Global perspective of municipal solid waste and landfill leachate: generation, composition, eco-toxicity, and sustainable management strategies

Globally, more than 2 billion tonnes of municipal solid waste (MSW) are generated each year, with that amount anticipated to reach around 3.5 billion tonnes by 2050. On a worldwide scale, food and green waste contribute the major proportion of MSW, which accounts for 44% of global waste, followed by recycling waste (38%), which includes plastic, glass, cardboard, and paper, and 18% of other materials. Population growth, urbanization, and industrial expansion are the principal drivers of the ever-increasing production of MSW across the world. Among the different practices employed for the management of waste, landfill disposal has been the most popular and easiest method across the world. Waste management practices differ significantly depending on the income level. In high-income nations, only 2% of waste is dumped, whereas in low-income nations, approximately 93% of waste is burned or dumped. However, the unscientific disposal of waste in landfills causes the generation of gases, heat, and leachate and results in a variety of ecotoxicological problems, including global warming, water pollution, fire hazards, and health effects that are hazardous to both the environment and public health. Therefore, sustainable management of MSW and landfill leachate is critical, necessitating the use of more advanced techniques to lessen waste production and maximize recycling to assure environmental sustainability. The present review provides an updated overview of the global perspective of municipal waste generation, composition, landfill heat and leachate formation, and ecotoxicological effects, and also discusses integrated-waste management approaches for the sustainable management of municipal waste and landfill leachate.

Sewage treatment plant dust: An emerging concern for heavy metals-induced health risks in urban area

Metal-related pollution from dust is a significant source of toxic elements in urban areas. The present study aimed to assess the health risk posed by heavy metals present in dust samples to the people residing near the Sewage Treatment Plant (STP). Dust samples were collected from an STP with a capacity of 130 mega litres per day (MLD). Data analysis indicated highly contaminated STP dust with Enrichment Factor (EF) suggesting an anthropogenic origin of selected metals (As, Co, Al, Cu, Cr, Cd, Ba, Pb, Ni, Mn). The contamination factor values of metals highlighted a greater degree of contamination in the selected area. Notably, a strong correlation (>0.5) was observed between metals. The EF value was found to be >40 indicating high enrichment for all the metals except Fe. In-depth chemical analysis and health risk assessments were conducted, revealing an Excess Lifetime Cancer Risk (ELCR) value of 1 × 10-6 and HQ (Hazard Quotient) value of 1. These values are significantly exceeding the safe limits for both children and adults which could develop cancerous properties in human beings. In an effort to reduce toxicity, dust samples were also subjected to vermicomposting treatment to assess the potential effectiveness of the earthworms. The EF value of vermicomposted dust came out to be lower than the untreated one. The Hazard Quotient (HQ) values for adults exhibited the following pattern of HQing > HQder > HQinh (indicating that the Hazard Quotient from ingestion is greater than that from dermal contact, which is in turn greater than inhalation). This investigation offers crucial insights into the increased risks of cancerous and non-cancerous ailments for individuals living or working in proximity to STPs. This research also highlights the pressing need to implement effective measures for safeguarding public health and mitigating environmental pollution in urban areas.

Effect of plastic mulch residue on plant growth performance and soil properties

Plastic mulch is widely utilized for weed control, temperature regulation, soil erosion prevention, disease management, and soil structure improvement, ultimately enhancing crop quality and yield. However, a significant issue with conventional plastic mulches is their low recycling rates, which can cause plastic residue to build up, thereby damaging soil quality and reducing crop yield. The emergence of biodegradable films offers a promising solution to mitigate this issue and reduce soil pollution. However, its potential effects on soil properties and plant performance remain unclear. In this study, low-density polyethylene (LDPE) and poly (butylene succinate-co-butylene adipate) (PBSA) were used to observe the effect of plastic mulch residues on soil properties and plant growth performance via potting experiment. Additionally, the interaction effects of compost and biochar as soil amendments with plastic mulch residues were also evaluated. The result of this study revealed that the type of plastic significantly affected the total nitrogen and magnesium uptake; however, the morphological traits of the tested plant (Japanese mustard spinach) were not significantly affected. The addition of compost and biochar led to a significant increase in both shoot and total dry weight of the plant, indicating a positive effect on its growth. The results of the two-way ANOVA indicated a significant influence of plastic type on dissolved phosphate (PO43-) levels and soil dehydrogenase activity (DHA). The interaction effect (plastic type with soil amendment) was statistically significant only for soil DHA. Neither plastic mulch residues nor soil amendments significantly affected other soil chemical properties. However, long-term experiments to systematically investigate the long-term effects of plastic residues are necessary.

Synthesis and antibacterial activity of nanoenhanced conjugate of Ag-doped ZnO nanorods with graphene oxide

In this paper, we report a successful synthesis of ZnO nanorods using the microwave-assisted technique, solid-state reaction method was utilized for the preparation of Zn_1-xAg_xO (x = 0.05, 0.1), Hummer's modified method for graphene oxide (GO) along with the sonication method to prepare GO-based Ag-doped ZnO (Zn_1-xAg_xO/GO: x  = 0.05, 0.1) nanocomposites. These nanorods and nanocomposites were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR), high-resolution transmission electron microscopy (HRTEM), and Raman spectroscopy for structural properties, scanning electron microscopy (SEM) along with energy dispersive X-ray (EDX) spectroscopy for morphological analysis, and UV-Vis spectroscopy for optical properties. XRD, FTIR, and Raman measurements substantiated that each sample is well crystallized in the single-phase polycrystalline wurtzite hexagonal structure of ZnO. The average crystallite size is found to be in decreasing order ranges 40 nm to 29 nm, respectively, along with a significant reduction in the optical bandgap. The SEM images showed a clear evidence of nanorods of ZnO, while the EDX spectra verified the presence of Zn, Ag, O, and C elements in the synthesized samples with their nominal percentage. Furthermore, the prepared nanocomposites effectively inhibited the growth ofStaphylococcus aureus and Escherichia coli. In comparison to pure ZnO nanorods, GO-based Ag-doped ZnO nanorods showed improved antibacterial activity against both S. aureus and E. coli.

