Device for removing organophosphorus ester in sewage by iron-containing matrix reinforced artificial wetland

Abstract

The utility model belongs to the technical field of organic pollutant removal, and provides a device for removing organophosphate in sewage by an iron-containing substrate reinforced artificial wetland, the iron-containing substrate comprises four layers, namely a gravel layer, a zeolite layer, a zeolite buffer layer and a quartz sand layer from bottom to top in sequence; and the zeolite layer is doped with an iron matrix. According to the device for removing the organophosphorus ester in the sewage by the iron-containing substrate reinforced artificial wetland, the reinforced removal of organophosphorus ester pollutants can be realized, the pollutant removal capability of an artificial wetland system is further effectively improved, and the ecological risk level of OPEs to a receiving water body is relieved; the device for removing the organophosphorus ester in the sewage by the iron-containing substrate reinforced constructed wetland is relatively simple in structure and convenient to construct, and has no other special requirements on the device in the process of removing the organophosphorus ester in the sewage, so that the operation cost can be effectively reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to organic pollutant removal technical field especially relates to a device that iron -containing substrate intensifies constructed wetland and removes organic phosphate in sewage. BACKGROUND

[0002] Organophosphates (OPEs) are a class of synthetic phosphoric acid derivatives, widely used as flame retardants, plasticizers and lubricants in products such as furniture, textiles, electronics, baby toys, building materials, floor polish and defoaming stabilizers. However, OPEs are often applied to material products in the form of physical rather than chemical bonds, and are easily released into the environment during production, use and disposal. In addition, the oxidation of phosphite antioxidants in plastic products is also an important source of OPEs in the environment. Because of their neurotoxicity, carcinogenicity, teratogenicity, developmental toxicity and endocrine disrupting toxicity, the use of tris (2-chloroethyl) phosphate (TCEP) and tris (2-chloroisopropyl) phosphate (TCIPP) has been restricted, and TCEP and triphenyl phosphate (TPhP) have also been listed as priority control chemicals. At present, OPEs have been widely detected in various environmental media around the world, and have also been detected in human placenta, breast milk and blood. Due to the high stability of OPEs (especially chlorinated OPEs), the removal rate of traditional sewage treatment plant treatment process is very low, and the effluent can still reach dozens of μg / L, becoming an important source of surface water. Commonly used advanced treatment technologies for reclaimed water, such as adsorption, membrane filtration, advanced oxidation and other physical and chemical technologies, can remove OPEs in water to some extent, but the removal effect is limited, the cost is high, and secondary pollution problems such as oxidation intermediates are easy to cause, which is difficult to popularize and apply in low concentration watershed water environment.

[0003] Compared with other technologies, constructed wetlands are artificially constructed to simulate natural ecosystems, relying on the combined action of substrate, microorganisms and plants to effectively remove various pollutants in wastewater, especially microorganisms play a crucial role in wastewater purification, with the characteristics of green, economic, simple operation and good landscape benefits. Among them, the substrate is an important carrier of microorganisms in constructed wetlands, which plays a direct and indirect role in water purification and can significantly affect the structure and abundance level of microorganisms. Usually, iron-containing substrate can not only act as an electron acceptor / donor to promote the growth and metabolism of microorganisms, but also act as an electron transfer material to mediate the electron transfer between microorganisms, and act as an electron storage medium for microbial extracellular respiration to promote the growth and metabolism of microorganisms, thereby enhancing the removal of pollutants. In addition, iron substrate is also a strong adsorbent of inorganic phosphorus and organic phosphorus in phosphorus biogeochemical cycle, and can also catalyze the dephosphorylation reaction of organic phosphorus through abiotic processes to generate inorganic phosphate, and the catalytic reactivity of various organic phosphorus compounds is significantly enhanced compared with silicate and aluminosilicate minerals.

[0004] Therefore, the device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance. Content of the utility model

[0005] The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance.

[0006] In order to realize the above-mentioned utility model purposes, the utility model provides the following technical scheme:

[0007] The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance.

