Novel fluidized-bed biofilm reactor for concomitant removal of microcystin-LR and organics

Abstract

Fluidized bed biofilm reactor (FBBR) was evaluated for the removal of microcystin-LR (MC-LR) from drinking water-sludge (0.3 % w/v). Biofilm formed inside the solid media carriers (biocarriers) were studied for the MC-LR degradation in FBBRs via known MC-LR degraders: Arthrobacter ramosus (reactor A: RA) and Bacillus sp. (reactor B: RB), along with the heterogeneous bacterial community (HBC) present in the sedimentation-unit sludge as a background matrix. Their ability to form biofilm inside the immobilized biocarriers was periodically quantified for over 300 days to determine the duration of mature biofilm growth, sloughing event and then re-maturation. The bioreactor performance was mainly evaluated in 2 terms of MC-LR, nitrate, nitrite, ammonia removal, and soluble-chemical oxygen demand (s-COD) removal. Biological degradation of MC-LR showed significant role over the physical adsorption, as the removal efficiency increased by around 30 % and 26 % for RA and RB respectively, as compared to the control bioreactor RD (without any bacterial cells) and an increase by over 15 % and 11 % when compared to reactor RC (contained only HBC). Mass spectra analysis for RA, RB, and RC strengthen the possibility of a toxic-free degradation mechanism. Overall, RA showed the best MC-LR removal efficiency of around 93.7 %, which comprised no MC-LR in the supernatant phase and around 3 µg/L in the sludge-mixture phase. Toxicity assessment of biodegraded sample (using bioindicator) further revealed the toxic-free nature by RA with more than 80 % removal for ammonia, nitrate, and nitrite. Scale-up of laboratory scale FBBR (2 L) is also proposed to handle 200 m 3 of feed water per day based on a similar volumetric mass transfer coefficient (kLa) to study the feasible process economics.

Co-culturing of native bacteria from drinking water treatment plant with known degraders to accelerate microcystin-LR removal using biofilter

“…S10). These seven major by-products were similar to the degraded by-products as reported in our previous research work, where MC-LR removal was studied using moving bed biofilm reactors (MBBR) [41]. It may be because same MC-LR-degraders were bioaugmented individually in separate MBBR reactor for the development of the biofilm over the K1 Kaldness adsorbents.…”

Biological fixed‐film systems

“…In addition, the highest percentage (87%) of hydrogen gas was confirmed at a hydraulic retention time of 12 hr. Kumar et al (2019) studied the removal of microcystin-LR (MC-LR) and organics in a novel fluidized-bed biofilm reactor (FBBR). Two reactors (RA: Arthrobacter ramosus reactor and RB: Bacillus sp.…”

“…Kumar et al (2019) studied the removal of microcystin‐LR (MC‐LR) and organics in a novel fluidized‐bed biofilm reactor (FBBR). Two reactors (RA: Arthrobacter ramosus reactor and RB: Bacillus sp.…”

The Effect of a Combined Hydrogen Peroxide-MlrA Treatment on the Phytoplankton Community and Microcystin Concentrations in a Mesocosm Experiment in Lake Ludoš

“…Such an arrangement not only suppresses the growth of cyanobacteria or induces their death, but also enables a simultaneous, fast degradation of the MC released from the cells disrupted by the algicide. Recently, some new methods of biological MC degradation have been presented [14][15][16], however these proposals only offer ex situ treatment of contaminated water in bioreactors designed for MC removal from filtered water. Another approach is in situ bioremediation, which requires the production of an enzyme that is capable of MC degradation by well-established heterologous systems and the release of the enzyme into the environment.…”