Ecological adaptation of earthworms for coping with plant polyphenols, heavy metals, and microplastics in the soil: A review

In recent years, soil pollution by massive accumulation of heavy metals (HMs), microplastics, and refractory hydrocarbon chemicals has become an emerging and global concern, drawing worldwide attention. These pollutants influence soil diversity by hindering the reproduction, abundance, thereby affecting aboveground productivity. The scientific community has recently emphasized the contribution of earthworms to heavy metal accumulation, microplastic degradation, and the decomposition of organic matter in the soil, which helps maintain the soil structure. This review paper aimed to compile scientific facts on how earthworms cope with the effect of HMs, microplastics, and plant polyphenols so that vermiremediation could be widely applied for well-being of the soil ecosystem by environmentalists. Earthworms have special surface-active metabolites in their guts called drilodefensins that help them defend themselves against the oxidative action of plant polyphenols. They also combat the effects of toxic microplastics, and other oxidative compounds by elevating the antioxidant activities of their enzymes and converting them into harmless compounds or useful nutrients. Moreover, earthworms also act as biofilters, bioindicators, bioaccumulators, and transformers of oxidative polyphenols, microplastics, toxic HMs, and other pollutant hydrocarbons. Microorganisms (fungi and bacteria) in earthworms' gut of also assist in the fixation, accumulation, and transformation of these toxicants to prevent their effects. As a potential organism for application in ecotoxicology, it is recommended to propagate earthworms in agricultural fields; isolate, and culture enormously in industry, and inoculate earthworms in the polluted soil, thereby abate toxicity and minimizing the health effect caused by these pollutants as well enhance the productivity of crops.

Microbial strategies for degradation of microplastics generated from COVID-19 healthcare waste

COVID-19 pandemic has led to the generation of massive plastic wastes, comprising of onetime useable gloves, masks, tissues, and other personal protective equipment (PPE). Recommendations for the employ of single-use disposable masks made up of various polymeric materials like polyethylene, polyurethane, polyacrylonitrile, and polypropylene, polystyrene, can have significant aftermath on environmental, human as well as animal health. Improper disposal and handling of healthcare wastes and lack of proper management practices are creating serious health hazards and an extra challenge for the local authorities designated for management of solid waste. Most of the COVID-19 medical wastes generated are now being treated by incineration which generates microplastic particles (MPs), dioxin, furans, and various toxic metals, such as cadmium and lead. Moreover, natural degradation and mechanical abrasion of these wastes can lead to the generation of MPs which cause a serious health risk to living beings. It is a major threat to aquatic lives and gets into foods subsequently jeopardizing global food safety. Moreover, the presence of plastic is also considered a threat owing to the increased carbon emission and poses a profound danger to the global food chain. Degradation of MPs by axenic and mixed culture microorganisms, such as bacteria, fungi, microalgae etc. can be considered an eco-sustainable technique for the mitigation of the microplastic menace. This review primarily deals with the increase in microplastic pollution due to increased use of PPE along with different disinfection methods using chemicals, steam, microwave, autoclave, and incineration which are presently being employed for the treatment of COVID-19 pandemic-related wastes. The biological treatment of the MPs by diverse groups of fungi and bacteria can be an alternative option for the mitigation of microplastic wastes generated from COVID-19 healthcare waste.

Effect of Organic Manures on Growth, Yield, Leaf Nutrient Uptake and Soil Properties of Kiwifruit (Actinidia deliciosa Chev.) cv. Allison

In recent decades, organic kiwifruit farming has come up as a feasible method for high-quality kiwi production without using chemical fertilizers. The primary objective of this research was to investigate how the sole application of organic and the combined application of organic manures affected the growth, yields, and quality of Allison kiwifruit, as well as the soil's physicochemical characteristics. The field trial was conducted on cv. Allison to determine the efficacy of organic manures (OM) on growth, nutrient absorption, production and soil health. The experiment involved eight treatments, viz.: T₁: 100% Dairy manure (DM); T₂: 100% Vermicompost (VC); T₃: 100% chicken manure (CM); T₄: 50% DM + 50% CM; T₅: 50% DM + 50% VC; T₆: 50% CM + 50% VC; T₇: DM + CM + VC in equal proportions; and T₈: Recommended nutrients inorganic NPK + 40 kg DM. A randomized complete block design comprising three replicas was used in this investigation. The use of inorganic fertilizers (NPK) in combination with DM enhanced Spad Values Chlorophyll, fruit production, leaf number, leaf area, and stem diameter while also improving the soil's chemical characteristics. The flower initiation was recorded with DM and Vermicompost (50:50). Furthermore, when compared to inorganic fertilizer treatment, OM treatment significantly improved fruit quality by improving fruit chemical composition in terms of soluble solids contents and leaf nutrient status, as well as improving soil's physical properties with DM and Vermicompost (50:50). The study's outcome revealed that OM had a significant impact on flowering time, fruit SSC, leaf nutritional status, and soil physical characteristics. In comparison to organic treatments, recommended fertilizer dosages (NPK + DM) improved plant growth, fruit yield, and soil chemical characteristics.

Sodium hydroxide pre-treated Aspergillus flavus biomass for the removal of reactive black 5 and its toxicity evaluation

The present study was focused on the removal of Reactive Black 5 (RB5) from aqueous solution using pre treated Aspergillus flavus as a biosorbent. Pre-treatment of fungal biomass with 0.1 M sodium hydroxide facilitated the removal of dye effectively when compared to untreated fungal biomass. Optimum biosorption conditions for RB5 removal was determined as a function of dye concentration (50-400 mg/L), biosorbent concentration (100-500 mg/L), incubation time (1-7hrs), pH (3-8) and temperature (20-50 °C). At the optimum conditions, the maximum removal efficiency of RB5 achieved by NaOH pretreated A. flavus was 91%. The dye removal was studied kinetically and it obeys the pseudo-second order model and the experimental equilibrium data well fitted the Langmuir isotherm indicating monolayer adsorption of dye molecules on the biosorbent. The thermodynamic parameters such as a change in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were calculated and negative values of ΔG suggested that the dye removal process was spontaneous at all temperatures. Furthermore, the values of ΔH revealed that the adsorption process was endothermic. Recovery of RB5 from the fungal biomass was effective using 0.1 M Na₂CO₃ as an eluent. The interaction of adsorbate with biosorbent was analyzed using UV-Vis and FT-IR spectroscopy, SEM and XRD analyses. Phytotoxicity and microbial toxicity studies revealed the non-toxic nature of the treated dye solution. Hence, the fungal biomass pretreated with NaOH was efficient in decolorizing RB5 as well as composite raw industrial effluent generated from dyeing industries.

