Abstract：
A paradigm shift is needed in wastewater treatment plants (WWTPs) to progress from traditional pollutant removal to resource recovery. However, whether this transformation produces overall environmental benefits will depend on the efficient and sustainable use of resources by emerging technologies. Given that many of these technologies are still being tested at the pilot scale, there is a lack of environmental assessments quantifying their impacts and benefits. In particular, an integrated approach to energy and nutrient recovery can elucidate the potential configurations for WWTPs. In this study, we conduct a life cycle assessment (LCA) of emergent wastewater treatment technologies aimed at increasing resource circularity in WWTPs. We focus on increasing energy self-sufficiency through biogas upgrades and a more radical circular approach aimed at nutrient recovery. Based on a case-study WWTP, we compare its current configuration with (1) implementing autotrophic nitrogen removal in the mainstream and deriving most of the organic matter for biogas production, which increases the quality and quantity of biogas available for energy production; (2) implementing struvite recovery through enhanced biological phosphorus removal (EBPR) as a radical approach to phosphorus management, offering an alternative to mineral fertilizer; and (3) a combination of both approaches. The results show that incremental changes in biogas production are insufficient for compensating for the environmental investment in infrastructure, although autotrophic nitrogen removal is beneficial for increasing the quality of the effluent. Combined phosphorus and energy recovery reduce the environmental impacts from the avoided use of fertilizers and phosphorus and the nitrogen release into water bodies. An integrated approach to resource management in WWTPs is thus desirable and creates new opportunities toward the implementation of circular strategies with low environmental impact in cities.
摘要：
废水处理厂（WWTP）需要进行范式转变，以从传统的污染物去除到资源回收。然而,这种转变是否产生整体环境效益将取决于新兴技术对资源的有效和可持续利用。鉴于这些技术中的许多仍在试点规模的测试中，缺乏量化其影响和收益的环境评估。特别是,能量和养分回收的综合方法可以阐明污水处理厂的潜在配置。在这项研究中,我们对新兴污水处理技术进行了生命周期评估（LCA），旨在提高污水处理厂的资源循环性。我们专注于通过沼气升级和旨在营养恢复的更激进的循环方法来提高能源自给自足。基于污水处理厂的案例研究，我们将其当前配置与（1）在主流中实施自养脱氮并获得大部分有机物用于沼气生产，这增加了可用于能源生产的沼气的质量和数量；（2）通过增强的生物除磷（EBPR）作为磷管理的激进方法来实施鸟粪石回收，提供矿物肥料的替代品；(3)两种方法的结合。结果表明，沼气产量的增量变化不足以补偿基础设施的环境投资，虽然自养脱氮有利于提高出水水质。磷和能量回收的结合减少了避免使用肥料和磷以及氮释放到水体中对环境的影响。因此，在WWTP中采用综合的资源管理方法是可取的，并为在城市中实施对环境影响较小的循环战略创造了新的机会。
