Petroleum hydrocarbons in the bilge water of small fishing vessels are continuously released into the environment. The bilge water samples usually contained low amounts of oil-degrading bacteria; therefore, this study examines application of polyurethane foam (PUF)-immobilized Gordonia sp. JC11, a known lubricant-degrading bacterial inoculum, for the treatment of bilge water. Batch microcosm experiments showed that the PUF-immobilized bacteria were more efficient at removing oil than indigenous microorganisms and were able to remove approximately 40-50 % of the boat lubricant (1,000 mg L-1). The immobilized PUF samples rapidly adsorbed oil from the bilge water inside a small fishing vessel; however, the uninoculated PUF contained more oil than the inoculated PUF at most time points. The hydrocarbon components were also different when comparing inoculated and uninoculated PUF. These results indicate that the oil accumulated inside the PUF containing immobilized bacteria was being degraded by the Gordonia sp. JC11. However, these bacteria gradually die off after repeated oil exposure, and it is suggested that PUF-immobilized cells be replaced at timed intervals. This technique is considered simple and cheap; thus, it could be used to reduce chronic oil pollution from the release of bilge water. © 2013 Springer Science+Business Media Dordrecht.

Chlorine is the most commonly used chemical for water and wastewater disinfection worldwide, and it reacts with both ammonia and dissolved organic nitrogen. Using the salicylate spectrophotometric method, effects of glycine on the classic breakpoint chlorination are studied using glycine as a surrogate for dissolved organic nitrogen. The results show that the shape of the breakpoint chlorination curve with glycine was analogous to that of water without glycine. Increasing the glycine concentration moves the chlorination breakpoint curve to the right, demonstrating that more chlorine must be added to replace the chlorine consumed by glycine and yield the desired residual active chlorine concentration. At the peak of the chlorination breakpoint curve, both NH₂Cl and mono-chlorinated organic chloramine reach their maximum. The Cl₂/N ratio of the peak is linearly related to the glycine concentration, and our calculations indicate that the maximum of mono-chlorinated organic chloramine formation by glycine chlorination occurs at a stoichiometric ratio of 1:1; the same as that for chlorinating ammonia to NH₂Cl. The distribution of NH₂Cl and organic chloramines is controlled by [Gly]/[NH₃-N]. At the breakpoint, ammonia and glycine are completely oxidized by chlorine, which leads to chlorine depletion. The stoichiometric ratio for the complete oxidation of glycine was 3:1, larger than that for complete oxidation of ammonia (2:1). For the different stoichiometric ratio in reaction of oxidation of ammonia and glycine, the sum of ammonia and glycine cannot be used as a chlorine dosage control parameter. The chlorine control method involving ammonia and glycine for chlorine and chloramination process is established.

Diesel exhaust particulate matter contains many semivolatile organic compounds (SVOCs) of environmental and health significance. This study investigates the composition, emission rates, and measurement integrity of 25 SVOCs, including polycyclic aromatic hydrocarbons (PAHs), nitro-PAHs (NPAHs), and diesel biomarkers hopanes and steranes. Diesel engine particulate matter (PM), generated using an engine test bench, three engine conditions, and ultralow sulfur diesel (ULSD), was collected on borosilicate glass fiber filters. Under high engine load, the PM emission rate was 0.102 g/kWh, and emission rates of ΣPAHs (10 compounds), ΣNPAHs (6 compounds), Σhopanes (2 compounds), and Σsteranes (2 compounds) were 2.52, 0.351, 0.02-2 and 1 μg/kWh, respectively. Storage losses were evaluated for three cases: conditioning filters in clean air at 25 C and 33 % relative humidity (RH) for 24 h, storing filter samples (without extraction) wrapped in aluminum foil at 4 C for up to 1 month, and storing filter extracts in glass vials capped with Teflon crimp seals at 4 C for up to 6 months. After conditioning filters for 24 h, 30 % of the more volatile PAHs were lost, but lower volatility NPAHs, hopanes and steranes showed negligible changes. Storing wrapped filters and extracts at 4 C for up to 1 month did not lead to significant losses, but storing extracts for 5 months led to significant losses of PAHs and NPAHs; hopanes and steranes demonstrated greater integrity. These results suggest that even relatively brief filter conditioning periods, needed for gravimetric measurements of PM mass, and extended storage of filter extracts, can lead to underestimates of SVOC concentrations. Thus, SVOC sampling and analysis protocols should utilize stringent criteria and performance checks to identify and limit possible biases occurring during filter and extract processing. © 2013 Springer Science+Business Media Dordrecht.

