CN111018237A

CN111018237A - Method for efficiently purifying sewage of livestock and poultry farm by using water spinach

Info

Publication number: CN111018237A
Application number: CN201911181684.9A
Authority: CN
Inventors: 黎华寿; 崔星怡; 黄山; 梁秋梨
Original assignee: Guangzhou Longyunbo Environmental Protection Technology Co ltd; South China Agricultural University
Current assignee: Guangzhou Longyunbo Environmental Protection Technology Co ltd; South China Agricultural University
Priority date: 2019-11-27
Filing date: 2019-11-27
Publication date: 2020-04-17
Anticipated expiration: 2039-11-27
Also published as: CN111018237B

Abstract

The invention discloses a method for efficiently purifying sewage of a livestock and poultry farm by using water spinach. The method comprises the following steps: adjusting organic wastewater generated by solid-liquid separation of domestic sewage and livestock waste, and then sequentially feeding the organic wastewater into a black film methane tank, an anaerobic fermentation tank and a DST advanced treatment biochemical tank for treatment, feeding the treated water into an artificial wetland, and allowing the sewage to stay in the artificial wetland for 10-30 days; the artificial wetland is used for planting water spinach; and the water treated by the artificial wetland enters a flocculation sedimentation tank for sedimentation treatment, and then enters a drainage tank through an MBR membrane and RO combined system. The method combines the characteristics of the aquaculture sewage, utilizes the strengthening effect of the water spinach on the wetland, and obviously reduces the content of pollutants such as heavy metal, organic matters, nitrogen, phosphorus and the like in the water body through the processes of adsorption, ion exchange, plant absorption and transportation and the like, and has the advantages of convenient operation and management, low treatment cost and good environmental protection.

Description

Method for efficiently purifying sewage of livestock and poultry farm by using water spinach

Technical Field

The invention belongs to the technical field related to livestock and poultry breeding sewage treatment. More particularly, relates to a method for efficiently purifying sewage of a livestock and poultry farm by using water spinach.

Background

The large-scale cultivation can bring higher economic benefit, but also brings the problem of environmental pollution caused by concentrated discharge of overproof sewage. The biogas slurry is a byproduct generated after the anaerobic fermentation of organic wastes generates biogas, contains various nutrient elements and physiological active substances required by plant growth, and can be recycled by agriculture due to the effects of quick acting, nutrition, bacteriostasis, stimulation, stress resistance and the like. At present, biogas slurry is mostly used as a biological fertilizer and a biological pesticide in agricultural production.

However, researches find that the biogas slurry generated in a pig farm has the phenomenon of heavy metal exceeding during application, can bring potential safety hazard problems to farmland soil environment and agricultural product quality (Liyaoqin and the like, 2012), and harms human health through a food chain. Research shows that the pig manure source biogas slurry contains a large amount of trace nutrients required by crop growth and main harmful heavy metal elements, and the contents are as follows: the nitrogen content is 1488-10109 mg. L^-1The average content is 5514 mg.L^-1Mainly exists in the form of ammonium nitrogen, and the ammonium nitrogen can account for 68.7 to 89.8 percent of the total nitrogen; the phosphorus content is 1123-3318 mg.L^-1To (c) to (d); potassium contentAt 36 to 167 mg.L^-1To (c) to (d); in addition, the biogas slurry also contains a large amount of iron (36.6 mg. L)^-1) Copper (13.3 mg. L)^-1) And zinc (18.0 mg. L)^-1) Contains trace elements, and arsenic (9.05 mg. L)^-1) Nickel (0.77 mg. L)^-1) Lead (0.21 mg. L)^-1) Cadmium (0.022 mg. L)^-1) And the like. Therefore, when biogas slurry is used in agriculture or directly discharged, the high content of nutrient salts and heavy metals in the biogas slurry causes the risk of pollution to crops and ecological environment (Zhao national Hua et al, 2014).

Because of the advantages of less investment, easy maintenance and the like, the artificial wetland is more and more applied to sewage treatment. However, the artificial wetland has a very complicated mechanism process for purifying the sewage, and the plant absorption, the microbial metabolism, the substrate adsorption, the filtration and the precipitation play a key role in the removal process of the pollutants in the artificial wetland. Different plants have different purification effects on sewage, and because the culture wastewater components are complex, wetland plants with better purification effects on certain pollutants in water do not represent that the wetland plants have better purification effects on other pollutants, so that the aquatic plant screening is an important link for improving the sewage purification efficiency of livestock and poultry farms. At present, most of researches on artificial wetland by researchers are focused on the removal effect of landscape plants (such as canna, reed and the like as wetland plants) on nitrogen and phosphorus, and the attention on crops is less. And only aims at the treatment of the pollutants of the livestock, but does not consider the recycling of the pollutants of the livestock while the pollutants are treated so as to change waste into valuable, the treatment effect is not sufficient, and the energy conservation and the environmental protection are not fully realized. In addition, the existing research basically aims at the single release of nitrogen and phosphorus for repairing, and does not reduce the release of other pollutants such as heavy metal, and the like, so that the existing research obviously has great limitation on the repair of the polluted culture wastewater which needs to control the endogenous release of various pollutants.

Disclosure of Invention

The invention aims to provide a method for efficiently purifying sewage of a livestock and poultry farm by using water spinach aiming at the defects of the existing aquaculture wastewater treatment technology and the artificial wetland technology.

