Aqueous film-forming foam, used in firefighting, and biowastes, including biosolids, animal and poultry manures, and composts, provide a major source of poly- and perfluoroalkyl substances (PFAS) input to soil. Large amounts of biowastes are added to soil as a source of nutrients and carbon. They also are added as soil amendments to improve soil health and crop productivity. Plant uptake of PFAS through soil application of biowastes is a pathway for animal and human exposure to PFAS. The complexity of PFAS mixtures, and their chemical and thermal stability, make remediation of PFAS in both solid and aqueous matrices challenging. Remediation of PFAS in biowastes, as well as soils treated with these biowastes, can be achieved through preventing and decreasing the concentration of PFAS in biowaste sources (i.e., prevention through source control), mobilization of PFAS in contaminated soil and subsequent removal through leaching (i.e., soil washing) and plant uptake (i.e., phytoremediation), sorption of PFAS, thereby decreasing their mobility and bioavailability (i.e., immobilization), and complete removal through thermal and chemical oxidation (i.e., destruction). In this review, the distribution, bioavailability, and remediation of PFAS in soil receiving solid biowastes, which include biosolids, composts, and manure, are presented.

Heteroatom doped nanomaterials are reported to be excellent electrodes for energy storage and conversion applications. However, the introduction of these heteroatoms in materials such as carbon nitride is quite challenging owing to the poor thermodynamic stability of these atoms in the carbon matrix. In this report, we demonstrate the single-step approach for the preparation of highly ordered nanoporous carbon oxynitride (O-MCN) materials with tailored pore sizes by employing carbohydrazide as a single C, N, O precursor using nano-templating approach. Experimental characterization of the O-MCN confirms oxygen doping in C-N framework. Density functional theory (DFT) calculations demonstrate that the O-MCN optimized with AB type bilayer structure can adsorb nine Li ions per unit cell with mild Li-ion binding energy value of 5.16 eV. The synthesized O-MCN materials are firstly applied in Li-ion batteries as anode materials. The optimized O-MCN displays 2.5 times higher reversible capacity than that of non-porous g-C3N4 with remarkable stability in the long run in the Li-ion battery.

Valorisation of food waste offers an economical and environmental opportunity, which can reduce the problems of its conventional disposal. Food waste is commonly disposed of in landfills or incinerated, causing many environmental, social, and economic issues. Large amounts of food waste are produced in the food supply chain of agriculture: production, post-harvest, distribution (transport), processing, and consumption. Food waste can be valorised into a range of products, including biofertilisers, bioplastics, biofuels, chemicals, and nutraceuticals. Conversion of food waste into these products can reduce the demand of fossil-derived products, which have historically contributed to large amounts of pollution. The variety of food chain suppliers offers a wide range of feedstocks that can be physically, chemically, or biologically altered to form an array of biofertilisers and soil amendments. Composting and anaerobic digestion are the main large-scale conversion methods used today to valorise food waste products to biofertilisers and soil amendments. However, emerging conversion methods such as dehydration, biochar production, and chemical hydrolysis have promising characteristics, which can be utilised in agriculture as well as for soil remediation. Valorising food waste into biofertilisers and soil amendments has great potential to combat land degradation in agricultural areas. Biofertilisers are rich in nutrients that can reduce the dependability of using conventional mineral fertilisers. Food waste products, unlike mineral fertilisers, can also be used as soil amendments to improve productivity. These characteristics of food wastes assist in the remediation of contaminated soils. This paper reviews the volume of food waste within the food chain and types of food waste feedstocks that can be valorised into various products, including the conversion methods. Unintended consequences of the utilisation of food waste as biofertilisers and soil-amendment products resulting from their relatively low concentrations of trace element nutrients and presence of potentially toxic elements are also evaluated.

Chromium from tannery waste dump site causes significant environmental pollution affecting surrounding flora and fauna. The primary aims of this study were to survey vegetation, investigate the degree of soil pollution occurring near tannery waste dump site and make a systematic evaluation of soil contamination based on the chromium levels found in plants and earthworms from the impacted areas. This paper presents the pollution load of toxic heavy metals, and especially chromium, in 10 soil samples and 12 species of plants. Soil samples were analysed for heavy metals by using ICP-MS/ICP-OES method. Results indicated that Cr in soils exceeded soil quality guideline limits (SQGL). The total chromium present in the above ground parts of plants ranged from 1.7¿mg¿kg-1 in Casuarina sp.¿to 1007¿mg¿kg-1 in Sonchus asper. The Cr bioaccumulation in Eisenia fetida from tannery waste soil ranged from 5 to 194¿mg¿kg-1. The high enrichment factor of Cr in S. asper and bioaccumulation factor in earthworms indicate that there is a steady increase of toxic chromium risk in this area, which could be correlated with the past dumping activity. Emphasis needs to be put on control measures of pollution and remediation techniques in such areas to achieve an ecologically sustainable industrialisation.

