CN1907885A

CN1907885A - Oyster case active filtering material for sewage treatment and preparation method thereof

Info

Publication number: CN1907885A
Application number: CNA2005100469829A
Authority: CN
Inventors: 马守祥
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-08-02
Filing date: 2005-08-02
Publication date: 2007-02-07
Anticipated expiration: 2025-08-02
Also published as: CN100441522C

Abstract

The invention discloses a oyster shell filter with biological activity for wastewater treatment and its manufacturing method, relating to a special biological filter in wastewater treatment field. It is characterized by using natural oyster shell as the main raw material, preparing the activated biological filter with light weight, multi-pore, large specific surface area and strong microbial compatibility through inspection, heating, and pore forming by acidification. The main indicators of quality of oyster shell filter with biological activity are bulk density of 0.4 t/m3, voidage of 90%, porosity of 20-30, specific surface area of 1.8 * 104 m2/kg, and average pore size of 80 mum. The invention has the advantages of a wide variety of sources for raw materials (scrap oyster shell garbage), simple production process, low cost, and no secondary pollution.

Description

Oyster shell active biological filter material for sewage treatment and preparation method thereof

Technical Field

The invention belongs to the technical field of sewage treatment, and particularly relates to an active biological filter material which is prepared by taking natural oyster shells as a main raw material and carrying out acidification and pore-forming on the raw material, and has light weight, multiple micropores and large specific surface area, and a preparation method thereof.

Background

At present, a plurality of treatment methods are used for treating industrial wastewater and urban domestic sewage, such as a chemical oxidation-reduction method, a chemical precipitation method, a membrane separation method, a biochemical method, an activated sludge method and a biofilm method. The aeration biofilter which is the representative process of the biofilm process is the most widely applied and has the development prospect at present; one of the keys for determining the performance of the biological aerated filter is the performance of the filter material, and the ideal filter material has the following characteristics: can provide a large amount of surface area for microorganism attachment; making the sewage flow through the biological membrane in a liquid membrane state; enough void ratio ensures ventilation and oxygen supply, and the dropped biological membrane can flow out of the filter tank along with water; is not decomposed by microorganisms and does not inhibit the growth of microorganisms; has certain mechanical strength and low cost.

The filter materials used by the existing biological aerated filter mainly comprise two main types of natural pebbles and ceramic granules; although the natural pebbles which meet the particle grading basically meet the requirements, the defects are that the stacking density is large, the void ratio is small, the specific surface area is small, the application is limited, and various synthetic sintered ceramsite have the main properties which are better than those of pebbles, but have the defects of poor mechanical strength, short service life, easy fading and damage after long-term use, high price and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing an oyster shell active biological filter material for sewage treatment and a manufacturing method thereof aiming at the defects of natural pebble filter materials and various synthetic sintered ceramsite filter materials.

The technical scheme adopted by the invention for solving the problems is as follows: by using the excellent physical characteristics of small bulk density, natural warpage, multiple micropores, high porosity and the like and the characteristics of good chemical processability of oyster shells which are massively discarded in coastal areas as raw materials and by using an acid-washing pore-forming process, the number of micropores on the surface of the oyster shells is increased, and the special filter material for high-quality sewage, which is small in bulk density, high in porosity, multiple micropores and strong in microbial affinity, is prepared; the main chemical components of the oyster shell are biological calcium, the oyster shell is placed in aqueous solution containing sulfuric acid, calcium carbonate on the surface of the oyster shell and the sulfuric acid are subjected to chemical reaction to generate calcium sulfate and calcium sulfite, water and carbon dioxide are generated, carbon dioxide gas escapes, and after the calcium sulfate and the calcium sulfite attached to the surface of the oyster shell are washed away by water, more micropores are formed on the surface of the oyster shell, and the chemical equation is as follows: ，。

the production process of the invention comprises the following steps: sorting and cleaning → heating and drying → acidification and pore forming → washing and drying.

Sorting and washing: and sorting the collected oyster shells. The requirements of sorting appearance quality are that the thickness of the shell is more than or equal to 2mm, the length is more than or equal to 50mm, and the width is more than or equal to 30 mm; the quality requirements of the chemical components are as follows: 39-41% of calcium, 26-28% of iron, 12-12.8% of manganese, 7.9-8.4% of zinc, 6-7% of strontium, 2.3-2.5% of nickel and less than 2.3% of copper. And cleaning the qualified products after sorting, drying in the shade, and entering the next procedure.

Heating and drying: and (3) putting the oyster shells dried in the shade into a heating chamber, heating and drying, raising the temperature from the normal temperature to 180 ℃ for 50 minutes, and then keeping at the constant temperature of 180 ℃ for 10 minutes.

