Nitrogen Treatment in Soil Beneath High-Flow and Low-Flow Onsite Wastewater Systems

Humphrey, Charles; Iverson, Guy; Underwood, William J.; Cary, Samuel S.; Skibiel, Caitlin; O’Driscoll, Michael A.

doi:10.1061/jswbay.0000888

Cited by 2 publications

(3 citation statements)

References 38 publications

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“…The presence of annamox may be due to high concentrations of organic carbon in the STU resulting in concurrent denitrification with heterotrophic Denitrifiers (Chamchoi et al, 2008). These results match previous studies which suggested that anammox was active within low flow sites and at 5-7.5 cm depths within the infiltrative surface (Cooper et al, 2016;Humphrey Jr et al, 2019). Increases in functional richness may help locate metabolic activities such as the presence of denitrifiers at the proximal position to the inlet at the SE-STU (Louca et al, 2018).…”

Section: Discussionsupporting

confidence: 86%

“…Most on-site wastewater treatment studies have focused on the system performance for the attenuation of hazardous contaminants from an environmental and public health perspective. These studies have generally focused on chemical parameters such as nutrients (different forms of nitrogen and phosphorus), bulk organics (BOD, COD, and TOC), and fecal indicator bacteria such as E. coli, enterococci, and bacteriophages as surrogates for human enteric viruses (van Cuyk and Siegrist, 2007;Gill et al, 2009;O'Luanaigh et al, 2012;Humphrey Jr et al, 2019). Increasingly, since the advance of microbiological culture-independent techniques in the early 1990s (Wagner et al, 2006), the performance of wastewater treatment systems has been coupled with the dynamics and stochastic modeling of the composition of microbial communities (Curtis and Sloan, 2005;Sanz and Köchling, 2007;Siezen and Galardini, 2008;Matar et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Spatial Variation of the Microbial Community Structure of On-Site Soil Treatment Units in a Temperate Climate, and the Role of Pre-treatment of Domestic Effluent in the Development of the Biomat Community

et al. 2022

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The growth of microbial mats or “biomats” has been identified as an essential component in the attenuation of pollutants within the soil treatment unit (STU) of conventional on-site wastewater treatment systems (OWTSs). This study aimed to characterize the microbial community which colonizes these niches and to determine the influence of the pre-treatment of raw-domestic wastewater on these communities. This was achieved through a detailed sampling campaign of two OWTSs. At each site, the STU areas were split whereby half received effluent directly from septic tanks, and half received more highly treated effluents from packaged aerobic treatment systems [a coconut husk media filter on one site, and a rotating biodisc contactor (RBC) on the other site]. Effluents from the RBC had a higher level of pre-treatment [~90% Total Organic Carbon (TOC) removal], compared to the media filter (~60% TOC removal). A total of 92 samples were obtained from both STU locations and characterized by 16S rRNA gene sequencing analysis. The fully treated effluent from the RBC resulted in greater microbial community richness and diversity within the STUs compared to the STUs receiving partially treated effluents. The microbial community structure found within the STU receiving fully treated effluents was significantly different from its septic tank, primary effluent counterpart. Moreover, the distance along each STU appears to have a greater impact on the community structure than the depth in each STU. Our findings highlight the spatial variability of diversity, Phylum- and Genus-level taxa, and functional groups within the STUs, which supports the assumption that specialized biomes develop around the application of effluents under different degrees of treatment and distance from the source. This research indicates that the application of pre-treated effluents infers significant changes in the microbial community structure, which in turn has important implications for the functionality of the STU, and consequently the potential risks to public health and the environment.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Spatial Variation of the Microbial Community Structure of On-Site Soil Treatment Units in a Temperate Climate, and the Role of Pre-treatment of Domestic Effluent in the Development of the Biomat Community

et al. 2022

View full text Add to dashboard Cite

show abstract

“…However, many onsite systems serve schools, hospitals, restaurants, and other businesses with high flows. Humphrey et al (2019) compared nitrogen transformations in low-flow systems with gravity distribution and high-flow systems with low-pressure pipe distribution and different soil types. The results provide insights into which flows and soil types should be targeted for implementation of advanced nitrogen removal systems.…”

Section: Soil-based Treatment Systemsmentioning

confidence: 99%