Response Surface Methodology (RSM) Approach to Optimization of Coagulation-Flocculation of Aquaculture Wastewater Treatment Using Chitosan from Carapace of Giant Freshwater Prawn Macrobrachium rosenbergii

Abstract

The major sources of waste from aquaculture operations emanates from fish or shellfish processing and wastewater generation. A simple technique called coagulation/flocculation utilizes biowaste from aquaculture to produce chitosan coagulant for wastewater treatment. A chemical method was applied in the present study for chitin and chitosan extraction from carapace of Macrobrachium rosenbergii and subsequent application for removal of turbidity and salinity from shrimp aquaculture wastewater. Box-Behnken in RSM was used to determine the optimum operating conditions of chitosan dosage, pH, and settling time, after which quadratic models were developed and validated. Results show that 80 g of raw powder carapace yielded chitin and chitosan of 23.79% and 20.21%, respectively. The low moisture (0.38%) and ash (12.58%) content were an indication of good quality chitosan, while other properties such as water-binding capacity (WBC), fat-binding capacity (FBC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscope (SEM) confirmed the structure and the α-group, as well as the rough morphology of chitosan. In addition, the high solubility (71.23%) and DDA (85.20%) suggested good coagulant potentials. It was recorded in this study that 87.67% turbidity was successfully removed at 20 mg/L of chitosan dosage and 6.25 pH after 30 min settling time, while 21.43% salinity was removed at 5 mg/L of chitosan dosage, 7.5pH, and 30 min settling time. Therefore, the process conditions adopted in this study yielded chitosan of good quality, suitable as biopolymer coagulant for aquaculture wastewater treatment.

Physicochemical Properties of Chitosan from Green Mussel Shells (Perna viridis): A Comparative Study

“…Luo et al [5] and Kumari et al [7] reported a similar outcome for chitosan extracted from shrimp shells (246%), fish scales (226%), and grasshoppers (275%). However, the FBC values of both forms of extracted chitosan in this study were lower than those of chitosan from mealworm (574%), silkworm chrysalis (412%) [5], black tiger shrimp shells (397-428%) [17], and giant freshwater prawn (372.33%) [27]. The FBC value generally depends on the source of raw material and chitosan production [25].…”

Aquaculture from inland fish cultivation to wastewater treatment: a review

“…A study was conducted to treat aquaculture wastewater using bioflocculant, where the treatment managed to decrease the turbidity by 84% and remove suspended solids by 79% (Kurniawan et al 2022). Another study was conducted using a natural flocculant (chitosan) and was able to remove the turbidity by 87.7% (Iber et al 2023), which falls in the same range as the bioflocculant used in the previous study. However, when using organic poly aluminum chloride, a chemical coagulant, the removal efficiency of turbidity, TSS, and phosphorus was over 97% (Heiderscheidt et al 2020).…”

Preparation and Application of Fe-Al-SiO2 Poly-Coagulants for Removing Microcystis aeruginosa from Water

“…Box-Behnken design (BBD) of the RSM of the Design-Expert 12 software (State-Ease, USA) was utilized to investigate the relationship between the input variables and the output responses, obtain the fitted model, and generate optimal operating conditions of FAS poly-coagulants for algae removal [22,46]. In this study, the three input variables chosen were n(Fe):n(Al), m(Si):m(Al+Fe), and n(CO 3 2− ):n(Al+Fe).…”