Total Organic Carbon Loading Research Articles

Nitrogen removal from wastewater using simultaneous nitrate reduction and anaerobic ammonium oxidation in single reactor

The effects of C/N ratio and total organic carbon (TOC) loading on nitrogen removal through simultaneous nitrate reduction and anaerobic ammonium oxidation in a single reactor were examined. Granular sludge taken from a methane fermentation reactor was placed in an upflow reactor and supplied with synthetic wastewater containing nitrate at a C/N ratio of 1 to grow heterotrophic denitrifying bacteria. When nitrogen removal ratio reached 30%, anammox sludge attached to nonwoven-carrier was added into the same reactor and then ammonia was added to the synthetic wastewater. Nitrogen removal ratio was markedly increased to 80-94%. In this system, nitrogen removal ratio was affected by C/N ratio and TOC loading, not by the amount of granular sludge. A stable isotopic analysis using 15N-labeled nitrate showed that N2 gas was formed by anammox reaction.

Effects of tidal flat reclamation on sediment quality and hypoxia in Isahaya Bay

1. Ariake Bay, which is located in western Japan, has a large tidal range (>6 m) and a vast tidal flat (200 km2). In the early 1990s, the government-managed Isahaya Reclamation Project began in the western part of Ariake Bay. A 16-km2 area of tidal flat in the inner part of Isahaya Bay was destroyed through reclamation and separated from the sea by a dyke, which created land and a freshwater reservoir. 2. Since the initiation of the project, fishery yields around Isahaya Bay have dramatically decreased. The objective of this study was to clarify the relationship between the work associated with the Isahaya Reclamation Project and the recent environmental deterioration in Ariake Bay, with references to present sediment thickness and organic matter content, and hypoxic water distributions in Isahaya Bay. 3. The organic matter load from the reservoir has increased since the initiation of the reclamation project and has been associated with a thick layer of fine sediment at the bottom of Isahaya Bay. The thickness of fine sediment and the total organic carbon content were higher in Isahaya Bay than in the freshwater reservoir. 4. Based on measurements in August 2001, hypoxic water spread widely in and around Isahaya Bay; the lowest dissolved oxygen (DO) concentration (0.53 mg L−1) was observed just outside the dyke. An analysis based on a two-layered box model using data obtained in August 2001 showed that the DO consumption rate in the bottom layer was high (0.61 mg O2 L−1 day−1), and that 22–41% of the total organic carbon load needed to induce the hypoxic water was derived from the reclamation area. 5. Our findings strongly suggest that enclosed seas may suffer from eutrophic and hypoxic conditions because of their low seawater-exchange rate. A comprehensive conservation programme and environmental assessment including physical and material transport processes in the system is needed to manage the environment of the enclosed sea. Copyright © 2005 John Wiley & Sons, Ltd.

Total organic carbon load on the Gulf of Finland from its Russian catchment area

Total organic carbon load on the Gulf of Finland from its Russian catchment area

Simulating dynamic load of naturally occurring TOC from watershed into a river

Naturally occurring total organic carbon (TOC) is an important feature of stream water quality. This study investigates the dynamic load of TOC from the deep creek watershed into the lower St. Johns River (LSJR), FL, USA, using numerical simulations and field measurements. An existing St. Johns River watershed assessment model for simultaneous loading of nutrients from watersheds into rivers is modified to include the TOC component for the purpose of this study. Three simulation scenarios (i.e., daily, monthly, and annually) are performed to estimate the dynamic load of TOC in response to rainfall events. Simulations show that rainfall events have decisive effects on TOC loads from the Deep Creek watershed into the LSJR. In general, the highly frequent the rainfall events occur, the higher the TOC loads into the river. Simulations also illustrate that effects of rainfall events on daily changes of TOC are minimal in winter, but are profound in late summer. Results suggest that TOC load into the river is not only a rainfall-driven but also a temperature-driven biological process.

RELATIONSHIP BETWEEN ALLOCHTHONOUS DOC CONCENTRATION AND A SPECIFIC UV254 ABSORBANCE (SUVA) AT A MESO-STRATIFIED RESERVOIR

This study aimed to identify the origin of DOC loading, by which the extent of SUVA representing of humic content or aromaticity of natural organic matter, NOM concentration in lake, could be determined and the effect of hydraulics conditions on the dynamic behavior of SUVA in the Daecheong reservoir, Korea. The type of Daecheong reservoir was meso-stratified as the ratio of inflow rate to reservoir capacity, α, was under 10 but it was temporally classified into intermediate type during storm season by heavy rainfall. Over 90% of total DOC loading attributed to allochthonous sources in upstream and it concentrated in storm season. While, autochthonous DOC by production of algae in Daecheong reservoir appeared only in short period of algal bloom. And the proportion of autochthonous DOC to total organic carbon loading varied significantly depending on spatial locations but was not significant. The extent of SUVA in lake water depth was severely deteriorated by inflow rate and the location of intrusion of storm flows into lake layer during storm event because density of inflow storm water is usually heavier than that of the surface water. It has been found that SUVA in Daecheong reservoir strongly attributed to allochthonous DOC from upstream watershed.

