CN113603256A - Domestic sewage treatment agent capable of efficiently removing phosphorus and preparation method thereof - Google Patents
Domestic sewage treatment agent capable of efficiently removing phosphorus and preparation method thereof Download PDFInfo
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- CN113603256A CN113603256A CN202110893886.7A CN202110893886A CN113603256A CN 113603256 A CN113603256 A CN 113603256A CN 202110893886 A CN202110893886 A CN 202110893886A CN 113603256 A CN113603256 A CN 113603256A
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- wtr
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- solution
- sodium alginate
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- 239000010865 sewage Substances 0.000 title claims abstract description 134
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 title claims abstract description 106
- 239000011574 phosphorus Substances 0.000 title claims abstract description 106
- 229910052698 phosphorus Inorganic materials 0.000 title claims abstract description 106
- 239000003795 chemical substances by application Substances 0.000 title claims abstract description 75
- 238000002360 preparation method Methods 0.000 title claims abstract description 34
- IXPNQXFRVYWDDI-UHFFFAOYSA-N 1-methyl-2,4-dioxo-1,3-diazinane-5-carboximidamide Chemical compound CN1CC(C(N)=N)C(=O)NC1=O IXPNQXFRVYWDDI-UHFFFAOYSA-N 0.000 claims abstract description 96
- 239000000661 sodium alginate Substances 0.000 claims abstract description 95
- 235000010413 sodium alginate Nutrition 0.000 claims abstract description 95
- 229940005550 sodium alginate Drugs 0.000 claims abstract description 95
- 239000011324 bead Substances 0.000 claims abstract description 88
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 claims abstract description 42
- 239000000843 powder Substances 0.000 claims abstract description 33
- 239000011790 ferrous sulphate Substances 0.000 claims abstract description 26
- 235000003891 ferrous sulphate Nutrition 0.000 claims abstract description 26
- 229910000359 iron(II) sulfate Inorganic materials 0.000 claims abstract description 26
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 21
- 239000008394 flocculating agent Substances 0.000 claims abstract description 12
- 239000002738 chelating agent Substances 0.000 claims abstract description 9
- BAUYGSIQEAFULO-UHFFFAOYSA-L iron(2+) sulfate (anhydrous) Chemical compound [Fe+2].[O-]S([O-])(=O)=O BAUYGSIQEAFULO-UHFFFAOYSA-L 0.000 claims abstract 3
- 239000000243 solution Substances 0.000 claims description 84
- 238000003756 stirring Methods 0.000 claims description 58
- 229910021642 ultra pure water Inorganic materials 0.000 claims description 46
- 239000012498 ultrapure water Substances 0.000 claims description 46
- 229910052938 sodium sulfate Inorganic materials 0.000 claims description 40
- 239000007832 Na2SO4 Substances 0.000 claims description 37
- 238000006243 chemical reaction Methods 0.000 claims description 37
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 238000000034 method Methods 0.000 claims description 31
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 24
- 230000008569 process Effects 0.000 claims description 21
- 238000001035 drying Methods 0.000 claims description 20
- 229960001126 alginic acid Drugs 0.000 claims description 17
- 235000010443 alginic acid Nutrition 0.000 claims description 17
- 239000000783 alginic acid Substances 0.000 claims description 17
- 229920000615 alginic acid Polymers 0.000 claims description 17
- 150000004781 alginic acids Chemical group 0.000 claims description 17
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 claims description 13
- 239000007788 liquid Substances 0.000 claims description 12
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 12
- 238000002156 mixing Methods 0.000 claims description 11
- 238000004140 cleaning Methods 0.000 claims description 10
- 238000004132 cross linking Methods 0.000 claims description 10
- 239000011259 mixed solution Substances 0.000 claims description 10
- 239000000463 material Substances 0.000 claims description 9
- 239000011541 reaction mixture Substances 0.000 claims description 9
- 238000001816 cooling Methods 0.000 claims description 7
- 239000000203 mixture Substances 0.000 claims description 3
- 238000001179 sorption measurement Methods 0.000 abstract description 28
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 abstract description 18
- 150000003839 salts Chemical class 0.000 abstract description 10
- 230000004048 modification Effects 0.000 abstract description 5
- 238000012986 modification Methods 0.000 abstract description 5
- 230000000694 effects Effects 0.000 description 39
- SURQXAFEQWPFPV-UHFFFAOYSA-L iron(2+) sulfate heptahydrate Chemical compound O.O.O.O.O.O.O.[Fe+2].[O-]S([O-])(=O)=O SURQXAFEQWPFPV-UHFFFAOYSA-L 0.000 description 24
- 238000002474 experimental method Methods 0.000 description 21
- 239000011325 microbead Substances 0.000 description 17
- 239000010802 sludge Substances 0.000 description 17
- 239000002994 raw material Substances 0.000 description 14
- 239000002245 particle Substances 0.000 description 13
- 239000007789 gas Substances 0.000 description 10
- 239000000706 filtrate Substances 0.000 description 8
- 239000006228 supernatant Substances 0.000 description 8
- 150000002500 ions Chemical class 0.000 description 7
- 230000008929 regeneration Effects 0.000 description 7
- 238000011069 regeneration method Methods 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 229910001385 heavy metal Inorganic materials 0.000 description 6
- 239000011575 calcium Substances 0.000 description 5
- 238000005189 flocculation Methods 0.000 description 5
- 229910052742 iron Inorganic materials 0.000 description 5
- 229910021645 metal ion Inorganic materials 0.000 description 5
- 238000003825 pressing Methods 0.000 description 5
- 230000016615 flocculation Effects 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- 239000011734 sodium Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 238000009210 therapy by ultrasound Methods 0.000 description 4
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 3
- 238000009388 chemical precipitation Methods 0.000 description 3
- 238000003795 desorption Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- -1 iron ions Chemical class 0.000 description 3
- 239000003446 ligand Substances 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 230000002572 peristaltic effect Effects 0.000 description 3
- 239000011148 porous material Substances 0.000 description 3
- 238000012216 screening Methods 0.000 description 3
- 235000011152 sodium sulphate Nutrition 0.000 description 3
- 238000003860 storage Methods 0.000 description 3
- 238000012795 verification Methods 0.000 description 3
- 238000005303 weighing Methods 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 150000001768 cations Chemical class 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 239000003431 cross linking reagent Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000005342 ion exchange Methods 0.000 description 2
- 150000002505 iron Chemical class 0.000 description 2
- RUTXIHLAWFEWGM-UHFFFAOYSA-H iron(3+) sulfate Chemical compound [Fe+3].[Fe+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O RUTXIHLAWFEWGM-UHFFFAOYSA-H 0.000 description 2
- 229910000360 iron(III) sulfate Inorganic materials 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000004064 recycling Methods 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 239000011550 stock solution Substances 0.000 description 2
