MPCB Effluent Discharge Standards: Maharashtra Pollution Control Board Guide

MPCB: Role and Jurisdiction

The Maharashtra Pollution Control Board (MPCB) is the statutory body established under the Water (Prevention and Control of Pollution) Act, 1974, responsible for regulating industrial effluent discharge across Maharashtra. MPCB operates under the dual mandate of CPCB (which sets national standards) and the Maharashtra state government, implementing and in many cases strengthening CPCB's minimum standards for Maharashtra-specific industrial concentrations.

Maharashtra's industrial landscape — spanning chemicals and pharmaceuticals (Pune, Aurangabad, Navi Mumbai), textiles (Bhiwandi, Ichalkaranji, Solapur), sugar and distilleries (Kolhapur, Nashik, Marathwada), food processing (Pune, Mumbai), and a growing IT/ITES sector — creates one of the most complex regulatory environments for industrial water management in India. MPCB enforces standards through a network of regional offices in Mumbai, Pune, Nashik, Aurangabad, Nagpur, Amravati, and Konkan divisions.

MPCB's authority covers: issuing Consent to Establish (CTE) for new projects; Consent to Operate (CTO) for operating industries; authorisation for hazardous waste handling under Hazardous and Other Waste Rules, 2016; enforcement actions including closure directions under Section 33A of the Water Act; environmental compensation orders; and criminal prosecution under the Environment Protection Act, 1986. MPCB also oversees compliance with CPCB's OCEMS (Online Continuous Effluent Monitoring System) requirements for red-category units.

Effluent Discharge Standards by Receiving Body

MPCB effluent standards are set differently depending on where the treated effluent is discharged. The three receiving environments — inland surface waters (rivers, streams, lakes), public sewers (municipal drainage systems), and land (for irrigation or controlled land application) — have significantly different standards reflecting their different assimilative capacities.

Discharge to inland surface waters (Schedule VI — Class I rivers, tributaries): BOD <30 mg/L; COD <250 mg/L; TSS <100 mg/L; pH 6.5–9.0; oil and grease <10 mg/L; TDS <2,100 mg/L; total nitrogen <100 mg/L; total phosphorus <5 mg/L; temperature at the point of discharge ≤5°C above ambient water temperature. For discharge to Class A rivers (bathing ghats, drinking water intake upstream): BOD <10 mg/L may be specified in the consent condition.

Discharge to public sewer (municipal drainage network): BOD <350 mg/L; COD <500 mg/L; TSS <600 mg/L; pH 5.5–9.0; oil and grease <20 mg/L; temperature <45°C. These less stringent standards reflect that municipal STPs provide secondary treatment of the combined municipal + industrial flow before the final discharge to water bodies. However, MPCB has been progressively tightening sewer standards in urban areas where municipal STPs are overloaded.

Discharge to land (irrigation/controlled land application): pH 5.5–9.0; BOD <100 mg/L; EC <2.25 dS/m; SAR (sodium adsorption ratio) <26; boron <2 mg/L. This is most relevant for industries with large land areas available — sugar mills, distilleries, and food processing units in rural Maharashtra — where treated effluent is used for irrigation under a controlled land application scheme approved by MPCB.

Industry-Specific MPCB Standards

Beyond the general standards, MPCB applies industry-specific discharge standards for high-impact sectors. These are drawn from CPCB's industry-specific Schedule I standards but may be strengthened through individual consent conditions:

• Textile dyeing and processing: BOD <30 mg/L; COD <250 mg/L; TDS <2,100 mg/L; colour 100 ADMI units; sulphide <2 mg/L; chromium (total) <2 mg/L. For units in Bhiwandi, Ichalkaranji, and other notified textile zones: ZLD is mandated (see below).
• Pharmaceutical manufacturing: BOD <30 mg/L; COD <250 mg/L; TSS <100 mg/L; pH 6.5–9.0; bioassay (96-hr LC₅₀) >100% — meaning the treated effluent must not cause mortality in more than 50% of test fish at 100% concentration. This bioassay requirement is Maharashtra-specific and stricter than most other states.
• Dairy processing: BOD <30 mg/L; COD <250 mg/L; TSS <100 mg/L; oil and grease <10 mg/L; pH 6.5–9.0. For large dairy plants (>50,000 L/day milk intake), OCEMS is required.
• Slaughterhouse and meat processing: BOD <30 mg/L; COD <250 mg/L; TSS <100 mg/L; oil and grease <10 mg/L; pH 6.5–9.0; E. coli <30 MPN/100 mL. Mandatory UV or chlorination disinfection before discharge.
• Sugar mills: BOD <30 mg/L; COD <250 mg/L; TSS <100 mg/L; colour <200 hazen units; sulphate as SO₄ <1,000 mg/L. Molasses-based distillery units co-located with sugar mills face separate ZLD directions for spent wash.

MPCB ZLD Directions for Maharashtra Industries

MPCB has issued Zero Liquid Discharge directions for specific industry sectors and geographic zones, building on CPCB's national ZLD framework. Current MPCB ZLD mandates:

Textile dyeing and processing: Units in Bhiwandi (Thane district), Ichalkaranji (Kolhapur), and Solapur dyeing clusters have received MPCB ZLD directions. These units must demonstrate zero liquid discharge at their premises boundaries — no treated or untreated effluent may leave the premises as liquid. Compliance pathway: biological pre-treatment + RO + MEE/MVR evaporation + ATFD crystallisation.

