Distillery spent wash, a February fish kill, and 24 villages on the river
A sugar factory in a drought-prone taluka runs a 45 kilolitre-per-day distillery alongside a 2,500 tonne-per-day crushing plant. Its consent to operate from the Maharashtra Pollution Control Board is for 45 kLPD, but through the 110-day season the distillery runs at about 60 kLPD. Spent wash is held in a lined lagoon designed for 30 days and then spread as fertigation on 60 hectares of leased farmland. In February a first-order stream 1 km below the factory shows BOD 48 mg/L and dissolved oxygen 1.8 mg/L, against 3 mg/L and 6.4 mg/L upstream. A fish kill is reported 8 km downstream. Twenty-four villages draw drinking water from the river and from wells within 300 m of it. In April the stream flow falls to about 0.2 cubic metres per second. The factory says the waste is organic, that the land application is a fertiliser practice, and that 400 cane farmers and 120 workers depend on it.
1. Separate the possible causes of the river data and describe how you would identify the dominant one.
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There are at least four candidate causes and they call for different remedies, so the first job is diagnosis, not blame.
(a) Capacity exceedance: 60 kLPD against a consented 45 kLPD means roughly a third more spent wash than the lagoon, the land area and the dilution were designed for. (b) Practice failure: land spreading is only defensible with the prescribed composting period and dilution, applied at agronomic rates and not in the monsoon; a lagoon with no freeboard in February suggests it has been drawn down by overflow, not by planned use. (c) A direct bypass, which is a different offence. (d) Low-flow concentration: at 0.2 cubic metres per second there is almost no dilution, so even a compliant discharge produces a visible sag.
How to separate them: run a load calculation. Sixty kLPD of spent wash at a COD of roughly 80,000-100,000 mg/L is tonnes of oxygen demand per day going into a stream carrying about 17,000 cubic metres a day. That magnitude points to a point source, not field runoff. Then sample longitudinally above, at and below the outfall and below the spreading fields; install piezometers in the spreading area and test groundwater COD, chloride and nitrate; check lagoon freeboard and records; compare the DO sag position with the discharge point. A sag that starts at the outfall and recovers downstream is a point source. A broad, diffuse sag tracking the fields after rain is the land application.
2. The factory argues that closure costs 520 livelihoods. How would you weigh that argument, and what would an enforceable remediation order contain?
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The livelihoods point is real but it is not a legal defence. Consent conditions under the Water Act and the EPA are not traded against employment, and accepting the argument would mean any employer could discharge by hiring enough people. It is also a weak factual claim: 120 workers are directly at risk, while the 24 villages carry the drinking-water risk, and a fish kill and contaminated wells are themselves livelihood losses for fishers and dairy owners.
An enforceable order would run in sequence. Immediate: stop land application until the monsoon risk and the agronomic rate are settled, restore lagoon freeboard, and cap throughput at the consented 45 kLPD or require a fresh consent with a proper impact assessment for 60. Short term: alternate drinking water to affected villages at the factory's cost, a health survey, compensation for the fish kill on polluter-pays lines, and groundwater testing in the spreading area. Medium term: a treatment train suited to spent wash - biomethanation, evaporation or reverse osmosis with a defined reject management route - and composting with the prescribed dilution and curing period, applied to a land area sized to the volume, with third-party audit reported to the Board.
The jobs issue belongs to the state, not to the consent: a transition plan, not a discharge licence.
3. What monitoring would show whether the fertigation is genuinely a fertiliser practice rather than a disposal route?
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The test is whether application is set by crop nutrient demand and soil capacity, or by the volume of waste arriving.
Three checks. First, a nutrient balance: spent wash is heavily loaded with potassium and organic matter, so compare the potassium and nitrogen applied per hectare against what the crop removes, and against the 60 hectares available at the consented volume. If the volume implies application rates several times the crop requirement, it is disposal with a fertiliser label. Second, soil monitoring: electrical conductivity, sodium adsorption ratio, pH, potassium and organic carbon in treated and untreated plots, sampled annually, to show whether salts are accumulating rather than being taken up. Third, groundwater: a piezometer network down-gradient of the spreading area tested for COD, nitrate, chloride and potassium, with the same tests on an up-gradient control well, because the signature of spent wash in groundwater is unmistakable.
Add administrative evidence: application dates against rainfall records, lagoon levels against inflow volumes, and weighbridge or tanker logs for wash transported off site. If the lagoon balances only when spreading happens in the rain, the practice is disposal and the order should say so.