- 238000004065 wastewater treatment Methods 0.000 description 2
- URRHWTYOQNLUKY-UHFFFAOYSA-N [AlH3].[P] Chemical compound [AlH3].[P] URRHWTYOQNLUKY-UHFFFAOYSA-N 0.000 description 1
- ZQBZAOZWBKABNC-UHFFFAOYSA-N [P].[Ca] Chemical compound [P].[Ca] ZQBZAOZWBKABNC-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- REDXJYDRNCIFBQ-UHFFFAOYSA-N aluminium(3+) Chemical compound [Al+3] REDXJYDRNCIFBQ-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 230000009920 chelation Effects 0.000 description 1
- 239000000701 coagulant Substances 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 230000002860 competitive effect Effects 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 235000020774 essential nutrients Nutrition 0.000 description 1
- 238000012851 eutrophication Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 238000004952 furnace firing Methods 0.000 description 1
- 230000036541 health Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 239000003094 microcapsule Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- DPTATFGPDCLUTF-UHFFFAOYSA-N phosphanylidyneiron Chemical compound [Fe]#P DPTATFGPDCLUTF-UHFFFAOYSA-N 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 239000012779 reinforcing material Substances 0.000 description 1
- 238000011268 retreatment Methods 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 239000010801 sewage sludge Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000007711 solidification Methods 0.000 description 1
- 230000008023 solidification Effects 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/58—Treatment of water, waste water, or sewage by removing specified dissolved compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/105—Phosphorus compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Hydrology & Water Resources (AREA)
- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Water Treatment By Sorption (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
The invention discloses a domestic sewage treatment agent for efficiently removing phosphorus and a preparation method thereof, and relates to the technical field of sewage treatment. The domestic sewage treatment agent for efficient phosphorus removal comprises, by weight, 10-40 parts of modified WTR sodium alginate beads, 30-90 parts of a flocculating agent, 3-20 parts of a chelating agent, 3-10 parts of ferrous sulfate, 1-3 parts of citric acid and 3-10 parts of reduced iron powder. The modified WTR has over 70 percent of phosphorus adsorption rate through salt modification and roasting; the prepared modified WTR sodium alginate bead can be desorbed by NaOH solution and has good reusability; the domestic sewage treatment agent using the modified WTR sodium alginate bead has a phosphorus adsorption rate of more than 95%.
Description
Technical Field
The invention relates to the technical field of sewage treatment, in particular to a modified WTR, a preparation method and a domestic sewage treatment agent with the modified WTR sodium alginate bead and high-efficiency phosphorus removal function.
Background
Phosphorus contained in domestic urban domestic sewage is a common phenomenon. Although phosphorus is an essential nutrient substance for organisms and has low toxicity, the water body eutrophication is caused by the large discharge of the phosphorus-containing sewage, and the water body environment is deteriorated. Even if the average phosphorus content in the domestic sewage is in a lower interval, the sewage which is not subjected to phosphorus removal treatment is directly discharged due to large sewage amount, and the surrounding environment is seriously damaged in the long run.
At present, the mainstream sewage phosphorus removal method is that iron salt phosphorus removal agent, calcium salt phosphorus removal agent and aluminum salt phosphorus removal agent are added, but because of the characteristic of high phosphorus reverse solubility, the phosphorus content of supernatant liquid obtained by pressing and filtering a plate frame in the sewage treatment process is higher, so that the total phosphorus content of the treated sewage before being discharged is still higher. The mud cake caused by high phosphorus insolubility releases a large amount of phosphorus again in the filter pressing process, so that the phosphorus removing agent with better phosphorus removing effect in some sewage treatment stages has weak scale removing effect in practical application. Therefore, the treatment of sewage to achieve the objective of scale removal has problems of high treatment cost and difficulty in treatment.
Disclosure of Invention
The invention aims to provide a domestic sewage treatment agent for efficiently removing phosphorus. The treatment agent can meet the treatment requirements of decomposing organic matters, reducing chemical oxygen demand, separating solid and liquid, settling suspended particles and other conventional domestic sewage by using the treatment agent alone, and other agents are not required to be mixed and added in the treatment process.
The domestic sewage treatment agent (hereinafter referred to as sewage treatment agent) for efficiently removing phosphorus comprises 10-40 parts by weight of modified WTR sodium alginate bead, 30-90 parts by weight of flocculant, 3-20 parts by weight of chelating agent, 3-10 parts by weight of ferrous sulfate, 1-3 parts by weight of citric acid and 3-10 parts by weight of reduced iron powder.
Further, the flocculant comprises 20-50 parts by weight of aluminum sulfate and 10-40 parts by weight of sodium carbonate.
Further, the chelating agent is alginic acid.
Furthermore, the ferrous sulfate is ferrous sulfate heptahydrate and is light blue green crystal particles, and the particles can be oxidized into brown yellow ferric sulfate particles in humid air, so that the brown yellow ferric sulfate particles are dried and stored as much as possible, and powder is prevented from being oxidized, and part of reducibility of the powder is lost.
Further, the modified WTR sodium alginate bead is a microcapsule ball with the diameter of 0.5-3mm, which is formed by embedding and fixing modified WTR powder modified by salt and roasted by heat under the gel action of Sodium Alginate (SA) and ferrous sulfate.
Further, the preparation method of the modified WTR sodium alginate bead is divided into two parts, namely, the salt modification and roasting are carried out on the WTR to obtain the modified WTR. And secondly, embedding and fixing the modified WTR by using sodium alginate as an embedding agent, and preparing a micro-colloidal sphere to obtain the modified WTR sodium alginate bead. Wherein, sodium sulfate is used as the salt for modifying the salt, ferrous sulfate is used as the cross-linking agent of the sodium alginate solution, and the embedding and fixing of the modified WTR are involved.
The preparation method of the modified WTR specifically comprises the following steps:
s1: adding WTR to Na2S04Stirring and reacting in the solution for 6-8 h; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20-30, Na2SO4The concentration of the solution is 0.1-0.5 mol/L;
s2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying WTR filter material at 90-110 deg.C, drying and adding N2Roasting for 3-5h under the environment of 350-450 ℃ under the protection of gas, and cooling to obtain the modified WTR.
