Double-layer artificial wetland system for strengthening sewage denitrification and dephosphorization and operation method thereof

Abstract

The invention discloses a double-layer artificial wetland system for strengthening sewage denitrification and dephosphorization and an operation method thereof. The system comprises an upper layer of wetland, a lower layer of wetland, a water inlet and distribution system and an effluent collection system, wherein the upper layer of the wetland is filled with mineral filler, and the lower layer of the wetland is filled with biologic filler which is favorable for microorganisms to adhere to grow; the water inlet and distribution system is divided into to two branches, wherein one branch is distributed above the upper layer of the wetland, and the other branch is distributed on the interface of the upper layer of the wetland and the lower layer of the wetland; and the effluent collection system is distributed on the bottom of the lower layer of the wetland. The method comprises: waterfall aeration is carried out on sewage by one branch of the distribution system, then the sewage falls into the upper layer of the wetland to remove organic matters, ammonia nitrogen, phosphorus and the like to vertically seep into the lower layer of the wetland; in order to supplement a carbon source, a small strand of sewage is introduced into the lower layer of the wetland by the other branch of the distribution system to be mixed with the sewage seeped from the upper layer of the wetland for denitrification; and water is discharged from the effluent collection device after being processed. The invention occupies small area, has small possibility of being blocked and has favorable denitrification and dephosphorization effects and low investment operation cost.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a double-layer constructed wetland system for strengthening nitrogen and phosphorus removal from sewage and an operation method thereof. Background technique [0002] Sewage land treatment Constructed Wetlands (CWs) has become a water pollution control technology that has attracted worldwide attention. Constructed wetlands were first publicly reported in 1904, but officially as a sewage treatment technology, they emerged in the United States, Australia, the Netherlands, Denmark, the United Kingdom and other countries in the 1970s, and their rapid development took place in the past two decades. In recent years, studies on the application of constructed wetlands to treat domestic sewage in villages and towns, control agricultural non-point source pollution, and eutrophication of rivers and lakes have been frequently reported. [0003] However, the disadvantages of traditi...

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Problems solved by technology

[0007] In the past, there were the following problems in the research and application of constructed wetlands: wetlands dominated by soil or fine sand were easy to clog and the pollutant load was low; relying solely on plant reoxygenation had the problem of insufficient oxygen supply, and the removal effect of ammonia nitrogen was poor. Aeration also increases energy consumption and operating costs; insufficient carbon sources in the back section of the wetland lead to unsatisfactory denitrification and denitrification effects; the introduction of high-efficiency phosphorus removal fillers such as slag, steel slag, and quartz sand mainly relies on adsorption to remove phosphorus. On the one hand, the filler itself The physical and chemical properties of the wetland plants may have a negative impact on the growth of wetland plants. On the other hand, the replacement of the filler after adsorption saturation will lead to an increase in investment costs. The treatment and disposal of the filler after adsorption saturation has potential secondary pollution and other issues.

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