Nitrogen and Phosphorus Removal Efficiency and Denitrification Kinetics of Different Substrates in Constructed Wetland

Abstract

Constructed wetlands (CWs) are generally used for wastewater treatment and removing nitrogen and phosphorus. However, the treatment efficiency of CWs is limited due to the poor performance of various substrates. To find appropriate substrates of CWs for micro-polluted water treatment, zeolite, quartz sand, bio-ceramsite, porous filter, and palygorskite self-assembled composite material (PSM) were used as filtering media to treat slightly polluted water with the aid of autotrophic denitrifying bacteria. PSM exhibited the most remarkable nitrogen and phosphorus removal performance among these substrates. The average removal efficiencies of ammonia nitrogen, total nitrogen, and total phosphorus of PSM were 66.4%, 58.1%, and 85%, respectively. First-order continuous stirred-tank reactor (first-order-CSTR) and Monod continuous stirred-tank reactor (Monod-CSTR) models were established to investigate the kinetic behavior of denitrification nitrogen removal processes using different substrates. Monod-CSTR model was proven to be an accurate model that could simulate nitrate nitrogen removal performance in vertical flow constructed wetland (VFCWs). Moreover, PSM demonstrated significant pollutant removal capacity with the kinetics coefficient of 2.0021 g/m2 d. Hence, PSM can be considered as a promising new type of substrate for micro-polluted wastewater treatment, and Monod-CSTR model can be employed to simulate denitrification processes.

Seasonal impact of constructed wetlands on nitrogen and phosphorus in sediments of flood control lakes with pollution assessment

“…Given the pivotal role of wetlands in enhancing water quality, the systematic exploration of mechanisms governing N and P removal within artificial wetlands has emerged as an imperative research endeavor (Zeng et al., 2022). In recent years, numerous studies have elucidated the mechanisms responsible for nutrient retention within wetland ecosystems, as exemplified by the following examples: (1) Wetland plants uptake P from sediments and overlying water through their roots (C. Wang et al., 2018); (2) Microbial communities remove N mediated by nitrification and denitrification pathways (Walton et al., 2020; Z. Chen et al., 2022); (3) Phosphoric acid ions in water are adsorbed to the surface of Fe 3+ and Al 3+ ions in wetland substrate primarily through ligand exchange (W. Zhang et al., 2017); (4) Algal growth increases alkaline phosphatase activity and promotes P release (Ma et al., 2021).…”

Testing Zeolite and Palygorskite as a Potential Medium for Ammonium Recovery and Brewery Wastewater Treatment

“…Similarly, palygorskite is a significant industrial mineral that is closely associated with absorption processes [30]. This mineral exhibits removal rates of 90% for N and 85% for P [31].…”

Application of Modified Biochar in the Treatment of Pesticide Wastewater by Constructed Wetland

“…Biochar has attracted attention due to its high carbon content, large specific surface area, developed porosity, various surface functional groups, stable structure [12], and performance in strengthening nitrogen and phosphorus removal in sewage [13]. This paper aimed to modify the biochar to improve its adsorption performance for the herbicide atrazine and apply the modified biochar to the constructed wetland.…”