Sioux City Journal: Big Ox Energy has ceased all operations after its permit to discharge wastewater to Sioux City's treatment plant expired Tuesday. The South Sioux City, Neb., biofuels plant had ceased its methane production activities on April 19 in order to make repairs to the plant, which has received numerous citations for environmental violations from Nebraska regulators. It had continued to pretreat wastewater from other South Sioux City industries and discharge it to Sioux City, but those operations now have stopped. The city of Sioux City will not renew Big Ox's permit until a number of issues are resolved, Assistant City Attorney Justin Vondrak said.