Water quality: [biofuel] Wastewater often pollutes rivers

Eleven biofuels plants have been cited by the state Department of Natural Resources for wastewater violations that include polluting streams based on permit limits under the federal Clean Water Act, according to the Register’s analysis of state records for 34 plants in operation during six years.

Ethanol production requires purified water. When plants treat the water, their sewage discharges can include toxic salt levels and high iron levels. That kind of pollution can harm fish and cattle that drink from streams.

According to the Iowa Environmental Council, the concentrations of chloride and other suspended solids, mainly salts, coming from ethanol plants are among the highest of any industry in the state.

…

Ethanol plants are driving Iowa farmers to plant more corn and seek higher yields. More acres of corn will mean more fertilizer applications.

Biologists say the loss of grasslands and woods would mean less filtering of fertilizer runoff as it heads to water supplies.

Those factors lead to more nitrates in waterways. Nitrates are a colorless, odorless compound that forms when fertilizers break down. Nitrates also come from animal manure.

In untreated water, nitrates have been associated with “blue-baby syndrome” – in which a baby’s blood is stripped of its ability to carry oxygen – and a variety of cancers. A survey last year by the University of Iowa found 10 percent of rural water wells had nitrates at levels above the drinking water standard, but the contamination comes from a variety of sources.

Des Moines Register