1. A method for treating wastewater produced by washing laver processing seawater is characterized by comprising the following steps:

(a) washing and draining seawater processed by laver, automatically flowing into a set coarse grating, and automatically flowing into a lifting pump room;

(b) pumping the wastewater into a grit chamber for grit settling;

(c) the wastewater after the sand setting treatment automatically flows into a fine grid, and automatically flows into a regulating tank after passing through the fine grid;

(d) pumping the regulated wastewater into an advanced oxidation pond for oxidation reaction, and adding acid, hydrogen peroxide and iron ions;

(e) automatically flowing the wastewater subjected to the advanced oxidation reaction in the step (d) to a coagulating sedimentation tank for coagulating sedimentation, and simultaneously adding alkali liquor, PAM and PAC;

(f) and (e) automatically flowing the wastewater subjected to the coagulating sedimentation treatment in the step (e) to a contact disinfection tank, and adding a prepared sodium hypochlorite solution for disinfection.

2. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the width of the grid is as follows: b900 mm, grid gap: b is 10-20mm, the water depth before the grid is as follows: h is 0.9m, grid inclination: α is 75 °.

3. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the adjusting mode of the adjusting tank in the step (c) is an aeration mode, the adjusting time is 10-24 hours, a perforation aeration mode is adopted, and the aeration rate is 2-5 m³/m²。

4. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the concentration of the hydrogen peroxide solution is configured to be 30 percent; the acid is 98% concentrated sulfuric acid; the iron ions are ferrous sulfate with the preparation concentration of 10-20%; wherein the volume concentration of the 30% hydrogen peroxide is 2-5 per mill, the concentration of ferrous sulfate is 100-200 mg/L, and the volume concentration of the concentrated sulfuric acid is 1-2 per mill.

5. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the advanced oxidation pond is internally provided with an internal reflux system, and the reflux ratio is 100-300%.

6. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the advanced oxidation pond is provided with four grids, the first grid is an acid regulation reaction, concentrated sulfuric acid is added into the first grid, and the pH value is regulated to 4-5; the second to the fourth grids are reaction tanks, and the residence time is 1-2 h; and respectively adding hydrogen peroxide and ferrous sulfate solution into the second grid to the third grid in a multi-point adding mode.

7. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the reaction mode adopted in the step (d) is a complete mixing type, and the hybrid power is 5-6W/m³And (4) waste water.

8. The method for treating seawater cleaning wastewater from laver process according to claim 1, wherein: the alkali liquor is 30% sodium hydroxide solution.

Background

The laver processing season is concentrated from 10 months to 2 months of the next year. The laver processing machine is continuously operated for 24 hours in the processing season, and the laver processing needs to consume a large amount of fresh water and seawater. The processing technology of the laver comprises the following steps: harvesting → picking up vegetables and washing diatom → washing with seawater → chopping, washing with fresh water → size mixing → cake making and dewatering → drying → stripping → selecting and grading packaging and other process flows.

(1) And (3) fresh laver treatment: adding refrigerant to lower the temperature inside the prototheca to 5 deg.C, and storing for 3-6 hr.

(2) Picking up vegetables and cleaning diatoms: the laver is dehydrated by high-speed centrifugation, stored for 48-72 hours at the temperature of minus 20 ℃ and then washed and processed, and the color and the luster of the laver are obviously improved.

(3) Washing with seawater: the resistance of the cultivated laver to fresh water is generally poor, the longer the treatment time with fresh water is, the greater the influence on color and luster and the loss of flavor components such as amino acid and the like are, and clean seawater is used for cleaning before cutting vegetables.

(4) Chopping and fresh water cleaning: cutting vegetable with a machine, and cleaning with fresh water.

(5) And (3) cake making and dewatering: and (5) centrifugally dewatering to prepare cakes.

(7) And (3) drying: mechanically drying, wherein the water content of the dried laver is generally controlled at 10-12%.

(8) And (6) stripping.

(9) And (5) packaging and storing.

