This paper presents a real-time control strategy based on the derivative of the oxi-reduction potential (ORP) values for nitrogen removal via nitrite in a sequencing batch reactor (SBR) fed with effluent from an anaerobic sequencing batch reactor (ASBR) treating dairy wastewater. The developed control strategy optimized the length of aerobic and anoxic phases without external carbon source addition. Firstly, a fixed interval length for aeration period was used in the SBR cycle to promote the nitrogen removal; however, this strategy did not allow the proper alternation of anoxic and aerobic conditions, and thus effective removal of nitrogen was not verified. After that, the real-time control strategy was implemented, and the end of nitrification and denitrification processes was determined when the derivative of the oxi-reduction potential (ORP) was close to zero. This strategy provided a removal of 92.2 ± 9.7 and 63.9 ± 19.0% for concentrations of TKN-N and Nt-N, respectively, which were well above those found for the open-loop system—43.8 ± 21.6 and 26.5 ± 26.2% for the removal of TKN-N and Nt-N, respectively.

Hydrothermally altered rocks are frequently encountered when tunnels are constructed in Hokkaido, Japan. High concentraions of hazardous elements, such as arsenic (As), are often released from these rocks into the surrounding environments. Therefore, the rocks are considered potentially hazardous waste. This article describes the effects of water content and oxygen (O₂) concentration in relation to additional layer(s), i.e., surface covering and bottom adsorption layers, on As leaching by using laboratory columns with water content and O₂ concentration sensors. The results show that the use of additional layer(s) has a significant effect on lowering As migration. This was due not only to the adsorption capacity of As by the adsorption layer but also to the water content and O₂ concentration inside the rock layer. The accumulation of pore water was increased in the rock layer in cases with additional layer(s), which resulted in lower O₂ concentration in the rock layer. Consequently, the leaching of As by the oxidation of As-bearing minerals in the rock layer was reduced. Moreover, a longer water-resident time in the rock layer may induce precipitation of Fe oxy-hydroxide/oxide. These results suggest that the geochemical conditions of the rock layer affect As leaching and migration.

The aim of this study was to investigate phosphate removal using crushed concrete granules (CCGs). The CCGs were thermally treated at different temperatures (300, 500, 700, and 900 °C) for 3 h under anoxic conditions. The results showed that CCGs thermally treated at 700 °C (700TT-CCGs) were the most effective for the removal of phosphate. The equilibrium adsorption data fitted well the Langmuir isotherm model with a maximum phosphate adsorption capacity of 21.522 mg/g, higher than that of granular adsorbents in the literature. In pH experiments, phosphate adsorption by 700TT-CCGs decreased as initial pH increased from 3 to 5, but sharply increased above pH 5 (final pH 9.1), which was favorable for the formation of calcium phosphate precipitate. The effect of competing anions on phosphate adsorption follows the order: HCO₃⁻ > SO₄²⁻ > NO₃⁻, which is consistent with the reverse order of the shared charge. Column experiments showed no breakthrough of phosphate in the column packed with half 700TT-CCGs and half sand for over 300 h. This study demonstrates that CCGs can be used for phosphate removal from aqueous solution after thermal treatment, which is a simple and cheap way to improve the phosphate removal capacity of CCGs.

The objectives of the present study are to isolate thiosulfate-degrading bacterium and optimize its degradative conditions including temperature, pH, and thiosulfate concentrations required for bioremediation purposes. A heterotrophic thiosulfate-degrading bacterial strain DT was successfully isolated from saline soil and identified as Altererythrobacter sp. based on its physicochemical properties and 16S rDNA sequence analysis. It was a naturally occurring methionine auxotrophic strain that utilized only peptone, yeast extract, or several amino acids as the sole carbon source. Altererythrobacter sp. DT degraded thiosulfate via a distinctive disproportionation reaction which was characterized by accumulation of sulfate and elemental sulfur at a molar ratio of 1:1. Optimal conditions for both bacterial growth and thiosulfate metabolism were 25–30 °C and pH 6, respectively. In a fed-batch treatment system receiving liquid polysulfide wastewater, a high degradation rate of 407.3 mg S₂O₃²⁻/(L h) and an elemental sulfur yield of nearly 50% were achieved for immobilized DT cells, indicating great potential of strain DT for future application in the treatment of and microbial production of elemental sulfur from thiosulfate-bearing industrial wastewater.