Preferably, in the step S1, the stirring reaction is specifically performed by first slowly stirring for 1-3min, and then stirring at a rotation speed of 150-.
Preferably, in step S3, the drying time is 10-12 hours.
Preferably, in step S3, N is in a muffle furnace, a tube furnace2Roasting for 3-5h at the temperature of 350-450 ℃ under the protection of gas.
WTR (Water treatment residues) is water treatment residue and comprises 25-35% of Si element, 60-70g/kg of Al element, 15-25g/kg of Ca element and 200-250g/kg of Fe element by mass fraction. Such as iron-containing sludge of a water supply plant of a water works.
In the roasting process, because trace moisture in the WTR is quickly evaporated during roasting to form micropores, the effective contact area of the salt-modified WTR powder with sewage is increased when the salt-modified WTR powder is put in, the aperture is widened, the specific surface area is increased, and the beneficial effect of increasing the adsorption efficiency is finally generated. However, the calcination temperature should not exceed 500 ℃, because too high temperature may cause the amorphous state of the metal ions in WTR to be transformed into crystal, so that most of the phosphorus adsorption performance is lost, and too low temperature also causes the phenomena of insufficient void ratio and unobvious optimization of the adsorption performance; in summary, the baking temperature is recommended to be between 350 ℃ and 450 ℃.
The modified WTR aqueous solution absorbs 6mg/L of low-concentration phosphorus (the phosphorus concentration of the domestic sewage is about 4-7mg/L) at the temperature of 25 ℃ at the pH value of about 7, the reaction effect is good, the modified WTR has the phosphorus adsorption rate of more than 70 percent, the adsorption quantity is wholly higher than 3.1mg/g (unmodified WTR), and the residual phosphorus of the solution after 3 hours of reaction meets three indexes, and the effect is good. It is to be noted that Ca contained in WTR2+、Mg2+After being modified by sodium sulfate, a large amount of Na with smaller radius is introduced+Ca with a larger radius2+、Mg2+Since the cation is replaced, Ca and Mg elements in the modified WTR are removed and cannot be detected.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for ultrasonic treatment for 2-4h to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 5-15: 100;
mixing and stirring the modified WTR solution and a sodium alginate solution with the mass fraction of 1-3% uniformly according to the volume ratio of 1: 1-2, then dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 1-3% at the speed of 0.6-1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 0.5-3 mm.
The modified WTR sodium alginate bead has good adsorption performance on phosphorus in sewage, and can be used for efficiently and practically treating domestic sewage of sewage plants in phosphorus-containing sewage with lower concentration, namely below 10mg/L through ligand exchange, chemical precipitation and ion exchangeNow the phosphorus is adsorbed. On the one hand, WTR has been demonstrated to have excellent phosphorus removal effect, and the metal ions contained in the WTR can precipitate with phosphate ions in the sewage, so that the phosphorus removal rate is close to 55%. The salt-modified and heat-roasted WTR enables the introduced Na to be modified by the salt+Ions replace part of cations with larger radius, so that the surface of the WTR becomes rough and loose from an initial compact lamellar structure and a structure with smaller gaps, the lamellar becomes more and thinner, the aperture and the specific surface area are obviously increased, meanwhile, the content of C element in the WTR after salt modification is obviously reduced by thermal roasting, the content proportion of effective adsorption components such as Al, Fe, Si and the like is increased, and certain thin aperture walls on the surface of the WTR can collapse by roasting to form an aperture with larger diameter. Both of the two components contribute to the occurrence of adsorption reaction, and together promote the modified WTR to adsorb and carry more phosphorus elements. The adsorption rate of the modified WTR to phosphorus can reach more than 70 percent, and the modified WTR is embedded and fixed by using gel formed by sodium alginate and sodium sulfate to prepare the micro-gel ball, so that the settleability can be optimized, the modified WT powder is prevented from being blocked and lost, and meanwhile, the micro-bead material has the advantage of being reusable. It is worth to say that the microbeads after adsorbing phosphorus can be desorbed by dilute NaOH solution (0.05-0.1mol/L) to reduce the microbeads back to an unadsorbed state for reuse. In an ideal low-concentration phosphorus-containing solution, after the first three adsorption and desorption processes, the microbeads can still ensure the bead regeneration rate of nearly 80 percent, the bead mass loss is lower than 18 percent, and the microbeads have good reutilization property.
The modified WTR has over 70 percent of phosphorus adsorption rate through salt modification and roasting; the prepared modified WTR sodium alginate bead can be desorbed by NaOH solution and has good reusability; the sewage treatment agent using the modified WTR sodium alginate bead has a phosphorus adsorption rate of more than 95%.
The invention relates to a domestic sewage treatment agent capable of efficiently removing phosphorus. Wherein, the aluminum sulfate and the ferrous sulfate are respectively used as the main components of the aluminum salt dephosphorizing agent and the iron salt dephosphorizing agent, thereby ensuring the dephosphorizing effect. Meanwhile, the chelating reaction of alginic acid to phosphorus is utilized, and the removal effect of total phosphorus in the sewage is enhanced under the condition that the flocculation reaction of aluminum sulfate and sodium carbonate is considered. In addition, the modified WTR sodium alginate bead with excellent dephosphorization effect is added, the phosphorus element can be adsorbed and removed by using ligand exchange, chemical precipitation and ion exchange modes, and the promotion of ion flow in the adsorption process can enhance the original flocculation effect of the flocculant.
Considering that the raw materials can release iron ions and aluminum ions in the sewage in the flocculation process of dephosphorization, the former generates loss on equipment of a sewage treatment plant, and the latter causes huge environmental hidden danger due to discharge. Alginic acid, citric acid that add in the raw materials, these two have the effect of getting rid of heavy metal ion to a certain extent, and the cooperation is used and can be made aluminium ion, the iron ion left over catch through chelation solidification and get rid of from sewage, and the heavy metal that reduces sewage treatment exceeds standard the risk.
The invention fully considers the practical value, optimizes the preparation process and simplifies the raw material configuration. The raw material sodium alginate for preparing the modified WTR sodium alginate bead can be prepared from another raw material alginic acid powder, and the alginic acid powder and the modified WTR sodium alginate bead are mixed, so that the structural stability of the modified WTR sodium alginate bead is maintained, and the storage of the micro-colloid bead is facilitated. In addition, ferrous sulfate in the raw materials is used as a raw material of a coagulant component and also used as a cross-linking agent to participate in coating and fixing of the modified WTR sodium alginate bead and the like.
