Temperature effects on nitrogen removal and NO emissions in anammox reactors.

Mainstream anammox faces challenges in adapting to non-optimal temperatures and managing greenhouse gas emissions. This study investigates nitrogen removal and NO emissions in attached-growth anammox reactors subjected to rapid temperature shifts (15 - 55 °C). Temperature reductions to 15 - 25 °C had minimal impact on the anammox bacterial populations, with nitrogen removal rates of 0.

Effects of hydrothermal treatment on the reduction of antibiotic-resistant Escherichia coli and antibiotic resistance genes and the fertilizer potential of liquid product from cattle manure.

In this study, the reduction in the abundance of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) and the fertilizer potential of liquid products from hydrothermally treated cattle manure were investigated. Hydrothermal treatment (HTT) was conducted under different reaction temperatures (125, 150, 175 and 200 °C) and retention times (60, 90 and 120 min). The total organic carbon (TOC) and total nitrogen (TN) of the liquid product increased with increasing reaction temperature.

Comparison on removal performance of virus, antibiotic-resistant bacteria, cell-associated and cell-free antibiotic resistance genes, and indicator chemicals by ozone in the filtrated secondary effluent of a sewage treatment plant.

Due to the widespread appearance of viruses, antibiotic-resistant bacteria (ARBs), and antibiotic resistance genes (ARGs) in the aquatic environment, more powerful oxidation processes such as ozonation are needed to enhance the efficiency of their inactivation and removal during wastewater treatment. However, information is lacking on the elimination rates of viruses, ARBs, cell-associated ARGs (ca-ARGs), and cell-free ARGs (cf-ARGs) during ozonation. This study examined the kinetics and dose-dependent inactivation of a virus (MS2 coliphage) and an ARB (Ampicillin-resistant [Amp] E.

Evaluation of nitrous oxide emission during ammonia retention from simulated industrial wastewater by microaerobic activated sludge process.

Considering the reciprocating processes of nitrogen gas (N) fixation to ammonia (NH-N) and NH-N removal to N through nitrification and denitrification during wastewater treatment, a microaerobic activated sludge process (MAS) is proposed in this study as a pretreatment to retain NH-N from high-strength nitrogenous wastewater for further NH-N recovery through membrane technology, that is, inhibit nitrification, with sufficient removal of total organic carbon (TOC). With DO and pH control, the 3-reactor bench-scale MAS systems successfully realized an NH-N retention rate of over 80 %, with TOC removal rates of over 90 %. In addition, the emissions of carbon dioxide (CO) and nitrous oxide (NO) during MAS were evaluated.

Prediction of calcium phosphate generation and behaviors of metals during phosphorus recovery using a modified thermodynamic model.

In this study, behaviors of metals and their effects on phosphorus recovery by calcium phosphate were investigated by the laboratory and pilot experiments as well as by the modified thermodynamic model. Batch experimental results indicated that the efficiency of phosphorus recovery decreased with the increase in metal content and more than 80% phosphorus can be recovered with a Ca/P molar ratio of 3.0 and a pH of 9.

Development of two microbial source tracking markers for detection of wastewater-associated Escherichia coli isolates.

Escherichia coli has been used as an indicator of fecal pollution in environmental waters. However, its presence in environmental waters does not provide information on the source of water pollution. Identifying the source of water pollution is paramount to be able to effectively reduce contamination.

Comparative anaerobic digestion of sewage sludge at different temperatures with and without heat pre-treatment.

Anaerobic digestion of sewage sludge is generally conducted under mesophilic (around 35 °C) or thermophilic (around 55 °C) conditions, whereas it is conducted at lower temperatures in some wastewater treatment plants without heating. In this study, we compared the anaerobic digestion of sewage sludge at 15, 25, 30, 35, 45, and 55 °C following hyperthermophilic pre-treatment at 80 °C for 24 h. Laboratory-scale reactors were operated continuously for more than 1000 days, and batch experiments were performed to evaluate the reaction kinetics.

Anammox reactor exposure to thiocyanate: Long-term performance and microbial community dynamics.

Anaerobic ammonium oxidation (anammox) is an autotrophic denitrification process that has broad application potential for treating coking wastewaters. The present study estimated the effects of thiocyanate (SCN), a common pollutant in coking wastewaters, on anammox processes and microbial communities in anammox reactors for over two years of continuous exposure. The addition of SCN (from 50 to 200 mg L) showed negative effects on the denitrification performance of the anammox reactors.

Utilization of high solid waste activated sludge from small facilities by anaerobic digestion and application as fertilizer.

Anaerobic co-digestion of sewage sludge with organic wastes has recently gained attention in small facilities. For small facilities, high solids sludge is suitable for transportation to a centralized co-digester, and direct utilization of the digested sludge as liquid fertilizer is recommended. Effects of high solid and hyperthermophilic pretreatment (80 °C, 24 hr) on anaerobic digestion at low temperatures and utilization as fertilizer are investigated by anaerobic/aerobic digestion and paddy soil incubation experiments.

Spatial and daily variations of nitrous oxide emissions from biological reactors in a full-scale activated sludge anoxic/oxic process.

Nitrous oxide (NO) is an important greenhouse gas that can be emitted from wastewater treatment plants (WWTPs). Such emissions are reportedly process specific and related to operational parameters. This study was conducted to clarify spatial and daily variations of NO in a full-scale activated sludge anoxic/oxic process that consisted of an anoxic tank and three oxic tanks (oxic-1, oxic-2 and oxic-3), all of which except the final sedimentation tank were fully covered.