The invention is realized by the following technical scheme:

a method for efficiently purifying sewage of a livestock and poultry farm by using water spinach comprises the following steps:

s1, adjusting organic wastewater generated by solid-liquid separation of domestic sewage and livestock waste, and then sequentially feeding the organic wastewater into a black film methane tank, an anaerobic fermentation tank and a DST advanced treatment biochemical tank for treatment, feeding the treated water into an artificial wetland, and allowing the sewage to stay in the artificial wetland for 10-30 days in a hydraulic manner; the artificial wetland is used for planting water spinach;

and S2, allowing the water treated by the artificial wetland to enter a flocculation sedimentation tank for sedimentation treatment, and allowing the water to enter a drainage tank through an MBR (membrane bioreactor) membrane and RO (reverse osmosis) combined system, wherein the water in the drainage tank is discharged into the fishpond only when meeting the specified standard.

The invention firstly carries out primary solid-liquid separation on livestock sewage, the separated solid manure residue is fermented to be used as an organic fertilizer raw material for cyclic utilization or returning to the field for utilization, scientific cyclic utilization and planting are combined, urine, sewage and production and living water which are intercepted by emission reduction and solid-liquid separation sequentially flow into a black film methane tank, an anaerobic fermentation tank and a DST advanced treatment biochemical tank for multi-stage treatment and then enter an artificial wetland system, aiming at the characteristics of livestock and poultry breeding sewage, the contents of heavy metals, organic matters, nitrogen, phosphorus and other pollutants in the water body are reduced by utilizing the strengthening effect of water spinach on the wetland and carrying out the processes of adsorption, ion exchange, plant absorption and transportation and the like, so that the effluent quality indexes are Total Phosphorus (TP) and ammonia Nitrogen (NH)₄ ⁺N) and COD meet the discharge standard of pollutants for livestock and poultry breeding (DB 44/613-2009), and the content indexes of As, Cu and Zn meet the discharge standard of Integrated wastewater (GB 8978-88). The whole process carries out solid-liquid-gas all-around treatment and utilization on the excrement, and specifically comprises the following steps: the biogas is generated for production and life or power generation, the treated water is subjected to nutrient recovery and field returning utilization, and the filtered manure residue yard is subjected to organic fertilizer recovery or field returning utilization, so that the energy recycling is realized. The treated reclaimed water has zero pollution discharge when the chemical reaction reaches the standard time limit and has good environmental protection. The whole treatment process is efficient, environment-friendly, energy-saving, economical and safe, and effectively solves the problems of the prior artAnd (4) deficiency.

In some embodiments, the variety of the water spinach is selected from one or more of green stem leaf water spinach of harbor species, white leaf water spinach of Taiwan region, D-95 water spinach of vegetable grower, Thailand leaf water spinach, large white leaf water spinach of harbor species, Thailand middle leaf water spinach, Guangdong pure green leaf water spinach, green leaf water spinach of white bone, Jiangxi big leaf water spinach, North river big leaf water spinach, 999 green leaf water spinach of white bone, Jashuai leaf water spinach, white stem leaf water spinach, Thailand water spinach, white leaf water spinach of Taiwan region, green stem leaf water spinach of Taiwan region, white stem leaf water spinach of Taiwan region, and oil green water spinach.

In other preferred embodiments, the variety of the water spinach is one or more selected from the group consisting of white leaf water spinach in Taiwan, D-95 water spinach in vegetable grower, green leaf water spinach in harbor and water spinach in Thailand. Through extensive and intensive research, the invention discovers that the transport coefficients of 4 varieties (Taiwan area large-leaf white-bone water spinach, vegetable farmer D-95 water spinach, harbor green stem leaf water spinach and Thailand bamboo leaf water spinach) with higher accumulated As content are all larger than 1, namely the content of the As in the overground part is higher than that in the underground part, wherein the transport coefficient of the water spinach except Thailand bamboo leaf is 1.08, and the content of the As in the overground part is slightly higher than that in the underground part. And the biomass of the white-leaf water spinach in Taiwan, the D-95 water spinach in vegetable growers and the green-stem leaf water spinach in harbor are higher and are all more than 10 g. Therefore, in summary, the swamp cabbage variety with relatively high As accumulation is Taiwan white-leaf swamp cabbage, vegetable D-95 swamp cabbage, green-stem-leaf swamp cabbage, and Thailand bamboo leaf swamp cabbage.

In some embodiments, S1, adding a filler selected from one or more of zeolite, charcoal, composite microbial agent or chlorella into the artificial wetland system.

In other preferred embodiments, the filler is selected from a mixture of biochar and chlorella, or a mixture of zeolite, biochar, microorganisms and chlorella, or a mixture of biochar and microorganisms, or a mixture of zeolite and microorganisms. According to the invention, by adding zeolite, charcoal, compound microbial agent or chlorella filler, the interaction among plants, matrix and microorganisms is enhanced, the strengthening effect on the wetland is enhanced, and the removal efficiency of heavy metals and nitrogen and phosphorus in sewage is effectively improved.

In some preferred embodiments, in the mixture of biochar and chlorella, the mass ratio of biochar to chlorella is 50-150: 3; in the mixture of the zeolite and the chlorella, the mass ratio of the zeolite to the chlorella is 50-150: 3; in the mixture of the zeolite, the biochar, the microorganisms and the chlorella, the mass ratio of the zeolite to the biochar to the microorganisms to the chlorella is 50-150: 50-150: 1: 3; in the mixture of the biochar and the microorganisms, the mass ratio of the biochar to the microorganisms is 50-150: 1; in the mixture of the zeolite and the microorganism, the mass ratio of the zeolite to the microorganism is 50-150: 1.

in some embodiments, the complex microbial agents include bacillus subtilis, yeast, lactic acid bacteria, and flocculating bacteria.

In some preferred embodiments, the compound microbial agent is prepared by mixing bacillus subtilis, saccharomycetes, lactic acid bacteria and flocculating bacteria according to the weight ratio of 5-10: 2-10: 1-6: 1-5.