Calcium–Nom Loading onto Gac

This research evaluated how to minimize calcium (Ca) loading onto granular activated carbon (GAC) by adjusting pH and/or adding coagulants. Batch tests used raw water samples from New Castle, Pa. Total organic carbon (TOC) ranged from 4.0 to 5.3 mg/L. Variations in Ca loading reflected variability in natural organic matter composition between samples. For most samples, 5 mg/L of iron coagulant (as Fe) diminished Ca loading by 200–600 mg Ca/kg GAC—an 18–75% drop. In batch tests at constant pH with no coagulant and variable GAC doses, Ca loading increased linearly with TOC loading indicating that Ca and TOC adsorbed into GAC together. The ratio of Ca to TOC loaded onto GAC decreased with decreasing pH or increasing Fe. This showed that H+ or Fe(III) could displace the Ca that loaded with TOC and that utilities could diminish Ca loading by slightly depressing pH and/or by using moderate coagulant dosages.

Trihalomethane Precursor Model for Lake Youngs, Washington

A mathematical model is developed to estimate trihalomethane formation potential (THMFP) in Lake Youngs, Wash. The model simulates both seasonal trends and spatial variations. The model kinetic framework includes total organic carbon (TOC), THMFP, chlorophyll a, zooplankton, Secchi disk depth, dissolved oxygen, dissolved TDP, and total phosphorus (TP). Calculated THMFP concentrations are dependent on external watershed TOC loading, algal cell densities, and TOC associated with extracellular products. Model performance is evaluated by comparison of calculated results with measured data from Lake Youngs. Analyses illustrate how THMFP concentrations in the raw water supply change as a function of watershed TP and TOC loading. A general assessment considers the role of watershed land-use control, reservoir management, alternative treatment technologies, and the operation of the water supply distribution system in complying with finished drinking water standards for THM.

Charcoal analysis in marine sediments

A technique is described for measuring charcoal in small samples (5 mg) of marine sediments to quantify the contribution of charcoal to the total organic carbon loading of marine sediments. Charcoal is measured as elemental carbon by gas chromatography after acidification with hot concentrated nitric acid in situ within aluminum sample cups to remove calcium carbonate and refractory carbon such as coal, pollen, and humic acids. The in situ acidification eliminates sample loss during sequential decarboxylation and oxidation and provides a precise (±2.2% of the measured value) and rapid (~50 analyses per week per analyst) means to measure charcoal in marine sediments. The absolute detection limit of the charcoal determinations is 0.70 µg C (3 times mean blank value) and the relative detection limit is 0.01%.

Investigation of organic aerosol sampling artifacts in the los angeles basin

Filter collection of particulate organic carbon is complicated by adsorption and volatilization sampling artifacts which inhibit attempts to accurately assess aerosol concentrations. Insight into the adsorption artifact can be gained by considering that adsorption on sampling filters is conceptually similar to gas-particle partitioning with the filter acting as a model aerosol. We found that significant adsorption of gas-phase organic compounds occurs on quartz fiber filters, and the presence of typical loadings of particulate material on the sampling filter does not significantly affect the magnitude of the adsorption artifact. Also placing a Teflon filter upstream of a pair of quartz fiber filters has no effect on total organic carbon loadings on the final quartz fiber filter, but adsorbed organic carbon loadings are much higher on quartz fiber filters behind Teflon filters than on quartz fiber filters behind quartz fiber filters. Organic carbon sampled from the atmosphere is unlikely to attain equilibrium between that in the gas phase and that adsorbed on the quartz fiber sampling filter. As a result, a quartz fiber filter behind a quartz fiber filter is exposed to a lower gas-phase concentration than a quartz fiber filter behind a Teflon filter. This explains the difference between Teflon-quartz and quartz-quartz backup filters and suggests that Teflon-quartz backup filters provide a better estimate of adsorbed vapor on quartz fiber front filters than do quartz-quartz backup filters. Under typical sampling conditions adsorption is the dominant artifact in the sampling of particulate organic carbon, and longer sampling periods reduce the percentage of collected material that is adsorbed vapor.

