The rheology of digested sludge affects the flow hydrodynamics, dewaterability, and the polymer consumption in wastewater treatment plants. The rheological characteristics of digested sludge are highly dependent on changes in total solid concentration, temperature, and polymer dose. Hence, this study aims at investigating the impacts of total solid concentration, temperature, and polymer dose on the rheological characteristics and the dewaterability of digested sludge. Investigating the relationship between rheological and physicochemical characteristics of sludge can also serve as a tool to optimize essential process parameters. Different homogenized digested sludge samples were subjected to rheological measurement on rotational stress-controlled rheometer equipped with Peltier concentric cylinder system. The shear stress–shear rate and viscosity–shear rate curves were then developed before and after polymer conditioning at various temperatures and solid concentrations. Different rheological model were fitted to the shear stress–shear rate and viscosity–shear rate rheograms, and the model with the best fitting and more practical significance was selected to determine key rheological parameters. The relationship between dewaterability and digested sludge rheology was also developed. The rheological characteristics of digested sludge during polymer conditioning and flocculation process was significantly affected by temperature and solid concentration; hence, polymer dose can be reduced by operating the dewatering process at optimum temperature condition and varying the polydose as a function of the total solid concentration and viscosity of the digested sludge. The dewaterability as measured in capillary suction time (CST) improved with increasing polymer dose up to 12 kg/t DS but further increase in polymer dose resulted in the deterioration of the dewaterability due to overdosing.

In order to clarify how cadmium (Cd) chemical forms in planta relate to the genotype difference in Cd accumulation of spinach (Spinacia oleracea L.), two low-Cd and two high-Cd cultivars were compared under a hydroponic experiment with two concentrations of Cd (8.98 or 44.71 μmol Cd L⁻¹). The concentrations of phosphorus in the hydroponic system were also adjusted to two levels (0.5 and 1.0 mmol L⁻¹) to investigate the influence of phosphorus on the forms and accumulation of Cd in the tested cultivars. Average Cd concentrations in shoots were 8.50−10.06 mg kg⁻¹ for high-Cd cultivars and 6.11–6.64 mg kg⁻¹ for low-Cd cultivars a under lower Cd treatment and were as high as 24.41–31.35 mg kg⁻¹ and 19.65–25.76 mg kg⁻¹, respectively, under a higher treatment. Phosphorus significantly decreased Cd accumulation in the tested cultivars, and the effect had superiority over the cultivar alternation under higher Cd stress. Cadmium in the NaCl-extractable fraction of the plant tissues showed the greatest relationship to genotype difference of Cd accumulation. The difference in the capacity to binding Cd into F HAc, F HCₗ, or F Rₑₛᵢdᵤₑ was another important mechanism involving in the genotype difference in Cd accumulation of spinach. Among them, average proportion of Cd in F HAc in low-Cd cultivars was higher than that in high-Cd cultivars in association with the effect of phosphorus.

During SO₂ removal from flue gas by coal slurry scrubbing, coal pyrite sulfur can be simultaneously reduced. But satisfactory coal pyrite conversion cannot be achieved under normal scrubbing conditions. In the present work, aluminum oxide and aluminum sulfate were tested as additives to enhance the leaching of coal pyrite during SO₂ removal in a bubbling reactor. It was found that adding aluminum oxide or aluminum sulfate into the coal slurry could increase the coal pyrite conversion and SO₂ removal efficiency. The leaching process could be described by the reaction-controlled shrinking core model. Based on the facts that both aluminum and ferric irons can exist in aqueous solution in the form of sulfate and hydroxide complex ions, it was deduced that the attraction between the oppositely charged ions might promote the coal pyrite leaching reactions, suppress the formation of passive Fe solid products, and increase the concentration of soluble complexed Fe(III) which also acted as coal pyrite oxidant.

Trimethylamine (TMA) is a volatile organic compound which causes not only unpleasant odor but also health concerns to humans. The average emission of TMA from food and fishery industries is 20.60 parts per billion (ppb) and emission from the gas exhausters is even higher which reaches 370 parts per million (ppm). In order to select the best plant TMA removal agent, in this study, 13 plants were exposed to 100 ppm of TMA and the remaining TMA concentration in their system was analyzed by gas chromatography (GC). Furthermore, plant metabolites from the selected plant were identified by gas chromatography-mass spectrometry (GC-MS). The result showed that Euphorbia milii was the most superior plant for TMA removal and could absorb up to 90 % of TMA within 12 h. E. milii absorbed TMA via leaf and stem with 55 and 45 % uptake efficiency, respectively. Based on its stomatal movement during the exposure to TMA, it was implied that the plant switched the photosynthetic mode from crassulacean acid metabolism (CAM)-cycling to CAM and CAM-idling. The switching of photosynthetic mode might reduce the stomata role in TMA absorption. Fatty acids, alkanes, and fatty alcohols in the plant leaf wax were also found to contribute to TMA adsorption. Leaf wax, stomata, and other leaf constituents contributed 58, 6, and 36 %, respectively, of the total TMA absorption by the leaf. The analysis and identification of plant metabolites confirmed that TMA was degraded and mineralized by E. milii.

