High Rate Nitrogen Removal in an Alum Sludge-Based Intermittent Aeration Constructed Wetland

Abstract

A new development on treatment wetland technology for the purpose of achieving high rate nitrogen removal from high strength wastewater has been made in this study. The laboratory scale alum sludge-based intermittent aeration constructed wetland (AlS-IACW) was integrated with predenitrification, intermittent aeration, and step-feeding strategies. Results obtained from 280 days of operation have demonstrated extraordinary nitrogen removal performance with mean total nitrogen (TN) removal efficiency of 90% under high N loading rate (NLR) of 46.7 g N m–2 d–1. This performance was a substantial improvement compared to the reported TN removal performance in literature. Most significantly, partial nitrification and simultaneous nitrification denitrification (SND) via nitrite was found to be the main nitrogen conversion pathways in the AlS-IACW system under high dissolved oxygen concentrations (3–6 mg L–1) without specific control. SND under high dissolved oxygen (DO) brings high nitrogen conversion rates. Partial nitrification and SND via nitrite can significantly reduce the demand for organic carbon compared with full nitrification and denitrification via nitrate (up to 40%). Overall, these mechanisms allow the system to maintaining efficient and high rate TN removal even under carbon limiting conditions.

Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Optimization of wetland substrates and hydraulic loading

“…Currently, it has been proven that CWs can serve as a cost-effective and promising alternative to conventional wastewater treatment methods for removing or reducing a wide variety of contaminant such as nitrogen, phosphorous, and chemical oxygen demand (COD) (Lin et al, 2002;Hu et al, 2012b;Li et al, 2013;Wang et al, 2013), and even antibiotics (Hijosa-Valsero et al, 2011;Liu et al, 2013b;Berglund et al, 2014;Chen et al, 2014) and ARGs (Liu et al, 2013b;Chen et al, 2014). However, most of the previous studies focus on the single removal of nitrogen, or phosphorous, or antibiotics by CWs.…”

Removal of antibiotics and antibiotic resistance genes from domestic sewage by constructed wetlands: Effect of flow configuration and plant species

“…Previous studies demonstrated that CWs are capable of removing a majority of environmental pollutants including nitrogen, phosphorous, chemical oxygen demand (COD) (Lin et al, 2002a;Hu et al, 2012;Li et al, 2013;Wang et al, 2013), and emerging contaminants such as antibiotics (Hijosa-Valsero et al, 2011;Berglund et al, 2014;Chen et al, 2015) and ARGs Chen et al, 2015). Their performance depends on the design parameters such as plant species, flow types, substrates, hydraulic loading rates, hydraulic retention time and applied pollutants loadings (Hijosa-Valsero et al, 2010;Hijosa-Valsero et al, 2011;Saeed and Sun, 2012;Weerakoon et al, 2013;Wu et al, 2014;Wu et al, 2015).…”

Preliminary investigation of constructed wetland incorporating microbial fuel cell: Batch and continuous flow trials

“…Recent developments of CW technology allows it to be able to treat high strength wastewater with robust organic and nutrients removal, with minimal construction and operating costs, by employing alum sludge as the main substrate and operating with a tidal flow strategy [13][14][15][16]. In order to function efficiently the anode compartment of a MFC must remain anaerobic while freely available oxygen at the cathode will combine with protons and electrons to complete the circuit.…”