Arizona’s Cave Creek plant was removed from service in November 2009. The plant is now being redesigned to improve efficiency and handle the town’s growing population. For this reopening project, a preliminary design and hydraulic profile were created, design flow rates were determined, recommendations for potential effluent uses were made, and overall economic evaluation of capital and operational costs were completed. Several design alternatives were made initially, and the final design was chosen based on an analysis of population, cost, environmental factors and efficiency. The major changes made to the plant include addition of several screens, a completely updated secondary treatment section and a different disinfection technique. Cost of implementation –including equipment, construction and installation, cost of maintenance, and total cost of electricity to run the plant –were the main factors in the cost analysis. Several recommendations for the treated wastewater effluent were made based on the water quality provided by the plant. This project will optimize the Cave Creek plant and provide a clean alternative method for providing freshwater to Arizona.

The Cave Creek Water Reclamation Plant in Arizona was closed in 2009 because of slow population growth. Current population growth has created an opportunity to reopen the plant. Design improvements will start with water intake at the influent pump station, which passes through a series of screens and through the grit removal station. At the primary clarifier, most of the water will pass through to the aerator, while the rest will go to the sludge holding tank to be dewatered. The water from the sludge will be returned to the influent pump station and sent back through the process, and the dry sludge will be taken to a landfill. After passing through the aerator, a second sludge step will be conducted in which most of the water will pass through sand filters, and the rest will be transferred into the sludge holding tank. From the sand filter, the water will make its way through ultraviolet disinfection. The ultraviolet lamps will include quartz sleeves for reduced maintenance, and low-pressure lamps will be used to reduce energy use and carbon footprint. After disinfection, sodium hypochlorite will be injected to further disinfect the water. The finished product will be stored in the effluent storage tanks and then sent down to the wastewater treatment plant for further treatment.

Numerous heat exchanger designs are used in industry to balance heat transfer rate, robustness and cost through specification of materials, designs and flow regimes. The heat exchanger network cart will be used by the Department of Chemical and Environmental Engineering for undergraduate students to facilitate learning and understanding of the operation and variation of heat exchangers. The network cart encompasses a system with four heat exchangers that compare the effects of heat transfer rates due to differences between materials and form factors. The network is made with corrosion-resistant materials, a self-contained electrically heated hot water system and a set of standard operating procedures for ease of maintenance with a guaranteed minimum service life of 15 years.

The 30 micron primary drum filters in the Biosphere 2 life-support system required backwash because they were failing to remove dissolved and suspended organic material from the Biosphere 2 ocean. The goal of the backwash treatment was to identify optimal conditions for reuse while simultaneously minimizing any potential waste stream. This required multiple mass balances, process train designs, and ocean chemistry knowledge. Mechanical processes such as rapid sand filtration and ultrafiltration were used to remove turbidity, and chemical processes such as ozonation and ultraviolet treatment removed harmful microbes within the backwash.

There are several benefits to hydrogen polymer electrolyte membrane fuel cell technology, including a high power density and a relatively low weight. However, hydrogen gas storage can be problematic and hazardous. In addition, low-temperature fuel cells often require relatively large water-cooling systems to run efficiently.To eliminate these issues, the team’s design uses a high operating temperature and an integrated reformer, which removes the need for hydrogen storage. The reformer uses methanol and steam to produce high-purity hydrogen gas through a methanol-steam reforming reaction, and the introduction of a catalyst. The high activation energy of the reforming reaction allows easier integration with the high operating temperatures of the fuel cell: around 180 degrees Celsius. The hydrogen gas can then be isolated using a palladium membrane and fed to the polymer electrolyte membrane fuel cell stack, where hydrogen gas and oxygen come in contact with a platinum catalyst. Positive hydrogen ions are transferred through an electrolyte membrane to create power output. Potential uses of this technology include primary or secondary energy sources for residential and industrial applications.

Ethanol production begins with finely ground whole grains that are then mixed with diluted acid and cooked at high temperatures. The acid aids in the hydrolysis of the starches within the grain and provides the proper pH environment for enzymes during the saccharification process. Cooking the starches prior to saccharification further optimizes enzymatic starch breakdown into sugars. These sugars are then consumed by yeast in a fermentation process to produce ethanol. The process of enzymatic degradation and yeast fermentation yields a solution that contains approximately 16 percent ethanol. This solution also contains undigested starches, sugars and other byproducts. To produce a 95 percent solution of ethanol, this mixture goes through a distillation process whereby ethanol is separated from the remaining solution to achieve high purity. The finished product is then shipped to be diluted and distributed at an outside facility.

Global climate change, depletion of fossil fuels and a growing energy demand have created a need for reliable, safe and clean fuel alternatives to fossil fuel. Dimethyl ether is an appealing option due to its high cetane number and its low-polluting combustion. A manufacturing plant was designed and cost-evaluated for the conversion of biosolids into dimethyl ether. Biosolids, such as firewood and agricultural waste, are reformed at high temperatures to generate syngas, a mixture of hydrogen gas, carbon dioxide and carbon monoxide. A reactor was designed to react the syngas over catalyst to produce methanol. The catalyst is bifunctional and also aids in dehydration of methanol to produce dimethyl ether within the same reactor. A separation process design was created to purify dimethyl ether to ASTM fuel standards and to capture unreacted methanol for process recycling. This design is a cost-effective, safe, green alternative to fossil fuels.

The increasing demand for cloud storage has resulted in major growth for the data center industry. Cloud service providers, such as Microsoft, generate large amounts of heat at data center, which must be removed through cooling. Microsoft currently removes heat from its data centers by cycling water between cooling towers and data centers, but contaminant buildup can cause fouling in the water. This process is not sustainable because there is no current reclamation of contaminated cooling water discharge.The team’s design uses a system of membrane distillation units that use low-grade heat from the data centers and cooling potential from a local freshwater source. Design considerations included cost comparisons with current water treatment process, total utility usage required to power the units, and water purity.

Dynamic simulations can improve early stages of research and testing and can be used to help operators train, allowing them more freedom to learn from mistakes.
Integrated Modeling of Dynamic Distillation Simulations, or iMODDS, is a fully functional distillation column simulation that communicates with a distributed control system. The simulation automatically responds to input and output communications from the control system like a real distillation unit while minimizing run times. The simulation uses the Skogestad method for dynamic distillation. The distillation column was modeled using the rigorous tray model involving a linearized approach to tray hydraulics using Laplace transforms. The project encompasses only a single stage in ethanol production: the rectifying column and associated equipment. The simulation has the ability to interpret inputs and parameters, and communicates the appropriate outputs to control system software.

Low density and compression difficulty make direct piping of natural gas over long distances inefficient and costly. The liquid form of natural gas is favored by international importers due to its energy density and ease of transport. However, liquid natural gas must be vaporized before it can be used as an energy source. The essence of this design is to create a terminal capable of vaporizing 1.05 billion cubic feet of liquid natural gas per day for continuous pipeline transmission. The liquid gas is offloaded from tankers to storage tanks that maintain cryogenic conditions of -259 degrees Fahrenheit. Some liquid gas in these tanks vaporizes spontaneously, and a portion of this excess gas is routed back to the tankers, while the rest of it is recondensed for vaporization. Liquid natural gas from the storage tanks is compressed to 1,350 pounds per square inch absolute before vaporization to prepare for requisite piping conditions of 1,250 pounds per square inch and 40 degrees Fahrenheit. Heat for vaporization is supplied from the ambient environment, using either seawater or air (both options are explored in this design). In winter months, ambient conditions provide insufficient heat, so a portion of natural gas is burned to make up for this difference.