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Being a relatively rare mineral, Tamarugite has good coagulation properties. Tamarugite's utilization for coagulation applications has been a great initiative towards the appreciation of this mineral. Aluminium dross, hazardous industrial waste material has been used to produce Tamarugite. The aluminium content present in the dross has been leached into the sulphuric acid. The addition of sodium hydroxide solution into the leached liquor provides for the sodium ions essential for the Tamarugite stoichiometry. It has been found after characterizing the product that the precipitation of Tamarugite by organic solvent furnishes a purer form of Tamarugite. Also, compared to the Tamarugite produced by crystallization, the Tamarugite formed by organic solvent precipitation shows enhanced coagulation performance. To study the reusability of organic solvents for precipitation, ethanol has recycled for the repeated production of Tamarugite. It is observed that the quality of the resultant Tamarugite is maintained. Linking the aspects of industrial waste management and recycling of aluminium dross to water treatment plants, the present article presents a deeper insight into the science behind the synthesis and application of Tamarugite. A holistic view of the article illustrates the alternative method of recycling aluminium dross and enhancement of Tamarugite's applicability in coagulation. The article contributes to environmental management in broadly two ways: industrial waste management and water treatment by coagulation.

A cleaner production of one-part alkali activated cement (AAC) was implemented by mixing chemically treated concrete waste (CTC) with slag. The treatment process was conducted by the addition of NaOH to concrete waste (CoW) at NaOH to CoW weight ratios of 0.2, 0.1, and 0.05 (namely, CTC-1. CTC-2, and CTC-3, respectively), followed by mixing with water and drying. The solidified material was ground then dry-mixed with slag to create one-part alkali AAC powder with fixed particle size. The amount of CTC was varied to achieve constant Na2O content (2 wt %) in all mixtures. The results indicated that the prepared one-part AACs can react with water to yield hardened materials with acceptable compressive strength. Comparing with CTC-1 and CTC-3, the CTC-2 was found to have a dominant impact on the activation of slag hydration, which associated with the higher mechanical properties, lower pore volume, and drying shrinkage. The addition of lead bearing sludge (LBS) to one-part AAC containing CTC-2 resulted in a positive impact on the performance of the prepared cement. According to toxicity characteristic leaching procedures the prepared cement showed a potential effect on solidification/stabilization of Pb-containing-sludge.

The palm oil industry has been one of the major economic contributors for Malaysia over the last decade. While contributing to the country's economic growth, the industry has inevitably produced a significant amount of waste materials which are harmful to the environment. Oil palm boiler ashes (OPBA) generated from boiler in mills are disposed in open landfills which are easily carried away by the wind. The disposed ash pollutes the air while spent earth, when left in landfills, produce a pungent odour. The present work investigated the possibility of refining palm oil with raw OPBA and pelletized OPBA as alternate bleaching adsorbents. The performance of different types OPBA (raw, enhanced and pelletized) was investigated to determine their bleaching efficiencies on carotenoid removal at various operating conditions. Crude palm oil samples were refined with these OPBA and compared with commercial bleaching earth to investigate the final refined oil colours. A final refined oil colour of 4.0R was obtained using 0.05 wt% of enhanced OPBA when bleached at 110 °C for 45 min under constant agitation (300 rpm) and subsequently deodorized at 265 °C for 1 h. This study has indicated that the use of enhanced OPBA which could achieve more than high removal of carotenoid could substitute commercial bleaching earths to produce a comparable final refined oil colour rating. The successful substitution of OPBA to replace the conventional bleaching earth in oil refining could significantly reduce the production cost. This is also a sustainable solution for the edible oil processing industries to mitigate the solid waste and contributes to a cleaner environment.

In the last decades the media have highlighted the ozone depletion as major environmental problem resulting in an increase in ultraviolet radiation (UVR) reaching the earth's surface. Besides the beneficial effects of human exposure to UVR, this radiation is capable of causing damage to human population. The healthy lifestyle is becoming widely accepted by the public, and the UV protection provided by clothing becomes the significant subject of interest of the producers and consumers of textile fabrics. Natural cellulose fibres are commonly used in summer clothing due to their excellent comfort properties. However, these fibres have very poor UV protection ability. In this project, the UV protection property of textile fabrics made of natural and regenerated cellulose fibres have been compared and analysed in order to highlight the potential of hemp fibre for the development of more sustainable and healthy functionalized (UV protective) textile products. A group of homogeneous and blended cellulose textile fabrics were manufactured in a knitwear factory, evaluated in terms of the structure, and spectrophotometrically assessed to indicate their UV protection ability. The knitted fabrics merited sun protection ratings of “good” for pure hemp, through “very good” for viscose containing fabrics to ”excellent” UV protection category for cotton based fabrics. Relatively high values of the Ultraviolet Protection Factor (UPF) of the cellulose materials resulted from the interaction of fibre type, yarn geometry, fabric properties and common processing techniques. The increased UVR transparency of the pure hemp fabric, which resulted from hemp elasticity limitations, overcame by blending with other softer and more elastic cellulose fibres (cotton, viscose). The engineering approach proposed in this study was confirmed as an effective way to create more sustainable (more sustainable resource, pollution prevention, energy and cost savings) textile products with high level of UV protection at the knitting production stage avoiding the use of any additional mechanical and chemical treatments. These results revealed that the future application of hemp fibres in textile products with high added-value are promising. A co-ordinated effort of different subjects of the agro- and textile-industry production chain need to continue so as to overcome the limitations associated with hemp production and fibres properties.

The objective of this work was to study the valorization of residual biomass and wastewater from acai fruit processing to obtain energy products and higher added value from such residues, through the integration between subcritical waterpretreatment and anaerobic digestion technologies. Subcritical watertechnology was performed to pretreat the residual biomass. For this process, the reactorwas feed with 5 g of acai residue and a solvent to biomass mass ratio of 80 g of water per gram of acai residue was used. The process was carried out at 170 and 200 °C, during 20 min, using water flow of 20 mL min−1 (15 Mpa system). Then, the residual biomass was submitted to the anaerobic digestion process using a reactor with pretreatment (integration) and a control reactor, both in semi-continuous regime and under mesophilic conditions (35 °C). The acai stone had a high carbohydrate concentration including 43.81% cellulose and 25.89% hemicellulose. For the evaluated conditions, subcritical water pretreatment at 200 °C gave the bestresultsforyield of reducing sugars, total reducing sugars and monosaccharide concentration. Anaerobic digestion experiments resulted in analkalinity between 150 and 1537 mgCaCO3.L−1 for the control reactor and between 249 and 491 mgCaCO3.L−1 for the reactor integration.Acetic acid was the main volatile fatty acid produced in both reactors, but butyric acid also had a very high concentration in the control reactor. The methane composition in the biogas for the integration reactor in the stabilization phase was between 60 and 80%, whilefor the control reactor it was in the range between 40 and 60%.The accumulated biogas yield was 7.79 and 791.81 L.KgTVS−1 for the control and integration reactor, respectively. Anaerobic digestion using the acai hydrolysate obtained by subcritical water pretreatment showed a significant advantage over the control digestion, resulting in30% more methane in the biogas and 100 times higheryield.

Systematic investigation of the effects of hydraulic retention time and substrate concentration on biohydrogen production rates in pilot-scale fermenter is of great academic and practical interests. The present study applied a 3 m3 pilot-scale bioreactor that composed of three sequential 1 m3 chambers (#1-#3) to investigate the effects of hydraulic retention time and substrate concentration on biohydrogen production rates from glucose. The 48 h hydraulic retention time resulted in poor mixing of the medium; chamber #1, which received the feed substrate, converted too much glucose, and little glucose was left to be utilized in the following chambers. However, a 12 h hydraulic retention time allowed insufficient volatile fatty acids to be produced, so a reductive environment for biohydrogen production was difficult to establish. At the optimal hydraulic retention time, 24 h for the present fermenter, sufficient mixedness of the medium and fermentation times for all chambers maximized the biohydrogen production rates. Biohydrogen production rates were increased as the substrate concentration was increased from 10 to 30 g/L, peaked at 100.16 mol/m3-d, and then decreased with the increase in substrate concentration. Unique in the literature, the reported data reveal the effects of substrate concentration on biohydrogen production rates in pilot-scale fermenter, guiding to the design and development of the pilot-scale bioreactors with high hydrogen yields that could help to improve the industrialization development of biohydrogen production.

