptual issues of accounting for land footprints.