Environmental, Ecological, and Economic Benefits of Biofuel Production Using a Constructed Wetland: A Case Study in China

Abstract

Here we show a constructed wetland (CW), a viable alternative wastewater treatment system, be used to produce biofuels from biomass by using nitrogen contained in domestic wastewater. We summarize the potential biomass yield evaluated as cellulosic ethanol bioenergy production, and combine the life cycle analysis with a mass balance approach to estimate the energetic, environmental, and economic performance of a CW biofuel system. The results showed that the annual aboveground biomass yield of a CW in Zhoushan, Zhejiang Province, China, averaged 37,813 kg ha−1 year−1 as the by-product of treating waste N, which is about one order of magnitude larger than traditional biofuel production systems. The biomass yield in the Zhoushan CW system had life cycle environment benefits of 8.8 Mg (1 Mg = 106 g) CO2 equivalent ha−1 year−1 of greenhouse gas emission reduction. The CW in Zhoushan had a net energy gain of 249.9 GJ (1 GJ = 109 J) ha−1 year−1 while the wastewater treatment plant (WTP) consumes 7442.5 GJ ha−1 year−1. Moreover, the CW reduced greenhouse gas emissions to 2714 times less than that of the WTP. The CW also provided various ecosystem services, such as regional climate regulation and habitat conservation. We suggest that the potential use of a CW as biofuel production and carbon sequestration via nitrogen-negative input can be explored more widely in the future.

Life cycle cost assessment and economic analysis of a decentralized wastewater treatment to achieve water sustainability within the framework of circular economy

“…Furthermore, if planted, they can be aestheti-cally pleasing while promoting biodiversity, contributing to flood protection, and offering cooling effects (Dumax & Rozan, 2021). To strengthen the comparison with traditional wastewater plants, the fact that the greenhouse gas emissions (GHG) of a CW have proved to be 2714 times lower can be highlighted (Liu et al, 2019). Their high efficiency linked to important ecological benefits, make them green technology that promote a sustainable water supply (Cui et al, 2022).…”

Materials of biological origin and biofuels: Small environmental footprint and epigenetic impact (Review)

“…2G biofuels overcome the dilemma 'food vs. fuel' dilemma since they do not use edible crops, and thus do not negatively impact food production and quality. Additionally, certain 2G biofuels such as cellulosic ethanol from switchgrass and carbon-negative biofuels from low-input high-diversity grassland biomass require a lower agricultural input, i.e., less fertilizer, pesticide and energy (68). The main disadvantage of 2G biofuels is their production cost.…”

Analysis on Mode and Benefit of Resource Utilization of Rural Sewage in a Typical Chinese City

“…It can effectively address issues such as water scarcity, water pollution, and damage to water ecosystems while also improving the quality of rural ecological environments and contributing to the creation of beautiful countryside. The rural domestic sewage treatment work in Zhejiang Province is at the forefront of the country, and the construction of beautiful countryside has attracted nationwide attention [12]. Since 2003, Zhejiang Province has taken "demonstrating in a thousand villages and improving in ten thousand villages" as the main focus, implementing a series of rural domestic sewage treatment projects and accumulating rich practical experience in rural environmental governance [13].…”