A large amount of processing water is generated in the laver production and processing process, particularly, seawater cleaning wastewater has high salt content, particularly, the content of chloride ions is 10000-30000mg/l, and simultaneously, organic matters such as laver fragments, soluble protein and the like and silt and the like are contained, and pollution factors are mainly expressed as COD (chemical oxygen demand)_Cr、BOD₅SS, chromaticity, ammonia nitrogen and the like. As the content of chloride ions in the seawater cleaning wastewater is higher, the common biochemical treatment method is difficult to carry out, and the standard treatment difficulty is higher.

Disclosure of Invention

Aiming at the chlorine ions existing in the seawater cleaning wastewater generated in laver processingThe invention provides a process method aiming at the characteristics of water quality and water quantity of laver processing seawater cleaning wastewater, which has the advantages of high seed content, high processing difficulty, poor processing effect and the like_CrAnd TP, SS, ammonia nitrogen and other characteristic substances enable the laver processing seawater cleaning wastewater to reach the first class A standard in the pollutant discharge standard of urban sewage treatment plants (GB 18918-2002) after being processed, wherein the total nitrogen is directly discharged at 25mg/L (the instantaneous coefficient is 1.2) according to the pollutant discharge standard of water in food processing and manufacturing industry.

In order to solve the problems, the invention provides a method for treating wastewater generated in the process of cleaning seawater in laver processing, which comprises the following steps:

(a) washing and draining seawater processed by laver, automatically flowing into a set coarse grating, and automatically flowing into a lifting pump room;

(b) pumping the wastewater into a grit chamber for grit settling;

(c) the wastewater after the sand setting treatment automatically flows into a fine grid, and automatically flows into a regulating tank after passing through the fine grid;

(d) pumping the regulated wastewater into an advanced oxidation pond for oxidation reaction, and adding acid, hydrogen peroxide and iron ions;

(e) automatically flowing the wastewater subjected to the advanced oxidation reaction in the step (d) to a coagulating sedimentation tank for coagulating sedimentation, and simultaneously adding alkali liquor, PAM and PAC;

(f) and (e) automatically flowing the wastewater subjected to the coagulating sedimentation treatment in the step (e) to a contact disinfection tank, and adding a prepared sodium hypochlorite solution for disinfection.

Furthermore, seawater cleaning drainage for laver processing in the coarse grating and the lifting pump room automatically flows into a factory area drainage pipe from each workshop and then automatically flows into the coarse grating, the coarse grating is used for automatically intercepting and collecting residual laver leaves, and the collected residual laver leaves are recycled. Grid width: b900 mm, grid gap: b is 10-20mm, the water depth before the grid is as follows: h is 0.9m, grid inclination: α is 75 °;

further, the adjusting mode of the adjusting tank is an aeration mode, and the adjusting time is 10-24 h, adopting a perforation aeration mode, wherein the aeration rate is 2-5 m³/m²；

Further, adding hydrogen peroxide, acid and iron ions into the advanced oxidation pond, wherein the concentration of a hydrogen peroxide solution is configured to be 30%, sulfuric acid is 98% concentrated sulfuric acid, and the iron ions are ferrous sulfate with the configured concentration of 10-20%; the volume concentration of 30 percent hydrogen peroxide is 2-5 per mill, Fe²⁺The concentration of the concentrated sulfuric acid is 100-200 mg/L, and the adding volume concentration of the concentrated sulfuric acid is 1-2 per mill;

furthermore, an internal reflux system is arranged in the advanced oxidation pond, and the reflux ratio is 100-300%;

further, four grids are arranged in the advanced oxidation tank, the first grid is used for acid regulation reaction, concentrated sulfuric acid is added into the first grid to regulate the pH value to 4-5, the second grid to the fourth grid are used for reaction tank, and the retention time is 1-2 h; adding hydrogen peroxide and ferrous sulfate solution into the second grid to the third grid respectively, wherein the adding mode is multipoint adding;

furthermore, the reaction mode of the advanced oxidation pond is a complete mixing type, and the hybrid power is 5-8W/m³Waste water;

further, alkali liquor, PAM and PAC are added into the coagulating sedimentation, wherein the alkali liquor is 30% sodium hydroxide solution.

