Excessive accumulation of waste materials has presented a serious environmental problem on a global scale. This has prompted many researchers to utilise agricultural, industrial, and by-product waste materials as the replacement of aggregate in the concrete matrix. In this present study, the prediction and optimisation of coconut shell (CA) content as the replacement of fine aggregate were evaluated based on the mechanical properties of the concrete (M30). Based on the suggested design array from the response surface methodology (RSM) model, experimental tests were carried out to achieve the goal of this study. The collected data was used to develop mathematical predictive equations using both GEP and RSM models. Analysis of variance (ANOVA) was also taken into account to appraise and verify the performance of the proposed models. Based on the results, the optimum content of replacing CA was 50%. In particular, the compressive, tensile, and flexural strength obtained after 28 days of curing were 46.2, 3.74, and 8.06 MPa, respectively, from the RSM model and 46.18, 3.85, and 7.99 MPa, respectively, from the GEP model. The obtained values were superior to those of the control concrete sample (43.12, 3.51 and 7.14 MPa, respectively). Beyond the optimum content, a loss in strength was observed. It was also found that both the GEP and RSM models exhibited high prediction accuracy with strong correlations (R2 = 0.97 and 0.95, respectively). In addition, minimum prediction error (RMSE
This article presents a comprehensive overview of upcycling commercial nut byproducts (such as Brazil nut, cashew, hazelnut, macadamia, peanut (also known as a legume), pecan, pine nut, pistachio, and walnut) for food, nutraceutical, and pharmaceutical applications. Upcycling nut byproducts, namely husk/hull, hard shell, brown skin, defatted flour/meal/cake, pine cone, cashew nut shell liquid, cashew apple, walnut septum, and dreg/okara, has great potential, not only to reduce/minimise waste, but also to fit within the circular economy concept. Each byproduct has its own unique functional properties, which can bring significant value. These byproducts can be used as value-added ingredients to promote better health and well-being, due to their rich sources of diverse bioactive components/phytochemicals, polysaccharides, fibre, lignin, prebiotics, oils, proteins, bioactive peptides, minerals, and vitamins, among other components. This comprehensive review provides a basis for future research and development of product applications for nut byproducts. More studies are needed on novel product development to valorise nut byproducts.
Floating plastic debris was investigated in the transition region in the North Pacific between 141°E and 165°W to understand its transportation process from Asian coast to central subtropical Pacific. Distribution was influenced primarily by the current system and the generation process of the high concentration area differed between the western and eastern areas. West of 180°, debris largely accumulated around nearshore convergent area and was transported by eddies and quasi-stationary jet from south to the subarctic region. The average was 15% higher than that previously reported in 1989, suggesting an increase in plastic debris in 30 years. East of 180°, debris concentrated in the calm water downstream of the Kuroshio Extension Bifurcation with considerably high concentration (505,032 ± 991,989 pieces km-2), due to the accumulation of small transparent film caused by calm weather conditions, suggesting a further investigation on small plastic (<1 mm) in the subsurface depth in the subtropical North Pacific.
Southeast (SE) Asia is a highly biodiverse region, yet it is also estimated to cumulatively contribute a third of the total global marine plastic pollution. This threat is known to have adverse impacts on marine megafauna, however, understanding of its impacts has recently been highlighted as a priority for research in the region. To address this knowledge gap, a structured literature review was conducted for species of cartilaginous fishes, marine mammals, marine reptiles, and seabirds present in SE Asia, collating cases on a global scale to allow for comparison, coupled with a regional expert elicitation to gather additional published and grey literature cases which would have been omitted during the structured literature review. Of the 380 marine megafauna species present in SE Asia, but also studied elsewhere, we found that 9.1 % and 4.5 % of all publications documenting plastic entanglement (n = 55) and ingestion (n = 291) were conducted in SE Asian countries. At the species level, published cases of entanglement from SE Asian countries were available for 10 % or less of species within each taxonomic group. Additionally, published ingestion cases were available primarily for marine mammals and were lacking entirely for seabirds in the region. The regional expert elicitation led to entanglement and ingestion cases from SE Asian countries being documented in 10 and 15 additional species respectively, highlighting the utility of a broader approach to data synthesis. While the scale of the plastic pollution in SE Asia is of particular concern for marine ecosystems, knowledge of its interactions and impacts on marine megafauna lags behind other areas of the world, even after the inclusion of a regional expert elicitation. Additional funding to help collate baseline data are critically needed to inform policy and solutions towards limiting the interactions of marine megafauna and plastic pollution in SE Asia.
