CN103449559A - Method and application for using building abandoned cement brick as dephosphorization filler - Google Patents

Abstract

A phosphorus-removing adsorbent for treating low-concentration phosphorus-containing eutrophic water bodies. The patent of the present invention relates to a phosphorus removal adsorbent, which is characterized in that broken cement bricks are used as fillers for adsorption and removal of phosphorus. The invention utilizes waste cement bricks from construction to form small particle adsorbents after crushing, which can effectively reduce the concentration of phosphorus in the water body. Compared with other commonly used adsorbents, this adsorbent is especially effective in reducing low-concentration phosphorus-containing water. Cement bricks are an inexpensive and high-performance adsorbent. It can be widely used in the treatment of eutrophic water bodies, and it also opens up the field of cement bricks used as construction waste resources.

Description

A method and application of building waste cement bricks as phosphorus removal filler

technical field

The patent of the present invention relates to the application of cement bricks in the treatment of eutrophic water bodies. It belongs to the field of water pollution control.

Background technique

Eutrophication refers to the large amount of nutrients such as nitrogen and phosphorus required by organisms entering slow-flowing water bodies such as lakes, estuaries, and bays, causing algae and other plankton to multiply rapidly, the dissolved oxygen in the water body decreases, and fish and other organisms die in large numbers. Phenomenon. The development trend of eutrophication of lakes, reservoirs and rivers in our country is very rapid. From 1978 to 1980, most of the lakes were in the mesotrophic state, accounting for 91.8% of the surveyed area, 3.2% in the oligotrophic state, and 5.0% in the eutrophic state. In just 10 years, most of the oligotrophic lakes have transitioned to mesotrophic lakes, and the proportion of the evaluated area of oligotrophic lakes has dropped rapidly from 3.2% to 0.53%. The proportion of evaluation area increased sharply from 5.0% to 55.01%.

In the past few decades, ecological restoration has been widely used to remove nutrients (especially nitrogen and phosphorus), organic matter and heavy metals in water, and has become one of the important measures to improve water pollution. One of the difficulties in purifying eutrophic water is phosphorus removal. Phosphorus in water is accomplished through the adsorption and precipitation of substrates, absorption by microorganisms and plants, etc. Among them, the adsorption of substrates is the most important way to remove phosphorus; although plants and microorganisms can absorb a part of phosphorus, the way The phosphorus removed represents only a small fraction of the phosphorus in the water body. Therefore, the matrix plays a very important role in the phosphorus removal process. The removal effect and mechanism of different substrates in water bodies with different phosphorus concentrations will show different characteristics, and the adsorption capacity of substrates is the limiting factor for phosphorus removal. Substrates have different adsorption capacities for water bodies containing phosphorus in different concentrations, and the adsorption characteristics of substrates with strong adsorption capacity under high concentration conditions are obviously different in water bodies containing phosphorus in low concentrations. Under laboratory conditions, cement bricks have been studied in detail, and it is found that they have good purification ability for low-concentration phosphorus-containing water, which is mainly due to the high content of calcium, aluminum and iron in cement bricks.

Therefore, it is one of the effective measures to find a cheap and effective adsorbent for phosphorus removal to treat eutrophic water bodies.

Contents of the invention

The invention provides a phosphorus-removing adsorbent for treating eutrophic water bodies. Solve the problem of eutrophication and the reuse of construction waste cement bricks.

The technical scheme of the present invention: firstly, the cement bricks are broken, and the broken cement bricks are used as fillers to contact with the eutrophic water body, and the concentration of phosphorus in the water is reduced through the adsorption of the cement bricks. The bricks are construction waste cement bricks, the main components of which are cement and river sand after analysis, and are rich in materials such as silicates and calcium salts. After several tests, it is shown that the adsorbent is very effective in removing low-concentration phosphorus in water.

The cement brick prepared by the invention has loose structure after crushing, large porosity, good hydraulic conductivity and large specific surface area, is an excellent filler, and has the functions of microbial carrier and phosphorus adsorbent.

The cement brick as an adsorbent provided by the invention has the characteristics of good adsorption performance, simple operation, no secondary pollution, low cost, and environmental protection. It is a common and cheap adsorption and phosphorus removal material, and the removal rate of phosphorus in water can reach 90%. above. It can be widely used in the treatment of eutrophic water bodies, and it also opens up the field of cement bricks used as construction waste resources.

Description of drawings

Fig. 1 and Fig. 2 are the schematic diagram of the cylinder of the patent of the present invention and the schematic diagram of the artificial wetland filler respectively.

Detailed ways

First, cement bricks, which are construction waste, are broken.

Embodiment 1: Take 6 parts of bricks with a particle size of 5 mm and add 150 mL of potassium dihydrogen phosphate solution respectively, and the initial phosphorus concentration ranges are 0.5, 1, 2, 3, 4, 5 mg/L respectively. Shake on a constant temperature shaker at 25°C for 24h. According to the adsorption isotherm, the maximum adsorption capacity of cement bricks was calculated to be 0.644 mg-P/g-adsorbent. Under the same conditions for magnetite, the saturated adsorption capacity of cement bricks was significantly higher than that of magnetite ore by 0.158 mg-P/g-adsorbent.

Specific implementation mode 2: Use packed column to treat waste water containing low concentration phosphorus, adsorption column (as shown in Figure 1), the inner diameter of the adsorption column is 60mm, the effective height is 300mm, and the column is filled with cement bricks (particle size 5~10mm) In the adsorption column, the height of the effective packing layer is 300mm. The concentration of TP in the influent water is maintained at about 2mg/L, and the hydraulic load is 10cm/d. The column effluent concentration is maintained below 0.2mg/L.

Specific embodiment 3: This embodiment is described in conjunction with FIG. 2 , which is used as a constructed wetland to treat fillers containing low-concentration phosphorus river water. The rear section of the constructed wetland is filled with cement bricks, which play a role in phosphorus removal. The eutrophic river water containing low concentration of phosphorus will flow vertically into the cement brick section to ensure full contact between the cement brick and the filler. The hydraulic load of the wetland operation is 12cm·d ^-1 , the size is 2 m×0.6 m×0.4 m, the influent NH ₄ ⁺ -N is maintained at 10 mg/L, TN 20 mg/L, TP 2 mg/L, NH ₄ ⁺ -N and TN The removal rate can reach more than 90%, and the concentration of TP effluent is maintained at 0.5mg/L.

Claims (3)

1. A kind of waste cement brick filler that is used to process containing low concentration phosphorus water body, it is characterized in that using the granular cement brick after crushing as adsorbent. 2. The cement brick according to claim 1, as the application of filler in water treatment process. 3. cement brick according to claim 1, as the application of phosphorus removal sorbent in water treatment process.

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