Carbon limitation of biomass production in high‐rate oxidation ponds

Abstract

Theoretical considerations confirmed by outdoor experiments indicated carbon limitation of biomass production in high-rate oxidation ponds at certain seasonal and operational conditions. Apparently, free carbon dioxide concentration in the pond is the major determinant of carbonlimiting algal photosynthesis. High concentrations of free CO(2) are provided through bacterial respiration which is the main contributor to algal photosynthesis. At high photosynthetic activities and low organic loadings, free CO(2) concentrations are low; its flux into algal cells determines photosynthesis and biomass production rate in the pond.

Influence of flue gas sparging on the performance of high rate algae ponds treating agro-industrial wastewaters

“…Despite irradiance only increases by 15% from periods 1 to 2, the effect of light intensity on microalgae growth might be substantial HRAP. However, this increase in biomass concentration in HRAP A was lower than the reported by Azov et al [16], who observed enhancements in biomass formation higher than 100% in a HRAP supplied with CO 2 . At this point it must be highlighted that this type of comparison are not always fair due to the different degree of carbon limitations in the system, different irradiance, etc.…”

Hectare-scale demonstration of high rate algal ponds for enhanced wastewater treatment and biofuel production

“…At a pond water pH of >8.5, the growth of both the wastewater algae and the aerobic heterotrophic bacteria (which degrade the wastewater organic compounds) is increasingly inhibited, in part as a result of high free ammonia concentrations (Azov et al 1982). Addition of CO 2 to wastewater treatment HRAPs (Fig.…”

Stabilization ponds: Design and operation

“…But at longer retention periods the carbon dioxide supply can become limiting. In this respect it is of interest that in work carried out in Israel 81 shallow ponds of 250 mm depth became rate limited by lack of carbon within 2 days, but in the slightly deeper ponds (350 mm) this only occurred after 3 days.…”