Food waste and sewage sludge are the most abundant and problematic organic wastes in any society. Mixture of these two wastes may provide appropriate substrate condition for dark fermentative biohydrogen production based on synergistic mutual benefits. This work evaluates continuous hydrogen production from the cosubstrate of food waste and sewage sludge to verify mechanisms of performance improvement in anaerobic sequencing batch reactors. Volatile solid concentration and mixing ratio of food waste and sludge were adjusted to 5 % and 80:20, respectively. Five different hydraulic retention times (HRT) of 36, 42, 48, 72, and 108 h were tested using anaerobic sequencing batch reactors to find out optimal operating condition. Results show that the best performance was achieved at HRT 72 h, where the hydrogen yield, the hydrogen production rate, and hydrogen content were 62.0 mL H₂/g VS, 1.0 L H₂/L/day, and ~50 %, respectively. Sufficient solid retention time (143 h) and proper loading rate (8.2 g COD/L/day as carbohydrate) at HRT 72h led to the enhanced performance with better hydrogen production showing appropriate n-butyrate/acetate (B/A) ratio of 2.6. Analytical result of terminal-restriction fragment length polymorphism revealed that specific peaks associated with Clostridium sp. and Bacillus sp. were strongly related to enhanced hydrogen production from the cosubstrate of food waste and sewage sludge.

Despite the growing popularity of ecological restoration approach, data on primary succession on toxic post-mining substrates, under site environmental conditions which considerably differ from the surrounding environment, are still scarce. Here, we studied the spontaneous vegetation development on an unusual locality created by long-term and large-scale fluvial deposition of sulphidic tailings from a copper mine in a pronouncedly xerothermic, calcareous surrounding. We performed multivariate analyses of soil samples (20 physical and chemical parameters) and vegetation samples (floristic and structural parameters in three types of occurring forests), collected along the pollution gradients throughout the affected floodplain. The nature can cope with two types of imposed constraints: (a) excessive Cu concentrations and (b) very low pH, combined with nutrient deficiency. The former will still allow convergence to the original vegetation, while the latter will result in novel, depauperate assemblages of species typical for cooler and moister climate. Our results for the first time demonstrate that with the increasing severity of environmental filtering, the relative importance of the surrounding vegetation for primary succession strongly decreases.

The present work describes the aqueous phase removal of 4-chloro-2-methylphenoxyacetic acid herbicide by rice husk ash (RHA) using batch and packed bed adsorption techniques. The effects of dosage, initial concentration, time, pH, temperature, and particle size of adsorbent in batch compared with effects of influent concentration, flow rate, and bed height in packed bed were studied. The particle size effect reveals that the removal is dependent on chemical composition (silica and carbon content) together with BET surface area of RHA. The aptness of Langmuir isotherm to batch data indicates the favorable adsorption whereas that of Temkin isotherm informs the heterogeneous nature of RHA. The kinetics of adsorption follows the pseudo-second order and Elovich models while thermodynamics of process indicates the exothermic adsorption. Among the models applied in packed bed study, the deactivation kinetic, Yoon–Nelson and bed depth service time (BDST) models are suitable to explain the packed bed adsorption. The adsorption capacity of RHA in packed bed study is found greater than that in batch. The adsorption capacity of RHA determined by the BDST model is 3019 mg/L for 90 % saturation of bed. The adsorption capacity of RHA based on weight is ∼2.3 times and that based on surface area is ∼55.55 times greater than that of granular activated carbon.

In this study, the efficiency of Moringa stenopetala seed extract was compared with alum and M. stenopetala-alum hybrid coagulant to remove Direct Red 23 azo dye from textile wastewater. The effects of parameters such as pH, coagulant dose, type of salt used for the extraction of coagulant and initial dye concentration on dye removal efficiency were investigated. Moreover, the existing functional groups on the structure of M. stenopetala coagulant (MSC) were determined by Fourier transform infrared spectroscopy, and the morphology of sludge produced by MSC, alum, and hybrid coagulant was characterized by scanning electron microscopy. Ninhydrin test was also used to determine the quantity of primary amines in the MSC and Moringa oleifera coagulant (MOC). According to the results, with increasing the coagulant dose and decreasing the initial dye concentration, dye removal efficiency has increased. The maximum dye removal of 98.5, 98.2, and 98.3 % were obtained by using 240, 120, and 80 mg/L MSC, alum and hybrid coagulant at pH 7, respectively. The results also showed MSC was much more effective than MOC for dye removal. The volume of sludge produced by MSC was one fourth and half of those produced by alum and hybrid coagulant, respectively. Based on the results, hybrid coagulant was the most efficient coagulant for direct dye removal from colored wastewater.

Tetrabromobisphenol A (TBBPA) is one of the most commonly used flame retardants and has become an environmental contaminant worldwide. More data on the basic characteristics of TBBPA are needed to better understand and used to describe its environmental fate. The aim of this study is to investigate the degradation of TBBPA with different degrees of bromination under the atmospheric different environments. TBBPA was removed quickly due to the strong oxidizing ability of ozone in the atmospheric environment. The half-life of TBBPA was approximately 2.5 h when the ozone concentration was 0.3 mg L⁻¹. The degradation reaction rates of TBBPA increase with increasing ozone concentration but decreased with increasing soil depth. When the ozone concentration was 10 mg L⁻¹, the removal rate of TBBPA reached 90.37 % at the soil surface after 2 h. Under UV irradiation, TBBPA was removed quickly, and the photodegradation reactions were faster than with solar irradiation. The conditions of alkaline soil and high ground temperature in the summer were both contributors to the degradation of TBBPA. These results could facilitate the improvement of waste treatment designs and could lead to better predictions of the outcome of TBBPA in the environment.

