Harmful non-indigenous species (NIS) impose great economic and environmental impacts globally, but little is known about their impacts in Southeast Asia. Lack of knowledge of the magnitude of the ...problem hinders the allocation of appropriate resources for NIS prevention and management. We used benefit-cost analysis embedded in a Monte-Carlo simulation model and analysed economic and environmental impacts of NIS in the region to estimate the total burden of NIS in Southeast Asia. The total annual loss caused by NIS to agriculture, human health and the environment in Southeast Asia is estimated to be US$33.5 billion (5(th) and 95(th) percentile US$25.8-39.8 billion). Losses and costs to the agricultural sector are estimated to be nearly 90% of the total (US$23.4-33.9 billion), while the annual costs associated with human health and the environment are US$1.85 billion (US$1.4-2.5 billion) and US$2.1 billion (US$0.9-3.3 billion), respectively, although these estimates are based on conservative assumptions. We demonstrate that the economic and environmental impacts of NIS in low and middle-income regions can be considerable and that further measures, such as the adoption of regional risk assessment protocols to inform decisions on prevention and control of NIS in Southeast Asia, could be beneficial.
The increasing world population necessitates the production of larger amounts of food in a safe and environmentally sustainable manner, while concomitantly managing an increasing amount of food waste ...similarly. These needs can theoretically be met by the recycling of the nutrients in food waste via anaerobic digestion, which also produces renewable energy. This hypothesis is proven by the growing of a commonly consumed leafy vegetable, xiao bai cai (Brassica rapa), by the addition of food waste anaerobic digestate in place of commercial fertilizer. Different concentrations of the digestate were tested, as well as different heat treatments to simulate hygienization, and the results for most part (aerial fresh weight, dry weight, chlorophyll content) are not significantly different from growth utilizing commercial inorganic 15:15:15 NPK fertilizer. Microbial analysis of the growth media was also carried out to explicate digestate effects and to show that some common foodborne disease pathogens were not detected.
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•The increasing global population requires more food, food waste management and energy.•Food waste was anaerobically digested to produce energy and nutrient-rich digestate.•Digestate was used, including hygienization, to grow a commonly consumed green leafy vegetable, xiao bai cai, successfully.•The digestate was able to replace commercial fertilizer to achieve comparable aerial fresh and dry weight and increased chlorophyll index.•Anaerobic digestion can be used to manage food waste, produce biogas and to grow food.
Biochar industry to circular economy Hu, Qiang; Jung, Janelle; Chen, Dexiang ...
The Science of the total environment,
02/2021, Letnik:
757
Journal Article
Recenzirano
Biochar, produced as a by-product of pyrolysis/gasification of waste biomass, shows great potential to reduce the environment impact, address the climate change issue, and establish a circular ...economy model. Despite the promising outlook, the research on the benefits of biochar remains highly debated. This has been attributed to the heterogeneity of biochar itself, with its inherent physical, chemical and biological properties highly influenced by production variables such as feedstock types and treating conditions. Hence, to enable meaningful comparison of results, establishment of an agreed international standard to govern the production of biochar for specific uses is necessary. In this study, we analyzed four key uses of biochar: 1) in agriculture and horticulture, 2) as construction material, 3) as activated carbon, and 4) in anaerobic digestion. Then the guidelines for the properties of biochar, especially for the concentrations of toxic heavy metals, for its environmental friendly application were proposed in the context of Singapore. The international status of the biochar industry code of practice, feedback from Singapore local industry and government agencies, as well as future perspectives for the biochar industry were explained.
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•Waste to biochar is a sustainable partway to circular economy.•Four key uses of the Singapore biochar industry are analyzed and reviewed.•The code of practice for biochar application in Singapore is proposed.•Future perspective of the research, innovation and development for biochar industry is discussed.