In some preferred embodiments, the total viable bacteria number of the compound microbial agent is more than or equal to 5.0 x 10⁹cfu·g^-1Preferably 5.0X 10⁹～5.0×10¹⁰cfu·g^-1。

In some preferred embodiments, the chlorella is added as a chlorella solution in logarithmic growth phase.

In some preferred embodiments, chlorella is cultured conventionally to obtain a seed solution, and then the seed solution is cultured in a 1: 10, transferring the mixture into a chlorella acclimation culture medium, and culturing for 12 hours to obtain chlorella liquid. Can be (2-10) x 10⁸The input amount of the CFU is directly added into the chlorella solution in the artificial wetland, or the chlorella solution can be centrifuged, and then the precipitate is weighed and added.

In some preferred embodiments, the filler is added in an amount of 0.1 to 20g/L, preferably 5 to 15 g/L.

In some preferred embodiments, the solid manure residues produced by the solid-liquid separation in the step S1 are sent to a yard for organic fertilizer nutrient recovery or returning to the field for utilization or sent to a fermentation plant for treatment.

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

(1) the invention firstly carries out primary solid-liquid separation on livestock sewage, solid manure residues after separation are fermented to be used as organic fertilizer raw materials for cyclic utilization or returning to the field for utilization, scientific cyclic utilization and planting are combined, urine, sewage and production domestic water after emission reduction and solid-liquid separation and interception sequentially flow into a black film methane tank, a DST microorganism selection pond anaerobic fermentation tank and a DST advanced treatment biochemical tank for multi-stage treatment and then enter an artificial wetland system, and the content of heavy metals, organic matters, nitrogen, phosphorus and other pollutants in a water body is reduced by combining the characteristics of livestock breeding sewage and utilizing the strengthening effect of swamp cabbage on the wetland through the processes of adsorption, ion exchange, plant absorption and transportation and the like, so that the water quality indexes of effluent water are Total Phosphorus (TP) and ammonia Nitrogen (NH)₄ ⁺N) and COD meet the discharge standard of pollutants for livestock and poultry breeding (DB 44/613-2009), and the content indexes of As, Cu and Zn meet the discharge standard of Integrated wastewater (GB 8978-88).

(2) The invention has low construction cost, convenient operation and management, low treatment cost and can greatly save investment; and swamp cabbage is selected as wetland plants, so that the removal effect on arsenic, organic matters, nitrogen and phosphorus is good. The treated reclaimed water has zero pollution discharge when the chemical reaction reaches the standard time limit and has good environmental protection.

Drawings

FIG. 1 is a clustering tree diagram of As content in aerial parts of 19 varieties of water spinach.

Fig. 2 is a schematic view of an indoor simulated artificial wetland test site.

Detailed Description

The present invention is further illustrated by the following specific examples, which are not intended to limit the invention in any way. The present invention is not limited to the above embodiments, and any other changes, modifications, substitutions, combinations, and simplifications which do not depart from the spirit and principle of the present invention should be construed as equivalents and are intended to be included in the scope of the present invention.

Reagents, methods and apparatus used in the present invention are conventional in the art unless otherwise indicated.

Unless otherwise indicated, reagents and materials used in the following examples are commercially available.

Measurement of As, Cu, Zn

(1) Plant sample preparation: weighing 0.2g of plant dry sample, adding 8mL of nitric acid and 2mL of 30% hydrogen peroxide, performing microwave digestion (CEMMars6), determining the content of As in the digestion solution by using a double-channel atomic fluorescence spectrophotometer (AFS-230E, Beijing Korea Hai-Kui optical instruments Co., Ltd.), and determining the content of Cu and Zn in the digestion solution by using an atomic absorption spectrophotometer (ZEEnit700P, Germany Jena).

(2) Water sampling: 5mL of water sample is taken, 5mL of nitric acid is added, microwave digestion (CEM Mars6) is carried out, the content of As in the digestion solution is determined by a double-channel atomic fluorescence spectrophotometer (AFS-230E, Beijing Kochua Hai-Kuai optical instruments Co., Ltd.), and the content of Cu and Zn in the digestion solution is determined by an atomic absorption spectrophotometer (ZEEnit700P, Germany Jena).

Transfer coefficient calculation

Transfer coefficient is the above-ground As content/the underground As content

Determination of water quality

Total phosphorus: ammonium molybdate spectrophotometry (GB 11893-89);

ammonia nitrogen: sodium hypochlorite-salicylic acid spectrophotometry (HJ 534-2009);

COD_Cr: microwave digestion-Potassium dichromate method, according to the method of Dharmadhikari et al (2005), 3mL of a water sample was taken in a digestion tank, and 1.5mL of a potassium dichromate standard solution (1/6K) was added₂CrO₇0.2500 mol/L), 0.06g mercury sulfate, 4.5mL silver sulfate-sulfuric acid solution (5 g silver sulfate is added into 500mL concentrated sulfuric acid), microwave digestion (CEM Mars6) is carried out for 15min, 3 drops of ferroxyl test indicating solution are added, ammonium ferrous sulfate standard solution [ (NH)₄)₂Fe(SO₄)₂·6H₂O≈0.1mol/L]Titration;

pH: the pH meter (PB-10, Sartorius) directly.

The chlorella strain is purchased from the research institute of aquatic products in Zhujiang of Chinese aquatic science research institute, and is cultured in logarithmic growth phase according to the ratio of 1: 10 to BG11 medium without nitrogen, cultured under light intensity 2700Lx at 28 ℃ for 10 days to logarithmic phase, and centrifuged with 100mL centrifuge tubes at 3000 rpm to collect the pellet.