Solid waste collection and disposal are among the most vital services provided to about 700 770 residents of the city of Erbil in northern Iraq. As such, proper waste management systems that consider both the quantity and composition of domestic solid waste are strongly required to address the increasing amount of solid waste. Unfortunately, these essential data are not easily available. The present study sought to gather data on the quantity and composition of domestic solid waste collected from different quarters in Erbil, and the feasibility of recycling these wastes. The solid waste generation rate (GR), uncompacted density, and weight percentages of combustible and incombustible materials were determined based on the collected materials (i.e., food, plastic, paper, metal, glass and cloth). The results show that the average GR and uncompacted density were 0.654 kg capita(-1) day(-1) and 175.72 kg m(-3), respectively. The weight percentages of food, plastic, paper, metal, glass, and cloth as components of domestic solid waste were 79.34, 6.28, 5.9, 3.6, 3.42 and 1.45%, respectively.
The integration of communication technologies such as radio frequency identification (RFID), global positioning system (GPS), general packet radio system (GPRS), and geographic information system (GIS) with a camera are constructed for solid waste monitoring system. The aim is to improve the way of responding to customer's inquiry and emergency cases and estimate the solid waste amount without any involvement of the truck driver. The proposed system consists of RFID tag mounted on the bin, RFID reader as in truck, GPRS/GSM as web server, and GIS as map server, database server, and control server. The tracking devices mounted in the trucks collect location information in real time via the GPS. This information is transferred continuously through GPRS to a central database. The users are able to view the current location of each truck in the collection stage via a web-based application and thereby manage the fleet. The trucks positions and trash bin information are displayed on a digital map, which is made available by a map server. Thus, the solid waste of the bin and the truck are being monitored using the developed system.
The valorization process involves transforming low-value materials such as wastes into high-value-added products. The current study aims to determine the potential of using a valorization process such as vermicomposting technology to convert palm oil mill byproduct, namely, decanter cake (DC), into organic fertilizer or vermicompost. The maturity of the vermicompost was characterized through various chemical and instrumental characterization to ensure the end product was safe and beneficial for agricultural application. The vermicomposting of DC showed significantly higher nutrient recovery and decreases in C:N ratio in comparison with the controls, particularly in the treatment with 2 parts DC and 1 part rice straw (w/w) (2DC:1RS). 2DC:1RS vermicompost had a final C:N ratio of 9.03 ± 0.12 and reasonably high levels of calcium (1.13 ± 0.05 g/kg), potassium (25.47 ± 0.32 g/kg), magnesium (4.87 ± 0.19 g/kg), sodium (7.40 ± 0.03 g/kg), and phosphorus (3.62 ± 0.27 g/kg). In addition, instrumental characterization also revealed a higher degree of maturity in the vermicompost. Ratios of 2921:1633 and DTG2:DTG3 also showed significant linear correlations with the C:N ratio, implying that those ratios could be used to characterize the progression of vermicompost maturity during the valorization process of DC.
Polyhydroxyalkanoate (PHA) is a family of microbial polyesters that is completely biodegradable and possesses the mechanical and thermal properties of some commonly used petrochemical-based plastics. Therefore, PHA is attractive as a biodegradable thermoplastic. It has always been a challenge to commercialize PHA due to the high cost involved in the biosynthesis of PHA via bacterial fermentation and the subsequent purification of the synthesized PHA from bacterial cells. Innovative enterprise by researchers from various disciplines over several decades successfully reduced the cost of PHA production through the efficient use of cheap and renewable feedstock, precisely controlled fermentation process, and customized bacterial strains. Despite the fact that PHA yields have been improved tremendously, the recovery and purification processes of PHA from bacterial cells remain exhaustive and require large amounts of water and high energy input besides some chemicals. In addition, the residual cell biomass ends up as waste that needs to be treated. We have found that some animals can readily feed on the dried bacterial cells that contain PHA granules. The digestive system of the animals is able to assimilate the bacterial cells but not the PHA granules which are excreted in the form of fecal pellets, thus resulting in partial recovery and purification of PHA. In this mini-review, we will discuss this new concept of biological recovery, the selection of the animal model for biological recovery, and the properties and possible applications of the biologically recovered PHA.
