Mobile digital colorimetry for the determination of ammonia in aquaculture applications

Abstract

Because of the increasing need for healthy and safe foods, the interest for aquaculture is growing. This is a low carbon trace approach to produce animal protein, but the efficiency of a farm depends on controlling a set of parameters related to the quality of the water. One of the most important parameters to keep under control in water is the concentration of ammonia, which increases by the accumulation of fish excretions and the decomposition of leftover food. Determining the ammonia concentration in water often requires expensive equipment and experienced technicians, which is prohibitive for many aquaculture producers. We present a methodology to estimate the ammonia concentration of the water from an aquaculture pond. First, we prepare a water sample using a filter and three chemical reagents. The water sample acquires a coloration that is related to the concentration of ammonia in the water. Then, a mobile application is used to capture an image of the colored sample, which is subjected to a digital colorimetry procedure to estimate the ammonia concentration in the water sample. This approach requires inexpensive consumables, and the aquaculture producer requires little training to perform the measurements. Also, the mobile device is something that the aquaculture producer may already have. Even though the camera sensors in commercial mobile devices are far from being accurate measuring instruments, the tests conducted shown that our methodology can estimate the ammonia concentration in water with enough accuracy to determine when the water in the aquaculture pond needs to be replaced.