Example 1 selection of Water spinach variety

1. Method of producing a composite material

(1) The test is carried out in an ecological farm cement pond (with the length of 1m multiplied by the width of 1m multiplied by the height of 0.65m) of southern China agricultural university, 15 cement ponds are evenly divided into 4 cells (with the area of each cell being 0.5m multiplied by the width of 0.5m) with 60 cells in total, 57 cells (with 3 vacant cells and no plant) are needed for 3 times for all 19 swamp species to be tested, 20 seeds of 19 different swamp species are randomly sowed in each cell, and 4 plants are fixed after the 1 st true leaf of the plant grows out. During the test period, tap water with the same amount is added into the cement pool irregularly (1-2 d). And after planting for 60d (4-6 months in 2015), any one of 4 water spinach in each pool is used for measuring the biomass and arsenic content of 19 water spinach varieties.

(2) The test cement pond soil was from the cultivated layer of the ecological department farm of southern china university of agriculture. And after soil is collected, removing impurities such as broken stones and dead leaves, naturally drying, sieving by a 2mm sieve, and uniformly mixing for later use. The concentration of As-polluted soil in the cement pool community is set As 50mg As.kg^-1(arsenic trioxide is added according to the amount of 30cm of a plough layer), after rice aged As of one season is planted, samples are taken to detect the basic physicochemical properties, and the results are shown in Table 1.

TABLE 1 physicochemical Properties of the soil tested

(3) Treatment of plant samples: separating the overground part and the underground part (root system) of the whole water spinach plant, completely cleaning the water spinach plant by using tap water, distilled water and deionized water in sequence, absorbing the water on the surface of the plant by using absorbent paper, filling the plant into an envelope, numbering the plant, drying the plant in a 60 ℃ oven to constant weight, and weighing the dry weight. Then, the ground upper part and the ground lower part of the water spinach are crushed by a crusher and stored in a sealing bag for analyzing the content of total As.

Transfer coefficient is the aboveground As content/underground As content.

2. Results

(1) Influence of As stress on biomass of water spinach of different varieties

Biomass of table 219 variety of swamp cabbage

Note: all data are mean ± sem (n ═ 3), with different lower case letters in the same column indicating significant differences between species (p < 0.05).

As can be seen from Table 2, the aboveground biomass (dry weight basis) of 19 varieties of water spinach is 1.22-19.43 g, the mean value is 9.26g, the variety with the largest biomass is Thailand leaf water spinach, and the variety with the smallest biomass is green-bone leaf water spinach, with a difference of 15.93 times, wherein the biomass difference of the Thailand leaf water spinach from 5 varieties of Thailand leaf water spinach, Taiwan area white-bone leaf water spinach, Jiangxi big-leaf water spinach, 999 green-bone leaf water spinach and green-bone leaf water spinach reaches a significant level (p < 0.05); the biomass difference of the green petiolus lophatherum gracile swamp cabbage in the Taiwan region and the biomass difference of the two varieties of 999 green bone salix leaf swamp cabbage and the green bone salix leaf swamp cabbage reaches an obvious level (p is less than 0.05); and no significant difference between the biomass of the remaining varieties (p > 0.05); the biomass range of the underground part is 0.63-4.12 g, the difference is 5.6 times, the average value is 1.79g, and the biomass difference of the underground part among 19 swamp cabbage varieties reaches a significant level (p is less than 0.05).

(2) Differences in As content of different varieties of water spinach

TABLE 3 variety differences of As accumulation in the aerial and underground parts of Water spinach

As can be seen from Table 3, the accumulated As content of swamp cabbage is significantly different between different varieties (p)<0.05), the content range of As on the overground part of 19 varieties of water spinach is As follows: 0.73 to 191.12 mg/kg^-1And the difference is 261.81 times. Refer to GB 2762-^-1) And all the contents exceed the standard, which indicates that the water spinach planted in the heavily polluted soil is not suitable for eating. In addition, the content of As among the swamp cabbage varieties is very different, wherein the highest content of As in the overground part is 191.12 mg/kg of green stem leaf swamp cabbage which is a harbour variety^-1The content of As is 0.73 mg/kg for the oil green empty cabbage^-1(ii) a The underground part has the highest As content of 229.76 mg/kg of white-bone willow leaf water spinach in Taiwan^-1The variety with the lowest content is green bone willow leaf water spinach with the content of 78.57 mg/kg^-1. The transport coefficient difference of 19 swamp cabbage varieties is obvious, the lowest Taiwan white bone willow leaf swamp cabbage is 0.004, and the highest harbor green stem leaf swamp cabbage is 2.19. Wherein the transport coefficients of 4 varieties of white-leaf Chinese cabbage, D-95 Chinese cabbage, green-stem-leaf Chinese cabbage and Thailand bamboo-leaf Chinese cabbage in Taiwan are more than 1.

(3) Cluster analysis

As shown in FIG. 1, it was found by cluster analysis that 9 species such As Thailand white-stem salix leaf water spinach, Taiwan white-bone salix leaf water spinach, Taiwan green-stem lophatherum water spinach, Thailand water spinach, Hebei large-leaf water spinach, Yushuai bamboo leaf water spinach, 999 green-bone salix leaf water spinach, and white-stem salix leaf water spinach have less accumulated As content compared with other species, wherein the accumulated As content in the upper parts of the Taiwan white-stem salix leaf water spinach, Thailand white-stem salix leaf water spinach, and oil green water spinach is less than 1 mg/kg^-1(ii) a 4 varieties of white-leaf Chinese cabbage, Cajanong D-95 Chinese cabbage, green-stem leaf Chinese cabbage and Thailand bamboo leaf Chinese cabbage in Taiwan are higher in accumulated As content compared with other varieties, and the content range is 141.18-191.12 mg/kg^-1。