The first report on the emergence of microplastic in Malaysian marine waters was documented in this study. Water samples were collected from two regions, namely Kuala Nerus and Kuantan port, as the representatives of different anthropogenic activities. Identification of microplastic was performed based on physical characteristics (colour, shape, density) and chemical characterisation (ATR-FTIR analysis) for a functional group of polymers. Fragment type, black or grey colour and high density (>1.02 g cm-3) of microplastic were the most prevalent characteristics found in both areas. Two principal components (density and colour) rendered explained about 95.3% (Kuantan) and 95.6% (Kuala Nerus) of the total variance. Six possible polymer materials were identified, namely polyester, polystyrene, polyamide, polyvinyl chloride, polypropylene, and polyethylene. The findings of the study provided good baseline information on marine debris issue in Malaysia.
Fruits are important food commodities that can be consumed either raw or processed and are valued for their taste, nutrients, and healthy compounds. Mangifera pajang Kosterm (bambangan) is an underutilized fruit found in Malaysia (Sabah and Sarawak), Brunei, and Indonesia (Kalimantan). It is highly fibrous and juicy with an aromatic flavour and strong smell. In recent years, bambangan fruit has been gaining more attention due to its high fibre, carotenoid content, antioxidant properties, phytochemicals, and medicinal usages. Therefore, the production, trade, and consumption of bambangan fruit could be increased significantly, both domestically and internationally, because of its nutritional value. The identification and quantification of bioactive compounds in bambangan fruit has led to considerable interest among scientists. Bambangan fruit and its waste, especially its seeds and peels, are considered cheap sources of valuable food and are considered nutraceutical ingredients that could be used to prevent various diseases. The use of bambangan fruit waste co-products for the production of bioactive components is an important step towards sustainable development. This is an updated report on the nutritional composition and health-promoting phytochemicals of bambangan fruit and its co-products that explores their potential utilization. This review reveals that bambangan fruit and its co-products could be used as ingredients of dietary fibre powder or could be incorporated into food products (biscuits and macaroni) to enhance their nutraceutical properties.
The feasibility of using waste glycerol from the biodiesel industry for biosynthesis of polyhydroxyalkanoate (PHA) by Burkholderia cepacia BPT1213 was evaluated. Culture conditions were optimized by growing B. cepacia BPT1213 in mineral salt medium supplemented with 2% waste glycerol in a 2.5 L bioreactor. Response surface methodology was used to determine the influence of aeration rate (0.6-1.8 vvm), agitation speed (100-300 rpm), and cultivation period (48-72 hr) on PHA production. The optimum conditions for the growth and PHA accumulation were 1.5 vvm, 300 rpm, and 72 hr, with predicted values of 5.08 g/L cell dry weight (CDW), 66.07% PHA content, and 3.35 g/L total PHA concentration. Using these conditions, the experimental system produced 5.63 g/L of CDW with 64.00% wt/wt PHA content, which is threefold higher PHA concentration (3.60 g/L) compared to the non-optimized conditions. The melting temperature (Tm ) of purified PHA was 173.45 ± 1.05°C. In conclusion, the statistical approach was significantly increased the PHA production using waste glycerol as the sole carbon source.
In a commercial oyster mushroom farm, from 300 g of the total harvest, only the cap and stem of the fruiting body parts are harvested (200 g) while the unused lower section called fruiting-body-base (FBB) is discarded (50 g). A new antioxidative FBB flour (FBBF) conversion to mixed-ratio chicken patty was recently developed which converts 16.67% of FBB into an edible flour. At the initial stage, pretreatments of FBBF were optimized at particle size (106 µm) and citric acid concentration (0.5 g/100 mL) to improve flour antioxidant responses. Such pretreatments boosted total phenolic content (2.31 ± 0.53 mg GAE/g) and DPPH (51.53 ± 1.51%) of pretreated FBBF. Mixed-ratio chicken patty containing FBBF (10%, 20%, 30%) significantly (P
In this work, two natural sources, including pomegranate peel extract and cochineal dye were employed for the synthesis of silver nanoparticles. The natural silver complex from pomegranate peel extract resulted in nano-sized structures through solution-phase method, but this method was not efficient for cochineal dye-silver precursor and the as-formed products were highly agglomerated. Therefore, an alternative facile solid-state approach was investigated as for both natural precursors and the results showed successful production of well-dispersed nanoparticles with narrow size distribution for cochineal dye-silver precursor. The products were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy dispersive X-ray microanalysis (EDX), and Transmission Electron Microscopy (TEM).