The sewage treatment agent disclosed by the invention is optimized and screened, and aluminum sulfate and sodium carbonate are taken as flocculating agents, and efficient phosphorus removal is carried out in a flocculation precipitation mode; optimally screening alginic acid serving as a metal chelating agent and citric acid, efficiently removing phosphorus in a chelating and curing mode, and removing residual aluminum salt and iron salt; modified WTR sodium alginate beads prepared by modified WTR (water supply plant residual mud) and sodium alginate are added as a reinforcing material for dephosphorization. On one hand, the modified WTR sodium alginate bead can participate in phosphorus removal in a chemical phosphorus adsorption mode according to the principles of ligand exchange, chemical precipitation and ion exchange, and on the other hand, the modified WTR sodium alginate bead can drive the generation of an ion flow phenomenon due to reaction activation, so that the improvement of the flocculation reaction rate is promoted. More importantly, the modified WTR sodium alginate bead aperture surface is provided with a plurality of chemical adsorption points, stable soluble impurities can be formed at an aperture outlet in the process of adsorbing phosphorus, the aperture is gradually closed, a first barrier is formed, and the sodium alginate gel on the outer surface of the WTR sodium alginate bead enables the steric hindrance to be increased again under the saturation condition of phosphorus adsorption concentration due to the increase of the impurities in the aperture, and the ion migration resistance in the bead is rapidly increased, so that the anti-dissolving capacity of phosphorus in the bead is greatly weakened and the modified WTR sodium alginate bead serves as a second barrier for preventing the phosphorus from being released again. Therefore, compared with the conventional phosphorus removal method, the method has more stable phosphorus removal effect, can not cause the re-release of a large amount of phosphorus under the mechanical treatment means of a treatment plant such as plate-frame filter-pressing effluent and the like, ensures the treatment effect of sewage phosphorus removal, and has good social benefit and economic benefit.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments in the embodiments of the present invention, and it should be understood that the described embodiments are a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
It will be understood that the terms "comprises" and/or "comprising," when used in this specification and the appended claims, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Example 1
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Stirring and reacting in the solution for 6-8 h; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20-30, Na2SO4The concentration of the solution is 0.1-0.5 mol/L; the stirring reaction is specifically operated by firstly slowly stirring for 1-3min and then stirring at the rotating speed of 150-.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Get WTRFiltering the materials;
s3: drying the WTR filtrate at 90-110 deg.C for 10-12 hr, drying, and placing in muffle furnace, tube furnace N2Roasting at 350-450 ℃ for 3-5h under the protection of gas, and cooling to obtain the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for ultrasonic treatment for 2-4h to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 5-15: 100;
mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 1-3% according to the volume ratio of 1: 1-2, uniformly stirring, dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 1-3% at the speed of 0.6-1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 0.5-3 mm.
The domestic sewage treatment agent capable of efficiently removing phosphorus comprises 10-40 parts by weight of the modified WTR sodium alginate bead, 30-90 parts by weight of a flocculating agent, 3-20 parts by weight of a chelating agent, 3-10 parts by weight of ferrous sulfate, 1-3 parts by weight of citric acid and 3-10 parts by weight of reduced iron powder.
Example 2
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Stirring and reacting in the solution for 6-8 h; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20-30, Na2SO4The concentration of the solution is 0.1-0.5 mol/L; the stirring reaction is specifically operated by firstly slowly stirring for 1-3min and then stirring at the rotating speed of 150-.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying the WTR filtrate at 90-110 deg.C for 10-12 hr, drying, and placing in muffle furnace, tube furnace N2Roasting at 350-450 ℃ for 3-5h under the protection of gas, and cooling to obtain the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for ultrasonic treatment for 2-4h to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 5-15: 100;
mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 1-3% according to the volume ratio of 1: 1-2, uniformly stirring, dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 1-3% at the speed of 0.6-1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 0.5-3 mm.
The domestic sewage treatment agent for efficiently removing phosphorus comprises 10-40 parts by weight of the modified WTR sodium alginate bead, 30-90 parts by weight of a flocculating agent, 3-20 parts by weight of alginic acid, 3-10 parts by weight of ferrous sulfate, 1-3 parts by weight of citric acid and 3-10 parts by weight of reduced iron powder; the flocculant comprises 20-50 parts of aluminum sulfate and 10-40 parts of sodium carbonate.
Example 3
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Stirring and reacting for 6 hours in the solution; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20, Na2SO4The concentration of the solution is 0.1 mol/L; the stirring reaction is specifically carried out by slowly stirring for 1min and then stirring at the rotating speed of 150r/min in a water bath environment at the temperature of 30 +/-1 ℃.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying the WTR filtrate in an environment of 90 ℃ for 10 hours, and then drying the WTR filtrate in a muffle furnace and a tube furnace N2Roasting for 3h at 350 ℃ under the protection of gas, and cooling to obtain the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for 2 hours to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 5: 100;
and mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 1% according to the volume ratio of 1: 1, uniformly stirring, dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 1% at the speed of 0.6mm/s for crosslinking and fixing, and finally repeatedly cleaning for 3 times by using ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 0.5-1 mm.
The domestic sewage treatment agent for efficient phosphorus removal comprises 10 parts by weight of the modified WTR sodium alginate bead, 30 parts by weight of a flocculating agent, 3 parts by weight of alginic acid, 3 parts by weight of ferrous sulfate, 1 part by weight of citric acid and 3 parts by weight of reduced iron powder; the flocculating agent comprises 20 parts by weight of aluminum sulfate and 10 parts by weight of sodium carbonate, and the components are uniformly mixed.
Example 4
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Stirring and reacting the mixture in the solution for 8 hours; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 30, Na2SO4The concentration of the solution is 0.5 mol/L; the stirring reaction is specifically carried out by slowly stirring for 3min and then stirring at the rotating speed of 180r/min in a water bath environment at the temperature of 30 +/-2 ℃.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying the WTR filtrate in an environment of 110 ℃ for 12 hours, and then drying the WTR filtrate in a muffle furnace and a tube furnace N2Roasting for 5h at 450 ℃ under the protection of gas, and cooling to obtain the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for ultrasonic treatment for 4 hours to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 15: 100;
and mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 3% according to the volume ratio of 1: 1, uniformly stirring, dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 3% at the speed of 1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 1-3 mm.
The domestic sewage treatment agent for efficiently removing phosphorus comprises 40 parts by weight of the modified WTR sodium alginate bead, 90 parts by weight of a flocculating agent, 20 parts by weight of alginic acid, 10 parts by weight of ferrous sulfate, 3 parts by weight of citric acid and 10 parts by weight of reduced iron powder; the flocculating agent comprises 50 parts by weight of aluminum sulfate and 40 parts by weight of sodium carbonate, and the components are uniformly mixed.