Natural habitats remain on the decline worldwide, while extinction risks have not yet been formally assessed for the majority of plant species. This is of pressing concern in especially biodiverse ...regions where there are hotspots of species richness and endemism which are also under intense development. Borneo is the largest land mass of the Sundaland biodiversity hotspot and has rich and unique biodiversity. About one-third of Borneo’s plant species are endemic and known from nowhere else in the world. Conservation exigencies are examined for a subset of these species which are of its 65 endemic genera. Preliminary conservation assessments are made under the IUCN Red List Criterion B. Areas of remaining forest cover, which could be prioritised to protect as many species of endemic genera as possible, are highlighted and examined against existing protected areas (PAs). More than two-thirds of the species of endemic genera are assessed as Endangered or Critically Endangered, and although existing PAs account for about the same number of species, they cover only a small proportion of individual species distributions. As large-scale population extinctions are the forerunner of species extinctions, this is of deep concern. Hotspots of species richness are indicated in forests at low- to mid-elevation, especially in northwest Borneo, but these areas are now mostly in logged or severely logged forests outside of existing PAs. The distributions and species richness patterns of the endemic genera highlight the conservation exigencies for lowland forest habitats in Borneo, which additional remedial conservation measures must now heed.
AIM: Mangroves are intertidal plants with sea‐dispersed propagules, hence their population structure can offer valuable insights into the biogeographical processes driving population subdivision in ...coastal species. In this study, we used molecular markers and ocean circulation simulations to examine the effects of ocean currents and land masses on the genetic structure of the major mangrove species Rhizophora mucronata. LOCATION: Southeast Asia. METHODS: We assessed the genetic structure of 13 R. mucronata populations from continental Southeast Asia and Sumatra using 10 microsatellite loci. We first examined the relative effects of geographical distance and land mass (the Malay Peninsula) in shaping the genetic structure of R. mucronata in Southeast Asia. We then characterized the genetic structure of R. mucronata and compared it to the simulated ocean circulation patterns within our study region. RESULTS: Despite the low genetic diversity, significant genetic structuring was detected across R. mucronata populations. Contrary to observations on other mangrove species, genetic differentiation in R. mucronata was not found across the coasts of the Malay Peninsula, nor was it correlated with geographical distance. Instead, the most distinct genetic discontinuity was found at the boundary between the Andaman Sea and the Malacca Strait, and this can be explained by the prevailing ocean currents in this region. MAIN CONCLUSIONS: Our study presents novel evidence that the genetic structure of R. mucronata is maintained by ocean current‐facilitated propagule dispersal.
With possible food crises looming in the near future, urban farming, including small-scale community and home gardens for home consumption, presents a promising option to improve food security in ...cities. These small-scale farms and gardens often use planter boxes and raised beds filled with lightweight soil or potting mixes. While previous studies on biochar focused on its application on large-scale contiguous farmlands, this study aimed to evaluate the suitability of biochar as a partial soil substitute to produce a durable and lightweight soil-biochar mix for small-scale urban farms. The effects of biochar on the chemical properties of the soil-biochar mix, crop yield and, particularly, crop nutrients and metabolic content were assessed. A germination test using pak choi seeds (Brassica rapa L. cultivar group Pak choi, Green-Petioled Form) showed that the biochar contained phytostimulants. Through a nursery pot experiment over four growth cycles, biochar treatments performed better than pure soil at retaining water-soluble NO3− and K+ ions, but were worse at retaining PO43− ions. Nonetheless, despite its positive effect on soil NO3− retention, biochar application did not improve crop yield significantly when the application rate varied from 0% to 60% (v/v). Untargeted metabolomic analyses showed that biochar application may increase the production of carbohydrates and certain flavonoids and glucosinolates. The results of this study showed that biochar can potentially be used to improve pak choi nutritional values and applied in large quantity to obtain a lightweight soil mix for urban farming.
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•Biochar application improved soil nitrate and potassium retention but not phosphate.•Biochar application had null effects on pak choi biomass accumulation.•Biochar application increased carbohydrates but reduced amimo acids in pak choi.•Biochar application increased glucosinolates and flavonoids production in pak choi.
•Raw food-waste digestate and digestate-biochar residue tested as fertilizer.•Digestate at 20–40% application rates performed similarly to mineral fertilizer.•Digestate likely induced stress response ...in all 4 vegetables at concentrations >40%.•Digestate application increased the relative abundance of Synergistetes.•Digestate-biochar residue generally performed similarly to mineral fertilizer.
