A phosphorus recovery reactor

Abstract

The invention relates to the field of environmental engineering water treatment machinery, in particular to a phosphorus recovery reactor. In the present invention, the feed inlet and the water inlet are designed to be crossed up and down, so that the calcium silicate hydrate crystals can be fully mixed and reacted with phosphorus-containing wastewater as soon as they enter the reactor, which improves the use efficiency of the crystals and has a higher phosphorus content. Recovery efficiency (the phosphorus content of phosphorus recovery products is generally greater than 15%). The reactor can assist the biological phosphorus removal system to realize the recovery of phosphorus resources. The combination of return hole and spoiler baffle makes the solid-liquid separation effect obvious and reduces the chance of crystal loss. In addition, the bell mouths located on the top of the inner and outer cylinders can make a small amount of overflowing crystals re-settled back into the reactor, further ensuring that the crystals are not lost. The invention realizes the recycling of crystals under the fluid state condition, the whole system can be operated automatically, the operation energy consumption is low, and the operation is simple and convenient.

Description

technical field [0001] The invention relates to the field of environmental engineering water treatment machinery, in particular to a phosphorus recovery reactor. Background technique [0002] Phosphate rock is an important non-metallic resource of strategic significance, mainly used in the production of phosphate fertilizer, phosphoric acid and phosphorus chemical products. In 2007, the Ministry of Land and Resources listed phosphate rock as one of the important minerals that cannot meet the needs of national economic development after 2010. According to statistics, it is predicted that the amount of phosphorus discharged from point sources in the Yangtze River Basin in 2020 will be 12.3×10 4 t or so, an increase of nearly double that of 2003. Assuming that the annual growth rate of sewage discharge is controlled at about 3%, the sewage discharge in the Yangtze River Basin will reach 447×10 8 t, it is preliminarily estimated that the daily sewage treatment capacity will r...

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Problems solved by technology

The current crystallization phosphorus recovery technology mainly recovers phosphate in wastewater in the form of struvite (MAP) or hydroxyapatite (HAP), which has the following shortcomings: (1) Phosphorus is recovered in the form of MAP, It is necessary to provide sufficient magnesium sources, which cannot be realized in inland areas where magnesium sources are relatively scarce, and will undoubtedly increase actual operating costs; (2) Recover phosphorus in the form of HAP. In the HAP system, supersaturation phenomenon is common, although maintaining A high pH value (>10.5) is a necessary condition for the formation of HAP, but it is worth noting that the high pH value environment not only makes it difficult to coordinate the chemical phosphorus removal (recycling) system and the sewage biological treatment system, but also increases the cost of chemical treatment. Reduce the composition of effective phosphorus in phosphorus recovery products; (3) When recovering phosphorus in the form of HAP, when the surface of the crystal is covered with HAP, due to the coating effect of the dense pore structure of HAP on the crystal particles, the crystal no longer has the ability to dissolve calcium and release alkali capacity, which limits the phosphorus recovery performance of crystal particles; (4) Due to the presence of carbonates in wastewater, the current HAP phosphorus recovery reactor often suffers from fouling due to the large amount of by-product calcium carbonate generated during the phosphorus recovery process Phenomenon, causing blockage of the reactor tube wall; in order to avoid the impact of the existence of carbonate on the phosphorus recovery efficiency, the existing technology often blows off CO by adding chemicals to reduce the pH value and aeration. 2 , and then add lye to maintain the pH in an alkaline environment to realize the phosphorus recovery process, which will inevitably increase the operating cost in actual operation; (5) the existing phosphorus recovery reactor, due to no effective solid-liquid separation measures, Phosphorus recovery crystal particles are often lost with the effluent flow, resulting in waste of crystals and affecting the phosphorus recovery effect

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