High-rate activated sludge systems (HRAS) are gaining attention in Water Resource Recovery Facilities (WRRFs) seeking to become energy efficient wastewater treatment. One well-known HRAS system is the A-stage of the AB (adsorption−biooxidation) process which is common in Germany, Austria, and Netherlands. Recently, the Contact Stabilization (CS), which was a popular choice for many treatment facilities in the United States in the 1970s and 80s, has also been studied as a promising high-rate technology to harvest organic carbon from high and low-strength wastewater. Both technologies are innovative and energy efficient carbon capture technologies that can be easily retrofitted in existing infrastructure of WRRFs resulting in low capital cost. In these systems, the carbon diversion through biosorption process in HRAS systems minimize aeration cost and maximize energy production through methane gas potential in anaerobic digestion process. In addition to energy recovery, both technologies are able to divert significant amount of nitrogen and phosphorus through secondary waste activated sludge resulting in mainstream nutrient removal systems energy reduction. This paper discusses the selection of an appropriate HRAS technology for harvesting organic carbon from low-strength and high-strength domestic wastewater. The study focuses on A-stage, and high-rate CS as potential HRAS technology. Overall, this paper provides practical guidelines on the application of HRAS systems for high and low-strength wastewater treatment for energy recovery.

高速率活性污泥系统（HRAS）在寻求成为节能废水处理的水资源回收设施（WRRF）中得到了关注。一种著名的HRAS系统是AB（吸附-生物氧化）过程的A阶段，在德国，奥地利和荷兰很常见。最近，接触稳定化（CS）是1970年代和80年代在美国许多处理设施中流行的选择，也已被研究为一种从高强度和低强度废水中收集有机碳的有前途的高速率技术。 。两种技术都是创新的，高能效的碳捕集技术，可以很容易地在WRRF的现有基础设施中进行改造，从而降低了资本成本。在这些系统中 HRAS系统中通过生物吸附过程进行的碳转移可最大程度地减少曝气成本，并通过厌氧消化过程中的甲烷气势来最大化能源生产。除了能量回收外，这两种技术还能够通过二次废物活性污泥转移大量的氮和磷，从而导致主流的营养去除系统降低能耗。本文讨论了从低强度和高强度生活污水中收集有机碳的合适HRAS技术的选择。该研究集中于A级和高速率CS作为潜在的HRAS技术。总体而言，本文提供了有关HRAS系统在高强度和低强度废水处理中进行能量回收的应用的实用指南。