Example 5
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Stirring and reacting in the solution for 7 hours; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 25, Na2SO4The concentration of the solution is 0.2 mol/L; the stirring reaction is specifically carried out by slowly stirring for 2min and then stirring at the rotating speed of 160r/min in a water bath environment at the temperature of 30 ℃.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying the WTR filtrate in an environment at 100 ℃ for 12 hours, and then drying the WTR filtrate in a muffle furnace and a tube furnace N2Roasting for 4h at 400 ℃ under the protection of gas, and cooling to obtain the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
adding the modified WTR into ultrapure water, and placing the ultrapure water under an ultrasonic instrument for 3 hours to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 202100;
and mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 2% according to the volume ratio of 1: 1, uniformly stirring, dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 2% at the speed of 1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 0.5-1.5 mm.
The domestic sewage treatment agent for efficiently removing phosphorus comprises 25 parts by weight of the modified WTR sodium alginate bead, 45 parts by weight of a flocculating agent, 10 parts by weight of alginic acid, 7 parts by weight of ferrous sulfate, 2 parts by weight of citric acid and 7 parts by weight of reduced iron powder; the flocculating agent comprises 25 parts by weight of aluminum sulfate and 20 parts by weight of sodium carbonate.
The following experiments were carried out without further explanation of the technical effects of the present invention.
WTR of the following experiment is a water supply plant iron-containing residual sludge (water treatment residue) provided by a large-scale water supply plant, and the main components of the WTR comprise 25-35% of Si element, 60-70g/kg of Al element, 15-25g/kg of Ca element and 200-250g/kg of Fe element by mass fraction.
The technical scheme of the application is used for preparing the modified WTR, the modified WTR sodium alginate bead and the efficient phosphorus removal domestic sewage treatment agent (hereinafter referred to as sewage treatment agent) of the experimental examples 1-3.
Experimental example 1: taking low-concentration phosphorus-containing domestic sewage as an example, the standard conditions of the component proportion and the treatment effect of the treatment agent are suitable for being used as the production standard of large-scale formal production. Practical factors are considered in an increasing way: such as feeding, uniform particle fineness, recovery of modified WTR sodium alginate microbeads, prevention of machine blockage, and the like.
Experimental example 2: if the treated sewage sludge contains more heavy metal ions, the component weight of the chelating agent and the flocculating agent is properly increased, the proportion of other components is reduced, and the chelating effect is highlighted. Meanwhile, the modified WTR sodium alginate bead is used for one time, and the dephosphorization effect under one time use is maximized. According to economic benefits, the adding amount of the modified WTR sodium alginate microbead component can be reduced properly, so that the phosphorus adsorption saturation of the unit microbead is improved, the phosphorus adsorption rate of the unit microbead is improved, competitive adsorption is avoided, and the full utilization of the unit microbead is met.
Experimental example 3: in the face of the sudden small-range and concentrated phosphorus concentration steep increase phenomenon in the domestic sewage treatment, the preparation is required to be rapid, the reaction is required to be rapid, the time from the experiment to the implementation is shortened, and the treatment effect is required to be rapidly shown. The optimal phosphorus removal effect under the condition of occasional concentrated sewage phosphorus content increase should be considered to increase the number of modified WTR sodium alginate microbeads and cooperate with the increase of other components. The experiments should be branched simultaneously, and necessary data and stage results can be obtained in the shortest time.
The above three experimental examples are described below.
Experimental example 1
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Slowly stirring the solution for 1min, and then stirring the solution for reaction for 8h at the rotating speed of 150r/min in a water bath environment at the temperature of 30 ℃; WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 25, Na2SO4The concentration of the solution was 0.1 mol/L.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying the WTR filter material for 12 hours in an environment of 100 ℃, and roasting in a muffle furnace according to the conditions after drying, wherein the conditions are N in a tube furnace2Roasting for 3h at 400 ℃ under the protection of gas, and taking out the roasted material after the muffle furnace is restored to normal temperature to obtain blocky and soft WTR, namely the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
and weighing 10g of modified WTR, adding the modified WTR into 100mL of ultrapure water, and placing the water under an ultrasonic instrument for 3 hours to obtain a modified WTR solution.
Dissolving 2g sodium alginate powder in 100ml ultrapure water, placing in a water bath kettle, stirring and heating at 60 deg.C, and dissolving completely. And then, mixing the sodium alginate solution and the modified WTR solution, uniformly stirring, then dropping the mixed solution into 100mL of ferrous sulfate solution with the mass fraction of 2% by using a peristaltic pump at the speed of 0.8mm/s, crosslinking and fixing for 24 hours, and finally repeatedly cleaning for 3 times by using ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of about 1 mm. The surface of the modified WTR sodium alginate bead can be covered with a small amount of alginic acid powder for storage.
Preparing a sewage treatment agent:
according to the proportion, 20 parts by weight of aluminum sulfate and 10 parts by weight of sodium carbonate are uniformly mixed to prepare the flocculant. According to the proportion, 40 parts by weight of modified WTR sodium alginate bead, 30 parts by weight of flocculant, 10 parts by weight of ferrous sulfate, 3 parts by weight of citric acid, 10 parts by weight of reduced iron powder and 5 parts by weight of alginic acid are uniformly mixed.
To meet and accommodate the additional requirements of mass production: except that the modified WTR sodium alginate bead is about 1mm, the particle fineness of other raw materials is unified, and the method is suitable for putting and stirring in a factory. The minimum diameter of the modified WTR sodium alginate bead controlled to be about 1mm is to prevent overlarge rubber beads from blocking pipeline equipment during throwing, and simultaneously, the recyclability of the rubber beads during throwing during standard low-concentration phosphorus-containing domestic sewage treatment is considered as far as possible, so that the rubber beads are repeatedly utilized. The particle fineness of other raw materials is different, and the raw materials must be ground and crushed, and the uniform particle fineness is about 100 meshes. The aim is to expand the reaction contact area of the powder and sewage in the stirring process of the powder and the sewage in the triple reactor, so that the reaction is thorough, the medicament and the phosphorus-containing sewage can fully react, the phenomena of powder agglomeration and coating are prevented, and the phosphorus removal effect is poor. However, too low particle fineness can cause serious dust flying phenomenon of the medicinal powder, equipment blockage and working environment reduction, and harm to the health of staff. Specifically, various other raw material powders are input into a coarse powder grinding machine through different feeding pipelines for crushing and screening, and then a finished product is obtained through one-time final mixing.