The presence of microplastics in the marine environment poses a great threat to the entire ecosystem and has received much attention lately as the presence has greatly impacted oceans, lakes, seas, rivers, coastal areas and even the Polar Regions. Microplastics are found in most commonly utilized products (primary microplastics), or may originate from the fragmentation of larger plastic debris (secondary microplastics). The material enters the marine environment through terrestrial and land-based activities, especially via runoffs and is known to have great impact on marine organisms as studies have shown that large numbers of marine organisms have been affected by microplastics. Microplastic particles have been found distributed in large numbers in Africa, Asia, Southeast Asia, India, South Africa, North America, and in Europe. This review describes the sources and global distribution of microplastics in the environment, the fate and impact on marine biota, especially the food chain. Furthermore, the control measures discussed are those mapped out by both national and international environmental organizations for combating the impact from microplastics. Identifying the main sources of microplastic pollution in the environment and creating awareness through education at the public, private, and government sectors will go a long way in reducing the entry of microplastics into the environment. Also, knowing the associated behavioral mechanisms will enable better understanding of the impacts for the marine environment. However, a more promising and environmentally safe approach could be provided by exploiting the potentials of microorganisms, especially those of marine origin that can degrade microplastics.
CAPSULE: The concentration, distribution sources and fate of microplastics in the global marine environment were discussed, so also was the impact of microplastics on a wide range of marine biota.
Biosorption potential of mustard oil cake (MOC) for Ni(II) from aqueous medium was studied. Spectroscopic studies showed possible involvement of acidic (hydroxyl, carbonyl and carboxyl) groups in biosorption. Optimum biosorption was observed at pH 8. Contact time, reaction temperature, biosorbent dose and adsorbate concentration showed significant influence. Linear and non-linear isotherms comparison suggests applicability of Temkin model at 303 and 313 K and Freundlich model at 323K. Kinetics studies revealed applicability of Pseudo-second-order model. The process was endothermic and spontaneous. Freundlich constant (n) and activation energy (Ea) values confirm physical nature of the process. The breakthrough and exhaustive capacities for 5 mg/L initial Ni(II) concentration were 0.25 and 4.5 mg/g, while for 10 mg/L initial Ni(II) concentration were 4.5 and 9.5 mg/g, respectively. Batch desorption studies showed maximum Ni(II) recovery in acidic medium. Regeneration studies by batch and column process confirmed reutilization of biomass without appreciable loss in biosorption.
The performance of alkalis (NaOH and Ca(OH)2) and acids (H2SO4, HCl, H3PO4, CH3COOH, and HNO3) in the pretreatment of rice husk was screened, and a suitable reagent was assessed for subsequent optimization using response surface methodology. From the assessment, HCl that hydrolysed rice husk well was optimized with three parameters (HCl loading, pretreatment duration, and temperature) using Box-Behnken Design. The optimized condition (0.5% (w/v) HCl loading, 125 °C, 1.5 h) is relatively mild, and resulted in ~22.3mg TRS/ml hydrolysate. The reduced model developed has good predictability, where the predicted and experimental results differ by only 2%. The comprehensive structural characterization studies that involved FT-IR, XRD, SEM, and BET surface area determination showed that the pretreated rice husk consisted mainly of cellulose and lignin. Compared to untreated rice husk, pretreated rice husk possessed increased pore size and pore volume, which are expected to be beneficial for fungal growth during fermentation.
A size and distance-based technique was used to assess the distribution, abundance and composition of floating marine debris in the northeast Indian Ocean. Densities of floating litter (>1 cm) were greater and more variable in the Straits of Malacca (578±219 items km(-2)) than in oceanic waters of the Bay of Bengal (8.8±1.4 items km(-2)). The density of debris in the Straits was correlated with terrestrial vegetation, and peaked close to urban centres, indicating the predominance of land-based sources. In the Bay of Bengal, debris density increased north of 17°N mainly due to small fragments probably carried in run-off from the Ganges Delta. The low densities in the Bay of Bengal relative to model predictions may result from biofouling-induced sinking and wind-driven export of debris items. Standardised data collection protocols are needed for counts of floating debris, particularly as regards the size classes used, to facilitate comparisons among studies.
Mushroom industries generate a virtually in-exhaustible supply of a co-product called spent mushroom substrate (SMS). This is the unutilised substrate and the mushroom mycelium left after harvesting of mushrooms. As the mushroom industry is steadily growing, the volume of SMS generated annually is increasing. In recent years, the mushroom industry has faced challenges in storing and disposing the SMS. The obvious solution is to explore new applications of SMS. There has been considerable discussion recently about the potentials of using SMS for production of value-added products. One of them is production of lignocellulosic enzymes such as laccase, xylanase, lignin peroxidase, cellulase and hemicellulase. This paper reviews scientific research and practical applications of SMS as a readily available and cheap source of enzymes for bioremediation, animal feed and energy feedstock.
The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.