Green algae of the genus Spirogyra: A potential absorbent for heavy metal from coal mine water

Algae have considerable capability for absorbing heavy metals from wastewaters and are considered an effective treatment technology. Heavy metal absorption from coal mine water from the Bhowra Abandoned mine (open cast mine) and the Sudamdih Shaft mine (underground mine waters), both located in Dhanbad, India, by cells of Spirogyra was studied at different dilutions (100 percent, 80 percent, 60 percent, 40 percent, and 20 percent). In the present study, the following 18 metals were selected for analysis: aluminium (Al), arsenic (As), silver (Ag), barium (Ba), beryllium (Be), bismuth (Bi), cadmium (Cd), cobalt (Co), chromium (Cr), cesium (Cs), copper (Cu), iron (Fe), gallium (Ga), indium (In), potassium (K), manganese (Mn), nickel (Ni), and vanadium (V). Accordingly, Al and K were found to be higher in concentration with respect to selected metals for both mine waters. The biosorption study revealed that higher amounts of Al, Bi, Co, Cs, Fe, Ga, Mn, Ni, and V were absorbed by algal biomass at 100 percent concentration from both mine waters. The maximum uptake of Cu, As, and Cd was measured at 60 percent, 40 percent, and 20 percent, respectively, for the Bhowra Abandoned mine water. The biosorption equilibrium study revealed that Ag, Al, Ba, Be, Bi, Co, Cr, Cs, Fe, Ga, In, K, Mn, Ni, and V were maximally absorbed by algal biomass at 100 percent concentration from Bhowra mine water, while the maximum uptake by the algal biomass measured for the Sudamidh coal mine water was for Al, As, Bi, Cu, Fe, and Mn at 100 percent concentration. The different physicochemical characteristics of mine water and drinking water standards was also studied. Accordingly, total dissolved solid and chemical oxygen demand concentrations exceeded the drinking water standards for water samples collected from both mines.     

Processing scheme based on selective dissolution to recycle food packaging and other polymeric wastes and its economic analysis

This investigation proposes the development of the selective dissolution process for recycling food packaging and other polymeric wastes. This process takes into account that the specific solvent of a particular polymer which is to be separated, must be a non-solvent for the remaining polymers. Likewise, taking into account the solubility of each polymer into various solvents as well as its production costs, the order of the polymers produced can be polyvinylchloride (PVC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polybutadiene (PB), polyacrylnitrile (PAN), polyesters (PES), nylon and polyurethanes (PU). However, cost analysis of the process revealed that the recycling of food packaging polymers in the order of PE, PVC, PP, and PS is more cost-effective.     

Polychlorinated biphenyls (PCBs) and halogenated flame retardants (HFRs) in multi-matrices from an electronic waste (e-waste) recycling site in Northern China

The present study investigated the occurrence of polychlorinated biphenyls (PCBs) and halogenated flame retardants (HFRs) in soil, water, reed, air and dust samples collected from the e-waste recycling region in Ziya Town, Northern China. The results showed that the concentrations of PCBs reached relative high level in environmental matrices in the study area. HFRs including polybrominated diphenyl ethers (PBDEs), dechlorane plus (DP), allyl 2,4,6-tribromophenyl ether (ATE), tetrabromoethylcyclohexane (TBECH), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), 2,3-dibromopropyl 2,4,6-tribromophenyl ether (DPTE), 1,2-bis-(2,4,6-tribromophenoxy) ethane (BTBPE) and so on were also widely detected in multi-matrices. Long-range atmospheric transport (LRAT) potentials of non-BDE HFRs were assessed to address the LRAR abilities of these compounds. Analysis of soil–air exchange of PCBs and HFRs showed that soil acted as a secondary source to the atmosphere only for a few low molecular weight compounds, while the direction of the flux of most detected chemicals was from air to soil.     

