In order to comply with the more restricted effluent standards announced in 1998.1.1 by the Environmental Protection Agency, Executive Yuan, the Dihua Sewage Treatment Plant History stopped operations in 1998.4.7 for upgrading to a Class-2 process, the upgrading project mainly comprised of civil works, treatment systems and landscaping. The entire project was completed in November 2006 and formal operations started in February 2007. Sludge reducing equipment was completed in 2014.

Sewage is treated by deep chamber staged aeration Class-2 biological treatment followed by disinfection before discharging into the Tamsui River; sludge is treated by thickening, anaerobic digestion and dehydration and then hauled by an entrusted legal removal service provider to the EPD’s incinerator in Taipei City for incineration.

1. Design Capacity: Daily Average sewage treatment 500,000CMD
2. Design Quality:
   • Intake Sewage: BOD5 = 180mg/L, SS = 180mg/L;
   • Effluent Quality: BOD5≦20mg/L, SS≦20mg/L.
3. Recycled Water for re-use: Design capacity: 10,000CMD

1. After entering the Dihua Sewage Treatment Plant, large solids in the diverted sewage are first removed by a Fine Bar Screen, most precipitable suspended solids are then removed by a Primary Clarifier. Effluent from the Primary Clarifier then enters the aeration chamber and secondary clarifier for removing organics. Sodium hypochlorite is finally added to remove germs and effluent before it is discharged into Tamsui River. A 10,000CMD portion of the effluent is further treated by sand filter for recycled use.
2. As for the manure, together with thickened sludges from primary and secondary clarifiers, it is treated by anaerobic digestion and dehydration to from sludge cakes. The cakes will be further used for multiple purposes after completion of the plant’s sludge reduction project, such as for incineration, brick making, road foundation material, cement additive, etc.
3. Gas produced in the Anaerobic Digest Chamber is recycled for re-use; in addition to being used for stirring the digest chamber itself and fueling the boiler for maintaining temperature of the chamber, the rest is used as heating energy for the sludge dryer system.

1. The plant’s main treatment unit is a 210m x 250m installation in a 17m depth under the ground, daily capacity 500,000CMD, the biggest Class-2 sewage treatment facility in Taiwan.
2. The main unit includes: intake preliminary treatment, primary clarifier, deep-trough aerator, secondary clarifier, disinfection chamber, and effluent pumping station. All of them are enclosed semi-underground structures. Additional facilities include a deodorizing system and noise insulation for minimizing negative effects to the surroundings.
3. Both the primary and secondary clarifiers adopt a double layer design which is first seen in Taiwan, enabling higher treatment capacity in a limited floor area. Additionally, the biotreatment of deep trough staged aerator is also the initial application in Taiwan; besides general biotreatment, it also provides nitrogen removal.
4. The plant is equipped with Class-3 recycling facility (automatic backwash sand filter) for supplying water for washdowns and irrigation use within the plant and horticulture use of the public.
5. The top area of the main treatment unit has a coverage of 4.6 hectares, i.e., 13,900ping, providing versatile leisure facilities such as children’s playground, skating rink, lawn activity area, basketball court, tennis court, softball field, parking lot and public arts for public use.

After its upgrading to a Class-2 plant, the Dihua Sewage Treatment Plant not only improved its effluent quality that meets stricter effluent standards, but also significantly lowered the risks of the enlarge system. Furthermore, the integral design made optimum use of the land: a 500,000CMD sewage treatment plant is built on the original land, a nearly 100% increase to the original capacity, plus with a leisure park installation on the top, providing facilities for leisure activities for the citizens.

Being the largest Class-2 sewage treatment plant in Taiwan, the operations of the Dihua Sewage Treatment Plant started in 2006 on its completion. Daily capacity can be as high as 500,000CMD; and after its commencement, the water quality of the Tamsui River has turned from medium to low polluted from the original heavily polluted.

The Dihua Sewage Treatment Plant employs a double-layer clarifier design (which is the first in Taiwan) and a deep chamber staged aeration Class-2 biological treatment procedure; a semi-underground design concept is used for the entire plant for preventing dispersion of odors generated by sewage treatment; and an additional Class-3 recycling facility is installed for supplying water to in-plant facilities and toilets as well as to the public for plant irrigation use, street washdowns, and so on.

