How much does an ETP cost?

It depends on flow, inlet strength and the outlet required. A simple physico-chemical plant for low-strength effluent costs a fraction of a high-COD pharma ETP with anaerobic, aerobic and ZLD stages. Send your inlet analysis and flow — we give a budget range within one working day.

How much space does an ETP need?

Roughly 1–2.5 m² per KLD for a conventional plant, less for MBR or packaged units. Anaerobic and ZLD stages add area. We give a footprint with every preliminary scheme.

What are the discharge norms for industrial effluent in India?

General standards under the Environment (Protection) Rules: pH 5.5–9, BOD ≤ 30 mg/L, COD ≤ 250 mg/L, TSS ≤ 100 mg/L, oil & grease ≤ 10 mg/L, with industry-specific limits for parameters such as colour, phenol, ammonia, chromium and TDS. Your consent to operate from the State Pollution Control Board states the exact limits that apply.

Can treated effluent be reused in the plant?

Yes — after tertiary filtration and, where needed, UF and RO, treated effluent is commonly reused for cooling towers, floor washing, gardening and, in many plants, process make-up. Reuse reduces fresh-water cost and is mandatory in ZLD areas.

How long does it take to build an ETP?

A packaged skid for small capacity: 8–12 weeks. A site-built turnkey plant of a few hundred KLD: 5–8 months including civil work, followed by 4–8 weeks of biological seeding and stabilisation.

Do you take over plants built by other companies?

Yes. A takeover starts with a condition audit and a 4–8 week stabilisation period, after which we commit to outlet performance in the contract.

What does a comprehensive O&M contract cost?

It depends on plant size, technology, shifts and whether chemicals are included. We quote a fixed monthly fee after a site visit — most clients find it lower than their current manpower plus chemicals plus breakdowns.

Do you provide the compliance reports for the Pollution Control Board?

Yes — monthly reports with all test results, consumption and corrective actions, plus support for consent renewals and inspections.

Is there a performance guarantee?

In comprehensive contracts, yes — outlet parameters are guaranteed for a defined inlet envelope, with penalties and remedies written into the agreement.

Water & Wastewater Treatment Glossary — ETP, STP, RO, ZLD Terms Explained

ASP: Activated sludge process — aerobic biological treatment with suspended micro-organisms and a clarifier to return biomass.
AOP: Advanced oxidation process — ozone, Fenton, UV/H₂O₂ or electro-oxidation to break refractory organics.
BOD: Biochemical oxygen demand — oxygen consumed by micro-organisms degrading organics in 3 days at 27 °C (India) or 5 days at 20 °C; a measure of biodegradable load.
BOD/COD ratio: Indicator of biodegradability: above 0.5 readily biodegradable; below 0.2 largely refractory.
Blowdown: Water deliberately removed from a cooling tower or boiler to control dissolved solids.
CETP: Common effluent treatment plant serving a cluster of industries.
CIP: Clean-in-place — chemical cleaning of membranes or equipment without dismantling.
COD: Chemical oxygen demand — oxygen equivalent of all oxidisable matter, biodegradable or not.
Coagulation: Destabilising colloids with alum, PAC or ferric so they can flocculate and settle.
Consent to operate: Permission from the State Pollution Control Board fixing discharge limits and conditions for a unit.
CPU: Condensate polishing unit — removes trace impurities from returned steam condensate.
Cycles of concentration: Ratio of TDS in circulating cooling water to TDS in make-up water.
DAF: Dissolved air flotation — micro-bubbles lift oil, fat and light solids to the surface for removal.
Decanter: Centrifuge for dewatering sludge continuously.
DM plant: Demineralisation by cation and anion exchange resins to remove dissolved salts.
DO: Dissolved oxygen — maintained at 1.5–3 mg/L in aeration tanks.
DTRO: Disc-tube reverse osmosis — open-channel RO for high-TDS, high-fouling water such as leachate.
EDI: Electrodeionisation — continuous ion removal using resin and electric field, no regeneration chemicals.
Equalisation: Tank that averages out flow and load variation before treatment.
ETP: Effluent treatment plant for industrial wastewater.
F/M ratio: Food-to-micro-organism ratio — kg BOD per kg MLVSS per day; a key aeration design parameter.
Fine-bubble diffuser: Membrane diffuser giving small bubbles and high oxygen transfer efficiency.
Flocculation: Gentle mixing so destabilised particles grow into settleable floc, usually with polymer.
FSTP: Faecal sludge treatment plant for septage from tanks and pits.
HRT: Hydraulic retention time — tank volume divided by flow.
KLD: Kilolitres per day (m³/day).
Leachate: Liquid draining from a landfill, carrying dissolved and suspended waste constituents.
LSI: Langelier saturation index — predicts calcium carbonate scaling tendency.
MBBR: Moving bed biofilm reactor — biofilm on floating plastic carriers in an aerated tank.
MBR: Membrane bioreactor — activated sludge with submerged UF membranes replacing the clarifier.
MEE: Multiple-effect evaporator — steam-driven evaporation in stages for brine concentration.
MLSS: Mixed liquor suspended solids — biomass concentration in the aeration tank.
MVR: Mechanical vapour recompression — electrically driven evaporator using compressed vapour as heat source.
NTU: Nephelometric turbidity unit.
O&M: Operation and maintenance.
ORP: Oxidation–reduction potential — used to control biocide and oxidant dosing.
P&ID: Piping and instrumentation diagram — the master engineering drawing of a plant.
PAC: Poly aluminium chloride — a common coagulant.
Permeate: Water that passes through a membrane.
PFD: Process flow diagram.
Polyelectrolyte: Long-chain polymer flocculant, anionic, cationic or non-ionic.
Recovery: Permeate flow as a percentage of feed flow in a membrane system.
Reject / concentrate: Water retained by a membrane, carrying the removed salts.
RO: Reverse osmosis — pressure-driven membrane removal of dissolved salts.
SBR: Sequencing batch reactor — fill, react, settle and decant in one tank on a timed cycle.
SDI: Silt density index — fouling potential of RO feed water; target below 3.
Sludge age (SRT): Average time biomass stays in the system; long SRT for slowly degradable organics.
Softener: Ion-exchange unit replacing calcium and magnesium with sodium.
STP: Sewage treatment plant for domestic wastewater.
SVI: Sludge volume index — settleability of activated sludge; 80–150 mL/g is healthy.
TDS: Total dissolved solids.
TKN: Total Kjeldahl nitrogen — organic plus ammoniacal nitrogen.
TOC: Total organic carbon — used for purified water and refractory COD.
TSDF: Treatment, storage and disposal facility for hazardous waste.
TSS: Total suspended solids.
Tube settler: Inclined tube pack that increases clarifier settling area.
UASB: Upflow anaerobic sludge blanket reactor — high-rate anaerobic treatment producing biogas.
UF: Ultrafiltration — membrane removing turbidity, colloids and bacteria; not dissolved salts.
UPW: Ultrapure water — 18.2 MΩ·cm resistivity for electronics and laboratories.
WFI: Water for injection — pharmacopoeial grade with endotoxin limit.
WTP: Water treatment plant for raw water.
ZLD: Zero liquid discharge — no liquid effluent leaves the site; salts recovered as solids.

Glossary of water & wastewater terms

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