Vermiremediation of allopathic pharmaceutical industry sludge amended with cattle dung employing Eisenia fetida

The present study aims to vermiremediate allopathic pharmaceutical industry sludge (AS) amended with cattle dung (CD), in different feed mixtures (AS:CD) i.e (AS₀) 0:100 [Positive control], (AS₂₅) 25:75, (AS₅₀) 50:50, (AS₇₅) 75:25 and (AS₁₀₀) 100:0 [Negative Control] for 180 days using earthworm Eisenia fetida. The earthworms could thrive and grow well up to the AS₇₅ feed mixture. In the final vermicompost, there were significant decreases in electrical conductivity (29.18-18.70%), total organic carbon (47.48-22.39%), total organic matter (47.47-22.36%), and C: N ratio (78.15-54.59%). While, significant increases in pH (9.06-16.47%), total Kjeldahl nitrogen (69.57-139.58%), total available phosphorus (30.30-81.56%), total potassium (8.92-22.22%), and total sodium (50.56-62.12%). The heavy metals like Cr (50-18.60%), Cd (100-75%), Pb (57.14-40%), and Ni (100-50%) were decreased, whereas Zn (8.37-53.77%), Fe (199.03-254.27%), and Cu (12.90-100%) increased significantly. The toxicity of the final vermicompost was shown to be lower in the Genotoxicity analysis, with values ranging between (76-42.33%). The germination index (GI) of Mung bean (Vigna radiata) showed a value ranging between 155.02 and 175.90%. Scanning electron microscopy (SEM) analysis showed irregularities with high porosity of texture in the final vermicompost than in initial mixtures. Fourier Transform-Infrared Spectroscopy (FT-IR) spectra of final vermicompost had low peak intensities than the initial samples. The AS₅₀ feed mixture was the most favorable for the growth and fecundity of Eisenia fetida, emphasizing the role of cattle dung in the vermicomposting process. Thus, it can be inferred that a cost-effective and eco-friendly method (vermicomposting) with the proper amendment of cattle dung and employing Eisenia fetida could transform allopathic sludge into a nutrient-rich, detoxified, stable, and mature vermicompost for agricultural purposes and further could serve as a stepping stone in the allopathic pharmaceutical industry sludge management strategies in the future.

Biomimetic facile synthesis of zinc oxide and copper oxide nanoparticles from Elaeagnus indica for enhanced photocatalytic activity

The present study focused on synthesizing ZnO nanoparticles (NPs) and CuO NPs using Elaeagnus indica leaf extract as reducing and stabilizing agents using Zn(O₂CCH₃)₂ and Cu₂SO₄, respectively, for the first time. We have confirmed the formation of aggregated ZnO NPs and CuO NPs with phytochemicals by various spectral analyses and electron microscopy studies. The size of synthesized ZnO NPs and CuO NPs were in the range of 20-30 nm and 30-40 nm, respectively. The antimicrobial activity of ZnO NPs at 75 μg concentration is superior against Salmonella typhimurium, Klebsiella pneumonia, Bacillus subtilis, Staphylococcus epidermidis, and Aspergillus niger. While CuO nanoparticles with 75 μg concentration effectively inhibited S. typhimurium, B. subtilis, S. epidermidis, and A. niger. Phytochemicals and reactive oxygen species generated by the prepared NPs may account for the antimicrobial effects observed. The photodegradation of methylene blue by ZnO NPs and CuO NPs was 91% and 76%, respectively, for 6 h of sunlight exposure. CuO NPs and ZnO NPs have different intrinsic properties and phytochemical compositions; hence ZnO NPs photodegrade faster than CuO NPs even though ZnO has higher bandgap energy than CuO. Consequently, CuO and ZnO NPs produced from E. indica leaf extract might be utilized as antimicrobials and photocatalysts in the future.

Marine Bacteria and Omic Approaches: A Novel and Potential Repository for Bioremediation Assessment

Marine environments accommodating diverse assortments of life constitute a great pool of differentiated natural resources. The cumulative need to remedy unpropitious effects of anthropogenic activities on estuaries, and coastal marine ecosystems has propelled the development of effective bioremediation strategies. Marine bacteria producing biosurfactants are promising agents for bio-remediating oil pollution in marine environments, making them prospective candidates for enhancing oil recovery. Molecular omics technologies are considered an emerging field of research in ecological and diversity assessment owing to their utility in environmental surveillance and bioremediation of polluted sites. A thorough literature review was undertaken to understand the applicability of different omic techniques employed for bioremediation assessment using marine bacteria. This review further establishes that for bioremediation of environmental pollutants (i.e., heavy metals, hydrocarbons, xenobiotic and numerous recalcitrant compounds), organisms isolated from marine environments can be better utilized for their removal. The literature survey shows that omics approaches can provide exemplary knowledge about microbial communities and their role in the bioremediation of environmental pollutants. This review centres on applications of marine bacteria in enhanced bioremediation, utilizing the omics approaches that can be a vital biological contrivance in environmental monitoring to tackle environmental degradation. The paper aims to identify the gaps in investigations involving marine bacteria to help researchers, ecologists, and decision-makers to develop a holistic understanding regarding their utility in bioremediation assessment.

Phytoremediation of Heavy Metals: An Indispensable Contrivance in Green Remediation Technology

Environmental contamination is triggered by various anthropogenic activities, such as using pesticides, toxic chemicals, industrial effluents, and metals. Pollution not only affects both lotic and lentic environments but also terrestrial habitats, substantially endangering plants, animals, and human wellbeing. The traditional techniques used to eradicate the pollutants from soil and water are considered expensive, environmentally harmful and, typically, inefficacious. Thus, to abate the detrimental consequences of heavy metals, phytoremediation is one of the sustainable options for pollution remediation. The process involved is simple, effective, and economically efficient with large-scale extensive applicability. This green technology and its byproducts have several other essential utilities. Phytoremediation, in principle, utilizes solar energy and has an extraordinary perspective for abating and assembling heavy metals. The technique of phytoremediation has developed in contemporary times as an efficient method and its success depends on plant species selection. Here in this synthesis, we are presenting a scoping review of phytoremediation, its basic principles, techniques, and potential anticipated prospects. Furthermore, a detailed overview pertaining to biochemical aspects, progression of genetic engineering, and the exertion of macrophytes in phytoremediation has been provided. Such a promising technique is economically effective as well as eco-friendly, decontaminating and remediating the pollutants from the biosphere.

