Energy neutral analysis of sewage treatment plant based on AB method under the background of carbon neutrality

doi:10.3969/j.issn.1674-1951.2021.06.007

Abstract

Abstract:

China's sewage treatment industry carbon emissions accounted for 1.0%~3.0% of the total emissions.Under the trend of carbon neutralization,it is necessary to fully tap the potential of sewage and realize the energy self-sustaining of sewage treatment.Chemical oxygen demand （COD） in wastewater contains a large amount of chemical energy.When COD is 1 mg/L,the chemical energy in 1 m³ wastewater is about 16.2 kJ,which is the main way of sewage energy utilization. Scholars in China and abroad have studied the new AB process based on carbon capture and carbon source modification,and proposed various characteristic energy balance or carbon neutralization technology routes.The theoretical calculation was carried out with the influent COD of 500 mg/L.Based on the AB process+anaerobic digestion+CHP power generation process,the power generation potential of 1 m³ wastewater was calculated to be about 0.340 kW·h,which can realize the energy self-sustaining of the operation of the wastewater treatment plant.In addition, the introduction of water source heat pump and photovoltaic power generation in sewage treatment plants is also an important supplementary means to realize energy self-sustainment.The waste heat contained in sewage can only be converted to a low grade heat source of about 60°C by water source heat pump,which cannot be directly used for power generation.Wastewater treatment plants use photovoltaic power generation to compensate for about 10.0% of energy consumption.

Key words: carbon neutral, adsorption-biodegradation process, chemical oxygen demand, combined heat and power, water source heat pump, solar power

CLC Number:

TK01 ⁺9：X703

LIANG Yuan, FU Yanfeng, FANG Xiaofeng, CHENG Hongyan, MENG Chunlin, YAN Yingying, CHEN Beiyang. Energy neutral analysis of sewage treatment plant based on AB method under the background of carbon neutrality[J]. Huadian Technology, 2021, 43(6): 55-60.

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项目	COD 比例/%	能量/（kW·h）	计算过程
污水进水	100.0	2.250×10⁵	（500×10×10⁴×16.2）/3 600
通过厌氧系统产生甲烷	43.0	0.970×10⁵	2.250×10⁵×43.0%
甲烷通过CHP 的发电量		0.340×10⁵	0.970×10⁵×35.0%
每m³污水的发电量		0.340	(0.340×10⁵)/(10×10⁴)