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Sewage Pollution in Keaukaha, Hawaiʻi, U.S.A. : An Area Impacted by Cesspools and Offshore Wastewater Outfall

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Title:Sewage Pollution in Keaukaha, Hawaiʻi, U.S.A. : An Area Impacted by Cesspools and Offshore Wastewater Outfall
Authors:Waiki, Shayla Marie Pualani
Contributors:Colbert, Steven (advisor)
Tropical Conservation Biology & Environmental Science (department)
Keywords:Environmental science
Sewage pollution
show 1 moreWater quality
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Date Issued:Aug 2022
Publisher:University of Hawaii at Hilo
Abstract:Sewage pollution in coastal waters is concerning for the health of coastal ecosystems and communities worldwide. Sewage enters the environments directly from sewage spills and treated effluent from sewage outfall pipes, or indirectly through groundwater discharge as treated or untreated effluent from on-site sewage disposal systems (OSDS) and injection wells. The presence of sewage pollution in coastal waters can lead to nutrient enrichment impacting coastal water quality and human exposure can also cause health problems. Keaukaha, Hawaiʻi, is an area susceptible to sewage pollution due to the presence of two sewage pollution sources: OSDS and the Hilo Wastewater Treatment Plant (HWTP) sewage outfall pipe. Conducting dye tracer tests, the use of a multi-indicator approach, and including a citizen science survey (the Pilau-meter) the goals of this study were to: 1) identify the connectivity of OSDS to nearshore waters, 2) characterize water quality from HWTP inlet to outfall, 3) compare water quality of OSDS-impacted springs to HWTP outfall plume, and 4) document the intensity of sewage and other smells encountered in Keaukaha using the Pilau-meter and indentify envrionmental factors associated with the presence of specific smells. Dye tracer tests found that sewage from OSDS reached shoreline springs within 20 h – 3 d, with faster flow rates than reported elsewhere in Hawai’i. HWTP influent samples were an order of magnitude higher in FIB concentrations compared to effluent samples, supporting the effectiveness of the wastewater treatment process. Nutrient concentrations increased from influent to pre-outfall samples, while DOC concentrations were three times lower. Shoreline stations were higher in nutrients except for NH4+ and DOC compared to the sewage plume. Sewage smells reported on the Pilau-meter were associated with HDOH advisories on two occasions. Our study confirms the effectiveness of using dye tracers test to determine the travel of OSDS contaminants to nearby shorelines, highlights the effectiveness of chlorination as a wastewater treatment mechanism for reducing FIB, and expands the field of odor science and using the sense of smell in research.
Pages/Duration:56 pages
Rights:All UHH dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Appears in Collections: TCBES Theses
Tropical Conservation Biology and Environmental Science

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