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The present research focuses on addressing various ambiguities in the existing method of integrating information entropy and water quality, thereby presenting a novel approach for an entropy-weighted water quality index. A three-dimensional water quality dataset is considered in the proposed method, the third dimension being the sampling frequency factor. The probability of observed values adhering to desirable limits prescribed by a standard code is estimated, leading to the computation of information entropy and, eventually, entropy weights. These weights are then used for the computation of the Modified Entropy-weight Water Quality Index (MEWQI) values. To verify the proposed method’s applicability, the water quality dataset of Deepor Beel, India, was considered. IS 10500: 2012 was used for estimating MEWQI values. Results showed an excellent correlation with the observed dataset and their uncertainties of occurrence. The reliability and correctness of the proposed methodology were finally confirmed through both cluster analysis and sensitivity analysis. The cluster analysis showed remarkable associations with the computed MEWQI values, while the sensitivity analysis proved that no particular parameter was accountable for the contribution of MEWQI values; instead, all parameters exhibited equal contributions. The proposed methodology was thus found to be the most reasonable and reliable as it considered both factors, i.e., measured values concerning standard limits and the uncertainty, necessary for a consistent water quality monitoring program.

The current study investigates on correlating the heavy metal contamination, its distribution, and the human health risk associated with all three components of an aquatic ecosystem. For this purpose, water, sediment, and fish samples (three species, notably Notopterus notopterus, Clarias batrachus, and Channa striata) from Deepor Beel were considered, and their heavy metal contamination and distribution were determined. The corresponding health risks were then evaluated for six different heavy metals; Cr, Cd, Fe, Mn, Cu, and Pb. Pb and Mn were found to significantly impact the non-carcinogenic human health risks for the water column. Simultaneously, Cd was considered to possess the highest potential for both carcinogenic and non-carcinogenic health effects in the sediment column. Cd also played a critical role in the fish samples' bioaccumulation factor, with the liver showing the maximum bioaccumulation potential. Furthermore, children were found to have considerably higher effects (both carcinogenic and non-carcinogenic) than adults. Finally, the sediment column was found to substantially contribute to the bioaccumulation factor in the fish biota, compared to the water column. The results of this investigation will thus prove consequential in designing, monitoring and restoring aquatic ecosystems.

Water quality monitoring programs are indispensable for developing water conservation strategies, but elucidation of large and random datasets generated in these monitoring programs has become a global challenge. Rapid urbanization, industrialization and population growth pose a threat of pollution for the surface water bodies of the Assam, a state in northeastern India. This calls for strict water quality monitoring programs, which would thereby help in understanding the status of water bodies. In this study, the water quality of Baralia and Puthimari River of Assam was assessed using cluster analysis (CA), information entropy, and principal component analysis (PCA) to derive useful information from observed data. 15 sampling sites were selected for collection of samples during the period May 2016- June 2017. Collected samples were analysed for 20 physicochemical parameters. Hierarchal CA was used to classify the sampling sites in different clusters. CA grouped all the sites into 3 clusters based on observed variables. Water quality of rivers was evaluated using entropy weighted water quality index (EWQI). EWQI of rivers varied from 61.62 to 314.68. PCA was applied to recognise various pollution sources. PCA identified six principal components that elucidated 87.9% of the total variance and represented surface runoff, untreated domestic wastewater and illegally dumped municipal solid waste (MSW) as major factors affecting the water quality. This study will help policymakers and managers in making better decisions in allocating funds and determining priorities. It will also assist in effective and efficient policies for the improvement of water quality. Highlights Evaluation of water quality using entropy weighted WQI.; Entropy provides valuable descriptions of random processes.; Classification of sampling sites by using Hierarchal cluster analysis based on observed parameters.; Application of principal component analysis to recognize the latent pollution sources.; Study will assist policy makers to make better decisions for surface water quality management.

Present study evaluated the surface water quality of Kameng River (Assam, India). Kameng River is the tributary of the river Brahmaputra, having its confluence at its north bank. Water samples were collected from 9 different locations along the stretch and 24 parameters were analysed. Water quality at all sampling sites was expressed in terms of overall index of pollution (OIP). The OIP of all sampling sites varied between 1.30 and 1.74. Principal component analysis (PCA) was used to identify the latent factors influencing the water quality of the river. PCA revealed that domestic wastewater and agricultural runoff were the leading sources causing adulteration of the river's water quality. The degree of contamination of each sampling site due to heavy metals was calculated by the contamination index and an associated human health risk assessment was done by computing average daily intake and Hazard quotient (HQ). The HQ of all sampling sites varied from 0.14 to 1.21. This work presents the reliability and practicability of the integrated use of these approaches in river water quality monitoring and assessment. These methods will be very useful for policy makers for assessing the cause and effect of pollution of water bodies and implementing policies to keep pollution under check.

The present study uses four Environmetrics tools: hierarchical cluster analysis (HCA), discriminant analysis (DA), principal component analysis (PCA), and positive matrix factorization (PMF) for the assessment of water quality and geochemistry of Deepor Beel, Assam, India. The hierarchical clustering classified the 23 sampling locations into three clusters, classifying them as sites of high, low, and moderate contamination respectively. The DA of the water quality dataset resulted in 9 parameters (EC, TDS, TSS, , Na+, Mg, Cd, Pb and OrgN), primarily responsible for the discrimination of the clusters. PCA was then employed on the normalized dataset for the identification of potential pollution sources. PCA yielded two significant principal components, describing anthropogenic and natural factors defining the water contamination. Finally, PMF was employed on the dataset matrix, with four pre-defined factors. Leaching from Boragaon landfill site, surface water runoff, discharge of effluents from the industries in the wetland and discharge from Basistha River were found to be the major contributors. The results of this study provide a comprehensive correlation between water quality parameters and their sources, which would thereby assist in better planning and management of wetland restoration.

Pretreatment plays an important role in enhanced methane production from lignocellulose material. In this study, four different types of heating processes such as hot air oven, autoclave, liquid hot water bath, and microwave oven were used for comparison. The study was carried out in a biochemical methane potential assay to evaluate the different thermal heating process for enhanced methane production. Methane yield was increased in varied proportions with reduced digestion time for different heating processes of thermal pretreatment with low heating temperature at high residence time. Hot air oven pretreatment (17.92%) showed a high yield of methane production followed by autoclave (13.44%), microwave oven (9.54%), and hot water bath (7.54%) than control samples. In addition, the effect of pretreatment on biodegradability was assessed with three different kinetic models. Modified Gompertz model presents similar experimental data with a high degree of best fit when compared with the other two models.