The transport coefficients of 4 varieties (Taiwan area large-leaf white-bone water spinach, vegetable D-95 water spinach, harbor green stem leaf water spinach and Thailand bamboo leaf water spinach) with higher accumulated As content in the test are all larger than 1, namely the content of the As in the overground part is higher than that in the underground part, wherein the transport coefficient of the water spinach except Thailand bamboo leaf is 1.08, and the content of the As in the overground part is slightly higher than that in the underground part. And the biomass of the white-leaf water spinach in Taiwan, the D-95 water spinach in vegetable growers and the green-stem leaf water spinach in harbor are higher and are all more than 10 g. Therefore, in summary, the swamp cabbage variety with relatively high As accumulation is the white bone swamp cabbage of Taiwan area, the D-95 swamp cabbage of vegetable grower, and the green stem leaf swamp cabbage of Hongkong. The transport coefficients of the 9 varieties with lower As content except for the water spinach big leaves in the North river are all below 0.01, the biomass of the Thailand water spinach, the white-pedunculate salix chinensis, the green-pedunculate lophatherum herb, the Jade-Shuaizhai water spinach and the oil water spinach are larger, and the Thailand water spinach, the white-pedunculate salix chinensis, the green-pedunculate water spinach in the Taiwan area, the Jade-Shuaizhai water spinach and the oil water spinach are the water spinach varieties with relatively low accumulated As in a comprehensive view.

Example 2 research on purification effect of indoor simulated artificial wetland treatment system on biogas slurry in pig farm

1. Method of producing a composite material

The test is carried out in an environmental ecology laboratory of an agricultural college of southern China agricultural university, a transparent glass jar with the length multiplied by the width multiplied by the height multiplied by 0.5 multiplied by 0.3 multiplied by 0.4 is taken as a container, river sand with the length multiplied by 4cm is paved at the bottom layer to fix the root system of the water spinach, and 6 water spinach with the same growth vigor (the plant height is 15cm) are planted in each glass jar. The test was carried out in two stages for a total of 30d (2016, 10-11 months), 15d each. The schematic diagram of the indoor artificial wetland simulation test site is shown in figure 1.

Wherein the compound microbial agent is prepared by mixing bacillus subtilis, saccharomycetes, lactic acid bacteria and flocculating bacteria according to the weight ratio of 7.5: 6: 3: 2.5. The powder is obtained. The total number of viable bacteria is not less than 5.0 multiplied by 10⁹cfu·g^-1。

The biogas slurry for test is from a certain pig farm in Guangdong, and is the wastewater discharged after the piggery house flushing wastewater is subjected to slag separation and solid-liquid separation and then is subjected to anaerobic biogas fermentation treatment, and the properties of the wastewater are shown in tables 4 and 5.

TABLE 4 Water quality of biogas slurry (A) in the second and first stages of the experiment

TABLE 5 Water quality of biogas slurry (B) in the second stage of the experiment

(1) The first stage is as follows: according to the weight percentage of water: biogas slurry is 3: 12L of water and 6L of biogas slurry are added according to the proportion of 1, and 8 treatments are carried out in the test. The treatment is shown in Table 6.

Table 6 indoor artificial wet land experimental design treatment group

Each treatment was repeated three times for a total of 24 treatments. The evaporated water in each glass jar was replenished with tap water every 5 days during the test to maintain a constant water sample volume per glass jar. And harvesting the overground part of the water spinach along two sections of the water surface after 15 days of treatment. TP and NH were measured in water on

days

1, 3, 5, 7, 10, 15 of the experiment₄ ⁺N content, COD content in water determined on

days

5, 10 and 15. And after the test is finished, measuring the contents of Cu, Zn and As in the plant sample and the water sample.

(2) And a second stage: 12L of biogas slurry (B) is supplemented after the overground part of the water spinach harvested on the 15 th day of the first stage is finished, and the rest treatment is unchanged. The test period was 15 days, during which the evaporating water in each glass jar was replenished with tap water every 5 days to maintain a constant water sample volume per glass jar. TP and NH were measured in water on

days

1, 5, 10, and 15 of the experiment₄ ⁺The content of N, the COD content in the water was determined on

days

1, 7 and 15. And after the test is finished, measuring the contents of Cu, Zn and As in the plant sample and the water sample.

In addition, all data below in this experiment are mean ± sem (n ═ 3), with different lower case letters in the same column indicating significant differences between treatments (p <0.05) and different upper case letters in the same row indicating significant differences at different times (p < 0.05). T1 represents a zeolite; t2 represents biochar; t3 represents zeolite + microorganism; t4 represents zeolite + chlorella; t5 represents biochar + microorganisms; t6 represents biochar + chlorella; t7 represents zeolite + biochar + microorganisms + chlorella.

2. Indoor simulation artificial wetland treatment system removes effect to TP

(1) First stage

TABLE 7 first-stage TP content variation with time (mg/L) of indoor simulated constructed wetland system

As can be seen from table 7, the removal rate of TP treated in the first stage of the indoor simulated artificial wetland treatment system is 71.60% to 92.11%, and the purification capacity is as follows: t6 (biochar + chlorella) > T7 (zeolite + biochar + microorganism + chlorella) > T5 (biochar + microorganism) > T2 (biochar) ═ T3 (zeolite + microorganism) > T4 (zeolite + chlorella) > T1 (zeolite) > CK.

Removal rate by test: t3> T4> T1, T6> T5> T2; the purification effect of the water spinach artificial wetland system enhanced by the combination of the zeolite, the biochar and the compound microbial agent is better than that of the water spinach artificial wetland system by the independent addition of the zeolite and the microbes, and the removal effects of different combinations are inconsistent, but the more the filler is added, the better the purification effect is.