The reuse and recycling of water in an industry is a hot topic in today's growing economy; considering water scarcity, strict regulations for discharge and the high cost of water treatment and supply. This study was planned to investigate the treatment and recycling potential of textile wastewater using membrane technology. Several combinations of ultrafiltration (UF) and nanofiltration (NF) membranes were applied both independently and in sequential arrangements to find the most suitable option for each type of segregated wastewater flow. However, dyeing and first washing wastewater with high salinity, the configuration of UP005 + NF200 + NF90 in a sequential arrangement provided 99.4% color, 99.1% COD, and 43.2% conductivity rejection. The UF + NF configuration was evaluated as the most promising solution to achieve the required water quality for water reuse applications without affecting fabric dyeing parameters and quality in case of pre-treatment and post dyeing operations.

The present study has enabled to establish an appropriate kinetic and operational condition for hydrogen production using ultrasonicated palm oil mill effluent (POME). The kinetic analysis was performed corresponds to cumulative hydrogen (H2) production by varying substrate-inoculum ratio (COD/VS) from 0.2 to 0.6. The maximum H2 production potential (P) of 448 mL H2 with lag-time (ρ) of 8.2 h and H2 production rate (Rm) of 14.62 mL H2 h−1 was achieved using the substrate-inoculum ratio of 0.6. However, the Rm of 17.979 mL H2 h−1 with the ρ of 16.84 h, which is almost double than the substrate-inoculum ratio of 0.6 was observed at a substrate-inoculum ratio of 0.4. Furthermore, response surface methodology (RSM), including experimental design, regression analysis, was successfully applied to achieved optimum substrate-inoculum ratio and initial pH for biological H2 production from ultrasonicated POME. The maximum yield of 0.416 L H2/g-CODremoval was observed at the optimum conditions of substrate-inoculum ratio of 0.5 and an initial pH of 5.0. The linear, quadratic and interactive effect of substrate-inoculum ratio and initial pH on H2 yield were significant.

Effective valorization of nutrient rich wastes for the fertilizer application is a promising method towards sustainable development. Nutrient rich wastes were mainly researched for production of biochar straight (single nutrient) fertilizer through slow pyrolysis. Appropriate waste feedstocks and cleaner thermal processing need to be explored for value addition. In present study, potassium (K) containing banana peduncle and phosphorus (P) rich effluent sludge (chemical fertilizer industry) wastes co-utilized for development of biochar complex fertilizer. Different thermal treatments viz slow pyrolysis (700 °C) and thermal plasma processing (1200–1500 °C) were trialed for production of biochars with desired characteristics. Plasma processing produced biochar with higher total P (8.53 – 11.81 %) and K (17.13 – 21.9 %) than slow pyrolysis (P-4.2 % and K-11.5 %). In contrast, slow pyrolysis resulted higher biochar yield (42 %) and total carbon content (34.1 %) than in plasma (28 – 34 % and 10.9 – 21.8 %). Bio-available phosphorus of effluent sludge (600 mg/kg) enhanced to 4500 – 6000 and 5600 mg/kg in plasma and slow pyrolysis biochars. XRD analysis indicates the presence of P as hydroxyapatite in sludge and biochars. The K was dominantly present as kalicinite (KHCO3) in slow pyrolysis and fairchildite [K2 Ca (CO3)2] specifically in plasma biochar. Biochars contained lesser total (0.18 –1.55 %) and leachable (0.014 – 0.034 %) fluoride than effluent sludge i.e. 3.45 and 0.076 %. These results demonstrate utilization potential of aforementioned wastes and thermal processes for the production of K and P enriched biochar complex fertilizer. Its application will be suitable for non-food crops and degraded soil reclamation due to toxic constituents.

Waste penicillin bottles, a main component of medical wastes, have greatly produced in the world. Because of containing residual medicines and different microorganism, this kind of medical wastes is considered as hazardous waste. The unidentified microorganism inside waste penicillin bottles makes it difficult to dispose and manage. To our knowledge, there was little published information about the suitable recovery technology of waste penicillin bottles. In this study, the microorganisms in penicillin bottles were identified by the methods of gram staining and gene sequencing. Two gram-positive bacteria in the penicillin bottles were found, one was gram-negative bacterium, the other was fungus. The results of the analysis of gene sequencing and phylogenetic trees of the four bacterial showed three injurious microorganisms (Cladosporium australiense, Staphylococcus haemolyticu, and Vagococcus carniphilus) were presented in waste penicillin bottles. We also developed a novel process to recover nano glass from waste penicillin bottles. It included the processes of shearing, screen, and ball-milling. When the ball-milling time was greater than 36 h, most of the glass particles had the size ranged in 200–400 nm, 400–600 nm, and 600–800 nm, even reached the size of 0–200 nm. Ball-milling of the glass of waste penicillin bottles will bring a certain economic benefits by selling this nano glass. Additionally, we also found the transient temperature on glass particles during ball-milling process could reach 476 °C, which was enough to kill the injurious microorganisms. Therefore, ball-milling can reduce the cost of sterilization of medical wastes. This study provided a new and safe technology of recovering nano glass from penicillin bottles of medical wastes.

In this study, the removal of zinc from plating wastewaters using fixed bed columns packed with hydrolyzed olive cake was investigated. This work discusses the significance of the scale-up and provides a brief overview of the potential uses of exhausted biosorbent for the generation of zinc-based materials. First, biosorption studies were performed to analyze biosorption behavior of hydrolyzed olive cake in different sized columns. Influence of important design parameters such as contact time, linear velocity and bed height/diameter ratio on biosorption performance was studied. Results indicated a significant effect of contact time on scale-up. Higher bed depths increased the biosorption capacity due to a larger dose of absorbent in the packed columns. As the flow rate increased, the breakthrough time decreased and the exhaustion of the column was reached faster. In addition, operating at the same contact time and bed height/diameter ratio and at a linear velocity much higher in the pilot column, the zinc uptake capacity was found to be higher. Better biosorption results could be due to velocity influencing the mass transfer and hydraulics improving the fluid dispersion. Finally, exhausted biosorbent was subjected to different thermal treatments. Preliminary tests showed that zinc-loaded solid can be recycled for the generation of zinc-based materials.

Recycling schemes from rare-earth-containing scraps have been developed rapidly due to the increasing supply risk for rare-earth elements (REEs). This article aimed to reduce the ecological impact and reagent costs for separating and recycling REEs from scraps, i.e., spent ceria-based polishing powders and lutetium-based crystal waste. A simultaneous process was proposed using an industrial extractant Cyanex®572, which allowed efficient recycling of REEs from the wastes with less acid and alkali consumption than traditional hydrometallurgy process. Based on thermodynamic and kinetic analyses, common acid scrubbing was avoided by employing REEs scrubbing. Additionally, the alkali saponification, acid stripping and oxalic acid precipitation were substituted by one step of precipitation-stripping-saponification with ammonium fluoride which contained abundant F− in the solution with weak acidity. F− was easy to complex with REEs on the extractant as precipitate while NH4+ bonded with anion of the extractant. Using this technique, the vast consumption of chemicals and million tons of wastewater in REEs industry may be avoided. Totally, the chemical consumption could be reduced over 80% and the wastewater was decreased more than 90%. REEs recovery yield also increased considerably using the novel process. Moreover, the ammonium fluoride was designed in containment system and was reused with no emission to the environment. This article provides a sustainable and efficient alternative process to REEs waste treatment industry.

Techno-economic models for three plants in Queensland, Australia using thermochemical conversion of 10 tonnes per hour of sugarcane bagasse to liquid crude biofuels were developed. Thermochemical conversion was chosen to maximise yield from second-generation feedstock. The process models highlighted the differences in mass and energy flows of each process. Factory models were generated reflecting current methods in heat and material recovery. Liquefaction generated the highest amount of product per kg feed, followed by pyrolysis and gasification. Key parameters affecting plant economics were also highlighted. Based on net present values, the profitability was ranked as follows: pyrolysis > liquefaction > gasification. The plants were all sensitive to product price, thermochemical conversion ratio and refining conversion ratio, thereby affecting profitability the most. Conversion ratios sharply affect the minimum selling price of products, but attenuated by high product volumes. Varying tax rates and capital costs do not affect the minimum selling price as much as conversion ratios, therefore, incentives around improving conversion rates and increasing product volume are recommended.