Heavier fraction hydrocarbons (C15-C36) formed in soil after biotic and abiotic weatherings of engine oil are the continuing constraints in the bioremediation strategy, and their bioavailability remains a poorly quantified regulatory factor. In a microcosm study, we used two strains of Pseudomonas, P. putida TPHK-1 and P. aeruginosa TPHK-4, in strategies of bioremediation, viz., natural attenuation, biostimulation and bioaugmentation, for removal of weathered total petroleum hydrocarbons (TPHs) in soil contaminated long-term with high concentrations of engine oil (39,000¿41,000 mg TPHs kg-1 soil). Both the bacterial strains exhibited a great potential in remediating weathered hydrocarbons of engine oil. Addition of inorganic fertilizers (NPK), at recommended levels for bioremediation, resulted in significant inhibition in biostimulation/enhanced natural attenuation as well as bioaugmentation. The data on dehydrogenase activity clearly confirmed those of bioremediation strategies used, indicating that this enzyme assay could serve as an indicator of bioremediation potential of oil-contaminated soil. Extraction of TPHs from engine oil-contaminated soil with hydroxypropyl-ß-cyclodextrin (HPCD), but not 1-butanol, was found reliable in predicting the bioavailability of weathered hydrocarbons. Also, 454 pyrosequencing data were in accordance with those of bioremediation strategies used in the present microcosm study, suggesting the possible use of pyrosequencing in designing approaches for bioremediation.

Diesel is an important petroleum product, and a common pollutant in soil caused by leaks and accidental spills. Studies dealing with the ecotoxicity of diesel towards earthworms always relied on growth inhibition endpoint (EC50) values that were determined based on the spiked concentrations (nominal), ignoring the substantial portion of hydrocarbons volatilized from soil. In the present study we used, for the first time, the measured concentrations of total petroleum hydrocarbons (TPHs) from soil-applied diesel to assess earthworm (Eisenia fetida) survival, and the activities of dehydrogenase, urease and nitrification as indicators of soil health. The mortality endpoint (LC50) value for initially measured concentrations after exposure of earthworms to diesel for 28¿days was 916¿±¿10¿mg TPHs kg-1 soil which was equivalent to the nominal (initially added) concentration of 1426¿±¿19¿mg TPHs kg-1 soil. Morphological abnormalities such as clitella swelling and curling were noticed when the measured concentrations of diesel were more than 971¿mg¿kg-1 soil. Significant increases in activities of soil dehydrogenase (38¿58%) as well as urease were observed in the diesel-applied soil. Presence of earthworms further enhanced the activities of these soil enzymes. Nitrification was sensitive to application of diesel to soil, and it was inhibited in a dose-related manner even in the presence of earthworms. The differential response of the toxicity criteria to diesel-contaminated soil observed in the present study clearly warrants more studies involving several soil health parameters to arrive at a generalization of ecotoxicity of an environmental pollutant.

© 2016 American Institute of Chemical Engineers Soils contaminated with crude oil are rich sources of enzymes suitable for both degradation of hydrocarbons through bioremediation processes and improvement of crude oil during its refining steps. Due to the long term selection, crude oil fields are unique environments for the identificati on of microorganisms with the ability to produce these enzymes. In this metagenomic study, based on Hiseq Illumina sequencing of samples obtained from a crude oil field and analysis of data on MG-RAST, Actinomycetales (9.8%) were found to be the dominant microorganisms, followed by Rhizobiales (3.3%). Furthermore, several functional genes were found in this study, mostly belong to Actinobacteria (12.35%), which have a role in the metabolism of aliphatic and aromatic hydrocarbons (2.51%), desulfurization (0.03%), element shortage (5.6%), and resistance to heavy metals (1.1%). This information will be useful for assisting in the application of microorganisms in the removal of hydrocarbon contamination and/or for improving the quality of crude oil. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:638¿648, 2016.

We exposed the microalgal strain, Chlorella sp. MM3, to unused or used engine oil, or their water accommodated fractions (WAFs) to determine growth inhibition and response of antioxidant enzymes. Oil type and oil concentration greatly affected the microalgal growth. Used oil at 0.04¿% (0.4¿g L-1) resulted in 50¿% inhibition in algal growth, measured in terms of chlorophyll-a, while the corresponding concentration of unused oil was nontoxic. Similarly, used oil WAF showed significant toxicity to the algal growth at 10¿% level, whereas WAF from unused oil was nontoxic even at 100¿% concentration. Peroxidase enzyme in the microalga significantly increased with used oil at concentrations above 0.04¿g L-1 whereas the induction of superoxide dismutase and catalase was apparent only at 0.06¿g L-1. Activities of the antioxidant enzymes increased significantly when the microalga was exposed to 75 and 100¿% WAF obtained from used oil. The used oil toxicity on microalga could be due to the presence of toxic soluble mono- and polyaromatic compounds, heavy metals, and other compounds attained by the oil during its use in the motor engines.