The application of organic amendments into heavy metal contaminated soil is considered as an environmentally friendly technique to promote the potential of phytoremediation. A pot experiment was carried out to evaluate the effect of humic substances on growth, cadmium (Cd) accumulation and phytostabilization potential of the mining ecotype (ME) and the corresponding non-mining ecotype (NME) of Athyrium wardii (Hook.) grown in Cd-contaminated soils. The addition of the humic substances demonstrated great promotion for the growth and Cd uptake of ME. Both plant biomass and Cd concentration significantly increased with the increasing application of the humic substances up to 100 g kg⁻¹, beyond which no significant change of underground part biomass and Cd concentrations in underground part of A. wardii was observed. The maximum Cd concentration in underground part of ME was 180 mg kg⁻¹ when 150 g kg⁻¹ humic substances were applied. The ME showed greater Cd accumulation capability in underground part (0.47–0.68 mg plant⁻¹) than that of NME (0.27–0.45 mg plant⁻¹). Increasing bioaccumulation coefficient (BCF) values of A. wardii was observed with increasing application of the humic substances. The BCF values of ME were higher than those of NME. However, the use of the humic substances exhibited little impact on translocation factors (TFs) of ME, and the TF values of ME were less than NME. Furthermore, the application of the humic substances improved the remediation factors (RFs) of A. wardii. The RF values in underground part of ME ranging from 0.73 to 0.91 % were apparently higher than those of NME. These results indicated that the humic substances can be a potential candidate for enhancing the phytostabilization of A. wardii grown in Cd-contaminated soils.

Chromophoric dissolved organic matter (CDOM) plays an important role in aquatic systems, but high concentrations of organic materials are considered pollutants. The fluorescent component characteristics of CDOM in urban waters sampled from Northern and Northeastern China were examined by excitation-emission matrix fluorescence and parallel factor analysis (EEM-PARAFAC) to investigate the source and compositional changes of CDOM on both space and pollution levels. One humic-like (C1), one tryptophan-like component (C2), and one tyrosine-like component (C3) were identified by PARAFAC. Mean fluorescence intensities of the three CDOM components varied spatially and by pollution level in cities of Northern and Northeastern China during July–August, 2013 and 2014. Principal components analysis (PCA) was conducted to identify the relative distribution of all water samples. Cluster analysis (CA) was also used to categorize the samples into groups of similar pollution levels within a study area. Strong positive linear relationships were revealed between the CDOM absorption coefficients a(254) (R ² = 0.89, p < 0.01); a(355) (R ² = 0.94, p < 0.01); and the fluorescence intensity (F ₘₐₓ) for the humic-like C1 component. A positive linear relationship (R ² = 0.77) was also exhibited between dissolved organic carbon (DOC) and the F ₘₐₓ for the humic-like C1 component, but a relatively weak correlation (R ² = 0.56) was detected between DOC and the F ₘₐₓ for the tryptophan-like component (C2). A strong positive correlation was observed between the F ₘₐₓ for the tryptophan-like component (C2) and total nitrogen (TN) (R ² = 0.78), but moderate correlations were observed with ammonium-N (NH4-N) (R ² = 0.68), and chemical oxygen demand (CODMₙ) (R ² = 0.52). Therefore, the fluorescence intensities of CDOM components can be applied to monitor water quality in real time compared to that of traditional approaches. These results demonstrate that EEM-PARAFAC is useful to evaluate the dynamics of CDOM fluorescent components in urban waters from Northern and Northeastern China and this method has potential applications for monitoring urban water quality in different regions with various hydrological conditions and pollution levels.

The aim of this study was to link the concentrations of particulate matter with an aerodynamic diameter below 2.5 μm (PM₂.₅) and associated heavy metals with occurrence of wheezing and hospitalizations due to wheezing in 111 children who live near metallurgical plants in Targoviste City, Romania. A group of 72 children with high levels of immunoglobulin E (IgE) and eosinophils, as well as frequent wheezing episodes, was geolocated on digital thematic maps. Monitoring campaigns and medical assessments were performed over two consecutive years (2013–2014). The multiannual average concentrations of PM₂.₅ ranged from 4.6 to 22.5 μg m⁻³, up to a maximum value of 102 μg m⁻³. Significant correlations (p < 0.01) were observed between the locations of the children with respiratory issues and the PM₂.₅ multiannual average (r = 0.985) and PM₂.₅ maximum (r = 0.813). Fe, Ni, Cd, and Cr were the main marker elements of the emissions from steel production and metal-working facilities in the Targoviste area. The results support the hypothesis that increased PM₂.₅ levels directly influence wheezing symptom and asthma attacks in the analyzed group. IgE, eosinophils, and wheezing episodes may be considered key indicators with which to evaluate the adverse effects of PM₂.₅ air pollution on children’s health.

India has a giant jute-producing basket which produces considerable quantity of toxic jute mill waste (JMW). Conversely, report on usability potential of JMW is rather scanty. The present study illustrates the efficiency of vermicomposting in bioconversion of JMW for agricultural use. Various combinations of JMW, cow dung, and vegetable waste were fed to Metaphire posthuma in vermireactors. Rapid increment of earthworm count, body weight, and cocoon production was evidenced. Total organic carbon and pH reduction was noteworthy, but N, P, and K availability, formation of stable humic acid C, fulvic acid C, and microbial biomass C substantially increased due to vermicomposting. FTIR spectroscopy confirmed a higher stability of vermicomposted JMW over the composted product. A significant decline in heavy metal concentration (Cr, Pb, Fe, and Zn) in the vermicomposted JMW further establishes the potential of vermicomposting with M. posthuma in successful conversion of the toxic JMW into valuable product.