The combustion is an effective way of sewage sludge treatment and provides an attractive source of energy. However, the heavy metals (HMs) volatilization and the energy demand are restrictive factors for sewage sludge combustion. This study focused on the heavy metals fixation with the sorbents addition and the energy balance of sludge combustion using the bench scale and pilot tests. The proximate and the combustion characteristic analysis showed that the volatile component burning played a dominant role during the combustion of the sludge, but the reaction mechanisms for their combustion steps were different. Bench-scale tests indicated that with 6.25% kaolin addition, temperature of 900 °C, and residence time of 20 min, the fixation ratios of Cu, Pb, Ni, Cd, Cr, and Zn were reached 94.60%, 90.69%, 93.75%, 90.71%, 92.21%, and 96.53%, respectively. Long-term pilot tests demonstrated that the energy consumption for the combustion of one ton dehydrated sludge could be as low as 62 kW h with a 10-m long electric heating rotary kiln. Furthermore, the escaped Pb, Cd, Cr, Cu, Ni, and Mn were only 2.12 g, 0.12 g, 0.86 g, 33.90 g, 1.61 g, and 66.67 g, respectively, per ton dried sludge. This study can provide an environmentally friendly and economical way of treating sludge.

The use of abundant natural wastes as environmentally friendly products promotes a circular green economy and cleaner production. The potential use of natural waste materials without additional processing for the removal of priority pharmaceuticals from water was investigated. Here, the performance of selected low-cost biosorbents (biochar, macro-algae and wood chippings) was evaluated using two extensively prescribed model pharmaceuticals: diclofenac (DCF) and trimethoprim (TMP). The physicochemical properties of the biosorbents were examined (to shed light on likely biosorption mechanisms) using Brunauer–Emmett–Teller (BET) measurements, scanning electron microscopy (SEM), zero point of charge (pHzpc) measurements and Fourier transform infrared spectroscopy (FTIR). Experimental data from kinetic studies fitted a pseudo-second order model, and multiple diffusion steps limited the mass transfer of analytes. Intra-partile diffusion was the rate limiting step for biochar, while macro-algae and wood chippings were limited (mainly) by adsorptive attachment. The equilibrium data for most of the studied systems best fitted a Langmuir model, while the Freundlich model provided a better fit for TMP with wood chippings. At μg∙L−1 initial pharmaceutical loading levels, the maximum biosorption capacity for DCF was attained with biochar (7.25 × 103 μg g−1), while macro-algae performed best for TMP (7.14 × 104 μg g−1). Both chemical and physical interactions were likely responsible for the biosorption of pharmaceuticals. High removal efficiencies were achieved at the low initial loadings studied, indicating the potential application of those sustainable low-cost biosorbents at low (environmentally relevant) pharmaceutical concentrations.

The conventional transesterification process employed in biodiesel production from vegetable oils is not only a time-consuming process but operated under raised temperatures. A novel liquid-phase plasma discharge process was developed and evaluated in this study. The process could continuously convert soybean oil to biodiesel under room temperature at a much faster rate than the conventional method. Two feeding flowrates (2.7 ml s−1 and 4.1 ml s−1) were used in the experiments. Methanol to oil molar ratio, Rmomr, and NaOH to oil weight ratio, RNaOWR, were each examined at five levels (3, 4, 5, 6, and 7 for Rmomr, and 0.4, 0.6, 0.8, 1.0, and 1.2 wt% for RNaOWR). Central Composite Design and Response Surface Methodology to optimize the conversion rate and applied voltage was conducted. At the flowrate of 2.7 ml s−1, the optimal values of Rmomr, RNaOWR, conversion rate, and applied voltage were 5.08, 0.79 wt%, 97.2%, and 1.17 kV, respectively. While at 4.1 ml s−1, these values became 5.18, 0.70 wt%, 99.74%, and 1.27 kV. All regression models generated by the Central Composite Design and Response Surface Methodology fitted the experimental data well. The biodiesel produced by the novel liquid-phase plasma discharge process met the industrial quality standards (ASTM Standards).

Biogas internal combustion (IC) engines of less than 1 MW are either equipped with an oxidative catalyst or operate at low-emission operation parameters to meet national emission standards of NOx, CO, VOCs, HCl, H2S, SO2, and formaldehyde safely. However, expensive oxidative catalysts have a limited lifetime of less than two years, and electrical efficiency at low-emission conditions is lower than that at optimal conditions, characterized by higher emission levels. While NOx levels increased seven times from 282.2 to 1965.7 mg NOx∙m−3 by changing the operational parameters of the four-stroke gas engine (Pel = 360 kW), emission levels of CO and VOC slightly changed from 540.3 to 452.5 mg CO∙m−3 and 509.6 to 329.9 mg C∙m−3. Furthermore, NOx emission levels could be reduced by a minor air to gas ratio, but levels of VOC, CO, and HCl increased at these conditions as shown for a four-stroke gas engine (Pel = 635 kW). The emissions of the dual-fuel gas compression-ignition engine (Pel = 265 kW) were generally characterized by higher emission levels. A chemical scrubber with an optional subsequent biofilter was installed as a low-cost alternative for oxidative catalysts as a waste gas treatment system. Corresponding performance levels of the chemical scrubber were in the range of 28.3–38.6% (NOx), 19.2–30.8% (CO), 22.6–23.8% (VOCs), and 33.3–70% (odor). Formaldehyde, which occurred at levels of 43.4–59.6 mg m−3, was almost completely eliminated by the scrubber after injection of ambient air, but the system failed in tests without air injection. The performance was further enhanced by addition of H2O2. Further approaches in chemical removal of formaldehyde by addition of NH3 or urea failed. The biofilter showed no treatment performance under thermophilic conditions. The amortization time of the scrubber system was less than three years, caused by economic benefits of higher electrical efficiency and substitution of the catalyst.

Recently, the conversion of palm waste to activated carbon for various applications has attracted significant attention from researchers. Over the years, abundant palm wastes have been generated due to active palm milling in various part of the world. These environmentally challenging wastes have been converted to valuable and economical materials for gas adsorption and water treatment but rarely for energy storage application. The lignocellulose composition of palm wastes has made it a favorable candidate for starting material of activated carbon for supercapacitor application. In this review, the pretreatment condition, factors to consider for choosing starting material, activation techniques, and activation parameters such as activation temperature, activation time, activation agent and impregnation ratio are analyzed. The advantages of the synergistic effect of the lignocellulose composition of different palm wastes for energy storage device is discussed. The major drawbacks in the conventional Barrett-Joiner-Halenda (BJH) porosity characterization technique are addressed and the novel Non-localized Density Functional Theory characterization technique is suggested. Conclusively, future prospects in the activation of palm bio-wastes for supercapacitor application are highlighted.

Flue gas desulphurization process in coal-fired power plants, produces wastewater with concentrated sulfate, chloride, metals and refractory organic compounds, which leads to serious pollution and corrosion problem during recycling. In this study, an integrated process of chemical precipitation and sulfate reduction for treatment of coal-fired power plant flue gas desulphurization wastewater was developed. Without additional of heavy metal trapping and strong oxidizing agents, chemical precipitation was performed as pre-treatment for removal of suspended solid (97%) in raw flue gas desulphurization wastewater. Comparison study on treatment of pre-treated flue gas desulphurization wastewater were performed in three parallelly operated sequencing batch reactors, by cultured sulfate reducing bacteria strain BY7, SR10 and SR3, respectively. This study demonstrated that strain BY7 and SR10 sulfate reducing bacteria were able to adapted to high-salinity flue gas desulphurization wastewater, with high efficiencies of sulfate reduction (86–94%), metals (70–100%) and refractory organic compounds removal (85–95%). The highest sulfate loading rate of 0.5 kg SO42−/m3·d was achieved in sequencing batch reactors with strain BY7 and SR10. Besides, a sustainable removal of chloride and fluoride were achieved (about 35% and 55%, respectively), which probably relate to co-precipitation or biosorption processes. Up to 14 out of 25 refractory organic compounds in flue gas desulphurization wastewater could be completely removed after integrated treatment process. As response to flue gas desulphurization wastewater stress, abundance of monounsaturated fatty acids were increased, and upregulated expression of genes related to salt detoxification were observed in SBR_BY7 and SBR_SR10. Therefore, this study provided a potential low-cost flue gas desulphurization wastewater recycling technology with simultaneously removal of sulfate, refractory organic compounds, heavy metal and salts.

