Biomass aquatic plants

An alternative method of produciag hydrocarbon fuels from biomass uses oils that are produced ia certaia plant seeds, such as rape seed, sunflowers, or oil palms, or from aquatic plants (see Soybeans and other oilseeds). Certain aquatic plants produce oils that can be extracted and upgraded to produce diesel fuel. The primary processiag requirement is to isolate the hydrocarbon portion of the carbon chain that closely matches diesel fuel and modify its combustion characteristics by chemical processiag. 

Current reviews on biosorption are related to general approaches90-93 to diverse types of biomass such as microbial biomass, plant wastes, and agro-based waste materials, or to a specific metal.4-94-98 However, a review on metal biosorption using macrophytes biomass is not available. In this chapter, a review on the current knowledge of biosorption using preferentially nonliving biomass from aquatic plants is presented. 

Recent reports on biosorbents based on diverse types of macrophytes are found widely in the literature. Free-floating aquatic plants from the genera Salvinia, Azolla, Eichhornia, Lemna, and Pistia have been described the most. S. natans biomass was able to uptake As(V) at low initial concentrations from 0.25 to 2 mg/L (74.8% and 54%, respectively). The experimental data fitted well to both Langmuir and Freundlich isotherms. The effect of pH and biomass quantities on sorption rate has also been investigated along with some metabolic parameters.105... 

The list of plants, by-products and waste materials that can potentially be used as feedstock is almost endless. Major resources in biomass include agricultural crops and their waste by-products, lignocellulosic products such as wood and wood waste, waste from food processing and aquatic plants and algae and effluents produced in the human habitat. Moderately dried wastes such as wood residue, wood scrap and urban garbage can be directly burned as fuel. Energy from water-containing biomass... 

Raw material for biomass fuel can come from various sources such as wood, legumes, grains, sugar crops, animal waste, municipal waste, aquatic plants, and food and cotton production waste. TABLE 12-2 provides examples of biomass raw materials. 

Such conversion of Ci into organics can occur either under natural conditions-that is, via the uptake of C02 from the atmosphere, where it reaches a concentration equal to 0.038% (v/v)-or under enhanced or industrial conditions, that are much different from natural conditions. Typical examples of the enhanced biological fixation are (i) the cultivation of terrestrial biomass (ornamental plants, some vegetables) in greenhouses under a C02 concentration in the gas phase of approximately 600 ppm and (ii) the farming of aquatic biomass by dissolving C02 in water or under a gas-phase concentration up to 5-10%-that is, 130- to 260-fold the natural concentration. 

Biomass A range of phytotoxic and growth inhibitory effects have been attributed to surfactants (1). Increased lag phase growth was observed in Chlamydomonas and Chlorella attributable to > 1 yg/ml nonylphenol (20), 5 yg/ml Aerotex (10) > 7.5 yg/ml Cyclosol (17). No population growth effects were observed with Atlox or 585 oil < 30 yg/ml, or Dowanol < 1000 yg/ml. Both in the algal cells and in a range of aquatic plants initially exposed to surfactants and observed over a period of 21 days, a depressed biomass was coincident with increasing adjuvant concentrations. 

Coal is a sediment that consists of the remains of plants that have been buried, compressed, and dehydrated over time. Coal varies widely in composition and often contains clay or silt, but it is usually composed of at least 75% carbonaceous material. It is theorized that most coal formed in ancient swamps, where there was a huge biomass of plant material. Dead plants falling into an anaerobic, aquatic environment does not rot but accumulates in layers, sometimes for millions of years. 

The complex structure and seasonal dynamics of herbaceous macrophyte communities make it difficult to estimate their total annual contribution to floodplain lake production. Annual production estimates must incorporate the cumulative, sequential production of terrestrial, semiaquatic and aquatic plant communities and the spatial and temporal variation in their distributions. To date all measurements of macrophyte production have been made in a limited area on the central Amazon floodplain near Manaus. Only a few of these estimates have included contributions of more than one species. Junk and Piedade (1993) estimated the cumulative biomass increase of three successive macrophyte communities (terrestrial, semiaquatic, and aquatic) growing under... 

Aquatic biomass Freshwater plants Marine plants Microalgae... 

A recent literature review [13] listed 17 wetland plants capable of RDX removal from water, or removal accompanied by RDX incorporation into plant biomass. The emergent wetland plant Phalaris arundinacea (reed canary grass) and the submerged wetland plant Elodea canadensis were particularly suitable for RDX bioremediation using constructed wetlands in terms of RDX removal efficiency and relative persistence [39], Studies with the model aquatic plant M. aquaticum demonstrated that RDX removal from water was a first-order rate process, similar to TNT removal [14,43], However, the first-order rate constants for RDX removal were 3.0 x 10-5 L g 1 FW h 1 versus 2.2 x 10 3 L g 1 FW h 1 for TNT removal at the same conditions [14],... 

At present, the ability of aquatic vascular plants to remove HMX from water has not been conclusively established. Preliminary experiments performed by Bhadra et al. [43] suggested that the vascular aquatic plant M. aquaticum did not take up or biotransform HMX, whereas root cultures of the terrestrial vascular plant C. roseus removed HMX from water inefficiently, as the removal rate was only slightly higher than those for the biomass-free and heat-killed biomass controls. 

It is not possible, at present, to provide either a detailed resource base assessment (e.g., potentially available water, land, or nutrient resources), or a detailed cost analysis of aquatic plant production. Thus, this review presents general concepts of aquatic biomass farming exemplified by three systems — microalgae farming for lipid fuel and chemicals production, cattail cultivation for conversion to alcohol fuels, and growing water hyacinths for methane gas generation. Wastewater aquaculture applications are not covered in this review nor are the actual conversion processes by which aquatic biomass would be converted to fuels. 

---