Approximately 25% of households in the U.S. treat their wastewater onsite using conventional onsite wastewater treatment systems (OWTS). These systems typically include a septic tank or a series of septic tanks followed by a soil absorption system. They effectively remove biochemical oxygen demand (BOD), total suspended solids (TSS), fats and grease but are not designed to remove significant amounts of nitrogen. High nitrogen loading to coastal and ground waters can be dangerous to aquatic life and public health. Hence, there is a need for advanced onsite wastewater treatment systems that can effectively remove nitrogen. Making enhanced nitrogen removal for OWTS as our primary goal, a laboratory scale Hybrid Adsorption and Biological Treatment Systems (HABiTS) was developed and upon observation of its effective nitrogen removal capacity, a pilot demonstration study with two side-by-side HABiTS, one with recirculation and one without recirculation (only forward flow) were constructed and tested at the Northwest Regional Water Reclamation Facility in Hillsborough County (Florida). HABiTS employ biological nitrogen removal and ion exchange for effective nitrogen removal. HABiTS is a two-stage process which uses nitrification for the oxidation of ammonium to nitrate and ion exchange for ammonium adsorption that helps buffer transient loading and also acts as a biofilm carrier in its stage 1 biofilter and it uses tire-sulfur hybrid adsorption denitrification (T-SHAD) in its stage 2 biofilter. These sulfur pellets help promote sulfur oxidation denitrification (SOD) and tire chips are used for nitrate adsorption during transient loading conditions, as biofilm carriers for denitrifying bacteria, and can also be used as organic carbon source to promote heterotrophic denitrification because they leach organic carbon. For this research, HABiTS without recirculation is considered as the control system and the performance of HABiTS with recirculation was tested for its ability to further enhance nitrogen removal from HABiTS. Nitrified effluent recirculation is a common strategy employed in wastewater treatment for enhanced nitrogen removal. It is the reintroduction of semi-treated wastewater to pass through an anoxic pre-treatment chamber to achieve better quality effluent. Recirculation is said to improve and consistently remove nitrogen at any hydraulic loading rate and/or nitrogen concentration. This is because of the dilution of high BOD septic tank effluent with nitrified effluent which lowers COD:TKN ratio and also improves mass transfer of substrates in the stage 1 biofilter. Recirculation also provides some pre-denitrification in the pre-treatment chamber, thereby reducing nitrogen load on the system. The HABiTS with recirculation (R) was run at 1:1 ratio of nitrified effluent recirculation rate to the influent flow rate for 50 days, and at 3:1 ratio for the remaining period of this research (200 days). The forward flow system (FF) was run under constant conditions throughout the research and comparisons between the two systems were made for different water quality parameters (pH, DO, conductivity, alkalinity, TSS, chemical oxygen demand (COD), total nitrogen (TN), total phosphorus (TP) and various nitrogen species). The final effluent ammonium results showed that the system with recirculation removed consistently > 80% NH4+-N during 1:1 and 3:1 recirculation ratios whereas the forward flow system achieved 57% removal. Further, an average of 81% total inorganic nitrogen (TIN) removal from the system influent was seen in the recirculation systems final effluent when compared to an average of 55% in forward flow systems final effluent. This research explains in detail, the impact of nitrified effluent recirculation on enhanced nitrogen removal in onsite systems and the results presented in this thesis proved that nitrified effluent recirculation provides promising enhanced nitrogen removal in an onsite wastewater treatment system.

