Elucidating Novel Algal-Sludge Granules for Wastewater Treatment and Biomethane Feedstock Generation

美国大多数城市目前使用活性污泥法处理废水。该工艺实现了二级处理，但能耗高，主要是由于有机物和营养物处理需要曝气。近年来，人们对藻类废水处理的兴趣越来越大，因为它能够通过光合藻类和细菌的共生生长来处理不加气的废水，并产生生物燃料原料。尽管有这些好处，但由于缺乏微藻生物絮凝，导致生物质与水分离困难，并且无法控制废水环境中的藻类，阻碍了废水处理藻类工艺的发展。本研究的目的是阐明微藻和细菌的生物造粒，产生新的藻泥颗粒。这些颗粒是由微藻和细菌组成的大而致密的球形生物聚集体。初步研究发现，藻泥颗粒可在废水环境中自然形成，并可用于流式生物反应器处理废水。由于物理特性，颗粒很容易从水中分离出来，克服了藻类过程的主要挑战之一。此外，同一颗粒生物质中藻类和细菌的共生有利于废水和营养物处理藻类过程的工程化。为了揭示微藻和细菌的生物造粒机制，本研究将采用一系列间歇式和流式反应器研究，并研究光、温度和生长速率对藻-细菌造粒的影响。为了确定藻泥颗粒的微生物性质和表征其理化性质，研究人员将通过本研究对生物颗粒进行遗传、微观和理化分析。该项目还将使用微传感器方法来记录颗粒中关键代谢化学物质的运输，从而研究颗粒的微生物活性和功能以及它们与废水处理性能的联系。最后，本研究将对收获的生物颗粒进行厌氧消化研究，以研究其命运、消化率和厌氧消化的甲烷生物能源产量，特别是与其他原料（如污水污泥和纯藻类生物质培养物）进行比较。本研究的贡献将揭示新型藻类污泥颗粒及其在实际废水处理背景下的生长背后的基础科学。该研究具有重要意义，因为藻类和细菌的生物颗粒将导致可控和有效的藻类废水处理工艺。此外，藻类和细菌的共生生长将导致废水处理产生生物原料的有意义的生物质产量。总的来说，这项研究的结果不仅将推动废水处理领域的发展，而且还将通过减少废水处理过程中的能源消耗，增加通过厌氧消化以生物能源原料和生物甲烷的形式回收废水化学能的机会，对社会产生实质性的广泛影响和效益。

CBET - 1335816Chul ParkUniversity of Massachusetts AmherstMost municipalities in the US currently use the activated sludge process to treat wastewater. The process achieves secondary treatment but is energy intensive, mainly due to its need of aeration for organic matter and nutrient treatment. Interest in algae-based wastewater treatment has increased in recent years because of its ability to treat wastewater without aeration through the symbiotic growth of photosynthetic algae and bacteria and generate biofuel feedstock. Despite these benefits, the lack of microalgae bioflocculation, which accounts for the difficulty in separating biomass from water, and an inability to control algal species in the wastewater environment have hindered the development of algae processes for wastewater treatment. The objective of this research is to elucidate biogranulation of microalgae and bacteria that yields novel algal-sludge granules. These granules are large, dense, and spherical bioaggregates composed of both microalgae and bacteria. Preliminary research has found that algal-sludge granules can be naturally formed in the wastewater environment and be used for treating wastewater in a flow-through bioreactor. Due to physical characteristics, granules readily separate out from water, overcoming one of the major challenges of algae processes. In addition, symbiosis of algae and bacteria within the same granular biomass facilitates the engineering of an algae process for wastewater and nutrient treatment. To unveil the mechanisms of biogranulation of microalgae and bacteria this research will employ a series of batch and a flow-through reactor studies and investigate the effect of light, temperature, and growth rates on algal-bacterial granulation. To determine the microbiological nature and characterize physiochemical properties of algal-sludge granules, the investigators will conduct genetic, microscopic, and physicochemical analyses on the biogranules through this research. The project will also use a compliment of microsensor approaches to document the transport of key metabolic chemicals across the granules, thus studying microbial activity and function of the granules and their link to wastewater treatment performances. Finally, the research will conduct anaerobic digestion study on harvested biogranules to investigate its fate, digestibility, and methane bioenergy yield by anaerobic digestion, especially compared to other feedstock, such as sewage sludge and pure cultures of algal biomass.The contribution of this research will reveal the fundamental science behind the development of novel algal-sludge granules and their growth in the context of real wastewater treatment. This research is significant, because biogranules of algae and bacteria will result in a controllable and effective algae-based wastewater treatment process. Additionally, the symbiotic growth of algae and bacteria will lead to meaningful biomass yield for biofeedstock generation from wastewater treatment. Collectively, the outcome of this research will not only advance the field of wastewater treatment, it will also have a substantially broad impact and benefit to society by reducing the energy consumed during wastewater treatment and increasing opportunity to recover chemical energy of wastewater in the form of bioenergy feedstock and biomethane through its anaerobic digestion.