Enhanced generation of perfluoroalkyl carboxylic acids (PFCAs) from fluorotelomer alcohols (FTOHs) via ammonia-oxidation process.

With the phase-out of persistent, bioaccumalative, and toxic perfluoroalkyl carboxylic acids (PFCAs), it is needed to explore the potential release of PFCAs from precursors being emitted into the environment. Biotransformation of fluorotelomer alcohols (FTOHs) via biological processes in wastewater treatment plants (WWTPs) leads to discharge of PFCAs into receiving waters. However, the commonly existed microbial activity that can impact on FTOHs biodegradation in WWTPs remains unclear.

Effects of microbial activity on perfluorinated carboxylic acids (PFCAs) generation during aerobic biotransformation of fluorotelomer alcohols in activated sludge.

Biotransformation of fluorotelomer alcohols (FTOHs) in wastewater treatment plants (WWTPs) can release toxic intermediates and perfluorinated carboxylic acids (PFCAs) to the aqueous environment. However, little information is known about the role of relevant microbial activity (i.e.

Effect of alkaline microwaving pretreatment on anaerobic digestion and biogas production of swine manure.

Microwave assisted with alkaline (MW-A) condition was applied in the pretreatment of swine manure, and the effect of the pretreatment on anaerobic treatment and biogas production was evaluated in this study. The two main microwaving (MW) parameters, microwaving power and reaction time, were optimized for the pretreatment. Response surface methodology (RSM) was used to investigate the effect of alkaline microwaving process for manure pretreatment at various values of pH and energy input.

Nitrogen behavior during sludge ozonation: a long-term observation by pilot experiments.

Sludge ozonation is a promising technology for dealing with the increasing challenge of excess sludge treatment and disposal. However, nitrogen behavior during sludge ozonation and subsequent biological removal remains unclear. To clarify the feasibility and stability of oxidizing organic nitrogen (released during sludge ozonation) in the bioreactor (but not during ozonation), and the best operational conditions for sludge ozonation, nitrogen behavior was investigated by a long-term observation.

Changes of microbial substrate metabolic patterns through a wastewater reuse process, including WWTP and SAT concerning depth.

In this study, changes of microbial substrate metabolic patterns by BIOLOG assay were discussed through a sequential wastewater reuse process, which includes activated sludge and treated effluent in wastewater treatment plant and soil aquifer treatment (SAT), especially focussing on the surface sand layer in conjunction with the vadose zone, concerning sand depth. A SAT pilot-scale reactor, in which the height of packed sand was 237 cm (vadose zone: 17 cm and saturated zone 220 cm), was operated and fed continuously by discharged anaerobic-anoxic-oxic (A2O) treated water. Continuous water quality measurements over a period of 10 months indicated that the treatment performance of the reactor, such as 83.

Behavior of inorganic elements during sludge ozonation and their effects on sludge solubilization.

The behavior of inorganic elements (including phosphorus, nitrogen, and metals) during sludge ozonation was investigated using batch tests and the effects of metals on sludge solubilization were elucidated. A decrease of ∼ 50% in the ratio of sludge solubilization was found to relate to a high iron content 80-120 mgFe/gSS than that of 4.7-7.

Applicability of Corbicula as a bioindicator for monitoring organochlorine pesticides in fresh and brackish waters.

The applicability of Corbicula as a bioindicator for monitoring organochlorine pesticides (OCPs) in fresh and brackish waters is presented here. Differences in isomer compositions and OCP bioaccumulation levels were analyzed in western Japan and the Pearl River Delta (PRD) in China. Isomer compositions of DDTs, chlordanes, and HCHs were significantly different between the two areas because of their different historical uses and property of the chemicals.

Investigation of 1,4-dioxane originating from incineration residues produced by incineration of municipal solid waste.

As a groundwater contaminant, 1,4-dioxane is of considerable concern because of its toxicity, refractory nature to degradation, and rapid migration within an aquifer. Although landfill leachate has been reported to contain significant levels of 1,4-dioxane, the origin of 1,4-dioxane in leachate has not been clarified until now. In this study, the origins of 1,4-dioxane in landfill leachate were investigated at 38 landfill sites and three incineration plants in Japan.

Occurrence of tributyltin (TBT)-resistant bacteria is not related to TBT pollution in Mekong River and coastal sediment: with a hypothesis of selective pressure from suspended solid.

Tributyltin (TBT) is organotin compound that is toxic to aquatic life ranging from bacteria to mammals. This study examined the concentration of TBT in sediment from and near the Mekong River and the distribution of TBT-resistant bacteria. TBT concentrations ranged from <2.

Determination of sex hormones and nonylphenol ethoxylates in the aqueous matrixes of two pilot-scale municipal wastewater treatment plants.

Two analytical methods were developed and refined for the detection and quantitation of two groups of endocrine-disrupting chemicals (EDCs) in the liquid matrixes of two pilot-scale municipal wastewater treatment plants. The targeted compounds are seven sex hormones (estradiol, ethinylestradiol, estrone, estriol, testosterone, progesterone, and androstenedione), a group of nonionic surfactants (nonylphenol polyethoxylates), and their biodegradation byproducts nonylphenol and nonylphenol ethoxylates with one, two, and three ethoxylates. Solid phase extraction using C-18 for steroids and graphitized carbon black for the surfactants were used for extraction.

A simple biofilm model of bacterial competition for attached surface.

A simple biofilm model of competition in bacterial growth for an attached surface is developed. Competition for the attached surface is expressed with the crowded and detachment effects. The developed model is verified by comparing simulated results with data obtained in the experiments of batch culture of nitrifier and continuous treatment of actual sewage with biofilm reactor.