The current methods used for the production of activated carbon (AC) are often chemical and energy intensive and produce significant amount of chemical waste. Thus, clean production of AC is important to reduce its overall production cost and to limit the adverse effect on the environment. Therefore, the main aim of this study is to develop a clean method for AC production from woody biomass with low chemical consumption. Herein, this study reports a facile strategy for reducing chemical usages in the production of high-performance AC, by introducing a crucial pre-pyrolysis step before chemical activation of biomass. The ACs prepared were characterised using scanning electron microscopy, Fourier transform infrared spectroscopy, nitrogen and carbon dioxide gas adsorption measurements. All these characterisations indicated that produced ACs have similar physicochemical properties. The strategy reduced chemical use by 70% and produced high-performance ultra-microporous ACs with excellent carbon dioxide adsorption capacity (4.22–5.44 mmol m−2). The facile pre-pyrolysis method is recommended for further research as a cleaner activated carbon preparation method from biomass feedstock.

Fly ash of some thermal power plants is rejected when their chemical compositions do not satisfy the limit values in related standards and consequentially conveyed to landfills. In this study, a rejected fly ash, which has high sulphite, free lime, and magnesium oxide contents and does not comply with the classification standards of fly ashes, having cementing properties, has been examined. This rejected fly ash is moistened with water in the thermal power plant and then transported to landfills. This humidified fly ash that has been in contact with snow and rain for a long time turns to hydrated fly ash. The analysis of this hydrated fly ash showed that the sulphite, free lime, and magnesium oxide content levels of the hydrated fly ash had decreased compared to the original rejected fly ash. After the hydrated fly ash in the landfill was ground and sieved, self-compacting mortars (SCMs) were produced by replacing PC with 10, 20, and 30% hydrated fly ash. At various pH levels, leaching of Ca2+ in SCMs was investigated. Hydrated fly ash is found to be excellent powder material to increase the leaching resistance of Ca2+ in an SCM when used to replace PC with 20% hydrated fly ash.

To achieve salt-free and low-alkaline reactive cotton dyeing, ethanol-water mixture with high concentration of ethanol in volume was employed as medium for cotton fabrics dyeing by reactive dyes. The influence of ethanol concentration and wet pickup of pre-swollen cotton fabric on both water and ethanol contents in the fabric, dye exhaustion and fixation rates were investigated, and the effect of ethanol concentration and alkali dosage on the alkali content in pre-swollen cotton fibers were also investigated. The dyeing properties in ethanol-water system was also compared with that in conventional aqueous system. The results indicated that both ethanol concentration and wet pickup were important factors influencing water and ethanol contents of pre-swollen cotton fabrics and ultimately dye exhaustion and fixation. The percentage of alkali on the fabric in ethanol-water system was much higher than that in conventional aqueous system, and can be controlled by the ethanol concentration and the alkali dosage. It also can be concluded that the optimum condition was pre-swollen cotton fabrics with 40% wet pickup dyed in ethanol-water system with 80 vol% of ethanol. The dyed sample under the optimum condition had higher K/S value and levelness than the water-dyed sample, and its dry and wet rubbing fastnesses were found similar or acceptable in comparison with the water-dyed sample. More importantly, no electrolytes had been used in our ethanol-water system and the alkali dosage was one fifth of that in conventional aqueous system, contributing to the environmental benefits of ethanol-water system.

Wastewater from olaquindox-producing factories contains high levels of salts and organics. In this study, we investigated the multiple freeze-thaw technology to recover olaquindox from wastewater and decrease its chemical oxygen demand (COD) and salinity. Results suggested that under lower ice formation rate, the removal efficiencies of COD, electric conductivity, ammonia nitrogen and total nitrogen could reach 99.4%, 98.2%, 98.7% and 98.5% respectively. Higher ice formation rate, however, promoted wastewater concentration and volume reduction. A liter of wastewater concentrate can recover 11.5 g solid through a simple crystallization step at 4 °C for 12 h. This substance contained mostly olaquindox based on Raman infrared spectroscopy, scanning electron microscopy, and energy dispersive spectrometry. An industrial-scale wastewater treatment process, which the theoretical cost is one seventh that of conventional technologies, was then proposed to recover olaquindox and treat wastewater.

Use of recirculating aquaculture systems (RAS) to grow fish is on the rise. Fish feed typically contains 25–60% protein and is the only significant input in RAS. Fish recover 20–30% of the applied feed as biomass, and the unassimilated nitrogen is released into the water, mainly as ammonia, which is toxic to fish. Nitrification is the most common treatment practice, converting ammonia to the less toxic nitrate, and nitrogen removal is achieved by either water exchange or denitrification. The aim of this study was to develop and test a novel approach to remove nitrogen based on a microaerophilic assimilation side-reactor. In the suggested system, fish solid waste and dissolved nitrogen are assimilated into protein-rich microbial biomass, which has the potential to partially offset fish feed input. Initially, a theoretical model based on the system’s nitrogen mass balance was established. Then, an intensive pilot-scale RAS was constructed, growing ∼50 kg fish/m3. The system consisted of a fish tank, solids filter, and microaerophilic assimilation reactor based on activated sludge treatment. Intrinsic solid waste and wheat-flour waste were used as carbon source. After a trial run of about 2.5 months, the RAS was tested for 101 days. Average total ammonia nitrogen, nitrite, and nitrate removal were 89.1, 69.4 and 100%, respectively. Of the introduced solids, over 82% were lost as carbon dioxide by respiration, 11.7% were recovered as microbial biomass and 6.5% as fish biomass, and only 0.6% remained in the water. Biomass organic content was similar to aquafeed and nitrogen content was equivalent to 40% crude protein. Daily energy demand for the system’s designed capacity of 80 kg/m3 would result in a low energy consumption of 7.72 kW h/kg fish. Overall, a novel concept for sustainable production in intensive aquaculture was developed and successfully demonstrated in a pilot-scale RAS.

In this study, the feasibility of using sludge as a flue gas denitration agent for the cement industry was evaluated, and factors affecting NOX (NO + NO2) removal were systematically investigated using a custom-built laboratory-scale fluid-bed reactor. The results indicate that sludge is an effective NOX reducing agent, and sludge dosage, combustion temperature, and O2 concentration greatly affect NOX removal. Finally, the optimal operation conditions for the sludge denitration process were determined. With a sludge dosage of 0.75 g/min, sludge particle size of 60–80 mesh, combustion temperature of 900 °C, gas flow rate of 18 L/min, O2 concentration of 3% (v/v), and the CO2 concentration of 25% (v/v), the maximum NOX removal efficiency could reach 74.16 ± 4.65%. Moreover, preliminary research on the mechanism showed the occurrence of homogeneous and heterogeneous NOX reductions during the sludge denitration process. The homogeneous NOX reduction considerably contributes to NOX removal. Therefore, the use of sewage sludge as a flue gas denitration agent for the cement industry is feasible.

Untreated agricultural waste results in significant environmental pollution and reduces economic efficiency in The Three Gorges Reservoir Region. Ensiling is a method used to improve biowaste-to-resource systems and enhance the efficiency of resource recycling. Nutrient-rich citrus waste are suitable raw material for ensiling in China, but unsuitable for large-scale ensiling. In this study, citrus waste and other agricultural by-products were used to ensile as livestock feed in a family-scale silo. Spatial variation in microbiome composition and silage quality was analyzed in the bunker silo. From the top to the bottom of the silo, the crude protein, crude fiber, and pectin contents all increased, while the loss rate of dry matter decreased, indicating that the silage quality was better in the lower section of the silo. Spatial variation in temperature, pH, and moisture significantly influenced silage quality by influencing the composition of the microbiome. Undesirable Enterobacteriaceae and Trichocomaceae were replaced by Lactobacillus, Saccharomycetaceae, Sphingobium, and Pediococcus during ensiling. Proteolysis was mainly due to the decomposition of crude protein and further hydrolysis of soluble protein by Sphingobium, Brevundimonas, and fungi. Crude fiber and pectin were primarily degraded by unclassified_o_Saccharomycetales and norank_o_Eurotiales. The pH of the silage decreased from the top to the bottom of the silo as well from the outside to the center, which is attributed to the presence of Lactobacillus and Pediococcus. More homofermentative lactic acid bacteria should be added to raw materials that are positioned higher in the bunker silo to improve silage quality. The reuse of agricultural waste as silage in Changshou Agricultural Park of the Three Gorges Reservoir Region could result in increase in annual profits of $8,282.50 USD; however, the waste handling expenses totaled $8,416.00 USD. The application of this BTR method will reduce the shortage of fermented feed and result in significant economic benefits.

