R.K. TRIVEDY AND SONIA THOMAS
Abstract
Performance data of 3 water hyacinth based and four emergent plant species based wastewater treatment plants in India is reviewed in the present paper. Water hyacinth based systems were employed for treatment of sewage and industrial wastes. All the three systems are full-scale plants. The performance of hyacinth based systems was good despite poor designing and vegetation management especially with regard to reduction in BOD, COD and total nitrogen. Reduction in solids was not good in ail the systems. Considerable variations in performance was noticed which is attributed to different hyacinth coverage maintained and also the seasonal influences besides the level of housekeeping. The emergent plants based system (out of 4, one was a full scale plant and remaining three experimental level pilot systems) were found to be very efficient in BOD, COD and phosphorus removal but poor in nitrogen and solids reduction. The performance of these systems, however, gives very encouraging signals and more research is urgently needed on these systems especially with regard to system design and choice of plant species.