Compact ETP Plant
Pre-engineered, modular effluent treatment plants from 10 KLD to 500 KLD — compact above-ground systems using MBBR technology for fast installation, minimal civil work, small footprint, and CPCB-compliant BOD/COD treatment for small and medium industrial facilities across India
Overview
About Compact ETP Plant
For small and medium industrial facilities — food processing units, pharmaceutical manufacturers, FMCG plants, hotels, and commercial complexes — a full civil-constructed conventional ETP is often disproportionately expensive and time-consuming relative to the effluent volumes generated. Compact and packaged ETP systems offer a faster, lower-capital, and lower-footprint alternative that delivers the same treatment performance and CPCB compliance as conventional ETP infrastructure.
Spans Envirotech's compact ETP range uses MBBR (Moving Bed Biofilm Reactor) technology as the biological treatment core — a process that achieves 3–5 times higher volumetric treatment rate compared to conventional extended aeration, allowing significantly smaller reactor tanks for the same organic load removal. The biological reactors are supplied as prefabricated above-ground tanks (FRP, polypropylene, or stainless steel) on structural steel frames, pre-piped and pre-wired in our workshop for rapid on-site assembly. Civil work is limited to a concrete equipment pad and connections to inlet and outlet drains.
Compact ETPs are available in standardised configurations from 10 KLD to 200 KLD, and in custom configurations up to 500 KLD. They are designed for full CPCB/SPCB compliance — meeting BOD ≤30 mg/L and COD ≤250 mg/L discharge standards from typical industrial effluent — and include integrated instrumentation, aeration blowers, dosing systems, and sludge handling provisions. PLC-based automation is standard on systems above 50 KLD, with remote monitoring capability available.
The compact ETP market in India has grown significantly as state PCBs have intensified enforcement against small and medium industrial units that previously operated without proper ETPs. The combination of lower capital cost, faster deployment, and minimal civil work makes compact systems the preferred choice for manufacturers who need to achieve CPCB compliance quickly without major construction projects. At the same time, the modular nature of compact systems means they can be relocated or expanded as production requirements change — offering operational flexibility that conventional civil ETPs cannot match.
Process
Compact ETP — Process Train
Primary Screening and Collection
Industrial effluent passes through a bar screen or rotary drum screen to remove coarse solids, rags, and large particles. Screened effluent collects in the equalisation tank — a critical buffer that homogenises the highly variable effluent flow and quality from shift-based industrial operations. Equalisation tank provides 6–10 hours hydraulic retention and is equipped with a submerged aeration system to prevent septicity and maintain suspended solids. Equalisaton tank sizing is typically in civil concrete — the one element of most compact ETPs that remains underground.
Primary Treatment (DAF or Chemical Dosing)
For effluent with significant FOG (food, FMCG, dairy, meat): A compact DAF unit removes fats, oils, greases, and colloidal organics using pressurised micro-bubble flotation with coagulant/polyelectrolyte dosing. DAF units for compact ETPs are available in packaged above-ground configuration from 2 m³/hr to 25 m³/hr. For lower-FOG effluent (pharmaceutical, chemical, FMCG with low cooking waste): Coagulation-flocculation tank with dosing pumps and tube settler clarification handles primary physio-chemical treatment in a compact above-ground package.
MBBR Biological Treatment
The heart of the compact ETP — MBBR reactors in prefabricated above-ground tanks treat dissolved organics using aerobic biofilm attached to plastic MBBR carriers (30–60% fill ratio). MBBR achieves 85–95% BOD removal in 4–8 hours HRT — compared to 12–24 hours for conventional activated sludge — enabling a 3–5x reduction in reactor volume. MBBR blowers (rotary lobe or turbo) maintain dissolved oxygen at 2–4 mg/L. No sludge recycle required — unlike activated sludge, MBBR does not require return sludge management, simplifying operation.
Secondary Clarification
Biological effluent from MBBR flows to a secondary clarifier — a compact tube settler or lamella clarifier — that separates biological sludge from clarified treated water. Tube settlers and lamella plates provide 3–5x higher settling capacity per m² of plan area versus conventional radial clarifiers, enabling compact, above-ground clarifier configurations. Settled sludge is returned to the MBBR reactor or forwarded to the sludge thickener.
Polishing and Disinfection
Clarified effluent passes through a pressure sand filter (PSF) and activated carbon filter (ACF) for turbidity and odour removal. UV disinfection or chlorine dosing achieves pathogen reduction as required by SPCB discharge conditions. Final treated effluent meets CPCB standards: BOD ≤30 mg/L, COD ≤250 mg/L, TSS ≤100 mg/L, pH 6.5–8.5. Optional tertiary treatment with RO membranes for water reuse applications.
Sludge Dewatering
Biological sludge from the secondary clarifier is thickened in a sludge thickener tank and dewatered using a compact volute screw press — a fully automated, enclosed dewatering unit that requires minimal operator attention. Dewatered sludge cake at 18–22% dry solids is collected in a sludge bag and disposed of as per SPCB consent conditions (non-hazardous compostable waste for food/FMCG industry sludge). Filtrate from dewatering is returned to the equalisation tank.
Benefits
Key Advantages
- 30–60% smaller footprint than equivalent conventional civil ETP
- 3–5 month faster installation vs conventional civil construction
- Prefabricated above-ground tanks — minimal civil work, only equipment pad required
- Relocatable and expandable — modules can be moved or added as production grows
- MBBR biological core is robust against variable industrial loads — no sludge bulking risk
- Available 10–500 KLD in standardised and custom configurations
- PLC automation with remote monitoring — minimal operator skill required
- CPCB/SPCB compliant — BOD ≤30 mg/L, COD ≤250 mg/L from food, FMCG, pharma effluent
- Lower capital cost per KLD than conventional civil ETP for small and medium flows
- Factory tested before dispatch — faster site commissioning and biological startup
Applications
Industries & Use Cases
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