阅读说明：本技术 一种复合絮凝剂及采用该絮凝剂处理污水的方法 (Composite flocculant and method for treating sewage by using same ) 是由 廖望 高建领 赖舒雁 龙鑫磊 于 2019-10-09 设计创作，主要内容包括：本发明公开了一种复合絮凝剂及采用该絮凝剂处理污水的方法,所述复合絮凝剂化学改性天然高分子、聚乙烯醇和絮凝促进剂组成。本发明公开的复合絮凝剂对混合污水絮凝效果好,尤其对印染废水、浑浊泥沙浆、生活污水任何两种或三种所构成的混合污水净水效果明显,具有用量少、价格低、无二次污染、效率高、兼具杀菌的效果。经试验证实采用本发明的复合絮凝剂处理后的排出清液与废水相比其浊度降低了85-97%,COD去除率80-97%,除菌率35-50%,且本发明公开的处理混合污水的方法操作简单、处理方便、成本低、适用于工业化大规模生产。(the invention discloses a composite flocculant and a method for treating sewage by adopting the same. The composite flocculant disclosed by the invention has a good flocculation effect on mixed sewage, particularly has an obvious water purification effect on mixed sewage consisting of any two or three of printing and dyeing wastewater, turbid silt and domestic sewage, and has the effects of low consumption, low price, no secondary pollution, high efficiency and sterilization. Experiments prove that compared with waste water, the turbidity of the discharged clear liquid treated by the composite flocculant is reduced by 85-97%, the COD removal rate is 80-97%, and the degerming rate is 35-50%.)

1. The composite flocculant is characterized by comprising the following components in parts by weight:

chemically modifying natural polymer: 0.01-100 mg/mL;

polyvinyl alcohol: 0-100 mg/mL;

Flocculation accelerator: 0.001-10 mg/mL;

Wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

2. the composite flocculant of claim 1, wherein the composite flocculant comprises the following components in percentage by weight:

Chemically modifying natural polymer: 0.1-10 mg/mL;

polyvinyl alcohol: 10-50 mg/mL;

Flocculation accelerator: 0.01-1 mg/mL;

Wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

3. The composite flocculant of claim 1, wherein the composite flocculant comprises the following components in percentage by weight:

chemically modifying natural polymer: 5 mg/mL;

polyvinyl alcohol: 34 mg/mL;

flocculation accelerator: 0.6 mg/mL;

wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

4. the composite flocculant of claim 1, 2 or 3, wherein the chitosan is derived from industrial deacetylated chitin, and has a deacetylation degree of not less than 70% and a molecular weight of 2X 105 to 5X 105.

5. the composite flocculant of claim 1, 2 or 3, wherein the cationized starch is derived from corn, potato or sweet potato, and the cationized degree of substitution is 0.2-0.8 after cationization modification.

6. The composite flocculant of claim 1, 2 or 3, wherein the flocculation promoter is a combination of one or more of borax, boric acid, and glutaraldehyde.

7. a method for treating sewage by using the composite flocculant of claim 1, 2 or 3, characterized by comprising the steps of:

s1, adding chemically modified natural polymer and polyvinyl alcohol into the sewage to enable the composite flocculant to reach the required concentration in the sewage;

S2, adding a flocculation accelerator into the sewage, and fully mixing to enable the sewage to reach the required concentration in the mixed sewage;

S3, standing the sewage added with the composite flocculant for 0.5-2 hours, and discharging supernatant, namely the treated sewage.

8. the method for treating sewage by using the composite flocculant as claimed in claim 7, wherein the sewage is a mixture of any two or more of printing and dyeing wastewater, turbid silt and domestic sewage.

Technical Field

the invention relates to the technical field of sewage treatment, in particular to a composite flocculant and a method for treating sewage by adopting the same.

Background

The economic development mode of China already enters the key period of transformation and upgrading, and the environmental protection requirement is stricter. However, many industrial sectors, such as paper making, sugar making, alcohol, starch, monosodium glutamate, tanning, food industries, produce high concentrations of organic effluents during the production process. Other sectors, such as printing, plating, petrochemical, smelting, etc., also produce large amounts of wastewater. Meanwhile, along with the enlargement of the urban scale, the pollution of sewage of medical institutions, urban domestic sewage and aquaculture wastewater is serious, and pathogenic bacteria contained in the sewage cause high worry of people.