Inorganic forms of mercury (Hg) can be converted by natural processes into methylmercury, a highly potent neurotoxin that can bioaccumulate in food chains and pose a risk to human health. Although Hg can enter aquatic environments through direct deposition, the predominant source derives from complex terrestrial cycling in nearby ecosystem vegetation and soils. Here we assess the spatial distribution of soil and litterfall Hg within two paired catchments of the Shenandoah National Park: the northwest-facing North Fork Dry Run (NFDR) and the southeast-facing Hannah Run (HR) catchments. Litterfall Hg concentrations were not significantly different between the NFDR and HR catchments. This may be attributable to the speciation of Hg (gaseous elemental Hg) that is involved in leaf-level accumulation. Significant differences in soil organic-layer Hg concentrations were observed between the two study catchments, with NFDR soils having roughly 50 % higher Hg concentrations than those from HR. These differences can be explained by differences in soil N content (and to a lesser extent soil C content) between catchments, as both elements exert a strong control of the amount of Hg bound in soils. We found no evidence that topographic aspect contributes to the spatial variability of soil Hg concentrations in these paired catchments, but did detect an influence from elevation. Soils located near ridges in mountainous catchments can contain relatively high Hg concentrations due to (1) lower turnover rates in soil organic matter pools, (2) enhanced deposition, and (3) limited mobilization of Hg from those areas.

Both groundwater flow and mercury concentrations in pore water and seawater were quantified in the groundwater seeping site of the Bay of Puck, southern Baltic Sea. Total dissolved mercury (HgTD) in pore water ranged from 0.51 to 4.90 ng l⁻¹. Seawater samples were characterized by elevated HgTD concentrations, ranging from 4.41 to 6.37 ng l⁻¹, while HgTD concentrations in groundwater samples ranged from 0.51 to 1.15 ng l⁻¹. High HgTD concentrations in pore water of the uppermost sediment layers were attributed to seawater intrusion into the sediment. The relationship between HgTD concentrations and salinity of pore water was non-conservative, indicating removal of dissolved mercury upon mixing seawater with groundwater. The mechanism of dissolved mercury removal was further elucidated by examining its relationships with both dissolved organic matter, dissolved manganese (Mn II), and redox potential. The flux of HgTD to the Bay of Puck was estimated to be 18.9 ± 6.3 g year⁻¹. The submarine groundwater discharge-derived mercury load is substantially smaller than atmospheric deposition and riverine discharge to the Bay of Puck. Thus, groundwater is a factor that dilutes the mercury concentrations in pore water and, as a result, dilutes the mercury concentrations in the water column.

N-Nitrosodimethylamine (NDMA) is recently defined as one of nitrogenous disinfection by-products with high carcinogenicity and can be frequently detected in finished water. The decomposition of NDMA in water using nanoscale zero-valent iron (NZVI) in the presence of aluminum and iron salts was investigated in this paper. The results showed that some salts can enhance the removal of NDMA by commercial NZVI in the order of Al(SO) >> AlCl > FeSO > NaSO ≈ NZVI alone, and the highest NDMA removal was 87.3 % in the presence of Al(SO). NDMA removal varied with the addition of Al(SO), NZVI dosage, initial NDMA concentration, solution pH, and temperature. The reduction of NDMA increased with the dosage of Al(SO) and NZVI, which follows a pseudo-first-order kinetics model. The removal of NDMA by NZVI was higher in acidic pHs than in alkaline ones, and the highest removal was found at pH 5. Higher reaction temperature can improve the removal of NDMA and reduce the reaction time. Based on the total nitrogen balance, most nitrogen of NDMA was converted to ammonium and dimethylamine.

Sepiolite reveals as a low-cost and efficient adsorbent for the adsorption of caffeine from aqueous solutions. The characterization of this material was carried out by N₂ adsorption–desorption at 77 K, Fourier transform infrared spectroscopy, thermogravimetric analysis, and electronic microscopy. Initially, batch adsorption experiments were developed in order to determine the equilibrium time and the adsorption isotherm of the system. Pseudo–first-order, Elovich equation, pseudo–second-order, and intra-particle diffusion models were applied to the experimental data to determine the adsorption kinetics. In continuous adsorption, the influence of several operation conditions (initial caffeine concentration, volumetric flow rate, and mass of adsorbent) on the shape of breakthrough curves and the mass transfer resistance was evaluated. Experimental data were fitted to the bed-depth service-time model bed-depth service-time (BDST). Through the calculation of the adsorption, parameters as breakthrough time or caffeine removal percentage can be concluded that the removal of this compound from aqueous solutions by adsorption in sepiolite beds is an alternative technique to the current methods, in order to eliminate this micropollutant.

