OVERVIEW:
Hoang Mai WTP is owned by Hoang Thinh Dat Company, a specialized investor in water supply and industrial infrastructure in Vietnam. The initial design capacity of the WTP was intended to be 30,000 m3/day, and KOBELCO ECO SOLUTIONS was selected as the EPC contractor.
The plant’s capacity is crucial to meet the clean water demand for the residents of Hoang Mai town, Nghe An province, and the Hoang Mai industrial zones owned by Hoang Thinh Dat.
Hoang Mai Water Plant utilizes surface water from Vuc Mau Lake, which has stable water quality. However, turbidity is relatively high during the rainy season.
The initial design of Hoang Mai WTP included hydraulic flocculation tanks, sedimentation tanks with PVC tube settlers, a sludge scraper system, and rapid gravity filtration using siphons, with a capacity of 30,000 m3/day. After reevaluating water demand and exploring technologies of TK Plate® Settler, TK Collector®, TK+ was chosen to uprate the sedimentation to 56,000 m3/day without altering the ongoing construction, due to its superior advantages in TECHNOLOGY, ECONOMICS, and EFFECTIVENESS.
CASE STUDY:
The Hoang Mai WTP is designed with a nominal capacity of 56,000 m3/day, employing the following basic technological process:
The raw water source is extracted from Lake Vuc Mau and exhibits the following basic quality:
- Turbidity: 10 – 200 NTU (may exceed 500 NTU during heavy rain).
- pH: 6.8 – 7.3.
- Treatment chemicals used include:
- PAC: for flocculation.
- Vôi: for pH adjustment.
- Chlorine: for disinfection.
In this project, TK Plate® settler was selected by Kobelco and approved by the investor, Hoang Thinh Dat Company.
The TK+ equipment was designed, fabricated, supplied, installed, and operated for the high-rate sedimentation system using TK Plate® Settler technology for 2 tanks measuring 8.15 m (width) x 17.00 m (length) x 4.50 m (depth), along with 02 syphon sludge collection systems without using discharge pipes (TK Collector®)..
The system design parameters are as follows:
- Design capacity: 56,000 m3/day.
- Number of settling tanks: 2 tanks.
- Design load: 24 m3/m2.day.
- Total settling modules/tank: 16.
- Settling capacity/module: 3,500 m3/day.module.
- Number of settling rows: 2 rows.
- Number of modules in each row: 4 modules.
- Number of modules per tank: 8 modules.
The supporting beam system is constructed using reinforced concrete by another construction contractor.
The structure of the settling module includes:
- Frame: SS304 stainless steel.
- Side plate: SS304 stainless steel.
- Settling plate: FRP (Fiberglass Reinforced Polyester).
- Surface water collection pipe: SS304 stainless steel.
- Adjusting plate: SS304 stainless steel.
- Collection trough: SS304 stainless steel.
- Screws & bolts: SS316 stainless steel.
The TK Collector® syphon sludge collection system includes:
A drive unit consisting of a gear reduction gearbox operated by a 1/2 HP TEFC electric motor with constant torque installed on a mechanical hoist frame with adjustable dimensions, a drive pulley system, and a protective box.
A stainless steel 304 drive rail system with anchoring base and materials for secure attachment to the floor using chemical bolts.
A stainless steel 304 cable system capable of pulling the sludge collector head the full length of the settling tank.
A sludge collector head comprising a D300mm (12”) central pipe with 2 DN100mm (4”) sludge suction heads made of stainless steel 304 with multiple small suction holes arranged to clean sludge on the settling tank floor. Sludge suction heads are fitted with plastic base feet to minimize jamming during movement.
A DN100 pneumatic on/off valve installed at the tank discharge end to periodically discharge sludge according to the operator-set cycle.
A control cabinet with a double-layer stainless steel outdoor enclosure installed on the floor to control control devices (PLC, drives, screens, etc.).
The control cabinet is designed to control 02 systems with standard AUTOMATIC and MANUAL operation modes. The cabinet uses single-phase, 220V, 50Hz, 40 Amp power.
The equipment system is completed as designed. The application of TK Plate® Settler, TK Collector® enables space and construction weight savings while increasing the scale of the plant’s capacity.