This study explored the production of biogas from the mono-fermentation of pretreated Cocoa pod husk. The pretreatment was carried out with sulfuric acid (H2SO4) and alkaline hydrogen peroxide (H2O2) prepared by adjusting the pH of H2O2 to 11.5 by the addition of 5 M NaOH solution. Prior to and after the pretreatments, physicochemical, structural and microbial analyses were carried on the husk using a standard method in each case. In order to determine the changes to the biomass structures after pretreatments, the Fourier Transform Infra-red (FTIR) spectroscopy were used. Average total biogas volume from all the experiments i.e. the acidic pretreated (AcP), alkaline pretreated (AlP), not sifted untreated (NsU) and sifted untreated (SU) was 162.8 ± 5.0, 564.8 ± 5.1, 243.3 ± 4.1 and 220.8 ± 3.3 respectively. This shows that the AlP Cocoa pod husk yielded the highest biogas volume and was followed by the NsU and the SU husk while the lowest was obtained from the AcP biomass. Overall, the AlP biomass produced 71% more total biogas than the AcP one and also produced 57% more biogas than the NsU Cocoa pod husk. The AlP Cocoa pod husk did not only produce the highest biogas volume but also achieved peak of production faster than all the other experimental setups. Total biogas generation was achieved in just 12 days out of the 30-day retention period used in the study in which biogas production started on the 3rd day and climaxed on the 15th experimental day whereas, biogas generation did not commence until after the 5th and 6th days in other experiments and climax was not reached until between the 18th and 21st days. The result of this study has revealed that use of the low cost mild alkali is more efficient in lignin (L) solubilization and subsequent biogas yield improvement. Also, Cocoa pod husk has been shown in this study to be a profound biofuel substrate. Therefore, further use of AlP Cocoa pod husk for biogas and biofertilizer production is hereby advocated especially in major Cocoa producing regions of the world.

Microplastic pollution has become emerging environmental concern around world. The wastewater treatment plants (WWTPs) are attributed to a major pathway for microplastics (MPs) to enter into aquatic environment. To understand the fate and control strategies of MPs in WWTPs, we investigated MPs at a full-scale WWTP, Eastern China, with two parallel wastewater treatment systems, i.e. oxidation ditch (OD) and membrane bioreactor (MBR) for case study. The influent MPs consisted of polyethylene terephthalate (PET, 47%), polystyrene (PS, 20%), polyethylene (PE, 18%) and polypropylene (PP, 15%). MP morphotypes dominated in fragments (65%) and fibers (21%), which mainly were PET, with limited films (12%) and foams (2%). Typical plastic microbeads were not observed. The dominant size of MPs was >500 μm (40%) and 62.5–125 μm (29%). MP concentrations increased across the treatment systems depends on facility of treatment process. Influent MPs were removed by 99.5% in MBR system versus 97% in OD system on the basis of plastic mass while 82.1% versus 53.6% on MP number. The removed MPs accumulated in sludge phase. MBR system has much higher MP removal efficiency than OD system, likely due to membrane filtration. The results suggest that the source control of MPs by eliminating MP fibers from laundry facilities, banning use of plastic microbeads, Styrofoam products and plastic bags and properly selecting WWTP treatment unit could significantly reduce the mass and number of MPs from WWTPs.

Some commercial products of anion exchange resins have been used in removing aqueous nitrate, but their application has been limited by the spent resins and the brine-waste. In this work, the regeneration of nitrate-laden resin using denitrifying bacteria was investigated for the reuse of the spent resin without brine-waste discharge. The results indicate that the bio-regeneration contains two mainly processes of chemical regeneration (ion exchange) and bio-degradation (denitrification), in which the denitrification related to the inoculum amount was the limiting factor of bio-regeneration. The bio-regeneration time was reduced to about 4.0 h with increasing inoculum amount to 2.2 g VSS/L. It also reduced from more than 50.0 h–4.0 h with the decreasing resin amount from 5.0 g to 0.2 g in the saturation of 35.5 mg/g, and reduced from 12.0 h to 3.0 h with the resin saturation from 27.4 mg/g to 2.70 mg/g in the resin amount of 0.2 g under the inoculum amount of 2.8 g VSS/L. The comparation of bio-degradation rate between data with different resin amount and data with different resin saturation suggested that the spent resin with a high degree of saturation is favorable to bio-regeneration. The bio-regenerated resin can be reused with 11.6% of capacity loss in the initial 5 cycles and gradually reach a stable reusability. This decrease was attributed to the adsorption of protein-like substances onto resin rather than biomass attachment onto resin. This study proposes the reuse of spent resin by bio-regeneration in a reuse mode for the aqueous nitrate removal, with at least 87.5% reduction on the production of waste water from bio-regeneration process.

Black soldier fly larvae (BSFL), high-fat-containing insects, are a promising non-edible feedstock for biodiesel production. Extracting fat from BSFL biomass for biodiesel production by using traditional methods requires a high amount of solvent, long extraction time, and thermal conditions. To address these limitations, this study proposed an enzyme-assisted extraction method for extracting fat from BSFL biomass for biodiesel production. Different proteases were used to pretreated BSFL biomass prior to the extraction by n-hexane. Among the tested enzymes, Protamex was the most effective for the pretreatment, resulting in the highest fat yield (2.2-fold increase in the fat yield, compared with the extraction without enzymatic treatment). The extraction of insect fat using Protamex-assisted pretreatment was then optimized using response surface methodology (RSM). A four-factor, three-level Box–Behnken design was employed to optimize the factors for the highest fat yield using 27 experimental runs. The optimized conditions were water-to-biomass weight ratio of 4.33:1, enzyme amount of 3.85%, enzymatic treatment temperature of 38.1 °C, and enzymatic treatment time of 4.27 h for a maximum fat yield of 36.09%. The extracted BSFL fat was then used as feedstock for producing biodiesel. Most properties of the synthesized biodiesel met American Society for Testing and Materials (ASTM) specification D6751 and European standard EN 14214. The enzyme-assisted extraction process was then proposed for use in large-scale operations to evaluate its economic feasibility, revealing promising industrial applications. This study suggests that the enzyme-assisted extraction is an efficient method for extracting insect fat, and the extracted fat has potential for use as oil for biodiesel production.

Desulfurization is important to the enhancement of biodiesel quality. In this study, the effects of reactant and catalyst addition and operations conducted on sulfur content at each stage during the biodiesel preparation process were examined. Based on the results of sulfide qualification and quantification, a high vacuum distillation method was developed to remove the sulfides in crude biodiesel. Biodiesel was separated into different fractions based on the boiling point and the sulfur content of each fraction was determined. Experimental results showed that most sulfides were distilled out with light and heavy fractions. Intermediate fraction was separated from the other fractions, resulting in high quality biodiesel with low sulfur content. The total yield of distillation fractions with sulfur content lower than 10 ppm reached 84.1%. A set of distillation facility with capacity of 10 m3/h was designed and developed accordingly for large-scale tests. The yield of low-sulfur biodiesel was around 83%, close to that obtained in the laboratory studies. In addition, economic analysis showed that the distillation facility can make revenue of more than $1.8 million per year, indicating that high vacuum distillation is economically feasible and promising for biodiesel desulfurization, especially in industrial application.

