The coffee agro-industry generates a large volume of wastewater that is notable for its high organic strength as well as its color content. Due to the seasonal nature of the harvest (3–4 months per year), this particular industrial waste needs a treatment method that is both reliable and fast (in terms of start-up time). As part of investigating a system capable of treating a coffee wastewater, this research evaluated four electrochemical advanced oxidation processes (EAOPs) using boron-doped diamond (BDD) electrodes. The processes were anodic oxidation (AO), anodic oxidation with electrogenerated H₂O₂(AO-H₂O₂), electro-Fenton (EF), and photoelectro-Fenton (PEF). Experimental conditions were as follows: 40 mA cm⁻²current density (all EAOPs), 0.3 mmol Fe²⁺L⁻¹(Fenton systems), 300 mL air min⁻¹(AO-H₂O₂, EF, PEF), and 500 μW cm⁻²UV irradiation (photo-Fenton systems). The performance of the four EAOP treatment methods (in terms of color and organic carbon removal) was compared against two conventional chemical oxidation methods, namely, Fenton and photo-Fenton. The research indicated that the four EAOPs were better at removing color (89–93 %) and total organic carbon (TOC) (73–84 %) than the respective chemical Fenton (58 and 4.8 %) and photo-Fenton (61 and 7 %) methods. The trend in performance was as follows: AO-H₂O₂ > AO > PEF ≈ EF. It appeared that the ferrous iron reagent formed a dark-colored complex with some coffee components, diminishing the effect of Fenton reactions. In addition, the dark color of the wastewater limited the effect of light in the UV-Fenton processes. Analysis showed that acceptable levels of Fe²⁺(0.3 mmol L⁻¹) and energy (0.082–0.098 kWh g⁻¹TOC) were required by the EAOPs after 4-h treatment time. In conclusion, the use of electrochemical methods (equipped with BDD electrodes) seems a promising method for the effective treatment of coffee wastewaters.

Principal component analysis (PCA) was performed on chemical data of two sediment cores from an urban freshwater lake in Copenhagen, Denmark. X-ray fluorescence (XRF) core scanning provided the underlying datasets on 13 variables (Si, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Rb, Cd, and Pb). Principal component analysis helped to trace geochemical patterns and temporal trends in lake sedimentation. The PCA models explained more than 80 % of the original variation in the datasets using only two or three principal components. The first principal component (PC1) was mostly associated with geogenic elements (Si, K, Fe, Rb) and characterized the content of minerogenic material in the sediment. In the case of both cores, PC2 was a good descriptor emphasized as the contamination component. It showed strong linkages with heavy metals (Cu, Zn, Pb), disclosing changing heavy-metal contamination trends across different depths. The sediments featured a temporal association with contaminant dominance. Lead contamination was superseded by zinc within the compound pattern which was linked to changing contamination sources over time. Principal component analysis was useful to visualize and interpret geochemical XRF data while being a straightforward method to extract contamination patterns in the data associated with temporal elemental trends in lake sediments.

The annual atmospheric deposition rates of²¹⁰Po and²¹⁰Pb were determined in İzmir, Turkey. The samples were collected from 18 November 2008 to 17 November 2009. The annual²¹⁰Po deposition flux was determined as 44.1 ± 3.0 Bq m⁻² year⁻¹, while²¹⁰Pb flux was calculated as 73.1 ± 4.4 Bq m⁻² year⁻¹using bulk collectors. The monthly deposition fluxes of²¹⁰Po and²¹⁰Pb were correlated with the amount of precipitation. The activity concentrations of the samples were found to vary between 5.7 ± 1.1 and 167.1 ± 7.5 mBq L⁻¹, with an average value of 41.2 ± 1.9 mBq L⁻¹for²¹⁰Po; and between 5.3 ± 0.6 and 265.7 ± 10.8 mBq L⁻¹, with an average value of 67.3 ± 2.7 mBq L⁻¹for²¹⁰Pb. The activity ratios of²¹⁰Po/²¹⁰Pb in the samples ranged from 0.16 to 3.39, with an average value of 0.80. During the course of the study,²¹⁰Po enhancement from both natural and anthropogenic sources was observed.

