METHOD OF UPGRADING THE ACTIVATED SLUDGE PROCESS BASED ON FUNCTIONAL SUSPENDED CARRIERS IN THE WASTEWATER BIOLOGICAL TREATMENT PROCESS

Abstract

A method of upgrading the activated sludge process based on functional suspended carriers in the wastewater biological treatment process. The reaction zone of the original activated sludge process is divided into an aerobic zone, anoxic zone, first aerobic zone and second aerobic zone without increasing the footprint and extending the original process. A certain amount of functional suspended carriers is added in each reactor according to the treatment requirements, and influent diversion is used, in order to improve the pollutant removal performance of the modification process. Furthermore, the effluent quality can meet the requirements of discharge standards. This method is especially suitable for the upgrading of built wastewater treatment plants.

Claims

1. A method of upgrading the activated sludge process based on functional suspended carriers the wastewater biological treatment process, wherein comprising the following steps: activated sludge reactor is divided into anaerobic zone, anoxic zone, first aerobic zone and second aerobic zone by partition wall, in which functional biofilm carriers are added in anaerobic zone, while electrophilic suspended biofilm carriers are added in anoxic zone, first aerobic zone and second aerobic zone; influent diversion, in which the wastewater is fed from the front of anaerobic zone and anoxic zone respectively, is adopted to lead some wastewater into the anoxic zone, and avoid excessive consumption of influent carbon sources in the anaerobic zone due to feeding wastewater only from the anaerobic zone, and provide more carbon sources for heterotrophic denitrifying bacteria and denitrifying phosphorus accumulating bacteria, thus improving the performance of denitrifying phosphorus removal; the nitrate is refluxed from the end of the second aerobic zone to the front of the anoxic zone, and the reflux ratio is more than 50%; the reflux sludge is refluxed from the biochemical secondary settling tank to the front of the anaerobic zone, and the reflux ratio is more than 100%; the way of influent diversion: the influent diversion ratio, feeding to anaerobic zone and anoxic zone, is 1:0.25-4.

2. The method of upgrading the activated sludge process based on functional suspended carriers in the wastewater biological treatment process according to claim 1, wherein, the percentage of added functional biofilm carriers in the anaerobic zone is less than 50% of the effective volume of the anaerobic zone; and the percentage of electrophilic suspended biofilm carriers in the anoxic zone, first aerobic zone and second aerobic zone is less than 50% of the effective volume of each reactor.

3. The method of upgrading the activated sludge process based on functional suspended carriers in the wastewater biological treatment process according to claim 1, wherein, mechanical stirring is used in the anaerobic zone and anoxic zone, while microporous aeration is used at the bottom of the first aerobic zone and second aerobic zone, in order to obtain the full mixing of wastewater-suspended carrier-activated sludge-oxygen in each reactor.

4. The method of upgrading the activated sludge process based on functional suspended carriers in the wastewater biological treatment process according to claim 2, wherein, mechanical stirring is used in the anaerobic zone and anoxic zone, while microporous aeration is used at the bottom of the first aerobic zone and second aerobic zone, in order to obtain the full mixing of wastewater-suspended carrier-activated sludge-oxygen in each reactor.

Description

DETAILED DESCRIPTION

[0015] Detailed embodiments of the present invention are described below in conjunction with the technical solutions.

Embodiment 1

[0016] The upgrading and expansion methods of municipal wastewater treatment plants are as follows: (1) the effective volume ratio of anaerobic zone, anoxic zone, aerobic zone 1 and aerobic zone 2 was 1:2: 2: 2; (2) the influent diversion ratio of feeding to anaerobic zone and anoxic zone respectively was 1: 1; (3) the reflux ratio of nitrate and reflux sludge were 100% and 50%, respectively; (3) the functional carrier content of the anaerobic zone, anoxic zone, aerobic zone 1 and aerobic zone 2 accounted for 15%, 30%,30% and 45% of the effective volume of each reactor, respectively. (4) the hydraulic retention time of anaerobic zone, anoxic zone, aerobic zone 1 and zone 2 were 2, 4, 4 and 4 hours respectively; (5) the dissolved oxygen concentration in anaerobic zone and anoxic zone were below 0.1 mg/L, while that value in aerobic zone 1 and aerobic zone 2 were maintained at 2-3 mg/L. The operation results showed that compared with the original activated sludge process, the wastewater biological treatment process based on functional suspended carrier not only shortened the hydraulic retention time (6 hours shorter than the original activated sludge process) and increased the removal rates of COD, NH.sub.4.sup.+N, TN and TP by more than 20%, 45%, 35% and 25% respectively, but also made the effluent quality meet the requirements (COD<50 mg/L, NH.sub.4.sup.+N<5 mg/L, TN<8 mg/L, TP<1 mg/L) of Class I (A) of Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant of China (GB18918-2002).

Embodiment 2

[0017] The upgrading and expansion methods of industrial wastewater treatment plants are as follows: (1) the effective volume ratio of anaerobic zone, anoxic zone, aerobic zone 1 and aerobic zone 2 was 1:2: 2: 1; (2) the influent split ratio of feeding to anaerobic zone and anoxic zone respectively was 1: 2; (3) the reflux ratio of nitrate and reflux sludge were 200% and 100%, respectively; (4) the functional carrier content of the anaerobic zone, anoxic zone, aerobic zone 1 and aerobic zone 2accounted for 20%, 30%, 40% and 40% of the effective volume of each reactor, respectively. (5) the hydraulic retention time of anaerobic zone, anoxic zone, aerobic zone 1 and zone 2 were 8, 16, 16 and 8 hours respectively; (6) the dissolved oxygen concentration in anaerobic zone and anoxic zone were below 0.1 mg/L, while that value in aerobic zone 1 and aerobic zone 2 were maintained at 3-4 mg/L. The operation results showed that compared with the original activated sludge process, the wastewater biological treatment process based on functional suspended carrier not only shortened the hydraulic retention time (16 hours shorter than the original activated sludge process), but also increased the removal rates of COD, NH.sub.4.sup.+N, TN and TP by more than 20%, 45%, 35% and 25% respectively.