Disinfection byproducts (DBPs) have attracted extensive attention due to their adverse health effects such as genotoxicity, mutagenicity, and carcinogenicity. With higher formation potential and occurrence in all disinfection processes, trihalomethanes (THMs) are one of the most significant DBPs. Since ions are universally existent by natural or anthropogenic input to groundwater or surface water, the effects of ions (Ca²⁺, Mg²⁺, NH⁺₄, As³⁺, Fe³⁺, Al³⁺, Cu²⁺, and F⁻) on THM formation during chlorination in bromide-containing water were investigated in the present study. The results showed that THM formation and speciation were substantially influenced by the ions, but the degree and mechanisms of effects were critically dependent on the ion species. THM formation was inhibited by Ca²⁺, Mg²⁺, As³⁺, and NH⁺₄ significantly, and was enhanced by Fe³⁺, Cu²⁺, and Al³⁺. The mechanisms of influence of the above ions were interpreted for complexation, consumption, and catalysis. Furthermore, due to the higher Br⁻ concentration, CHBr₃ was the dominant species in THMs.

One of the limitations compromising the utilization of enzymes for the remediation of phenolic wastewaters is enzyme activity loss during the treatment. Some surface active additives have the potential to protect enzymes and, thus, improve their performance. In this study, the removal of bisphenol A from synthetic wastewater samples by laccase has been studied in the presence of rhamnolipid biosurfactant (RL), polyethylene glycol (PEG), Triton X-100, cetyltrimethylammonium bromide (CTAB), and sodium dodecylbenzenesulfonate (SDBS). The results demonstrated that the addition of 1 ppm RL provides the highest removal rate and removal extent of BPA. In the case of PEG and Triton X-100, the results showed that both additives have almost similar positive effects on the enzymatic remediation of BPA. However, unlike RL, the positive effects of PEG and Triton X-100 were appreciable only at higher concentration (i.e., 25 ppm). On the other hand, the addition of the two ionic surfactants (SDBS and CTAB) resulted in a negative effect on the enzyme activity and, thus, the remediation of BPA, demonstrating the undesirable interactions of these ionic surfactants with laccase. The negative effect of the charged additives was more pronounced for the case of the positively charged additive (i.e., CTAB).

In present work, mustard straw, an abundantly available agricultural residue in various parts of globe, is used to prepare a low-cost activated carbon by chemical activation using phosphoric acid. Response surface methodology is employed for optimization of adsorption of methylene blue dye onto mustard straw-activated carbon (MSAC). Central composite design is employed to evaluate the effect of three production variables namely activation temperature (400–800 °C), activation time (60–120 min), and impregnation ratio (2–7), on adsorption capacities of activated carbon to maximize methylene blue dye removal from its aqueous solution. Among the three process variables, activation time showed prominent effect on the response whereas the effect of activation temperature was relatively less significant on adsorption capacity of MB. The optimum conditions obtained for MSAC are activation temperature, 768 °C; activation time, 60 min; and impregnation ratio, 4.2, which leads to 198 mg g⁻¹ adsorption capacity of methylene blue. The model predicted and experimental value for response were highly comparable. Characterization of MSAC was done using several analytical techniques such as Fourier transform infrared spectroscopy and field emission scanning electron microscopy techniques, and reusability up to five adsorption-desorption cycles was tested. The results showed that MSAC obtained has highly porous structure comparable with activated carbon obtained from other biomass feed stocks.

This paper investigated the organic matter removal in waste stabilization ponds (WSP) based on ten full-scale wastewater treatment plants (WWTP) located in Rio Grande do Norte, Northeast Brazil. Although many systems are operating at high organic loading rates, in some cases, over 1000 kg BOD₅ ha⁻¹ d⁻¹, the ponds promoted satisfactory removals of biochemical oxygen demand (BOD₅) and chemical oxygen demand (COD). The first-order removal rates (k) for BOD₅ and COD were obtained by assuming the ideal hydraulic patterns of completely mixed and plug-flow models. The k values proved to be a function of physical and operational parameters that affect fluid movement in a pond. The increase in the organic loading rate caused an increase in first-order removal rates. Moreover, increasing the ratio between hydraulic retention time (HRT) and depth (H) led to a reduction in k values. This information can be adapted into predictive models to be applied in WSP designs with similar characteristics. In comparison with the empirical equations reported in the literature, these models lead to removal rates more appropriate to the local reality.

Incomplete removal of organic pollutants during wastewater treatment is one of the main routes to introduce micro-pollutants into the environment. This group of pollutants includes, among others, UV filters. Commonly used UV filters are 2-ethylhexyl 4-methoxycinnamate (EHMC) and 2-ethylhexyl 4-(dimethylamino)benzoate (ODPABA). Due to the lipophilic character, these compounds can accumulate in sludge. The effects of activated sludge on the removal of EHMC and ODPABA from wastewater have been investigated in this study. It was shown that both UV filters tend to accumulate in the sludge. The concentration of UV filters in sludge increased with the increase of activated sludge dose and time of process. It was checked whether EHMC and ODPABA were transformed in activated sludge. A gas chromatograph coupled with a mass spectrometry detector (GC-MS) was used to identify products. In the case of EHMC, ethylhexyl alcohol (EHA) and the Z-EHMC isomer were identified. Methyl-4-aminobenzoic acid (MPABA) was identified as ODPABA degradation product. Elimination of EHMC and ODPABA from wastewater mainly proceeds by adsorption of these pollutants in the sludge. Filters present in wastewater and sludge undergo transformations.

