Diurnal Variation of the Water Quality Parameters in the Waste Stabilization Ponds (WSP) for Water Treatment of Integrated Multi-Trophic Aquaculture (IMTA) Ponds with Closed Re-Circulation System

Penulis: Nurul Setiadewi,Guruh Satria Ajie
Organic wastes from Floating Fish Cage Aquaculture (FCA) activities have polluted many inland water bodies, from small reservoirs to major lakes, in Indonesia. It has become a national priority to restore ecosystem health in Lake Maninjau. The lake has suffered from the negative effects of approx. 17,000 units of FCA on its surface area. Response for a better FCA practices that would process its own waste before returning it back to the lake ecosystem has been proposed. FCA waste should be contained for then pumped into a wetland system for its water quality improvement. The proposed system consists of a series of Waste Stabilization Ponds (WSP) and Constructed Wetland Compartments. For the initial stage, a study has been conducted to test the performance of the WSP to improve water quality from the Integrated Multi-Trophic Aquaculture (IMTA) ponds in the Prototype Laboratory of Research Centre for Limnology-LIPI. Two major problems in IMTA, namely organic deposition and low of dissolved oxygen (DO) especially concerning its diurnal variations in the system have not studied yet. Water qualities of the WSP ponds were measured every 2 hours for 3 days (22-25 May 2019) using Horriba© water quality checker and YSI© DO meter. Water quality parameters measured were pH, conductivity, dissolved oxygen (DO), turbidity, temperature, oxidation and reduction potential (ORP), and total dissolved solids (TDS). A closed recirculation within the WSP system was then applied for the last 2 days of the study periods. The results showed that DO values in the effluent pond during the day were significantly higher than the night. Within the maturation and facultative ponds DO values difference would ranging from 2.5-3 mg/L and 1.1-4.4 mg/L, respectively. The highest DO (5.98 mg/L) was measured in the maturation pond at third day afternoon (3.00 PM) and values were lowest near to 0 mg/L during the first day in the anaerobic ponds. While for turbidity, the highest was observed in the anaerobic ponds for 41 NTU and were decreased to stable values of an average of 5.3 NTU in the maturation pond on the third day. At end of the observation, significant increase of DO and decrease in turbidity have occurred in the system. A closed recirculation system within WSP can be used as an option to increase the performance of the wetland system. Keywords: diurnal variation, water quality, waste stabilization ponds, IMTA aquaculture

International Conference on Tropical Limnology, 2019, Vol.1

No. Arsip : LIPI-20200117