Temperature impacts fate of antibiotic resistance genes during vermicomposting of domestic excess activated sludge

Effect of temperature on antibiotic resistance genes (ARGs) during vermicomposting of domestic excess sludge remains poorly understood. Vermicomposting experiment with excess sludge was conducted at three different temperatures (15 °C, 20 °C, and 25 °C) to investigate the fate of ARGs, bacterial community and their relationship in the process. The vermicomposting at 25 °C did not significantly attenuate the targeted ARGs relative to that at 15 °C and 20 °C. The dynamics of qnrA, qnrS, and tetM genes during vermicomposting at 15 °C and 20 °C followed the first-order kinetic model. Temperature remarkably impacted bacterial diversity of the final products with the lowest Shannon index at 25 °C. The presence of the genus (Aeromonas and Chitinophagaceae) at 25 °C may contribute to the rebound of the genes (qnrA, qnrS and tetM). The study indicates that 20 °C is a suitable vermicomposting temperature to simultaneously reach the highest removal efficiency of the ARGs and the good biostability of the final product.

Accumulation capability for cesium differs among bacterial species: A comprehensive study using bacteria isolated from freshwater and coastal sediment

The fate and behavior of radioactive cesium (Cs) in the water environment are of great concern. The involvement of bacteria regarding their accumulation capability for this element is the most fundamental factor that needs to be clarified even for exploring the interactions between many environmental factors that involve together in governing the transport and distribution of Cs. As the first systematical study that aimed to evaluate the accumulation capability of environmental bacteria for Cs, bacteria in the sediment of a freshwater reservoir and coastal water environment were isolated and multiplied for contact experiment with Cs under different temperature conditions (5, 25, and 35 °C). The accumulation concentration of Cs in bacteria from freshwater sediment varied in 3.95 × 10^-6 to 5.68 × 10^-4ng-Cs/cell, and that from coastal sediment in 1.52 × 10^-6 to 7.41 × 10^-4ng-Cs/cell, indicating obvious differences among bacterial species. Bacteria of coastal sediment possessed higher accumulation capability for Cs than bacteria from freshwater sediment, and temperature dependency was confirmed for bacteria from coastal sediment. The findings of this study have great reference value for better understanding and controlling the fate and behavior of radioactive Cs associated with bacteria in the water environment.

Vermiremediation and comparative exploration of physicochemical, growth parameters, nutrients and heavy metals content of biomedical waste ash via ecosystem engineers Eisenia fetida

Vermicomposting of Biomedical waste ash (BA) by the earthworm Eisenia fetida was studied with cow dung (CD) as nutrient medium. For 105 days, experiment was carried out in seven vermireactors containing varying ratios of BA and CD. Earthworm activity significantly reduced the pH (8.61-7.24), Electrical conductivity (EC) (4.1-1.62), Total organic carbon (TOC) (38.6-14.92), and Carbon and nitrogen (C/N ratios) (145.4-8.2) of all BA ratios. Levels of Total kjeldahl nitrogen (TKN) (0.26-1.82), Total available phosphorus (TAP) (0.22-0.64), Total potassium (TK) (2.05-12.08), and Total sodium (TNa) (47.53-92.26) were found to be increasing in the postvermicompost mixture. Although heavy metals content decreased from initial to final, it becomes below the permissible limits in the end product. The results showed that earthworm growth and fecundity were best in vermireactors containing 10-25% of BA. The best reproduction and growth of earthworms, demonstrate the vermicomposting's ability to manage hazardous solid wastes like BA. Use of vermitechnology to manage BA has not been performed yet in any kind of the research. Finally, it was determined that vermicomposting can be incorporated into overall plan for BA management. Thus nutrient-rich, detoxified, and physiochemically stable product may be used safely in agricultural processes.

Comparing the nutrient changes, heavy metals, and genotoxicity assessment before and after vermicomposting of thermal fly ash using Eisenia fetida

Fly ash (FA) is available in an unstable state and can be ameliorated by vermicomposting. The different ratios of FA viz (FA₁₀, FA₁₅, FA₂₀, FA₂₅, FA₅₀, FA₇₅) were mixed with another organic waste, i.e., cattle dung. Supportive effects of FA were seen on the reproductive parameters of the earthworms up to FA₂₅. Some beneficial changes have been reported in pH, EC, TOC, TKN, TAP, TNa, TK, and potentially toxic heavy metals (Zn, Cu, Cd, Co, Ni, Cr, Pb). The genotoxicity test was performed to assess the toxic effects of the fly ash which has not been done till now. Low genotoxicity potential and high onion root growth were observed in the post-vermicompost samples which were not even reported yet by any other study. These results clearly indicated that the vermicomposting process offers the best option to manage the FA by converting it into an ecofriendly, nutrient-rich, and properly detoxified manure with the help of earthworms which also indicate its economically best-fit applications for the large scale agricultural practices.

Elimination of antibiotic resistance genes from excess activated sludge added for effective treatment of fruit and vegetable waste in a novel vermireactor

Elimination of antibiotic resistance genes (ARGs) from excess activated sludge (EAS) mixed for effective treatment of different fruit and vegetable waste (FVW) by using a novel vermireactor consisted of substrate and bed compartments was investigated. ARGs (tet G, tet M and sul 1) and mobile genetic element gene (intl 1) were targeted and, through quantitative analysis of their abundances in both the compartments and the fresh cast of earthworms, significant reductions in substrate compartments were confirmed for the treatments for FVW added with EAS and EAS alone even if the reduction extents differed among the types of FVW. Apparent reductions were not found in the bed compartment where the final products accumulated. For the fresh cast, the relative abundances of ARGs and intl 1 against to the total bacterial 16S rDNA decreased markedly. The present study provided an insight for proper controlling of ARGs during vermicomposting of FVW and EAS.