Pharmaceutical manufacturing: Units in MIDC areas near environmentally sensitive zones (near rivers or ecologically sensitive areas) have received ZLD directions from MPCB. The Aurangabad MIDC pharmaceutical cluster and portions of the Navi Mumbai pharmaceutical zone have formal ZLD requirements.

Distilleries: Following CPCB's national direction, all molasses-based distillery units in Maharashtra are required to achieve ZLD for spent wash — through evaporation + composting, incineration, or membrane ZLD routes. Compliance status is monitored through quarterly MPCB inspections.

Critically Polluted Areas (CPAs): MPCB applies heightened monitoring and compliance requirements to industries in CPCB-identified CPAs. Maharashtra CPAs include Tarapur, Chandrapur, Ambarnath, Dombivli, and Sinnar industrial areas. Industries in these zones may receive individual ZLD notices based on CEPI (Comprehensive Environmental Pollution Index) scores.

Consent to Operate: Application, Renewal, and Documents

The Consent to Operate (CTO) is the operating licence that MPCB issues to all industries covered by the Water and Air Pollution Control Acts. Operating without a valid CTO is a criminal offence. The application, approval, and renewal process:

New industries: Must first obtain Consent to Establish (CTE) before construction begins. CTE is valid for the project development period (typically 3–5 years). After construction and ETP commissioning, the industry applies for CTO before commencing production. CTO for a new red-category unit requires: ETP performance test report (from an NABL-accredited laboratory); process flow diagram; site visit by MPCB technical officer; hazardous waste authorisation (if applicable); OCEMS installation certificate.

Renewal of existing CTO: Red-category industries must renew CTO annually; orange-category every 3 years; green-category every 5 years. Renewal application submitted 4 months before expiry. Required documents: last 12 months of effluent analysis reports (minimum quarterly from NABL lab); OCEMS data summary; ETP operation log book; list of any MPCB notices received and action taken; updated plant layout; hazardous waste manifest copies; water audit data; third-party ETP audit report (mandatory for large red-category units).

Online portal: MPCB processes CTO applications through the MPCB online portal (mpcb.gov.in). All documents must be uploaded digitally; physical submission is no longer accepted for most applications. Processing time: 30–60 days for online applications that are complete and where inspection confirms compliance.

OCEMS Requirements for Red-Category Units

MPCB mandates installation of Online Continuous Effluent Monitoring Systems (OCEMS) for all red-category industries as per CPCB guidelines. OCEMS parameters monitored at the ETP outlet: pH (continuous); total dissolved solids / conductivity (continuous); chemical oxygen demand (COD) — either continuous online analyser or UV-Vis proxy; flow rate (electromagnetic flow meter); temperature. For specific industries: colour (ADMI) for textile units; total nitrogen for dairy and food processing above threshold capacity.

OCEMS data must be transmitted in real-time to MPCB's central monitoring server and to CPCB's national monitoring portal. Data gaps exceeding 2 hours trigger automatic alerts in the MPCB monitoring system. Industries must maintain OCEMS sensor calibration records, with third-party calibration verification quarterly. The OCEMS data stream is tamper-evident — any interruption or anomalous data pattern is automatically flagged and may trigger an inspection.

Industries installing OCEMS for the first time must submit the installation plan to MPCB for approval before commissioning. Approved makes/models of analysers are specified in MPCB's OCEMS standard operating procedure. Data logging hardware and communication modems must meet MPCB's cybersecurity and data integrity specifications. The industry bears the full capital and operating cost of OCEMS installation and maintenance.

Enforcement, Penalties, and Closure Directions

MPCB's enforcement escalation follows a graduated sequence from advisory through criminal prosecution. The typical escalation for ETP non-compliance:

• Level 1 — Show Cause Notice (SCN): Issued when effluent analysis reports show non-compliance or during inspection. The industry must respond within 15–30 days with a compliance corrective action plan and timeline.
• Level 2 — Environmental Compensation (EC): MPCB levies EC at rates prescribed by NGT — ₹10,000/day for small industries, up to ₹5,00,000/day for large red-category units. EC is applied for the entire period of non-compliance, not just the inspection date.
• Level 3 — Direction under Section 33A: MPCB can direct the industry to close specific processes or the entire plant if compliance is not achieved within a specified timeline. Section 33A directions are passed by the MPCB Member Secretary and are effective immediately.
• Level 4 — Criminal prosecution: Under Section 43 of the Water Act, first conviction carries imprisonment of 1.5–6 years and fine ₹10,000–₹50,000; subsequent conviction is imprisonment of 2–7 years. Under the Environment Protection Act, imprisonment up to 5 years and fine up to ₹1 lakh per day of continuing violation.

NGT (National Green Tribunal) has been an additional enforcement channel — citizen complaints or MPCB's own referrals to NGT have resulted in orders requiring remediation of polluted water bodies at the polluting industry's cost, with MPCB-appointed monitoring committees tracking compliance.

The practical advice for industries: maintain a compliance calendar with CTO renewal dates, OCEMS calibration schedules, and effluent sampling dates. Keep the ETP operation log updated daily. Respond to SCNs within the stated timeline — delayed responses are treated as non-responsiveness and accelerate the enforcement escalation.