阅读说明：本技术 一种利用过氧化钙进行污泥脱水调理的方法 (Method for dewatering and conditioning sludge by using calcium peroxide ) 是由 武博然 戴晓虎 柴晓利 汪浩 丁可 周政 汪秀仲 于 2020-04-27 设计创作，主要内容包括：本发明公开一种利用过氧化钙进行污泥脱水调理的技术方法：用盐酸调节污泥初始pH值至酸性范围,在恒速搅拌条件下,先投加均相催化剂硫酸亚铁,混合搅拌均匀后,再投加过氧化钙,充分反应后测定污泥毛细吸水时间和比阻的变化情况。采用3mol/L盐酸调节污泥初始pH值至2～6,在恒速搅拌条件下,先投加0.125～1.25mmol/g污泥干基质量的均相催化剂硫酸亚铁,混合搅拌均匀后,再投加0.025～0.15g/g污泥干基质量的过氧化钙,充分反应后即可实现污泥脱水性能的有效提升。(The invention discloses a technical method for dewatering and conditioning sludge by using calcium peroxide, which comprises the following steps: adjusting the initial pH value of the sludge to be in an acidic range by hydrochloric acid, firstly adding a homogeneous catalyst ferrous sulfate under the condition of constant-speed stirring, uniformly mixing and stirring, then adding calcium peroxide, and measuring the capillary water absorption time and the specific resistance change condition of the sludge after full reaction. Adjusting the initial pH value of the sludge to 2-6 by using 3mol/L hydrochloric acid, firstly adding 0.125-1.25 mmol/g of homogeneous catalyst ferrous sulfate in dry basis weight of the sludge under the condition of constant-speed stirring, uniformly mixing and stirring, then adding 0.025-0.15 g/g of calcium peroxide in dry basis weight of the sludge, and after full reaction, effectively improving the sludge dewatering performance.)

1. A method for treating sludge by using calcium peroxide is characterized by comprising the following steps: the method comprises the following steps: adjusting the initial pH value of the sludge to be in an acidic range by adopting hydrochloric acid, firstly adding a homogeneous catalyst ferrous sulfate under the condition of constant-speed stirring, uniformly mixing and stirring, then adding calcium peroxide, and measuring the capillary water absorption time and the specific resistance change condition of the sludge after full reaction.

2. The method for treating sludge using calcium peroxide according to claim 1, wherein: the water content of the sludge is more than or equal to 95 percent.

3. The method for treating sludge using calcium peroxide according to claim 1, wherein: the concentration of the hydrochloric acid for adjusting the initial pH value of the sludge is 1-3 mol/L.

4. The method for treating sludge using calcium peroxide according to claim 1, wherein: and adjusting the pH value of the sludge to be 2-6 by using hydrochloric acid.

5. The method for treating sludge using calcium peroxide according to claim 1, wherein: the adding amount of the ferrous sulfate is 0.125-1.25 mmol/g of the dry mass of the sludge.

6. The method for treating sludge using calcium peroxide according to claim 1, wherein: the adding amount of the calcium peroxide is 0.025-0.15 g/g of the dry mass of the sludge.

Technical Field

The invention belongs to the technical field of environmental protection, and relates to a method for dewatering and conditioning sludge by using calcium peroxide.

Background

Sludge is a necessary byproduct of biological sewage treatment, contains a large amount of pathogenic bacteria, heavy metals and toxic organic matters, and can become a source of environmental pollution if not properly treated. With the rapid development of economic construction and urbanization level in China, the sludge production amount is increasing day by day. The dehydration can effectively realize the volume reduction of the sludge, reduce the fluidity and improve the incineration heat value, so the method is the primary step of sludge treatment, however, the sludge presents colloidal floc, the high hydrophilicity and the extremely poor dehydration performance are realized, the technical means such as coagulation, flocculation, ultrasonic treatment, microwave radiation, freeze thawing, electrolysis and the like are proved to effectively improve the dehydration performance of the sludge, but the problems of too high dosage of a medicament, large sludge capacity-increasing ratio, harsh reaction conditions and the like limit the wide application of the technical means.

