Combining algae cultivation and wastewater treatment for biofuel production is considered the feasible way for resource utilization. An updated comprehensive techno-economic analysis method that integrates resources availability into techno-economic analysis was employed to evaluate the wastewater-based algal biofuel production with the consideration of wastewater treatment improvement, greenhouse gases emissions, biofuel production costs, and coproduct utilization. An innovative approach consisting of microalgae cultivation on centrate wastewater, microalgae harvest through flocculation, solar drying of biomass, pyrolysis of biomass to bio-oil, and utilization of co-products, was analyzed and shown to yield profound positive results in comparison with others. The estimated break even selling price of biofuel ($2.23/gallon) is very close to the acceptable level. The approach would have better overall benefits and the internal rate of return would increase up to 18.7% if three critical components, namely cultivation, harvest, and downstream conversion could achieve breakthroughs.

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The construction of ecological civilization is an important requirement to realize high-quality development of the economy. Over recent decades, natural disasters, global warming, and other ecological problems have occurred frequently, and countries around the world are facing severe environmental challenges. Sustainable development is an effective way to solve these environmental threats, and environmental administrative penalties play a fundamental role in sustainable growth. So, we explore the response of external stakeholders to environmental administrative penalties from the perspective of auditors. The study examines whether environmental administrative penalties affect audit fees, the heterogeneity effects and the mechanisms. The research uses data of heavily polluting listed firms in China that have been revealed by the Institute of Public and Environmental Affairs (IPE). The findings show the following: (1) environmental administrative penalties can increase audit fees; (2) the effective internal control environment can weaken the positive relationship between firms’ environmental administrative penalties and audit fees, and the stronger regional environmental regulation can enhance the positive impact of firms’ environmental administrative penalties on audit fees; (3) further analysis shows that the impact of environmental administrative penalties on audit fees mainly comes from the “risk premium mechanism” rather than the “cost compensation mechanism”, and the response from audit fees can encourage firms to engage in green innovation activities. The above research conclusions provide a certain reference for auditors’ pricing decisions.

In the past 40 years, China's rapid industrialization has resulted in remarkable social progress and regional economic prosperity but also has caused problems, such as excessive resource consumption and environmental pollution. Ecological efficiency is an important indicator of whether economic efficiency and environmental efficiency are balanced. Exploring ecological efficiency is vital for achieving sustainable development, as technological innovation, industrial structure upgrading, and ecological efficiency are probably related. However, there has been little research on the relationships among them. In this study, we used the super‐efficiency slacks‐based model (SBM) involving undesirable output to calculate the ecological efficiency of 30 provinces in China from 2008 to 2017. We found that China's ecological efficiency has risen, fallen, then fluctuated, and that there were significant spatial differences. Then, we used 3 spatial econometric models for comparative analysis, which revealed that the independent effects of technological innovation on ecological efficiency was significant and negative; however, technological innovation demonstrated a strong positive effect in tandem with industrial structure upgrading, and industrial structure always had a positive effect on ecological efficiency. On this basis, we added the cross‐item of technological innovation, and industrial‐structure upgrades had a significant and positive impact on ecological efficiency, which was significantly greater than the independent effect of technological innovation and industrial‐structure upgrades. To explore the mechanism of industrial‐structure upgrading and technological innovation on regional ecological efficiency, we set the first 2 as threshold variables. We found that there is in fact a threshold effect of technological innovation and industrial‐structure upgrading on ecological efficiency due to the mismatch of periods. These results provide a theoretical rationale for China to formulate strategies to improve ecological efficiency. Integr Environ Assess Manag 2021;17:852–865. © 2020 SETAC

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