Furthermore, aiming at the high ion content in the wastewater and the corrosion effect on the pipeline, all process connecting pipelines adopt glass fiber reinforced plastic sand inclusion pipes.

Compared with the prior art, the invention has the beneficial effects that:

(1) the process for processing seawater cleaning wastewater by laver provided by the invention has the advantages of short process flow, simple operation and high treatment efficiency, ensures that the wastewater reaches the first-class A standard in the discharge standard of pollutants for municipal wastewater treatment plants (GB 18918-2002), wherein the total nitrogen is directly discharged at 25mg/L (the instantaneous coefficient is 1.2) according to the discharge standard of water pollutants for food processing and manufacturing industry.

(2) According to the process for processing seawater cleaning wastewater by laver, the advanced oxidation method adopts the modes of complete mixing, internal reflux and multipoint adding, so that the wastewater is fully contacted with the medicament in a fluidized state, the medicament utilization rate is improved, and the treatment effect is improved by about 15% compared with that of the traditional treatment process.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The invention is further described with reference to specific examples.

Example 1

As shown in figure 1, the seawater cleaning wastewater in a certain laver processing base in Jiangsu Liyunghong harbor is detected to have COD concentration of about 500mg/L, chloride ion concentration of about 12000mg/L, SS of 400mg/L, chroma of 1000, ammonia nitrogen of 35mg/L and TP of 15mg/L in a regulating reservoir, the seawater cleaning wastewater is treated by adopting the process of the invention, the designed treatment capacity is 10000t/d, and the steps are as follows:

(a) thick grid and elevator pump house: firstly, seawater cleaning drainage for laver processing automatically flows into a factory drain pipe from each workshop, then automatically flows into a coarse grating, the coarse grating is used for automatically intercepting and collecting residual laver leaves, and the collected residual laver leaves are recycled. Grid width: b900 mm, grid gap: b is 10-20mm, the water depth before the grid is as follows: h is 0.9m, grid inclination: alpha 75 DEG

(b) Sand setting: pumping the wastewater treated in the step (a) into a grit chamber for grit settling;

(c) fine grid and adjustment: automatically flowing the wastewater subjected to sand setting treatment in the step (b) into a fine grid, and automatically flowing the wastewater into a regulating tank after passing through the fine grid; the adjusting mode of the adjusting tank is aeration adjusting, the adjusting time is 12h, a perforation aeration mode is adopted, and the aeration rate is 2.5m³/m²；

(d) Advanced oxidation: pumping the adjusted wastewater in the step (c) into a high-grade oxidation pond for oxidation reaction, and adding acid, hydrogen peroxide and iron ions; adding concentrated sulfuric acid into the first grid, adjusting the pH value to 5, taking the second grid to the fourth grid as a reaction tank, and keeping the reaction tank for 1 h; adding hydrogen peroxide and ferrous sulfate solution into the second grid to the third grid respectively, wherein the adding mode is multipoint adding; the reaction mode is a complete mixing mode, and the hybrid power is 6W/m³Waste water; an internal reflux system is arranged in the fourth grid, and the reflux ratio is 200%.

(e) Coagulating sedimentation: the step (A) isd) The wastewater after the advanced oxidation reaction automatically flows to a coagulating sedimentation tank for coagulating sedimentation, alkali liquor, PAM and PAC are added simultaneously, and the ascending flow velocity of the coagulating sedimentation tank is 8m/m²；

(f) Contact disinfection: and (e) automatically flowing the wastewater subjected to the coagulating sedimentation treatment in the step (e) to a contact disinfection tank, and adding a prepared sodium hypochlorite solution for disinfection.

(g) Aiming at the high ion content in the wastewater and the corrosion effect on the pipeline, all process connecting pipelines adopt glass fiber reinforced plastic sand inclusion pipes.