Anaerobic digestion produces large quantities of digestate as a by-product, which can potentially be applied as an organic fertilizer, but untreated anaerobic digestate (AD) may contain phytotoxins and the large volume of AD makes transportation and storage difficult. This study explored two relatively inexpensive processing methods to improve the agronomic performance of AD as a fertilizer via vegetable cultivation experiments. We first investigated the effect of dilution on AD’s performance using four leafy vegetables (Chinese spinach, water spinach, Chinese cabbage and lettuce). The optimal concentrations of the AD were 20–40% (v/v in 250 mL applications per single-plant pot) for all four vegetables based on shoot fresh weight and comparable to the control treatment using commercial fertilizer. AD application also introduced Synergistetes bacteria into the growing medium, but the overall bacterial diversity and composition were similar to those of the control treatment. Considering the nutrient separation in the liquid and solid fractions of AD and the need to reduce the volume, we then experimented with the recovery of nutrients from both the liquid and solid fractions by filtering AD using two types of wood-based biochar (100 g biochar: 1 L AD) before applying the AD-biochar residues as side dressing at 1% (w/w). Both types of biochar achieved yields comparable to the treatment using a commercial fertilizer for the three vegetables tested (kale, lettuce and rocket salad). Our results show that dilution and biochar filtration can improve the agronomic performance of AD, making it a sustainable substitute for commercial fertilizer.
Gasification is recognized as a green technology as it can harness energy from biomass in the form of syngas without causing severe environmental impacts, yet producing valuable solid residues that ...can be utilized in other applications. In this study, the feasibility of co-gasification of woody biomass and food waste in different proportions was investigated using a fixed-bed downdraft gasifier. Subsequently, the capability of biochar derived from gasification of woody biomass in the rehabilitation of soil from tropical secondary forests on degraded land (adinandra belukar) was also explored through a water spinach cultivation study using soil-biochar mixtures of different ratios. Gasification of a 60:40 wood waste-food waste mixture (w/w) produced syngas with the highest lower heating value (LHV) 5.29 MJ/m3—approximately 0.4–4.0% higher than gasification of 70:30 or 80:20 mixtures, or pure wood waste. Meanwhile, water spinach cultivated in a 2:1 soil-biochar mixture exhibited the best growth performance in terms of height (a 4-fold increment), weight (a 10-fold increment) and leaf surface area (a 5-fold increment) after 8 weeks of cultivation, owing to the high porosity, surface area, nutrient content and alkalinity of biochar. It is concluded that gasification may be an alternative technology to food waste disposal through co-gasification with woody biomass, and that gasification derived biochar is suitable for use as an amendment for the nutrient-poor, acidic soil of adinandra belukar.
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•Co-gasification of wood waste and food waste in different ratios was investigated.•Increasing the food waste proportion increases the heating value of the syngas.•Biochar was able to rehabilitate nutrient-poor and acidic soil from degraded land.•Water spinach cultivated in a 2:1 soil-biochar mixture grew best.
The increasing amount of food waste and the excessive use of mineral fertilizers have caused detrimental impacts on soil, water, and air quality. Though digestate derived from food waste has been ...reported to partially replace fertilizer, its efficiency requires further improvement. In this study, the effects of digestate-encapsulated biochar were comprehensively investigated based on growth of an ornamental plant, soil characteristics, nutrient leaching and soil microbiome. Results showed that except for biochar, the tested fertilizers and soil additives, i.e., digestate, compost, commercial fertilizer, digestate-encapsulated biochar had positive effects on plants. Especially, the digestate-encapsulated biochar had the best effectiveness as evidenced by 9–25% increase in chlorophyll content index, fresh weight, leaf area and blossom frequency. For the effects of fertilizers or soil additives on soil characteristics and nutrient retention, the digestate-encapsulated biochar leached least N-nutrients (<8%), while the compost, digestate and mineral fertilizer leached up to 25% N-nutrients. All the treatments had minimal effects on the soil properties of pH and electrical conductivity. According to the microbial analysis, the digestate-encapsulated biochar has the comparable role with compost in improving the soil immune system against pathogen infection. The metagenomics coupling with qPCR analysis suggested that digestate-encapsulated biochar boosted the nitrification process and inhibited the denitrification process. This study provides an extensive understanding into the impacts of the digestate-encapsulated biochar on an ornamental plant and offers practical implications for the choice of sustainable fertilizers or soil additives and food-waste digestate management.
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•Digestate-encapsulated biochar showed the best effectiveness on plants.•Digestate-encapsulated biochar retained the most nutrient in soil.•Digestate-encapsulated biochar boosted the nitrification process.•Digestate-encapsulated biochar inhibited the denitrification process.