Nine Million Litres a Day: Relocate the Dyeing Cluster or Treat It in Place?
A walled-city cluster of 140 dyeing and tanning units, 60% of them employing fewer than ten workers, discharges about 9 million litres a day of untreated effluent into a drain that meets the river 14 km downstream. A city water-supply intake lies 25 km further down. The High Court has given 18 months to stop the discharge.
Two options are on the table. Option A: a common effluent treatment plant (CETP) on 4 hectares inside the city, capital cost ₹60 crore, operating cost ₹28 per kilolitre, of which the units say they can bear ₹12. Option B: a relocation estate 22 km away, plots at ₹4,500 per square metre with a 40% capital subsidy; most workers live within 3 km of the old cluster, and a round trip to the new site costs ₹70 and 90 minutes.
There is funding for one option, not both. The municipal commissioner must send a recommendation to the state within a month.
1. Explain why a cluster of individually small units produces a large pollution problem, and identify who currently bears the cost of the discharge.
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Why small units produce a large problem
- Each unit falls below the threshold of individual notice. A ten-worker dyeing unit releasing a few kilolitres a day is invisible; 140 of them produce 9 MLD.
- Treatment has scale economies. No single unit can finance a plant at efficient scale, so abatement requires a CETP - that is, collective action among 140 competing firms with no enforceable contract. This is a classic collective-action failure.
- The pollutant is a public bad. The cost is externalised downstream, so the unit's private cost of discharge is near zero and no market signal reaches it - a negative externality.
- Tenure and informality. Small units often lease premises, cannot offer collateral, and cannot finance capital works even if willing.
Who bears the cost today
- Users and the ecosystem along 14 km of drain.
- The city water intake 25 km downstream: the extra treatment cost of abstracting contaminated river water falls on the municipal utility - that is, on households, not on the tanners.
- Farmers irrigating from the drain, whose soils and yields degrade.
- The state, in eventual cleanup, litigation and public health costs.
Framing for the commissioner: the question is not whether the units are guilty, but what institutional arrangement makes abatement affordable at the scale at which it is technically efficient.
2. Compare Option A and Option B on environmental effectiveness, employment, and cost incidence.
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Option A - in-situ CETP on 4 ha
- Environment: strong. Treatment at the point of generation, no new discharge path. But 4 ha inside a walled city is scarce and the plant sits next to residents (odour, sludge handling).
- Employment: preserves the labour market completely; zero change in commuting.
- Cost incidence: ₹60 crore capital. O&M = ₹28/kl × 9 MLD ≈ ₹2.52 lakh/day ≈ ₹9.2 crore a year. Units can bear ₹12/kl ≈ ₹1.08 lakh/day ≈ ₹3.9 crore a year, so the O&M gap is about ₹5.3 crore a year - larger than the capital problem, and the usual reason CETPs fail: they get built, then are not operated.
Option B - relocation estate, 22 km out
- Environment: good space and dilution; a single large plant is feasible. But relocation within 18 months is very tight, and there is a real risk of units "relocating" on paper while continuing to operate in the city.
- Employment: 60% of units have fewer than ten workers living within 3 km. ₹70 a day is ₹18,000–20,000 a year per worker, roughly a month's wage - enough to break labour supply, and the first to be lost will be the skilled dyers.
- Cost incidence: plots at ₹4,500/m² plus plant, offset by a 40% capital subsidy; still beyond a ten-worker firm without credit. The uncounted cost is pushed onto workers as commuting time and fare.
Judgement: A wins on employment and on certainty of abatement; B wins on space. Neither is affordable as stated - B hides its cost in workers' transport, A hides its cost in O&M.
3. Recommend a package and identify the single condition without which it will fail.
Read the worked answer
Recommended package: in-situ CETP with a zoned estate, phased.
- Within six months: meter every unit's effluent (flow, pH, COD) and publish the data monthly. Without measurement nothing downstream is enforceable.
- Build the CETP on 4 ha under a design–build–operate contract, with payment linked to measured compliance, not to construction completed.
- Set the effluent charge above ₹12/kl and escalate it to ₹28/kl over five years, with a surcharge on units that exceed their consented load. Close the ₹5.3 crore annual O&M gap by tariff plus a time-bound state subsidy - a permanent subsidy means the plant stops the day the subsidy does.
- Relocate only the 25–30 largest units to the estate; keep the small units in a re-densified zoned area with common pre-treatment. Blanket relocation destroys the cluster's one real asset - a dense, skilled labour pool within 3 km.
- A transport stipend for workers of any unit that does move, so the cost of the transition is not silently loaded onto the lowest-paid.
The single condition without which it fails: a credible enforcement chain - metered discharge, published data, and the power to disconnect or seal a non-paying unit.
A CETP without metering becomes a bypassed drain within a year, and the ₹60 crore is spent for nothing. Capital is the easy part; O&M discipline is the binding constraint, and it is an institutional problem, not an engineering one.