Drinking water decontamination by biological denitrification using fresh bamboo as inoculum source

Abstract

Groundwater contamination is becoming a serious problem in many Brazilian regions. European countries started to deal with this issue in the 1980s, mainly caused by the extensive usage of nitrogenous fertilizers and the absence of domestic wastewater treatment. Due to its high solubility, nitrate readily passes through the soil and reaches the aquifer. Thereafter, this ion moves, following groundwater flow, and can be found several kilometers from the area where the pollution occurred. Concern about nitrate contamination is due to the link found between this contaminant and various human health diseases, such as methemoglobin and cancer. Studies carried out in France enabled the design and implementation of several biological denitrification plants throughout the country, in order to remove nitrate from its contaminated groundwater. Heterotrophic denitrification facilities shown to be adequate to treat high water flows with satisfactory nitrate removal efficiency, especially when static media supports are employed. The objective of this research was to evaluate the existence of denitrifying microorganisms in bamboo (Bambusa tuldóides) and verify the feasibility of their use to inoculate a pilot-scale fixed-bed bioreactor. The support material selected to fill the bioreactor bed was commercial polypropylene Pall rings, since such support has a high porosity associated with a wide superficial area. The bioreactor was able to produce and retain a large amount of cells. Using ethanol as carbon source, nitrate (N-NO3(-)) removal efficiency of the bioreactor stood around 80 % for a maximum nitrogen loading rate of approximately 6.5 mg N-NO3 (-) L(-1) h(-1).

Valorization of Agro-Industrial By-products: Use of Rice Husk as a Source of Microorganisms to Denitrification of Water

“…At 40 °C and 50 °C and using MOSO, denitrification processes were less efficient than at 25 °C and 30 °C. These data corroborate with most of the reported studies that indicate an ideal denitrification temperature between 20 °C and 30 °C (Figure 2A) (Bucco et al, 2014;Liu et al, 2012).…”

Optimization of the electrochemical reduction process and ORP effects in nitrate removal

“…So far, various methods have been designed and implemented to remove nitrate from the water. Some biological processes (nitrification-denitrification) (Bucco et al, 2014;Cao et al, 2014;Yazdanbakhsh et al, 2008), physical and chemical methods such as ion exchange (Alikhani & Moghbeli, 2014;Meng et al, 2014), reverse osmosis (Ersever et al, 2014), and electrodialysis (Bernardes et al, 2016) are significant ones. In the last decades, electrochemical technology for water and wastewater treatment has attracted considerable attention (Gao et al, 2021;Wang et al, 2020;Yao et al, 2021).…”

Poly(butylene succinate)/bamboo powder blends as solid-phase carbon source and biofilm carrier for denitrifying biofilters treating wastewater from recirculating aquaculture system

“…Blending BDPs with a cheap organic material such as bamboo powder or starch was proven to be a promising way to lower their cost while maintaining their good bioavailability for nitrate wastewater treatment 24 . Bamboo, as a clean and cheap material with great tensile and impact strength, has alone been demonstrated to be an acceptable carbon source for nitrate removal in groundwater treatment 25 . Furthermore, PCL/BP blends and PBS, PCL, PLA and PHBV blended with starch have all been proven to be environment-friendly biopolymer blends with relatively low cost 24 , 26 , 27 .…”