Two-stroke petrol engines find wide applications in the areas like chain saws, weed cutters, and power sprayers because of their compactness and higher power to weight ratio. In the present study, the feasibility of using vegetable-based lubricant instead of ordinary mineral 2 T oil is investigated. M15 (85% petrol + 15% methanol) and E15 (85% petrol + 15% ethanol) blend with gasoline are used as the fuel. Experiments were carried out in a two-stroke air-cooled engine equipped with a rope brake dynamometer. It is observed that the vegetable-based lubricant (sunflower oil) is miscible with the tested fuels. The frictional power for the vegetable-based lubricant was found to be less than that of mineral 2 T oil. The brake thermal efficiency improved and the brake-specific fuel consumption decreased for the sunflower oil-based lubricant. The combination of E15 + sunflower oil lubricant exhibited the greatest benefits, raising the brake thermal efficiency by 3.4% and reducing the brake-specific fuel consumption by 1.4%. Hydrocarbon and carbon monoxide emissions were lower for the vegetable-based lubricant than the 2 T mineral oil.

Locally available low-cost material viz. sand from the Kaliani river of Kanaighat area of Golaghat district Assam, India, was collected. The sand was fractionated and the different fractions were characterized by classical chemical analysis, powder XRD, SEM-EDXA, DTA-TGA, and by FT-IR. The chemical analysis of the size fraction of a 600–850-μm range gave more than 90% silica. This fractionated portion was modified by coating with iron oxide. Coating was carried out on the washed and separated sand by repeated treatment of Fe(NO₃)₃ at 110 and 600 °C, respectively. From FESEM analysis, formation of iron oxide coating over sand surface is clearly observed. The coated sand was used to remove toxic fluoride ion from the drinking water. Iron oxide-coated sand shows highly improved fluoride removal capacity compared to raw sand. The defluoridation capacity of coated sands rose up to 89% from 7% in uncoated raw sand. The effects of different parameters like adsorbent dose, contact time, temperature, initial fluoride concentration, and pH and the effects of different anions present in water along with arsenic on defluoridation capacity of the material were studied in a batch mode.

Oestrogen-like compounds with biological activities are commonly chemical additives, which have been added into chicken feed for years. Large amount of oestrogen and oestrogen-like compounds were also found in chicken faeces. We believe that such compounds are incorporated into agricultural products as faeces are used in food production process as fertilizer, and they will influence human health. Biodegradation is an environment-friendly, economical way to reduce environmental disruption by oestrogen. In order to degrade oestrogen, we chose 11 bacterial strains that could exhibit high degradation activity against steroid compounds. Oestradiol (E2) and ethynyloestradiol (an artificial oestradiol-like compound; EE2) in chicken faeces were degraded by the bacteria and were detected by high-performance liquid chromatography (HPLC). The results show that a mixture of oestrogen-degrading bacteria exhibited higher rate of degradation than each of the 11 bacteria did individually. Therefore, we cultured the mixture of 11 bacteria with chicken faeces. An oestrogen-like compound found in chicken feed and faeces could be also degraded by the bacteria.

Under low nitrogen (N) input into rain-fed peat bogs, Sphagnum moss efficiently filters incoming N, preventing invasion of vascular plants and peat oxygenation. Elevated atmospheric N deposition, in combination with climatic warming, may cause retreat of bryophytes and degradation of peat deposits. There are concerns that higher emissions of greenhouse gases, accompanying peat thinning, will accelerate global warming. Breakthrough of deposited N below living moss has been quantified for two Central European peat bogs dominated by Sphagnum magellanicum. In the 1990s, the northern site, ZL, received three times more atmospheric N (> 40 kg ha⁻¹ year⁻¹) than the southern site, BS. Today, atmospheric N inputs at both sites are comparable (15 and 11 kg ha⁻¹ year⁻¹, respectively). Replicated peat cores were collected from the wet central segments of both study sites, ¹⁵N-NO₃⁻ tracer was applied on the moss surface, and the peat cores were incubated under water-logged conditions. After 40 weeks, the rate of downcore leaching of the ¹⁵N tracer was assessed. The recent history of high N pollution at ZL did not accelerate ¹⁵N penetration into deeper peat layers, relative to BS. At both sites, less than 3% of the ¹⁵N tracer reached the shallow depth of 9 cm. Analysis of control peat cores, along with a ²¹⁰Pb chronology, revealed removal of the “excess” N from the ZL peat profiles prior to sampling. Following a decrease of atmospheric N pollution in the past two decades, efficient filtering of atmospheric N by Sphagnum at ZL has been renewed.

