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Low flow water quality in rivers; septic tank systems and high-resolution phosphorus signals

Biomedical Sciences Research Institute Computer Science Research Institute Environmental Sciences Research Institute Nanotechnology & Advanced Materials Research Institute

Macintosh, Katrina, Jordan, Philip, Cassidy, R., Arnscheidt, Joerg and Ward, C. (2011) Low flow water quality in rivers; septic tank systems and high-resolution phosphorus signals. SCIENCE OF THE TOTAL ENVIRONMENT, 412 . pp. 58-65. [Journal article]

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DOI: 10.1016/j.scitotenv.2011.10.012

Abstract

Rural point sources of phosphorus (P), including septic tank systems, provide a small part of the overall phosphorus budget to surface waters in agricultural catchments but can have a disproportionate impact on the low flow P concentration of receiving rivers. This has particular importance as the discharges are approximately constant into receiving waters and these have restricted dilution capacity during ecologically sensitive summer periods. In this study, a number of identified high impact septic systems were replaced with modem sequential batch reactors in three rural catchments during a monitoring period of 4 years. Sub-hourly P monitoring was conducted using bankside-analysers. Results show that strategic replacement of defective septic tank systems with modern systems and polishing filters decreased the low flow P concentration of one catchment stream by 0.032 mg TP L(-1) (0.018 mg TRP L(-1)) over the 4 years. However two of the catchment mitigation efforts were offset by continued new-builds that increased the density of septic systems from 3.4 km(-2) to 4.6 km(-2) and 13.8 km(-2) to 172 km(-2) and subsequently increased low flow P concentrations. Future considerations for septic system mitigation should include catchment carrying capacity as well as technology changes. (C) 2011 Elsevier B.V. All rights reserved.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences
Faculty of Life and Health Sciences > School of Environmental Sciences
Research Institutes and Groups:Environmental Sciences Research Institute
Environmental Sciences Research Institute > Freshwater Sciences
ID Code:21303
Deposited By:Professor Philip Jordan
Deposited On:22 Apr 2012 12:15
Last Modified:22 Apr 2012 12:15

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