Denitrification of drinking water using Saccharum spontaneum L. as a natural organic solid substrate

Abstract

There is a global concern regarding the increasing pollution of natural water bodies by nitrate as a result of anthropogenic activities. To address this situation, natural organic solid substrates (NOSS) have been investigated as carbon sources in denitrification. Despite advances in this field, a lack of knowledge about the kinetics involved in the denitrification processes using NOSS still exists. For this reason, we have studied denitrification using Saccharum spontaneum L. (S. spontaneum) as NOSS to better understand these kinetic processes. This paper presents experimental results obtained for the release of organic carbon from S. spontaneum, and for its use by denitrifying bacteria. Laboratory tests were developed under anoxic conditions in batch reactors. Our results showed that the kinetics of release of organic carbon from the S. spontaneum was first order (0.08 d À1 ). Furthermore, the maximum rate of utilization of substrate (5.61 mg N-NO 3 À mgVSS À1 day À1 ) and the denitrification rate (327 mg N-NO 3 À L À1 d À1 ) were high (VSS ¼ volatile suspended solids). We demonstrated that it is possible to obtain high yields of denitrification using organic carbon released from S. spontaneum. This study improves the knowledge on the use of NOSS, as alternative sources of carbon for denitrification.

Evaluation of Natural Materials as Exogenous Carbon Sources for Biological Treatment of Low Carbon-to-Nitrogen Wastewater

“…After 20 days, additional COD was still released but at a slower pace. This biphasic behavior has been also reported for other natural materials, such as wild sugar cane ( Saccharum spontaneous ) [ 26 ] and pine sawdust [ 27 ]. Accordingly, the degradation of submerged organic materials seems to start with a leaching phase, which is followed by a hydrolysis phase characterized by the breakdown of the released macromolecules into simpler compounds.…”

“…During leaching tests, submerged plant material releases soluble compounds due to the breakdown of the vacuoles of plant cells by the physical action of water [ 26 ]. The analysis of both the elemental composition and the FT-IR spectra of the lyophilized 50-day leachates provided information about the compounds solubilized preferentially from the solid matrix.…”

Enhanced Biological Nitrate Removal from Groundwater in Humid Tropical Regions Using Corn Cob-Based Permeable Reactive Barriers: A Case Study from Panama

“…This test was performed in triplicate using 500 mL glass bottles previously sterilized. Each reactor contained 4.04 ± 0.05 g of corn cob, which was disinfected using ultraviolet light (365 nm) to prevent microbial interference or crosscontamination [19]. To each reactor, 400 mL of sterilized distilled water was added [22].…”

“…The reactors were agitated on a magnetic stirrer at 300 rpm at room temperature for 14 and 12 days, respectively. To maintain anoxic conditions, the reactors were purged with nitrogen gas for 3 to 5 min [19]. Additionally, 3 mg/L of dipotassium phosphate buffer (K 2 HPO 4 ) was added to keep the pH between 6 and 7.5.…”

“…Such an abundance of waste presents an opportunity to use this resource for environmental remediation. Therefore, this study aimed to explore the potential of corn cobs for removing nitrate from contaminated groundwater Among the agricultural residues previously studied in the literature for their potential in nitrate removal are wheat straw [16], mulch [17], luffa [18], canal straw [19], and corn cob [20]. For instance, Xu et al [21] research demonstrated that corn cobs could remove over 90% of nitrate from wastewater, showcasing their potential as an economical and effective carbon source for denitrification.…”