Development of Lahar Filtration System for Recirculating Aquaculture System

 Rossana Marie C. Amongo¹, Arsenio N. Resurreccion², Victor B. Ella², Pepito M. Bato³, Fernando O. Paras Jr⁴, Omar F. Zubia⁴ and Edgardo V. Casas⁵

 ABSTRACT

The study aimed to develop a low-cost and efficient lahar filtration system for recirculating aquaculture system. The filtration system was composed of the settling tank, the mechanical filter and the biological filter with lahar as filter media. The system was attached to a culture tank with Tilapia (Oreochromis niloticus) as fish culture and its efficiency was determined using the Box and Behnken three level-incomplete factorial design.

Fifteen experimental runs were conducted to determine the system efficiency. Results showed that as the wastewater moved from the settling tank to the biological filter, decrease in TDS (1.82%), TSS (79.17%), NH3 (71.68%) and NO2 (61.08%) were observed. On the other hand, temperature (0.44%), pH (3%), DO (44.35%) and nitrate concentration (34.46%) were increased. Except for NH3, which was significantly affected by % feeding rate, the recirculated water to the culture tank met the permissible water quality limits for culturing tilapia. The cost effectiveness of the system was determined with a payback period of 2.33 years, breakeven point of 1.31 cropping per year, benefit cost ratio of 1.06 and internal rate of return of 39.02 % which showed its financial viability.

Keywords: lahar filtration system, culture tank, settling tank, mechanical filter, biological filter, wastewater, Recirculating Aquaculture System (RAS)

 

¹Assistant Professor, ^2,3,4,5Professors, Associate Professor, Assistant Professors and University Researcher, respectively, Institute of Agricultural Engineering, College of Engineering & Agro-Industrial Technology, University of the Philippines Los Baños, Philippines.