A study of the partitioning and sorptive behaviour of butyltins in the aquatic environment

AbstractThis study was designed to investigate the partitioning and sorptive behaviour of tributyltin(TBT), and its degradation products dibutylitin (DBT) and monobutyltin (MBT), in the aquatic environment. Factorial experiments were undertaken to determine the importance of pH and particulate matter concentration in the sorption of butyltin compounds to solid phases. Results indicate that in freshwaters MBT, and to a lesser extent TBT, will be partitioned towards the particulate phase, whereas DBT exhibits a 50:50 partitioning between particulate and solution phases. In estuarine waters, whilst MBT will almost exclusively sorb on to particulates, TBT will be predominantly in the solid‐phase fractions but 10–30% may remain in solution. DBT, in contrast, is solubilized in estuarine waters. A more detailed investigation of TBT sorption and particulate matter concentration was undertaken using adsorption isotherms on different sediment types. The results from batch isotherm tests plotted according to the Freundlich adsorption model revealed that TBT adsorption varied with sediment type, increasing in the order sandy‐silt < silty‐sand < silty‐clay. TBT sorption was found to be reversible, indicating that contaminated sediments may release TBT to overlying waters following sediment distrubance. Interstitial water partitioning studies indicate that TBT predominates in the particulate phase with partition coefficients for TBT higher than for DBT and MBT. The TBT partition coefficient in interstitial waters appears to be related to total organic carbon loadings.

Total organic carbon emissions from municipal incinerators

Total carbon (TC), carbonate carbon (CC) and total organic carbon (TOC) were determined in bottom ash, filter dust and flue gas of Swiss municipal solid waste (MSW) incinerators. The highest TOC load was found in the bottom ash (2–3 g kg 1 MSW), followed by the filter dust (0.1–1.0 g kg −1 MSW) and the flue gas (0.05–0.3 g kg −1 MSW). The composition and behaviour of the bulk of TOC in these products is not yet known. In order to minimize the risk of leaching organic substances as well as metals due to biological, chemical and physical reactions of the products of incineration in a landfill, it is suggested the incineration process be optimized towards complete combustion.

Total Organic Carbon Emissions From Municipal Incinerators

Total carbon (TC), carbonate carbon (CC) and total organic carbon (TOC) were determined in bottom ash, filter dust and flue gas of Swiss municipal solid waste (MSW) incinerators. The highest TOC load was found in the bottom ash (2-3 g kg-1 MSW), followed by the filter dust (0.1-1.0 g kg-1 MSW) and the flue gas (0.05-0.3 g kg-1 MSW). The composition and behaviour of the bulk of TOC in these products is not yet known. In order to minimize the risk of leaching organic substances as well as metals due to biological, chemical and physical reactions of the products of incineration in a landfill, it is suggested the incineration process be optimized towards complete combustion.

Nitrogen, Phosphorus, and Organic Carbon Cycling in an Arctic Lake

Budgets for nitrogen, phosphorus, and organic carbon in Toolik Lake, Alaska, were assembled from data collected during 1977–81. The annual total organic carbon (TOC), total nitrogen (TN), and total phosphorus (TP) loads to the Sake were 8557, 290, and 4.64 mmol∙m−2. Inlet streams were the major source of nutrients to the lake, as direct precipitation provided only 1, 2, and 5%, respectively, of the annual TOC, TN, and TP loads to the lake. Up to 30% of the annual N and P inputs to the lake from riverine sources occurred during the first 10 d of stream flow following breakup when cold water temperatures and snow-covered ice limited primary production. Due to the short water renewal time (0.5 yr), efficiency of nutrient retention was poor and 90, 82, and 70% of the annual TOC, TN, and TP inputs to the lake were discharged at the outlet stream. Regeneration within the water column supplied 40–66% and 68–78% of the N and P necessary for measured primary production. Yearly accumulation rates for C, N, and P in the sediment were about 220, 21.0, and 1.75 mmol∙m−2. Phosphorus remineralized within the sediment was completely retained due to adsorption onto Fe oxide minerals in the oxidizing surface layer. Annual rates of release of C and N to the overlying water column were 110 and 11.5–22.2 mmol∙m2. Mass balance considerations showed no serious errors in estimates of any terms of the annual sediment and water column N, P, and organic C budgets.

PHYSICAL-CHEMICAL APPROACHES FOR THE ENVIRONMENTALLY SOUND DISPOSAL OF AN OIL SHALE RETORT WATER

ABSTRACT The extraction of shale oil produces relatively large volumes of polluted process water. These waters contain large concentrations of organic and inorganic pollutants as well as environmentally significant amounts of trace materials. These substances either individually or in combination can be highly toxic to environmental systems. This paper addresses a suggested cleanup sequence designed to remove specific pollutants and to detoxify these waters. Hot gas stripping, followed by activated carbon adsorption and reverse osmosis removed over 93 percent of the total organic carbon load while also reducing the.toxicity of the resultant effluent as measured by a standard technique. Depending upon the ultimate use of these waters, the suggested treatment sequence or its individual components could be employed at a pilot or commercial scale retorting facility.