Ammonium oxidation from concentrated synthetic wastewater and landfill leachate using partial nitritation in sequencing batch reactor.

Partial nitritation (PN) is a novel treatment for nitrogen removal using aerobic ammonium oxidation with reduced oxygen requirements compared to conventional nitrification. This study evaluated the performance of the PN process and the factors influencing nitrogen removal from landfill leachate. During the reactivation of biomass, the results showed 70% ammonium removal, but only 20% total nitrogen removal.

Factors associated with elevated levels of antibiotic resistance genes in sewer sediments and wastewater.

The sewer environment is a potential hotspot for the proliferation of antibiotic resistance genes (ARGs) and other hazardous microbial agents. Understanding the potential for ARG proliferation and retardation and/or accumulation in sewer sediments is of interest for protecting the health of sewage workers and the broader community in the event of sewer overflows as well as for interpreting sewage epidemiology data. To better understand this understudied environment for antibiotic resistance, a field survey was conducted to identify the factors that may control ARGs in sewer sediments and sewage.

Metabolically Active Prokaryotes and Actively Transcribed Antibiotic Resistance Genes in Sewer Systems: Implications for Public Health and Microbially Induced Corrosion.

Sewer systems are reservoirs of pathogens and bacteria carrying antibiotic resistance genes (ARGs). However, most recent high-throughput studies rely on DNA-based techniques that cannot provide information on the physiological state of the cells nor expression of ARGs. In this study, wastewater and sewer sediment samples were collected from combined and separate sanitary sewer systems.

Sewer biofilm microbiome and antibiotic resistance genes as function of pipe material, source of microbes, and disinfection: field and laboratory studies.

Wastewater systems are recognized pathways for the spread of antibiotic resistant bacteria, but relatively little is known about the microbial ecology of the sewer environment. Sewer biofilm colonization by antibiotic resistance gene (ARG) carrying bacteria may impact interpretations of sewage epidemiology data, water quality during sewer overflows, and hazard to utility workers. The objectives of this research were to evaluate the (1) microbiome of real and simulated sewer biofilms and their potential to accumulate ARGs and (2) susceptibility of simulated sewer biofilms to bleach disinfection.

Viability-based quantification of antibiotic resistance genes and human fecal markers in wastewater effluent and receiving waters.

Antibiotic resistance is a public health issue with links to environmental sources of antibiotic resistance genes (ARGs). ARGs from nonviable sources may pose a hazard given the potential for transformation whereas ARGs in viable sources may proliferate during host growth or conjugation. In this study, ARGs in the effluent from three municipal wastewater treatment plants (WWTPs) and the receiving surface waters were investigated using a viability-based qPCR technique (vPCR) with propidium monoazide (PMA).

Peracetic acid disinfection kinetics for combined sewer overflows: indicator organisms, antibiotic resistance genes, and microbial community.

Combined sewer overflows (CSOs) degrade water quality and end-of-pipe treatment is one potential solution for retrofitting this outdated infrastructure. The goal of this research was to evaluate peracetic acid (PAA) as a disinfectant for CSOs using viability based molecular methods for antibiotic resistance genes (ARGs), indicator organism marker gene BacHum, and 16S rRNA genes. Simulated CSO effluent was prepared using 23-40% wastewater, representing the higher end of the range of wastewater concentrations reported in CSO effluent.

Partitioning of Antibiotic Resistance Genes and Fecal Indicators Varies Intra and Inter-Storm during Combined Sewer Overflows.

Combined sewer overflows (CSOs) degrade water quality through the release of microbial contaminants in CSO effluent. Improved understanding of the partitioning of microbial contaminants onto settleable particles can provide insight into their fate in end-of-pipe treatment systems or following release during CSO events. Sampling was performed across the hydrograph for three storm events as well as during baseflow and wet weather in three surface waters impacted by CSO.

Shifts in microbial community structure and function in surface waters impacted by unconventional oil and gas wastewater revealed by metagenomics.

Unconventional oil and gas (UOG) production produces large quantities of wastewater with complex geochemistry and largely uncharacterized impacts on surface waters. In this study, we assessed shifts in microbial community structure and function in sediments and waters upstream and downstream from a UOG wastewater disposal facility. To do this, quantitative PCR for 16S rRNA and antibiotic resistance genes along with metagenomic sequencing were performed.

In situ bioremediation of perchlorate in vadose zone soil using gaseous electron donors: microcosm treatability study.

A series of microcosm experiments were performed to determine the effectiveness of various gaseous electron donors (including hydrogen, 1-hexene, ethyl acetate, and liquefied petroleum gas [LPG]) for supporting biological perchlorate reduction under different electron donor concentrations and soil moistures. Under high soil moisture (16% w/w) conditions, complete or partial perchlorate degradation was achieved with all of the tested electron donors, except for ethyl acetate. Hydrogen was the most promising of the tested electron donors, achieving complete perchlorate degradation with first-order rate constants ranging from 0.