Distribution of extracellular and intracellular antibiotic resistance genes in sludge fractionated in terms of settleability

The widespread proliferation of antibiotic resistance genes (ARGs) is a serious environmental and human health issue. Wastewater treatment facilities (WWTFs) are potential sources to spread ARGs to natural environment, for which, the presence state of ARGs in the sludge, as extracellular ones (eARGs) or intracellular ones (iARGs), along with the sludge settleability, are very important factors. The sludge settleability is closely associated with its floc size and density, bacterial activity, and the proportion of intact/damaged bacterial cells that aggregate together to form flocs for separation in the sedimentation process. It is reasonable to hypothesize that the distribution of eARGs and iARGs may differ with the sludge fractions of different settleability, a topic of great academic and practical significance requiring clarification. In this study, sludge samples from the aerobic contact tank of six household WWTFs were fractionated into fractions with different settling velocities: sludge of low settleability (LS), medium settleability (MS) and high settleability (HS); and the distribution of eARGs and iARGs in the obtained fractions for the widely detected tet G, tet M and sul 1 in water environment was evaluated based on the PMA-qPCR method, together with the evaluation for the well reported mobile genomic element intl 1 and total bacterial 16S rDNA. For the LS fractions, which contained more damaged bacterial cells, the distribution percentages of eARGs were generally higher than those of iARGs. For the HS fractions, which contained flocs with larger sizes formed by both intact and damaged bacterial cells, the relative abundances of ARGs and intl 1 were found apparently lower even if the presence percentages of eARGs were comparatively higher. It is thus inferable that sludge fractions of LS may possess higher transfer potential for ARGs and enhancing their settleability through optimization of the operation conditions is important for mitigating the proliferation of ARGs.

Effect of excess activated sludge on vermicomposting of fruit and vegetable waste by using novel vermireactor

This study aimed to clarify the effect of excess activated sludge (EAS) on vermicomposting of fruit and vegetable wastes (FVW). For this, a novel vermireactor consists of substrate and bed compartments was used for treating five types of FVW (banana peels, cabbage, lettuce, carrot, and potato) with and without the addition of EAS by earthworms. The EAS promoted the growth and cocoon production of earthworms, and the decomposition efficiency of FVW. The changes of dehydrogenase activity revealed that the EAS enhanced the microbial activity in all treatments except for the carrot. The organic matter content, total carbon and the C/N ratio showed a significant decrease after addition of EAS into FVW. The content of nitrogen and phosphorus was also improved in the final products after vermicomposting. This study suggested that the addition of EAS could be a feasible option to enhance the vermicomposting of FVW.

Effect of heavy metals on the performance and bacterial profiles of activated sludge in a semi-continuous reactor

Heavy metals are toxic to microorganisms at specific concentrations and can have a serious effect on the efficiency of biological wastewater treatment plants. The wastewater treatment performance and bacterial communities of activated sludge were investigated at different heavy metal concentrations (0.1-10 mg L^-1 for Cd(II), Pb(II) and 1-100 mg L^-1 for Cu(II)) in a well-controlled semi-continuous reactor in 30 d period. Glucose was added once every 8 h as the carbon source throughout the experiment. The heavy metal toxicity was related to chemical oxygen demand (COD), total organic carbon (TOC), three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy, bacterial activity and community composition. The first-order consumption rate for glucose showed that the activity was decreasing in comparison to the control. The COD removal efficiency was also decreased from 87% to 26% in all the reactors under different heavy metal concentrations treatment. The PCR-DGGE and sequencing results revealed that the bacterial diversity showed evident variations under heavy metal stress owing to the potential toxicity of heavy metals. At the genus level, Pedobacter steynii and Flavobacterium, were only tolerant to Cu(II) at 100 mg L^-1, while Rhodanobacter thiooxydans resisted to all heavy metal concentrations except Cu(II) 100 mg L^-1. Cluster analysis and Principal component analysis (PCA) revealed that the microbial community in Cu(II) was different from the sludge samples treated with Cd(II) and Pb(II) concentrations. The study indicated that it is necessary to identify the metal tolerant species of bacteria for maintaining good performance of biological wastewater treatment plants.

Gut digestion of earthworms significantly attenuates cell-free and -associated antibiotic resistance genes in excess activated sludge by affecting bacterial profiles

Vermicomposting can significantly attenuate antibiotic resistance genes (ARGs) in the excess activated sludge (EAS). However, the effect of earthworms, especially the effect of gut digestion as a critical step in the vermicomposting process, remains unclarified. The purpose of this study was to investigate the response of ARGs (cell-free and -associated) in EAS to gut digestion of earthworms and to clarify the possible mechanism from the viewpoint of bacterial community through quantitative polymer chain reaction (q-PCR) and high throughput sequencing. Compared to the initial sludge, the earthworm casts were observed to have significantly lower absolute abundances of ARGs, especially qnrS, tetM, and tetX with the removal exceeding 90%. Cell-free and -associated ARGs (except sul1 and tetG) had equivalent contributions to the attenuation of each ARG. Remarkable reductions of bacterial number and alpha diversity (chao1 and Shannon) were detected in the casts. Spearman correlation analysis between the targeted genes and bacterial community indicates that twelve different phyla mainly including Acidobacteria, Euryarchaeota, Deinococcus-Thermus, Chlorobi, Firmicutes, Fibrobacteres, and Proteobacteria are the potential ARGs hosts, suggesting that the fate and behaviour of these hosts during gut digestion of EAS by earthworms substantially determined the dynamics of the ARGs. These findings increase our understanding of earthworm gut digestion as an important process for the attenuation of ARGs in EAS, and contribute towards preventing their release into the total environment.

Changes of quinolone resistance genes and their relations with microbial profiles during vermicomposting of municipal excess sludge

Antibiotic resistance genes abundant in municipal excess sludge reduce the agricultural value of vermicompost. However, little attention has been paid on the fate and behavior of the problem-causing agents in vermicomposting. In this study, the fate and behavior of quinolone resistance genes in excess activated sludge during vermicomposting were studied with reactors introduced with Eisenia fetida for three different densities. The substrate pile without earthworms was operated as control in parallel. The results showed that earthworms could significantly reduce the absolute abundance of quinolone resistance genes in the excess sludge, with a reduction ratio of 85.6-100% for qnr A and 92.3-95.3% for qnr S, respectively (p < 0.05). For microbial profiles, both the dehydrogenase activity and the abundance of microbes (16S rDNA) revealed a distinct decreasing trend after 7 days from the start of the experiment; however, the bacterial diversity in the final products seemed to be enriched with the emergence of the uncultured Flavobacteriales bacterium and uncultured Anaerolineaceae bacterium. Redundancy analysis revealed clearly that the qnr genes had positive correlations with the targeted indexes of microbial profiles, with the correlations with the bacterial abundance and dehydrogenase activity being more statistically significant than the bacterial diversity (p < 0.05). The results of this study suggested that earthworms could promote the attenuation of quinolone resistance genes in the excess sludge through lowering the bacterial abundance and activity, and the promotion effect could be enhanced by increasing the density of earthworms.