The incidence of Legionella and Acanthamoeba spp. was correlated to microbial indicator analysis and physico-chemical characteristics of rainwater harvested from catchment areas constructed from galvanized zinc, Chromadek®, and asbestos, respectively. Quantitative PCR (qPCR) analysis indicated that no significant difference (p > 0.05) in copy numbers of Legionella spp. and Acanthamoeba spp. was recorded in tank water samples collected from the respective roofing materials. However, significant positive Spearman (ρ) correlations were recorded between the occurrences of Legionella spp. gene copies vs. nitrites and nitrates (p = 0.05) in all tank water samples. Significant positive correlations were also established between Acanthamoeba spp. vs. barium (p = 0.03), magnesium (p = 0.02), sodium (p = 0.02), silicon (p = 0.05), arsenic (p = 0.03), and phosphate (p = 0.01), respectively. Additionally, while no significant correlations were observed between Legionella spp. vs. the indicator bacteria (p > 0.05), positive correlations were observed between Acanthamoeba spp. vs. total coliforms (p = 0.01) and Acanthamoeba spp. vs. Escherichia coli (p = 0.02), respectively. Results obtained in the current study thus indicate that the incidence of Acanthamoeba and Legionella spp. in harvested rainwater was not influenced by the roofing material utilized. Moreover, it is essential that the microbial quality of rainwater be assessed before this water source is implemented for potable and domestic uses as untreated harvested rainwater may lead to legionellosis and amoebae infections.

Dairy cattle manure has been implicated as a major source of fecal contamination in non-point source agricultural runoff in watersheds. Four different dairy farms in central Texas, each utilizing a different dairy manure management practice, in the Leon River watershed were sampled for E. coli using EPA Method 1603, with a percentage of isolates genotyped and phylotyped using the Clermont quadruplex PCR method. E. coli concentration was reduced as manure moved through the management process with tiered management systems lowering concentration the most. E. coli genotypes showed no correlation with sampling season or management practice. The highest percentage of unique genotypes was observed in dairy 2, which consisted of a settling basin then lagoon. One genotype was seen across all dairies and composed 15% of all genotypes characterized. E. coli phylotypes showed no seasonal or management practice trend. B1 was the most common phylotype isolated from all dairies and time periods, which was expected. Potentially pathogenic phylotypes were rarely observed, which could indicate isolation from pathogenic E. coli introduction. Dairy manure management practices that separate solid from liquid waste reduced E. coli concentrations the most based on these results.

Wastewater treatments can eliminate or remove a substantial amount of pharmaceutical active compounds (PhACs), but there may still be significant concentrations of them in effluents discharged into surface water bodies. Beirolas wastewater treatment plant (WWTP) is located in the Lisbon area and makes its effluent discharges into Tagus estuary (Portugal). The main objective of this study is to quantify a group of 32 PhACs in the different treatments used in this WWTP. Twelve sampling campaigns of wastewater belonging to the different treatments were made in 2013–2014 in order to study their removal efficiency. The wastewaters were analysed by solid phase extraction (SPE) and ultra-performance liquid chromatography coupled with tandem mass detection (UPLC–MS/MS). The anti-diabetics were the most frequently found in wastewater influent (WWI) and wastewater effluent (WWE) (208 and 1.7 μg/L, respectively), followed by analgesics/antipyretics (135 μg/L and < LOQ, respectively), psychostimulants (113 and 0.49 μg/L, respectively), non-steroidal anti-inflammatory drugs (33 and 2.6 μg/L, respectively), antibiotics (5.2 and 1.8 μg/L, respectively), antilipidemics (1.6 and 0.24 μg/L, respectively), anticonvulsants (1.5 and 0.63 μg/L, respectively) and beta blockers (1.3 and 0.51 μg/L, respectively). A snapshot of the ability of each treatment step to remove these target PhACs is provided, and it was found that global efficiency is strongly dependent on the efficiency of secondary treatment. Seasonal occurrence and removal efficiency was also monitored, and they did not show a significant seasonal trend.