Advanced oxidation can destroy the stable floc structure of the sludge, and avoid the adverse effect of colloidal floc on the sludge dewatering performance. Fenton, fenton-like and ozone are the most common advanced oxidation reagents, but the liquid or gaseous advanced oxidation reagents are inconvenient to transport, and excessive amounts of ozone and hydrogen peroxide may capture hydroxyl radicals, reducing the generation efficiency of oxidative radicals, and meanwhile, hydrogen peroxide has poor stability in a complex organic system, can be decomposed into water and oxygen, and limits the effective generation of the hydroxyl radicals. The calcium peroxide is a safe multipurpose inorganic peroxide, can be gradually dissolved and slowly released in a water phase, is used for dewatering and conditioning the sludge, avoids the problem that the stability of the hydrogen peroxide with high concentration and concentrated feeding in a complicated sludge organic system is poor, and can also be used for neutralizing negative charges on the surface of the sludge by utilizing dissolved calcium ions to realize the coagulation of sludge particles, discharge water among the particles and improve the dewatering performance.

The invention provides a technical method for sludge dehydration conditioning by using calcium peroxide, which forms continuous and stable hydroxyl radical oxidation capability in a sludge complex organic system by using a hydrogen peroxide slow release effect in a solid calcium peroxide dissolving process, effectively strengthens coagulation reaction on sludge solid particles by using affinity performance of calcium ions and sludge extracellular polymers, synchronously improves sludge dehydration performance by virtue of two functions of oxidation and coagulation, and provides a new technical selection way for efficient sludge dehydration conditioning.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a solid advanced oxidation reagent, namely calcium peroxide, which can effectively improve the sludge dewatering performance.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

the method for sludge dehydration conditioning by using calcium peroxide comprises the following steps: hydrochloric acid is adopted to adjust the initial pH value of the sludge to be in an acidic range, and a homogeneous catalyst ferrous sulfate (FeSO) is added firstly under the condition of constant-speed stirring₄) And after mixing and stirring uniformly, adding calcium peroxide. As shown in equation (1), an acidic pH favors CaO₂Generation of H by dissolution of₂O₂，H₂O₂In Fe²⁺OH (see a reaction formula of 2-5) is generated under catalysis, and the dehydration performance is improved by oxidizing and cracking the OH and mineralizing organic matters in the sludge. And after the reaction of the conditioner and the sludge is fully completed, measuring the capillary water absorption time and the specific resistance change condition of the sludge.

CaO₂+2H⁺＝Ca²⁺+H₂O₂(1)

H₂O₂+Fe²⁺＝·OH+OH^-+Fe³⁺(2)

Fe³⁺+H₂O₂＝Fe²⁺+HO₂·+H⁺(3)

HO₂·＝O₂·^-+H⁺(pKa＝4.8)(4)

O₂·^-+Fe³⁺＝Fe²⁺+O₂(5)

Further, the water content of the sludge is more than or equal to 95%.

Preferably, the concentration of the hydrochloric acid for adjusting the initial pH value of the sludge is 1-3 mol/L.

Preferably, the pH value of the sludge after being adjusted by the hydrochloric acid is 2-6.

Preferably, the dosage of the ferrous sulfate is 0.125-1.25 mmol/g of dry mass of the sludge.

Preferably, the addition amount of the calcium peroxide is 0.025-0.15 g/g of dry mass of the sludge.

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

the raw materials selected by the sludge dewatering conditioning technical method disclosed by the invention are easy to obtain, the adding amount is low, the reaction condition is mild, the sludge extracellular polymeric substances can be cracked through the free radical oxidation reaction, the water holding performance of extracellular polymeric substance aggregates is damaged, the density difference of sludge solid and liquid can be effectively increased through the flocculation effect of calcium ions, the effective discharge of difficult-to-remove water such as sludge interstitial water is promoted, the sludge dewatering performance is enhanced, and the sludge dewatering conditioning technical method has a wide market application prospect.

Detailed Description

The present invention will be described in further detail with reference to examples.