The effect of nickel in the adsorption of N-acetyl-p-aminophenol (paracetamol) on a metal-organic frameworks (MOFs) type MIL-101(Cr) was studied. The incorporation of Ni to MOFs adsorbent was carried out by impregnation and adjusted to give a 4.00 wt.% Ni. The adsorbents were characterized by specific surface area (SSA), surface acidity techniques, electrophoretic migration (EM), thermogravimetric analysis (TGA), and scanning electron microscope (SEM) and were tested by the adsorption of paracetamol solutions. The results showed that the Ni particles were well dispersed throughout the MIL-101(Cr) crystal increasing the acid strength and the density of acid site values in the MOFs surface. The increase in adsorption capacity of MIL-101(Cr) when Ni was incorporated can be attributed to the availability of metal atoms as adsorption centers that can adsorb the paracetamol by electronic retro-donation through π-type complexing.

The present study focuses on the simultaneous analysis of metallic species and radionuclide data from January 2009 to December 2011 in the dust deposited on filters in Málaga (Spain). Some metallic elements (Ca, Fe, K, Mg, Na, Zn, Pb, Cu, Ni) and radionuclides (⁷Be and ²¹⁰Pb) have been determined by inductively coupled plasma-mass spectroscopy and gamma spectrometry, respectively. For this analysis, daily variation of PM₁₀ mass concentration was additionally recorded at the nearest station belonging to the regional atmospheric pollution monitoring network. The comparison between ²¹⁰Pb, elemental lead, and PM₁₀ mass concentration reveals a different time variation for raining months, and an increase in the ²¹⁰Pb/Pb ratio indicates local sources of the particulate mass. Principal components analysis (PCA) applied to the datasets and calculation of enrichment factors relative to soil and seawater reveal that the atmospheric aerosol chemistry in this area of the Mediterranean is mostly influenced by crustal and marine sources rather than anthropogenic ones.

Neonicotinoids are a popular class of systemic insecticides registered for use in over 120 countries. Recent global water surveys have found neonicotinoid insecticides in waterbodies adjacent to agricultural fields. The presence of neonicotinoids in surface waters raises the concern of the potential risk of exposure to non-target aquatic species, with relevance for both free-living and parasitic taxa. The susceptibility of aquatic free-living parasitic stages to the lethal effects of neonicotinoids may influence the prevalence and intensity of host infection, and their availability as prey for a variety of organisms (e.g., fish, invertebrates). We examined the effects of two commonly used neonicotinoids on the survival of free-living infectious stages (cercariae) from two trematode (flatworm) species (Diplostomum sp. and Haematoloechus sp.). We found that exposure to commercially formulated imidacloprid and thiamethoxam, individually and in a binary mixture, had no significant effect on cercarial survival for either species at environmentally relevant concentrations. Further study is required to understand if the ability of the surviving cercariae to infect the next host in their life cycle is compromised in the presence of neonicotinoids, or if host defenses are compromised, as changes in parasite infectivity or host susceptibility could influence infection dynamics and have community- and ecosystem-level implications.

The main objective of this paper is to estimate the impact of foreign research and development (R&D) spillovers on pollution and renewable energy consumption (RE). We choose as proxies for R&D and for foreign R&D spillovers, resident patents (RP) and non-resident patents (NRP), respectively. We use annual data for the USA spanning the period 1980–2016. We show the presence of a long-run relationship between NRP, RP, RE, fossil energy consumption (FE), net energy imports (NEI), gross domestic product (GDP), and carbon dioxide (CO₂) emissions. There are long-run unidirectional Granger causalities running from all considered variables to economic growth. There are short-run unidirectional causalities running from NEI to all considered variables except RP and GDP, from GDP to RP and RE, from FE to RE, and from carbon emissions to RE. By using the autoregressive distributed lag approach, several long-run elasticities are evaluated. In particular, RP increases carbon emissions, whereas NRP reduces it. Both RP and NRP have a positive impact on RE and GDP. RP and NRP seem to be complementary activities, and RE reduces NEI. Therefore, the US authorities should encourage the use of NRP because of their beneficial effect on pollution, home innovation, renewable energy consumption, and economic growth.

Secondary pollution resulting from shoot death is a difficult problem that complicated the application of wetland plants for water purification in northern wetlands. Phalaris arundinacea, a perennial herb with an obviously declining stage, or senescence, is a species that is often selected for water purification in Northern China; however, whether it reduces the secondary pollution risk via nitrogen (N) and phosphorus (P) accumulation during senescence or not remains unclear. To investigate this question, an experiment was conducted with containerized plants during the winter of 2016, after roughly half the leaves on the plants had withered. The experimental observations and analyses were conducted within 0, 2, 4, 6, and 8 weeks of the initiation of senescence. Results revealed that leaves continued to wither and shoot death occurred during weeks 4 to 6 and 8 to 10, respectively. However, no significant differences occurred in fresh biomass or in N and P accumulations of a single plant during senescence. The root biomass, root weight per volume, and total N content increased significantly, while total P content remained stable when leaves withered, respectively. H⁺-ATPase, a key enzyme for ion transportation, decreased after the leaves withered. However, root activity, evaluated by absorption surface per root volume, remained stable, and percentage of fine root length (diameter < 1 mm) increased significantly during senescence. In conclusion, the root activity and morphology enables P. arundinacea to accumulate N and P during senescence, which makes it a good choice for water purification in northern wetlands.