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Twenty-five United Nations member states in the wider Caribbean region ratified the Cartagena Convention, which covers the marine environment of the Gulf of Mexico, the Caribbean Sea and some parts of the Atlantic Ocean. The Land-Based Sources and Activities protocol (LBS Protocol) of that convention addresses nutrient pollution from sewage discharges, agricultural runoff and other sources. Unfortunately, most Caribbean people use conventional onsite wastewater treatment systems (OWTs), especially septic systems. These systems fail to remove nitrogen effectively, posing a challenge for near shore environments. Passive biological nitrogen removal (BNR) processes have been developed for OWTs that rely on simple packed bed bioreactors, with little energy or chemical inputs and low operations and maintenance (O&M) requirements. This paper provides a case study from Florida on the partnerships and pathways for research to develop an innovative technology, Hybrid Adsorption and Biological Treatment System (HABiTS), for nitrogen reduction in OWTs. HABiTS combine ion exchange materials and BNR to remove nitrogen from septic tank effluent and buffer transient loadings. HABiTS, employs natural zeolite material (e.g. clinoptilolite) and expanded clay in the first stage to achieve both ammonium ion exchange and nitrification. The second stage of HABiTS utilizes tire chips, elemental sulphur pellets and oyster shells for adsorption of nitrate as well as sulphur oxidizing denitrification. Under transient load applications, the nitrogen in excess of the biodegradation capacity during high loading events was partially retained within the ion exchange and adsorption materials and readily available later for the microorganisms during lower loading events. Results from a bench scale bioreactor study with marine wastewater, which is relevant to where seawater is used for toilet flushing, are also presented. Pilot scale tests on the OWT of an engaged stakeholder dependent on the marine environment, would contribute to broader discussions for paradigm shifts for nutrient removal from wastewater.
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This content will become publicly available on August 1, 2026
Assessing Environmental Complexities of Decentralized Wastewater Infrastructure Using Machine Learning: A Case Study
Onsite wastewater treatment systems (OWTSs), such as septic systems, are widely used in the United States, with 16.4% of households relying on them. OWTSs process approximately 4 billion gallons of wastewater per day, yet only about half is safely treated. Identifying factors contributing to impaired functionality is crucial for developing effective management and monitoring strategies and protecting environmental and human health. This study uses a machine learning approach and a unique data set from Athens-Clarke County, Georgia, to predict OWTS failures based on environmental and system-specific variables. The three main predictors of impaired OWTS function were the number of bedrooms (25.4%), height above stream (18.6%), and system age (16.2%), with both older and younger systems prone to failure. Our findings suggest there is a need to reevaluate construction guidelines for effective tank and drainfield sizing, placement, and construction, and our findings indicate that additional training for permitters, installers, and homeowners may be beneficial. Our work demonstrates the power of using machine learning to assess OWTS function, which can better enable local governments and environment managers to identify areas in need of infrastructure and educational investment with limited data and highlights the data types that local jurisdictions should prioritize for collection.
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- Award ID(s):
- 1941555
- PAR ID:
- 10627655
- Publisher / Repository:
- American Society of Civil Engineers
- Date Published:
- Journal Name:
- Journal of Water Resources Planning and Management
- Volume:
- 151
- Issue:
- 8
- ISSN:
- 0733-9496
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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