Plant Waste Materials Research Articles

Structural Properties of Bacterial Cellulose Film Obtained on a Substrate Containing Sweet Potato Waste

The paper presents the results of research on the microstructure of bacterial cellulose (BC-SP) obtained on a medium containing sweet potato peel, which was compared to cellulose obtained on a synthetic medium containing sucrose and peptone (BC-N). The properties of cellulose were analyzed using the methods: size exclusion chromatography (SEC), X-ray diffraction (XRD), scanning electron microscope (SEM), and computer microtomograph (X-ray micro-CT). BC-SP was characterized by a higher degree of polymerization (5680) and a lower porosity (1.45%) than BC-N (4879, 3.27%). These properties give great opportunities to cellulose for various applications, e.g., the production of paper or pulp. At the same time, for BC-SP, a low value of relative crystallinity was found, which is an important feature from the point of view of the mechanical properties of the polymer. Nevertheless, these studies are important and constitute an important source of knowledge on the possibility of using cheap waste plant materials as potential microbiological substrates for the cultivation of cellulose-synthesizing micro-organisms with specific properties.

Removal of lead and chromium from solution by organic peels: effect of particle size and bio-adsorbent

A variety of organic wastes can be used in innovative methods to treat water pollution through the adsorption process. In this work, we evaluated the effect of particle size (500–2000, 250–500, and less than 250 μm) and bio-adsorbent (orange, potato, and passion fruit peels) on the removal of lead and chromium from solution. The size and type of peels affected the capacity to adsorb metal ions (p < 0.05). Passion fruit peel had the highest metal adsorption, followed by orange and potato, since the cation exchange capacity (217.70 ± 39.57 cmol (+) kg−1) and the specific surface area (141.10–1095.29 cm2 g−1) were higher in the passion fruit rind. The size of the adsorbent did not affect the organic matter, ash, exchange capacity, surface chemistry, or pH of the peels. However, these properties differed among the bio-adsorbents (p < 0.05). The Freundlich equation explained the adsorption of the metallic ions on the orange rind and of lead on the passion fruit. The linear model was the best fit for the adsorption isotherms of the metals on potato peel. The adsorption of chromium on the passion fruit had a maximum adsorption capacity of 3.3 mg g−1. These results indicate that plant waste materials, especially passion fruit peel, have the potential as feasible and low-cost adsorbents in pilot studies for the treatment of polluted water.

PEMANFAATAN SAMPAH ORGANIK DAN TANAMAN LOKAL MENJADI ECO-ENZYME BAGI MASYARAKAT DESA LUMBAN PEA TIMUR BALIGE

Community Service (PkM) is carried out by the Faculty of Agriculture, Universitas Methodist Indonesia by providing organic farming counseling and training on the manufacture of eco-enzymes from vegetable, fruit and local plant waste for the community, especially farmers. PkM was held on June 9, 2022 in Lumban Pea Timur Village, Balige District, Toba Regency, North Sumatera Province. The method used is to conduct organic farming counseling as well as training to make eco-enzymes by utilizing waste materials from vegetables, fruits and local plants. This is a solution to the problems and constraints faced by farmers in the form of decreasing soil quality due to the use of inorganic fertilizers. At the time of providing counseling, it was explained that there was a decrease in soil quality due to the application of inorganic fertilizers that had been carried out in the long term. Likewise, the explanation of efforts to fix and improve soil quality through the provision of eco-enzymes. The results of PkM with organic farming counseling are very effective considering that there are still many farming communities who do not understand that it is necessary to improve and maintain soil quality by using eco-enzymes. With the existence of organic farming counseling as well as the manufacture of eco-enzymes, the farming community becomes aware of efforts to improve the soil and what benefits can be obtained by making eco-enzymes. Thus, it is hoped that the Lumban Pea Timur farmer community will always be motivated to improve and maintain soil quality independently by utilizing vegetable, fruit and local plant waste materials.

Cucumber (Cucumis sativus L.) Leaf Extract as a Green Corrosion Inhibitor for Carbon Steel in Acidic Solution: Electrochemical, Functional and Molecular Analysis.