Four bacterial strains, capable of degrading diesel oil, n-alkanes or hexadecane, were isolated from soils contaminated with petroleum oil and identified. Strains of Pseudomonas sp., Pseudomonas putida TPHK-1 and Pseudomonas aeruginosa TPHK-4, were more efficient in degrading high concentrations of the hydrocarbons than the other two strains, Stenotrophomonas maltophilia TPHK-2 and Acenitobacter sp. TPHK-3. P. putida TPHK-1 exhibited tolerance to very high concentrations of heavy metals such as cadmium, lead, zinc and copper. The innate ability of P. putida TPHK-1, as evidenced by the amplified genes alkB1 and alkB2 that encode alkane hydroxylases, and cat12o and cat23o coding for catechol dioxygenase, in degrading diesel oil in the presence of heavy metals is far greater than that of the strains reported in the literature. Heavy metal tolerance coupled with rapid degradation of hydrocarbons, even at high concentrations, suggests that P. putida TPHK-1 has a great potential in remediating soils contaminated with mixtures of hydrocarbons and heavy metals.

A study was conducted in the Department of Environmental Sciences, Tamil Nadu Agricultural University, Coimbatore, India, to transform the normal compost into bioactive compost, which has multiple benefits to the crop system. The key players in this transformation process were Azotobacter sp., Pseudomonas sp., Phosphobacteria sp. and the waste materials like poultry litter and spent wash. This enrichment process increases both the quality and nutrient content of the municipal solid waste compost significantly. A study was carried out to evaluate the effect of application of different levels of enriched municipal solid waste compost on the availability of the macronutrient content to the rice field soil. The effect of enriched compost on soil available nutrients was significant. The soil ammonium nitrogen and soil nitrate nitrogen content was found to be high in the plots where the enriched compost was applied along with inorganic fertilizer with the values of 38.87 mg kg-1 and 32.87 mg kg-1, respectively. In addition, the availability decreased towards crop growth. The soil available P and K were also increased with enriched compost application to about 22.46 kg ha-1 and 647 kg ha-1 compared with control values of 19.44 kg ha-1 and 518 kg ha-1, respectively. Both phosphorus and potassium content decreased towards advancement of crop growth. © 2007 Taylor & Francis.

A field experiment was conducted at Tamil Nadu Agricultural University, Coimbatore, India, to study the effect of Enriched Municipal Solid Waste Compost (EMSWC) application on growth, plant nutrient uptake and yield of rice in RBD during the year of 2004. The growth attributes viz., plant height, leaf area index, number of tillers and dry matter production differed significantly due to different treatments. These attributes increased significantly owing to the application of enriched compost, which has enhanced nutrient level, which leads to the continuous availability of nutrients in available form to the plants. The highest grain yield and straw yield were observed in the treatment combination of 25% of enriched compost and 75% of recommended dose of inorganic fertilizer (T5) with value of 5.22 and 8.65 t ha-1, respectively. Application of 5 t ha-1 enriched MSWC in combination with 25% N through inorganic fertilizer recorded grain yield of 4.33 t ha-1. The lowest grain yield (3.78 t ha-1) was recorded in treatment where the compost was applied alone. © 2007 Asian Network for Scientific Information.

A study was conducted in the Department of Environmental Science, Tamil Nadu Agricultural University, Coimbatore, to transform the normal compost into bioactive compost through the addition of various substrates, which has multiple benefits to the crop system. The key players in this transformation process were Azotobacter, Pseudomonas, Phosphobacteria, composted poultry litter, rock phosphate and diluted spent wash. This enrichment process has increased the nutritive value of compost. The highest nitrogen content (1.75%) and phosphorus content (1.16%) was observed in the treatment T5 (compost enriched with composted poultry litter, spent wash, microbial inoculants and rock phosphate). The beneficial microorganism viz., Azotobacter, Pseudomonas and Phosphobacteria population were higher in the treatment T5 where all the inputs (composted poultry litter, microbial consortium, rock phosphate and spent wash) were added to the compost. The plant growth promoters viz., IAA and GA content was more in the treatment applied with spent wash and microbial inoculum. Beneficial microorganisms, composted poultry litter, rock phosphate and diluted spent wash contributes maximum level of nutrients and growth promoters to the compost with small expenses. © 2007 Asian Network for Scientific Information.