The primary motivation behind this study was to explore the energy potential of the residual defatted microalgae biomass by anaerobic co-digestion with rice straw (RS). Two defatted microalgae species Chlorella CG12 and Desmodesmus GS12 were co-digested with RS at C/N ratio of 30. A considerable cumulative biomethane yield of 382 mL/g-VS obtained in the co-digestion of CG12 + RS followed by GS12 + RS (311 mL/g-VS) shows 49.87% and 22.26% increment, respectively, as compared to the control. The sludge on the 40th day of the anaerobic digestion was reutilized to cultivate the fresh batch of microalgae. The microalgal growth was studied at a light intensity of 3000 Lux, 22 ± 2 °C and pH of 7–7.5. The maximum lipid content of 19% on a dry cell weight basis (dcw) was seen at 20% sludge concentration in GS12. Total microalgal biomass was found to be increased by 22% compared to the control, i.e., in BG-11 media. This combined use of microalgae with RS helped in enhanced energy recovery. It also provides a sustainable approach for the development of a microalgae-based biorefinery for the production of biodiesel and biogas as an energy fuel.

Microorganisms play an important role in arsenic (As) cycling in the environment. Microbes mobilize As directly or indirectly, and natural/geochemical processes such as sulphate and iron reduction, oxidative sulphide mineral dissolution, arsenite (AsO33-) oxidation and arsenate (AsO43-) respiration further aid in As cycle in the environment. Arsenate serves as an electron donor for the microbes during anaerobic conditions in the sediment. The present work reviews the recent development in As contamination, various As-metabolizing microbes and their phylogenetic diversity, to understand the role of microbial communities in As respiration and mobilization. It also summarizes the contemporary understanding of the intricate biochemistry and molecular biology of natural As metabolisms. Some successful examples of engineered microbes by harnessing these natural mechanisms for effective remediation are also discussed. The study indicates that there is an exigent need to have a clear understanding of environmental aspects of As mobilization and subsequent oxidation-reduction by a suitable microbial consortium.

This study emphasizes the use of different thermal pretreatment methods (i.e., hot air oven, hot water bath, autoclave and microwave) on pretreatment of rice straw prior to anaerobic degradation. These pretreatment methods resulted in reasonably high solubilization of recalcitrant biomass. Maximum solublisation was attained by microwave (190 °C; exposure time-4 min) (66.6%) followed by autoclave, hot air oven and hot water bath methods. Accelerated cumulative methane yield of microwave pretreated sample achieved was 367.71 mL/g-VSadded, which was 160.68 mL/g-VSadded higher than the control. Combining this high temperature conditions with lesser exposure time also improved the energy balance of the process. The physicochemical characteristics of pretreated rice straw were investigated by Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD), FESEM analysis showed the increased porosity of the rice straw, FTIR analysis showed the omission of hemicellulose from the matrix and with XRD analysis reduced value of crystallinity index supports the destruction of the crystalline matrix.

The present study aims at providing a novel technique for assessment of heavy metal contamination in a water body employing information entropy. For this purpose, 8 different locations, each from four tributaries of Brahmaputra river, Beki, Manas, Baralia and Pagladia, were chosen. Water samples from these tributaries were collected and analyzed for iron (Fe), manganese (Mn), lead (Pb), chromium (Cr), zinc (Zn) and copper (Cu) using atomic absorption spectroscopy (AAS). Information (Shannon) entropy was employed to assign weights to each heavy metal which was then coupled with the sub-indices to evaluate the entropy weighted heavy metal contamination index (EHCI). Spatial trend of EHCI values indicated that the water quality of Beki and Baralia river was either “excellent” (EHCI 100). Similar trend was observed for Pagladia river. A comparative approach was also carried out among all the heavy metal contamination indices to decide the efficacy of EHCI. The results indicated major conflicts between the indices at various sampling locations, and thus, it was evident from the water quality dataset that EHCI provided a better insight to the classification of water quality with respect to heavy metals. The study would thus be of significant aid in scientific research of stream restoration and water treatment strategies.

Invasion of Lantana camara all over the world and its management is a global problematic issue. Its rapid growth and competition with natural resources such as space, water, and nutrients of other ...

Mixing and the separation of stages in a digester during anaerobic digestion demonstrate enhanced biodegradation efficiency of the feedstock. But two stage anaerobic digesters are difficult to operate and require huge space. Also, continuous high intensity mixing minimises biogas production. Based on these criteria, a novel type of two stage anaerobic digester was designed. The aim of this study was to evaluate the performance of this novel anaerobic digester in continuous mode utilising water hyacinth as the feedstock. Initially, untreated water hyacinth whole plant was fed in the digester followed by hot air oven pretreated water hyacinth and water hyacinth co-digested with food waste. The optimal OLR for untreated and pretreated water hyacinth was observed to be 3.75 kg COD/m3.d whereas for co-digested water hyacinth the optimal OLR was 6.7 kg COD/m3.d; illustrating an average COD removal of 72.5%, 82% and 77% for untreated, pretreated and co-digested water hyacinth respectively.

Water quality has always remained paramount when it comes to sustainable development. The most convenient method of determining the health of a particular water body is through water quality indexing. Based on the filtered 2049 articles published, the present review-based study was conducted for a science-based mapping to evaluate the research in the domain of water quality indexing until 2020. A three-stage sequential process; bibliometric examination, scientometric investigation, and qualitative valuation resulted in the identification of the most influential and productive journals, researchers, articles, and countries dynamic in the research field. Keyword analysis further revealed that groundwater quality assessment for drinking water has been the key focus of research among scholars. The scientometric analysis was followed by a qualitative discussion on the current topics of research; mainly categorized into four classes, i.e., specific indices, human intervention, performance assessment and emerging technologies, and also highlighting some of the significant research gaps. This was followed by presenting a research framework wherein, plausible future directives were proposed. This study thus provides a more comprehensive picture on the existing researches carried out in the domain of water quality indexing, identifying the primary gaps and thereby providing multi-disciplinary guidance for various researchers and practitioners linked to the current research to the future.