[0008] As a preferred, the device is constructed by using stainless steel column, the water inlet of the device is at the lower part, and the water outlet is at the upper part; the middle of the device is provided with a porous stainless steel pipe, and the diameter of the porous stainless steel pipe is 2.8-3.2 cm.

[0009] As a preferred, the height of the gravel layer is 8-12 cm, the height of the zeolite layer is 27-33 cm, the height of the zeolite buffer layer is 8-12 cm, and the height of the quartz sand layer is 8-12 cm.

[0010] As a preferred, the iron substrate is iron-carbon filler.

[0011] The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance.

[0012] 1) The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland can realize the reinforced removal of organic phosphate pollutants, further effectively improve the pollutant removal capacity of the artificial wetland system, and relieve the ecological risk level of OPEs to the receiving water body.

[0013] 2) The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has relatively simple structure, is convenient to build, and has no other special requirements for the device in the process of removing organic phosphates in sewage, so that the operation cost can be effectively reduced. DRAWINGS

[0014] Figure 1 The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance.

[0015] Figure 2 The device for removing organic phosphates in sewage by using iron-containing substrate reinforced artificial wetland has important significance.

[0016] Figure 3 Microbial community composition in the device for removing organic phosphates in sewage in the constructed wetland of examples 1, 2 and comparative example 1. DETAILED DESCRIPTION

[0017] The utility model provides a device for removing organic phosphates in sewage in the constructed wetland of iron-containing substrate, and the iron-containing substrate comprises four layers, which are gravel layer, zeolite layer, zeolite buffer layer and quartz sand layer from bottom to top in sequence; the zeolite layer is doped with iron substrate.

[0018] In the utility model, the device is constructed by stainless steel column, the water inlet of the device is at the lower part, and the water outlet is at the upper part; a perforated stainless steel pipe is arranged in the middle of the device, and the diameter of the perforated stainless steel pipe is 2.8-3.2 cm.

[0019] In the utility model, the height of the gravel layer is 8-12 cm, the height of the zeolite layer is 27-33 cm, the height of the zeolite buffer layer is 8-12 cm, and the height of the quartz sand layer is 8-12 cm.

[0020] In the utility model, the iron substrate is iron-carbon filler.

[0021] The technical solutions provided by the utility model will be described in detail in combination with examples, but they should not be understood as limitations on the protection scope of the utility model.

[0022] The iron-carbon filler is purchased from Henan Bizhe Environmental Protection Technology Co., Ltd., and the mass content of C element in the iron-carbon filler is 40%, the mass content of Fe element is 30%, the mass content of Al element is 10%, and the rest is conventional components in the raw materials for preparing the iron-carbon filler and inevitable impurities.

[0023] Example 1

[0024] A device for removing organic phosphates in sewage in the constructed wetland of iron-containing substrate is constructed by a stainless steel column with an inner diameter of 15 cm and a height of 70 cm. The aquatic plants are yellow flag, and the density is 200 plants / m 2The substrates are evenly and regularly planted, and the substrates include four layers from bottom to top, which are gravel layer, zeolite layer, zeolite buffer layer and quartz sand layer in sequence; the height of the gravel layer is 10 cm, and the particle size of the gravel is 22 mm; the height of the zeolite layer is 30 cm, the natural zeolite in the zeolite layer is doped with iron-carbon filler, the particle size of the natural zeolite and the iron-carbon filler is 10 mm, and the volume ratio of the natural zeolite to the iron-carbon filler is 1:1; the height of the zeolite buffer layer (only natural zeolite) is 10 cm, and the particle size of the natural zeolite is 6 mm; the height of the quartz sand layer is 10 cm, and the particle size of the quartz sand is 3 mm. The water in the device adopts the way of entering from the bottom and flowing out from the top, the water inlet is arranged at the lower part of the device, the water outlet is arranged at the upper part of the device, and a porous stainless steel pipe with a diameter of 3 cm (the pore size of the porous stainless steel pipe is 4 mm, and 9 holes are opened every 3 cm) is arranged in the middle of the device, so that the physicochemical parameters of different depth layers can be monitored in situ.