An extract of cucumber leaves (ECSL) was prepared as a green corrosion inhibitor for carbon steel. Its carbon steel corrosion inhibition performance against 0.5 mol L−1 H2SO4 was investigated using electrochemical methods and scanning electron microscopy (SEM). Its composition was analyzed by gas chromatography and mass spectroscopy (GC−MS). Quantum chemical calculations and molecular dynamics simulations (MDS) were conducted to elucidate the adsorption mechanism of the inhibitor molecules on the carbon steel surface. The results indicated that the inhibition efficiency increases with its increasing concentration. The extract acted as a mixed type corrosion inhibitor, and its inhibition properties were ascribed to the geometric coverage effect induced by its adsorption on the metal surface in accordance with Langmuir’s law. The active components in the extract were identified as mainly organic compounds with functional groups such as aromatic moieties and heteroatoms. The inhibition activities of ECSL are delivered through the ability of the active components to adsorb on the metal surface through their functional groups to form a protective layer which hinders the contact of aggressive substances with carbon steel and thus suppresses its corrosion. This research provides an important reference for the design of green corrosion inhibitors based on plant waste materials.

Production and bromatological analysis of the oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P.Kumm.) grown with cocoa, banana, coconut and African palm husk substrates

Oyster mushroom (Pleurotus ostreatus (Jacq. ex Fr.) P.Kumm. (1871) is a rich food source. It is cultivated on compost and plant waste material. Choosing adequate substrate is essential for oyster production as the substrate can change oyster production in terms of mass and metabolite composition. The different medium substrates for oyster production including T1 (PDA, potato-dextrose-agar), T2 (CCA: PDA + Cocoa Shell), T3 (APR: PDA + African Palm Rachis), T4 (BP: PDA + Banana Peel), T5 (CCO: PDA + Coconut Peel) were used. Based on mycelial diameter, CCO treatment was the best treatment with growth measures of 66.83 mm at 168 hours. CCA treatment with 164.13 g kg-1 yield had the highest production that was significantly different from other treatments. For APR treatment, trace production was observed. The bromatological analysis determined that the highest levels of crude total protein were obtained in CCO treatment (30.08 %) while CCA treatment exceeded significantly dry matter (94.05 %), ethereal extract (6.52 %), crude fiber (12.34 %), non-nitrogen matter (56.15 %) and titratable acidity (3.32 %). The substrates with more lignocellulosic compounds like banana and coconut residues are better for producing oyster with a higher percentage of total protein, while substrates that retain moisture like cocoa residues lead to an excellent production. It is recommended to keep fibrous residues moist constantly when they are used in oyster production because of their low absorbent capacity as they quickly lose moisture.

Flower Bulb Waste Material is a Natural Niche for the Sexual Cycle in Aspergillus fumigatus.

With population genetic evidence of recombination ongoing in the natural Aspergillus fumigatus population and a sexual cycle demonstrated in the laboratory the question remained what the natural niche for A. fumigatus sex is. Composting plant-waste material is a known substrate of A. fumigatus to thrive and withstand temperatures even up to 70°C. Previous studies have shown indirect evidence for sexual reproduction in these heaps but never directly demonstrated the sexual structures due to technical limitations. Here, we show that flower bulb waste material from stockpiles undergoing composting can provide the conditions for sexual reproduction. Direct detection of ascospore structures was shown in agricultural flower bulb waste material by using a grid-based detection assay. Furthermore, we demonstrate that ascospores can germinate after exposure to 70°C for up to several days in contrast to asexual conidia that are unable to survive a two-hour heat shock. This indicates a sufficient time frame for ascospores to survive and escape composting stockpiles. Finally, sexual crosses with cleistothecium and viable ascospore formation could successfully be performed on flower bulb waste material. Recombination of A. fumigatus can now be explained by active sexual reproduction in nature as we show in this study that flower bulb waste material provides an environmental niche for sex.

Evaluation of Local Pour Point Depressant on Waxy Crude Oil

Pour point of crude oil has been a huge concern in flow assurance at some stage in crude oil production and transportation. Pour point depressants are used as chemical additives when transporting crude oils at temperatures below their pour point to prevent the fluid not to flow. Various chemical additives which are synthetic products are quite expensive for usage. This study utilizes oil extracted from plant waste material such orange peel (OP) and soya bean husk (SBH) as pour point depressants for Nigerian waxy crude oil. Effects of plant extracts on pour point of the two crude oil samples A and B were investigated using pour point apparatus. The waxy crude oil sample without pour point depressant, waxy crude oil sample doped with soya bean husk oil (SBHO), waxy crude oils sample doped with orange peel oil (OPO) and waxy crude oil sample doped with toluene gave pour point values of 86°F, 75.5°F, 64.48°F and 75.5°F then and 80.6°F, 75.2°F, 59°F and 80.6°F at 2800 ppm for waxy crude oil samples A and B respectively. The results obtained revealed that the oils extracted from these agricultural waste product could depress the pour points of the crude oil appreciably while orange peel oil (OPO) exhibited highest depression ability, however OPO which performed better than soya bean husk oil (SBHO) and Toluene and OPO could be a good substitute for pour point depressants for waxy crude oil.

