Coagulation of Chitin Production Wastewater from Shrimp Scraps with By-Product Chitosan and Chemical Coagulants

Abstract

Chitin production wastewater contains nutrient-rich organic and mineral contents. Coagulation of the wastewater with a natural coagulant such as by-product chitosan would be an economical and environmentally friendly method of treatment. This study investigated the treatment efficiencies of a preliminary sedimentation process followed by coagulation. The removal efficiencies for wastewater parameters were evaluated and compared for coagulants including by-product chitosan, polyaluminum chloride, and polyacryamide. The evaluation was based on the removal of wastewater turbidity and other criteria, including tCOD, sCOD, TKN, NH4+–N, TP, TSS, calcium, and crude protein. The results showed that the preliminary sedimentation (before coagulation) can remove over 80% of turbidity and more than 93% of TSS at pH 4 in 30 min. At optimal conditions, when the ratio of crude protein and calcium was 4.95, by-product chitosan dose of 77.5 mg·L−1 and pH = 8.3, the wastewater characteristics changes were tCOD 23%, sCOD 32%, TKN and ammonium 25%, TP 90%, TSS 84%, Ca2+ 29%, and crude protein 25%. The residue recovered through coagulation consists of up to 55 mg·g−1 crude protein, which is used for animal feed or crop fertilizer.

Recent Achievements in Polymer Bio-Based Flocculants for Water Treatment

“…Chitosan is proposed to coagulate pollutants in wastewater generated in the production of chitin. Tran’s idea [ 93 ] was a two-step process: initial sedimentation at pH range 4–11 (during which turbidity was already reduced by 80%), followed by coagulation with chitosan (total removing turbidity 99.4% at pH 10.6 and dose of 86.4 mg/L). It is worth emphasizing that the residue recovered by coagulation is rich in protein (55 mg/g) and can be used as supplement in animal feed or plant fertilizer.…”

Production and Potential Applications of Bioconversion of Chitin and Protein-Containing Fishery Byproducts into Prodigiosin: A Review

“…Chitin and its derivatives have numerous applications in the fields of environment protection, fine chemistry, and pharmacy [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ]. Fishery processing byproducts, such as shrimp and crab shells, shrimp heads, and squid pens, are the main sources of chitin and chitosan which are conventionally prepared via chemical pretreatments of acid demineralization and hot-alkali deproteinization [ 1 , 5 , 9 , 11 , 12 , 13 , 14 , 15 , 16 ]. Chitin, chitosan, colloidal chitin, and water soluble chitosan have commonly been used as the major carbon/nitrogen (C/N) sources for the isolation of strains producing chitinolytic enzymes and the production of chitinolytic enzymes by these isolated strains [ 9 , 15 , 16 , 17 , 18 ].…”

Bioprocessing of Squid Pens Waste into Chitosanase by Paenibacillus sp. TKU047 and Its Application in Low-Molecular Weight Chitosan Oligosaccharides Production

“…The optimal pH for Paenibacillus sp. TKU047 chitosanase activity was determined by adding the enzyme into substrate solutions at different pH (3)(4)(5)(6)(7)(8)(9)(10)(11). The pH stability of the enzyme of Paenibacillus sp.…”

“…Chitosan is a linear polymer that is produced from chitin via the deacetylation process [ 1 ]. Chitosan comprises some excellent properties including non-toxicity, adsorption, biocompatibility, and biodegradability, thus, it can potentially be used in many fields such as medicine, wastewater treatment, agriculture, and functional food [ 2 , 3 , 4 , 5 , 6 , 7 ]. One of the most challenging applications of chitosan is its poor solubility in a neutral aqueous solution.…”