Waste-to-energy conversion is an environmentally friendly way for disposing of sewage sludge (SS), with this study investigating the use of rice husk (RH) and wood sawdust (WS) as agricultural/forestry wastes for production of sludge-based refuse-derived fuel (RDF). Thermogravimetric and mass spectrometric (TG-MS) analysis has been used to investigate the combustion characteristic, interactions and kinetics of the RDFs, with the gaseous emissions produced during combustion being analyzed. These results reveal that introduction of RH and WS can improve the combustion stability, burnout characteristics and SO2 emission, however, higher NOx (NO and NO2) levels are produced. Interactions within the fuel promote combustion of volatiles and the release of SO2 and NO, with a reduction in the reaction of char, as well as the generation of NO2. Addition of biomass leads to an increase in activation energy of the combustion process for RDF relative to SS, particularly in the presence of RH. Diffusion, interfacial reactions and nucleation processes were shown to be the dominant factors affecting the combustion kinetics of RDF.

The reuse opportunities of separate wastewater streams and end-of-pipe composite wastewater were investigated in an integrated woolen textile mill. The main purpose was to reuse either the treated composite wastewater and/or treated/untreated separate streams depending on the water quality demand of different water use points in the production processes. In this context, three separate wastewater streams (tops-fiber, bobbins thread and fabric dyeing-finishing wastewaters) and composite wastewater were analyzed in terms of quality and quantity. Moreover, raw groundwater, softened process water, cationic ion exchangers’ regeneration wastewater, and reverse osmosis (RO) concentrates were also characterized. Wastewater treatability studies were conducted in pilot-scale employing membrane bioreactor (MBR), nanofiltration (NF) and brackish water reverse osmosis (BWRO) processes at different test conditions. In the wastewater characterization studies, peaks and oscillations were found in the separate wastewater streams depending on the production schedules and applied dyeing recipes. Therefore, due to mixing effects of separate streams, it was decided to employ pilot-scale treatability tests on the composite wastewater. In the MBR process, the average chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), and color removals were 70, 74, 86, 28, 43, and 62%, respectively. In MBR + NF and MBR + RO tests, the removals of all analyzed parameters were 40–99 and 52–99%, respectively. The pH, conductivity, turbidity, color, and TN concentrations in MBR + RO effluent were 7.6–7.8, 57–65 μS/cm, 0.6–1.2 NTU, 25–44 Pt Co, and 14–16 mg/L, respectively. In addition, the COD, BOD5 and total hardness values were found under 1 mg/L. The treated water was finally disinfected with ultraviolet (UV) light to ensure microbial safety before reuse in dyeing process. Treated water samples were tested in different dyeing recipes in lab-scale to determine their impacts on woolen textile product quality. Dry-wet rubbing, water fastness, dry-cleaning and alkali-acid perspiration fastness tests were performed on the fabrics dyed with MBR + UV, MBR + NF + UV and MBR + RO + UV effluents and the results were compared with those dyed with process water (softened groundwater). It was found that especially MBR + NF + UV and MBR + RO + UV effluents did not negatively affect product quality. Surprisingly, the color depth was increased in some shades with MBR + UV effluent, possibly due to the presence of already existing salts. Overall, the product quality tests with reclaimed wastewaters exhibited very promising results. Therefore, capital and operational costs were estimated for a potential full-scale wastewater treatment and reclamation plant in the textile mill.

The replacement of fossil fuel through renewable resources is the need of the hour to reduce environmental pollution. Biodiesel is one of the renewable sources to replace fossil fuel but its properties are influenced by fatty acids composition, production process, atmospheric and tropical conditions. An attempt has been made to improve biodiesel quality through the bio-mix approach. Bio-mix is a simple method to improve the saturation level by decreasing unsaturated fatty acid composition. In this investigation, the raw bio-mix oil (RBMO) was derived from the raw mixture of edible and non-edible oils and transesterified to form bio-mix methyl ester (BMME). Two samples of BMME fuel were prepared, BMME-I from the ternary mixture of raw oil feedstock: Jatropha, Karanja, Cottonseed oil and BMME-II from the quaternary mixture of raw oils feedstock: Jatropha, Karanja, Palm, Coconut and oils respectively. Gas chromatography-mass spectrometry (GC-MS) was used to analyze fatty acids composition for characterization of BMME fuel. Fuel properties of biodiesel were measured and found within the standards limit (ASTM D6751, EN14214, and BIS IS15607-05). Results showed that saturated fatty acids, cetane number, oxidation stability increased whereas density, viscosity, heating value, flash point, iodine number, and acid number decreased as compared to individual biodiesel feedstock respectively. The biodiesel derived from non-edible oil feedstock has to be esterified prior to transesterification to reduced acid value and free fatty acids. Raw bio-mix oil consists of a lower acid value and free fatty acids, hence directly transesterified and reduced the pre and post-treatment process. This study suggested that Bio-Mix Methyl Ester (BMME) could be a suitable model to prepare low cost and good quality biodiesel for compression ignition (CI) engine application.

The motivation behind this work is to sustainable utilization of water-cooled steel-slag and lead-bearing sludge (LBS: from glass crystal industry) in the cleaner production of alkali activated cement (AAC) with high performance and microbial resistivity. To prepare AAC, slag was individually blended with different LBS contents (0, 10, 30, and 50% with respect to weight of slag), then activated with sodium hydroxide (NaOH). Due to high CO2 emission resulting from NaOH-manufacturing, alkali activator was used with low concentration (3 wt, %) for activating the aluminosilicate precursors. A preliminary investigation proved that the mechanical and physical properties of AAC significantly enhanced with the increase of LBS content up to 30 wt %; meanwhile, 50 wt % LBS had a negative effect. The leaching test indicated that Pb-concentrations (mg/l) in leachate of all AAC-mixtures were below the safe limit of toxicity characteristic leaching procedure (TCLP). Agar diffusion test showed that the anti-bacterial and -fungal activity of AAC enhanced with increasing LBS content up to 50 wt %. From the standpoint of environmental impact assessment, the prepared cement showed 50-times lower CO2 emission compared with Portland cement.

Production of microalgal biomass for feed and fuels demands unsustainable large amounts of fertilizers. The most broadly considered alternative sources of nutrients/fertilizer for microalgae are wastewater and internal recycling in closed-loop production platforms. However, these strategies largely disable co-production of feed and fuel in biomass biorefineries for an increased economic and environmental feasibility. In this study, we aimed at providing proof-of-concept for a semi-closed loop microalgal production-platform and biomass biorefinery for ethanol and feed from renewable resources of N and P. Atmospheric N 2 was assimilated into a N 2 -fixing cyanobacterial biomass, which sustained growth of a microalga that accumulated high levels of carbohydrates (up to 60% (w/w)) as a sole source of fertilizer. The microalgal biomass was efficiently saccharified with H 2 SO 4 , which was recycled to release soluble PO 4 3- from bone meal as a renewable source of P. Fermenting these P-enriched preparations with yeasts quantitatively produced ethanol at theoretical yields, a concentration of up to 50 g ethanol. L −1 and a yield of 0.25 g ethanol. g biomass −1 . Calculations suggested a potential yield from 7600 to 10,800 L ethanol. ha −1 . year −1 , under Buenos Aires environmental conditions, which would be higher than that currently obtained from maize feedstocks. The residual fermentation vinasse, supplemented with P and containing other downstream-process reagents, was recycled as a sole source of macronutrients for the cultivation of the N 2 -fixing cyanobacterium to close the production cycle. Water recycling and co-production of residual biomass enriched in fat and protein as potential feed are also shown. This semi-closed loop biomass production-platform reconciles the concepts of microalgal biomass biorefineries for the co-production of feedstocks for biofuels and feed and nutrients recycling in closed-loop systems that largely minimizes production of waste. Fil: Sánchez Rizza, Lara. Fundación para Investigaciones Biológicas Aplicadas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina Fil: Coronel, Camila Denise. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina Fil: Sanz Smachetti, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina Fil: Do Nascimento, Mauro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina. Fundación para Investigaciones Biológicas Aplicadas; Argentina Fil: Curatti, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentina

With painting operations as a major origin of environmental concerns in automotive industry, novel and effective technologies are required for treatment of automotive paint wastewater. In this experimental study, a continuous-flow electroflotation reactor with effective volume of 38.4 L and stainless-steel electrodes were designed and implemented for treatment of this industrial wastewater. The system performance, namely the total suspended solids removal, was investigated with operational parameters including the hydraulic retention time, current density and influent total solids concentration. The removal rate ranged between 57 ± 1% and 95 ± 7% under initial total solids concentration 3000 mg/L, current density 50 A/m2, retention time 4 min, and initial total solids concentration 500 mg/L, current density 100 A/m2, retention time 8 min conditions, respectively. It was found that the removal rate decreases with the increase of influent total solids concentration. The results revealed that the suspended solids removal rate is directly related to the applied current density and hydraulic retention time. The electroflotation system showed to be energy-efficient compared to the commercial systems. Further, an empirical equation for the total suspended solids removal rate was established with the R2 value of 92.74%. The independent variables were the retention time, influent suspended solids concentration and applied current density.