Inhibition of ammonia and hydrogen sulphide as faecal sludge odour control in dry sanitation toilet facilities using plant waste materials

On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilets as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two dry sanitation facilities named T1 and T2. The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed that the odour levels for H2S in both T1 (3.17 ppm) and T2 (0.22 ppm) were above the threshold limit of 0.05 ppm, for unpleasantness in humans and vice versa for NH3 odour levels (T1 = 6.88 ppm; T2 = 3.16 ppm; threshold limit = 30 ppm limit). The biomasses exhibited low pH (acidic = 5–7) whereas the biochars and ashes had higher pHs (basic = 8–13). Basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%) than acidic biocovers. The effect of pH on suppression of NH3 was determined to be statistically insignificant at 95% confidence limit. In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that biochar produced from locally available waste plant-based materials, like sawdust, can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.

Comparing rheological, tribological and sensory properties of microfibrillated cellulose dispersions and xanthan gum solutions

Utilisation of plant waste materials contributes to sustainable food production and allows preparation of functional ingredients from natural bio-materials. Microfibrillated cellulose (MFC) from plant waste materials such as citrus peels has been suggested to have potential as “clean label” thickener. This study compared rheological (shear and extensional rheology, hysteresis, yield stress), tribological and sensory properties of MFC dispersions (0.2–2.0 wt%) to xanthan gum (XG) solutions (0.04–4.3 wt%) and linked sensory characteristics to instrumental properties. Concentrations of MFC and XG were chosen so that shear viscosities of MFC dispersions and XG solutions were similar over a large range of shear rates. XG had higher extensional viscosity at high deformation rates than MFC. XG had higher yield stress than MFC at similar shear viscosity. Yield stress increased linearly with increasing concentrations for XG, while it increased exponentially for MFC. Seventy-three consumers evaluated the appearance, flavour, and mouthfeel of all samples using the Rate-All-That-Apply (RATA) method. Sensory differences between MFC and XG were generally larger at higher concentrations. MFC dispersions were less transparent and had more intense cardboard flavour than XG solutions of comparable shear viscosity. At high thickener concentrations, XG solutions were perceived as glossier, stickier, slimier and more mouthcoating than MFC dispersions of similar shear viscosity. Sticky, slimy and mouthcoating perception were correlated with extensional viscosity at higher deformation rates. We conclude that MFC can thicken foods similar to XG while avoiding undesired texture sensations such as mouthcoating, sliminess and stickiness. The flavour and dispersibility of MFC need to be improved further before it can be applied as thickener in foods.

Dynamics of Phloridzin and Related Compounds in Four Cultivars of Apple Trees during the Vegetation Period

Apple trees (Malus domestica Borgh) are a rich source of dihydrochalcones, phenolic acids and flavonoids. Considering the increasing demand for these phytochemicals with health-benefitting properties, the objective of this study was to evaluate the profile of the main bioactive compounds—phloridzin, phloretin, chlorogenic acid and rutin—in apple tree bark, leaves, flower buds and twigs. The variety in the phenolic profiles of four apple tree cultivars was monitored during the vegetation period from March to September using chromatography analysis. Phloridzin, the major glycoside of interest, reached the highest values in the bark of all the tested cultivars in May (up to 91.7 ± 4.4 mg g−1 of the dried weight (DW), cv. ‘Opal’). In the leaves, the highest levels of phloridzin were found in cv. ‘Opal’ in May (82.5 ± 22.0 mg g−1 of DW); in twigs, the highest levels were found in cv. ‘Rozela’ in September (52.4 ± 12.1 mg g−1 of DW). In the flower buds, the content of phloridzin was similar to that in the twigs. Aglycone phloretin was found only in the leaves in relatively low concentrations (max. value 2.8 ± 1.4 mg g−1 of DW). The highest values of rutin were found in the leaves of all the tested cultivars (10.5 ± 2.9 mg g−1 of DW, cv. ‘Opal’ in September); the concentrations in the bark and twigs were much lower. The highest content of chlorogenic acid was found in flower buds (3.3 ± 1.0 mg g−1 of DW, cv. ‘Rozela’). Whole apple fruits harvested in September were rich in chlorogenic acid and phloridzin. The statistical evaluation by Scheffe’s test confirmed the significant difference of cv. ‘Rozela’ from the other tested cultivars. In conclusion, apple tree bark, twigs, and leaves were found to be important renewable resources of bioactive phenolics, especially phloridzin and rutin. The simple availability of waste plant material can therefore be used as a rich source of phenolic compounds for cosmetics, nutraceuticals, and food supplement preparation.

