Vegetation effects on anammox spatial distribution and nitrogen removal in constructed wetlands treated with domestic sewage

Abstract

In this study, two horizontal subsurface-flow constructed wetlands (CWs) (planted and unplanted) were constructed and compared to investigate the effects of vegetation on nitrogen removal and anammox (anaerobic ammonium oxidation) spatial distribution and enrichment. Calamus (Acorus calamus L.), which has a large root system, was selected as the vegetation. Removal of total nitrogen from the planted wetland was much higher than that from the unplanted one. Radial oxygen loss from calamus provided the planted wetland with better oxygen restoration ability, benefitting ammonium removal in the CW, especially when anammox was inhibited under winter temperatures. Enrichment of anammox bacteria in planted wetlands was much greater than that in unplanted ones. The greatest enrichment of anammox bacteria occurred in the middle layer, which had a better anaerobic environment and moderate root system. The reduced rate of metabolism in plants during winter led to a sharp decrease in anammox bacteria copy numbers in the planted wetland. Under cold temperature, the degree of enrichment with anammox bacteria in the planted wetland was similar to or slightly superior to that in the unplanted wetland.

Remoção biológica de nitrogênio em sistemas alagados construídos enriquecidos com bactérias Anammox

“…Isto significa que o nitrito, que é intermediário de todos os mecanismos de remoção de nitrogênio, está sendo constantemente consumido e sugere uma alta diversidade microbiana. Em outros estudos um maior consumo de nitrito significa uma maior atividade Anammox (PAREDES; KUSCHK; KÖSER, 2007;TAO et al, 2012;LI, 2014b). Figura 15 -Cargas das espécies de nitrogênio no efluente de cada unidade experimental durante as três etapas do experimento.…”

“…Na atualidade vem se realizando vários estudos para avaliar os fatores que influenciam o desenvolvimento das bactérias oxidadoras de amônio dentro destes sistemas alagados (DONG; TAO;WANG, 2009;TAO et al, 2012;LI, 2014aLI, , 2014bZHU et al, 2011ZHU et al, , 2014. No Brasil, distintas pesquisas visam a aplicação do processo Anammox, em especial para efluentes com elevado teor de nitrogênio (KUNZ et al, 2013;SCHEEREN et al, 2011), outros autores estudam distintas estratégias nas condições de crescimento (AGNES et al, 2008), enriquecimento da biomassa (COSTA et al, 2014;DE ARAÚJO et al, 2010), e estratégias de partida para distintos reatores (CASAGRANDE et al, 2011).…”