Because aluminum sulfate in the rest raw materials is strong acid and weak base salt and is weakly acidic, and sodium carbonate belongs to strong base and weak acid salt and is weakly alkaline, in order to prevent the powder reaction caused by the conditions of mechanical combination, temperature rise during grinding and the like, different feeding pipelines and different crushers are arranged for particle refinement. Besides, other raw materials such as alginic acid and citric acid should be fed in different routes according to their pH values.
The sewage treatment agent of the experimental example is suitable for treating general domestic sewage.
Experimental example 2
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Slowly stirring the solution for 1min, and then stirring the solution for reaction for 8h at the rotating speed of 160r/min in a water bath environment at the temperature of 30 ℃; WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20, Na2SO4The concentration of the solution was 0.1 mol/L.
S2: after the stirring reaction is finished, centrifugally filtering, washing with ultrapure water to remove residuesNa of (2)2SO4Obtaining WTR filter;
s3: drying the WTR filter material for 12 hours in an environment of 100 ℃, and roasting in a muffle furnace according to the conditions after drying, wherein the conditions are N in a tube furnace2Roasting for 5h at 450 ℃ under the protection of gas, and taking out the roasted material after the muffle furnace is restored to normal temperature to obtain blocky and soft WTR, namely the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
and weighing 10g of modified WTR, adding the modified WTR into 100mL of ultrapure water, and placing the water under an ultrasonic instrument for 3 hours to obtain a modified WTR solution.
Dissolving 2g sodium alginate powder in 100ml ultrapure water, placing in a water bath kettle, stirring and heating at 60 deg.C, and dissolving completely. And then, mixing the sodium alginate solution and the modified WTR solution, uniformly stirring, then dropping the mixed solution into a ferrous sulfate solution with the mass fraction of 2% through a peristaltic pump at the speed of 0.8mm/s for crosslinking and fixing for 24 hours, and finally repeatedly cleaning with ultrapure water for 3 times to obtain the modified WTR sodium alginate bead with the diameter of 2-3 mm.
Preparing a sewage treatment agent:
according to the proportion, 30 parts by weight of aluminum sulfate and 30 parts by weight of sodium carbonate are taken and evenly mixed to prepare the flocculant. According to the proportion, 40 parts by weight of modified WTR sodium alginate bead, 60 parts by weight of flocculant, 10 parts by weight of ferrous sulfate, 8 parts by weight of citric acid, 5 parts by weight of reduced iron powder and 5 parts by weight of alginic acid are uniformly mixed.
The sewage treatment agent of the experimental example is suitable for treating sewage with excessive heavy metals and overhigh pH value in an alkaline environment. Under the condition that the microbeads are easily polluted by complex sewage or when no recovery condition or recovery equipment exists, the recoverability of the microbeads is abandoned, the one-time effect of the microbeads is considered to be maximized, and the effect of the microbeads is enhanced by sacrificing the recoverability, so that the microbeads have certain capacity of containing metal ions.
In order to meet the requirements of large-scale production: under the conditions that the heavy metal content is slightly high and the pH value is alkaline, the adsorption effect of the modified WTR sodium alginate bead on phosphorus may be reduced to a certain degree, and meanwhile, the conditions that the regeneration rate of the formed ball is reduced and the quality loss of the formed ball exceeds a certain limit in the process of desorbing and reducing the phosphorus removal performance of the bead by using a dilute NaOH solution when the modified WTR sodium alginate bead is recycled after adsorbing phosphorus due to complex sewage components need to be considered, namely, the condition that the benefit of the repeated use of the bead is reduced, at this time, the disposable use effect of the WTR sodium alginate bead should be focused. (note: regeneration rate of balling and loss of quality of balling are indexes reflecting reusability, the modified sodium alginate bead can be recovered after adsorbing phosphorus, namely desorbing through NaOH dilute solution, and returning the micro bead to the state of not adsorbing phosphorus.)
In consideration of the economic cost in use, the longer the muffle furnace firing time, and the increased firing temperature contribute to the generation of more pore sizes, making the structure porous coral-like. At the expense of the regeneration rate of the beads and the increase of the mass loss during repeated use, the phosphorus removal effect of one-time use is required to be maximally presented.
The modified WTR powder particles prepared according to this example were controlled by raw material ratios and a calcination process, and had larger particles and more voids and pores than the modified WTR sodium alginate beads of experimental example 1. In the process of adsorbing phosphorus, the redundant pore diameter can also contain a certain amount of metal ions in the sewage, and the metal ions are coordinated with the chelating agent to remove heavy metals in the sewage. In consideration of economic cost in use, the addition amount of the modified WTR sodium alginate bead in each 100g of sewage treatment agent is reduced from 10 to 5.
Experimental example 3
The preparation method of the modified WTR comprises the following steps:
s1: adding WTR to Na2SO4Slowly stirring the solution for 1min, and then stirring the solution for reaction for 6h at the rotating speed of 150r/min in a water bath environment at the temperature of 30 ℃; WTR and Na2S04The solid-liquid mass ratio of the solution is 1: 25, Na2SO4The concentration of the solution was 0.1 mol/L.
S2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: cyclizing the WTR filter at 105 ℃Drying for 10 hours, and roasting in a muffle furnace according to the conditions of N in a tube furnace2Roasting for 3h at 400 ℃ under the protection of gas, and taking out the roasted material after the muffle furnace is restored to normal temperature to obtain blocky and soft WTR, namely the modified WTR.
The preparation method of the modified WTR sodium alginate bead comprises the following steps,
and weighing 10g of modified WTR, adding the modified WTR into 100mL of ultrapure water, and placing the water under an ultrasonic instrument for 3 hours to obtain a modified WTR solution.
Dissolving 2g sodium alginate powder in 100ml ultrapure water, placing in a water bath kettle, stirring and heating at 60 deg.C, and dissolving completely. And then, mixing the sodium alginate solution and the modified WTR solution, uniformly stirring, then dropping the mixed solution into 100mL of ferrous sulfate solution with the mass fraction of 2% by using a peristaltic pump at the speed of 0.8mm/s, crosslinking and fixing for 24 hours, and finally repeatedly cleaning for 3 times by using ultrapure water to obtain the modified WTR sodium alginate bead with the diameter of 1-2 mm. The surface of the modified WTR sodium alginate bead can be covered with a small amount of alginic acid powder for storage.
