The US Environmental Protection Agency (EPA) has proposed to reissue the National Pollutant Discharge Elimination System (NPDES) permits to the Guam Waterworks Authority (GWA), for the Northern District and Agana sewage treatment plants.
As per the proposed permits, the GWA will have to upgrade the sewage treatment plants to full secondary treatment and also set levels for the wastewater quality as per the secondary treatment requirements.
The EPA suggested the new permits because the discharge limits from the two plants did not match the required ocean water quality standards for bacteria.
The presence of bacteria could pose risks for recreational activities such as swimming and fishing.
The water authority will have to comply with the effluent limitations to protect the region's beaches by controlling and reducing sewage spills.
EPA Pacific South-West regional administrator Jared Blumenfeld said the water authority will have to improve its drinking and wastewater infrastructure.
"These new permits underscore EPA's commitment to improve water quality for the protection of Guam's ocean waters," Blumenfeld added.
The Clean Water Act (CWA) mandates the municipal wastewater treatment plants to use primary and secondary treatment to maintain the quality of water.
If the primary water treatment standards are achieved by a plant, the CWA allows a small variance from the secondary treatment for marine discharges.
As per CWA guidelines, the two plants could not meet the minimum quality for primary treatment, which mandates removing 30% of the total suspended solids and biochemical oxygen demand.
A plant's primary treatment aims at removing objects such as rags, grit, sticks, stones, sand, cinders and other removable solids, while the secondary treatment removes organic matter in the wastewater by treating it with bacteria.
Image: The EPA has suggested that Guam Waterworks Authority upgrade its two sewage treatment plants to meet water quality standards. Photo: USDA.