KLD (KLD)

KLD (Kilo Litres per Day) is the standard Indian unit for expressing liquid flow rates, equal to 1,000 litres per day or 1 cubic metre per day. KLD is used universally in environmental consent applications, SPCB discharge norms, ETP design specifications, water supply infrastructure, and sewage treatment plant capacity ratings. The unit's prevalence is driven by its convenient size — most industrial and municipal water flows in India fall in the 1–1,000 KLD range, allowing clean integer expression.

Common KLD reference points in Indian recycling and CBG operations:

• Small dry-process units (e-waste dismantling, e-waste granulation) — 0.5–5 KLD of process effluent plus sanitary
• Plastic washing lines — 5–25 KLD effluent per 1 TPD throughput, depending on contamination of feedstock
• Mid-size CBG plant — 50–200 KLD digestate liquor after solids separation, varying with feedstock TS
• Tyre pyrolysis — 10–30 KLD of cooling tower bleed, condensate, and process water
• Threshold for STP requirement — Premises generating more than 10 KLD of sewage typically require dedicated STP under SPCB norms
• Threshold for ZLD consideration — Effluent above 25–50 KLD with high TDS (above 2,100 mg/L) typically requires Zero Liquid Discharge in many states

KLD figures in SPCB consent applications drive several downstream consequences. Consent fees in many states scale with KLD; ETP capex scales roughly linearly with KLD; water cess under the now-merged GST framework was historically calculated on KLD consumed; ground water extraction permits from Central Ground Water Authority specify KLD limits.

For project design, the relevant trade-off is between water consumption and recycling. A plastic washing line consuming 20 KLD of fresh water can typically reduce to 4–6 KLD by adding clarifier-filter-RO recirculation, but the capex (₹15–35 lakh) and opex (chemicals, RO membranes, energy) must be weighed against the marginal water cost (₹40–80 per KL from tanker, ₹15–25 per KL from municipal supply). In water-scarce states (Gujarat, Rajasthan, Tamil Nadu), the SPCB increasingly mandates water recycling as a CTO condition rather than leaving it to economic choice.