Durability and performance of loofah sponge as carrier for wastewater treatment with high ammonium

Abstract

Loofah sponge (LS) was used as carrier for high ammonia wastewater treatment with a sequencing batch biofilm reactor (SBBR), aimed at evaluating its nitrogen removal performance and durability to changeable pH and microbial corrosion. The results indicate that the average removal for COD, ${\text{NH}}_4^{+}$ -N and total nitrogen (TN) accounted for more than 80%, 90%, and 70%, respectively, in 203 days. After SBBR operation for 108 days, the average weight loss of the loofah sponge was 49.1%. Yet, the main structure of utilized loofah sponge remained unaffected (proved by scanning electron microscopy). Moreover, based on attenuated total reflection-infrared spectroscopy (ATR-IR) and X-ray diffraction (XRD) measurements, cellulose, and hemicelluloses in the loofah sponge were reduced significantly obviously causing the proportion of lignin to increase. During the 108th to 203 days, the removal efficiencies of COD (81.6 ± 7.05%), ${\text{NH}}_4^{+}$ -N (79.4 ± 8.82%), and TN (79.9 ± 2.85%) remained at a high level. PRACTITIONER POINTS: Loofah sponge had good durability to high ammonia and changeable pH. Lignin was the protective material of loofah sponge for resisting pH fluctuation and microbial corrosion. SBBR maintained a steady nitrogen removal performance with a low COD/N ratio.

Keywords: carrier; durability; high ammonia; loofah sponge; wastewater treatment.