(2) Second stage

TABLE 8 second-stage TP content variation with time (mg/L) of indoor simulated artificial wetland system

As can be seen from table 8, the removal rate of TP treated in each stage of the second stage of the indoor simulated artificial wetland treatment system is between 64.13% and 82.03%, and the purification capacity is as follows: t4 (zeolite + chlorella) > T6 (biochar + chlorella) > T7 (zeolite + biochar + microorganism + chlorella) > T2 (biochar) > T3 (zeolite + microorganism) > CK > T1 (zeolite) > T5 (biochar + microorganism).

In conclusion, the TP removal effect of each treatment in the first stage of the test is better than that in the second stage, the swamp cabbage wetland treatment system has a certain effect on purification of the biogas slurry TP, the adsorption effect of zeolite and biochar is reduced along with the increase of time, and the adsorption limit is certain, but the TP removal effect is kept better by adding the combination of zeolite and chlorella and the combination of biochar and chlorella to the swamp wetland system in the first stage and the second stage.

3. Indoor artificial wetland treatment system simulation NH₄ ⁺Effect of removal of-N

(1) First stage

TABLE 9 first-stage NH of indoor simulated artificial wetland system₄ ⁺The variation of N content with time (mg/L)

As can be seen from Table 9, NH was treated in each of the first stages₄ ⁺The N removal rate is between 88.01% and 99.55%, and the purification capacity is as follows: t7 (Zeolite + charcoal + microorganism + Chlorella)>T3 (Zeolite + microorganism)>T5 (charcoal and microorganism)>T6 (charcoal and chlorella)>T4 (Zeolite + Chlorella)>T1 (Zeolite)>T2 (charcoal)>CK。

(2) Second stage

TABLE 10 second-stage NH of indoor simulated artificial wetland system₄ ⁺The variation of N content with time (mg/L)

As can be seen from Table 11, each of the second stage processes NH₄ ⁺The removal rate of N is between 69.67% and 100.00%, and the purification capacity is as follows: t7 (zeolite + charcoal + microorganism + chlorella) ═ T4 (zeolite + chlorella)>T6 (charcoal and chlorella)>T3 (Zeolite + microorganism)>T5 (charcoal and microorganism)>T2 (charcoal)>T1 (Zeolite)>CK。

In summary, the treatments except T4, T6, and T7 were tested on NH in the second stage₄ ⁺The removal effect of-N is better than that of the first stage, and the rest of the treatment is to remove NH in the first stage than in the second stage₄ ⁺the-N has better removal effect, and the swamp cabbage constructed wetland has NH₄ ⁺the-N has better removal effect, and the zeolite, the biochar, the compound microbial agent and the chlorella are used in a superposition way to remove NH in the first stage and the second stage₄ ⁺The best removal is found for-N.

4. COD removing effect of indoor artificial wetland simulating treatment system

(1) First stage

TABLE 11 first-stage COD content variation with time (mg/L) of indoor simulated constructed wetland system

As shown in Table 11, the COD removal rate in each treatment of the first stage is between 80.32% and 84.11%, and the purification capacity is as follows: t7 (zeolite + biochar + microorganism + chlorella) > T5 (biochar + microorganism) > T3 (zeolite + microorganism) ═ T4 (zeolite + chlorella) ═ T6 (biochar + chlorella) > T1 (zeolite) > T2 (biochar) > CK.

(2) Second stage

TABLE 12 second-stage COD content variation with time (mg/L) of indoor simulated constructed wetland system

As can be seen from Table 12, the removal rate of COD in each treatment in the second stage was between 95.10% and 98.77%, and the purification capacity was: t6 (biochar + chlorella) > T5 (biochar + microorganism) > T1 (zeolite) > T4 (zeolite + chlorella) > T7 (zeolite + biochar + microorganism + chlorella) > T3 (zeolite + microorganism) > CK > T2 (biochar).

In conclusion, the COD removal effect of each treatment in the second stage is better than that of the first stage, the COD removal effect of each treatment in the first stage is not greatly different, and the later-stage microbial agent, chlorella and charcoal are combined for use to remove COD, so that the obvious advantages are shown.

5. Indoor simulation artificial wetland treatment system has As removal effect

(1) First stage

TABLE 13 first stage As removal Effect on Water (As: μ g/L)

As can be seen from table 13, the removal rate of As in water in each treatment of the first stage of the indoor simulated artificial wetland treatment system test was 74.61% to 83.89%, the highest removal rate was T5, and the lowest removal rate was T1.

(2) Second stage

TABLE 14 Effect of the second stage on As removal from Water (As: μ g/L)

The overlapping application of the microbial agent and the biochar and the overlapping application of the zeolite, the biochar, the microbial agent and the chlorella to the water spinach constructed wetland system show that the water spinach artificial wetland system has a good As removing effect. The removal rate of As in the water by the treatments in the second stage is between 35.38 and 74.09 percent.

In conclusion, the swamp cabbage artificial wetland system has a remarkable effect of removing heavy metal As.

6. Cabbage accumulated heavy metal content in indoor simulation artificial wetland treatment system

TABLE 15 indoor first phase water spinach overground part heavy metal content (mg/kg)

The results show that the accumulation effect of the swamp cabbage on Cu, Zn and As can be reduced by adding the zeolite and the biochar As the adsorbent into the swamp cabbage artificial wetland system, and the reduction of the accumulation effect of the zeolite on Cu is obvious.

TABLE 16 indoor second stage swamp cabbage As content (mg/kg)

As can be seen from Table 16, the accumulated As content in the overground and underground parts of the swamp cabbage of the second stage of the indoor simulated artificial wetland treatment system is As follows: underground part > aboveground part.