The presence of toxic chemicals in landfill deteriorates the quality of liner material by affecting its adsorption capacity and hydraulic properties. In this study, the influence of variou...

Anthropogenic contamination, including the adaptation of sophisticated agricultural methodologies, has rendered a steep decline in the water and soil quality across the globe. This, in turn, has adversely affected the crop productivity. Hence, to utilize water from a source, a review assessment regarding the water suitability is essential. The present study proposes a new irrigation-based water quality index (IWQI), integrating statistics; hierarchical cluster analysis (HCA) and principal component analysis (PCA), to specific water use. Twenty-three sampling locations were chosen for analyses of 13 water quality parameters from October 2017 to February 2019 from Deepor Beel, Assam, to determine the efficacy of the proposed water quality index. HCA divided the 23 locations into 3 clusters, after which, PCA for each independent cluster provided component scores. These component scores were then used to estimate weights for each parameter for all the 23 locations. The IWQI categorized all the sampling locations as “Very Good”, thereby rendering them fit for irrigation. This was validated through the use of various irrigation parameters, such as sodium adsorption ratio (SAR), Kelly’s ratio (KR), soluble sodium percentage (SSP), residual sodium carbonate (RSC), permeability index (PI), and magnesium adsorption ratio (MgR). USSL and Wilcox plots were also considered for the correlation. IWQI was observed to provide an excellent association with all the parameters. Thus, the study would prove fruitful in establishing long-term and extensive management plans to the conservation of natural water resources.

The present study demonstrates the efficacy of information entropy for the development of water quality index (WQI) for irrigation purpose and its application on Bharalu River. Water quality for irrigation suitability was assessed by using derived parameters such as permeability index (PI), Kelly’s ratio (KR), magnesium adsorption ratio (MgR), sodium adsorption ratio (SAR), soluble sodium percentage (SSP), and residual sodium carbonate (RSC) using annual data from April’2008 to April’2013 and April’2016, April’2017 over a period of 8 years. Values obtained in the study varied from 1.85 to 39.35% for SSP, 0.08 to 1.37 for SAR, 31.7–60.0% for MgR, 0.0–5.45 for RSC, 0.33–2.36% for PI, an 0.01–0.52 for KR. The derived parameters values indicate that water of Bharalu River is suitable for irrigation except April’2008 and April’2011. United States Salinity Laboratory (USSL) and Wilcox diagrams were used for categorizing of water quality. USSL and Wilcox diagrams categorized the water samples as S1-C2 and S1-C3, and ‘Excellent to Good’ and ‘Good to Permissible’ respectively, which suggest River Bharalu’s irrigation suitability. Entropy weighted irrigation water quality index (EIWQI) has been proposed and applied on Bharalu River data for assessing its suitability and variability for irrigation. EIWQI was found to be less than 1 for all the years except April’2011, which showed its appropriateness for irrigation. This study can be of great help for policymakers and researchers to effectively manage water resources.

Composting of the Hydrilla verticillata, an invasive aquatic weed, signifies aquatic waste management as a safe and hygienic method that produces a nutrient-rich end product, i.e., compost. However, its higher moisture content, higher N-losses, and lower degradation rate have shown negative impacts on the composting process. Therefore the primary objective of this study was to assess the composting physics and the degradation kinetics after addition of three different carbon-rich agents with Hydrilla verticillata. To pursue this objective, three carbon-rich agents (viz. dry leaves in Run A, grass clippings in Run B and wood chips in Run C) each were mixed (10% w/w) to the optimized control mixture of Hydrilla verticillata, cow dung and sawdust (8:1:1) as reported in the earlier study. The composting experiments were performed in 550L rotary drum composter for 20 days to evaluate variation in physical, chemical, nutritional properties as well as degradation kinetics. The Run A and Run B were the only two mixtures that attained the temperature (55–70 °C) that indicates standard sterilization capacity in both with maximum moisture reduction (17%) and total Kjeldahl N increment (48%) in the latter. Organic matter losses throughout the process followed a first-order kinetic equation in all the Run (A-C) and control with the higher loss in Run B whereas least in control. Nevertheless, the addition of all carbon-rich agents is found to be beneficial to improve composting physics. Amongst all Runs (A-C), Run B achieved maximum reduction in the initial value of bulk density (64%) and increment in the initial value of free air space (20%). The study also concluded that all the carbon-rich agents have produced compost with the nutritional concentration suitable for agricultural proposes.

Biogas has become an alternative clean source of energy. Agricultural residues being renewable and abundant resources could be efficiently used as a feed for methane production. The recalcitrant behaviour of rice straw marks pretreatment an important step to facilitate the transformation into renewable (methane) energy source. Microwave pretreatment has been considered as one of the most effective method, as it can directly (thermal and nonthermal effects) react with the feedstock and destroy its complex matrix. The present study considered the different temperature and exposure time (i.e., 130–230 °C, 2–5 min). Biochemical methane potential was assessed corresponding to the maximum solubilization rate; specific methane yield was obtained as 325.76 mL/g/VS. The total net energy gain of 3288.576 J/g/VS was obtained. The performance parameters were calculated by using different kinetic models. It followed the trend as modified Gompertz > transference function > logistic function models. Field Emission Scanning Electron Microscopy (FESEM) and Fourier Transform Infrared (FTIR) analysis confirmed the breakdown of lignocellulose structure resulting from the rupture of cuticular surface.

