Resumen de Performance and microbial diversity of denitrifying biofilms on polyurethane foam coupled with various solid carbon sources for nitrate-rich water purification

Shuangyu Pi, Jingya Sun, Lijuan Feng, Jiaheng Zhou

• This study investigated the performance and microbial communities of denitrifying biofilms on polyurethane foam coupled with various solid carbon sources of acid- and alkali-pretreated rice straw and rice husk. Results showed that acid and alkali-pretreated rice straw both had higher TOC release rates (0.041–0.685 mg g−1 day−1) than those of rice husk (0.019–0.160 mg g−1 day−1) over a month, while acid pretreatment of rice husk and rice straw had a much higher organics release rate than that of alkali pretreatment and non-pretreatment, respectively. Acid-pretreated rice straw achieved the most efficient TN removal performance (82.06 ± 3.65%) with the lower occurrences of NH4+-N during denitrification than that of alkali-pretreated rice straw (80.05 ± 4.12%) over more than a month operation. However, alkali pretreatment of rice husk demonstrated much more significantly efficient TN removal efficiency (80.39 ± 2.1%) than did acid pretreatment (69.59 ± 13.43%). MiSeq sequencing analysis showed that the four biofilm samples attached on polyurethane foam with the addition of pretreated rice straw or rice husk had a range of 13–15 differentially abundant phylum and 81–123 differentially abundant genera in comparison with biofilm without extra solid carbon sources, and a higher TN removal efficiency demonstrated more types of differentially abundant genera.