STP & ETP Complete Guide in India

1. What Is STP & ETP?

A Sewage Treatment Plant (STP) treats domestic wastewater from residential societies, hotels, hospitals and institutions. An Effluent Treatment Plant (ETP) treats industrial wastewater containing chemicals, oils and hazardous contaminants.

Both systems are legally mandated under CPCB and SPCB regulations to prevent water pollution and protect public health.

2. Difference Between STP & ETP

• STP treats biodegradable domestic sewage
• ETP treats chemically complex industrial effluent
• STP relies mainly on biological treatment
• ETP combines physico-chemical + biological processes

3. STP & ETP Technologies Used in India

Modern wastewater treatment plants use advanced, space-efficient and energy-optimized technologies.

• MBBR – Moving Bed Biofilm Reactor
• SBR – Sequencing Batch Reactor
• MBR – Membrane Bioreactor
• ASP – Activated Sludge Process

4. STP & ETP Cost in India

Cost depends on capacity, discharge norms, automation and reuse requirements.

• Small STP (10–50 KLD): ₹5–15 lakh
• Medium STP (100–500 KLD): ₹20–80 lakh
• Industrial ETP: ₹25 lakh to ₹5 crore+

5. CPCB, SPCB & NGT Rules

• Consent to Establish (CTE)
• Consent to Operate (CTO)
• Online Effluent Monitoring (OCEMS)
• Mandatory reuse or ZLD for selected sectors

6. ZLD (Zero Liquid Discharge) System

ZLD systems ensure that no wastewater is discharged outside the premises. All treated water is reused, leaving only solid waste for disposal.

7. Industry-Wise Applications

• Hospitals – infection control & reuse
• Hotels – flushing & landscaping reuse
• Industries – regulatory compliance
• Societies – groundwater protection

8. Common STP & ETP Failures

• Improper pH control
• Sludge mismanagement
• Blower and pump neglect
• Untrained operators

9. How to Choose the Right Vendor

• Regulatory experience
• AMC and O&M capability
• Lifecycle cost approach
• Proven installations

10. Why A2Z Enviro Services

A2Z Enviro Services delivers turnkey STP, ETP and ZLD solutions with focus on compliance, efficiency and long-term performance across India.