Packaged ETP Operations: Step-by-Step Standard Operating Procedure (SOP)

Standard Operating Procedure (SOP) for Packaged Effluent Treatment Plants

Operating a packaged industrial Effluent Treatment Plant (ETP) requires precise execution of pre-start audits, dosing chemical calculations, startup sequences, and routine maintenance tasks. This step-by-step SOP ensures stable compliance, efficient chemical consumption, and longevity of Tigreen's microbubble Dissolved Air Flotation (DAF) systems.

1. Daily Pre-Start Audits & Checklists

Before powering up the system, the ETP operator must verify the following items:

• Feed Water Levels: Verify the wastewater level inside all raw collection and equalization tanks.
• Duplex Filters: Inspect and clean the manual Duplex Filters installed immediately after the feed pump. Always keep one filter operational and one on standby.
• Chemical Tanks: Confirm that the Caustic (pH correction), hydrochloric acid (HCl), Poly Aluminium Chloride (PAC), and anionic Polyelectrolyte tanks are sufficiently filled.
• Softener Salt Bed: Verify the salt regeneration tank for the resin filter has sufficient brine solution (typically 50 kg of salt dissolved in a 250-litre tank).

2. Chemical Dosing Calculations

Chemical consumption must be adjusted based on the raw influent flow rate read from the rotameter. Jar tests should be conducted daily using a 200 ml wastewater sample to identify optimal dosages.

Poly Aluminium Chloride (PAC) 18% Dosing

The standard optimum dosage identified during commissioning is 0.4 ml PAC per 200 ml sample, which equates to 1 Litre of PAC per 1 KL (1,000 L) of wastewater. Adjust dosing pump scale as follows:

Wastewater Flow Rate	PAC Consumption (L/hr)	Dosing Pump Action
0.5 KL/hr	0.5 L/hr	Calibrate to scale (Low)
1.0 KL/hr	1.0 L/hr	Calibrate to scale (Medium)
1.5 KL/hr (Max Capacity)	1.5 L/hr	Calibrate to scale (High)

Polyelectrolyte (Anionic) Dosing

The standard optimum dosage identified during commissioning is 0.3 ml Polyelectrolyte per 200 ml sample, which equates to 1.5 Litres of Polyelectrolyte per 1 KL (1,000 L) of wastewater. Adjust dosing pump scale as follows:

Wastewater Flow Rate	Polyelectrolyte Consumption (L/hr)	Dosing Pump Action
0.5 KL/hr	0.75 L/hr	Calibrate to scale (Low)
1.0 KL/hr	1.5 L/hr	Calibrate to scale (Medium)
1.5 KL/hr (Max Capacity)	2.25 L/hr	Calibrate to scale (High)

3. Start-Up Sequence (Do Not Reverse or Skip Steps)

1. Switch ON the raw wastewater pump along with the automated pH Controller from the main control panel.
2. Simultaneously activate the PAC and Polyelectrolyte dosing pumps.
3. Verify that the water level in the Tigreen DAF flotation tank rises to the lower edge of the skimmer blades.
4. Switch ON the Tigreen High-Pressure Recirculation Pump.
5. Check the high-pressure discharge pressure gauge. It must show between 7.5 bar and 8.0 bar. (Do not adjust the high-pressure globe valve manually; contact Tigreen Support for deviations).
6. Check the bubble injection point pressure at the bottom of the DAF tank. Maintain it between 3.0 bar and 3.5 bar by adjusting the local globe valve.
7. Switch ON the mechanical sludge skimmer.
8. Allow the system to run and stabilize for 20 to 30 minutes until a uniform sludge layer blankets the surface.

4. Regular Maintenance & Safety Schedules

Adhering to preventive maintenance prevents regulatory non-compliance and pump failures.

• Daily: Conduct a manual Jar Test before plant startup; log flow rate, pH levels, and chemical volumes.
• Twice Weekly: Gently wash the pH probe with fresh water to prevent fouling from surfactant films.
• As Required: Replenish chemical tanks, refill the salt tank (~50 kg salt), and dispose of dried sludge cake in accordance with local PCB regulations.