Novel Liquid Chitosan-Based Biocoagulant for Treatment Optimization of Fish Processing Wastewater from a Moroccan Plant

Abstract

A novel liquid chitosan-based biocoagulant for treating wastewater from a Moroccan fish processing plant was successfully prepared from shrimp shells (Parapenaeus longirostris), the most abundant fish by-products in the country. The shells were characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, and Fourier transforms infrared spectroscopy. Using chitosan without adding acetic acid helps to minimize its negative impact on the environment. At the same time, the recovery of marine shellfish represents a promising solution for the management of solid fish waste. In order to test the treatment efficiency of the biocoagulant developed, a qualitative characterization of these effluents was carried out beforehand. The optimization process was conducted in two steps: jar-test experiments and modeling of the experimental results. The first step covered the preliminary assessment to identify the most influential operational parameters (experimental conditions), whereas the second step concerned the study of the effects of three significant operational parameters and their interactions using a Box–Behnken experimental design. The variables involved were the concentration of coagulant (X1), the initial pH (X2), and the temperature (X3) of the wastewater samples, while the responses were the removal rates of turbidity (Y1) and BOD5 (Y2). The regression models and response surface contour plots revealed that chitosan as a liquid biocoagulant was effective in removing turbidity (98%) and BOD5 (53%) during the treatment. The optimal experimental conditions were found to be an alkaline media (pH = 10.5) and a biocoagulant dose of 5.5 mL in 0.5 L of fish processing wastewater maintained at 20 °C.

Shrimp Waste Upcycling: Unveiling the Potential of Polysaccharides, Proteins, Carotenoids, and Fatty Acids with Emphasis on Extraction Techniques and Bioactive Properties

“…Chitosan precipitates in alkaline solutions or with polyanions and forms a gel at lower pH. It also serves as a flocculant for wastewater treatment [65].…”

The Synergistic Effects of Al3+ and Chitosan on the Solid–Liquid Separation of Coal Wastewater and Their Mechanism of Action

“…The strong synergistic chelation of sulfhydryl, carboxyl, amide, and hydroxyl groups was mainly used for fine particles, while the branched structure promoted the formation of large and stable flocs through adsorption and the bridging–coiling effect. Currently, research on chitosan applications focuses on printing and dyeing wastewater [ 20 ], food industry wastewater [ 21 ], heavy metal wastewater [ 22 ], domestic wastewater [ 23 ], surface water treatment [ 24 ], sludge dewatering conditioning [ 25 , 26 ], and other fields. Color substances, chemical oxygen demand, proteins, oils, suspended solids, and algae in the water were removed [ 7 ].…”