• Plant address: No. 235, Jiuquan Street, Datong District, Taipei City
• Tel: (02) 2596-9616
• Fax. (02) 2596-4463

Sewage Treatment Procedures:

Dihua Sewage Treatment Plant Main Treatment Facilities List

Address of Dihua Sewage Treatment Plant: No. 235, Jiuquan Street, Datong District, Taipei City. Certified as an “Environment Education Facility” on March 25th 2004 by EPA, the very first urban sewage education locality in Taiwan.

“Water Protection, Culture and Industry” are 3 aspects of environmental education courses promoted by the Dihua Sewage Treatment Plant addressing different groups: primary school students, junior-high students, and the general public (including high school students); courses include contents regarding sewage treatment education: “New Dress for Sewage Baby” and “Knowing Sewage Treatment System;” “Tales of Water Babies,” “The encounter between Nature and Culture” that link with the local culture and public arts; legacy carved in Taipei residents’ hearts – Tamsui River anecdote that accompanied their growth are also included in “The place we grew up,” “Water Stories of Taipei;” together with some hands-on activities, the course becomes more colorful and vivid. Each 2-hour course may accommodate 25 people. Reservation is open 9:00-17:00 on normal days (Monday through Friday). On-line reservation is prioritized for citizens and entities. Website: https://service.gov.taipei/rental/VenueDetail/e1fabfea2753. People may query for detains via Fax: 2596-4463, letter, or telephone (02-25973183 extension 871). Courses are introduced as follows:

Sewage treatment is an unfamiliar realm to the general audience; via visitation to a sewage treatment plant participants may learn how does sewage come about and why a sewage treatment plant is necessary for treating domestic sewage so that impact to the environment can be minimized; they may also realize only via water conservation and re-use of recycled water can we achieve sustained operations of water resources.

Furthermore, games that combine with process activities, pH value test and sludge sedimentation test (SV30) may also enable participants to have preliminary understanding in sewage treatment technologies; via observing the treated wastewater, one may also realize the importance of sewage treatment plants.

This course aims to give an understanding of coexistence of human and environment via public arts at the Dihua Sewage Treatment Plant and to learn to appreciate man-made beauties; by introducing “The Esthetics of Contacts,” “Hearing the Water” and “Ground Revelation,” students may understand the origin of sewage and the process for its treatment and return to the nature.

Explaining river pollution indices and comparing past and current pollution conditions of the Tamsui River by actually visiting the waterfront and the effluent location, students are enabled to understand the necessity of a sewage treatment plant.

Construction of Neihu Sewage Treatment Plant mainly includes civil work, treatment system and landscaping; where the main construction started on February 13, 1998. The Design Volume of Phase-1 sewage treatment was 150,000CMD. The Sewerage Systems Office itself started its operation after the successful acceptance inspection on July 22, 2004. The Design Volume of Phase-2 sewage treatment was 240,000CMD; the expansion was completed for operations in 2016. The operations, maintenance and management of the plant was outsourced since July 1, 2020,

The original design of the Class-2 treatment unit is of the VIP Method, which is capable of effective removal of nitrogen and phosphorus; currently we have changed active sludge treatment unit into step-type VIP method. The Class-2 treated water is discharged into the Keelung River after sodium hypochlorite disinfection, a portion of the treated water undergoes circulation of mechanical filtration and Ultrafiltration (UF) for recycled use.

1. Design Intake Flow: 240,000CMD
2. Design Intake Quality:BOD₅: 185mg/L ,SS: 190mg/L
3. Effluent quality:BOD₅≤30mg/L、SS≤30mg/L
4. Recycled Water:Design Capacity: 20,000CMD，Ultrafiltration (UF) System: 200CMD Design Capacity