Acidifying and pore-forming: directly loading the oyster shells subjected to heating and drying treatment into an acidification pore-forming device for soaking and washing, and carrying out acidification pore-forming. The concrete requirements are as follows: the soaking time is 72h, the water quality of the device requires that waste sulfuric acid solution or power plant desulfurization wastewater (the pH value of the water quality is 2-5) is contained, water enters from the bottom of the device and flows upwards through the soaked and washed oyster shells, and the water flow speed is 1-2 m/h. The water is recycled into the device for reuse after flowing out.

Washing and drying: and washing the acidified and pore-formed product with water, placing the product in a ventilation shed for drying, weighing and boxing.

The invention has the beneficial effects that:

1. the product has small bulk density of only 0.4t/m³The porosity is high and can reach 90%, the surface micropores can reach 40-60%, and the filter material has high microbial affinity, so that the filter material is a high-quality special sewage engineering filter material with good anti-blocking performance, good hydraulic conditions and high biochemical reaction efficiency. Because of its high treatment efficiency and small stacking density, it can save a lot ofcapital construction land and capital construction cost.

2. The oyster shells discarded in aquaculture in coastal areas are used as raw materials, so that the production cost is reduced, the pollution of a large amount of oyster shells discarded by seasides to the environment is solved, the harm is turned into the benefit, and the waste is changed into the valuable.

3. The desulfurization acid waste water of the power plant is used as the production water for acidizing and pore-forming, so that the production cost can be reduced, and the treatment cost of the desulfurization waste water of the power plant can be reduced.

Detailed Description

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

The active biological filter material is prepared by taking natural oyster shell waste as a product raw material and performing sorting, cleaning, heating, drying, acidification, pore forming, washing and drying processes.

1. The collected oyster shells are sorted and cleaned, the shape length is more than or equal to 50mm, the width is more than or equal to 30mm, the shell thickness is more than or equal to 2mm, the chemical components of the oyster shells which are tested in batches are calcium content 40%, iron content 27%, manganese content 12%, zinc content 8%, strontium content 6%, nickel content 2.3% and copper content 2.2%, and the oyster shells are washed clean and dried in the shade for later use.

2. And (3) putting the sorted raw materials into a drying chamber for heating treatment, wherein the heating time is divided into a heating-up heating section and a constant-temperature heating section, the heating-up heating section is used for heating from normal temperature to 180 ℃ within 50 minutes, and the constant-temperature heating section is used for heating at 180 ℃ for 10 minutes.

3. Putting the oyster shell after heating treatment into an acidification pore-forming device, (the production water can adopt a sulfuric acid aqueous solution with a pH value of 2-4, and can also adopt desulfurization waste water of a power plant), (the) aqueous solution continuously flows upwards from the bottom in the device, when flowing through the oyster shell, chemical reaction can be carried out, some calcium on the surface of the aqueous solution is replaced, calcium sulfate, calcium sulfite, water and carbon dioxide are generated, the oyster shell is continuously washed by the continuously upwards flowing water flow, the reaction and washing are continuously carried out, a plurality of micropores are slowly formed on the surface of the oyster shell, the pH value of the production water is 2-4, the rising speed of the water is 2m/h, the oyster shell stays in a pool, and the reaction time is 72 hours.

4. Oyster shell after the pore-forming is taken out from the device and is washed clean with water, and after being dried in the shade in the ventilation shed, the high-quality active biological filter material with light weight, microporous surface and small stacking density can be prepared, and the product quality indexes are as follows:

① bulk density 0.4t/m³

② bulk porosity: 90%

③ specific surface area 1.8X 10⁴m²/kg

④ average pore diameter of 80 μm

⑤ surface porosity of 40-60%

Claims

1. An active biological filter material for sewage treatment and a manufacturing method thereof are characterized in that: the method takes oyster shells which are wastes of coastal region cultivation as raw materials, and prepares the active biological filter material with light weight, multiple micropores and large specific surface area through the processes of sorting, heating, acidification, pore-forming and the like.

2. The active biological filter material for sewage treatment and the manufacturing method thereof according to claim 1, wherein: the heating and drying process is to heat the mixture from normal temperature to 180 ℃ for 50 minutes and then heat the mixture for 10 minutes at the constant temperature of 180 ℃.

3. The active biological filter material for sewage treatment and the manufacturing method thereof according to claim 1, wherein: acidification pore-forming device adopts the bottom to intake and upwards flows through waiting to make a hole oyster shell, goes out water recirculation, and the water quality requirement is weak sulphuric acid solution or power plant desulfurization waste water (PH value 2 ~ 5), and the oyster shell is washed the soak time in pore-forming device and is 72 hours.

4. The active biological filter material for sewage treatment and the manufacturing method thereof according to claim 1, wherein: the shape requirement of the oyster shell raw material is that the length is more than or equal to 50mm, the width is more than or equal to 30mm, and the shell thickness is more than or equal to 2 mm; the oyster shell raw material comprises 39-41% of calcium, 26-28% of iron, 12-12.8% of manganese, 7.9-8.4% of zinc, 6-7% of strontium, 2.3-2.5% of nickel and less than 2.3% of copper.