Bioremediation and detoxification of industrial wastes by earthworms: Vermicompost as powerful crop nutrient in sustainable agriculture

Vermicompost is the final product of the vermicomposting process involving the collective action of earthworms and microbes. During this process, the waste is converted into useful manure by reducing the harmful effects of waste. Toxicity of industrial wastes is evaluated by plant bioassays viz. Allium cepa and Vicia faba test. These bioassays are sensitive and cost-effective for the monitoring of environmental contamination. The valorization potential of earthworms and their ability to detoxify heavy metals in industrial wastes is because of their strong metabolic system and involvement of earthworm gut microbes and chloragocyte cells. Most of the studies reported that the vermicompost produced from organic wastes contains higher amounts of humic substances, which plays a major role in growth of plants. The present article discusses the detoxification of industrial wastes by earthworms and the role of final vermicompost in plant growth and development.

Amelioration and degradation of pressmud and bagasse wastes using vermitechnology

This study evaluated the amelioration of pressmud (PM) and bagasse (BG) wastes by the vermiremediation process. The wastes were spiked with cattle dung (CD) in different concentrations to find out the best proportion supporting maximum earthworm growth and nutrients availability. The highest growth rate was observed in PMBG₅₀ (282.2mg/d/worm) feed mixture. Response surface design of earthworm growth parameters enumerated best concentration of wastes in CD with maximum value of 21.81% for earthworm number, 30.86% for earthworm weight, 27.09% for cocoons, 29.71% for hatchlings and 34.0% for hatchlings weight. Vermicomposting enhanced nutrient parameters like pH (6-8%), total kjeldahl nitrogen (19-48%), total phosphorus (9-67%), total calcium (13-111%), while decrease in total organic carbon (14-32%), electrical conductivity (21-30%), C:N ratio (36-51%), total potassium (9-19%) and total sodium (3-21%). Heavy metals in the final products were found to be under safe limits. SEM micrographs were more fragmented which indicated maturity and stability.

Molecular prevalence of Babesia bigemina in Rhipicephalus microplus ticks infesting cross-bred cattle of Punjab, India

Babesiosis is an economically important tick-borne apicomplexan protozoan disease of cattle in tropical and subtropical regions. In the present study, Rhipicephalus microplus engorged female ticks were collected from 135 apparently healthy cattle from different agro-climatic zones of Punjab, India, to investigate the carrier status of Babesia bigemina infection in vector tick by using microscopy and PCR based assays. PCR when applied on DNA extracted from the egg masses harvested from ticks showed 1.48% (2/135) samples as positive, whereas 4.44% (6/135) samples were positive when product of primary PCR was used as template in nPCR. Further, among the DNA samples isolated from the unfed larval stages that emerged from egg masses laid by ticks, only 1.48% (2/135) samples were detected as positive for B. bigemina in PCR, while 7.41% (10/135) samples were detected positive in nPCR assay. Statistically, non-significant (p > 0.05) difference in prevalence rates was observed across different agro-climatic zones and between different age groups of cattle from which engorged ticks were collected. It can, thus, be concluded that prevalence of B. bigemina in the vector tick, R. microplus in Punjab state of India indicates an endemic status of the organism and a further study is needed for the management and control of the bovine babesiosis.

Genotoxicity reduction in bagasse waste of sugar industry by earthworm technology

The aim of the present study was to assess the genotoxicity reduction in post vermicompost feed mixtures of bagasse (B) waste using earthworm Eisenia fetida. The genotoxicity of bagasse waste was determined by using Allium cepa root chromosomal aberration assay. Bagasse was amended with cattle dung in different proportions [0:100 (B0) 25:75 (B25), 50:50 (B50), 75:25 (B75) and 100:0 (B100)] on dry weight basis. Genotoxic effects of initial and post vermicompost bagasse extracts were analysed on the root tips cells of Allium cepa. Root length and mitotic index (MI) was found to be increased in post vermicompost extracts when compared to initial bagasse waste. The maximum percent increase of root length was observed in the B50 bagasse extract (96.60 %) and the maximum MI was observed in B100 mixture (14.20 ± 0.60) 6 h treatment which was similar to the control. Genotoxicity analysis of post vermicompost extracts of bagasse revealed a 21-44 % decline in the aberration frequencies and the maximum reduction was found in B75 extract (44.50 %). The increase in root length and mitotic index, as well as decrease in chromosomal aberrations indicates that E. fetida has the ability to reduce the genotoxicity of the bagasse waste.

Management of Sugar Industrial Wastes through Vermitechnology

The present paper discusses the role of earthworms in recycling of sugar industrial wastes. The wastes generated from sugar industry are pressmud, bagasse, bagasse fly ash, sugar cane trash, sugar beet mud, sugar beet pulp, molasses etc. These wastes when mixed with other organic substrates become ideal mixtures for growth of earthworms. These wastes if stored in open field’s causes contamination in the environment and may cause several diseases in public health. But the governments have been unable to tackle the menace of solid waste pollution due to dearth of appropriate technologies, finance and space. Therefore, environment friendly and cost effective technologies for nutrient recycling or remediation of wastes are being advocated as an alternative means for conserving and replenishing natural resources of the ecosystems. Vermicomposting is one such technology that synergises microbial degradation with earthworm’s activity for reducing, reusing and recycling waste materials in a shorter span of time. Earthworm technology can convert sugar industrial wastes into valuable fertilizing material. The final product (vermicompost) produced during the process of vermicomposting is nutrient rich organic fertilizer with plant available nutrients such as nitrogen, potassium, calcium and phosphorus. In the present study an attempt has been made to document the role of earthworms in reuse of sugar industry waste.

