Method development and application for measuring representative & potential denitrification rates during wastewater reclamation in soil treatment units
type: CreativeWork
description: Onsite wastewater systems can be designed and managed for robust wastewater treatment, reclamation and potential reuse. A typical onsite wastewater system treats wastewater utilizing a septic tank connected to a soil treatment unit. Although soil treatment units provide significant removal of many contaminants such as suspended solids, pathogens and organic content; mass loading of nitrogen remains a top concern. Previous research focused on quantifying and modeling nitrogen fate in and below soil treatment units has identified the large variability in denitrification rates as a major obstacle. A method for quantifying representative and potential rates of denitrification in soil subject to wastewater application was developed and implemented. Four columns were packed with soil classified as Seffner fine sand obtained from Central Florida. The soil had sand-silt-clay percentages of 95-1-4, respectively (% weight). This fine sand had an effective size (D10) of 0.12 mm, a uniformity coefficient of 2.3, a pH of 5 and a fraction of organic carbon ranging from 0 - 0.05 (% weight). All four soil columns were dosed two times per day at a hydraulic loading rate of 2 cm/d. Half of the columns were dosed with septic tank effluent and the other half were dosed with nitrified intermittent sand filter effluent. Effluent applied to the columns and percolate exiting the columns was characterized to facilitate a nitrogen mass balance. After 68 days of operation, two of the soil columns were deconstructed and subject to numerous denitrification rate measurements using both static core acetylene inhibition (representative rate based on actual conditions) and denitrification enzyme activity (potential rate based on optimal conditions) methodologies. Prior to application of wastewater effluent the native Seffner fine sand was subject to numerous potential denitrification rate measurements; potential denitrification rates were not detectable. After ten weeks of operation, results from t…
abstract: Onsite wastewater systems can be designed and managed for robust wastewater treatment, reclamation and potential reuse. A typical onsite wastewater system treats wastewater utilizing a septic tank connected to a soil treatment unit. Although soil treatment units provide significant removal of many contaminants such as suspended solids, pathogens and organic content; mass loading of nitrogen remains a top concern. Previous research focused on quantifying and modeling nitrogen fate in and below soil treatment units has identified the large variability in denitrification rates as a major obstacle. A method for quantifying representative and potential rates of denitrification in soil subject to wastewater application was developed and implemented. Four columns were packed with soil classified as Seffner fine sand obtained from Central Florida. The soil had sand-silt-clay percentages of 95-1-4, respectively (% weight). This fine sand had an effective size (D10) of 0.12 mm, a uniformity coefficient of 2.3, a pH of 5 and a fraction of organic carbon ranging from 0 - 0.05 (% weight). All four soil columns were dosed two times per day at a hydraulic loading rate of 2 cm/d. Half of the columns were dosed with septic tank effluent and the other half were dosed with nitrified intermittent sand filter effluent. Effluent applied to the columns and percolate exiting the columns was characterized to facilitate a nitrogen mass balance. After 68 days of operation, two of the soil columns were deconstructed and subject to numerous denitrification rate measurements using both static core acetylene inhibition (representative rate based on actual conditions) and denitrification enzyme activity (potential rate based on optimal conditions) methodologies. Prior to application of wastewater effluent the native Seffner fine sand was subject to numerous potential denitrification rate measurements; potential denitrification rates were not detectable. After ten weeks of operation, results from t…
author: Farrell, Simon
language: eng
language: English
keywords: denitrification, wastewater, treatment, soil, onsite
identifier: T 7217
date published: 2013
date modified: 2026-07-24T01:42:34Z
provider: Colorado School of Mines
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Colorado School of Mines. Arthur Lakes Library

PropertyValue
property ID: Handle
value: https://hdl.handle.net/11124/78723