Performance of sanitary sewer collection system odour control devices operating in diverse conditions

Controlling odours from sanitary sewer systems is challenging as a result of the expansive nature of these systems. Addition of oxidizing chemicals is often practiced as a mitigation strategy. One alternative is to remove odorous compounds in the gases vented from manholes using adsorptive media. In this study, odour control devices located at manholes were observed to determine the ability of these systems to reduce hydrogen sulphide from vented gases. The odour control devices incorporated pressure regulation to control gas flow out of manhole covers and adsorptive media to remove hydrogen sulphide in the vented gases prior to release. Pressure regulation was accomplished using a variable volume bladder and two pressure relief valves that permitted gas flow when pressures exceeded 1.3 to 2.5 cm water column. The reduction in gas flow vented from manholes was intended to extend the service life of the adsorptive media, as compared with odour control devices that do not incorporate pressure modulation. Devices were deployed at four locations and three adsorptive media were tested. Although measured collection system hydrogen sulphide concentrations varied from zero to over 1,000 ppm, the removal rates observed using odour control devices were typically above 90%. The lower removal rates observed at one of the sites (50.5 ± 36.1%) appeared related to high gas flow rates being emitted at this location. Activated carbon was used in most of the tests, although use of iron media resulted in the highest removal observed: 97.8 ± 3.6%. The expected service life of the adsorptive media contained within the odour control devices is a function of site-specific hydrogen sulphide concentrations and gas flow rates. The units used in this study were in service for more than 8 to 12 months prior to requiring media replacement

Treatment of oil-water emulsion from the machinery industry by Fenton’s reagent

An oil–water emulsion from the machinery industry was treated using Fenton\u27s reagent. The objective was to reduce the high chemical oxygen demand (COD) of this waste stream so that it would meet the COD effluent limit of Chinese Standard JS-7740-95. The optimal [H2O2]/[Fe2+] ratio for COD removal was 3. An orthogonal experimental design was developed based on the optimal [H2O2]/[Fe2+] ratio to evaluate the significance of four parameters relevant to the treatment process, namely, H2O2 dosage, initial pH, oxidation time and coagulation pH. The influence of the four parameters on COD removal efficiency decreased as follows: H2O2 dosage \u3e oxidation time \u3e coagulation pH \u3e initial pH. The COD removal efficiency was further investigated based on the most important single-factor parameter, which was H2O2 dosage, as discovered in the orthogonal test. A well-fitted empirical correlation was obtained from the single-factor analysis and up to 98% COD removal was attained using 50 mM H2O2. Using the doses and conditions identified in this study, the treated oil–water emulsion can be discharged according to Chinese Standard JS-7740-95

V1647 Ori (IRAS 05436-0007) in Outburst: the First Three Months

We report on photometric (BVRIJHK) and low dispersion spectroscopic observations of V1647 Ori, the star that drives McNeil's Nebula, between 10 February and 7 May 2004. The star is photometrically variable atop a general decline in brightness of about 0.3-0.4 magnitudes during these 87 days. The spectra are featureless, aside from H-alpha and the Ca II infrared triplet in emission, and a Na I D absorption feature. The Ca II triplet line ratios are typical of young stellar objects. The H-alpha equivalent width may be modulated on a period of about 60 days. The post-outburst extinction appears to be less than 7 mag. The data are suggestive of an FU Orionis-like event, but further monitoring will be needed to definitively characterize the outburst.Comment: Accepted for publication in the Astronomical Journa

Use of the WARMF Model to Identify Sources of Oxygen Impairment and Potential Management Strategies for the San Joaquin River Watershed

Eutrophication of the San Joaquin River (SJR) has resulted in low dissolved oxygen (DO) conditions, which has led to a regulatory response and development of total maximum daily load (TMDL) allocations. Due to the dynamic nature of processes governing oxygen depletion in the SJR, a model was needed to help stakeholders understand the fate and transport of nutrients and oxygendemanding substances that cause the low DO conditions. Here, the Watershed Analysis Risk Management Framework (WARMF) model was used to simulate nutrient removal and control strategies, accounting for the secondary effects of growth and transformation between sources and discharge. Using the management alternatives in the WARMF Consensus Module, simulations were run to test the global removal of nutrient inputs on downstream phytoplankton growth, a major contributor of oxygen demand in the SJR. In the simulations, removal of ammonia had the greatest impact on downstream phytoplankton, causing a 32% reduction, while removal of phosphate and nitrate caused reductions of 25% and 13%, respectively. When ammonia and nitrate were both removed, phytoplankton reduction was 62%. These model results suggest that nitrogen control programs would be more effective than phosphorus programs. Using the Data Module in WARMF, input files were modified to determine the impacts of individual tributaries and agricultural drainages. In each simulation, the contributing loads for individual inputs were removed while maintaining flow. According to the model output, the largest impact on phytoplankton occurred with the removal of mass loads from Salt Slough (32% less than baseline). The effect of removing the mass loads from Mud Slough had a slightly lower impact (26% less than baseline). The WARMF model proved useful for exploration of planning and management alternatives, providing an expert decision-making tool that is available to stakeholders

Use of a onedimensional link-node model to develop total maximum daily load strategies for the San Joaquin River Estuary

A one-dimensional link-node model was used to simulate water quality conditions in the tidallyinfluenced, deep water ship channel (DWSC) of the San Joaquin River located in Central California. The DWSC has been plagued with low dissolved oxygen (DO) conditions for decades and is currently a focus of restoration efforts. The model was calibrated using a six-year flow and water quality data set. Model simulations were run by removing the mass loads of each of the following major sources of oxygen depletion to determine the effects: elimination of the deepened ship channel (i.e., restore to its preexisting depth), elimination of import of oxygen-demanding substances (ODS) from the San Joaquin River watershed, elimination of import of ODS from the urban tributaries, and elimination of discharge of ODS from the City of Stockton regional wastewater control facility. The model results suggest that elimination of the deepened ship channel resulted in the best projected improvement relative to the modelled baseline with a predicted 55% improvement, while reducing ODS from the watershed would likely cause a 44% improvement. These results demonstrate that there are multiple contributing factors causing low DO in the DWSC and that removal or elimination of any single variable will not result in a complete resolution of low DO events

Temperature and injection water source influence microbial community structure in four Alaskan North Slope hydrocarbon reservoirs

A fundamental knowledge of microbial community structure in petroleum reservoirs can improve predictive modeling of these environments. We used hydrocarbon profiles, stable isotopes, and high-density DNA microarray analysis to characterize microbial communities in produced water from four Alaskan North Slope hydrocarbon reservoirs. Produced fluids from Schrader Bluff (24–27°C), Kuparuk (47–70°C), Sag River (80°C), and Ivishak (80–83°C) reservoirs were collected, with paired soured/non-soured wells sampled from Kuparuk and Ivishak. Chemical and stable isotope data suggested Schrader Bluff had substantial biogenic methane, whereas methane was mostly thermogenic in deeper reservoirs. Acetoclastic methanogens (Methanosaeta) were most prominent in Schrader Bluff samples, and the combined δD and δ13C values of methane also indicated acetoclastic methanogenesis could be a primary route for biogenic methane. Conversely, hydrogenotrophic methanogens (e.g., Methanobacteriaceae) and sulfide-producing Archaeoglobus and Thermococcus were more prominent in Kuparuk samples. Sulfide-producing microbes were detected in all reservoirs, uncoupled from souring status (e.g., the non-soured Kuparuk samples had higher relative abundances of many sulfate-reducers compared to the soured sample, suggesting sulfate-reducers may be living fermentatively/syntrophically when sulfate is limited). Sulfate abundance via long-term seawater injection resulted in greater relative abundances of Desulfonauticus, Desulfomicrobium, and Desulfuromonas in the soured Ivishak well compared to the non-soured well. In the non-soured Ivishak sample, several taxa affiliated with Thermoanaerobacter and Halomonas predominated. Archaea were not detected in the deepest reservoirs. Functional group taxa differed in relative abundance among reservoirs, likely reflecting differing thermal and/or geochemical influences

Metagenomics reveals sediment microbial community response to Deepwater Horizon oil spill

The Deepwater Horizon (DWH) oil spill in the spring of 2010 resulted in an input of ∼4.1 million barrels of oil to the Gulf of Mexico; >22% of this oil is unaccounted for, with unknown environmental consequences. Here we investigated the impact of oil deposition on microbial communities in surface sediments collected at 64 sites by targeted sequencing of 16S rRNA genes, shotgun metagenomic sequencing of 14 of these samples and mineralization experiments using (14)C-labeled model substrates. The 16S rRNA gene data indicated that the most heavily oil-impacted sediments were enriched in an uncultured Gammaproteobacterium and a Colwellia species, both of which were highly similar to sequences in the DWH deep-sea hydrocarbon plume. The primary drivers in structuring the microbial community were nitrogen and hydrocarbons. Annotation of unassembled metagenomic data revealed the most abundant hydrocarbon degradation pathway encoded genes involved in degrading aliphatic and simple aromatics via butane monooxygenase. The activity of key hydrocarbon degradation pathways by sediment microbes was confirmed by determining the mineralization of (14)C-labeled model substrates in the following order: propylene glycol, dodecane, toluene and phenanthrene. Further, analysis of metagenomic sequence data revealed an increase in abundance of genes involved in denitrification pathways in samples that exceeded the Environmental Protection Agency (EPA)'s benchmarks for polycyclic aromatic hydrocarbons (PAHs) compared with those that did not. Importantly, these data demonstrate that the indigenous sediment microbiota contributed an important ecosystem service for remediation of oil in the Gulf. However, PAHs were more recalcitrant to degradation, and their persistence could have deleterious impacts on the sediment ecosystem

The Eighteenth Data Release of the Sloan Digital Sky Surveys: Targeting and First Spectra from SDSS-V

The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Comment: Accepted to ApJ

The eighteenth data release of the Sloan Digital Sky Surveys : targeting and first spectra from SDSS-V

The eighteenth data release of the Sloan Digital Sky Surveys (SDSS) is the first one for SDSS-V, the fifth generation of the survey. SDSS-V comprises three primary scientific programs, or "Mappers": Milky Way Mapper (MWM), Black Hole Mapper (BHM), and Local Volume Mapper (LVM). This data release contains extensive targeting information for the two multi-object spectroscopy programs (MWM and BHM), including input catalogs and selection functions for their numerous scientific objectives. We describe the production of the targeting databases and their calibration- and scientifically-focused components. DR18 also includes ~25,000 new SDSS spectra and supplemental information for X-ray sources identified by eROSITA in its eFEDS field. We present updates to some of the SDSS software pipelines and preview changes anticipated for DR19. We also describe three value-added catalogs (VACs) based on SDSS-IV data that have been published since DR17, and one VAC based on the SDSS-V data in the eFEDS field.Publisher PDFPeer reviewe