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With the ever increasing demand for potable water due to the continued increase in population coupled with the threat of California’s current drought, water will remain a limited resource that must be managed responsibly. In order to strategically plan and manage water use in the most beneficial manner, water providers must take into account all sources of water, including recycled water and their applications. Recycled water as a source for supplementing high quality potable water is a sustainable strategy that will prove to be an essential tactic in any water management plan. The purpose of this project is to emphasize the importance of supplementing potable water in the City of Banning by discussing the characteristics of California’s current water drought; evaluating the City of Banning’s available water supplies and current water demand; discussing the Soil Aquifer Treatment process; summarizing California’s regulations related to recycled water; and discussing the quality of recycled water available at NP-1, an unequipped City owned water well, by examining water quality testing on water samples taken from NP-1. Analysis of water available at NP-1 showed that with additional disinfection, the water pumped from NP-1 could meet the recycled water requirements in order to be used on a local golf course. The local golf course is currently being irrigated with potable water, which would be supplemented with the recycled water from NP-1.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19987号 / 工博第4231号 / 新制||工||1654(附属図書館) / 33083 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 伊藤 禎彦, 教授 田中 宏明, 准教授 西村 文武 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Managed aquifer recharge (MAR) consists of artificially replenishing groundwater to facilitate reuse and/or the associated environmental benefits. Meanwhile, soil aquifer treatment (SAT) is a process of geo-purification designed and operated to improve the quality of the infiltrating water and is thus a type of MAR. SAT consists of a basin operating under rotation of drying and wetting periods. Often, SAT involves water of impaired quality applied onto soil and consequently it implies various risks of health, geochemical and physical nature with difficult or irreversible remediation. To study the effect of pre-treatment on SAT a pilot plant including conventional activated sludge (CAS), a membrane bioreactor (MBR), tertiary and secondary vertical flow reed beds (VFRB) and SAT soil columns. The sludge retention time (SRT) in the CAS and MBR processes was changed every 6 months to look at the impact of SRT on SAT. Each unit and treatment train effluent was characterised to determine the impact of effluent quality on SAT performance. This study showed that tertiary VFRB, especially when fed with MBR effluent, was the best option for SAT and irrigation reuse as it provided the best compliance with reuse standards and the best fertilisation potential. However, long-term clogging occurred in SAT after tertiary VFRB, suggesting the need for a longer resting period or shorter wetting period. This study also highlighted the importance of total suspended solids (TSS) content for SAT removal mechanisms and infiltration rate. In particular, SAT fed with high TSS content effluent was susceptible to temperature variation. Hence the duration of wetting and flooding periods should be adapted according to the season. Further, variation in SRT only indirectly affected pollutants removal by the system including CAS treatment set up at 6 d SRT where the N compounds balance was favourable to an autotrophic N removal.

Constructed wetlands (CW) and soil aquifer treatment (SAT) represent natural wastewater treatment systems (NWTSs). The high costs of conventional wastewater treatment techniques encourage more studies to investigate lower cost treatment methods which make these appropriate for developing and also in developed countries. The main objective of this research was to investigate the removals of nutrients and organic micropollutants (OMPs) through SAT, CW and the CW-SAT hybrid system. CWs are an efficient technology to purify and remove different nutrients as well as OMPs from wastewater. They removed most of the dissolved organic matter (DOC), total nitrogen (TN), ammonium and phosphate. Furthermore, CWs aeration could be used as one of the alternatives to reduce CWs footprint by around 10%. The vegetation in CWs plays an essential role in the treatment especially for nitrogen and phosphate removals, it is responsible for the removal of 15%, 55%, 38%, and 22% for TN, dissolved organic nitrogen (DON), nitrate and phosphate, respectively. CWs achieved a very high removal for some OMPs; they attenuated acetaminophen, caffeine, fluoxetine and trimethoprim (>90%) under different redox conditions. Moreover, it was found that increasing temperature (up to 36 C) could enhance the removals of atenolol, caffeine, DEET and trimethoprim by 17%, 14%, 28% and 45%, respectively. On the other hand, some OMPs, were found to be removed by vegetation such as: acetaminophen, caffeine, fluoxetine, sulfamethoxazole, and trimethoprim. Moreover, atenolol, caffeine, fluoxetine and trimethoprim, showed high removal (>80%) through SAT system. It was also found that, temperature increasing and using primary instead of secondary effluent could enhance the removal of some OMPs. The CWs performance study showed that these systems are adapted to the prevailing extreme arid conditions and the average percent removals are about, 88%, 96%, 98%, 98% and 92%, for COD, BOD and TSS, ammonium and phosphate, respectively. Additionally, the natural hybrid system (CW-SAT) can provide an effective treatment technology of reclaimed water for replenishing aquifers and subsequent reuse. This hybrid system embodied the performance advantages of both processes and exhibits a high potential for removal of OMPs, nutrients, metals as well as pathogens, bacteria and viruses.

Soil aquifer treatment (SAT) during managed aquifer recharge has been studied as a method of providing additional environmental barriers to pathogens and contaminants in indirect potable reuse (IPR) applications. A soil column study was conducted by Hampton Roads Sanitation District in order to evaluate the effectiveness of SAT, as a component of its IPR project involving the replenishment of the Potomac Aquifer System (PAS), in providing a sustainable source of drinking water. Four packed soil columns were constructed with sand from the PAS and were designed to simulate the travel time of 3 days and 30 days. The tests conducted aimed at evaluating pathogen removal (MS2, E. coli and Cryptosporidium oocysts); evaluating attenuation of regulated (nitrate, nitrite, bromate, trihalomethane (THM), haloacetic acids (HAA), organic carbon) and unregulated contaminants of concern that affect drinking water quality. Effective pathogen removal was observed with 6 to 7-log removals of MS2 and E. coli and 3 to 5-log removals of microbeads, used as a surrogate for Cryptosporidium. Removal across 3 day columns was comparable to 30-day columns but the potential to achieve higher removal with longer retention time was acknowledged. Nitrate, bromate, THMs and HAAs were completely reduced in 30-day columns. Total organic carbon was removed at 25 – 35% in all four columns. Seven out of the 106 contaminants of emerging concern (CEC) tested were consistently detected in the column feed and effluent at concentrations greater than 100 ng/L; some compounds showed potential for removal while no conclusive results were drawn for the remaining compounds. / MS / Potable reuse is a sustainable solution to the increasing water demands of the present and more so the future. Hampton Road Sanitation District (HRSD) aims to treat effluent from its wastewater treatment plants using advanced treatment process for direct recharge of the Potomac aquifer system. This is a method of indirect potable reuse termed as managed aquifer recharge (MAR). MAR can provide additional environmental barriers to contaminants present in water through a process of natural attenuation called soil aquifer treatment (SAT). A soil column study was conducted at HRSD’s pilot scale facility in order to asses SAT under controlled conditions at a meaningful scale. Attenuation of pathogens; regulated contaminants (nitrate, nitrite, bromate, etc.) and contaminants of emerging concern was evaluated through the soil columns. The results showed effective removal of most contaminants of interest which demonstrated that SAT potentially improves water quality and meets public health standards in potable reuse applications.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19983号 / 工博第4227号 / 新制||工||1654(附属図書館) / 33079 / 京都大学大学院工学研究科都市環境工学専攻 / (主査)教授 伊藤 禎彦, 教授 米田 稔, 准教授 西村 文武 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21097号 / 工博第4461号 / 新制||工||1693(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 伊藤 禎彦, 教授 田中 宏明, 准教授 西村 文武 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Soil aquifer treatment (SAT) of treated wastewater performance was evaluated across published full-scale and lab-scale studies developing insights on the aquifer and operational factors that affect SAT efficacy. The goal of this study was to develop a basis for predicting the contaminant removal capabilities of any given aquifer during managed recharge with treated wastewater. Over 40 published SAT studies were reviewed and systematically compared to determine the influence of five major factors on contaminant removal performance: geologic composition, geochemical conditions, hydrogeological conditions, operational methods, and source water quality. Removal mechanisms for standard contaminants (dissolved and total organic carbon, nitrogen, and pathogens) were considered for each factor. By supplementing the theoretical understanding of contaminant removal in SAT systems with full scale and lab scale results, recommendations were developed for practical and effective SAT feasibility standards. SAT of standard contaminants was found to be most effective in aquifers with a water table below 20-meters. SAT was also most favorable for source water with 10 to 20-mg/L of bulk organics and less than 10-mg/L of total nitrogen. Moreover, extended residence times in the saturated zone provide little additional bulk organic and nitrogen removal for aquifers with vadose zones that achieve more than 85% of total bulk organic removal. The results of this study should enhance feasibility studies for future soil aquifer treatment projects, thereby facilitating the use of sustainable indirect potable reuse.

This study evaluates soil properties that impact the effectiveness of soil aquifer treatment (SAT) as a polishing step to the remove two classes of ECs from wastewater effluent: pharmaceuticals and personal care products (PPCPs), and engineering nanomaterials (ENMs). In recent years, it has been determined that elevated levels of emerging contaminants (ECs) are being released into the environment with wastewater effluent. ECs are proven to cause adverse environmental and health effects as a result of long-term exposure. It is important to evaluate sustainable solutions to improve the current methods of wastewater treatment to address these ECs. Soil aquifer treatment (SAT) is a sustainable, cost effect treatment alternative to advanced treatment at a wastewater treatment plant. SAT replenishes local groundwater supplies while allowing for indirect potable reuse, if contaminants of concern such as ECs can be effectively removed from the water. Since wastewater effluent can contain a variety of contaminants with myriad physical and chemical properties, understanding the potential of the aquifer itself to provide EC removal is a key step in establishing SAT as a viable treatment alternative. Peer-reviewed research studies were analyzed to determine the soil properties that affect the fate and transport of ECs in the aquifer environment. The data was complied to produce recommendations for an effective SAT site. Physical and chemical properties of the soil facilitate contaminant removal as the groundwater flows through the aquifer. This study determined that removal of ECs from effluent had a correlation with (1) high clay content, (2) small Darcy Velocity, (3) high soil organic matter content, and (4) low sand content. Based on the 6 peer-reviewed research studies reviewed, the removal of nanomaterials is affected by clay content and sand content, but not soil organic matter content. Conversely, the removal of PPCPs is affected by clay content and soil organic mater content, but not sand content. It can be concluded that two different removal mechanisms facilitate the removal of nanomaterials versus PPCPs; physical removal for nanomaterials and chemical removal (sorption) for PPCPs. Clay facilitates the removal of both contaminants. The small soil diameter of clay forms smaller pores in the soil media. This causes increased pore straining, while also restricting the flow through the soil, which increases the contact time between the soil particle and the ECs. Additionally, clay has a large surface area, which increases surface interactions, such as sorption, of the EC to the surface of the clay particle.