An investigation on the potential of metal recovery from the municipal waste incinerator in Taiwan

This study aimed to identify distribution of metals and to estimate the amount of these metals that can be potentially recovered from incineration residues. First, the partitioning behavior of Cr, Cu, Fe, Cd, Al, Zn, and Pb in bottom ash and fly ash was investigated in one large municipal waste incinerator in Taiwan. In addition, the material flow analysis (MFA) method was used to estimate the material flux of metals within incinerator plant, and to calculate the amount of metal recovery. According to the findings of this study, six metals (Fe, Al, Cu, Zn, Cr, and Pb) concentrated in bottom ash mostly, while Cd existed primarily in fly ash. The weight percentages of Fe (4.49%), Al (5.24%), Cu (1.29%), Zn (2.21%), and Pb (0.58%) in incinerator ash are high, and even higher than the compositions of natural minerals. Finally, the amount of Cr, Cu, Fe, Cd, Al, Zn and Pb that can be potentially recovered from incineration residues will reach 2.69 x 10(2), 1.46 x 10(4), 4.91 x 10(4), 6.92 x 10(1), 5.10 x 10(4), 1.85 x 10(4) and 4.66 x 10(3) ton/yr, respectively.     

Filter-based treatment of leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods

A pilot plant was set up to treat leachate from an industrial landfill containing shredder residues of end-of-life vehicles and white goods. The treatment plant consisted of aeration and sedimentation steps for pre-treatment, and a filter. The plant was designed to simultaneously remove various types of pollutants. The efficiencies of pre-treatment and of the main treatment step were investigated over a period of 3 years at the landfill site. By continuous aeration of the leachate the concentrations of Fe and Mn were reduced by 55% and 49%, respectively. By prolonged sedimentation suspended solid content was noticeably reduced (72%). In the filter, consisting of a mixture of peat and carbon-containing ash as a treatment medium, very high reduction of polar organic compounds, e.g. phenol (74%), o-and p-cresol (91%), and 2,4-dimethylphenol (73%), high average reduction of metals, e.g. Pb (78%), Fe (74%), Cu (73%), Mn (56%), Sn (55%), and Zn (47%), and good average reduction of DOC (26%), Tot-N (23%) and NH₄-N (46%) were achieved. Sixty non-polar compounds in the leachate, identified by GC–MS screening, occurred at trace level. Most of them were considerably reduced in the filter.     

Stockhome: A Spreadsheet Model of Urban Heavy Metal Metabolism

Computer models for analysis,visualising and decision support in environmentalresearch have become increasingly popular. TheStockhome project, where the urban metabolism ofheavy metals in Stockholm was studied, resultedin a database with historical data of the use ofgoods containing cadmium (Cd), chromium (Cr),copper (Cu), lead (Pb), mercury (Hg), nickel (Ni)and zinc (Zn). A spreadsheet model was developedto study flows and stocks of the metalconsumption process and emissions. The modelindicates uncertainties of the data, societalaspects such as field of use and rights ofdisposition of the goods. By considering goods asthe drivers of the emissions, the model would bewell suited for policy support.     

Environmental Sensitivity of a Tropical Coastline (Trinidad,West Indies) to Oil Spills

In the wider Caribbean region, Trinidad has been classified as a high risk area for oil spills by the Intergovernmental Marine Consultative Organization. In order to develop an oil spill environmental sensitivity index, the intertidal zones of fifteen representative coastal sites were monitored for physical and biological parameters during the dry and wet seasons. On a scale of 1–10, sheltered habitats with high productivity are the most sensitive to spilt oil with an index value of 10. Exposed habitats with low productivity are the least sensitive with a value of 1. The index applied to coastal habitats in Trinidad is as follows: mangrove swamps (10), coral-algal reefs (9), sheltered rocky coasts (8), sheltered tidal flats (7), mixed sand and gravel beaches (6), sheltered fine to medium-grained sand beaches (5), exposed rocky shores (4), exposed tidal flats (3), exposed medium to coarse-grained sand beaches (2) and eroding wavecut platforms (1). This study demonstrates an approach to effectively combine biological and physical parameters into a single environmental sensitivity index to oil spills.     

