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Recovery of proteins and lipids from dairy wastewater using food grade sodium lignosulphonate

Gopinatha Kurup, Geethu, Adhikari, Benu, Zisu, Bogdan
Water resources and industry 2019 v.22 pp. 100114
biochemical oxygen demand, casein, coagulants, colloids, lignosulfonates, lipid content, lipids, manufacturing, pH, protein content, sodium, temperature, turbidity, wastewater
Dairy manufacturing sector generates large quantity of nutrient-rich wastewater which requires treatment before it can be released into the environment. This study aimed to use a low-cost food grade sodium lignosulphonate (Na-lignosulphonate) to recover proteins and lipids from dairy wastewater and reduce the BOD. The colloidal particles of wastewater sample were precipitated with varying the concentration of Na-lignosulphonate (0.002–0.032%, w/v) and pH of medium (1.0–3.5). Experiments were conducted at ambient (22 °C) and mildly elevated (40 °C) temperatures. At the optimum concentration (0.016%, w/v) of Na-lignosulphonate, the highest turbidity removal (98%) was achieved at pH 3.5 and at both temperatures. This method recovered 96% lipids and 46% proteins (mostly caseins) and reduced the BOD by 73% at 22 °C. Na-lignosulphonate is found to be an effective coagulant owing to its ability to readily complex with positively charged colloidal particles at acidic pH.