The uptake of polybrominated diphenyl ethers (PBDEs) by carrot and lettuce was investigated. Degradation of PBDEs in soil in the absence of the plants was discarded. Different carrot (Nantesa and Chantenay) and lettuce (Batavia Golden Spring and Summer Queen) varieties were grown in fortified or contaminated compost-amended soil mixtures under greenhouse conditions. After plant harvesting, roots (core and peel) and leaves were analyzed separately for carrot, while for lettuce, leaves and hearts were analyzed together. The corresponding bioconcentration factors (BCFs) were calculated. In carrots, a concentration gradient of 2,2′,3,4,4′,5′-hexabromodiphenyl ether (BDE-138) became evident that decreased from the root peel via root core to the leaves. For decabromodiphenyl ether (BDE-209) at the low concentration level (7 and 20 ng g⁻¹), the leaves incorporated the highest concentration of the target substance. For lettuce, a decrease in the BCF value (from 0.24 to 0.02) was observed the higher the octanol–water partition coefficient, except in the case of BDE-183 (BCF = 0.51) and BDE-209 (BCF values from 0.41 to 0.74). Significant influence of the soils and crop varieties on the uptake could not be supported. Metabolic debromination, hydroxylation or methylation of the target PBDEs in the soil–plant system was not observed.

In this study, a cost-effective and easily prepared adsorbent for fluoride removal was synthetized by loading activated aluminum and lanthanum onto hydrothermal palygorskite (HP) (denoted as La-Al-TAP). And the La-Al-TAP was characterized by scanning electron microscope (SEM), x-ray diffraction analysis (XRD), and x-ray photoelectron spectroscopy (XPS). As a result, the optimal condition for La-Al-TAP preparation was proposed as follows: 0.004 mol/L La(III) and 0.125 mol/L Al(OH)₃ colloid was loaded onto the acidulated HP (AP) with volume ratio of AP/La(III)/Al(OH)₃ = 1:6:1, and then La-Al-AP was calcined at 300 °C for 2 h. Results proved that the La-Al-HP adsorbent had a significantly larger surface (95.58 m²/g) than that of raw HP (34.31 m²/g). The amorphous structure provided a favorable site for fluoride adsorption, subsequently improving the adsorption capacity of HP. The results all indicated the formation of oxide La-Al-O composite at the surface of adsorbent. The adsorption of fluoride by adsorbent La-Al-TAP was well fitted to the Langmuir isotherm and the maximum adsorption capacity was up to 1.04 mg/g. It was also found that the adsorbent could be regenerated for such six times with good security performance. In conclusion, the newly prepared La-Al-TAP adsorbent in this study has potential as an excellent adsorbent for fluoride removal in groundwater remediation works.

The influence of manure and composts on the leaching of heavy metals from soil was evaluated in a model lysimeter experiment under controlled conditions. Soil samples were collected from experimental fields, from 0- to 90-cm layers retaining the layout of the soil profile layers, after the second crop rotation cycle with the following plant species: potatoes, spring barley, winter rapeseed, and winter wheat. During the field experiment, 20 t DM/ha of manure, municipal sewage sludge composted with straw (SSCS), composted sewage sludge (SSC), dried granular sewage sludge (DGSS), “Dano” compost made from non-segregated municipal waste (CMMW), and compost made from municipal green waste (CUGW) was applied, i.e., 10 t DM/ha per crop rotation cycle. The concentrations (μg/dm³) of heavy metals in the leachate were as follows: Cd (3.6–11.5) < Mn (4.8–15.4) < Cu (13.4–35.5) < Zn (27.5–48.0) < Cr (36.7–96.5) < Ni (24.4–165.8) < Pb (113.8–187.7). Soil fertilization with organic waste materials did not contaminate the percolating water with manganese or zinc, whereas the concentrations of the other metals increased to the levels characteristic of unsatisfactory water quality and poor water quality classes. The copper and nickel content of percolating water depended on the concentration of those metals introduced into the soil with organic waste materials. The concentrations of Cd in the leachate increased, whereas the concentrations of Cu and Ni decreased with increasing organic C content of organic fertilizers. The widening of the C/N ratio contributed to Mn leaching. The concentrations of Pb, Cr, and Mn in the percolating water were positively correlated with the organic C content of soil.