[0025] Example 2

[0026] In example 1, the volume ratio of the natural zeolite to the iron-carbon filler is changed from 1:1 to 1:0.5, and the other conditions are the same as those in example 1.

[0027] The device diagram of the iron-containing substrate enhanced constructed wetland for removing organic phosphates in wastewater in example 1 and example 2 is shown in Figure 1 .

[0028] Example 3

[0029] An iron-containing substrate enhanced constructed wetland device for removing organic phosphates in wastewater is constructed by using a stainless steel column with an inner diameter of 15 cm and a height of 66 cm. The aquatic plants are yellow flag, and the density is 200 plants / m 2 The substrates are evenly and regularly planted, and the substrates include four layers from bottom to top, which are gravel layer, zeolite layer, zeolite buffer layer and quartz sand layer in sequence; the height of the gravel layer is 10 cm, and the particle size of the gravel is 22 mm; the height of the zeolite layer is 30 cm, the natural zeolite in the zeolite layer is doped with iron-carbon filler, the particle size of the natural zeolite and the iron-carbon filler is 10 mm, and the volume ratio of the natural zeolite to the iron-carbon filler is 1:1; the height of the zeolite buffer layer (only natural zeolite) is 10 cm, and the particle size of the natural zeolite is 6 mm; the height of the quartz sand layer is 10 cm, and the particle size of the quartz sand is 3 mm. The water in the device adopts the way of entering from the bottom and flowing out from the top, the water inlet is arranged at the lower part of the device, the water outlet is arranged at the upper part of the device, and a porous stainless steel pipe with a diameter of 3 cm (the pore size of the porous stainless steel pipe is 4 mm, and 9 holes are opened every 3 cm) is arranged in the middle of the device, so that the physicochemical parameters of different depth layers can be monitored in situ.

[0030] Example 4

[0031] A stainless steel column with an inner diameter of 15 cm and a height of 72 cm was used to construct an iron-containing substrate enhanced constructed wetland for removing organic phosphates in sewage. The aquatic plants were Juncus effusus, and 200 plants per m 2 were planted in a uniform interval. The substrate included four layers, from bottom to top, in order: gravel layer, zeolite layer, zeolite buffer layer, and quartz sand layer. The height of the gravel layer was 11 cm, and the particle size of the gravel was 25 mm. The height of the zeolite layer was 29 cm, and the natural zeolite in the zeolite layer was mixed with iron-carbon filler. The particle size of the natural zeolite and the iron-carbon filler was 12 mm, and the volume ratio of the natural zeolite to the iron-carbon filler was 1:0.8. The height of the zeolite buffer layer was 11 cm, and the particle size of the natural zeolite was 7 mm. The height of the quartz sand layer was 11 cm, and the particle size of the quartz sand was 3.5 mm. The water in the device was introduced from the bottom to the top. The inlet was located at the lower part of the device, and the outlet was located at the upper part of the device. A porous stainless steel pipe with a diameter of 3.1 cm (the hole diameter of the pipe was 4.5 mm, and 8 holes were opened every 3 cm) was placed in the middle of the device to facilitate in-situ monitoring of the physicochemical parameters at different depths.

[0032] Comparative Example 1

[0033] The iron-carbon filler in the zeolite layer of Example 1 was omitted, and the other conditions were the same as those of Example 1.

