Sewage treatment process and system

摘要

A sewage treatment process is provided, which includes the following steps: a) sewage feeding step, comprising introducing raw sewage into a biological reaction tank (1) to a predetermined time or liquid level; b) reaction step comprising performing aeration and stirring intermittently in the biological reaction tank (1); c) treated water discharging step, comprising performing solid-liquid separation of the mixed liquid in the biological reaction tank (1) by a membrane separation device (2) to obtain a first permeate, which is taken as the final treated water; d) standby step comprising stopping aeration in the biological reaction tank (1); and e) phosphorus-enriched water discharging step, comprising keeping anaerobic condition in the biological reaction tank (1) and performing solid-liquid separation of the mixed liquid in the biological reaction tank (1) by a membrane separation device (2) to obtain a second permeate, the second permeate entering inside a phosphorus recycling unit (5) which is set independent from the biological reaction tank (1), the phosphorus recycling unit (5) removing phosphorus from water, the second permeate becoming low-phosphorus water, and the low-phosphorous water flowing back to the biological reaction tank (1); the sewage treatment process runs in cycle by repeating above steps. A corresponding treatment system is also provided.

主权项

1. A sewage treatment process, comprising the following steps:
a) sewage feeding step, comprising introducing raw sewage into a biological reaction tank to a predetermined time or liquid level; b) reaction step, comprising performing aeration and stirring intermittently in the biological reaction tank; c) treated water discharging step, comprising performing solid-liquid separation of the mixed liquid in the biological reaction tank by a membrane separation device to obtain a first permeate, which is taken as the final treated water; d) standby step, comprising stopping aeration in the biological reaction tank; and e) phosphorus-enriched water discharging step, comprising keeping anaerobic condition in the biological reaction tank and performing solid-liquid separation of the mixed liquid in the biological reaction tank by a membrane separation device to obtain a second permeate, the second permeate entering inside a phosphorus recycling unit which is set independent from the biological reaction tank, the phosphorus recycling unit removing phosphorus from water, the second permeate becoming low-phosphorus water, and the low-phosphorus water flowing back to the biological reaction tank; the sewage treatment process runs in cycle by repeating above steps.