Investigation of nutrients and faecal coliforms removal in wastewater using a hydroponic system

Fresh water resources are diminishing rapidly through increased inadequately treated or untreated wastewater disposal in water bodies. Disposal of untreated wastewater in freshwater bodies threatens the environment, aquatic and human life. The primary objective of this study was to investigate the removal of contaminants using a simple cost effective hydroponic system in the treatment of raw wastewater to allowable discharge limits. After macrophytes were planted and water circulated in the hydroponic system the influent and effluent samples were collected at various time intervals between 24 and 244 h for the period of 3 months at varying concentrations. Ammonia, nitrite, nitrate and total phosphorus were measured using spectrophotometric methods and membrane filtration technique was used for faecal coliform counts. The removal of ammonia, nitrite, nitrate, total phosphorus and faecal coliforms reached 87%, 96%, 99%, 87% and 92% respectively. The paired t-test indicated the removal of these contaminants to be statistically significant (0.019 ≥ p ≥ 0.001). Irrespective of the change in wastewater composition the system efficiently treated water to allowable discharge limits. The system proved to be a cheaper method of wastewater treatment and its applications may offer an alternative to the problems of wastewater treatment in areas where modern systems are either unavailable or cost ineffective.