Purification effect of industrialized turtle-breeding wastewater using an improved celery ecological floating-bed system

Abstract

Abstract. Direct discharge of industrialized turtle-breeding wastewater may cause serious water pollution. This paper investigated the purification effect of industrialized turtle-breeding wastewater using an improved celery ecological floating-bed system with circulating water flow and intermittent aeration in the glass greenhouse. The results showed that the system with intermittent aeration had a removal efficiency of 99.5%, 98.2%, 88.6% and 84.6% for ammonia nitrogen (NH4+-N), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP), respectively. For circulating water flow, the removal efficiency was 97.2%, 95.5%, 73.9% and 74.9%, respectively. The accumulation of total phosphorus and total nitrogen in celery body for intermittent aeration were 0.2 and 1.03 mg·d-1 per plant, while 0.098 and 0.9 mg·d-1 per plant for circulating water flow. The purification rate of NH4+-N, COD, TN and TP was 0.98, 4.77, 0.996 and 0.094 mg· L-1·m-2·d-1 for intermittent aeration, and 0.21, 1.55, 0.29 and 0.031 mg·L-1·m-2·d-1 for circulating water flow, respectively. It was indicated that, for purifying industrialized turtle-breeding wastewater, the celery ecological floating-bed system was quite efficient and relatively inexpensive, and the intermittent aeration was better than circulating water flow and more energy saving.