Management of Sugar Industrial Wastes through Vermitechnology

The present paper discusses the role of earthworms in recycling of sugar industrial wastes. The wastes generated from sugar industry are pressmud, bagasse, bagasse fly ash, sugar cane trash, sugar beet mud, sugar beet pulp, molasses etc. These wastes when mixed with other organic substrates become ideal mixtures for growth of earthworms. These wastes if stored in open field’s causes contamination in the environment and may cause several diseases in public health. But the governments have been unable to tackle the menace of solid waste pollution due to dearth of appropriate technologies, finance and space. Therefore, environment friendly and cost effective technologies for nutrient recycling or remediation of wastes are being advocated as an alternative means for conserving and replenishing natural resources of the ecosystems. Vermicomposting is one such technology that synergises microbial degradation with earthworm’s activity for reducing, reusing and recycling waste materials in a shorter span of time. Earthworm technology can convert sugar industrial wastes into valuable fertilizing material. The final product (vermicompost) produced during the process of vermicomposting is nutrient rich organic fertilizer with plant available nutrients such as nitrogen, potassium, calcium and phosphorus. In the present study an attempt has been made to document the role of earthworms in reuse of sugar industry waste.

Molecular detection of Babesia bigemina infection in apparently healthy cattle of central plain zone of Punjab

Bovine babesiosis is an important tick-borne disease caused by the parasites belonging to the genus Babesia, distributed worldwide and infecting a wide range of domesticated and wild cattle, occasionally man. The present study was conducted to determine the prevalence of B. bigemina infection in apparently healthy cattle from central plain zone of Punjab, India. Examination of Giemsa-stained peripheral thin blood smears revealed 2.45 % (5/204) animals to be positive for piroplasms of B. bigemina. However, genomic DNA isolated from these blood samples when subjected to primary PCR revealed a positivity of 7.35 % (15/204) as detected by the amplification of a 278-bp product in the agarose gel. PCR products obtained from the primary PCR of B. bigemina, when employed as template in nested PCR produced the amplicons of desired size (170 bp) was detected in 30.39 % (62/204) of the samples. It can thus be concluded that B. bigemina infection is prevalent in apparently healthy cattle population of this region and PCR assays can serve as a valuable tool for epidemiological studies in endemic areas.

Vermistabilization of sugar beet (Beta vulgaris L) waste produced from sugar factory using earthworm Eisenia fetida: Genotoxic assessment by Allium cepa test

In the present study, sugar beet mud (SBM) and pulp (SBP) produced as a waste by-products of the sugar industry were mixed with cattle dung (CD) at different ratios on dry weight basis for vermicomposting with Eisenia fetida. Minimum mortality and highest population of worms were observed in 20:80 (SBM20) mixture of SBM and 10:90 (SBP10) ratios. However, increased percentages of wastes significantly affected the growth and fecundity of worms. Nutrients like nitrogen, phosphorus, sodium, increased from initial feed mixture to final products (i.e., vermicompost), while organic carbon (OC), C:N ratio and electrical conductivity (EC) declined in all the products of vermicomposting. Although there was an increase in the contents of all the heavy metals except copper, chromium, and iron in SBM, the contents were less than the international standards for compost which indicates that the vermicompost can be used in the fields without any ill effects on the soil. Allium cepa root chromosomal aberration assay was used to evaluate the genotoxicity of pre- and post-vermicomposted SBM to understand the effect of vermicomposting on the reduction of toxicity. Genotoxicity analysis of post-vermicomposted samples of SBM revealed 18-75% decline in the aberration frequencies. Scanning electron microscopy (SEM) was recorded to identify the changes in texture in the control and vermicomposted samples. The vermicomposted mixtures in the presence of earthworms confirm more numerous surface irregularities that prove to be good manure.

Potential utilization of bagasse as feed material for earthworm Eisenia fetida and production of vermicompost

In the present work bagasse (B) i.e waste of the sugar industry, was fed to Eisenia fetida with cattle dung (CD) support as feed material at various ratios (waste: CD) of 0:100 (B₀), 25:75 (B₂₅), 50:50 (B₅₀), 75:25 (B₇₅) and 100:0 (B₁₀₀) on dry weight basis. Co-composting with cattle dung helped to improve their acceptability for E. fetida and also improved physico-chemical characteristics. Best appropriate ratio for survival, maximum growth and population buildup of E. fetida was determined by observing population buildup, growth rate, biomass, mortality and cocoon formation. Minimum mortality and highest population size of worms was observed in 50:50 (B₅₀) ratio. Increasing concentrations of wastes significantly affected the growth and reproduction of worms. Nutrients like nitrogen, phosphorus and sodium increased from pre-vermicompost to post-vermicompost, while organic carbon, and C:N ratio decreased in all the end products of post-vermicomposting. Heavy metals decreased significantly from initial except zinc, iron and manganese which increased significantly. Scanning electron microscopy (SEM) was used to recognize the changes in texture in the pre and post-vermicomposted samples. The post-vermicomposted ratios in the presence of earthworms validate more surface changes that prove to be good manure. The results observed from the present study indicated that the earthworm E. fetida was able to change bagasse waste into nutrient-rich manure and thus play a major role in industrial waste management.

Outbreaks of thrush in pigeons in Punjab State of India

Due to high monetary turnover in business, white pigeon keeping for game purposes is gaining more popularity in Punjab. Overcrowding and poor management by undertrained naive farmers make these birds more susceptible to diseases not known so far in this region. A farmer reported that about a hundred pigeons were unable to feed properly and regurgitate feed. Birds lost body condition gradually, and three among these died. Both alive and dead pigeons were presented to the Veterinary Clinical Complex (VCC) for detailed examination. All these pigeons were found to be cachectic with wasting of breast muscles. On necropsy, no significant gross lesions were recorded in most of the visceral organs, except mottling of the liver. However, in the oral cavity, gray Turkish towel-like lesions were seen at the opening of the pharynx which continued into the larynx and proximal esophagus. Microscopic examination of material scrapped from lesions revealed a large number of budding yeast-like organisms and pseudohyphae, suggestive of Candida spp. Histologically, marked necrosis and sloughing of oral and esophageal mucosal epithelium with the presence of pyogranulomatous inflammation containing a large number of Candida organism were observed. To the authors' knowledge, there seems to be no outbreak of thrush in pigeons in Punjab previously.