Several studies have focused in the tannery industry due to the high polluting potential of the effluent generated in leather processing; high concentrations of total chromium and organic load. However, the high costs attributed to the treatment of tanning residues explains why this material is not treated within the tannery industry. The extract from the flower of Musa sp, condensed and hydrolisable tanins, yet to be explored in literature was applied to remove organic matter from chemically enhanced primary treatment (CEPT) of total solids, turbidity and total chromium from a tanning industry and leather processing. The use of the flower extract of Musa sp. proposed in this study does not require flocculant polymers after the coagulation step. A central composite design response surface (CCD) was modelled by the factors: coagulant volume, pH and rotation. The optimization was performed according to the NBI algorithm in a mixed arrangement to determine optimal weights. The modeling from CCD and minimization of Global Standard Error determines the optimized conditions, turbidity removal, total cromium, hexavalent chromium and trivalente chromium of 78% and 65.4%, 39.43% and 61.02%, respectively, increasing the biodegradability from the ratio biochemical oxygen demand (COD) and chemical oxygen demand (COD) of 0.12–0.63.

The heavy use of coal-derived coke (CDC) in steel industry makes it a major contributor to the greenhouse emissions. With the impact of global warming knocking our doors, the CDC has experienced supply shortages and increasing costs. Such scenario has raised the need to find a sustainable and renewable replacement to CDC. Hard-wood biomass has emerged as a promising alternative to the CDC. While such sources of virgin biomass remain at high cost, other types of agro-industrial residues constitute an opportunity for further sustainable utilization. In the current work, we have assessed the suitability of an abundant source of biomass waste, i.e., lignin-rich press mud (LPM), for steel industry. Hard carbons were obtained from LPM through a thermal treatment at a wide range of temperatures, and the chemical content (i.e., impurity) of all carbons was compatible with the steel making process. Before fitting the LPM-derived carbons (LPMCs) for such purpose, several carbon properties (e.g., chemical content and reactivity) and carbon-steel interactions (e.g., iron oxide/slag reduction, steel carburizing) were comprehensively studied and evaluated. The LPMC obtained at high temperature has particularly demonstrated an excellent reduction performance and desirable slag interactions compared to a typical metallurgical coke. The diffusion of S from LPMC into steel was an issue raised and discussed in this study. The reduction of S in LPMC was demonstrated and a subsequent enhanced C uptake in steel of 2.38% was achieved.

In this study, a pilot-scale ultrafiltration membrane system was developed for harvesting of oleaginous Scenedesmus acuminatus by adjusting transmembrane pressure-TMP (cross flow velocity-CFV changed accordingly) and applying air-assisted backwashing technology to increase membrane flux, reduce flux declining rate and enhance flux recovery rate. A two-stage harvesting strategy (normal filtration–strengthening concentration) was performed for harvesting of 53 m3 of S. acuminatus suspension to achieve both high flux and concentration factor. The results showed that TMP (CFV) had positive impact on average flux, and the increase could effectively overcome the decrease in average flux when harvesting microzooplankton contaminated S. acuminatus culture. Shortening the interval of air-assisted backwashing to 15 min enhanced the average flux up to 12%. The average flux decreased with the increased loading volume, and volumetric reduction factor had a negative effect on average flux. For the harvesting of 53 m3 of S. acuminatus suspension, an average membrane flux reached up to 53.6 L/(m2·h), with a concentration factor of 145, a final dry weight of 136 g/L, and a biomass recovery of 93% after backwashing. Techno-economic analysis for annual harvesting capacity of 10000 t dry biomass showed that the total harvesting cost was $0.30/kg dry microalgal biomass with a volumetric reduction factor of 50, and membrane harvesting under CFV of 0.5–0.6 m/s may lead to a moderate flux of 60–66.6 L/(m2·h) and minimal total cost of $0.27/kg dry biomass based on the sensitivity analysis. The results of this study suggest that this clean and efficient ultrafiltration membrane approach has high industrialization potential.

Separation and treatment of human urine from domestic wastewater have been recognized as a sustainable alternative to conventional urban sanitation system, but the unique water quality of source-separated urine, such as high nutrient, insufficient alkalinity and low COD/nitrogen ratio, poses challenges to the biological nitrogen removal process. It was hypothesized that a physicochemical pre-treatment should be adopted to not only reduce nitrogen load but adjust water quality suitable for biological treatment. In this study, a vacuum thermal stripping process coupled to acid absorption was used as a pre-treatment to recover ammonia from hydrolyzed urine in the form of ammonium sulphate. The maximal ammonia mass transfer coefficient of 17.6 mm/h was obtained under 60 °C and 21.3 kPa 80% of the nitrogen in hydrolyzed urine was recovered in 3 h batch stripping experiments without pH adjustment, corresponding to a nitrogen recovery loading rate of 36 kg N/m3⋅d. The majority of organic matters were retained in urine solutions, thus COD/N and alkalinity/NH4+ N ratios were elevated to 4.75 and 4.37, respectively. Phosphorus recovery could be simultaneously obtained in stripping process by adding MgCl2. The remaining nitrogen was effectively removed via short-cut nitrification and denitrification in an anoxic/oxic membrane bioreactor. More than 95% of overall nutrient recovery/removal from urine was achieved with a minimal consumption of external resources. The economic assessment of the technique showed that the recovery/removal of nutrients from 1 m3 of urine can make a profit of € 0.26.

Palm oil mill effluent (POME) is a highly polluted industrial wastewater that may cause detrimental environmental pollution if discharged directly due to its biochemical oxygen demand (BOD) and chemical oxygen demand (COD) concentrations. In the present study, the performance of FeSO4.7H2O waste from titanium oxide industry was investigated in removing BOD, COD, and total suspended solids (TSS) from POME. Jar tests were conducted with varying coagulant doses (1–5 g L−1), pH (2–10), and temperature (40–80 °C) as a function of treatment time ranging from 5 to 90 min. Results show that the FeSO4.7H2O waste can remove about 70% COD, over 80% BOD, and over 85% TSS in a single stage coagulation treatment. The coagulation adsorption mechanisms for the removal of COD, BOD, and TSS from POME were investigated based on Brunauer–Emmett–Teller (BET), Freundlich, and Langmuir isotherm models. The removal of COD, BOD, and TSS from POME was best described by the Freundlich isotherm model, indicating that coagulation adsorption occurred in a multilayer formation with non-uniform distribution of adsorbed particles. The coagulation adsorption kinetics studies revealed that the removal of COD, BOD, and TSS from POME using FeSO4.7H2O waste followed the second-order-kinetics modeling. Our findings suggest that the FeSO4.7H2O waste has the potential to be utilized as a coagulant for treating POME in compliance with the standard discharge limits.

In this study, a novel modeling approach (artificial neural networks (ANN) and ant colony optimization (ACO)) was used to optimize the process variables for alkaline-catalyzed transesterification of CI40CP60 oil mixture (40 wt% of Calophyllum inophyllum oil mixed with 60 wt% of Ceiba pentandra oil) in order to maximize the biodiesel yield. The optimum values of the methanol-to-oil molar ratio, potassium hydroxide catalyst concentration, and reaction time predicted by the ANN-ACO model are 37%, 0.78 wt%, and 153 min, respectively, at a constant reaction temperature and stirring speed of 60 °C and 1000 rpm, respectively. The ANN-ACO model was validated by performing independent experiments to produce the CI40CP60 methyl ester (CICPME) using the optimum transesterification process variables predicted by the ANN-ACO model. There is very good agreement between the average CICPME yield determined from experiments (95.18%) and the maximum CICPME yield predicted by the ANN-ACO model (95.87%) for the same optimum values of process variables, which corresponds to a difference of 0.69%. Even though the ANN-ACO model is only implemented to optimize the transesterification of process variables in this study. It is believed that the model can be used to optimize other biodiesel production processes such as seed oil extraction and acid-catalyzed esterification for various types of biodiesels and biodiesel blends.