1. After entering the plant, the sewage passes through a Bar Screen and Sedimentation Pool for removing debris, sand and gravel from the water protecting pumps; it then enters the Primary Clarifier for removing part of organic substances and most suspended solids from the water.
2. The supernatant from the Primary Clarifier then enters the Class-2 Biotreatment Unit (in Stepped VIP) and then the Secondary Clarifier, for sedimentation; after that, the treated water is disinfected with sodium hypochlorite to remove germs and becomes the effluent before being discharged into the Keelung River.
3. Effluent from the Class-2 biotreatment is disinfected with sodium hypochlorite; part of it is filtered by automatic filters and the Ultra-Filtration System for recycled use in the plant, as well as for external use, for maximum recycling .
4. Starting from 2007, scum and sludge separated from the primary and secondary clarifiers have been incorporated into the process of the Dihua Sewage Treatment Plant via a dedicated pipeline and sieve dregs are hauled to incinerators for incineration.
5. In order to prevent odors of hydrogen sulfide and ammonia from affecting operators in the plant and causing air quality and environmental issues to nearby residents, the exhaust gas is collected with ducts and treated by wet chemical cleansing and odor removal facilities before being released into the atmosphere, thereby complying with air quality requirements of the environment.

1. The Neihu Plant is the first semi-underground sewage treatment plant in Taiwan designed using a concept of a totally covered configuration that can prevent odors produced by treatment facilities from escaping and dispersing.
2. The superstructure of the plant, an area of 3.8 hectare, is programmed as a sports park equipped with pools, PU tracks, extreme sport facilities, rock climbing field, children’s playground, and even models of the sewage treatment plant for demonstrating its procedures, which may benefit leisure activities of citizens and emphasize environmental education for the public.
3. Suggestions are made for using recycled water for flushing the toilet, for cleaning public environments, for irrigating plantations and maintaining landscaping, for washing large vehicles, for sprinkling roads to eliminate flying dust, thereby setting examples in re-using the recycled water.

Ever since the completion and start of its operations, the project has not only alleviated the load of centralized treatment for the sewerage systems in Taipei City but also functioned to supplement the flow of the Keelung River for increasing its self-cleaning capability and volume accommodating capacity.

The construction of the Neihu Sewage Treatment Plant started in February 1998. After completion and successful function test in May 2003, the plant entered formal service and operations in 2004. The design capacity of Phase-1 construction was 150,000CMD; after completion of the Phase-2 construction in 2016, the design capacity increased to 240,000CMD.

It mainly functions for handling the sewage of Neihu and Dazhi areas and part of New Taipei City’s Xizhi area, and for regulating sewage flow of the Xizhi-Nangang Trunk; via the cross Keelung River connection pipeline, it also exerts an interactive flow regulation with the Dihua Plant by sending sludge to Dihua Plant for centralized treatment and for lowering the cost.

The Neihu Plant adopts Class-2 Biotreatment, where treated water is discharged into the Keelung River after sodium hypochlorite disinfection; part of treated water is recycled for re-use after passing through a mechanical filter system and Ultrafiltration (UF) system, used for washdown and irrigation within the plant as well as for civilian plantations and street washdowns.

A sports park of 3.8 hectare area is established, facilities include public arts, water pools, rock climbing field, extreme sports setup, etc.

• Plant Address: No.2, Jiuzong Road Sec. 2, Neihu District, Taipei City
• Tel: (02)87919494
• Fax: (02)87919746

1. After entering the plant, the sewage passes through a Bar Screen and Sedimentation Pool for removing debris, sand and gravel from the water protecting pumps; it then enters the Primary Clarifier for removing part of organic substances and most suspended solids from the water.
2. The supernatant from the Primary Clarifier then enters the Class-2 Biotreatment Unit (in Stepped VIP) and then the Secondary Clarifier, for sedimentation; after that, the treated water is disinfected with sodium hypochlorite to remove germs and becomes the effluent before being discharged into the Keelung River.
3. Effluent from the Class-2 biotreatment is disinfected with sodium hypochlorite; part of it is filtered by automatic filters and the Ultra-Filtration System for recycled use in the plant, as well as for external use, for maximum recycling .
4. Starting from 2007, sludge separated from the primary and secondary clarifiers have been incorporated into the process of the Dihua Sewage Treatment Plant via a dedicated pipeline and sieve dregs are hauled to incinerators for incineration.
5.  In order to prevent odors of hydrogen sulfide and ammonia from affecting operators in the plant and causing air quality and environmental issues to nearby residents, the exhaust gas is collected with ducts and treated by wet chemical cleansing and odor removal facilities before being released into the atmosphere, thereby complying with air quality requirements of the environment.