Diclofenac (hereafter DCF) is an extensively used anti-inflammatory drug; therefore, it is found in many sewage treatment plant effluents and it is one of the most usually reported environmental pharmaceutical contaminants. In this work, the degradation of diclofenac in pure water under UV light was studied, and the influence of some variables, such as humic acids (HA), nitrate anions (NO₃⁻) and titanium dioxide (TiO₂) on DCF photodegradation was investigated. The experimental activity was carried out in a batch reactor of 100 mL equipped with fixed UV light of 254 nm and an irradiation intensity of 400 mJ/m². Diclofenac initial concentration was equal to 10 mg/L in pure water, and its removal was evaluated by varying HA concentration in the range 10–20 mg/L and NO₃⁻ concentration in the range 25–50 mg/L. Furthermore, the heterogeneous catalysis with TiO₂ (1–50 mg/L) was studied. Temperature in all experiments was kept constant at 20 °C. Experimental results show that while HA have a significant influence on DCF photodegradation, nitrate and titanium dioxide seem to be ineffective, at least in the tested conditions. Finally, DCF photolysis modelling was carried out and a pseudo-first-order kinetic model was used.

In this study, the degradation of benzene by the means of an optimized surface/packed-bed hybrid discharge (SPBHD) plasma combined with γ-Al₂O₃-supported MO ₓ (M = Ag, Mn, Cu, or Fe) catalysts in post plasma-catalysis (PPC) system. The effects of Ag loading amount and gas hourly space velocity (GHSV) for plasma-catalysis degradation of benzene have been systematically investigated. The experimental result showed that the benzene degradation was improved and the mineralization process was greatly enhanced towards total oxidation after the combination of plasma with all MO ₓ /γ-Al₂O₃ catalysts. The AgO ₓ /γ-Al₂O₃ catalyst exhibited the best catalytic activity in benzene degradation than the other catalysts in PPC system. The highest benzene degradation efficiency of 96% and CO ₓ selectivity of 99% can be obtained for AgO ₓ /γ-Al₂O₃ catalyst with optimum Ag loading amount and GHSV of 15% and 22,856 h⁻¹, respectively. Time course of benzene degradation during PPC process indicated that the plasma-induced catalytic activity of AgO ₓ /γ-Al₂O₃ catalyst was temporary rather than lasting over a period after the plasma off. FT-IR analysis results revealed that the intermediate products (such as CO, HCOOH) and unwanted by-products (O₃ and NO ₓ) generated in plasma process could be significantly inhibited by PPC process with AgO ₓ /γ-Al₂O₃ catalyst.

PCDD/F-contaminated soil of a coastal region formerly involved in the production of pentachlorophenol (PCP) in Tainan City in southern Taiwan, has drawn wide concern throughout the island. This main goal of this study was to find an effective and environmentally friendly means of removing PCDD/Fs from its contaminated fields. We performed a soil washing experiment with fish extract using a combination of ultrasonification and mechanical double-blade stirring. The experiments were conducted under ambient temperature, at a soil/liquid ratio of 1:2.5, 700 rpm, and over a short duration. This combined method using fish extract removed 94.12% of the pollutant in moderately contaminated soils (5 washing cycles) and 94.51% in highly contaminated soils (10 washing cycles), mostly via particle collision and penetration. These findings highlight the benefits of PCDD/F partitioning between the particles and fish oil extract. This study is the first to use fish oil extract, a natural solvent, to treat soils highly contaminated with dioxins. Because fish oil extract is rich in non-toxic bio-surfactants (e.g., alcohols, acids, ketones, etc.), it may be used in this process to improve bioavailability and bioactivity of the soil making bio-attenuation and full remediation safer and more efficient.