The recycling process of materials from used and wasted printed circuit boards plays an important role in electronic waste management. These waste printed circuit boards (PCBs) hold metals such as copper, aluminium, nickel, and magnesium. The efficient recovery process of such metals from waste PCBs is needed for recycle and possible reuse for manufacturing of products. The metal recovery process is complex and, multidimensional and costly to perform. In addition, the efficient (maximum) recovery of metals exhibit higher dependence on determination of optimum combination of inputs in the recovery process from waste PCBs. Therefore, this work illustrated the ability of four predictive modelling methods (Analysis of Variance, Genetic Programming, Artificial Neural Network and Generalized Neural Network) to model complex suspension electrolysis process (recovery process) and their comparative analysis on recovery of copper metal from waste PCBs. Experiments were designed based on variations of three design/input parameters such as concentration of sulfuric acid, concentration of copper sulphate and current density. The comparative analysis of the four methods mentioned above reveals that Generalized Neural Network performed the best with coefficient of determination value at 0.92. 3-D surface contour analysis showed that a lower concentration of sulfuric acid (0.3–0.6) coupled with higher concentrations of copper sulfate (∼0.8–1) yielded a higher percentage of copper. However, current density brought an increase in copper recovery only when there was a corresponding increase in the concentration of sulfuric acid or copper sulphate. Thus, the optimal conditions to gain the maximum yield of copper obtained through this method were concluded as follows: concentration of copper sulphate value at 31.4 g/L, concentration of sulfuric acid at 112 g/L and current density at 3 A/dm2.

Biogas production is known to be the most sustainable bioenergy technology available owing to its utilization of waste biomass. Due to the widely ranging energy contents of major organic carbons and their diverse degradation pathways, as well as their highly varying hydrolysis capacities, predicting methane yield is not as simple as predicting the production of other biofuels. This study investigated the hydrolysis behaviour of organic compounds using the operational conditions of real-scale biogas plants (hydraulic retention time (HRT) of 15, 20, 30, and 45 days) and explored a new approach to determine the biochemical methane potential (BMP), which can be used to predict the methane yield of a wide range of agro-industrial wastes. The degradation of hemicelluloses and cellulose increased gradually, closely following first-order degradation kinetics, at longer retention times. In spite of their longer retention times, only 45% of hemicelluloses and 34% of cellulose decomposed. The newly proposed BMP model was validated using 65 internal and external datasets. The model error (RMSE P ) was in the range of 37.4–87.7 NL CH 4 kg VS −1 while the relative model error (rRMSE P ) was in the range of 12.1%–47.8%. The model fits best to gently lignified biomass, but the overestimated results obtained with woody biomass and winter harvested grass indicate that further investigation of the hydrolysis of well-lignified biomass is required to enhance the precision of the model.

The rapid depletion of natural resources has led to the need to develop sustainable practices and material in various applications. One such sustainable practice is to divert the waste generated in the palm oil industry into production of building materials. In this study, palm oil clinker (POC) is used to replace cement and coarse aggregate. The POC chunks are crushed to be used as coarse aggregate and further ground to produce POC powder (POCP) to be used as a binder. The physical properties, chemical composition and scanning electronic microscopic studies were conducted to check the feasibility of substitution of up to 50% POCP as binder and up to 100% POC as coarse aggregate. Density, ultrsonic pulse velocity(UPV), compressive strength for air & water curing, flexural, tensile strength, modulus of elasticity in water cured regimes and structural efficiency were evaluated for the samples. Carbon footprint, cost effieciency and energy savings were also evaluated to understand the contribution of POC to sustainability. The results revealed that the ideal mixture of GPP (30% POCP & 50% POC) masonry grout achieved 79% of compressive strength, a 83% of flexural strength, 85% of tensile strength and about 85.5% of modulus elasticity, as compared to control masonry grout. Carbon emissions of GPP was reduced by 21% and 14.60% cost reduction was established, in addition, appreciable energy savings was notified. The study showed that that utilisation of POC as eco-friendly material in masonry grout is highly recommended based on performance and can provide a route to sustanable practices in the building industry.

Walnut shell is a common agricultural by-products for the production of biochar. In this study, the walnut shell was investigated by thermoanalytical methods to evaluate its thermal behavior; and the biochar was prepared from the pyrolysis at 600 °C. Biochar characterization was studied in detail, and proximate analysis result indicates that the biochar obtained from walnut shell has a high fixed carbon content, lower ash content. The biochar was used as a reductant to reduce the waste copper slag for recovering iron. The reduction process of copper slag by biochar was analyzed theoretically, and the iron in the slag was recovered efficiently by reduction and magnetic separation method. The phase transformation of the reduced slag and the kinetics of reduction process were analyzed during the reduction process with biochar. The research results suggest that biochar derived from walnut shell can be used as a green reductant to reduce iron phase in the waste copper slag and realize the clean utilization of hazardous waste.

This study approached the use of atmospheric emissions as a source of carbon for the cultivation of microalgae in high rate ponds (HRPs), continuously fed with domestic sewage pre-treated in a septic tank. To do so, two HRPs were used: one had CO2 at a concentration of 99.9% (HRP 1), and the other had gas from the combustion of gasoline (HRP 2). Biomass yield, sewage treatment efficiency and the economic viability of using these two sources were assessed. The results showed that the CO2 source did not influence the domestic sewage treatment or the yield and biochemical composition of biomass, since there was no statistical difference (p

Galician “Rias”·conditions (extension, water temperature …. ) enable the production of excellent quality cultured mussels. This leads Spain to be the third producer country in the world. Cannery industry (35% of the total cultured mussel production) generates 25000 tons of mussel shell waste per year. Hence, it is necessary to find a sustainable use for this material. The purpose of this work is to verify the most significant changes in the properties of air lime coating mortar when replacing limestone sand with mussel shell sand. Two different air limes have been used: non-aged hydrated commercial lime powder and 10 month-old slaked lime putty. Reference mortars and mortars with mussel shell aggregate as a substitute for limestone aggregate at different rates - 25%, 50% and 75% - have been tested. The behaviour of mortars at the age of one year from kneading has been studied. Studies show that mussel shell increases the pore volume of air lime mortar mixtures, which means a reduction in the mortar's workability and density. The poor paste-aggregate cohesion of mussel shell particles in the air lime matrix worsen the mortar mechanical strength results, which is confirmed by ultrasound test results. Carbonation at this age and hygric behaviour are properties that improve with mussel shell content.

In this study, an extensive examination of ammonium removal and recovery from highly concentrated digestate wastewater was systematically performed. The treatability and ammonium recovery potential of the real digestate wastewater was assessed by enhanced Flowed Channel Membrane Capacitive Deionization (fcMCDI), which was introduced in our previous study. The fcMCDI cell was found efficient to remove ammonium ions from a synthetic mixture of glucose and Ca2+ and Na+ ions, which are the major components of the anaerobic digestate liquid. Specific ammonium removal performance of the system was investigated in the presence of other ions. In a single cycle experiment, the process was able to remove the Mg2+, Ca2+, K+ and NH4+ ions from real digestate wastewater at percentages of 90.4%, 85%, 67.9% and 54.4%, respectively. A comparison of the conventional MCDI operation with an increased voltage application method with the fcMCDI cell was presented. Ammonium was successfully recovered in the form of ammonia gas by increasing the cell's working voltage, and simultaneous deionization of the other ions in the digestate wastewater was achieved. The obtained ammonium removal efficiencies were 89% and 67% with synthetic and real digestate wastewater, respectively. The results demonstrated that the enhanced MCDI technology holds a great potential to be an energy-efficient process for ammonium removal and recovery while also removing other contaminants effectively from highly concentrated wastewater sources. (C) 2019 Elsevier Ltd. All rights reserved.