High nutrient loading into groundwater and surface water systems has deleterious impacts on the environment, such as eutrophication, decimation of fish populations, and oxygen depletion. Conventional onsite wastewater treatment systems (OWTS) and various waste streams with high ammonium (NH4+) concentrations present a challenge, due the inconsistent performance of environmental biotechnologies aimed at managing nutrients from these sources. Biological nitrogen removal (BNR) is commonly used in batch or packed-bed reactor configurations for nitrogen removal from various waste streams. In recognition of the need for resource recovery, algal photobioreactors are another type of environmental biotechnology with the potential for simultaneously treating wastewater while recovering energy. However, irrespective of the technology adopted, outstanding issues remain that affect the consistent performance of environmental biotechnologies for nitrogen removal and resource recovery. In OWTS, transient loading can lead to inconsistent nitrogen removal efficiency, while the presence of high free ammonia (FA) can exert inhibitory effects on microorganisms that mediate transformation of nitrogen species as well as microalgae that utilize nitrogen. Therefore, to overcome these challenges there have been experimental studies investigating the addition of adsorption and ion exchange (IX) media that can temporarily take up specific nitrogen ions. Bioreactors comprised of microorganisms and adsorption/IX media can attenuate transient loading as well as mitigate inhibitory effects on microorganisms and microalgae; however, the interplay between physicochemical and processes in these systems is not well understood. Therefore, the main objective of this dissertation was to develop theoretical and numerical models that elucidate the complex interactions that influence the fate of chemical species in the bioreactors To achieve this objective and address the issues related to improving the understanding of the underlying mechanisms occurring within the environmental biotechnologies investigated, the following three research studies were done: (i) experimental and theoretical modeling studies of an IX-assisted nitrification process for treatment of high NH4+ strength wastewater (Chapter 3), (ii) theoretical and numerical modeling of a hybrid algal photosynthesis and ion exchange (HAPIX) process for NH4+ removal and resource recovery (Chapter 4), and (iii) mathematical and numerical modeling of a mixotrophic denitrification process for nitrate (NO3-) removal under transient inflow conditions (Chapter 5). The experimental results for the IX-assisted nitrification process showed that by amending the bioreactor with zeolite, there was a marked increase in the nitrification rate as evidenced by an increase in NO3 production from an initial concentration of 3.7 mg-N L-1 to 160 mg-N L-1. This increase is approximately an order of magnitude greater than the increase in the reactor without chabazite. Therefore, the experimental studies provided support for the hypothesis that IX enhances the nitrification process. To garner further support for the hypothesis and better understand the mechanisms in the bioreactor, a novel mathematical model was developed that mechanistically describes IX kinetics by surface diffusion coupled with a nitrification inhibition model described by the Andrews equation. The agreement between the model and data suggests that the mathematical model developed provides a theoretically sound conceptual understanding of IX-assisted nitrification. A model based on the physics of Fickian diffusion, IX chemistry, and algal growth with co-limiting factors including NH4+, light irradiance, and temperature was developed to describe a batch reactor comprised of microalgae and zeolite. The model can reproduce the temporal history of NH4+ in the reactor as well as the growth of microalgae biomass. The mathematical model developed for the HAPIX process balances between simplicity and accuracy to provide a sound theoretical framework for mechanisms involved. In OWTS, transient inflow conditions have an influence on the performance of environmental biotechnologies for nitrogen removal. Prior experiments have shown that for denitrification, a tire-sulfur hybrid adsorption and denitrification (T-SHAD) bioreactor consistently removes nitrogen under varying influent flow and concentration conditions. To enhance the understanding of the underlying mechanisms in the T-SHAD bioreactor, a mathematical model describing mass transport of NO3- and SO42- in the aqueous phase and mixotrophic denitrification was developed. Additionally, a numerical tool to solve the mathematical model was implemented and compared to previously conducted experiments. Results from the numerical simulations capture the trend of the experimental data showing approximately 90% NO3- -N removal under varying flow conditions. Moreover, the model describes the effluent characteristics of the process showing a transient response in correspondence the changes in fluid velocity. The new tools developed provide new insight into the underlying mechanisms of physical, chemical, and biological processes within these bioreactors. The tools developed in this dissertation have a potential broad impact in environmental biotechnology for wastewater treatment in on-site systems, for treatment of high strength wastewater, and can be extended easily for stormwater management systems aimed at mitigating high nutrient loading to the environment.

In recent decades, scientific insight into the chemistry of water has increased enormously, leading to the development of advanced wastewater and water purification technologies. However, the quality of freshwater resources has continually deteriorated worldwide, both in industrialized and developing countries. Although traditional wastewater technologies focus on the removal of suspended solids, nutrients and bacteria, hundreds of organic pollutants occur in wastewater and urban surface waters. These new pollutants are synthetic or naturally occurring chemicals that are not often monitored in the environment but have the potential to enter the environment and cause known or suspected adverse ecological and / or human health effects. Collectively referred to as the "emerging contaminants," they are mostly derived from domestic use and occur in trace concentrations ranging from pico to micrograms per liter. Environmental contaminants are resistant to conventional wastewater treatment processes and most of them remain unaffected, leading to the contamination of the receiving water. As such, there is a need for advanced wastewater treatment process that is capable of removing environmental contaminants to ensure safe fresh water supplies. This book explains the biological and chemical wastewater treatment technologies. The biological wastewater treatment processes presented include: (1) bioremediation of wastewater such as aerobic and anaerobic treatment; (2) phytoremediation of wastewater using engineered wetlands, rhizofiltration, rhizodegradation, phytodegradation, phytoaccumulation, phytotransformation and hyperaccumulators; and (3) mycoremediation of wastewater. The chemical wastewater treatment processes discussed include chemical precipitation, ion exchange, neutralization, adsorption and disinfection. In addition, the book describes wastewater treatment plants in terms of plant size, layout and design as well as installation location. Also presenting the latest, innovative effluent water treatment processes, it is a valuable resource for biochemical and wastewater treatment engineers, environmental scientists and environmental microbiologists.

Wastewater represents an alternative to freshwater if it can be treated successfully for re-use applications. Promising techniques involve photocatalysis, photodegradation, adsorption, bioreactors, nanocomposites, nanofiltration and membranes. Keywords: Wastewater Treatment, Biohydrogen Production, Bioethanol Production, Biological Wastewater, Carbon Nanotubes, Dairy Wastewater, Graphene-based Nanocomposites, Hormones in Wastewater, Malachite Green Removal, Membrane Bioreactors, Nanocomposites, Nanofiltration, Nanomembranes, Nanotubes, Organic Pollutants, Pesticides Removal, Photocatalysis, Photodegradation, Reversed Osmosis, Textile Wastewater.

"This manual contains overview information on treatment technologies, installation practices, and past performance."--Introduction.

The papers in this proceedings were presented at the World Environmental & Water Resources Congress 2009, which was held in Kansas City, Missouri from May 17 to 21. This annual conference is an important opportunity for professionals in the environmental and water resources fields to convene and focus on issues facing our world. The theme of this year s technical program is the Great Rivers of the World. This proceedings illuminates the engineering challenges of addressing the important environmental and development issues while focusing on the need for a sustainable future.

There is an urgent need to develop ammonia removal treatment systems for municipal and industrial wastewater treatment due to the increasingly stringent ammonia effluent discharge regulations implemented by Canada, the United States, and the European Union. The objective of this dissertation is to develop new understanding and advance the current design and operation of total ammonia nitrogen (TAN) removal via the moving bed biofilm reactor technology (MBBR) for municipal and industrial wastewaters. The first specific objective is to develop a passive, low operationally intensive, efficient and robust design strategy for municipal wastewater treatment to achieve partial nitritation (PN) as a pre-treatment to anammox treatment without using control strategies such as operating at low dissolved oxygen, or the use of inhibitors. This first objective includes developing new knowledge of the biofilm, biomass and microbiome of attached growth PN systems. The second specific objective is to investigate the impact of defining a maximum biofilm thickness, via bio-carrier design, to enhance the effects of free nitrous acid inhibition for PN of municipal wastewaters. The third objective is to investigate the effect of influent copper concentration on nitrifying MBBR systems over long-term operations, to demonstrate the feasibility of the nitrifying MBBR as a solution for TAN removal from gold mining wastewaters. The results pertaining to the first objective, achieved via a study investigating the operation of a nitrifying moving bed biofilm reactor at elevated TAN surface area loading rates (SALRs) of 3, 4, 5, and 6.5 g TAN/m2∙d with the aim of achieving passive PN, demonstrates that operating at a TAN SALR value of 6.5 g TAN/m2∙d can achieve PN without restricting dissolved oxygen or using inhibitors. Operating at a TAN SALR value of 6.5 g TAN/m2∙d achieves a TAN surface area removal rate (SARR) of 3.5 g TAN/m2∙d, and a nitrite accumulation of 99.8% of the oxidized TAN, demonstrating the suppression of nitrite oxidizing bacteria (NOB) activity, while achieving elevated TAN SARR values. At the molecular-scale, there is a statistically significant change in the ammonia oxidizing bacteria (AOB) to NOB ratio from 1:2.6 to 8.7:1 as the TAN SALR increases from 3 to 6.5 g TAN/m2∙d; however, even at a TAN SALR value of 6.5 g TAN/m2∙d there is an NOB abundance of approximately 2%; thus demonstrating that NOB remain present in the biofilm, while their activity is suppressed by operation at elevated TAN SALR values. Furthermore, this system was shown to achieve stable PN consistently for over a period of 10 months of operation, demonstrating a robust, passive, low operational strategy for attached growth PN. The second objective of this dissertation is addressed through a study that compared the carrier design of defined maximal biofilm thickness (z-prototype carrier) to undefined maximal biofilm thickness (chip-prototype carrier) for PN via free nitrous acid inhibition of tertiary, low carbon, municipal wastewaters. The study demonstrates that defined maximal biofilm thickness is a preferred design choice to achieve attached growth PN. The chip-prototype carrier shows biofilm thicknesses and biofilm mass values that are ten-fold higher than the z-prototype carrier, which is shown to contribute to the impact of free nitrous acid on AOB and NOB activities. The z-prototype carrier shows PN is achieved after 3 hours of exposure to free nitrous acid while the chip-prototype carrier does not achieve PN within this same time of exposure. Therefore, the defined maximal biofilm thickness carrier is identified in this research as the preferred design option to achieve attached growth PN for municipal, low carbon, tertiary wastewater treatment. The results of the third objective, achieved via a study investigating the effects of influent copper concentrations on nitrifying MBBR during long term operations to gold mining wastewaters, demonstrates that there is no AOB inhibition in attached growth systems exposed to 0.1, 0.3, 0.45, and 0.6 mg Cu/L for long exposure times. A trend of increasing nitrite accumulation with increasing influent copper concentrations is shown, indicating that NOB inhibition occurs at influent copper concentrations of 0.3 mg Cu/L and greater, with the greatest NOB inhibition observed with an influent copper concentration of 0.6 mg/L. There is no statistically significant difference in biofilm characteristics at the copper concentrations tested; however, there is a trend of increasing biofilm thickness and biofilm roughness with increasing copper concentrations. This study demonstrates the resilience of the nitrifying biofilm to copper inhibition and demonstrates that the nitrifying MBBR is a promising system for removing TAN in mining wastewater in the presence of copper.