The lower moisture content and bulk densities characterize the Biochar. It is rich in carbon and possesses higher porosity. Utilization of Biochar during composting of various organic wastes successfully improved the efficacy of the composting process, degradation rate, and final product quality. However, the composting physics during the composting of lignocellulose aquatic waste is rarely studied. Hence the objective of this research is to assess the impact of biochar addition (0 and 2.5% w/w) to a mixture of Eicchornia Crassipes, cow dung, and sawdust. The study provides an insight of composting physics, percentage improvement rate of degradation of organic matter, and the cation-exchange capacity. As a result of Biochar addition, the thermophilic (57.3 °C) temperature lasted for more than three days. The Biochar addition decreased the bulk density by 7% in the initial feedstock. It also aided in increasing the initial value of the free air space and porosity of the mixture. The study noted a strong relationship amongst physical parameters and the significant correlation of degradation of organic matter with moisture content and bulk density (p

Optimizing between information needs and information gathered from water quality monitoring networks involve complicated decision making processes and management strategies. The present study investigates upon entropy based variability of water quality using disorder indices. Employing the Shannon's diversity index and the principle of maximum entropy (POME), the study identifies locations which have encountered the highest influence of cumulative factors such as discharge of sewage, lowering of water table, dilution and surface run-off, which lead to water quality variability in a waterbody over a monitoring period. A case study on 19 sampling locations over the monitoring period of 2017-2018 has been done on the entire expanse of Deepor Beel (DB), a wetland of international importance designated as a Ramsar site in 2002. Geospatial analysis and isoinformation lines have been employed to generate geospatial maps that clearly depict ideal monitoring locations which encountered highest variability in their water quality over the monitoring period with respect to physico-chemical parameters, BOD, COD and heavy metals. Results indicated 5 sampling locations DB1, DB10, DB11, DB12 and DB18 for physico-chemical parameters and 4 sampling locations DB1, DB4, DB15 and DB17 for heavy metals encountered highest variability and are recommended ideal monitoring locations. The present study introduces an innovative approach to derive maximum useful information by pinpointing sampling stations for regular monitoring purposes. Risk assessment due to heavy metals was also done by using average daily dose and hazard index in the monitoring period. Cr and Pb were critical to human health on consumption.

The aim of this study was application of multivariate statistical techniques – e.g., hierarchical cluster analysis (HCA), principal component analysis (PCA) and discriminant analysis (DA) – to analyse significant sources affecting water quality in Deepor Beel. Laboratory analyses for 20 water quality parameters were carried out on samples collected from 23 monitoring stations. HCA was used on the raw data, categorising the 23 sampling locations into three clusters, i.e., sites of relatively high (HP), moderate (MP) and low pollution (LP), based on water quality similarities at the sampling locations. The HCA results were then used to carry out PCA, yielding different principal components (PCs) and providing information about the respective sites' pollution factors/sources. The PCA for HP sites resulted in the identification of six PCs accounting for more than 84% of the total cumulative variance. Similarly, the PCA for LP and MP sites resulted in two and five PCs, respectively, each accounting for 100% of total cumulative variance. Finally, the raw dataset was subjected to DA. Four parameters, i.e., BOD5, COD, TSS and SO42− were shown to account for large spatial variations in the wetland's water quality and exert the most influence.

The present study is a comparative evaluation of anaerobic co-digestion of water hyacinth and food waste with and without pretreatment. The novelty of this anaerobic co-digestion study is that it highlights the effect of pretreatment and mixing ratio. Two set up of bio-chemical methane potential (BMP) experiments for the same mixing ratios but with or without pretreatment were simultaneously conducted. In set I, untreated water hyacinth and food waste was co-digested whereas in set II, pretreated water hyacinth and food waste was co-digested. Higher biogas production in set I and II was witnessed by the mixing ratios 2 and 1.5 respectively indicating them to be the ideal mixing ratio. Considerably higher biogas production was observed for both the setup of anaerobic co-digestion than mono-digestion. Also, set II exhibited higher biogas production than set I. The results portrayed that pretreatment followed by co-digestion provided quicker and higher biogas production.

Green synthesis of metallic nanoparticles is techniques to diminish the generation of by-product, chemical reagents, and toxic solvents etc. that are having negative impacts not only on the environment but also on human health. In this study, the ability of the tea waste extracts was scrutinized as novel reducing agents for the green synthesis of iron nanoparticles (FeNPs). Synthesized TW-FeNPs were analyzed by scanning electron microscope (SEM) and found that the average particle size was 98.79 nm. The analysis of TW-FeNPs by Fourier Transform Infrared Spectrophotometer (FTIR) represented the presence of different functional groups that are responsible for Phenol Red (PR) adsorption. The adsorption kinetics of PR on the TW-FeNPs regarding the initial dye concentration, different pH, adsorbent dosages, and temperature were investigated. Results show that adsorption of PR was reduced with increasing initial dye concentration and temperature. Most favorable removal of PR was achieved at pH 8.0 (94.9%) as compared to the acidic and alkaline pH. The equilibrium data was found to be fitted well with Langmuir Isotherm model in comparison with Freundlich isotherm model. The results revealed that pseudo second order kinetic model describe the kinetic data well. In the UV region a sharp adsorption band occurs between 190–250 nm. The particle size of TW-FeNPs was observed in the range of 30–190 nm determined by Zeta nanosizer. The adsorption capacity of PR on TW-FeNPs was increased significantly from 47.8 to 218.4 mg/g with an increasing initial concentration of PR from 10 to 40 mg/L at pH 8. The waste tea extract have a positive effect on the adsorption capacity of PR on to the TW-FeNPs. Removal efficiency of PR was observed higher with TW-FeNPs as compared to the chemically synthesized FeNPs.

Biological pretreatment with novel isolated microbial pure culture was utilised to pretreat water hyacinth to enhance its solubilisation followed by biogas production. Lignocellulose degrading bacterial strains isolated from soil (Bordetella muralis VKVVG5) (UN3d2), the gut of silverfish (Citrobacter werkmanii VKVVG4) (SFa2) and millipede (Paenibacillus sp. VKVVG1) (BrB2) were employed to optimise the ideal bacterial strain illustrating accelerated hydrolysis of water hyacinth. Citrobacter werkmanii VKVVG4 pretreatment of water hyacinth with an optimum dosage of 109 CFU/mL and time of 4 days helped in achieving the highest solubilisation of 33.3%. Biochemical methane potential (BMP) test was conducted between untreated and Citrobacter werkmanii VKVVG4 pretreated water hyacinth. Biochemical methane potential (BMP) test of pretreated water hyacinth illustrated faster start up period than the untreated water hyacinth. Citrobacter werkmanii VKVVG4 (SFa2) pretreated water hyacinth illustrated a cumulative biogas production of 3737 ± 21 mL whereas untreated water hyacinth illustrated a cumulative biogas production of 3038 ± 13 mL on the 50th day. Scaled up batch (20 L) study demonstrated a three times increase in the cumulative biogas generation of the microbial pretreated water hyacinth than the untreated water hyacinth.