Different cases of bioremediation technique were experimentally investigated here for decontaminating light non-aqueous phase liquid (LNAPL)-polluted groundwater collected from Panipat oil refinery situated in Haryana, India. Natural biodegradation of toluene, the selected LNAPL, was studied first under different varying substrate concentrations at room temperature (21.6 ± 0.3 °C). Biostimulation was then studied by mixing the polluted groundwater with a primary treated domestic wastewater for providing nutrients and other supplementary components to the native microbial population. For studying the remaining cases, small-scale wetland having plants of Canna generalis was developed in the laboratory with and without the presence of toluene in the rhizosphere. The wetland system in the presence of toluene was used here for developing the pre-grown microbial cultures to enhance the degradation rate of the LNAPL (bioaugmentation). The plant-assisted biostimulation was studied in the third case by adding the polluted groundwater with the root zone water of the wetland system developed without the presence of toluene. In the fourth case, the biostimulation was coupled with the bioaugmentation strategy by mixing the groundwater with the root zone water of the wetland system developed in the presence of toluene. A comparative account of these four different bioremediation techniques was prepared for their respective rates of biodegradation, duration of lag phases, and the total time of degradation. It was observed that the plant-assisted bioremediation techniques had better performance over the natural biodegradation and biostimulation methods of the considered LNAPL. The plant-assisted biostimulation coupled with the bioaugmentation technique needed almost no acclimatization time and accelerated the rate of degradation almost twofold compared to the natural bioremediation and, hence, is proved to be the best one among the other bioremediation techniques for decontaminating the LNAPL-polluted groundwater. The results of the conducted experiments can be used to obtain vital information on framing the engineered bioremediation planning for LNAPL-contaminated sites.

The variability of levels of fecal indicator bacteria (FIB) and a human-associated genetic marker (HF183) during wet and dry weather conditions was investigated at two urban coastal watersheds in Southern California: Santa Monica Canyon channel (SMC) and Ventura Harbor, Keys, and Marina. Seventy-eight to 86 % of the samples collected from SMC sites exceeded standard water quality standards for FIB (n = 59 to 76). At SMC, HF183 was present in 58 % of the samples (n = 78) and was detected at least once at every sample site. No individual site at SMC appeared as a hotspot for the measured indicators, pointing to a likely chronic issue stemming from urban runoff in wet and dry weather. In Ventura, the Arundell Barranca, which drains into Ventura Harbor and Marina, was a source of FIB, and HF183 was most frequently detected off of a dock in the Marina. Rainfall significantly increased FIB levels at both SMC and Ventura; only at Ventura did HF183 detection increase with wet weather. Sample locations that were high in FIB were geographically distinct from the sites that were high in HF183 in Ventura, which supports the importance of measuring host-associated parameters along with FIB in chronically impaired watersheds to guide water quality managers in pollution remediation efforts.

A novel high-capacity phosphate removal adsorbent of graphene nanosheets (GNS) supported lanthanum hydroxide (LaOH) is prepared. The phosphate adsorption performance for GNS-LaOH is examined by a batch adsorption method from aqueous solutions. The Freundlich and Langmuir models are used to simulate the sorption equilibrium, which reveal that the Langmuir model has a better correlation with the experimental data. The maximum adsorption capacity is calculated to be 41.96 mg/g. The kinetic data from the adsorption of phosphate is suggested as the pseudo-second-order model, and the multi-linearity adsorption process is observed in the intraparticle diffusion model, indicating that a chemisorption process is dominant in the adsorption of phosphate. The phosphate adsorption mechanism is explored by analyzing the Fourier transform infrared spectroscopy (FT-IR) and the relationship between the adsorption amount and the pH value of phosphate solution. Ligand exchange and electrostatic and Lewis acid–base interactions are determined to be three main factors for phosphate adsorption.

