Aerobic granular sludge (AGS) needs a long start-up time and always shows unstable performance when it is used to treat low-strength wastewater. In this study, a rapid static feeding combined with Fe addition as a novel strategy was employed to improve the formation and stability of AGS in treating low-strength wastewater. Fe-AGS was formed within only 7 days and showed favorable pollutant removal capability and settling performance. The ammonia nitrogen (NH-N) and chemical oxygen demand (COD) concentration in the effluent were lower than 5 mg/L and 50 mg/L after day 23, respectively. The sludge volume index (SVI) and mixed liquid suspended solids (MLSS) was 37 mL/g and 2.15 g/L on day 50, respectively. Rapid static feeding can accelerate granules formation by promoting the growth of heterotrophic bacteria, but the granules are unstable due to filamentous bacteria overgrowth. Fe addition can inhibit the growth of filamentous bacteria and promote the aggregation of functional bacteria (eg. Nitrosomonas, Nitrolancea, Paracoccus, Diaphorobacter) by enhancing the secretion of extracellular polymeric substances (EPS). This study provides a new way for AGS application in low-strength wastewater treatment.
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http://dx.doi.org/10.1016/j.envres.2023.117770 | DOI Listing |
J Environ Manage
February 2025
School of Artificial Intelligence, Xidian University, No. 2 South Taibai Road, Xi'an, Shaanxi, 710071, China.
In the process of partial nitrification and anaerobic ammonia oxidation (anammox) for nitrogen removal, the process offers simple metabolic pathways, low operating costs, and high nitrogenous loading rates. However, since the partial nitrification-anammox (PN-anammox) process combines partial nitrification and anammox reactions within the same reactor, strict control of dissolved oxygen (DO) is essential. Additionally, assessing treatment performance through chemical measurement involves time lag, making it challenging to recover the biological process when issue arise, especially in the PN-anammox process, where strict DO control and the sensitivity of anammox bacteria to conditions and substrates demand timely intervention.
View Article and Find Full Text PDFWater Res
March 2025
Department of Biological Systems Engineering, Virginia Tech, Blacksburg, VA, USA. Electronic address:
Bioresour Technol
February 2025
Key Laboratory of Microbial Technology for Industrial Pollution Control of Zhejiang Province, College of Environment, Zhejiang University of Technology, Hangzhou 310014, China. Electronic address:
Municipal wastewater treatment plants in China face significant challenges in effectively removing pollutants from low-strength wastewater with a low carbon-to-nitrogen (COD/N) ratio. This study proposes a novel approach incorporating porous polymers embedded with iron-carbon (PP-IC) into an activated sludge system to enhance treatment. The PP-IC accelerated the formation of densified activated sludge (DAS), characterized by small particle sizes (<200 μm), excellent settleability (sludge volume index: 61 mL/g), and improved pollutant removal efficiency, with total nitrogen and total phosphorus removal rates increasing by 14.
View Article and Find Full Text PDFBioresour Technol
January 2025
School of Biosciences and Bioengineering, Indian Institute of Technology Mandi, Kamand 175075, India. Electronic address:
Bioresour Technol
December 2024
National Engineering Laboratory for Advanced Municipal Wastewater Treatment and Reuse Technology, Engineering Research Center of Beijing, Beijing University of Technology, Beijing 100124, PR China. Electronic address:
Conditions conducive to aerobic granular sludge (AGS) growth and maintenance are very difficult to realize in continuous-flow biological treatment processes. This study conducted a continuous-flow self-circulating up-flow granular sludge fluidized bed (Zier process) treating real urban wastewater approximately one year. The substantial self-circulating multiple times (R, 8-15 times) and up-flow velocity (8-15 m/h) generated by aeration, the only power equipment in Zier process, facilitated pollutant removal, particle granulation and stabilization.
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