Invasive aquatic weed management is one of the biggest challenges in the field of solid waste management. Eichhornia crassipes , Pistia stratiotes and Hydrilla verticillata (L.f.) Royle pose some of the world's most noted aquatic weed problems. Previously reported studies on management of H. verticillata , a submersed aquatic plant, have shown that temporary removal, chemical treatment or biological control methods each have advantages and disadvantages. Removal programs that propose to compost harvested H. verticillata biomass may provide a novel technique to manage this issue. However, the properties of such compost as an agriculture resource are unclear. This study presents the different mix proportions of H. verticillata , cow dung and sawdust used for the composting of 550 L rotary drum composter. This work characterizes the biological, physicochemical, and respirometry properties of the various mixes over a 20-day composting period. The results suggest that the biomass of H. verticillata can be beneficially utilized to produce stable compost for potential use in agricultural systems.

Over the decades, composting is a superlative technology to manage organic wastes such as vegetable wastes, sewage sludge, industrial wastes, and aquatic weeds as a soil conditioner. This study focuses on the use of hydrilla verticillata as a substrate material, mixed with cow dung, and sawdust. The combined addition of cow dung and sawdust improved the conditions of the composting process and the quality of compost. Along with, conventional parameters such as volatile solids, pH, total nitrogen, and stability parameters this study also describes the proper understanding of process fundamentals about few important physical parameters such as bulk density, particle density, free air space, and moisture content. These parameters were studied during composting of highly invasive aquatic weed (H. verticillata) in 550 L rotary drum composter. Thermophilic phase (>45 °C) was reached within 24 h of feeding; volume reduction was clearly depicted as, bulk density also increased from 171 to 761 kg m−3 during 20 days composting process. However, the study reveals that particle density of compost varied from 1079.1 to 2313 kg m−3 during composting. Proficient compost production involves detailed understanding the process dynamics of correlation between moisture reductions, free air space, bulk density, and particle density. Few physical properties during composting of H. verticillata are compared with other aquatic weeds reported in literature.

Ageratum conyzoides is a rapidly colonizing invasive alien terrestrial weed that has become troublesome all over the world. This noxious weed shows adverse effects on the rice fields, which is a staple food crop in many countries, and it increases the productivity cast, hence this weed needs to be managed in a systematic way. This study was performed to identify the ideal food to microorganism (F/M) ratio for maximum methane production. BMP assay revealed that, F/M ratio 2 acquired maximum biogas production from the anaerobic digestion of A.conyzoides biomass with cow dung as the microorganism source. Highest methane production was achieved on 25th day around 205 ± 10 mL CH4/g VS (volatile solid) and cumulative biogas production reach up to (4994 ± 25 mL). 80% of the total biogas produced was achieved within the first 30 days. Highest Volatile solid reduction was observed in F/M ratio 2 (45.30%) as compared to other ratios. Volatile fatty acid (VFA) and Soluble chemical oxygen demand (sCOD) also found to be highest in F/M ratio 2. In kinetic study, M value was found to be 4.0000 L CH4 in ratio 2.

Strenuous efforts are being made to make the manufacturing activities sustainable. Consequently, industries are seeking ways not only to reduce energy consumption, waste accumulation and carbon footprint but also to reduce exploitation of precious natural resources. Fertile soil is one such precious resource which is being used for brick manufacturing for centuries. Brick industry needs frugal innovations to accommodate large quantities of waste and to make the production processes sustainable. Numerous studies in the past have tried to recycle waste materials by incorporating them into the brick production cycle. This experimental feasibility study is first to demonstrate the use of aquatic weed (water hyacinth) in brick manufacturing. Using chemical-mineralogical and physical-mechanical characterization, optimal mixing ratio of water hyacinth (WH) and soil was determined for achieving the desirable mechanical properties (compressive strength and water absorption) of a fired clay brick compliant with Indian and ASTM standard codes. XRD results confirmed that addition of WH does not cause compositional changes in the phase and leads merely to an increased porosity in bricks. An optimum mix of 10% WH with soil and a firing temperature of 900 °C were found appropriate for brick production using WH as a partial substitute to the soil. Greenhouse gas (CO2) emission during firing was ascertained and it was estimated that incorporation of 10% WH leads to 7% net saving in the consumption of external fuel required for firing the bricks.

Management of industrial sludge is a big challenge for developing countries. Composting is an economical and viable option to manage and treat an industrial sludge. However, efficient compost production requires nature of materials involved, process understanding and physics behind the process. We investigated the physical parameters during composting of solid pulp and paper mill sludge in 550 L rotary drum composter. Variation in physical parameters such as bulk density, volatile solids, moisture content, free air space, void ratio, ash content and particle density were analyzed over the period of composting. Bulk density was observed increasing, whereas free air space was showed declining trend and observed 52% in end compost. The particle density was observed to be increasing from 610 to 680 kg m−3. End compost was analyzed for nutritional parameters and seen to be increasing over the period of composting. A strong relationship was found between various physical parameters. Pearson’s correlation coefficient matrix was formed between free air space, bulk density, moisture content and particle density.

Water hyacinth is a deadly weed in an aquatic environment but a potential feedstock for the generation of renewable biogas through anaerobic digestion. Biochemical methane potential (BMP) was examined for fresh water hyacinth whole plant after microbial pretreatment to determine the ideal food to microorganism (F/M) ratio. The study revealed that after microbial pretreatment of water hyacinth the F/M ratio 1.5 showed the highest methane yield of 156 ± 19 mL CH4/g VS on the 20th day. It was observed that the microbial pretreated water hyacinth illustrated enhanced biogas production within a short time period when compared to the untreated water hyacinth. The ideal F/M ratio played a significant role alongwith the microbial pretreatment process to accelerate the hydrolysis period and increasing biogas generation.

Hydrilla verticillata, an invasive aquatic weed is found to be a complex worldwide. Chemical and biological treatments can be applied for its growth retardation, but it may affect the quality of water, ultimately affecting aquatic lives. Previously reported studies proposed that the H. verticillata can be managed and utilized using advanced techniques that changed the approach towards it from nuisance to useful resource. It has been proved to be protein-rich and hence can be used as fodder for cattle. Exploring the feasibility of H. verticillata has become prime importance in any of the application of it. However, there is a need to research on large-scale management and utilization of H. verticillata to benefit the agriculture field. This paper provides a summary of growth, harvest and recent development for the management and use of H. verticillata. Based on the present scenario, possible forthcomings are discussed.