In the present study, biochar was prepared from scrap wetland macrophyte Arundo donax at different temperatures and then was evaluated for its feasibility as substrate to enhance nitrogen removal performance of surface flow constructed wetlands (SFCWs). Three groups of SFCW systems with different addition of biochar (0, 10, 20%, v/v) were constructed to investigate the effect of dissolved organic matter (DOM) released from biochar on nitrogen transformation. Results showed that the concentration of DOM released from biochar widely ranged from 6.01 to 125.67 mg L⁻¹, and the DOM amount decreased with increasing pyrolysis temperature. Five humic acid-like components of DOM were identified by the parallel factor analysis (PARAFAC) model. The release capacity of DOM from biochar is observed to be closely related to microbial nitrogen removal efficiency. Enhanced removal efficiencies of NO₃⁻-N (81.16%) and total nitrogen (85.62%) were achieved in SFCWs with 20% biochar, which was higher than SFCWs with 10% biochar (62.74 and 73.83%) and the control groups with no biochar (36.16 and 57.90%), respectively. Increased plant height in SFCWs with more biochar addition confirmed the positive effect of biochar on plant growth. Results from the present study suggested that the application of wetland plant-derived biochar was a promising strategy to enhance treatment performance and utilization of waste biomass resource in SFCWs.

The mining and processing of metal ores in the UK has left a legacy of environmental degradation, and abandoned metal mines still pose a significant threat to terrestrial and fluvial environments. Flow gauging, water quality and geophysics were combined in an integrated assessment of surface and subsurface hydrological contamination at Esgair Mwyn, an abandoned mine in Ceredigion, Wales. Heavy metals discharged from the site are polluting downstream watercourses, leading to widespread Environmental Quality Standards (EQS) compliance failures. Through salt water dilution gauging and water quality sampling, a daily efflux of 876 g of heavy metals was calculated, with contaminant mobilisation occurring mainly in two primary surface streams draining an exposed tailings heap. Electrical resistivity tomography subsurface imaging found a seepage plane within the tailings lagoon wall, whilst the main tailings heap became increasingly saturated with depth. A large adjacent field also had a high potential to convey pollutants in solution, yet its morphological characteristics have limited transmission, as the area acts as a passive treatment type system. With remediation of already polluted water both difficult and expensive, this approach provides a cost-effective way to identify the origins and pathways of contaminants, informing mitigation strategies focussed on containment. Esgair Mwyn is not an isolated case, as abandoned metal mines release at least 860 t of heavy metals annually into UK water bodies. These techniques could reduce or prevent abandoned metal mine hydrological pollution for decades to come, and enable associated UK water bodies to comply with future water quality standards.

The weathering release rate of base cations (BCw) from soil minerals is fundamentally important for terrestrial ecosystem growth, function, and sensitivity to acid deposition. Understanding BCw is necessary to reduce or prevent damage to acid-sensitive natural systems, in that this information is needed to both evaluate the effectiveness of existing policies, and guide establishment of further policies in the event they are required. Yet BCw is challenging to estimate. In this study, major sources of uncertainty associated with a process-based model (PROFILE) commonly used to estimate weathering rates were quantified in the context of efforts to quantify BCw for upland forest sites across the continental USA. These include uncertainty associated with parameterization of mineral content where horizon data are not available, stoichiometry of individual minerals, and specific surface area of soil and individual soil minerals. Mineral stoichiometry was not an important influence on BCw estimates (uncertainty < 1%). Characterizing B horizon mineralogy by averaging A and C horizons was found to be a minor (< 5%) contributor to uncertainty in some areas, but where mineralogy is known to vary with depth the uncertainty can be large. Estimating mineral-specific surface areas had a strong influence on estimated BCw, with rates increasing by as much as 250%. The greatest uncertainty in BCw estimates, however, was attributed to the particle size class-based method used to estimate the total specific surface area upon which weathering reactions can take place. The resulting uncertainty in BCw spanned multiple orders of magnitude at individual sites, highlighting this as the greatest challenge to ongoing efforts to produce robust BCw estimates across large spatial scales in the USA. Recommendations for improving estimates of BCw to support robust decision making for protection against terrestrial acidification are provided.

