A poly-ε-caprolactone based biofilm carrier for nitrate removal from water

Abstract

Nitrate removal from water has been accomplished by heterotrophic biofilms using organic carbon as a source of reducing power. To overcome the natural limitation in organic carbon in water, a poly-e-caprolactone based biofilm carrier that serves simultaneously as a biofilm carrier and as a source of organic carbon was developed and tested in the present work. The feasibility of the new biofilm carrier for nitrate removal from water was evaluated in a packed bed reactor. The combination of size and structure provided a carrier element having high surface area and void volume, 1,170 m 2 /m 3 and 67 %, respectively. A maximum denitrification rate of 4.4 mg N-NO 3 -/(L.h) (9.2 mg N-NO 3 -/(m 2 .h)) was achieved in the packed bed reactor at 20°C and pH 7.0. Main advantages of the biofilm carrier developed in the present work are its mechanical stability in water even after biofilm formation and controlled release of organic carbon by enzymatic reactions. The proposed biotechnology to remove nitrate from groundwater is robust and easy to operate.

Optimization of nitrate removal from wastewater with a low C/N ratio using solid-phase denitrification

“…Biodegradable polymers (BDPs), which act as both an energy source and biofilm carrier, have sparked great interest in the scientific community Wu et al 2013a, b;Shen and Wang 2011;Rodrigues et al 2014;Walters et al 2009). In contrast to conventional treatment units, denitrification with biodegradable polymers facilitates operation.…”

Comparison of Clay Ceramsite and Biodegradable Polymers as Carriers in Pack-bed Biofilm Reactor for Nitrate Removal

“…Previous studies mainly focused on materials selection [14,15] and the determination of specific nitrogen removal efficiencies of different BDPs [8,12,16]. However, comprehensive solid-phase denitrification processes are lacking and the results vary with the type [7,17,18,19,20], structure [21,22] and molecular weight [23] of BDPs. Rodrigues et al [22] found that the same type of BDPs showed different performance on volumetric nitrate removal rate when comparing with the previous literature [5,24] since the BDPs employed in the different works have different physical-chemical properties.…”

“…However, comprehensive solid-phase denitrification processes are lacking and the results vary with the type [7,17,18,19,20], structure [21,22] and molecular weight [23] of BDPs. Rodrigues et al [22] found that the same type of BDPs showed different performance on volumetric nitrate removal rate when comparing with the previous literature [5,24] since the BDPs employed in the different works have different physical-chemical properties. Thus, a direct results comparison between solid-phase denitrification and conventional denitrification processes for the different denitrification performances between the two processes during the start-up period and under adverse running conditions (i.e., low carbon to nitrogen (C/N) ratio, short hydraulic retention time (HRT) and continuous shock nitrate loadings) is essential.…”

Effects of Temperature on the Characteristics of Nitrogen Removal and Microbial Community in Post Solid-Phase Denitrification Biofilter Process

“…In addition, the organic carbon released from PCL could also eliminate the dissolved oxygen in the influent to maintain the anoxic environment. Previous studies have also shown that the solid carbon source has a high mechanical strength and a very long service life (mass loss of 0.03% per day), so that a long-term stable denitrification performance can be maintained in SPDB [13]. In previous research, using various biodegradable polymers (e.g., PHB, PCL, PLA and polymer blends) as both a carbon source and biofilm support for treating nitrate contaminated water in a single reactor (e.g., packed-bed and moving bed biofilm reactor, constructed wetland, etc.)…”