at present, methods for treating sewage can be divided into: (1) physical method: the sewage is treated by the modes of filtering, precipitating, air floating and the like, and the method has the advantages of short separation time, simple device, large treatment capacity and the like, but has higher requirements on the performance of treatment equipment and higher investment cost and operating cost; (2) the chemical method comprises the following steps: the method has the advantages that toxic elements in water are treated by adding specific chemical reagents such as flocculating agents, complexing agents or acid-base treating agents, and the method has the advantages of low capital investment, simple process, easiness in operation, low energy consumption and strong adaptability to temperature change, but has the defect of single property, cannot treat high-concentration organic wastewater with complex content, and particularly has low removal rate of small-molecular organic matters in the wastewater; (3) photosynthetic bacteria method: the method has high efficiency of removing organic pollutants, small investment and small occupied area, and the thallus sludge is protein feed which is harmless to human and livestock and rich in nutrition, but the method is sensitive to temperature change, needs corresponding heating and heat preservation devices, and has the defects of high operating cost, inconvenient management and the like; (4) the biological method comprises the following steps: the method has the advantages of mature and reliable technology, strong impact resistance, good treatment effect and the like, and has the defects of large occupied area, large energy consumption, high investment cost and operation cost, great influence by environmental conditions such as the water temperature, the pH value and toxic substances of the wastewater, incomplete treatment and difficulty in reaching the discharge standard; (5) electrochemical method: the advantages are small volume of the equipment, small occupied area, good controllability, and the defects of low current density, high operation cost or side reaction caused by large mass transfer resistance of pollutants.

among them, the flocculation precipitation method is the most common water treatment method, and has the widest application and the lowest cost. However, the polluted water body becomes complicated after confluence, the requirement for sewage treatment is higher and more complicated, and secondary pollution is easily caused when the treatment is improper, so that the development of a flocculating agent which is high in efficiency, excellent in flocculation performance, low in cost and suitable for mixed sewage is urgently needed.

disclosure of Invention

the invention aims to overcome the defects of the prior art and provide the composite flocculant which has high treatment efficiency, simple process and low cost and does not cause secondary pollution;

the invention also aims to provide a method for treating sewage by using the flocculant.

the purpose of the invention is realized by the following technical scheme: the composite flocculant comprises the following components in parts by weight:

Chemically modifying natural polymer: 0.01-100 mg/mL;

polyvinyl alcohol: 0-100 mg/mL;

flocculation accelerator: 0.001-10 mg/mL;

Wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

further, the composite flocculant comprises the following components in percentage by weight:

Chemically modifying natural polymer: 0.1-10 mg/mL;

Polyvinyl alcohol: 10-50 mg/mL;

Flocculation accelerator: 0.01-1 mg/mL;

wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

preferably, the composite flocculant comprises the following components in percentage by weight:

Chemically modifying natural polymer: 5 mg/mL;

polyvinyl alcohol: 34 mg/mL;

Flocculation accelerator: 0.6 mg/mL;

wherein, the chemically modified natural polymer is one or two of chitosan and cationized starch.

Further, the chitosan is derived from industrial deacetylated chitin, the deacetylation degree of the chitosan is not less than 70%, and the molecular weight range is 2 x 105-5 x 105.

Further, the cationized starch is derived from corn, potato or sweet potato, and the cationized substitution degree of the cationized starch is 0.2-0.8 after cationization modification.

further, the flocculation accelerator is one or a combination of borax, boric acid and glutaraldehyde.

the method for treating sewage by adopting the composite flocculant comprises the following steps:

S1, adding chemically modified natural polymer and polyvinyl alcohol into sewage to enable the composite flocculant to reach the required concentration in the sewage;

s2, further adding a flocculation accelerator into the sewage, and fully mixing to enable the sewage to reach the required concentration in the mixed sewage;

S3, standing the sewage added with the composite flocculant for 0.5-2 hours, and discharging supernatant, namely the treated sewage.

Further, the sewage is the mixture of any two or more of printing and dyeing wastewater, turbid silt and domestic sewage.

The invention has the following advantages: the composite flocculant disclosed by the invention has a good flocculation effect on mixed sewage, particularly has an obvious water purification effect on mixed sewage consisting of any two or three of printing and dyeing wastewater, turbid silt and domestic sewage, and has the effects of low consumption, low price, no secondary pollution, high efficiency and sterilization. Experiments prove that compared with waste water, the turbidity of the discharged clear liquid treated by the composite flocculant is reduced by 85-97%, the COD removal rate is 80-97%, and the degerming rate is 35-50%.

Detailed Description

The invention is further described below with reference to examples, without limiting the scope of the invention to the following: