<p> Recirculating Sand Filters (RSFs) provide a compact method of secondary treatment to septic systems and lagoons, are relatively easy to operate and require little maintenance. Together, these characteristics render RSFs particularly appropriate for small communities and municipalities, as they offer a number of economic and operational advantages over conventional technologies. A preliminary study investigating RSF effluent quality, conducted jointly by McMaster University, the Great Lakes Sustainability Fund (GLSF) and the Ontario Ministry of the Environment (MOE) in 1999-2001, conducted pilot-scale experiments and demonstrated that municipal sewage can be successfully treated year-round by RSFs. The results of the preliminary study recommended that further work be conducted to investigate the selection of media size, dosing frequency, recycle ratio, and hydraulic loading rate. </p> <p> The primary objective of this study was to develop design and operating conditions under Ontario climatic conditions with respect to media size, dosing frequency, recycle ratio and hydraulic loading rate by conducting further pilot-scale studies. Three pilot-scale RSFs, operating in parallel, were loaded intermittently with septic tank effluent to evaluate the above mentioned operating parameters on the removal of total suspended solids (TSS), 5-day carbonaceous biochemical oxygen demand (cBOD5), total ammonia-nitrogen (TAN) and total nitrogen (TN). The addition of alum was also implemented to evaluate the removal of total phosphorus (TP). The effluent objectives for this study were based on the MOE general secondary treatment level requirements of monthly averages based on a minimum of four weekly samples. The four-phase experimental program began in April, 2004 and ended in June, 2005. Three media sizes were investigated, with d10 of 2.6, 5 and 7.7 ·mm. The applied hydraulic loading rates were 0.2 and 0.4 rnlday. Dosing frequencies of 24 and 48 times/day were observed. Recycle ratios of 300% and 500% were also evaluated. </p> <p> It was found that the RSF operating with 2.6 mm media, 500% recycle ratio and 24 times/day dosing frequency under a hydraulic loading rate of 0.2 rnlday produced the best quality effluent, and achieved the effluent objectives required by the MOE. These operating criteria, however, must still be investigated under cold weather conditions to ensure acceptable year-round performance in Ontario. With proper addition of alum, the TP effluent objective was achieved under the optimum operating conditions. </p> / Thesis / Master of Applied Science (MASc)

The compatibility of home water softeners and septic tanks is of concern for the on-site wastewater treatment community. Research has shown that high sodium levels in activated sludge plants can lead to deflocculation and poor effluent quality. Therefore, it is logical to assume that high sodium levels that result from the exchange of calcium and magnesium for sodium in home softeners could give rise to poor effluent quality from septic tanks, leading to shortened lives of drain fields. Additionally, the release of regeneration discharges to the septic tank might further damage performance. This study was undertaken to investigate the effect home ion-exchange softeners have on septic tank performance. A column study was set up and varying levels of sodium were added to wastewater influent and these were fed to columns that contained solids collected from operating septic tanks. In addition, slug influent solutions, which mimic regeneration flow, with varying amounts of excess sodium were investigated. To reinforce the lab column experiments, data were obtained from private septic tanks to determine the effluent quality from septic tanks both diverting and receiving the regeneration flow. Also utilized were graduated cylinder experiments, where the effect of sodium on grease flocculation was determined, and batch anaerobic digestion studies, which determined the effect sodium has on the production of gases and the degradation of solids. The study showed that the addition of sodium to septic tanks is likely to impact the effluent quality of sewage discharged from a septic tank to a drain field. The common way of measuring ion concentrations for comparison in this study was to obtain the monovalent to divalent ratio (M/D Ratio). This is simply the concentration of the sodium ions in solution divided by the concentrations of magnesium and calcium, on an equivalent weight basis (all other monovalent and divalent ions were negligible). Slug solutions of high levels of salts (Septic Tank Effluent M/D = 11), mimicking regeneration wastes from water softeners with an inefficient regeneration cycle, increased the effluent solids, COD and BOD. However, if the regeneration wastes contained the same amount of calcium and magnesium, but a smaller amount of sodium (Septic Tank Effluent M/D = 5), the negative effect on these effluent characteristics was greatly lessened. In an optimum case with a regeneration solution containing a minimal amount of excess sodium (Septic Tank Effluent M/D = 3), the effluent characteristics were often actually more favorable than in similar situations where the regeneration wastes were diverted (Septic Tank Effluent M/D = 2). The case studies reinforced these data, showing that sodium concentrations correlated with an increased discharge of solids to the drain field. The studies on grease flocculation as well as anaerobic digestion suggest that these processes are not affected by the sodium level. Overall, it appears that the use of home softeners with septic tanks may have an effect on solids discharge to the drain field and the level of impact will depend on the level of hardness in the water, whether the regeneration waste is discharged to the septic tank, and the amount of excess sodium present in regeneration wastes. / Master of Science

When designed, installed, and maintained properly, septic systems provide a cost-effective and environmentally-sound method to treat domestic wastewater. However, poor installation, unsuitable site conditions, and infrequent maintenance can lead to system failure and the discharge of partially-treated effluent to local waterways. As many as 1%, or 4,000 systems, fail each year in the Atlanta area. Therefore, the purpose of this paper is to evaluate what social and physical factors are significant to the location of on-site sewage management system failures in Cherokee County, Georgia. A regression analysis of the septic system failure rate, which was estimated with repair permit records from the local Board of Health, with Census demographics, soil, and septic system information found that the percent of soils in the “A” hydrologic group, unemployment rate, percent African-American population, population density, household size, percent of homes built between 1980 and 1989, percent built between 1970 and 1979, percent built between 1940 and 1949, and the average lot size of the parcels issued a repair permit were statistically-significant (p < 0.05) indicators of the failure rate at the Census block group level. The inclusion of socioeconomic, environmental, and physical characteristics suggests that the most effective response to reduce failures will incorporate actions to address these significant elements collectively. Despite restrictions on the ability of the Georgia Department of Public Health to regulate maintenance, many policy options are available to proactively identify areas with the greatest likelihood of failure and reduce the incidence of failure in those areas. Greater collaboration between stakeholders, including the county Board of Health and utility providers, improved record-keeping, and education and incentive programs provide the best opportunities to improve the management of septic systems in local jurisdictions.

Residential septic systems provide reliable wastewater treatment for over 26 million homes and facilities in the United States, and many more worldwide. When properly maintained, these systems are reliable, low-cost, and long-term treatments for residential wastewater. When neglected, septic systems can fail and lead to health concerns and ecological harm to soil and groundwater contamination through the improperly treated wastewater effluent. This study tested the effect of the bio-augmentation product BiOWiSH® Septic Rescue of BiOWiSH® Technologies International, Inc. (hereafter referred to as BiOWiSH) on the biological treatment of residential septic tanks. BiOWiSH is meant to act as a bio-augmentation product through the addition of a proprietary blend of Bacillus and Lactic Acid producing bacteria. These microbes act as a biocatalyst to enhance and encourage a range of hydrolytic, oxidative, and reductive biochemical reaction and promote digestion of bio solids and ammonification within the septic tanks. To test the effect of BiOWiSH on the treatment of residential septic tanks, four 32-gallon tanks were constructed and filled with water and primary sludge from the primary clarifier at the San Luis Obispo Water Resource Recovery Facility. Two tanks were dosed with the recommended amount of BiOWiSH; one tank had no additive biological treatment and served as the control; one tank was dosed with RID-X® Septic Maintenance, a leading competitive product (hereafter referred to as RID-X). Each tank functioned as a plug-flow reactor. Primary sludge and tap water was added daily and effluent was sampled on a daily or weekly basis, based on the parameters being tested. Effluent water samples were tested for removal of ammonia, nitrates, total suspended solids, and biological oxygen demand. Temperature and pH were also recorded. v These analyses indicated no significant advantage from the addition of BiOWiSH in the reduction of ammonia, total suspended solids, or biological oxygen demand over the control tank or the tank dosed with the RID-X competitive product. Nitrates (in the form of nitrate and nitrite) did not form in any of the tanks. Future studies are needed to validate these results. Additional studies should include an analysis of experimental time frames, sampling frequency, and testing additional products designed to rescue failed or failing septic systems. BiOWiSH should also be tested further in its potential ability to enhance the biological treatment of septic tank effluent once the wastewater has entered aerobic leach fields.

2 pp. / Originally published: 2001 / An onsite sewage treatment system or "septic system" is effective way to safely recycle household wastewater back into the natural environment. The key to effective treatment is proper design, system installation, responsible operation, and periodic maintenance. This article provides information about how to improve septic system performance by taking simple steps at home.

Groundwater is an important resource that is relied on by approximately half of the world’s population for drinking water supply. Source water protection efforts rely on an understanding of flow and contaminant transport processes in aquifers. Bedrock aquifers are considered to be particularly vulnerable to contamination if the overburden cover is thin or inadequate. The objective of this study is to further the understanding of modeling, sampling, and the potential for anthropogenic contamination in fractured bedrock aquifers. Two numerical modeling studies were conducted to examine geochemical groundwater sampling using multi-level piezometers and the role of discretization in a discrete fracture radial transport scenario. Additionally, two field investigations were performed to study the variability of bacterial counts in pumped groundwater samples and the potential for anthropogenic contamination in a bedrock aquifer having variable overburden cover in a semi-urban setting. Results from the numerical modeling showed that choosing sand pack and screen materials similar in hydraulic conductivity to each other and the fractures intersecting the borehole can significantly reduce the required purge volume. Spatiotemporal discretization was found to be a crucial component of the numerical modeling of solute transport and verification of the solution domain using an analytical or semi-analytical solution is needed. Results from the field investigations showed fecal indicator bacterial concentrations typically decrease on the order of one to two orders of magnitude from the onset of pumping. A multi-sample approach that includes collection at early-time during the purging is recommended when sampling fecal indicator bacteria for the purpose of assessing drinking water quality. Surface contaminants in areas with thin or inadequate overburden cover can migrate quickly and deeply into the bedrock aquifer via complex fracture networks that act as preferential pathways. While the presence of fecal indicator bacteria in groundwater samples signifies a possible health risk through human consumption, it was the suite of pharmaceuticals and personal care products that allowed the identification of septic systems and agriculture as the dominant sources of contamination. Land-use planning and source water protection initiatives need to recognize the sensitivity of fractured bedrock aquifers to contamination. / Thesis (Ph.D, Civil Engineering) -- Queen's University, 2011-02-28 17:27:54.806

Onsite wastewater treatment systems (OWTSs) are a commonly used means of wastewater treatment in the Dickinson Bayou watershed which is located between Houston and Galveston. The Dickinson Bayou is classified as "impaired" by the Texas Commission on Environmental Quality due to high levels of bacteria, specifically E. coli. Failing OWTSs within the bayou's watershed are possible sources for the impairment of the bayou. Conventional OWTSs, comprised of a septic tank and a soil absorption field, rely heavily on soil treatment of effluent. The type of soils is a significant factor in treatment capabilities. In the Dickinson Bayou watershed, soils are primarily composed of clays, which are known to be problematic for conventional systems as they restrict water flow and create perched water tables. These perched water tables may contribute to surface runoff during rainfall events. The HYDRUS modeling software for water and solute flow through variably saturated media was used to simulate OWTSs in the Dickinson Bayou watershed. HYDRUS was used to simulate conventional septic systems with soil absorption fields, aerobic treatment units (ATUs) with spray dispersal systems, and mound systems. Results found that the simulated conventional systems fail due to high water tables and clay soils. However, system failure in the watershed remains uncertain due to lack of field data for validation. The alternative systems mitigate these issues, but ATUs can lead to higher contamination levels without proper maintenance. Therefore, mound systems are the suggested alternative for OWTSs in the watershed.