The Production of Biodegradable Flowerpot from Sludge of Rubber Factory with Waste from Mushroom Culture and Palm Bunches

The concept for this research is that plants pots are produced from rubber plant sludge and waste material from the mushroom lump and palm bunch are use to replace products that are made from plastic, which is an alternative to reduce the amount of waste and add value to the waste material. The aims for this work are 1) to study the chemical characteristics of raw materials 2) to study the physical characteristics, and 3) to study properties of plant pots produced from rubber plant sludge, waste material from the mushroom lump and palm bunch. The conditions of experiment are 6 ratios between rubber plant sludge to waste material from the mushroom lump including 0 : 100, 20 : 80, 40 : 60, 60 : 40, 80 : 20 and 100 : 0. using wet glue and palm bunch as binder and subsidiary binder, respectively. The results revealed that 1) raw material has acid-base, conductivity, and moisture value suitable for growing plants, 2) the first ratio had the highest average weight of 246.67 grams and plant pot could be molded well, strong and have smooth skin, and 3) the first ratio has qualifications suitable for actual application; the water absorption was 99.18 percentages, an inflation value was 81.93 percentages and the slowest deterioration of the plant pot.

Dynamics of Aspergillus fumigatus in Azole Fungicide-Containing Plant Waste in the Netherlands (2016-2017).

The treatment of patients suffering from Aspergillus diseases is hampered due to infections with Aspergillus fumigatus that are already resistant to medical azoles. Previous work has suggested that A. fumigatus likely gains resistance through environmental azole exposure in so-called hot spots. Here, we investigated A. fumigatus resistance dynamics over time at three sites at which farmers used azole fungicides for crop protection. Over 16 months, 114 samples were taken from stockpiles of decaying plant waste. A. fumigatus and azole fungicide residues were ubiquitously present in the plant waste. On average, 105A. fumigatus CFU/g was recovered, of which roughly half were itraconazole and tebuconazole resistant. Similar tandem repeat-mediated resistance mechanisms were found in colonies cultured from plant waste as reported in clinical azole-resistant isolates. Our results show a consistent high burden of azole-resistant A. fumigatus in azole-containing plant waste and underscores the need to further investigate resistance-reducing interventions and transmission routes.IMPORTANCEAspergillus fumigatus is consistently present independently on season at a high abundance in plant waste material throughout the sampling period. Our study confirmed that long-term storage sites of azole-containing decaying plant material can indeed be considered hot spots, which can sustain resistance development and maintenance in A. fumigatus Roughly half of individual isolates were azole resistant and carried genetic mutations that are highly similar to those found in patients with azole-resistant invasive aspergillosis. Our work suggests that environmental sources of azole resistance in A. fumigatus may be important, underscoring the need for further studies on environment-to-patient transmission routes.

Suppressiveness of Soil Amendments with Pelleted Plant Materials on the Root-knot Nematode Meloidogyne Incognita.

SummarySoil treatments with formulated plant biomasses or waste materials can be an effective alternative to green manure crops for a sustainable management of root-knot nematode infestations. The suppressive performance of soil amendments with three commercial formulations of defatted seed meal from Brassica carinata, dry biomass of Medicago sativa and pressed pulp from Beta vulgaris was comparatively evaluated on the root knot nematode Meloidogyne incognita both on potted and field tomato (cv. Regina) trials. Products were applied at rates of 10, 20, 30 or 40 g/kg and 20 and 40 T/ ha soil in pots and field, respectively. Soil non treated or treated with the nematicide Oxamyl were used as controls in both experiments. Amendments in potted soil significantly reduced M. incognita infestation on tomato roots compared to both the untreated control and treatment with Oxamyl, also increasing tomato plant growth up to the 30 g/kg soil rate. At the end of the field tomato crop, soil population density of M. incognita resulted significantly reduced by all the tested treatments, whereas tomato yield was significantly higher than the untreated control only at the lowest amendment rate. Soil amendments with the materials tested in this study demonstrated to be a potential additional tool for a satisfactory and safe management of root-knot nematodes.