Genotoxic assessment and optimization of pressmud with the help of exotic earthworm Eisenia fetida

Genotoxicity of pressmud (PM) to Allium cepa was investigated to assess its toxic potential and to elucidate the effect of vermicomposting to reduce its toxicity. The PM produced as a waste by product of the sugar cane industry was mixed with cow dung (CD) at different ratios of 0:100 (V₀), 25:75 (V₂₅), 50:50 (V₅₀), 75:25 (V₇₅) and 100:0 (V100) (PM:CD) on a dry weight basis for vermicomposting with Eisenia fetida. Different concentrations of 100% PM sludge extract (10%, 20%, 40%, 60%, 80% and 100%) and negative control (distilled water) and positive control (maleic hydrazide) were analyzed with A. cepa assay to evaluate frequency of chromosomal aberrations before and after vermicomposting. Percent aberration was greatest (30.8%) after exposure to 100% PM extract after 6 h but was reduced to 20.3% after vermicomposting. Exposure to the extract induced c-mitosis, delayed anaphase, laggards, stickiness and vagrant aberrations. Microscopic examination of root meristem exposed to PM sludge extract showed significant inhibition of mitotic index. Also, the mitotic index decreased with increase in concentration of PM sludge extract. After vermicomposting the mitotic index was increased. However, increasing percentages of PM significantly affected the growth and fecundity of the worms and maximum population size was reached in the 25:75 (PM:CD) feed mixture. Nitrogen, phosphorus, sodium, electrical conductivity (EC) and pH increased from initial feed mixture to the final products (i.e., vermicompost), while organic carbon, C/N ratio and potassium declined in all products of vermicomposting. Scanning electron microscopy (SEM) was recorded to identify the changes in texture with numerous surface irregularities and high porosity that proves to be good vermicompost manure. It could be concluded that vermicomposting could be an important tool to reduce the toxicity of PM as evidenced by the results of genotoxicity.

Coprological investigation on neonatal bovine cryptosporidiosis in Ludhiana, Punjab

An overall prevalence of 38.90 % was recorded for bovine cryptosporidiosis on coprological examination of 144 faecal samples collected from neonatal cattle calves from organised dairy farms in and around Ludhiana, Punjab by modified Ziehl-Neelsen staining. Further, a gradual decline in the percent prevalence was seen with increase in the age of the host from <1 month (64.1 %) to 4-5 months (12.5 %). The highest prevalence was recorded during the monsoon season (47.06 %) followed by summer (37.73 %) and winter (30.0 %) season and the seasonal variation was statistically significant (p ≤ 0.05). Female calves showed higher prevalence (44.32 %) than their male counterparts (27.66 %). Further, prevalence of cryptosporidiosis was significantly higher (p ≤ 0.05) in the diarrhoeic calves (52.70 %) as compared to the non-diarrhoeic (24.28 %) thus indicating a relatively higher risk (1.75 times) of the disease in diarrhoeic than normal calves.

Vermiremediation of dyeing sludge from textile mill with the help of exotic earthworm Eisenia fetida Savigny

The aim of present study was for the vermiremediation of dyeing sludge from textile mill into nutrient-rich vermicompost using earthworm Eisenia fetida. The dyeing sludge was mixed with cattle dung in different ratios, i.e., 0:100 (D0), 25:75 (D25), 50:50 (D50), 75:25 (D75), and 100:0 (D100) with earthworms, and 0:100 (S0), 25:75 (S25), 50:50 (S50), 75:25 (S75), and 100:0 (S100) without earthworms. Minimum mortality and maximum population build-up were observed in a 25:75 mixture. Nitrogen, phosphorus, sodium, and pH increased from the initial to the final products with earthworms, while electrical conductivity, C/N ratio, organic carbon, and potassium declined in all the feed mixtures. Vermicomposting with E. fetida was better for composting to change this sludge into nutrient-rich manure.

Comparison of nested PCR and microscopy for the detection of cryptosporidiosis in bovine calves

The comparative efficacies of different conventional parasitological methods and nested PCR for diagnosis of bovine cryptosporidiosis in faecal samples were evaluated. Among the 100 samples collected from calves in and around Ludhiana Direct faecal smear staining technique revealed 25.0 % positivity for the oocysts of Cryptosporidium spp. with sensitivity and specificity of 68.12 and 92.98 %, respectively. Zinc sulphate solution floatation and saturated sugar solution floatation staining techniques showed sensitivity and specificity of 83.92 and 96.36; 81.03 and 98.14 %, respectively. Products of the primary PCR of Cryptosporidium spp. directed against small subunit (18S) ribosomal RNA when employed as template in nested PCR produced the amplicons of desired size (834 bp) in 47.0 % of the samples. Amplification of 834 bp fragment was also observed in positive control, while no amplification was observed in negative control. Results indicated PCR assays as highly sensitive and specific techniques for the screening of the samples for Cryptosporidium spp. but in developing countries and under field conditions where limited resources do not allow the application of PCR assays, concentration staining methods are recommended.

Novel antibodies in the treatment of non-Hodgkin's lymphoma

Monoclonal antibodies (mAbs) have revolutionised the treatment of malignancies, especially non-Hodgkin's lymphoma (NHL). Antibody-based therapies target tumour cells expressing a specific antigen while sparing the majority of normal cells leading to a decrease in treatment-associated toxicity. Rituximab, a monoclonal antibody directed against CD20 on B cells, was the first monoclonal antibody to be approved by the US Food and Drug Association (FDA) in 1997 for the treatment of patients with relapsed/refractory, follicular or low-grade NHL . However, it was soon realised that not all patients respond to rituximab therapy and close to 60% of patients with follicular lymphoma who were previously sensitive to rituximab become 'resistant' to repeat rituximab therapy. This led to further attempts to improve the antitumour activity of anti-CD20 mAbs (i.e. 2nd/3rd generation anti-CD20s), and to identify additional potential targets on lymphoma cells other than CD20. A number of these antibodies directed against lymphoma cell targets other than CD20 are now undergoing development, many of which are currently in clinical trials. This manuscript focuses on an overview of these 'non-anti-CD20' novel mAbs for NHL.