Integrated algae pond systems (IAPS) combine the use of anaerobic and aerobic bioprocesses to effect sewage treatment. In the present work, the performance of IAPS was evaluated to determine the efficiency of this technology for treatment of municipal sewage under South African conditions. Composite samples were analysed over an 8 month period before and after tertiary treatment. Spectrophotometric assays indicated that the treated water from this IAPS was compliant with the discharge limits for phosphate-P, ammonium-N and nitrate/nitrite-N, and mean values were: 5.3, 2.9 and 12.4 mg L(-1), respectively. Chemical oxygen demand (COD), however, fluctuated significantly and was dependent on full function of the IAPS. Mean COD of the final treated water was 72.2 mg L(-1). Although these results suggest that the treated water discharged from this IAPS operating under South African conditions meets the standard for discharge, mean total suspended solids (TSS) was routinely above the limit at 34.5 ± 13 mg L(-1) and faecal coliforms were higher than expected. Tertiary treatment using a maturation pond series (MPS), slow sand filtration (SSF), or a controlled rock filter (CRF) ensured that the final treated water from the IAPS was of a quality suitable for discharge to the environment with CRF > SSF > MPS.

Integrated Algae Pond Systems (IAPS) are a derivation of the Oswald-designed Algal Integrated Wastewater Pond Systems (AIWPS®) and combine the use of anaerobic and aerobic bioprocesses to effect sewage treatment. IAPS technology was introduced to South Africa in 1996 and a pilot plant designed and commissioned at the Belmont Valley WWTW in Grahamstown. The system has been in continual use since implementation, and affords secondarily treated water for reclamation according to its design specifications, which most closely resemble those of the AIWPS Advanced Secondary Process. In this paper IAPS as a municipal sewage treatment technology is re-examined in relation to design and operation, the underpinning biochemistry of nutrient removal by algae is described, and a retrospective is provided on the demonstration system at the Belmont Valley WWTW. In addition to presenting details of the process flow, several shortcomings and/or oversights are highlighted and, in particular, the need for an appropriate tertiary treatment component. However, despite the use of IAPS for sewage treatment in many countries, this technology is still viewed with some scepticism. Thus, a major purpose of this overview is to provide a synthesis of available information on IAPS and an appraisal of its use for municipal sewage treatment.