The Superintendency of the Environment initiated sanction proceedings against Explotación de Aguas Mitrinhue Ltda., citing untreated wastewater discharges into the Biobío River from its housing project.
Sanction Proceedings and Charges at Project Inmobiliario Mitrinhue
The Superintendency of the Environment launched a formal sanction procedure against Explotación de Aguas Mitrinhue Ltda., the company operating the Proyecto Inmobiliario Mitrinhue residential complex in the commune of Coronel, Biobío Region. According to portal.sma.gob.cl, regulators formulated two serious charges against the firm following citizen complaints and a formal request from the Ministerial Regional Secretariat of Health of Biobío. The residential complex relies on a wastewater treatment plant designed to process domestic sewage from the local population. Environmental inspectors conducted site inspections in February 2023 and April 2025, uncovering severe operational failures.
Facility routes untreated sewage into Biobío River
Regulators determined that the wastewater treatment facility operated in conditions that deviated entirely from its original Environmental Qualification Resolution granted under RCA N° 19/1998. The first serious charge centers on the failure to implement and operate the approved treatment system, which should include screening sieves, a biological reactor, ultraviolet light sterilization, and sludge management. Instead, the facility routed untreated sewage directly into a rainwater drainage canal that empties into the Biobío River. Superintendency head Emanuel Ibarra stated that environmental resolution requirements remain mandatory for all project holders, noting that the infrastructure operated outside authorized parameters and dumped waste directly into the waterway.
Company fails to answer formal information requests
The second serious charge addresses a systematic failure by the company to answer formal information requests issued by the environmental agency. Regulators logged missing responses to demands sent via an inspection act in February 2023, alongside Resolution Ex. OBB N° 94/2023 and Resolution Ex. OBB N° 007/2025. This enforcement action builds on prior measures by the Biobío Health Ministerial Secretariat, which revoked the plant’s operational permit in February 2024 following independent sanitary evaluations.
Serious infractions risk facility closure or fines
Under the Organic Law of the Superintendency of the Environment, companies facing serious infractions risk severe penalties, including the revocation of their environmental qualification resolution, facility closure, or fines reaching up to 5,000 Annual Tax Units. The company holds an extended deadline of 15 business days to submit a compliance program and 22 business days to file formal defenses following official notification. The public case file remains accessible through the National Environmental Information and Inspection System via portal.sma.gob.cl.
Frequently Asked Questions About the Mitrinhue Sanction
What specific wastewater treatment components were missing at the Mitrinhue plant?
Inspectors found that the facility lacked the operation of approved screening sieves, a biological reactor, ultraviolet light sterilization, and proper sludge management infrastructure.
When did health authorities first revoke the plant’s operating permit?
The Health Ministerial Secretariat of Biobío revoked the facility’s operating permit in February 2024 after documenting widespread treatment failures.
Where does the untreated wastewater eventually flow?
Untreated sewage flowed into a rainwater drainage canal that empties directly into the Biobío River, according to environmental inspection findings.
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