[0034] The devices of Examples 1 and 2 and Comparative Example 1 were used to remove organic phosphate compounds in sewage. The specific process was as follows: the sewage inlet of the device used the effluent from a sewage treatment plant with level A (GB 18918-2002). In the sewage, the initial concentrations of tris(2-chloroethyl) phosphate (TCEP), tris(1-chloro-2-propyl) phosphate (TCIPP), tri-n-butyl phosphate (TNBP), tris(2-ethylhexyl) phosphate (TEHP), and triphenyl phosphate (TPHP) were all 1 μg / L. The sewage containing organic phosphate esters (OPEs) was introduced into the devices of the examples and the comparative example by a peristaltic pump. The water passed through the gravel layer, the zeolite layer, the zeolite buffer layer, and the quartz sand layer from bottom to top. The hydraulic retention time (HRT) was set to 1.5 days, and the influent load was 0.2 m 3 / (m 2 ·d). The purified water was discharged through the drain pipe, and the OPEs in the influent and effluent were quantitatively tracked and detected.

[0035] After the devices of Examples 1, 2, and Comparative Example 1 were stably operated for 120 days, the contents of TCEP, TCIPP, TNBP, TEHP, TPHP, and total OPEs were detected, and the removal rates were calculated. The effluent concentrations and removal rates of organic phosphates in the constructed wetlands for removing organic phosphates in sewage of Examples 1, 2, and Comparative Example 1 are shown in Table 1. Figure 2The removal rates of TCEP, TCIPP, TNBP, TEHP, TPHP and total OPEs (ΣOPEs) in wastewater by the device of Comparative Example 1 were 4.4±6.2%, 25.3±8.4%, 76.6±6.2%, 70.5±16.2%, 68.0±6.2% and 46.9±4.4%, respectively, while the removal rates of TCEP, TCIPP, TNBP, TEHP, TPHP and total OPEs (ΣOPEs) in wastewater by the device of Example 1 were 57.0±9.0%, 46.4±8.7%, 90.9±3.1%, 73.2±15.2%, 74.3±7.0% and 65.7±4.5%, respectively. Compared with Comparative Example 1, the removal rates of two chlorine-containing TCEP and TCIPP in Example 1 increased by the largest amount, and the removal rates of TCEP and TCIPP increased by 52.6% and 21.1%, respectively, which were 13.0 times and 1.8 times the removal rates of Comparative Example 1. The removal rate of ΣOPEs increased by 18.8%. The change in the removal rate of Example 1 relative to Example 2 was small, and the removal rate of ΣOPEs increased by 4.9%, while the removal rates of TCEP and TCIPP increased by 14.3% and 6.7%. This result shows that the volume ratio of natural zeolite and iron-carbon filler in the device for removing organic phosphates in wastewater by iron-containing substrate enhanced constructed wetland is 1:1 or 1:0.5, which has a good effect on the removal of OPEs in wastewater, and the removal rate of chlorine-containing OPEs is more significantly improved.

[0036] The microbial community composition in the device for removing organic phosphates in wastewater by the constructed wetland of Example 1, 2 and Comparative Example 1 is shown in Table 2. Figure 3 As shown in Table 2, the doping of iron substrate changes the microbial community structure composition of the substrate of the constructed wetland. Figure 3

[0037] The above only describes preferred embodiments of the present application, and it should be pointed out that for ordinary skilled persons in the technical field, some improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be regarded as the protection scope of the present application.​

Claims

1. An apparatus for removing organophosphates from wastewater in an iron-containing substrate enhanced constructed wetland, characterized in that, The iron-containing substrate comprises four layers, from bottom to top, gravel layer, zeolite layer, zeolite buffer layer and quartz sand layer; the iron-containing substrate is doped in the zeolite layer.

2. The apparatus of claim 1, wherein, The device is constructed by a stainless steel column, the water inlet is at the lower part and the water outlet is at the upper part; a porous stainless steel pipe is arranged in the middle of the device, and the diameter of the porous stainless steel pipe is 2.8-3.2 cm.

3. The apparatus of claim 1 or 2, wherein, The height of the gravel layer is 8-12 cm, the height of the zeolite layer is 27-33 cm, the height of the zeolite buffer layer is 8-12 cm, and the height of the quartz sand layer is 8-12 cm.

4. The apparatus of claim 3, wherein, The iron-containing substrate is iron-carbon filler.

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