We consider an optimal control problem involving the use of bacteria for pollution removal where the model assumes the bacteria switch instantaneously between active and dormant states, determined by threshold sensitivity to the local concentration v of a diffusing critical nutrient; compare [7], [3], [6] in which nutrient transport is convective. It is shown that the direct problem has a solut...

Biological Nutrient Removal (BNR) is critical for the preservation of our lakes and streams. Large amounts of waste products are passed through our sewage treatment systems on a continuous basis. Nutrient loads discharged from these systems must be reduced to avoid eutrophication of the receiving waters. Microbes are particularly useful in biodegrading most of the compounds treated by wastewate...

Litter-induced pulses of nutrient availability could play an important role in the productivity and nutrient cycling of forested ecosystems, especially tropical forests. Tropical forests experience such pulses as a result of wet-dry seasonality and during major climatic events, such as strong El Niños. We hypothesized that (1) an increase in the quantity and quality of litter inputs would stimu...

Plant communities in natural ecosystems are changing and species are being lost due to anthropogenic impacts including global warming and increasing nitrogen (N) deposition. We removed dominant species, combinations of species and entire functional types from Alaskan tussock tundra, in the presence and absence of fertilization, to examine the effects of non-random species loss on plant interact...

Article Type: Full Length Research Article The aim of this investigation was to confirm a trickling filter filled with gravel as an alternative biological process over conventional high cost treatment process with regard to nutrient reduction from brewery wastewater. Steady state evaluation of the trickling filter aerobic and anaerobic biofilm system for nutrient removal was made. The results o...

The treatment and disposal of excess sludge has been a rising challenge for wastewater treatment plants worldwide. In this study, simultaneous sludge reduction and nutrient removal was evaluated in laboratory scale sequencing batch reactors (SBRs). Two SBRs were operated alongside for a duration of 370d. One SBR was operated to achieve nutrient removal (control-SBR) at 10d solids retention time...

Open raceway ponds are cost-efficient for mass cultivation of microalgae compared with photobioreactors. Although low-cost options like wastewater as nutrient source is studied to overcome the commercialization threshold for biodiesel production from microalgae, a cost analysis on the use of wastewater and other incremental increases in productivity has not been elucidated. We determined the ef...

Short exposures of Bacillus spores to nutrient germinants can commit spores to germinate when germinants are removed or their binding to the spores' nutrient germinant receptors (GRs) is inhibited. Bacillus subtilis spores were exposed to germinants for various periods, followed by germinant removal to prevent further commitment. Release of spore dipicolinic acid (DPA) was then measured by diff...

Advanced nutrient removal processes, while improving the water quality of the receiving water body, can also produce indirect environmental and health impacts associated with increases in usage of energy, chemicals, and other material resources. The present study evaluated three levels of treatment for nutrient removal (N and P) using 27 representative treatment process configurations. Impacts ...