Alongside offering customizable solutions, Delco Water also prides itself on it’s strong Research and Development front. Constantly seeking out the most efficient methods of water treatment technologies, Delco’s Research and Development team specializes in the evaluation of new technology ideas and processes by screening them for their potential to add improvements to current systems. Their highly advanced hands-on skills and attention to design, verification, testing, and development of methodologies and processes result in cost reduction in commercial projects and process development for water and wastewater system treatment.

Their expertise has led them to find groundbreaking new methods for variety of water treatment technologies, such as Biological Filtration, Acid Mine Drainage Treatment, Activated Carbon, Reverse Osmosis, Nanofiltration, MBR, De-Oiling, Sludge Digestion, Electron-Beam, and Ozonation. Our Research and Development team often attends conferences throughout North America to educate others on specific subjects and findings.


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Biofiltration Field Study for Cold Fe(II)- and Mn(II)-Rich Groundwater: Accelerated Mn(II) Removal Kinetics and Cold-Adapted Mn(II)-Oxidizing Microbial Populations


Removal of Mn(II) from Fe(II)- and  Mn(II)-rich groundwater in cold regions is challenging, due  to slow Mn(II) removal kinetics below 15 C. This study demonstrated onset, acclimation, and acceleration of Mn(II) removal in a two-stage pilot-scale biofilter (Fe and Mn filters) at varying low on-site temperatures (8–14.8 C). Mn(II) removal commenced at 8 C in the Mn filter after Fe(II) removal. A shift in redox-pH conditions favored biological Mn(II) removal and Mn(II)-oxidizing bacteria increased. The Mn filter reached steady-state functioning after 97 days, exhibiting high removal efficiencies (97 ± 0.9%). Yet, first-order rate constants (k) for Mn(II) removal were low (10   6–10  5 min 1;t1/2 ¼ ∼40 d). After consecutive backwashes and filter inoculation with backwashed sludge, k remarkably accelerated to 0.21 min 1 (t1/2 ¼ 3.31 min at 11 ± 0.6 C). The cold-adapted microbial consortium (51 genera), including Pseudomonas, Leptothrix, Flavobacterium, and Zoogloea, cultured from the field-aged biofilter rapidly produced biogenic Mn oxides at 8 C, confirmed by electron paramagnetic resonance spectroscopy. Birnessite and pyrolusite detected by synchrotron-based powder X-ray diffraction, and a repetitive birnessite-like surface morphology on ripened filter materials, reflected autocatalytic oxidation. Shifting in k indicated the vertical progress of biofilter ripening, which was not limited by low temperature.

Microbial Communities and Biogenic Mn-Oxides in an On-Site Biofiltration System for Cold Fe-(II)- and Mn(II)-Rich Groundwater Treatment

This study investigated relationships betweenmicrobial communities, groundwater chemistry, and geochemical and mineralogical characteristics in field-aged biofilter media from a two-stage, pilot-scale, flow-through biofiltration unit designed to remove Fe(II) and Mn(II) from cold groundwater (8 to 15 °C). High-throughput 16S rRNA gene amplicon sequencing of influent groundwater and biofilter samples (solids, effluents, and backwash water) revealed significant differences in the groundwater, Fe filter, and Mn filter communities. These community differences reflect conditions in each filter that select for populations that biologically oxidize Fe(II) and Mn(II) in the two filters, respectively. Genera identified in both filters included relatives of known Fe(II)-oxidizing bacteria (FeOB), Mn(II)-oxidizing bacteria (MnOB), and ammonia-oxidizing bacteria (AOB). Relatives of AOB and nitrite-oxidizing bacteria were abundant in sequencing reads from both filters. Relatives of FeOB in class Betaproteobacteria dominated the Fe filter. Taxa related to Mn-oxidizing organisms were minor members of the Mn-filter communities; intriguingly, while Alphaproteobacteria dominated (40 ± 10% of sequencing reads) the Mn filter community, these Alphaproteobacteria did not classify as known MnOB. Isolates from Fe and Mn filter backwash enrichment studies provide insight on the identity of MnOB in this system. Novel putative MnOB isolates included Azospirillum sp. CDMB, Solimonas soli CDMK, and Paenibacillus sp. CDME. The isolate Hydrogenophaga strain CDMN can oxidize Mn(II) at 8 °C; this known FeOB is likely capable of Mn(II) oxidation in this system. Synchrotron-based X-ray near-edge spectroscopy (XANES) coupled with electron paramagnetic resonance (EPR) revealed the dominant Mn-oxide that formed was biogenic birnessite. Co-existence of amorphous and crystallizedMn-oxide surfacemorphologies on the Mn-filtermedia suggest occurrence of both biological and autocatalytic Mn(II) oxidation in the biofilter. This study provides evidence that biofiltration is a viable approach to remove iron, manganese, and ammonia in cold groundwater systems, and that mineralogical and microbiological approaches can be used to monitor biofiltration system efficacy and function.