Water and sediment samples were collected from up to 17 sites in waterways entering the Corner Inlet Marine National Park monthly between November 2009 and April 2010, with the Chemcatcher passive sampler system deployed at these sites in November 2009 and March 2010. Trace metal concentrations were low, with none occurring at concentrations with the potential for adverse ecological effects. The agrochemical residues data showed the presence of a small number of pesticides at very low concentration (ng/L) in the surface waters of streams entering the Corner Inlet, and as widespread, but still limited contamination of sediments. Concentrations of pesticides detected were relatively low and several orders of magnitude below reported ecotoxicological effect and hazardous concentration values. The low levels of pesticides detected in this study indicate that agricultural industries were responsible agrochemical users. This research project is a rarity in aligning both agrochemical usage data obtained from chemical resellers in the target catchment with residue analysis of environmental samples. Based on frequency of detection and concentrations, prometryn is the priority chemical of concern for both the water and sediments studied, but this chemical was not listed in reseller data. Consequently, the risks may be greater than the field data would suggest, and priorities for monitoring different since some commonly used herbicides (such as glyphosate, phenoxy acid herbicides, and sulfonyl urea herbicides) were not screened. Therefore, researchers, academia, industry, and government need to identify ways to achieve a more coordinated land use approach for obtaining information on the use of chemicals in a catchment, their presence in waterways, and the longer term performance of chemicals, particularly where they are used multiple times in a year.

Sediment samples from a salt marsh habitat in the vicinity of Linden Chemical Plant (LCP) Superfund site in Brunswick Georgia, USA, were analyzed for the composition of total solvent extracts and sources of lipid compounds. Stable isotope analysis of carbon and nitrogen and gas chromatography-mass spectrometry analysis infer past multiple sources of organic matter (OM) from aquatic and terrestrial origin, e.g., phytoplankton, bacteria, and land plants, as well as anthropogenic contamination. The n-alkane and n-alkanol distributions in the sediment samples were dominated by long-chain homologues maximizing at C₂₅–C₂₇ for alkanes (carbon preference index (CPI) ∼1) and C₃₂ for n-alkanols indicating inputs from higher plants, but also microbial and petroleum-related sources. Fatty acid distribution was characterized by short-chain (< C₁₈) and branched homologues indicative of bacterial origin. The high abundance of dehydroabietic acid and anthropogenic contaminants, including alkylphenols, are indicative of the effects of past industrial activities in the LCP marsh area in Brunswick, Georgia.

Livestock manure and compost are commonly used to supply nutrients for crops and improve soil quality. However, excess application may increase the risk of nutrient loss and eutrophication. We investigated the potential leaching losses of nitrogen (N), phosphorus (P), and non-purgeable organic carbon (NPOC) over 105 days in the laboratory. Soils were amended with four treatments: (1) manure (BM) and (2) compost (BC) from cattle fed a typical finishing diet, (3) manure (DDGSM), and (4) compost (DDGSC) from cattle fed diets containing 60 % wheat dried distillers’ grains with solubles (DDGS) replacing barley grain. A non-amended control soil was included for comparison. Leachate samples were collected 0, 7, 21, 42, 70, and 105 days after amendment application. Amendment application significantly increased leaching loss of total nitrogen (TN), NO₃ ⁻-N, NH₄ ⁺-N, total phosphorus (TP), ortho-P (PO₄ ³⁻-P), and NPOC from soils by 2.2 to 154.8 times compared with the control. Regardless of whether DDGS was included in cattle diet, cumulative leaching losses of TN, NO₃ ⁻-N, TP, and PO₄ ³⁻-P were significantly higher, while NH₄ ⁺-N and NPOC were lower from compost-amended soil than manure-amended soil. The proportion of cumulative N leaching losses relative to the total N applied was greater with DDGSM and DDGSC than BM and BC, while a greater proportion of total P was leached from DDGSM and DDGSC than BM. Based on the results, more attention should be paid to the potential risk of soil nutrient leaching posed after applying manure and compost, and the higher risk of N and P leaching losses from soil amended with DDGS manure and compost than manure from beef cattle fed typical finishing diets.