Count, identification and antimicrobial susceptibility of bacteria recovered from dental solid waste in Brazil

In Brazil, few studies on microbial content of dental solid waste and its antibiotic susceptibility are available. An effort has been made through this study to evaluate the hazardous status of dental solid waste, keeping in mind its possible role in cross-infection chain. Six samples of solid waste were collected at different times and seasons from three dental health services. The microbial content was evaluated in different culture media and atmospheric conditions, and the isolates were submitted to antibiotic susceptibility testing. A total of 766 bacterial strains were isolated and identified during the study period. Gram-positive cocci were the most frequent morphotype isolated (48.0%), followed by Gram-negative rods (46.2%), Gram-positive rods (5.0%), Gram-negative-cocci (0.4%), and Gram-positive coccobacillus (0.1%). Only two anaerobic bacteria were isolated (0.3%). The most frequently isolated species was Staphylococcus epidermidis (29.9%), followed by Stenotrophomonas maltophilia (8.2%), and Enterococcus faecalis (6.7%). High resistance rate to ampicillin was observed among Gram-negative rods (59.4%) and Gram-positive cocci (44.4%). For Gram-negative rods, high resistance was also noted to aztreonam (47.7%), cefotaxime (47.4%), ceftriaxone and cefazolin (43.7%), and ticarcillin-clavulanic acid (38.2%). Against Gram-positive cocci penicillin exhibit a higher resistance rate (45.0%), followed by ampicillin, erythromycin (27.2%), and tetracycline (22.0%). The present study demonstrated that several pathogenic bacteria are present in dental solid waste and can survive after 48 h from the waste generation time and harbor resistance profiles against several clinical recommended antibiotics.     

Treatment of urban stormwater for dissolved pollutants: A comparative study of natural organic filter media

Sorption capacities were evaluated for the dissolved stormwater (SW) pollutants onto two tree mulches and jute fiber. SW spiked with predetermined concentrations of copper (Cu), cadmium (Cd), hexavalent chromium (Cr ⁺⁶), lead (Pb), zinc (Zn), and benzo[a]pyrene (B[a]P), naphthalene (NP), fluoranthene (FA), 1,3‐dichlorobenzene (DCB), and butylbenzylphthalate (BBP) were used in this study. Each medium removed close to 100 percent of all the pollutants at the concentrations studied. Sorption capacities (μg/g) of the three organic media were in the order of jute > hardwood mulch > softwood mulch, and on a mole basis, both the heavy metals and the toxic organics were sorbed by the three media in an identical sequence: Cr ⁺⁶ > Cu, Zn > Cd > Pb; and NP > DCB > FA > B[a]P > BBP. Sorption capacities of the hardwood wood mulch and jute fiber for the pollutants were correlated with distinctive physical properties of the pollutants. © 2005 Wiley Periodicals, Inc.     

A comparative study on valuable products: bio-oil,biochar, non-condensable gases from pyrolysis of agricultural residues

Journal of Material Cycles and Waste Management - In this study, pyrolysis of agricultural residues, such as rice straw (RS), wheat straw (WS), and sugarcane bagasse (SB), was performed in a...     

Remediation Technologies Screening Matrix and Reference Guide: Version III

The U. S. Army Environmental Center (USAEC) is leading an effort to update the Remediation Technologies Screening Matrix and Reference Guide, Third Edition under the auspices of the Federal Remediation Technologies Roundtable (FRTR). Its purpose is to create a comprehensive “Remediation Technologies Yellow Pages” for use by those responsible for environmental cleanup. The Guide is being produced as a multiagency cooperative effort published under the FRTR. Members of this effort include USAEC, the U. S. Army Corps of Engineers (USACE), the Naval Facilities Engineering Service Center (NFESC), the Air Force Center for Environmental Excellence (AFCEE), the Environmental Protection Agency (EPA), the Department of Energy (DOE), the Department of the Interior (DOI), and the Interstate Technologies Regulation Cooperative (ITRC). This article provides a comprehensive look at environmental technology information provided in the electronic user-defined Remediation Technologies Screening Matrix and Reference Guide.     

