Surfactants Obtained from Chemical Transformation of Waste Biomass

3 Surfactants Obtained from Chemical Transformation of Waste Biomass 

The idea of obtaining surfactant-like material from compost has been explored by the group of Montoneri at the University of Torino [43-45]. This group based their studies on the fact that humic acids (HAs) and related compounds in alkaline solutions are capable of reducing the surface tension of water, forming micelles and solubilizing hydrophobic compounds [46]. Most of the applications for HA-like surfactants are currently 

It is estimated that nearly 30 g of dry mixed sludge (from aerobic and anaerobic treatment) are produced per day per inhabitant [53] in municipal treatment systems alone. This suggests that for a city of 1 million inhabitants, this constitutes approximately 30 tonnes of dry sludge produced every day. Wastewater biosolids can be an important source of carbon-based compounds [54], The most important components of wastewater biomass are polysaccharides and proteins, either in pure form or in associations with other compounds, such as glycoproteins, lipopolysaccharides, lipoproteins, and so on. Other constituents include humic substances, deoxyribonucleic acid (DNA), lipids and uronic acids [54]. In the case of lipids, the content of lipids can vary from 2 to 30% [55]. 

The alkaline treatment is an effective analytical extraction technique for extracellular biopolymers from biomass, where NaOH is the most commonly used base. The increase in pH with alkaline addition induces the formation of anionic charges from carboxylic groups in proteins and polysaccharides, destabilizing the sludge floes. 

Alkaline treatment of wastewater sludge is currently used as a method to stabilize it (inactivate pathogens), to dissolve part of the organic carbon as a pre-treatment before anaerobic digestion and as a method to reduce its heavy metal content [52, 59-62]. In the 

---