Case Study: Javen 10% for Disinfecting the Water Supply System at the Long Thành Industrial Park
1. Background
The Long Thành Industrial Park (Đồng Nai) is one of the key industrial parks in the South, with a centralized water supply system with a capacity of 2,000 m³/day serving more than 40 factories within the park. The water is sourced from surface water in the Dong Nai River and undergoes sedimentation, filtration, and disinfection before being distributed to the factories.
For many years, the entity operating the water supply system used chlorine tablets (TCCA 90%) for disinfection. However, when the industrial park expanded to Phase 2, increasing water supply capacity from 1,200 to 2,000 m³/day, the old method was no longer sufficient.
2. Issues
The chlorine tablet method revealed a series of shortcomings when the scale doubled:
| Issue | Description | Impact |
|---|---|---|
| High chemical costs | TCCA 90% at 55,000–65,000 VND/kg, dosage 3–5 g/m³ | Chemical costs 330,000–390,000 VND/day |
| 100% manual operation | Workers must weigh chlorine tablets, place them in a dissolution tank, stir thoroughly, and then feed the solution into the contact tank | Requires 2 workers per shift; risk of exposure to hazardous chemicals |
| Unstable residual chlorine concentration | Manual dissolution → fluctuating solution concentration → residual chlorine in the treated water varies between high and low levels | At times, residual chlorine exceeds 1.0 mg/L (above the threshold), and at other times falls below 0.3 mg/L (failing to ensure disinfection) |
| TCCA residue | Slow-dissolving chlorine tablets tend to settle at the bottom of the tank | Pipe blockages, equipment corrosion |
| No automation integration | Cannot be connected to the SCADA system for remote control | Operation is entirely dependent on human intervention |
3. Solution
Following a site survey, Lộc Thiên Chemicals recommends switching to 10% Javen (NaOCl — Sodium Hypochlorite) in combination with an automatic dosing system.
New Process:
- 10% Javen Storage Tanks: Install two 5,000-liter composite tanks (1 operational tank + 1 standby tank) in a covered, ventilated storage shed
- Dosing Pump: A variable-frequency-driven diaphragm pump connected to the flow signal from the upstream flow meter
- Contact Tank: Javen is dosed directly into the contact tank; no intermediate dissolution is required
- Residual Chlorine Control: An online residual chlorine sensor continuously measures at the outlet of the clean water storage tank; the feedback signal controls the dosing pump to automatically adjust the dosing rate
- SCADA Integration: The entire system is integrated into the control center, enabling remote monitoring and adjustment
| Operating Parameters | TCCA Chlorine Tablets | 10% Javen |
|---|---|---|
| Dosage (g of active chlorine/m³) | 4–5 | 3–4 |
| Chemical Cost (VND/day) | 360,000 | 250,000 |
| Operating Staff | 2 people/shift (6 people/day) | 0.5 people/shift (SCADA monitoring) |
| Chemical Dosing Time | 45 minutes/batch | Continuous, automatic |
| Residual chlorine stability | ±0.5 mg/L | ±0.1 mg/L |
| Chemical exposure risk | High (manual weighing and mixing) | Low (closed system) |
Loc Thien Chemicals supplies 10% Javen from its Dong Nai warehouse, delivering three times a week via a dedicated 5,000-liter tanker truck, which pumps the solution directly into the industrial park’s storage tank—generating no packaging waste and requiring no loading/unloading labor.
4. Results
After 6 months of operation, the new system has delivered impressive results:
| Metric | Before (TCCA) | After (10% Javen) | Improvement |
|---|---|---|---|
| Chemical costs (million VND/month) | 10.8 | 7.5 | ↓ 30% |
| Labor (people/day) | 6 | 2 | ↓ 67% |
| Residual chlorine in feedwater (mg/L) | 0.2–1.2 (fluctuating) | 0.4–0.6 (stable) | 100% compliant |
| Chlorine deficiency/excess incidents | 5–7 times/month | 0 | ↓ 100% |
| Total disinfection operating costs (million VND/month) | 18.0 | 12.6 | ↓ 30% |
- Total costs reduced by 30%, saving ~65 million VND/year
- Absolutely stable water quality — no more incidents of excess or insufficient chlorine
- Fully automated operation; staff only need to monitor via the SCADA screen
- Occupational safety significantly improved — no more manual handling of hazardous chemicals
- Disinfection records are automatically stored on SCADA, facilitating routine inspections and audits
5. Lessons Learned
- 10% Javen (NaOCl) is the optimal disinfection solution for centralized water supply systems — easy to automate, 30% lower cost than chlorine tablets
- Invest in an online residual chlorine sensor + a variable-frequency dosing pump — payback in under 12 months thanks to savings on chemicals and labor
- Implementing SCADA for the disinfection system — not only saves costs but also provides a solid legal safeguard with automatically stored operational data
🔰 Do you need 10% Javen for your water supply or wastewater treatment system?
Lộc Thiên Chemicals provides 10% Javen with consistent quality, delivers in bulk tanks directly to your site, and offers support for designing dosing systems.
📞 Hotline: 0979 891 929
🏭 Warehouses: Ho Chi Minh City, Ba Ria-Vung Tau, Dong Nai, Da Nang, Can Tho, Bac Ninh