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Published on: January 2, 2014
Small-Portion Replacement with MnOx Media Promotes Biofilm Development, Leading to Rapid Biological Maturation and
Xuyang Liu1,2, Yuliang Su3, Huidong Shen3
1Institute of Environmental and Municipal Engineering, North China University of Water Resources and Electric Power, Zhengzhou 450045, China.
Abstract:
Stringent control of Mn is critical for drinking water safety. However, conventional rapid sand filters exhibit slow biological maturation for Mn(II) removal, limiting their performance in engineered Mn(II) removal. This study examined the effectiveness of partially replacing sand with natural manganese ore (NMO) to enhance Mn(II) removal and elucidated the underlying mechanisms. The results showed that replacing only 1/8 of sand with NMO enabled consistently effective Mn(II) removal (residual <5 μg/L) from start-up through long-term operation, even under stressful conditions; its performance was comparable to columns packed with 100% NMO. In 1/8 NMO columns, early Mn(II) removal driven by MnOx-mediated chemical processes rapidly diminished, after which MnOx-enhanced biological processes promptly took over. Compared with sand columns, 1/8 NMO columns biologically matured nearly 100 days earlier, and biomass on the rough, porous MnOx surface was 1-2 orders of magnitude higher than that on sand. Although NMO partly altered microbial communities, the relative abundance of Mn(II)-oxidizing bacteria did not increase; the larger absolute biofilm biomass primarily drove sustained efficient Mn(II) removal. These findings highlighted the important but previously overlooked role of MnOx in promoting biofilm accumulation and accelerating the maturation of biological Mn(II) removal systems and provided a practical and cost-effective upgrade for conventional sand filtration.
Insights
Partially replacing sand with natural manganese ore (NMO) significantly enhances manganese (Mn(II)) removal in drinking water filters. This upgrade accelerates biological maturation, ensuring safe water by improving filter performance.
Area of Science:
- Environmental Engineering
- Water Treatment Technologies
- Microbial Water Quality
Background:
- Stringent manganese (Mn) control is vital for drinking water safety.
- Conventional rapid sand filters mature slowly for effective Mn(II) removal.
- Engineered solutions are needed to improve Mn(II) removal efficiency.
Purpose of the Study:
- To evaluate the effectiveness of substituting sand with natural manganese ore (NMO) for enhanced Mn(II) removal.
- To understand the mechanisms behind improved Mn(II) removal in NMO-amended filters.
- To assess the impact of NMO on filter biological maturation and microbial communities.
Main Methods:
- Experimental setup using sand columns partially replaced with NMO.
- Monitoring Mn(II) removal efficiency from start-up to long-term operation.
- Analysis of biofilm accumulation and microbial community structure.
Main Results:
- Replacing 1/8 of sand with NMO achieved consistent Mn(II) removal (<5 μg/L), comparable to 100% NMO.
- NMO-amended filters matured biologically almost 100 days earlier than sand-only filters.
- Higher biomass on NMO surfaces, rather than increased specific bacteria, drove efficient Mn(II) removal.
Conclusions:
- Partial NMO replacement is a cost-effective upgrade for rapid sand filters.
- MnOₓ surfaces significantly promote biofilm accumulation, accelerating biological maturation.
- This approach offers a practical solution for improving drinking water Mn(II) removal.