The majority of consumer products used today are comprised of some form of plastic. Worldwide, almost 280 million t of plastic materials are produced annually, much of which ends up in landfills or the oceans (Shaw and Sahni Journal of Mechanical and Civil Engineering 46–48, 2014). While plastics are lightweight, inexpensive, and durable, these same qualities can make them very harmful to wildlife, especially once they become waterborne. Once seaborne, plastics are most likely found circulating in one of five major ocean gyres: two in the Pacific, one in the Indian, and two in the Atlantic. These ocean garbage patches are not solid islands of plastic; instead, they are a turbid mix of plastics (Kostigen 2008; Livingeco 2011). Recent research conducted on the surfaces of the Great Lakes has identified similar problems (Erikson et al. Marine Pollution Bulletin, 77(1), 177–182, 2013). A growing concern is that once plastics reach the wild, they may cause entanglement, death from ingestion, and carry invasive species. Several cutting edge technologies have been piloted to monitor or gather the plastics already in our environments and convert them back into oil with hopes to reduce the damage plastics are causing to our ecosystems.

Removal of hexavalent chromium by precipitation from wastewater has received increasing interest in recent years. This study described the behavior of chromium and iron coprecipitation mediated by Acidithiobacillus ferrooxidans DC in an artificial simulated acid environment. In four parallel groups with the different concentrations of chromium(VI) (30, 60, 90, 120 mg/L), the precipitation efficiencies of chromium were enhanced uniformly by A. ferrooxidans DC. But chromium coprecipitation efficiency reduced as the initial chromium concentration increasing at the early stage. Especially in the 30 and 60 mg/L chromium groups, the maximum precipitation efficiency of chromium was improved from 56.22, 55.01 to 75.72, 74.37 % on the fourth day. Additionally, the characteristics of the precipitates were analyzed by x-ray diffraction (XRD), scanning electron microscope (SEM), and Fourier transform infrared spectroscopy (FTIR). Results showed that the precipitates were mainly present as jarosites and A. ferrooxidans was conducive to producing precipitates with good crystalline form and uniform dispersion with pH decrease, redox potential (ORP) increase, and iron oxidation. It can be concluded that the chromium could be incorporated into the jarosites through a certain biochemical reaction such as structural substitution, which shows a potential to remove chromium from wastewater by the bio-coprecipitation.

The application of combined electrochemical and photochemical techniques for the degradation of real textile effluent is presented. It is demonstrated that the simultaneous use of both techniques, in conjunction with in situ generation of free chlorine and its subsequent photolysis, is a promising technique for removing color and chemical oxygen demand (COD) from effluents. Crucially, the combination of electrochemical and photochemical techniques leads to lower quantities of chlorine-containing degradation by-products being produced and no overall increase in toxicity. Over the treatment times studied, up to 65 % less chloride-containing degradation by-products are formed while at the same time greater rates of color and COD removal are achieved.

Polychlorinated dibenzo-p-dioxins and dibenzofurans (dioxins) are pollutants of significant global concern, and China is one of the main dioxin-emitting countries in the world. Facing increasing dioxin concentrations in the environment, the Chinese government set a mandatory goal of 10 % reduction in the rate of emission intensity by 2015 in an attempt to reduce dioxin emissions. In the study presented here, we estimated the outputs (or waste disposal capacities) of the four key dioxin-emitting industries in China in 2015. We then estimated that the total amount of dioxins released from these four industries was approximately 8.0 kg toxic equivalent (TEQ)/year. These results indicate that dioxin emissions in China have not decreased under the current plan, and the plan needs to be adjusted. A goal for a decrease in the total dioxin emissions in China is proposed, and several policies and measures aimed at allowing the target dioxin emission decrease to be achieved are recommended.