Preparing a sewage treatment agent:
according to the proportion, 40 parts by weight of aluminum sulfate and 45 parts by weight of sodium carbonate are uniformly mixed to prepare the flocculant. According to the proportion, 40 parts by weight of modified WTR sodium alginate bead, 85 parts by weight of flocculant, 10 parts by weight of ferrous sulfate, 10 parts by weight of citric acid, 10 parts by weight of reduced iron powder and 10 parts by weight of alginic acid are uniformly mixed.
The sewage treatment agent of the experimental example is suitable for sewage treatment with sudden concentration increase of phosphorus-containing sewage and rapid reaction requirement; if necessary, the modified WTR sodium alginate bead component is further added, and the rest components are added, for example, about 20 modified WTR sodium alginate beads are added into each 100g of treating agent powder, and the mixture is uniformly mixed.
Firstly, verifying the influence of roasting temperature on the phosphorus removal effect of the modified WTR
The modified WTR of the control experiments 1-1 and 1-2 is prepared by adopting the preparation method of the modified WTR of the experiment 1, wherein the experiment 1-1 adopts the roasting at 300 ℃, the experiment 1-2 adopts the roasting at 500 ℃, and other processes are the same as the preparation method of the experiment 1.
The preparation method of experiment 2 modified WTR is adopted to prepare modified WTR of comparison experiments 2-1 and 2-2, wherein experiment 2-1 adopts 300 ℃ roasting, experiment 2-2 adopts 500 ℃ roasting, and other processes are the same as the preparation method of experiment 2.
Modified WTRs prepared by WTR, experiment 1, experiment 2, experiment 1-1, experiment 1-2, experiment 2-1 and experiment 2-2 are used for treating low-concentration phosphorus domestic sewage of 6mg/L at the temperature of 25 ℃, the phosphorus concentration after treatment of each group is measured, and the phosphorus adsorption rate is calculated, wherein the results are shown in the following table 1.
TABLE 1
The results show that the modified WTR treated by the method has higher phosphorus adsorption rate than the untreated WTR; in addition, in the preparation process of the modified WTR, the roasting temperature has obvious influence on the phosphorus adsorption rate of the modified WTR.
Second, modified WTR sodium alginate bead recycling experiment
Modified WTR sodium alginate beads prepared in experimental examples 1 and 2 were adsorbed in an ideal low-concentration phosphorus-containing solution (1L, 6mg/L) three times, and after each adsorption, the beads were desorbed using 0.1mol/L NaOH solution, and the mass of each desorbed modified WTR sodium alginate bead was measured, and the bead formation regeneration rate and bead formation mass loss were calculated, and the results are shown in table 2.
TABLE 2
The data show that in ideal low-concentration phosphorus-containing solution, after three times of adsorption and desorption, the sodium alginate bead can still ensure the bead regeneration rate of nearly 80 percent, and the bead mass loss is lower than 18 percent, which indicates that the modified WTR sodium alginate bead has good reutilization property.
Third, verification of dephosphorization effect of sewage treatment agent
1. Effect of removing phosphorus from excess sludge obtained after domestic sewage treatment
Taking residual sludge produced by domestic sewage in a sewage plant A as a sample, and dividing the sample into three parts; the sewage treatment agents prepared in experimental examples 1 to 3 (the sewage treatment agent and the sludge were mixed in a mass ratio of 1: 2500) were used for phosphorus removal treatment, and the phosphorus content before and after the treatment was measured, and the results are shown in table 3 below.
TABLE 3
As can be seen from the above table, the domestic sewage treatment agent for efficiently removing phosphorus can further remove phosphorus from residual sludge after treatment in a sewage plant, and the total phosphorus of a sludge sample obtained after treatment is obviously reduced compared with that of original sludge.
Taking residual sludge produced by domestic sewage in a sewage plant B as a sample, precipitating, and taking supernatant of the original sludge to divide into three parts; the sewage treatment agents prepared in experimental examples 1 to 3 (the sewage treatment agent and the supernatant of the raw sludge were mixed in a mass ratio of 1: 2500) were used for phosphorus removal treatment, and the phosphorus content before and after the treatment was measured, and the results are shown in table 4 below.
TABLE 4
Taking residual sludge produced by domestic sewage in a sewage plant C as a sample, and dividing the sample into two parts; the sewage treatment agents prepared in experimental examples 1 and 3 (the sewage treatment agent and the sludge were mixed in a mass ratio of 1: 2500) were used for phosphorus removal treatment, and the phosphorus content before and after the treatment was measured, and the results are shown in table 5 below.
TABLE 5
Therefore, the sewage treatment agent provided by the invention has a good effect on treatment of excess sludge generated by domestic sewage with different physicochemical characteristics (namely different sewage plants).
2. Verification of dephosphorization effect of sewage treatment agent
In order to show the correlation between the formula components of the sewage treatment agent and the dephosphorization effect, the sewage treatment agent in experimental example 3 is used for carrying out dephosphorization effect analysis on specific data of the sludge in the secondary sedimentation tank of the sewage plant D. The measured data included total phosphorus content in the stock solution supernatant, the post-reaction supernatant, the feed effluent, and the press effluent (the stock solution supernatant and the post-reaction supernatant were obtained from the triple reactor in the wastewater treatment process before and after the reaction, and the feed effluent and the press effluent were obtained from the plate frame in the wastewater treatment process before and after the filter pressing), and the results are shown in table 6.
TABLE 6
It can be seen that in the sewage treatment process, the treating agent has better sewage dephosphorization effect after reaction to plate-frame filter pressing. For the squeezed effluent, a trace amount of sewage treatment agent can be added to carry out dephosphorization retreatment on the squeezed effluent, so that the phosphorus index of the water quality further reaches two types of water and above.
The sewage treatment agent components of experimental example 3 were re-optimized (the sewage treatment agents of experimental example 3 and experimental example 2 were mixed and used in a mass ratio of 1: 3, and the phosphorus removal effect shown in table 7 was obtained.
TABLE 7
The results in tables 6 and 7 show that the total phosphorus content of the supernatant after the reaction can be lower than 0.43mg/L through the sewage treatment process, the sewage treatment agent has experimental repeatability, and the total phosphorus concentration of the fed water and the discharged water can be further reduced to 0.86mg/L from 1.65mg/L after the components of the sewage treatment agent are optimized.