Biosorbents are the natural origin adsorbents, which popularity in environmental engineering is steadily increasing due to their low price, ease of acquisition, and lack of the toxic properties. Presented research aimed to analyze the possibility of chemical modification of the straw, which is a characteristic waste in the Polish agriculture, to improve its biosorption properties with respect to removal of selected metals from aquatic solutions. Biosorbents used during the tests was a barley straw that was shredded to a size in the range of 0.2–1.0 mm. The biosorption process was performed for aqueous solutions of zinc at a pH 5. Two different modifications of straw were analyzed: esterification with methanol and modification using the citric acid at elevated temperature. The results, obtained during the research, show a clear improvement in sorption capacity of the straw modified by the citric acid. In the case of straw modified with methanol, it has been shown that the effectiveness of zinc biosorption process was even a twice lower with respect to the unmodified straw. Moreover, it was concluded that the removal of analyzed metals was based mainly on the ion-exchange adsorption mechanism by releasing a calcium and magnesium ions from the straw surface to the solution. Graphical Abstract ᅟ

Lead is one of the most potentially toxic metals present in soils. In situ Pb immobilization techniques reducing its bioavailability to soil organisms are of increasing interest. The present work compares the effectiveness of nanoscale zero-valent iron (nZVI), compost, and phosphate for Pb immobilization in an acidic, artificially polluted soil after different contact times (15 and 45 days). The availability and mobility of Pb were evaluated by the Tessier extraction procedure and the toxicity characteristics leaching procedure (TCLP). The impact on soil properties and soil phytotoxicity was also evaluated. The phosphate was the most effective treatment in all sampling times, reaching Pb reductions in more available fractions of 72%, followed by compost (40%) and nZVI (32%). Comparing the two sampling times, a significant reduction of available Pb in phosphate-treated soils was observed at a longer contact time. Soil properties changed depending on the treatment. In general, the application of compost improved the soil fertility, soils treated with nZVI showed an increase of pH and available sodium and iron concentration, and the treatment with phosphate increased available phosphorus concentration in soil, but was less than that obtained by the compost treatment. Regarding the soil phytotoxicity, Vicia sativa showed moderate phytotoxicity to untreated Pb-polluted soils, and the different treatments decreased it. In conclusion, at the experimental conditions, the use of phosphate resulted as more effective than compost and nZVI for reducing Pb availability in an acidic soil. Longer-term assays are necessary to evaluate the stability of the process.

Minimizing the risks associated with manure-borne pathogenic microorganisms requires an understanding of microbial survival under realistic field conditions. The objective of this 3-year study was to assess the fate of Salmonella (SALM) and fecal indicator bacteria (FIB), E. coli (EC) and enterococci (ENT), in glacial till-derived soils, after application of poultry manure (PM) to cornfields under chisel-plowed (CP) or no-till (NT) management. From 2010 to 2012, soil samples were obtained each spring at 0–15- and 15–30-cm depths, to determine whether over-wintering of target bacteria had occurred. Sampling was followed by application of PM at low (PM1) and high (PM2) rates, based on nitrogen application goals. In 2012, soil samples were collected 21, 42, and 158 days after manure application (DAM), to assess the effects of time, application rates, and tillage on frequency of detection and concentrations of target bacteria. Despite dry conditions, all three target organisms were detected 158 DAM in 2012, and detection of these organisms in spring soil samples from manured plots in 2011 and 2012, nearly a full year after PM application, suggests that these organisms can persist in the soil environment long after application. The highest SALM concentration (790 cfu/g dry weight) and detection rate (25%) was found in PM2 plots 42 DAM. SALM were detected more frequently in CP plots (20%) compared to NT plots (5%). In contrast, tillage practices had no apparent effect on EC or ENT survival, as indicated by both soil, and decay rates estimated from tile-water bacteria concentrations. Decay rate constants (μ) ranged from 0.044 to 0.065 day⁻¹ for EC and 0.010 to 0.054 day⁻¹ for ENT.