A comparative long-term study of three subsurface horizontal-flow (HF) constructed wetlands (CW) treating winery wastewater was carried out. The water depth for HF1 was 0.3 m, while the depth for HF2 and HF3 was 0.6 m, respectively. Hydraulic loading rate ranged from 7 to 93 mm/d, while surface loading rates fell into the following ranges: 4–85 g COD/m²·d, 2–49 g BOD₅/m²·d and 0.5–6 g TSS/m²·d. The percentage of biological oxygen demand (BOD₅) removal clearly decreased when influent concentration increased, while surface removal rate increased and reached a maximum of approximately 8 g BOD₅/m²·d removed in the range of 10–20 g BOD₅/m²·d fed, depending on the CW depth. HF1 showed a worse performance than the other units, appearing to be more affected by high influent concentrations. Solids accumulation on gravel media, hydraulic conductivity and gas emissions were monitored over the 2.8 years of operation.

In this study, chemical oxidation was applied to treat three contaminated sediments. All the sediments were contaminated with mineral oil, polycyclic aromatic hydrocarbons and heavy metals and had an organic matter content ranging from 2.4 to 7.6 %. The natural oxidant demand of the sediments was determined during treatment with two different types of oxidants (potassium permanganate and sodium persulfate), and the effect of these oxidants on the heavy metal release and on the microbial community was investigated. The natural oxidant demands of the sediments under persulfate treatment were lower (30–100 g kg⁻¹) than the ones treated with permanganate (50–450 g kg⁻¹). Cr was released during the application of permanganate whereas Zn and Pb were released under persulfate treatment. qPCR results showed that permanganate and persulfate, both at a concentration of 150 g kg⁻¹, caused a decrease (2 log units) in the number of 16S rRNA gene of total bacteria in the sediment having the lowest organic matter content. However, the total ATP, considered as a biomarker for microbial activity, was below detection limit in all sediments in the presence of at least 150 g kg⁻¹ oxidant. Only permanganate induced a shift in the structure of the microbial community.

A total of three fungal isolates from samples collected at spent wash disposal area were screened for their ability to degrade melanoidin. Distillery molasses spent wash was decolorized, and its chemical oxygen demand (COD) was reduced in immobilized fungal bioreactor (IFB) in the absence of carbon and nitrogen source using fungal mycelia of Aspergillus oryzae MTCC 7691. Fungal mycelia immobilized on baggase packed in a glass column under a batch-wise mode (1) effected removal of 75.71 +/- 0.12 % color, 51.0 +/- 0.13 % biological oxygen demand (BOD), 86.19 +/- 2.56 % COD, and 49.0 +/- 0.12 % phenolic pigments of distillery spent wash up to 25 days at 30 degrees C, while free fungal mycelia resulted in removal of 63.1 +/- 0.16 % color, 27.74 +/- 0.14 % BOD, 76.21 +/- 1.62 % COD, and 37.32 +/- 0.17 % phenolic pigments of distillery spent wash using shake flask, (2) manganese peroxidase (MnP) activity was highest (1.55 +/- 0.01 U ml(-1) min(-1)) in immobilized fungi, followed by lignin peroxidase (0.65 +/- 0.01 U ml(-1) min(-1)) and laccase activity (0.9 +/- 0.01 CU ml (1) min (1)), (3) accumulative MnP activity was highly correlated with (r=0.9216) spent wash decolorization and (r=0.7282) reduction of phenolic pigments, suggesting the presence of MnP activities in bioremediation of spent wash and (4) degradation of spent wash was confirmed by high-performance thin layer chromatography and gas chromatography-mass spectrometry analysis. Measurement of chlorophyll a content of Chlorella species cultivated on treated spent wash effluent obtained from immobilized fungal bioreactor was 5.16 +/- 0.71 mu g ml(-1) compared with 1.306 +/- 0.017 +/-mu g ml(-1) obtained with untreated spent wash. Thus, this work may provide a reasonable alternative for cost-effective bioremediation of distillery spent wash using immobilized A. oryzae on baggase fibers.