Pig farm wastewater enhanced flocculation method

Abstract

The invention discloses a preparation method of a starch-based composite flocculant. The preparation method comprises: dissolving starch in water to obtain a 10-20% starch solution, slowly adding NaOH to the 50-60 DEG C water bath at a uniform speed according to a mass ratio of the NaOH to the starch of 1:8-12, and carrying out a stirring reaction for 40-80 min to obtain a modified starch solution; adjusting the pH value of the modified starch solution to 2.0-3.5 with sulfuric acid; and adding polysilicate ferric to the modified starch solution according to a ratio of the starch to the polysilicate ferric of 0.25-0.5:1, maintaining the pH value at 2.0-3.0, carrying out a reaction for 3.5-4.5 h in a 50-60 DEG C constant temperature oscillator, and standing overnight so as to age. According to the present invention, the starch-based composite flocculant has characteristics of no toxicity and no residue, has the SS removal efficiency of more than 90%, and has the COD removal efficiency of more than 60%, wherein the treatment cost is 0.2 yuan/m<3>, and the separated pig manure can further be directly used as the fertilizer for fruit trees and forest, and can be used as the raw material of the organic fertilizer.

Description

technical field [0001] The invention belongs to waste water treatment technology, specifically relates to the treatment of pig farm waste water, and more specifically relates to a pig farm waste water flocculant and a treatment method thereof. Background technique [0002] Large-scale pig raising has become the main mode of raising pigs, but pollution prevention and control management is relatively lagging behind, and pollutant discharge is becoming more and more serious. It has become an important factor affecting the quality of water environment and directly threatens the safety of drinking water sources. Strengthening the treatment and reuse of wastewater from livestock and poultry breeding is an important part of intensive and healthy farming. It is of great significance to promote the reduction of pollutants, improve the living environment in rural areas, ensure the safety of drinking water sources, and promote the healthy development of livestock and poultry breeding. ...

AI Technical Summary

Problems solved by technology

When conventional inorganic flocculants such as polyaluminum chloride (PAC) and polyferric sulfate (PFS) are used to treat this type of wastewater, it is difficult to achieve the ideal decolorization and COD reduction treatment effects, and in recent years, it has been found that senile dementia The occurrence of the disease is related to the residual accumulation of aluminum ions

Organic flocculants include synthetic polymer flocculants and natural polymer flocculants. Synthetic polymer flocculants such as polyacrylamide have the advantages of less dosage, fast flocculation speed, less influence by coexisting salts, and less sludge generation. However, the residual monomers of such polymers have "three-caused" effects (teratogenic, carcinogenic, and mutagenic) and are difficult to degrade

In order to improve the decolorization efficiency, dicyandiamide-formaldehyde (DCD-HCHO) condensation polymers have been widely used for decolorization in recent years. However, in the application, it was found that such substances have limited degree of polymerization, low charge density, small molecular weight, and insufficient active functional groups, resulting in precipitation nets. The effect is poor, the formation of flocs is small, it is difficult to settle quickly in a short time, and the treatment cost is high. Therefore, in engineering practice, it is often necessary to use it in conjunction with PAC or PFS to achieve the flocculation and decolorization effect. However, due to the combination of PAC or PFS and DCD -The structure of HCHO is not similar, the degree of crystallinity is different, etc., the compatibility between the two is poor, the difficulty of compounding is quite large, and it must be added in batches, which increases the construction and operation costs

[0006] In terms of patents, for example, the Chinese invention patent ZL200710029328.6 relates to a method for preparing a polymeric borosilicate magnesium aluminum iron flocculant, and the Chinese invention patent ZL201010525993.6 is a method for treating complex chemical wastewater by combining Fenton and starch-based flocculants , but the former is unstable and needs to be stored away from light; the latter mainly treats high-concentration complex chemical wastewater, and the starch-based flocculant must be used in combination with Fenton to show the effect

Enhanced flocculation is an important technical means for solid-liquid separation in current aquaculture wastewater treatment, but there are problems such as poor flocculation effect of inorganic flocculants and residual toxic monomers in organic flocculants, and the flocculation effects of both are easily affected by the pH value of water. influences