H2O2/VisUV photo-oxidation process for treatment of waterborne hazardous substances—Reaction mechanism, rate model, and data for tubular flow and flow stirred tank reactors

This paper presents the chemical reaction engineering development of the H₂O₂/VisUV photo-oxidation process for treatment of hazardous waterborne substances, that occur in groundwater, leachates, and industrial wastewater. Reaction results, on benzene (BNZ), dichlorobenzene (DCB), trichloroethene (TCE), trichloroethane (TCA), and carbon tetrachloride (CTC), have been obtained, providing engineering data and models that can be used to size full-scale equipment. A photochemical flow stirred tank reactor (pcfSTR) and a photo-chemical tubular flow reactor (pcTFR) were used in the experimental work. Two experimental discoveries were made in the course of the work: (1) conventional thermal kinetics do not apply, the rate controlling variable is the photon flux, and (2) for the photo-chemical reactors used, the pcfSTR was more effective than the pcTFR. The following sub-topics are discussed: reaction mechanism, reactor hydrodynamics, photon flux effects, typical reaction data (on benzene and trichloroethane), and rate constants.     

Bioprocess technology for coal washery effluent treatment by Lemna minor

Duckweed species are promising macrophytes that can be used in wastewater treatment due to their rapid growth, ease of harvest, low fiber feed potential, and high protein contents. Waste‐water contaminants that are likely to be generated during washing of coal are total suspended solids (TSS), chemical oxygen demand (COD), acidity or alkalinity (pH), and metallic contaminants. Bioprocesses were developed to evaluate the potential of duckweed (Lemna minor) to treat coal washery effluent (CWE) as well as to study the impact on the biochemical changes of the Lemna minor. CWE samples were diluted with distilled water (DW) in different ratios as follows: T1‐CWE:DW(20:80%), T2‐CWE:DW(40:60%), T3‐CWE:DW(60:40%), T4‐CWE:DW (80:20%), T5‐CWE (100%), and Control‐DW(100%). The electrical conductivity of the effluent treated with Lemna minor was 0.035 deciSiemens per meter (dS/m) in the control at Day 10 and substantially higher at treatment ratios of 100, 80, and 60 percent (1.754, 1.842, and 1.631 dS/m). The highest amount of TSS was observed at test ratio T5 (38,834 mg/L), followed by T4 (28,816 mg/L), T3 (26,970 mg/L), T2 (15,320 mg/L), T1 (4,524 mg/L), and control (424 mg/L). Total hardness was higher (820 mg/L) in T4 compared to the control (220 mg/L). Total hardness of the effluent decreased after 30 days of incubation in all the treatment aliquots. The CWE at 20 percent concentration increased the duckweed population and no adverse impacts on its growth were observed. At higher concentration (T5) total mortality of Lemna minor was observed. The chlorophyll production was determined to be inversely proportional to the effluent concentration. Based on this study, it is concluded that Lemna minor can be used for treating CWE after dilution with fresh water.     

Vermistabilization and nutrient enhancement of anaerobic digestate through earthworm species Perionyx excavatus and Perionyx sansibaricus

The aim of the study was to examine safe reuse and recycling of organic waste digestate obtained from a biogas plant (5 % total solid) with enhanced nutrient value through vermitechnology. Two indigenous epigeic earthworm species Perionyx excavates and Perionyx sansibaricus were tried individually for this purpose. The results clearly show a significant increase in pH values from 6.5–7.4, electrical conductivity (21.3–21.7 %), total N (84.5–94.6 %), total P (35.9–47.1 %), total K (49.8–52.6 %), Ca (41.9–41.9 %) and a significant decrease in total organic C (17.1–22.4 %), C/N ratio (7.2–6.9), C/P ratio (20.3–20.6), COD (51.9–55.7 %), BOD (85.5–91.2 %). Similarly, indicator organisms (fecal coliforms and fecal streptococci) showed decrement at the end of the composting period (60 days). Fecal Coliforms reduce to nil, while in fecal streptococci a 6 log reduction was observed. Oxygen uptake rate dropped to 67.4–70 % for vermireactors. Overall, the aforementioned findings highlighted that the indigenous earthworm species could enhance the nutrient value of the anaerobic digestate, which could be utilized as an efficient soil conditioner.     

Influences of chemical activators on incinerator bottom ash

This research has applied different chemical activators to mechanically and thermally treated fine fraction (<14 mm) of incinerator bottom ash (IBA), in order to investigate the influences of chemical activators on this new pozzolanic material. IBA has been milled and thermally treated at 800 degrees C (TIBA). The TIBA produced was blended with Ca(OH)(2) and evaluated for setting time, reactivity and compressive strength after the addition of 0.0565 mole of Na(2)SO(4), K(2)SO(4), Na(2)CO(3), K(2)CO(3), NaOH, KOH and CaCl(2) into 100g of binder (TIBA+Ca(OH)(2)). The microstructures of activated IBA and hydrated samples have been characterized by X-ray diffraction (XRD) and thermogravimetry (TG) analysis. Thermal treatment is found to produce gehlenite (Ca(2)Al(2)SiO(7)), wollastonite (CaSiO(3)) and mayenite (Ca(12)Al(14)O(33)) phases. The thermally treated IBA samples are significantly more reactive than the milled IBA. The addition of Na(2)CO(3) can increase the compressive strength and calcium hydroxide consumption at 28-day curing ages. However, the addition of Na(2)SO(4), K(2)SO(4), K(2)CO(3), NaOH and KOH reduces the strength and hydration reaction. Moreover, these chemicals produce more porous samples due to increased generation of hydrogen gas. The addition of CaCl(2) has a negative effect on the hydration of TIBA samples. Calcium aluminium oxide carbonate sulphide hydrate (Ca(4)Al(2)O(6)(CO(3))(0.67)(SO(3))(0.33)(H(2)O)(11)) is the main hydration product in the samples with activated IBA, except for the sample containing CaCl(2).     

Decomposition of forest products buried in landfills

The objective of this study was to investigate the decomposition of selected wood and paper products in landfills. The decomposition of these products under anaerobic landfill conditions results in the generation of biogenic carbon dioxide and methane, while the un-decomposed portion represents a biogenic carbon sink. Information on the decomposition of these municipal waste components is used to estimate national methane emissions inventories, for attribution of carbon storage credits, and to assess the life-cycle greenhouse gas impacts of wood and paper products. Hardwood (HW), softwood (SW), plywood (PW), oriented strand board (OSB), particleboard (PB), medium-density fiberboard (MDF), newsprint (NP), corrugated container (CC) and copy paper (CP) were buried in landfills operated with leachate recirculation, and were excavated after approximately 1.5 and 2.5 yr. Samples were analyzed for cellulose (C), hemicellulose (H), lignin (L), volatile solids (VS), and organic carbon (OC). A holocellulose decomposition index (HOD) and carbon storage factor (CSF) were calculated to evaluate the extent of solids decomposition and carbon storage. Samples of OSB made from HW exhibited cellulose plus hemicellulose (C + H) loss of up to 38%, while loss for the other wood types was 0–10% in most samples. The C + H loss was up to 81%, 95% and 96% for NP, CP and CC, respectively. The CSFs for wood and paper samples ranged from 0.34 to 0.47 and 0.02 to 0.27 g OC g^?1 dry material, respectively. These results, in general, correlated well with an earlier laboratory-scale study, though NP and CC decomposition measured in this study were higher than previously reported.     

Pyrolysis of plastic packaging waste: A comparison of plastic residuals from material recovery facilities with simulated plastic waste

Pyrolysis may be an alternative for the reclamation of rejected streams of waste from sorting plants where packing and packaging plastic waste is separated and classified. These rejected streams consist of many different materials (e.g., polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), aluminum, tetra-brik, and film) for which an attempt at complete separation is not technically possible or economically viable, and they are typically sent to landfills or incinerators. For this study, a simulated plastic mixture and a real waste sample from a sorting plant were pyrolyzed using a non-stirred semi-batch reactor. Red mud, a byproduct of the aluminum industry, was used as a catalyst. Despite the fact that the samples had a similar volume of material, there were noteworthy differences in the pyrolysis yields. The real waste sample resulted, after pyrolysis, in higher gas and solid yields and consequently produced less liquid. There were also significant differences noted in the compositions of the compared pyrolysis products.     

Methane oxidation in water-spreading and compost biofilters.

This study evaluated two biofilter designs to mitigate methane emissions from landfill vents. Water-spreading biofilters were designed to use the capillarity of coarse sand overlain by a finer sand to increase the active depth for methane oxidation. Compost biofilters consisted of 238-L barrels containing a 1:1 mixture (by volume) of compost to expanded polystyrene pellets. Two replicates of each type of biofilter were tested at an outdoor facility. Gas inflow consisted of an approximately 1:1 mixture (by volume) of CH4 and CO2. Methane output rates (J(out); g m(-2) day(-1)) were measured using the static chamber technique and the Pedersen et al. (2001) diffusion model. Methane oxidation rate (J(ox); g m(-2) day(-1)) and fraction of methane oxidized (f(ox)) were determined by mass balance. For methane inflow rates (J(in)) between 250 and 500 g m(-2) day(-1), the compost biofilter J(ox), 242 g m(-2) day(-1), was not significantly different (P = 0.0647) than the water-spreading biofilter J(ox), 203 g m(-2) day(-1); and the compost f(ox), 69%, was not significantly different (P = 0.7354) than water-spreading f(ox), 63%. The water-spreading biofilter was shown to generally perform as well as the compost biofilter, and it may be easier to implement at a landfill and require less maintenance.     

Nutrients and heavy metals distribution in thermally treated pig manure.

Ash from pig manure treated by combustion and thermal gasification was characterized and compared in terms of nutrient, i.e., potassium (K), phosphorus (P) and heavy metal, i.e., cadmium (Cd), chromium (Cr), copper (Cu), nickel (Ni) and zinc (Zn) contents. Total nutrient and metal concentrations were measured using energy dispersive X-ray fluorescence analysis. Acid (HNO3, H2SO4) and water-extractable concentrations were also measured both in non-classified ash and in selected ash particle size fractions using flame atomic absorption spectrometry and colorimetric spectrometry. Results indicate that ash from gasified manure contained more water-extractable K in comparison with combusted manure whereas the opposite was the case with respect to P. Heavy metals Ni, Cr and Cd were present in higher concentrations in the fine particle size fractions (< 30 microm of particle diameter), whereas K, P, Zn and Cu exhibited higher concentrations in the coarser particle size fractions (> 30 microm).     

Cradle-to-Grave Life Cycle Assessment and Techno-Economic Analysis of Polylactic Acid Composites with Traditional and Bio-Based Fillers

This research focused on life cycle assessment (LCA) and techno-economic analysis (TEA) comparisons of polylactic acid (PLA) composites, in order to compare organic to inorganic fillers. Organic fillers included DDGS, flax, hemp, rice husks, and wood, and were compared against inorganic fillers (glass and talc) for PLA-based composites. This study utilized LCAI and TEA methodology to estimate and quantify costs, emissions, and energy intensity (EI) associated with material acquisition, processing, transport, and end-of-life treatment used during plastic composite production. Emission categories analyzed include global warming potential (GWP), air acidification (AA), air eutrophication (AE), water eutrophication (WE), ozone layer depletion (OLD), air smog (AS), high carcinogens (HC), and high non-carcinogens (HNC). To achieve a “Cradle-to-Grave” perspective, two models were meshed, the plastic comparator (PC) and EIO-LCA (EIO), to simulate the EI and emissions associated over the entire life cycle. Based assumptions used, this research has shown that utilizing land fill end-of-life treatment and glass filler composite was the most environmentally harmful option, and maintained the highest economic impact, for all impact categories during PLA composite production. Alternatively, both DDGS and wood filler composites paired with recycling end-of-life treatment were shown to be the least environmentally damaging method and incurred the lowest cost of all PLA composites considered. This study also suggests that utilization of organic bio-based fillers produces a lower economic/environmental impact, and EI, compared to utilization of inorganic fillers in PLA composites. Accordingly, this research has demonstrated the impact of LCA/TEA paired analysis when assessing the bioplastic and biocomposite processing, which may be utilized as a precursor for parallel research undertakings.