Facility Floorplan
Main Treatment Facilities List

Item	Facility Name	Quantity	Description
1	ADM Building	1	L 52m, W 25m, above ground H 14m 3 levels above ground, 1 level underground
2	Mechanical Coarse Bar Screen	4	Horsepower: 5 HP Pitch: 50/38 mm Channel Width: 2.2 m Voltage: 3-ph, 380 V, 60 Hz Type: Rack-type and rotary type bar
3	Intake Pump	5	Horsepower: 500 HP (350 kW) Lift: 18.5 M Flow Rate: 83.4 M3/min Rotation Speed: 710 RPM Voltage: 3-ph, 6.9 KV, 60 Hz
4	Bypass Pump	2	Horsepower: 500 HP (350 kW) Lift: 18.5 M Flow Rate: 83.4 M3/min Rotation Speed: 710 RPM Voltage: 3-ph /6.9 KV /60 Hz
5	Mechanical Fine Bar Screen	5	Horsepower: 5 HP Pitch: 6 mm Channel Width: 2.2 m Voltage: 3-ph /380 V/60 Hz Type: Rotational self-clean bar type
6	Primary Clarifier	8	Pool Size: L 56m, W 11.5m, D 4m Overflow Rate: 47.6CMD/㎡ Each pool has longitudinal chain scraper and scum collection device
7	Centrifugal Blower	8	Horsepower: 600 HP（450 kW） Rated air flow: 270 m3/min Rated pressure: 765 mbar Rotation Speed: 3550 RPM Voltage: 3-ph/6.9 KV/60 Hz
8	Roots Blower	3	Horsepower: 150HP Rated air flow: 70 m3/min Rated Pressure: 0.6 kg/cm2 Rotation Speed: 1450 RPM Voltage: 3-ph/ 380 V/60 Hz
9	Bioreactor	12	Pool size: L 58m, W 6m, D 6.5m Step VIP method is used Hydraulic retention time 5.7h
10	Secondary Clarifier	16	Pool Size: L 50m, W 11.5m, D 5m. Overflow Rate: 33 CMD/㎡ Solid load rate: 3.9 kg/㎡/h Each pool has longitudinal chain scraper and scum collection device
11	Chlorination Disinfector	2	Contact Chamber Canal: L 120m, W 3.5m, D4m Contact chamber canal: L 120m, W 3.5m, D4m Dosing Tank: RC tank x3, 8m×4m×3.5m Hydraulic Retention time: 0.8min (mixing tank), 30min(Contact Chamber Canal) Dosing Tank Capacity: 120m3
12	Effluent Pumping Station	1	Wet Well L 14.5m, W 14.2m, D 4.7m Pump x4, 120,000CMD each Gate x3, moisture-proof tongue valve
13	Effluent Pump	4	Horsepower: 350 HP Lift: 11.7 M Flow Rate: 83.4 M3/min Rotation Speed: ≦1200 RPM Voltage: 3-ph/6.9KV/60Hz
14	Recycle Pumping Station	1	Wet Well L 20.8m, W 20.5m, D 6m Pump x5, 2,000CMD each Automatic Filter x2
15	UF System	2	Design Flow: 100 CMD Pore Dia.: 0.04 uM Voltage: 3-ph/380 V/60 Hz
16	Sludge Thickener	3	Each with belt-filter concentrator, belt width 2m Operating Method: Continuous 16h/d Concentrate Sludge: SS content≧50,000mg/L Solid Capture Rate: ≧95%
17	Sludge Dehydrator	3	Each with belt-filter concentrator, belt width 2m Operating Method: Continuous 16h/d Dehydrated sludge cake: SS content ≧200,000mg/L Solid Capture Rate: ≧95%
18	Deodorizing Chamber	2	Deodorization Chamber (I): L 26.3m, W 18.3m, H 18.6m Remove all the organic and inorganic odor produced in the plant area 2-stage horizontal cross-flow scrubber x2
19	Sub-station and Power Generator Room	1	L 40.8m, W 24.7m Diesel Generator x4 For providing emergency power and lighting in the plant area Diesel Generator in parallel connection, (1500kW 6.9kV 60Hz)