The final COD effluent concentration of the wastewater treated by the embodiment is 41mg/L, the SS is 8mg/L, the chroma is 2 times, the ammonia nitrogen is 10mg/L, and the TP is 3mg/L, which all reach the first grade A standard in the discharge Standard of pollutants for municipal wastewater treatment plant (GB 18918-2002), wherein the total nitrogen is directly discharged at 25mg/L (the instantaneous coefficient is 1.2) according to the discharge Standard of pollutants for Water for food processing and manufacturing industry

Example 2

As shown in figure 1, seawater cleaning wastewater in a certain laver processing base in Jiangsu salt city has COD concentration of 430mg/L, chloride ion concentration of 15000mg/L, SS of 300mg/L, chroma of 1200, ammonia nitrogen of 30mg/L and TP of 12mg/L detected in a regulating tank, and is treated by adopting the process of the invention with the designed treatment capacity of 30000t/d, and the steps are as follows:

(a) thick grid and elevator pump house: firstly, seawater cleaning drainage for laver processing automatically flows into a factory drain pipe from each workshop, then automatically flows into a coarse grating, the coarse grating is used for automatically intercepting and collecting residual laver leaves, and the collected residual laver leaves are recycled. Grid width: b900 mm, grid gap: b is 10-20mm, the water depth before the grid is as follows: h is 0.9m, grid inclination: α is 75 °.

(b) Sand setting: pumping the wastewater treated in the step (a) into a grit chamber for grit settling;

(c) fine grid and adjustment: automatically flowing the wastewater subjected to sand setting treatment in the step (b) into a fine grid, and automatically flowing the wastewater into a regulating tank after passing through the fine grid; the adjusting mode of the adjusting tank is aeration adjusting, the adjusting time is 10h, a perforation aeration mode is adopted, and the aeration rate is 3.0m³/m²；

(d) Advanced oxidation: pumping the adjusted wastewater in the step (c) into a high-grade oxidation pond for oxidation reaction, and adding acid, hydrogen peroxide and iron ions; adding concentrated sulfuric acid into the first grid, adjusting the pH value to 5, taking the second grid to the fourth grid as a reaction tank, and keeping the time for 1.2 h; adding hydrogen peroxide and ferrous sulfate solution into the second grid to the third grid respectively, wherein the adding mode is multipoint adding; the reaction mode is a complete mixing mode, and the hybrid power is 5W/m³Waste water; an internal reflux system is arranged in the fourth grid, and the reflux ratio is 100 percent.

(e) Coagulating sedimentation: automatically flowing the wastewater subjected to the advanced oxidation reaction in the step (d) to a coagulating sedimentation tank for coagulating sedimentation, and simultaneously adding alkali liquor, PAM and PAC, wherein the ascending flow velocity of the coagulating sedimentation tank is 9m/m²；

(f) Contact disinfection: and (e) automatically flowing the wastewater subjected to the coagulating sedimentation treatment in the step (e) to a contact disinfection tank, and adding a prepared sodium hypochlorite solution for disinfection.

(g) Aiming at the high ion content in the wastewater and the corrosion effect on the pipeline, all process connecting pipelines adopt glass fiber reinforced plastic sand inclusion pipes.

The final COD effluent concentration of the wastewater treated by the embodiment is 35mg/L, the SS is 5mg/L, the chroma is 1 time, the ammonia nitrogen is 8mg/L, and the TP is 2mg/L, which all reach the first grade A standard in the discharge Standard of pollutants for municipal wastewater treatment plant (GB 18918-2002), wherein the total nitrogen is directly discharged at 25mg/L (the instantaneous coefficient is 1.2) according to the discharge Standard of pollutants for Water in food processing and manufacturing industry.

The above description is a more detailed description of the present invention with reference to specific preferred embodiments, and it is not intended to limit the present invention to the specific embodiments described above. It will be apparent to those skilled in the art that various modifications, additions, substitutions, and the like can be made without departing from the spirit of the invention.