Furthermore, the modified WTR sodium alginate bead in the sewage treatment agent in the experimental example 3 is subjected to adsorption and desorption for three times in the sewage treatment process, the balling regeneration rate can still reach 71.1 percent, the balling mass loss can be as low as 17.6 percent, and the possibility of repeated recovery is met. The added configuration in the sewage treatment plant has lower cost and operability on the WTR sodium alginate bead recycling equipment.
3. Verification of application effect of sewage treatment agent
To fully illustrate the practical value of the domestic sewage treatment agent, the detailed data of sewage treatment in a certain sewage plant (E sewage plant) in Liaoning province is comprehensively analyzed. In the practical application of primary sewage dephosphorization, the treatment agent provided by the invention is used for sequentially completing the screening of the sewage treatment agent with the optimal proportion, the regulation and control of the adding amount, and the simulation test of sewage purification by placing the treatment agent in the whole sewage treatment process, so that the advantages of the treatment agent are fully utilized, and the value creation is formed.
The raw sludge of 200g of the sewage plant E was taken and added with water to dissolve in 500mL beakers, and 200ppm of the sewage treatment agent of the experimental examples 1-3 was added to measure the dephosphorization effect in three groups, and the results are shown in Table 8.
TABLE 8
| E samples from sewage plants | pH | TP (Total phosphorus) mg/L |
| Raw mud | 7.1 | 1.14 |
| Experimental example 1 | 7.4 | 0.13 |
| Experimental example 2 | 7.5 | 0.08 |
| Experimental example 3 | 7.6 | 0.17 |
As can be seen from the above table, the sewage treatment agent of Experimental example 2 has the best dephosphorization effect on the sewage of the sewage plant E.
And (4) dividing into four groups, respectively taking 200g of raw sludge of the E sewage plant, adding water into 500mL of beakers, respectively adding different amounts of the sewage treatment agents in the experimental example 2 shown in the table 9, and measuring the dephosphorization effect, wherein the results are shown in the table 9.
TABLE 9
| E samples from sewage plants | pH | TP (Total phosphorus) mg/L |
| Raw water | 7.2 | 1.31 |
| Amount of addition200ppm | 7.3 | 0.07 |
| The dosage is 150ppm | 7.2 | 0.09 |
| The dosage is 100ppm | 7.2 | 0.12 |
| The dosage is 50ppm | 7.2 | 0.13 |
As can be seen from the table, the sewage treatment agent added with 200ppm of the sewage treatment agent in the experimental example 2 has the best dephosphorization effect on the sewage of the sewage plant E.
With tables 8 and 9 as data bases, the sewage treatment agent of experimental example 2 was put into a sewage plant E to perform a sewage purification test in an actual productive sewage treatment process, and the phosphorus removal effect was continuously recorded for four days, with the results shown in table 10.
Watch 10
Note: the feeding water outlet refers to water entering the plate frame mud press, and the squeezing water outlet refers to water outlet after being squeezed by the plate frame mud press.
It can be indirectly seen from table 10 that although the optimal proportion of the sewage treatment agent is obtained by the preliminary test, the actual treatment simulation test of the sewage is required to realize the controllability assurance of the actual application of the treatment agent, and finally the domestic sewage treatment agent of the present invention is made to form the actual value creation.
Although the present invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims. The techniques, shapes, and configurations not described in detail in the present invention are known techniques.
Claims (10)
1. A preparation method of a modified WTR is characterized by comprising the following steps:
s1: adding WTR to Na2SO4Stirring and reacting in the solution for 6-8 h; the WTR and Na2SO4The solid-liquid mass ratio of the solution is 1: 20-30, Na2SO4The concentration of the solution is 0.1-0.5 mol/L;
s2: after the stirring reaction was completed, the reaction mixture was centrifuged, and washed with ultrapure water to remove the remaining Na2SO4Obtaining WTR filter;
s3: drying WTR filter material at 90-110 deg.C, drying and adding N2Roasting for 3-5h under the environment of 350-450 ℃ under the protection of gas, and cooling to obtain the modified WTR.
2. The preparation method of a modified WTR as claimed in claim 1, wherein the stirring reaction in step S1 is performed by stirring slowly for 1-3min and then stirring at a rotation speed of 150-180r/min in a water bath environment at 30 ± 3 ℃.
3. The method for preparing a modified WTR according to claim 2, wherein the drying time in step S3 is 10-12 hours.
4. The method for preparing a modified WTR according to claim 3, wherein the modified WTR is prepared by a process comprisingIn the step S3, N is introduced into a muffle furnace, a tube furnace2Roasting for 3-5h at the temperature of 350-450 ℃ under the protection of gas.
5. The method for preparing modified WTR according to claim 1, wherein the WTR is a water treatment residue, and the composition comprises 25-35% by mass of Si, 60-70g/kg of Al, 15-25g/kg of Ca and 200-250g/kg of Fe.
6. A modified WTR prepared by the preparation method according to any one of claims 1 to 5.
7. A preparation method of a modified WTR sodium alginate bead is characterized by comprising the following steps,
adding the modified WTR of claim 6 into ultrapure water, and placing under an ultrasonic instrument for 2-4h to obtain a modified WTR solution; the mass ratio of the modified WTR to the ultrapure water is 5-15: 100;
uniformly mixing the modified WTR solution with a sodium alginate solution with the mass fraction of 1-3% according to the volume ratio of 1: 1-2, then dripping the mixed solution into a ferrous sulfate solution with the mass fraction of 1-3% at the speed of 0.6-1.0mm/s for crosslinking and fixing, and finally cleaning with ultrapure water to obtain the modified WTR sodium alginate bead.
8. A domestic sewage treatment agent for efficient phosphorus removal, which is characterized by comprising 10-40 parts by weight of the modified WTR sodium alginate bead of claim 7, 30-90 parts by weight of a flocculating agent, 3-20 parts by weight of a chelating agent, 3-10 parts by weight of ferrous sulfate, 1-3 parts by weight of citric acid and 3-10 parts by weight of reduced iron powder.
9. The domestic sewage treatment agent for efficient phosphorus removal of claim 8, wherein the flocculant comprises 20-50 parts by weight of aluminum sulfate and 10-40 parts by weight of sodium carbonate.
10. The efficient phosphorus removal domestic sewage treatment agent of claim 8, wherein the chelating agent is alginic acid.
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| JPS5531409A (en) * | 1978-08-25 | 1980-03-05 | Asahi Chem Ind Co Ltd | Removing phosphate ion from waste water |
| JP2014155902A (en) * | 2013-02-15 | 2014-08-28 | Sanai Fujita | Method and plant for treating incineration ash of garbage and sewage sludge |
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