Green and cost-effective synthesis of copper nanoparticles by extracts of non-edible and waste plant materials from Vaccinium species: Characterization and antimicrobial activity

The aim of this work was the green synthesis of copper nanoparticles (Cu-NPs) using aqueous extracts of (i) bilberry (Vaccinium myrtillus L.) waste residues from the production of fruit juices and (ii) non-edible “false bilberry” fruits (Vaccinium uliginosum L. subsp. gaultherioides). Different cupric salts (CuCl2, Cu(CH3COO)2 and Cu(NO3)2) were used for the synthesis. The formation of stable nanoparticles (CuNPs) was assessed by transmission electron microscopy and the oxidation state of copper in these aggregates was followed by X-ray photoelectron spectroscopy. The polyphenol composition of the extracts was characterized, before and after the synthesis, using spectrophotometric methods (i.e. total soluble polyphenols and total monomeric anthocyanins) and high-performance liquid chromatography coupled with tandem mass spectrometry (i.e. individual anthocyanins). Polyphenol concentration in the extracts was found to decrease after the synthesis, indicating their active participation to the processes, which led to the formation of Cu-NPs. The antimicrobial activity of Cu-NPs, berry extracts, and cupric ion solutions were analysed by broth microdilution and time-kill assays, on prokaryotic and eukaryotic models. The antimicrobial activity of Cu-NPs, especially those derived from bilberry waste residues, appeared to be higher for both Gram-negative and Gram-positive bacteria, and for fungi, compared to the ones of its single components (cupric salts and berry extracts). Therefore, Cu-NPs from the green synthesis here proposed can be considered as a cost-effective sanitization tool with a wide spectrum of action.

Valorisation of Ribes nigrum L. Pomace, an Agri-Food By-Product to Design a New Cosmetic Active

The ethical and ecological concerns of today’s consumers looking for both sustainable and efficient ingredients in finished products, put a lot of pressure on the cosmetic market actors who are being driven to profoundly modify the strategies adopted to innovate in terms of actives while notably being urged to switch from petroleum- to plant-based ingredients. To produce such natural cosmetic ingredients, agri-food by-products are advocated as raw material due to their reduced carbon footprint as they actively contribute to the worldwide improvement of waste management. The process to transform plant waste materials into such powerful and objectified “green” cosmetic actives in compliance with circular economy principles is a long-term integrated process. Such a development is thoroughly exemplified in the present paper through the description of the design of liquid anti-age ingredients based on Ribes nigrum L. extract. This was obtained by maceration of blackcurrant pomace. and the embodiment of this extract following its phytochemical analysis notably by HPLC-DAD-ELSD and its bioguided fractionation using in vitro bioassays.

Indigenous waste plant materials: An easy and cost-effective approach for the removal of heavy metals from water

The waste plant materials, including neem wood, eucalyptus, pine cone wood, almond shell, walnut shell and sawdust, were used as biosorbents to remove heavy metals from the water. The % removal efficiency of each biosorbent for copper (Cu), zinc (Zn), manganese (Mn), lead (Pb), chromium (Cr) and arsenic (As) was estimated at various pH and for different contact hours by using atomic absorption spectrometer. All biosorbents have shown poor efficiencies for arsenic removal, while their % removal efficiencies towards other metals were found appropriate at near drinking water pH (7.5) and at a contact time of 3 ​h. Among all biosorbents, pine cone, eucalyptus and neem wood have shown comparatively more significant removal of Cu, Zn, Mn, Pb and Cr. The overall % removal efficiencies were found greater with pine cone wood and the value reached to 99% for Cu removal. For arsenic removal, the sawdust was modified by chemical treatment and significant removal up to 80% was found.

