Wastewater treatment method in agar production

The invention belongs to the technical field of sewage treatment, and relates to a wastewater treatment method in agar production. The method comprises the five steps of flocculation, separation, ultrafiltration, nanofiltration and hyperfiltration, wastewater and flocculant are mixed to conduct flocculation reaction, ultrafiltration is conducted on the obtained wastewater mixture to remove residual polysaccharide and protein in the wastewater mixture, nanofiltration is conducted to remove high valence ions in the wastewater mixture, and the wastewater mixture only contains monovalent ions of Na and K ; hyperfiltration is conducted to obtain hyperfiltration permeate liquid of which the water quality accords with national tap water standards, wastewater produced in the agar production process is converted into tap water capable of being recycled and feed additives used for providing abundant nutrition for animals, sewage discharge is reduced, water used in agar production is saved, the production cost is reduced, the economic benefit is increased, a guarantee is provided for sustainable development of agar production enterprises, and the wide application prospect is achieved; the principle is scientific and reasonable, the operability and practicability are strong, energy conservation and environmental protection are achieved, the usage environment is friendly, and application and promotion are easy.