In conclusion, zeolite and charcoal are used As adsorbents and added into an artificial wetland system of water spinach to reduce the accumulation of heavy metals Cu, Zn and As in the water spinach, and the accumulated Cu content of the water spinach after treatment meets the standards of piglet compound feed (Cu is less than or equal to 200mg/kg) and early-stage compound feed (20 kg-60 kg body weight) (Cu is less than or equal to 150mg/kg) in the allowance of Cu in feed (GB 26419-2010); the accumulated Zn content of all the treated swamp cabbage accords with the allowance of zinc in feed (NY 929-2005); the accumulated As content of all the processed water spinach meets the feed sanitation standard (GB 13078-2001) (As is less than or equal to 10mg kg)^-1). Therefore, the swamp cabbage in the swamp cabbage artificial wetland treatment can be used as silage to return to agricultural production.

Example 3 method for efficiently purifying livestock and poultry farm wastewater by using water spinach

The site of this example was performed in an artificial wetland of a pig farm of a company in the Guangzhou Zenghain area. The wastewater discharge amount of the pig raising factory is about 500m per day³Mainly comprises pig urine, partial pig manure and pigsty washing water, belongs to high-concentration organic wastewater, and has large content of suspended matters and ammonia nitrogen. The annual average concentration of the main pollutants is: the COD is 11400 mg/L, the total phosphorus is 25mg/L, the ammonia nitrogen is 417mg/L, As is 108 mug/L, Cu is 7mg/L, and Zn is 0.8 mg/L.

The method comprises the following specific steps:

in the starting operation period, the mixture of the biochar and the chlorella is added into the artificial wetland in the proportion of 0.1, 1, 5, 10 and 20g/L (the mass ratio of the biochar to the chlorella is 50: 3). And planting the white-bone water spinach in the Taiwan area on the artificial wet land. In the operation process, the organic wastewater generated by solid-liquid separation of domestic sewage and pig farm waste enters a black film methane tank, a DST microorganism selection pond anaerobic fermentation tank and a DST advanced treatment biochemical tank in sequence after pH value adjustment, and then enters the artificial wetland, and the sewage stays in the artificial wetland for 10 days in a hydraulic power manner. And the water treated by the artificial wetland enters a flocculation sedimentation tank for sedimentation treatment, and then enters a drainage tank through an MBR membrane and RO combined system. Through the interaction among water spinach, biochar, chlorella and microorganisms in water, the contents of pollutants such As heavy metal (mainly As), organic matters, nitrogen, phosphorus and the like in the water body are effectively reduced through the processes of adsorption, ion exchange, plant absorption and transfer and the like.

Finally, measuring the water quality indexes of Total Phosphorus (TP) and ammonia Nitrogen (NH) of the effluent of a drainage pool of the mixture of the biochar and the chlorella added according to the proportion of 0.1, 1, 5, 10 and 20g/L₄ ⁺N) and COD both reach the discharge standard of pollutants for livestock and poultry breeding (DB 44/613-2009), and the content indexes of As, Cu and Zn all reach the discharge standard of Integrated wastewater (GB 8978-88). Wherein the mixture of the biochar and the chlorella added according to the proportion of 5-15 g/L has better treatment effect.

The MBR membrane and RO combined system comprises an MBR membrane system and an RO system. Wherein MBR membrane system includes that one set of MBR membrane is automatic washes and one set of MBR membrane separation chemical cleaning system, and MBR membrane separation chemical cleaning system includes that a washing medical kit, a backwash pump, corresponding instrument and connecting pipe fitting constitute, when the membrane module received the pollution, can carry out the chemical cleaning of MBR membrane system with it. The cleaning mode is pulse cleaning, and dirt and pollutants on the surface of the membrane are thoroughly removed by using cleaning liquid and water pressure change. The MBR membrane can adopt a hollow fiber membrane, and can effectively intercept the backflow of bacteria and suspended matters through the high-efficiency interception function of the membrane, so as to effectively remove ammonia nitrogen; meanwhile, macromolecular organic matters which are difficult to degrade can be intercepted, and the retention time of the macromolecular organic matters in the reactor is prolonged, so that the macromolecular organic matters are degraded to the maximum extent. The excess sludge is discharged periodically by an excess sludge pump in the membrane area, and the concentration and the sludge age of the activated sludge in the system can be controlled. The RO system, which is a reverse osmosis device as one of the common devices for wastewater treatment, adopts an advanced reverse osmosis membrane separation technology, is an important device for removing most of impurities such as salinity, bacteria, viruses and the like in raw water, and is also a key treatment link for ensuring the quality of effluent water of the device.

The invention has low construction cost, convenient operation and management, low treatment cost and can greatly save investment; and swamp cabbage is selected as wetland plants, so that the removal effect on arsenic, organic matters, nitrogen and phosphorus is good.

Example 4 method for efficiently purifying livestock and poultry farm wastewater by using water spinach

The method comprises the following specific steps:

in the starting operation period, a mixture of zeolite and chlorella (the mass ratio of the zeolite to the chlorella is 150: 3) is added into the artificial wetland according to the proportion of 5 g/L. And planting white leaf swamp cabbage, vegetable farmer D-95 swamp cabbage and green stem leaf swamp cabbage in Taiwan on artificial wet land. In the operation process, the organic wastewater generated by solid-liquid separation of domestic sewage and pig farm waste enters a black film methane tank, a DST microorganism selection pond anaerobic fermentation tank and a DST advanced treatment biochemical tank in sequence after pH value adjustment, and then enters the artificial wetland, and the sewage stays in the artificial wetland for 30 days in a hydraulic power manner. And the water treated by the artificial wetland enters a flocculation sedimentation tank for sedimentation treatment, and then enters a drainage tank through an MBR membrane and RO combined system. Through the interaction among water spinach, biochar, chlorella and microorganisms in water, the contents of pollutants such As heavy metal (mainly As), organic matters, nitrogen, phosphorus and the like in the water body are effectively reduced through the processes of adsorption, ion exchange, plant absorption and transfer and the like.