Different heating processes were applied to pretreat the pulp and paper mill sludge to enhance the hydrolysis stage. Hot air oven, autoclave, microwave and water bath were used for comparison. Chemical analyses exposed that all the pretreatment methods have shown improvement in solubilisation of organic matter. Among the pretreatments studied, heat transfer through hot air (80 °C for 90 min) mode had the highest impact on sludge solubilisation. There was an increase in cellulose (P = 0.0096), acid soluble (P = 0.0053) and insoluble lignin (P = 0.0012), but decrease in hemicellulose (P = 0.0009) content after pretreatment. The XRD and FT-IR spectroscopic characterisation shows the development of aliphatic, unsaturated and carbonyl carbon functionalities in the pretreated samples at higher severities. FESEM picture also confirms the change in structure after pretreatment. Thus, pretreatments contribute to disruption of the lignocellulosic structure making the cellulose easily accessible to acidogenic microorganisms.

The pollution of surface water has become a global environmental issue. Monitoring of surface water is essential to know the current status of water quality and maintain it at certain desirable level. In this study surface water quality of Amingaon has been analysed. Amingaon is a locality in North Guwahati (Assam, India). In last few decades’ the locality has undergone rapid and uncontrolled development activities which have a detrimental impact on its ecology and environment. Samples were collected from 12 lakes and analysed for 24 parameters namely temperature (T), pH, electrical conductivity (EC), turbidity (Tur), total suspended solids (TSS) and total dissolved solids (TDS), total alkalinity (TA), total hardness (TH), chloride ion (Cl−), fluoride (F−), sulphate (SO42−), sodium (Na+), potassium (K+), calcium (Ca2+), dissolved oxygen (DO) biochemical oxygen demand (BOD), chemical oxygen demand (COD), ammonium nitrogen (NH3-N), total Kjeldahl nitrogen (TKN), nitrate (NO3−) total phosphorus (TP) and available phosphorus (AP). Multivariate statistical techniques were used for the assessment of water quality. Cluster analysis (CA) was used for classification of water quality parameters and principal component analysis (PCA) was used to identify the sources of pollution. CA grouped all the water quality parameters in three cluster. PCA resulted in six useful components which explained 90.54% of the total variance. Based on overall study it was concluded that the sources of pollution of lakes were the use of fertilizers, storm water runoff, land development and domestic waste water discharge. Trophic state of lakes was also evaluated using Carlson's Trophic State Index (TSI).

As a potential pathway to sustainable construction, this novel study demonstrates the feasibility of incorporating degraded municipal solid waste (MSW) as one of the constituents for production of fired bricks. The raw materials, degraded MSW and two different soils, i.e. laterite soil and alluvial soil, were mixed together in different proportions ranging from 5 to 20%. Specimens of these mixtures were then fired at 850 and 900 °C respectively. Various properties such as bulk density, linear shrinkage, loss on ignition, water absorption, compressive strength, and modulus of elasticity on light of the respective Indian and ASTM standard codes were studied and compared. An optimum constituent mix of 20% degraded MSW with (laterite or alluvial) soil fired at temperature of 900 °C was found to be most appropriate for brick production. The ultimate uptake of this study is 8% net saving in the energy consumption of external fuel by mixing 20% degraded MSW.

Highlights • Management of terrestrial weeds is one of the key concerns in world wide. • These noxious weeds participate with crops with their natural resources. • Terrestrial weeds can be managed by anaerobic digestion and vermicomposting. • Most of these weeds contain high lignin. • Pretreatment is required to further recovery of energy., The management of terrestrial weed is of great concern for the scientific community as these weeds cause adverse effect in different ecosystems like forest, agriculture and urban. The widespread of these weeds by their adaptive capability and morphological advancement is difficult to control. Parthenium hysterophorous, Lantana camara, Saccharum spontaneum, Ageratum conyzoides are the weeds that spread all over the world. There are various management practices employed for the control of this weeds. But all of these practices have some drawbacks those are neither environment friendly nor economical. In this paper a review has been done to evaluate various alternative management practices for these terrestrial weeds and to analyze their feasibility. Vermicomposting and anaerobic digestion can be viable alternative option which is cost effective as well. There are few studies regarding vermicomposting and anaerobic digestions of terrestrial weeds are done.

The study aimed to characterize the microbial population involved in lignocellulose degradation during drum composting of mixed organic waste i.e. vegetable waste, cattle manure, saw dust and dry leaves in a 550 L rotary drum composter. Lignocellulose degradation by different microbial populations was correlated by comparing results from four trials, i.e., Trial 1 (5:4), Trial 2 (6:3), Trial 3 (7:2) and Trial 4 (8:1) of varying waste combinations during 20 days of composting period. Due to proper combination of waste materials and agitation in drum composter, a maximum of 66.5 and 61.4 °C was achieved in Trial 1 and 2 by observing a temperature level of 55 °C for 4–6 d. The study revealed that combinations of waste materials had a major effect on the microbial degradation of waste material and quality of final compost due to its physical properties. However, Trial 1 was observed to have longer thermophilic phase leading to higher degradation of lignocellulosic fractions. Furthermore, Fourier transform infrared spectrometer and fluorescent spectroscopy confirmed the decrease in aliphatic to aromatic ratio and increase in polyphenolic compounds of the compost. Heterotrophic bacteria were observed predominantly due to the readily available organic matter during the initial period of composting. However, fungi and actinomycetes were active in the degradation of lignocellulosic fractions.

