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-Water treatment technologies in the developing world typically focus on removing two types of impurities from water sources: suspended solids and microbial pathogens. However, as industrialization and high-input agriculture has expanded into the developing world, chemical impurities such as pesticides, herbicides, and fertilizers have found their way into drinking water supplies and have been linked to severe health-related issues. Activated carbon has the capacity to remove these problematic chemicals from water sources. A simple, inexpensive, and effective activated carbon production process using local agricultural waste byproducts was assessed for the community of Bluefields, Nicaragua. Coconut shell charcoal was produced on site, and various chemical activation techniques were investigated. The adsorption capacity of three separate chemically activated coconut shell charcoals was analyzed, with sodium chloride-common table salt-being the most efficient and cost effective activating agent.

The effect of feast/famine growth conditions on activated sludge cultures indicates that nonfilamentous cultures can be selected by providing proper substrate gradients and extended periods of endogenous metablism. Reactor operating strategies providing intermittently high substrate concentrations result in cultures characterized by high peak substrate and oxygen uptake activities, rapid settling rates, and high resistance to starvation. Sludge settleability can be manipulated using controlled variations in growth environment with corresponding changes noted in sludge activity. In combination with the low net growth rates associated with activated sludge systems, feast/famine environments would logically convey a selection advantage to microbes capable of readily assimilating substrate materials and maintaining viability during extended starvation periods.

No abstract

Intracellular carbon flow in enhanced biological phosphorus accumulating cultures was tracked by using radiolabelled glucose and acetate as substrates. Batch studies using the labelled substrates verified that acetate and glucose were metabolized differently and acetate would be a more effective source of organic material for carbon supplementation. The use of acetate ensures that the greatest percentage of added carbon will be sequestered by phosphorus accumulating species. Carbon flow was also evaluated in bench-scale SBR system by wet chemistry methods to correlate the findings of the batch studies with that of the long-term carbon profiles.