The sustainability of water resources is an international and national concern. With increased human activity, water distribution on a global, regional, and local scale has been negatively impacted. Managing water resources also includes managing wastewater. A promising solution to the issues of water scarcity and distribution in the environment is the reuse of wastewater. Wastewater is produced from various sources (domestic, industrial, and commercial); however, if this water is able to be reused closer to the source of generation it could positively impact water distribution. In the United States, approximately 25% of domestic wastewater is treated in onsite wastewater treatment systems OWTS (mainly septic tanks and drainfields). However, septic systems are not efficient at removing nitrogen and pathogens, making them a risk to public health and the environment. In recent years, advanced onsite wastewater treatment systems have been developed to reduce contaminants into the environment. These systems are effective at removing contaminants but often require many mechanical parts and have high energy requirements. These additional components require homeowners to perform more maintenance on advanced OWTS than conventional systems or pay for maintenance to be performed. Passive Nitrogen Reduction Systems (PNRS) are being developed that provide high levels of nutrient removal while keeping maintenance requirements and costs low for the homeowner. (PNRS) use two-stage packed bed bioreactors to remove nitrogen from wastewater via nitrification (Stage I) and denitrification (Stage II). Our laboratory has developed a two-stage bench scale PNRS that uses ion exchange (IX) materials, clinoptilolite and scrap tire chips, to enhance the removal of nitrogen from wastewater by buffering transient loads to the biological processes. Pathogens can be present in domestic wastewater and if untreated can be released to groundwater and open water bodies endangering the health of the public. PNRS have the potential to reduce pathogenic microorganism released into the environment, however; the reduction of pathogens in PNRS that include IX media had not previously been studied. In this research, E. coli was used as a fecal indicator bacteria (FIB) because of its simplicity and national and worldwide acceptance. In our study, the performance of a PNRS with and without IX media was evaluated. Hourly studies were performed to determine the removal efficiency of E. coli from the system under varying hydraulic loading rates. Biofilm detachment experiments were conducted to measure E. coli adsorption and growth patterns within the column reactors. Batch adsorption experiments were completed to determine the effect of different types of media with and without IX material on E. coli growth over extended time periods. E. coli enumeration data from the hourly experiments demonstrated that there was a 0.84 log reduction of E. coli throughout the PNRS from the septic tank effluent to the final effluent released from the system. The evening and afternoon periods showed a higher reduction of E. coli compared with the morning period. Removal efficiencies were greater in the first stage of treatment (nitrification) as compared to the second stage treatment (denitrification). However, these variances did not result in significant differences in overall E. coli removal efficiency. Adsorbed E. coli were evenly distributed in the column containing IX media, while a decrease in adsorbed E. coli with depth was observed in the column without IX media. Batch adsorption studies revealed that when E. coli are present in wastewater solution with media, E. coli are initially adsorbed but can grow in the system after 6-12 hours. This growth indicates that other FIB should also be used to determine the fate of pathogens in PNRS. Based on all E. coli enumeration experiments, the PNRS developed reduce E. coli by almost 85%; however, this reduction is not adequate to meet onsite water reclamation regulations. Further studies are needed to develop tertiary treatment for pathogen reduction and wastewater reuse.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第22768号 / 工博第4767号 / 新制||工||1745(附属図書館) / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 田中 宏明, 教授 清水 芳久, 教授 藤井 滋穂 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Pharmaceuticals, personal care products (PPCPs) and other trace organic contaminants (TOrCs) encompass a diverse group of chemicals that are not currently monitored or regulated in US drinking water or wastewater. Researchers have found low levels of TOrCs in aquatic and terrestrial environments all over the globe, and observed negative effects on impacted biota. The primary source of TOrCs in the environment is domestic wastewater discharges. Centralized wastewater treatment plants present greater risks on a global scale, but on a local scale, onsite treatment systems may have more potent impacts on resources that are invaluable to residents, including groundwater, surface waters, and soils. The objective of this thesis is to identify and characterize promising treatment technologies for onsite TOrC remediation. Receptors who could be impacted by TOrC discharges are assessed, and applications that may require alternative treatment are identified. The best treatment technologies are recognized as those that protect sensitive environmental receptors, provide permanent removal pathways for as many TOrCs as possible, and are not prohibitively expensive to install or maintain. Findings from a pilot study show increased removal of conventional pollutants and TOrCs in an aerobic treatment unit (ATU), two types of biofilter, and a hybrid constructed wetland, all relative to septic tank effluent. The constructed wetland achieved the highest nutrient removals with TN concentrations below 10 mg/L throughout the study. A system with an ATU and peat biofilters achieved the highest removals of persistent pharmaceuticals carbamazepine and lamotrigine (>85% and >95%, respectively). / Master of Science / Trace organic contaminants (TOrCs) are chemicals found in pharmaceuticals, laundry detergents, shampoo, flame retardants, food preservatives, and many other products used in a typical home, which are not currently monitored or regulated in US drinking water or wastewater. Researchers have found low levels of TOrCs in waters and soils all over the globe, and observed negative effects on the plants and animals that live in those environments. The primary source of TOrCs in the environment is treated wastewater from centralized wastewater treatment plants, which is usually released to rivers, lakes, and other surface waters. People in rural communities also have TOrCs in their wastewater, which is normally treated using a septic system. Water released in the septic field can add TOrCs to septic field soils, groundwater sources, or nearby surface water sources, and from there these chemicals have the potential to impact human health, soil fertility, livestock health, or fish and other living things in surface waters. The objective of this thesis is to identify and characterize promising treatment technologies that would prevent or limit TOrC impacts to these important resources, which are called “receptors.” Receptors who could be impacted by TOrC discharges are assessed, and the situations in which these treatment technologies would be necessary are identified. The best treatment technologies are recognized as those that protect sensitive environmental receptors, remove as many TOrCs as possible, and are affordable to install or maintain. An experiment was designed to compare the performance of three different technologies that could remove TOrCs from septic tank effluent, including a peat filter and a constructed wetland. The constructed wetland removed the most nitrogen (total nitrogen <10 mg/L throughout the study), and a system with a peat filter removed the greatest amounts of persistent pharmaceuticals carbamazepine and lamotrigine (averaging >85% and >95%, respectively).