Biomass

In the last century, biomass fuels - mostly wood - provided most of the world's energy. Today biomass in all its forms (wood, dung, and agricultural and forest residues) supplies about 14 percent of our energy - most of it in developing countries, where biomass is the most common energy source. Biomass provides more than a quarter of China's energy, for example. Rural areas in most developing countries depend heavily on biomass for energy. A dearth of biomass energy usually indicates other developmental and environmental problems. The difficulty in trying to ameliorate such problems is that bioenergy may not be a priority for local communities,which have more pressing problems or are unable to take the longer-term view toward rehabilitating their biomass resources. But outside energy experts tend to focus on one aspect of biomass use to the exclusion of all others, and therefore many biomass energy projects and programs fail. The author presents case studies showing that local involvement and control is a prerequisite for the success of such programs. There is an enormous untapped potential for biomass, and bioenergy systems may be less irreversibly damaging to the environment than conventional fossil fuels. Bioenergy systems produce many but mostly local and relatively small impacts on the environment and their impact is more controllable. There is no short-cut, however, to long-term planning and development of biomass energy systems. And the barriers are many: economic, social, and technological. Modernizing biomass technologies, for example - so biomass can be used for liquid fuel, electricity, and gas (in addition to its traditional use as a heat source) - involves land use issues that make implementation of biomass projects more difficult than projects involving more centralized energy resources. But both traditional and modernizied biomass energy systems need developing to produce preferred forms such as heat, electricity, and liquids. Biomass energy should be modernized more rapidly, and at the same time traditional biomass fuels should be produced and used as efficiently as possible - both in a sustainable manner.Sanitation and Sewerage,TF030632-DANISH CTF - FY05 (DAC PART COUNTRIES GNP PER CAPITA BELOW USD 2,500/AL,Energy and Environment,Montreal Protocol,Climate Change

A New General Allometric Biomass Model

To implement monitoring and assessment of national forest biomass, it is becoming the trend to develop generalized single-tree biomass models suitable for large scale forest biomass estimation. Considering that the theoretical biomass allometric model developed by West et al. [1,2] was statistically different from the empirical one, the two parameters in the most commonly used biomass equation M=aDb were analyzed in this paper. Firstly, based on the knowledge of geometry, the theoretical value of parameter b was deduced, i.e., b=7/3(~2.33), and the comparison with many empirical studies conducted throughout the globe indicated that the theoretical parameter could describe soundly the average allometric relationship between aboveground biomass M and D (diameter on breast height). Secondly, using five datasets of aboveground biomass which consisted of 1441 M-D pairs of sample trees, the new general biomass allometric model was validated. Finally, the relationship between parameter a and wood density p was analyzed, and the linear regression was developed. The new model, which is not only simple but also species-specific, offers a feasible approach on establishment of generalized biomass models for regional and national forest biomass estimation

Pretreatment Processes of Biomass for Biorefineries: Current Status and Prospects

Producción CientíficaThis article seeks to be a handy document for the academy and the industry to get quickly up to speed on the current status and prospects of biomass pretreatment for biorefineries. It is divided into two biomass sources: vegetal and animal. Vegetal biomass is the material produced by plants on land or in water (algae), consuming sunlight, CO2, water, and soil nutrients. This includes residues or main products from, for example, intensive grass crops, forestry, and industrial and agricultural activities. Animal biomass is the residual biomass generated from the production of food from animals (e.g., manure and whey). This review does not mean to include every technology in the area, but it does evaluate physical pretreatments, microwave-assisted extraction, and water treatments for vegetal biomass. A general review is given for animal biomass based in physical, chemical, and biological pretreatments

Microalgae recycling improves biomass recovery from wastewater treatment high rate algal ponds

Microalgal biomass harvesting by inducing spontaneous flocculation (bioflocculation) sets an attractive approach, since neither chemicals nor energy are needed. Indeed, bioflocculation may be promoted by recycling part of the harvested microalgal biomass to the photobioreactor in order to increase the predominance of rapidly settling microalgae species. The aim of the present study was to improve the recovery of microalgal biomass produced in wastewater treatment high rate algal ponds (HRAPs) by recycling part of the harvested microalgal biomass. The recirculation of 2% and 10% (dry weight) of the HRAPs microalgal biomass was tested over one year in an experimental HRAP treating real urban wastewater. Results indicated that biomass recycling had a positive effect on the harvesting efficiency, obtaining higher biomass recovery in the HRAP with recycling (R-HRAP) (92–94%) than in the control HRAP without recycling (C-HRAP) (75–89%). Microalgal biomass production was similar in both systems, ranging between 3.3 and 25.8 g TSS/m2d, depending on the weather conditions. Concerning the microalgae species, Chlorella sp. was dominant overall the experimental period in both HRAPs (abundance >60%). However, when the recycling rate was increased to 10%, Chlorella sp. dominance decreased from 97.6 to 88.1%; while increasing the abundance of rapidly settling species such as Stigeoclonium sp. (16.8%, only present in the HRAP with biomass recycling) and diatoms (from 0.7 to 7.3%). Concerning the secondary treatment of the HRAPs, high removals of COD (80%) and N-NH4+ (97%) were found in both HRAPs. Moreover, by increasing the biomass recovery in the R-HRAP the effluent total suspended solids (TSS) concentration was decreased to less than 35 mg/L, meeting effluent quality requirements for discharge. This study shows that microalgal biomass recycling (10% dry weight) increases biomass recovery up to 94% by selecting the most rapidly settling microalgae species without compromising the biomass production and improving the wastewater treatment in terms of TSS removal.Peer ReviewedPostprint (author's final draft