Procena maksimalne proizvodnje biogasa iz različitih sirovina - eksperimentalna studija

This study reveals the maximum biogas production capacity of different biomass using plant and animal waste material as feedstock. A comparative experiment conducted under anaerobic condition showed that biogas yield from poultry litter (28 liters) was higher than that of rice husk (18 liters) in a 30day retention time. However, the yield of biogas was significantly influenced by the composition of the waste feedstock and the environmental conditions within the reactor. The poultry litter had already undergone some digestion process before it was excreted by the birds, which means their bonds were broken by digestive organisms which made the anaerobic digestion process to be easily accomplished. Similarly, the rice husk had a low gas production rate due to the presence of high lignin properties because rice is a lignin cellulose material. Therefore, for optimum gas production, the waste should be pretreated at lower temperate region to increase the digestion temperature since temperature exerts a major influence in biogas production.

Effective Utilization of Banana Plant Waste Materials for Catalytic Converter Filter in Kirloskar Diesel Engine

There is always a demand to develop better filter materials for the increasing pollution problems. This work deals with the study on the effect of activated carbon particles deposited on the honeycomb filter of catalytic converter for better adsorption of emission gases. In this work, naturally available banana plant materials were utilized to synthesize activated carbon. This was deposited in the form of coating on the honeycomb filter material. The effectiveness of adsorption of gases like NOx, CO and HC was analyzed using Atlon gas analyzer

The Effect of Different Compost Compositions on Arbuscular Mycorrhizal Colonization and Nutrients Concentration of Leek (allium Porrum L.) Plant

ABSTRACTPlant residue material produced compost is an organic fertilizer source and it is commonly used for soil amendments. Also in order to reduce the amount of chemical fertilizers need mycorrhizal inoculation can be used as an agricultural strategy. Thus, the aim of the research is to examine the effect of several residue materials produced compost and mycorrhizae fungi with two growth media on leek plant growth, nutrient uptake, and mycorrhizae spores’ production.Eight different row organic materials and animal manures were used as compost production during 8 months. Leek (Allium porrum L.) plants were inoculated with Funneliformis mosseae and Claroideoglomus etunicatum with a level of 1000-spore per pot. The leek plant was analyzed for determination of nutrient concentration, root colonization, spore production, and shoot/root dry weight.The composts were made from domestic waste, animal manure (bovine animal), animal manure (ovine animal), and different plant materials were determined to be the most suitable compost material for plant growth and mycorrhizal spore production compared to the rest of compost material. Mycorrhizal inoculation significantly increased leek plant growth and nutrient uptake especially phosphorus (P), potassium (K), copper (Cu) and zinc (Zn). Plants grown in 5:3:2 (volume/volume) growth media was responded better to the mycorrhizal inoculation than grown in 1:1:1 (v/v) growth media. Funneliformis mosseae inoculated plants have higher plant growth and nutrient uptake than that of Claroideoglomus etunicatum inoculation.

Conceptual modifications of coal preparation plants to minimize potential environmental issues associated with coal waste disposal

An environmental concern at coal preparation operations is the release of elements resulting from the oxidation or dissolution of certain minerals contained in the process waste streams. Using a standard conductivity test, the electrical conductivity (EC) of water samples obtained from mixing with various particle size and density fractions of a given plant waste material were measured as an indicator of total dissolved solids. The net neutralization potential (NNP) of the fractions were also measured to predict the pH of the supernatant upon disposal. As a result, the particle size and density fractions contributing to high EC levels were identified with the objective of potentially extracting and isolating these fractions which can significantly reduce the negative environmental impacts. The results showed that the EC generated from coarse refuse streams were significantly higher than the values obtained from fine refuse streams. Based on the NNP values, the coarse refuse stream generates highly acidic pH, while the fine refuse in contact with water produces circumneutral pH. Furthermore, the high specific gravity (>2.68) fractions which comprised less than 10% of the coal waste streams were found to be the primary source of elevated EC levels. The remaining fractions were found to be of minimal environmental concern. Based on the obtained results, modifications to the coal preparation plants were proposed to minimize the environmental concerns of coal waste disposal. Modifications include pyrite removal from the spiral refuse and desulfurization of flotation feed and sieve bend underflow streams using low-cost mineral spiral circuitry. After the segregation, the pyrite (high density) fraction, which encompasses around 1% of the coarse and fine refuse streams, will be isolated/encapsulated and the fine refuse stream dewatered and co-disposed with the coarse refuse stream. The proposed modifications to the processing and disposal practices not only minimize the generation of acid mine drainage thereby reducing the release of trace elements and EC of the discharged water, but also enhances the recovery and quality of the final clean coal product.