Quantifying Total Phosphorus and Heavy Metals in Residential Septage

Septic systems are used for wastewater treatment in rural areas. Septic tanks promote stratification of wastewater into solid (sludge and scum) and liquid layers. Pollutant concentrations in the layers of residential septic tanks may be highly variable, and thus septage pumped from tanks with different layer thicknesses may also be variable. The goal of this study was to quantify the total phosphorus (TP) and heavy metal concentrations and masses of residential septage. The solid and liquid layer thicknesses were measured in 37 septic tanks. Samples were collected from each layer for pollutant concentration analysis. The median TP concentration (10.6 mg L−1) was greatest in the sludge layer, followed by the scum (5.3 mg L−1) and liquid (1.8 mg L−1) layers. Concentrations of heavy metals were highly variable for each layer type. The masses of the TP, cadmium, copper, lead, nickel, and zinc contained median (range) values of 19.4 g (0.9–1041 g), <0.01 g (<0.01–1.99 g), 1.3 g (0.1–520 g), 1.8 g (<0.01–44.2 g), 1.3 g (<0.01–4.3 g), and 13.8 g (0.3–788 g), respectively. Since septage is typically applied on land as a soil amendment for crop growth, it is important that representative composite samples are collected to prevent excess buildup of TP and metals, which may harm yields or environmental health

Evaluation of Fecal Indicator Bacteria Concentrations in Watersheds Served by Varying Densities of Onsite Wastewater Systems in the North Carolina Piedmont

Onsite wastewater systems (OWS) are commonly used in North Carolina for wastewater treatment. Wastewater contains elevated concentrations of pathogens. If OWS do not efficiently treat wastewater then high concentrations of microorganisms may be contributed to water resources. The fecal indicator bacteria (FIB) Escherichia (E.) coli and enterococci are often used to assess the environmental health risks associated with microbial contamination. The goal of this study was to gain a better understanding of the influence that onsite system density have on FIB concentrations in piedmont streams. The studied streams included segments of Lick Creek, Laurel Creek, and Little Lick Creek and all are tributaries of Falls Lake, a water supply and recreation source for central North Carolina. Stream sampling occurred approximately monthly between January 2015 to December 2016 at 13 sample locations in the watersheds. Monitoring included the analyses of stream samples for E. coli and enterococci and, physical and chemical parameters including: pH, temperature, dissolved oxygen, oxygen-reduction potential, specific conductivity, stream discharge, and turbidity. The geometric mean of E. coli and enterococci concentrations in streams were typically elevated in smaller watersheds ( 500 ha) with lower densities of OWS. These data suggest that the density of OWS and watershed size may influence FIB concentrations in streams

Evaluation of Fecal Indicator Bacteria Concentrations in Watersheds Served by Varying Densities of Onsite Wastewater Systems in the North Carolina Piedmont

Onsite wastewater systems (OWS) are commonly used in North Carolina for wastewater treatment. Wastewater contains elevated concentrations of pathogens. If OWS do not efficiently treat wastewater then high concentrations of microorganisms may be contributed to water resources. The fecal indicator bacteria (FIB) Escherichia (E.) coli and enterococci are often used to assess the environmental health risks associated with microbial contamination. The goal of this study was to gain a better understanding of the influence that onsite system density have on FIB concentrations in piedmont streams. The studied streams included segments of Lick Creek , Laurel Creek , and Little Lick Creek and all are tributaries of Falls Lake , a water supply and recreation source for central North Carolina. Stream sampling occurred approximately monthly between January 2015 to December 2016 at 13 sample locations in the watersheds. Monitoring included the analyses of stream samples for E. coli and enterococci and , physical and chemical parameters including: pH , temperature , dissolved oxygen , oxygen-reduction potential , specific conductivity , stream discharge , and turbidity. The geometric mean of E. coli and enterococci concentrations in streams were typically elevated in smaller watersheds ( 500 ha) with lower densities of OWS. These data suggest that the density of OWS and watershed size may influence FIB concentrations in streams

Geochemistry of Flood Waters from the Tar River, North Carolina Associated with Hurricane Matthew

Hurricane Matthew caused flooding in Eastern North Carolina that was categorized as a one in 500-year frequency event. Matthew was the second such event in less than 20 years, following Hurricane Floyd in 1999. The frequency of intense storms is projected to increase for many coastal areas, including North Carolina, because of climate change. The goal of this study was to gain a better insight into the geochemistry of flood waters associated with major flood events. Water samples (n = 22) from the Tar River in Greenville, North Carolina were collected over a two-week period after Matthew moved across the state. Results show that total Kjeldahl nitrogen, dissolved organic carbon, phosphate, and Escherichia coli concentrations and exports were significantly (p &lt; 0.05) higher when the river was above flood stage relative to below. Isotopic analyses of &delta;15N and &delta;18O in NO3 in flood waters suggest that wastewater, possibly from sanitary sewer and confined animal feeding operation overflows, was the major source of nitrate associated with flood waters. Regulatory efforts to reduce nutrient loading to coastal waters may be complicated by contributions associated with intense storm events, given that such storms are becoming more frequent

Fecal Indicator Bacteria Transport from Watersheds with Differing Wastewater Technologies and Septic System Densities

Wastewater contains elevated concentrations of fecal indicator bacteria (FIB). The type of wastewater treatment technology and septic system density may influence the FIB concentration and exports at the watershed scale. The goal of this study was to gain a better understanding of FIB concentrations and exports from watersheds served by conventional septic (CS) systems, sand filter (SF) septic systems, and a municipal sewer (SEW) system. Seven watersheds (3 CS, 3 SF, and 1 SEW) were monitored to quantify FIB concentration and export monthly from April 2015 to March 2016. The type of wastewater treatment did not yield significant differences in FIB concentration or exports when pooling watersheds using similar wastewater treatment. Watersheds with the highest septic densities (approximately 0.4 systems ha&minus;1) contained greater FIB concentrations and exports than watersheds with the lowest (approximately 0.1&ndash;0.2 systems ha&minus;1), but only FIB concentrations significantly differed. These findings suggest that when the septic system density exceeds 0.4 systems ha&minus;1, water quality degradation from septic leachate may be observable at the watershed scale, especially in watersheds dominated by residential development. More research is recommended to determine if this density threshold is similar for other water pollutants and/or in watersheds with differing hydrogeological, land use, and wastewater characteristics