Modeling Compatible Single-Tree Aboveground Biomass Equations of Masson Pine (Pinus massoniana) in South China

In the background of facing up to the global climate change, it is becoming the inevitable demand to add forest biomass estimation to national forest resource monitoring. The biomass equations to be developed for forest biomass estimation should be compatible with volume equations. Based on the tree volume and aboveground biomass data of Masson pine (Pinus Massoniana Lamb.) in south China, the one, two and three-variable aboveground biomass equations and biomass conversion functions compatible with tree volume equations were constructed using the error-in-variable simultaneous equations in this paper. The results showed: (i) the prediction precision of aboveground biomass estimates from one variable equation was more than 95%; (ii) the regressions of aboveground biomass equations improved slightly when tree height and crown width were used together with diameter on breast height, although the contributions to regressions were statistically significant; (iii) for biomass conversion function on one variable, the conversion factor was decreased with growing diameter, but for conversion function on two variables, the factor was increased with growing diameter while decreased with growing tree height

Effects of nutrient enrichment on seagrass population dynamics: evidence and synthesis from the biomass-density relationships

The available data from experimental and descriptive studies on seagrass biomass and density responses to nutrient enrichment were analysed to assess the intraspecific mechanisms operating within seagrass populations and whether biomass-density relationships can provide relevant metrics for monitoring seagrasses. The response of shoot biomass and density to nutrient enrichment was dependent on the type of study; the short-term positive response of biomass and density in experimental studies reveals context-specific nutrient limitation of seagrasses. The long-term negative response of descriptive studies probably results from ecosystem-scale events related to nutrient enrichment such as increased turbidity, algal blooms, epiphyte loads and anoxia. Most seagrass species analysed lie in the nonthinning part of the theoretical biomass-density curves. A simultaneous increase in biomass and decrease in density, evidence of self-thinning, were only observed in 4 of 28 studies. The analysis of both the static and the dynamic biomass-density relationships revealed that the slopes increase under nutrient enrichment. Surprisingly, the species-specific slopes (log B-log D) were higher than one, revealing that the B/D ratio, that is, the average shoot biomass, increases with density in all seagrass species analysed. Nutrient enrichment further enhanced this effect as biomass-density slopes increased to even higher values. The main drivers behind the increasing biomass-density slopes under nutrient enrichment were the increase in shoot biomass at densities above a species-specific threshold and/or its decrease below that threshold. Synthesis. Contrasting short- and long-term responses of both biomass and density of seagrasses to nutrient enrichment suggest that the former, positive ones result from nutrient limitation, whereas the later, negative ones are mediated by whole ecosystem responses. In general, shoot biomass of seagrasses increases with density, and nutrient enrichment enhances this effect. Experimental testing of facilitation processes related to clonal integration in seagrasses needs to be done to reveal whether they determine the low incidence of self-thinning and the intriguing biomass-density relationships of seagrass species. The increasing slopes and decreasing intercepts of the species-specific dynamic biomass-density relationships of seagrasses and the decreasing coefficients of variation of both biomass and density constitute relevant, easy-to-collect metrics that may be used in environmental monitoring.EU project ECO-LAGUNES [SOE1/P2/F153]; COST Action [ES0906]; FCT [SFRH/BPD/37368/2007, SFRH/BPD/75307/2010]; NSERC PGSD; Killam Trustinfo:eu-repo/semantics/publishedVersio

Logistics issues of biomass : the storage problem and the multi-biomass supply chain

Biomass is a renewable energy source with increasing importance. The larger fraction of cost in biomass energy generation originates from the logistics operations. A major issue concerning biomass logistics is its storage, especially when it is characterized by seasonal availability. The biomass energy exploitation literature has rarely investigated the issue of biomass storage. Rather, researchers usually choose arbitrarily the lowest cost storage method available, ignoring the effects this choice may have on the total system efficiency. In this work, the three most frequently used biomass storage methods are analyzed and are applied to a case study to come up with tangible comparative results. Furthermore, the issue of combining multiple biomass supply chains, aiming at reducing the storage space requirements, is introduced. An application of this innovative concept is also performed for the case study examined. The most important results of the case study are that the lowest cost storage method indeed constitutes the system-wide most efficient solution, and that the multi-biomass approach is more advantageous when combined with relatively expensive storage methods. However, low cost biomass storage methods bear increased health, safety and technological risks that should always be taken into account. (C) 2008 Elsevier Ltd. All rights reserved