This paper reports the results of an exploratory experimental study to manufacture eco-friendly lightweight bricks through binary mix of paper mill sludge (PMS) and soil. The pre-manufacture activities include mineralogical, chemical, thermal and index properties characterisation of two kinds of soils (laterite and alluvial) and PMS. The mix ratio between PMS and soil was varied (0%, 5%, 10%, 15% and 20%) and two firing temperatures 850 °C and 900 °C were tested in order to emulate the typical conditions of a kiln. The performance of incorporating PMS into the mix was tested by evaluating properties such as linear shrinkage, compressive strength, water absorption, mass loss on ignition, and bulk density of bricks as recommended by the relevant Indian and ASTM standard codes. X ray diffraction results confirmed that the addition of PMS does not show any phase transformation and only enhances the porosity thereby leading to weight reduction. Based on the results, an optimum mix of 10% PMS with both soil types was found suitable for brick production at a firing temperature of 900 °C. Results obtained in this study will be helpful to brick industry for commercial production of PMS incorporated bricks leading to sustainable use of resources.

Utilization of different types of solid wastes through composting is important for environmental sustainability and restoring soil quality. Although drum composting is an efficient technology, the possibility of heavy metal contamination restricts its large-scale use. In this research, a field experiment was conducted to evaluate the impact of water hyacinth drum compost (DC) and traditional vermicompost (VC) on soil quality and crop growth in an agro-ecosystem cultivated intensively with tomato and cabbage as test crops. A substantial improvement in soil health was observed with respect to nutrient availability, physical stability, and microbial diversity due to the application of drum compost and traditional vermicompost. Moreover, soil organic carbon was enriched through increased humic and fulvic acid carbon. Interestingly, heavy metal contamination was less significant in vermicompost-treated soils than in those receiving the other treatments. The use of VC and DC in combination with recommended chemical fertilization effectively stimulated crop growth, yield, product quality, and storage longevity for both tomato and cabbage.

The methane production rate increases with a decrease in moisture content up to the optimum threshold level and diminish in a batch reactor fed with the lignocellulosic material in solid state anaerobic digestion. The interpretation on two-faceted effect of moisture content could not be elucidated by the conventional anaerobic digestion model no 1. This study proposed that the decreased moisture content causes augmented mass diffusion resistance by the accumulation of hydrolytic product. This could lead to the reduced production of methane gas. Based on the hypothesis, a new solid state anaerobic digestion model was developed based on mass diffusion limitation and hydrolysis inhibition. The better degree of agreement between model simulation and the literature as well as experimental data verified that the deterioration in the volumetric rate of methane production. This could be attributed to hydrolysis inhibition as a result of limited mass diffusion in solid state anaerobic digestion.

Purpose The present work aims to isolate and identify bacterial community from the rotary drum compost of green waste such as the water hyacinth. Compost quality was also investigated with the physicochemical parameters and the heavy metal analysis. Methods For rotary drum composting, a waste mixture of 150 kg with water hyacinth, cow dung and sawdust were prepared in the proportion of 6:3:1, respectively. The physicochemical parameters such as pH, temperature, volatile solids and the electrical conductivity were analyzed to detect the compost quality. Pb, Ni, Zn, and Cd were investigated for total heavy metals, toxicity characteristic leaching procedure (TCLP), diethylenetriaminepentaacetic acid (DTPA) and water solubility tests. Consistent and active bacterial community were isolated from the rotary drum compost of water hyacinth. Culture-dependent and culture-independent techniques were approached for the isolation process. Results Twelve bacteria were isolated and identified by 16S rDNA sequencing and phylogenetic analysis; they majorly belonged to the Bacillus and Enterobacter family. The analysis of temperature, pH, EC, VS and heavy metals depicted the good quality of compost. Heavy metals concentration was in Pb > Ni > Zn > Cd; however, for Pb, Cd and Ni water solubility remained non-detectable, DTPA concentration for Pb and Cd was also found to be non-detectable. Conclusions The microbes in water hyacinth compost are metabolically active degrading the organic matter, surviving in the heavy metal-loaded compost environment. Thus, green waste (water hyacinth) can be utilized to isolate bacterial species in anticipation of their application in heavy metal removal in liquid and solid waste sources for micro-bioremediation.

This study investigates the use of electrohydrolysis pretreatment on water hyacinth to cut short the hydrolysis step and increase biogas production at the same time. Electrohydrolysis pretreatment of water hyacinth at 20V for 60min exhibited improved solubilisation (42.9%). Therefore, bio-chemical methane potential (BMP) test was carried out between water hyacinth pretreated at 20V for 60min and untreated water hyacinth. By the end of 30days, cumulative methane production of 2455±17mL CH4/g VS for electrohydrolysis pretreated substrate and 1936±27mL CH4/g VS for the untreated substrate was achieved. Compositional analysis and characterization study revealed the efficiency of electrohydrolysis pretreatment in melting the lignin and lowering the cellulose crystallinity of water hyacinth.

This novel work is focused on evaluating the electrohydrolysis pretreatment conditions (applied voltage and time) and anaerobic digestion process for the biological bioconversion of pulp and paper mill sludge into biogas in batch assay. The pretreatment at 15 V for 45 min shows highest impact on sludge solubilization. The XRD and FT-IR spectroscopic characterization shows the development of aliphatic, unsaturated and carbonyl carbon functionalities in the pretreated samples. FESEM picture also qualities the change in alteration of structure after pretreatment. Batch anaerobic bioreactor was carried out to determine the efficacy of electrohydrolysis pretreated and untreated pulp and paper mill sludge. The methane production potential was increased from 274 ± 5 to 301 ± 4 mL CH4/g VS after electrohydrolysis pretreatment.

Effects of waste carbide sludge (CS) on microbial diversity and degradation of lignocellulosic fractions of mixed agricultural waste was experimented using a 550 L rotary drum composter. Four different trials of varying carbide sludge i.e. trial 1 (0%), trial 2 (1%), trial 3 (2%) and trial 4 (3%) was carried out for the study. The drum was turned every 24 h once to provide proper aeration and mixing of the waste materials for higher degradation and availability of organic matter to the microbial population. Hence with proper combination of waste materials and optimum addition of CS, a maximum of 31.56% reduction in Acid insoluble lignin (AIL), 46.03% of hemicellulose (HC) and 47.54% of cellulose (C) was observed in trial 2. The appropriate addition of CS was considered to increase the overall microbial activity of the composting process in trial 2. However, higher addition of CS in trial 3 and 4 was not effective in terms of higher degradation of volatile solids and also led to loss of organic nitrogen. In addition, it also increased the pH of compost to alkaline conditions and had a major effect on the growth of fungi. Pathogens i.e., Salmonella , Shigella was completely eliminated at the end of 20 days due to higher temperature and addition of waste carbide sludge in trial 2, 3 and 4 at the end of 20 days.

