System and method for recycling carbon, nitrogen and phosphorus resources by cracking excess sludge through microwave assisted by wave absorber

Abstract

The invention discloses a system and a method for recycling carbon, nitrogen and phosphorus resources by cracking excess sludge with microwave assisted by a wave absorber, and relates to the field of sludge treatment and recycling. The system comprises a mixing tank, a microwave cracking chamber, an anaerobic digester, a centrifugal separation device, a gas storage cabinet, a mechanical dehydration room, a carbonized sludge preparation chamber and a chemical sedimentation tank. The method comprises the following steps: mixing residual sludge and a wave-absorbing substance in a mixing tank, conveying to a microwave cracking chamber for microwave treatment, then digesting in an anaerobic digestion tank, collecting biogas in a gas storage cabinet, conveying an obtained sludge-water mixture to a centrifugal separation device for solid-liquid separation, and conveying the separated sludge to a mechanical dehydration room to obtain dried sludge; then carrying out high-temperature treatment in a carbonized sludge preparation chamber to prepare carbonized sludge which is reused as a wave absorber, and conveying supernate after anaerobic digestion to a chemical sedimentation tank to recover nitrogen and phosphorus. According to the method, after carbon, nitrogen and phosphorus resources are effectively released, the released resources are recycled by using methods such as anaerobic digestion and magnesium ammonium phosphate precipitation, so that sludge recycling is realized.

Description

technical field [0001] The invention relates to the technical field of sludge treatment and resource utilization, in particular to a system and method for recovering carbon, nitrogen, and phosphorus resources by using microwaves to decompose excess sludge with the aid of microwave absorbers. Background technique [0002] As a by-product of the urban sewage treatment process, excess sludge captures 65% to 80% of carbon, 20% to 40% of nitrogen, and 80% to 90% of phosphorus in sewage, so excess sludge has a high degree of available value. Under the strategic background of "carbon peaking and carbon neutrality", it is of great strategic significance to utilize carbon resources by reducing energy-based carbon emissions, controlling fugitive carbon emissions, and increasing carbon compensation. In the era of global resource scarcity, nitrogen and phosphorus elements, which are essential nutrients for crop production, are also the "culprits" of water eutrophication. Utilizing nitr...

AI Technical Summary

Problems solved by technology

Although the traditional anaerobic digestion system can achieve sludge stabilization and harmlessness, due to the different metabolic speeds of acidifying bacteria and methanogens, the accumulation of volatile fatty acids (VFAs) produced leads to an increase in hydrogen partial pressure, which is prone to production Serious problem of reduced gas rate or even gas production stop

At the same time, in order to pursue higher methane production, the sludge after anaerobic digestion usually has poor mud dehydration performance and high water content, which is not conducive to subsequent treatment and disposal.

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