Finally, the effluent quality indexes of the drainage pool of the mixture of the zeolite and the chlorella added according to the proportion of 5g/L are measured, namely Total Phosphorus (TP) and ammonia Nitrogen (NH)₄ ⁺N) and COD meet the discharge standard of pollutants for livestock and poultry breeding (DB 44/613-2009), and the content indexes of As, Cu and Zn meet the discharge standard of Integrated wastewater (GB 8978-88).

Example 5A method for efficiently purifying livestock and poultry farm wastewater by using water spinach

The method comprises the following specific steps:

planting the white-bone water spinach in Taiwan area on the artificial wet land. In the operation process, the organic wastewater generated by solid-liquid separation of domestic sewage and pig farm waste enters a black film methane tank, a DST microorganism selection pond anaerobic fermentation tank and a DST advanced treatment biochemical tank in sequence after pH value adjustment, and then enters the artificial wetland, and the sewage stays in the artificial wetland for 15 days in a hydraulic power manner. And the water treated by the artificial wetland enters a flocculation sedimentation tank for sedimentation treatment, and then enters a drainage tank through an MBR membrane and RO combined system.

As a result, the artificial wetland is planted with the large-leaf white bones in the Taiwan area, so that the content of pollutants such As heavy metals (mainly As), organic matters, nitrogen, phosphorus and the like in the water body can be effectively reduced. Finally, the effluent quality indexes of the drainage pool, namely Total Phosphorus (TP) and ammonia Nitrogen (NH), are measured₄ ⁺N) and COD meet the discharge standard of pollutants for livestock and poultry breeding (DB 44/613-2009), and the content indexes of As, Cu and Zn meet the discharge standard of Integrated wastewater (GB 8978-88).

In the embodiment of the invention, the treatment time of the sewage in the black film methane tank, the DST microorganism selection pond anaerobic fermentation tank, the DST advanced treatment biochemical tank and the flocculation sedimentation tank can be properly adjusted by technical personnel in the field of aquaculture sewage treatment according to the actual pollution condition.

The applicant declares that the above detailed description is a preferred embodiment described for the convenience of understanding the present invention, but the present invention is not limited to the above embodiment, i.e. it does not mean that the present invention must be implemented by means of the above embodiment. It will be apparent to those skilled in the art that any modification of the present invention, equivalent substitutions of selected materials and additions of auxiliary components, selection of specific modes and the like, which are within the scope and disclosure of the present invention, are contemplated by the present invention.

Claims

1. A method for efficiently purifying sewage of a livestock and poultry farm by using water spinach is characterized by comprising the following steps:

2. The method as claimed in claim 1, wherein the variety of the water spinach is selected from one or more of green stem leaf water spinach of harbor species, white bone water spinach of Taiwan region, D-95 water spinach of vegetable grower, Thailand leaf water spinach, Tibet leaf water spinach of Thailand, white bone water spinach of harbor species, middle leaf water spinach of Thailand, pure green leaf water spinach of Guangdong, green bone leaf water spinach of Taigu, water spinach of Jiangxi, big leaf water spinach of Hebei, 999 green bone leaf water spinach of Salix purpurea, green leaf water spinach of Yushui, white stem leaf water spinach of Taiwan region, white bone leaf water spinach of Taiwan region, green stem leaf water spinach of Taiwan region, white stem leaf water spinach of Thailand region or oil green water spinach of Taiwan region.

3. The method as claimed in claim 2, wherein the variety of the water spinach is one or more selected from the group consisting of Taiwan white-leaf water spinach, Cajanong D-95 water spinach, Hongkong green-leaf water spinach and Thailand bamboo leaf water spinach.

4. The method according to claim 3, wherein S1 is added with filler selected from one or more of zeolite, charcoal, compound microbial agent or chlorella.

5. The method according to claim 4, wherein the filler is selected from a mixture of biochar and chlorella, or a mixture of zeolite, biochar, microorganisms and chlorella, or a mixture of biochar and microorganisms, or a mixture of zeolite and microorganisms.

6. The method according to claim 5, wherein in the mixture of the biochar and the chlorella, the mass ratio of the biochar to the chlorella is 50-150: 3; in the mixture of the zeolite and the chlorella, the mass ratio of the zeolite to the chlorella is 50-150: 3; in the mixture of the zeolite, the biochar, the microorganisms and the chlorella, the mass ratio of the zeolite to the biochar to the microorganisms to the chlorella is 50-150: 50-150: 1: 3; in the mixture of the biochar and the microorganisms, the mass ratio of the biochar to the microorganisms is 50-150: 1; in the mixture of the zeolite and the microorganism, the mass ratio of the zeolite to the microorganism is 50-150: 1.

7. the method of claim 4, wherein the complex microbial agents comprise Bacillus subtilis, yeast, lactic acid bacteria, and flocculating bacteria.

8. The method according to claim 7, wherein the compound microbial agent is prepared by mixing bacillus subtilis, saccharomycetes, lactic acid bacteria and flocculating bacteria according to the weight ratio of 5-10: 2-10: 1-6: 1-5; the total number of viable bacteria is not less than 5.0 multiplied by 10⁹cfu·g^-1。

9. The method according to claim 4, wherein the filler is added in an amount of 0.1 to 20 g/L.

10. The method according to claim 1, wherein the solid manure residues produced by the solid-liquid separation in the step S1 are sent to a storage yard for organic fertilizer nutrient recovery or returning to the field for utilization or sent to a fermentation plant for treatment.