Heavy metal content has become a serious issue with increase in compost application in agricultural land. The bioavailable fraction (water soluble and diethylene triamine pentaacetic acid (DTPA) extractable) is the major concern comparing to the total concentration as it can be taken up by plants which in turn affects the human health. Thus, this study was carried out to determine the variation in bioavailable and leachable fraction of heavy metals (Cd, Cu, Fe, Ni, Pb, Cr, Zn, Hg and Mn) and to assess the influence of temperature, pH, organic matter degradation and humification during rotary drum composting of paper mill sludge (PMS) for 20 days. A total concentration of all the metals as well as nutrients increased during composting. The Hg was not detected in water soluble and DTPA extractable fraction, whereas Pb and Cr were also not detected in water soluble fraction in all the trials. A decreasing trend was observed in leachable quantity for all the metals during composting. Water extractable quantity increased for Fe and Cu during composting. Organic matter degradation and humification during composting influences the variation in bioavailability and leachability of heavy metals, which can be optimized by applying appropriate proportion of cow dung during rotary drum composting of PMS.

In landfills, properties of the liner become affected due to the presence of harmful chemicals that, in turn, reduce its efficiency. In this study, two bentonites having different chemical ...

The present study evaluates biodegradation of the polyblends of poly(lactic acid) (PLA), polycaprolactone (PCL) and microcrystalline cellulose (MCC) in different compositions and comparison of the properties of those blends with that of neat PLA and neat PCL. The samples were melt extruded and blended to evaluate the environmental fate of the polyblends under simulated composting conditions following the standard ASTM International D5338-15 protocol. It was seen that blends with a higher concentration of PCL and MCC in the PLA matrix showed higher carbon mineralization percentage in comparison to the blends having low PCL and MCC components. Molecular weight analysis of the samples showed a decrease in their weight due to chain scission mechanism leading to the formation of intermediates. Analytical techniques revealed the formation of microbial biofilms on the blended biopolymeric surfaces. Field emission scanning electron microscopy showed the formation of fibril-like structures by PLA, and the formation of rough patches on the PCL surface re-confirmed biodegradation of the samples. This work fuels interest in the material characterization of PLA/PCL/MCC based polyblends and helps in tuning the biodegradability of the studied samples according to the demands.

Compost is generally used for soil conditioning, growing plants and remediation of pollution. It is imperative to evaluate compost standard and toxicity test is a salient parameter for determining compost quality. Seed germination test is an essential method to discern the phytotoxicity of compost. Ecotoxicity of water hyacinth compost was inspected for the denouement of the compost quintessence and its concentration on seed germination indices. The aim of this paper was to assess seed emergence rate index, germination velocity coefficient and rate of germination of L. esculentum and B. oleracea at discrete concentrations of water hyacinth compost. The highest germination percentage achieved was 95% (L. esculentum) at 100 g/L and 100% (B. oleracea) at 32 g/L of the compost extract. The probability of inadvertent ceasing of germination was found to be 0.0001 for either of the test species. Consequently, the water hyacinth compost aid plant growth and is recommended for substantially ameliorating languishing ecological idiosyncrasy.

High moisture content in organic wastes leads to a leachate production. Vegetable waste is one kind of municipal solid organic wastes holding very high moisture (88–94%) and thus becoming nuisance to the environment. Composting is a viable technology to treat such organic waste. This research mainly deals with the insight on physic state of composting during composting of vegetable wastes added with the inoculum and bulking agents. This study showed the attainment of thermophilic stage (65–70 °C) during the composting process and completed with the pathogen-free end product. The bulk density increased from 312 to 380 kg m− 3 and was well within the recommended range (less than 1000 kg m− 3). The electrical conductivity of the end product was also within the mentioned range (

This study reports the biodegradation behaviour of polylactic acid (PLA) based biocomposites under three different types of compost. In order to check its biodegradability under natural outdoor soil condition another study was designed comprising of PLA and compared with polycaprolactone (PCL) based biocomposites and polyblends containing fillers like wood-dust, algal biomass and microcrystalline cellulose (MCC). Under thermophilic composting conditions, it was found that neat PLA samples took around 95-110 days to degrade. For outdoor (uncontrolled) degradation, natural soil available was selected for the test and samples were buried 20 cm deep. After bioplastic biodegradation under composting condition the final biomass formed was used to evaluate its ecotoxicological impact on crop (Solanum tuberosum L) growth following OECD 2006 test guidelines. This study revealed current understanding to spot the data gaps and future analysis priorities related to final biomass of bioplastic biodegradation as well as biopolymer's tremendous role in “nature-to-nature” sustainability.

The present study was aimed to evaluate the pollution load and toxicity of petroleum refinery wastewater (PRW) before and after the biological treatment process. PRW induced phytotoxicity and cyto-genotoxicity in mung bean (Vigna radiata L.) and onion (Allium cepa L.) were investigated. The physico-chemical analysis such as pH, BOD, COD, EC, solids, total phenol, and other pollutants in PRW sample were high and beyond the permissible limits. The GC–MS and FTIR analysis suggest the presence of toxic organic pollutants. In comparison to control, the seeds of V. radiata exposed to 100% PRW sample showed a reduction in seed germination, root length, shoot length, and biomass by 50%, 85.1%, 69.3% and 36.6%, respectively, after 5 days of treatment. A. cepa root exposed to different concentration of wastewater samples indicated the reduction of root length and biomass in concentration dependent manner when compared to untreated solutions, after 5 days of incubation. A. cepa root tip rooted in different concentration (25%–100% v/v) of PRW samples showed a significant reduction in mitotic index (MI%) from 67.7 % to 38.7% compared to control root tip cells (79.3%) exposed to tap water indicating the induction of the cytotoxicity. Besides, wastewater induced genotoxicity as evidenced by the presence of various chromosomal aberrations (CAs) and nuclear abnormalities (NAs) in A. cepa root tip cells. However, after the secondary treatment process, the toxicity of the PRW was reduced compared to untreated. Thus, the present study’s finding reported that PRW generated different types of toxic organic and inorganic pollutants and may act as phytotoxic and cyto-genotoxic agents.