OVERVIEW:
The Hung Vinh Water Plant (2), with a capacity of 40,000 m3/day and the Nghe An Water Supply Joint Stock Company is owner. It was constructed in 2004 with funding from the Asian Development Bank (ADB). It plays a vital role in supplying clean water to Vinh City, Nghe An Province, and surrounding areas. Despite stable water quality, turbidity increases during the rainy season.
Recent rapid urban and industrial development in Vinh City has increased demand for clean water, exceeding the plant’s designed capacity. Nghe An Water Supply Joint Stock Company decide to upgrade the treatment process with TK+ technology solutions. The capacity from 40,000 m3/day to 96,000 m3/day using TK Plate settler®, TK Sludge Collector®, and flocculation agitator. The project, initiated in January 2020, has successfully met investor expectations.
CASE STUDY:
Before uprating, the Hung Vinh Water Plant had a nominal design capacity of 40,000 m3/day but was operating at over 50,000 m3/day. The basic technological process included:
- Inlet distribution tank
- Flocculation (hydraulic) to form flocs
- Horizontal sedimentation
- Rapid gravity filtration
- Reservoir
Raw water was sourced from the Lam River with turbidity ranging from 40 to 400 NTU (up to 1000 NTU during the rainy season) and pH levels between 6.3 and 6.9. Treatment chemicals used were PAC for flocculation, lime for pH adjustment, and chlorine for disinfection.
In the flocculation process, hydraulic mixing was employed, and the water flowed through baffles to form larger flocs. However, the efficiency was compromised due to insufficient mixing energy.
The sedimentation tanks consisted of 6 conventional horizontal tanks, each with dimensions of 30m x 5.4m. Post-sedimentation turbidity often exceeded 5 NTU due to overloaded operation.
Settled water was distributed to 6 filtration tanks through DN600 pipes. The filtration tanks utilized mono – layer rapid gravity filtration and collected clean water through nozzles. The filtration rate was 8-10 m3/m2.h, and the filtered water quality met the requirements, although the filtration cycle was short (24 hours).
Sự tham gia của TK+
TK+ actively recognized the need to increase the client’s processing capacity. We conducted surveys, evaluated the current situation, and proposed the “Design and Construction of the Hung Vinh Water Plant” to increase capacity from 40,000 m3/day to 96,000 m3/day.
TK+ performed the following tasks:
- Calculated and verified the hydraulic scheme and technological process of the Plant for a maximum capacity equivalent to 96,000m3/day.
- Added hydraulic baffles and expanded the reaction process with agitators to meet the 96,000 m3/day capacity.
- Upgraded the sedimentation process using TK Plate settler® technology to increase capacity without affecting the existing structure.
- Installed the TK Sludge Collector® automatic syphon system to improve efficiency.
- Provided operation guidance and technology transfer.
The outcomes:
TK+ upgraded the existing flocculation tank based on hydraulic principles, combined with using the inlet of the sedimentation tank to install flocculation agitators and hydraulic baffles to extend the reaction zone, enhancing the efficiency of the flocculation process.
Within the sedimentation zone, 04 TK Plate® settling modules were installed in one compartment. The nominal design capacity was 4,000 m3/day/module, and the treatment capacity reached 16,000 m3/day, with a total capacity of 96,000 m3/day.
All the sludge generated during the treatment process was collected and removed using the TK Collector® system, completely submerged in the sedimentation tank.
The installation area and operation of the system covered the entire sedimentation sludge zone, optimizing the operation efficiency of the entire system within the sedimentation tank.
After the overhaul, the quality of the settled water remained stable, with turbidity between 1 – 2.5 NTU. The use of PAC at the plant decreased by more than 20% compared to before, and the filtration cycle increased to 52 hours with a capacity of up to 96,000 m3/day.
The Nghệ An Water Supply Joint Stock Company is highly satisfied with these results. They express their gratitude to the TK Plate® and TK Collector® technologies for bringing about unexpected success.
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