The Kinetics of Rotating Biological Contactors Treating Domestic Wastewater

Four, four-stage, laboratory scale rotating biological contactor (RBC) units were employed to develop kinetic models for the RBC process when treating domestic wastewater. The study was conducted at three different temperatures of 5 degrees C, 15 degrees C, and 20 degrees C. Each unit operated at a different constant organic loading rate taht ranged from 4 qCOD/m^2/d to 14 gCOD/m^2/d and at a constand detention time of 2 hours. Carbonaceous substrate removals measured as COD cencentrations with the four-stage RBC\u27s were 80, 85, and 90 percent for 5 degrees C, 15 degrees C, and 20 degrees C, respectively. The major part of the removal occurred in the first stages. The overall precentage removals of ammonia nitrogen were 87 to 98 percent at 15 degrees C from 91 to 99 percent at 20 degrees C depending upon the influent organic loading rate. At 5 degrees C there was no ammonia nitrogen removal. Kinetic models were devloped and kinetic constants were determined for COD and ammonia nitrogen removal in the first and succeeding stages of the RBC units. Biomass yeild, biomass stabilization, and ammonia nitrogen removal were also evaluated. Monod growth kinetics were used in the development of the models for carbonaceous substrate removal in the first stages and for ammonia nitrogen removal in the system. The temeprature dependency of each kindetic constant was determined for the range of 5 degrees C to 20 Degrees C. Steady-state kinetic models were developed, and kinetic constants were determined as a function of temperature to provide a rational design approach for the RBC process treating domestic wastewater

Experimental Measurements of Fuel Savings During Aircraft Wake Surfing

The National Aeronautics and Space Administration (NASA) Armstrong Flight Research Center (Edwards, California) completed a series of research flights to better understand the challenges of aircraft wake surfing using civilian airplanes and commercial avionics. The research flights sought to demonstrate significant fuel savings by a pair of business jets engaged in automated wake surfing using commercial off-the-shelf avionics to the fullest extent possible, including a 1090-MHz Automatic Dependent Surveillance - Broadcast (ADS-B) data link. A NASA Gulfstream C-20A airplane (Gulfstream Aerospace, Savannah, Georgia) was flown as the trail airplane within the wake of a NASA Gulfstream III (G-III) airplane. This paper presents a summary of the fuel savings measured during those flights

Evaluation of Wastewater Filtration

Tertiary filtration of secondary wastewater is frequently used to improve wastewater treatment plant effluent quality. Four experimental filter columns were operated at the Preston, Idaho, Wastewater Treatment Plant to evaluate the effectiveness of granular media, gravity filtration. The Preston plant is a trickling filter secondary treatment plant and services a population of approximately 3600 people. Four filter medium configurations were studied. Multi-media, dual-media, and single-media beds were constructed with the following media configurations: (1) coal-sand-garnet; (2) coal-sand; (3) sand-garnet; and (4) all sand. The filters were operated at two hydraulic loading rates. Effluents from the primary clarifier, trickling filter, and secondary clarifier were filtered to compare the difference in filter operation and performance when filtering different effluents. Wastewater quality parameters used to monitor filter performance were biochemical oxygen demand (BOD5) and suspended solids. The quality of filter influend affected the quality of the filter effluent. Typical total BOD5 and suspended soilds removal efficiencies were 30 percent and 75 percent, respectively. Soluble BOD5 was not significantly removed by granular filtration. The four filter beds were equally effective in removing suspended solids and biochemical oxygen demand. The coal layered filters operated for 22 hours maximum. The longest filter run time for the sand filters was 9 hours. Filtration of the Preston treatment facility effluent did not consistently produce and effluent that would satisfy the 10 mg/l BOD5 effluent discharge requirement. A survey conducted to review approbal criteria and design standards for wastewater filters employed by state regulatory agencies indicated the following. Most state standards allowed the installation of either gravity flow filters or pressure filters. The majority of state agencies base the allowable hydraulic loading rate on the type and configuration of media employed. The majority of the design standards for wastewater filters permitted the following media types: (1) sand; (2) anthracite; (3) sand and anthracite; (4) sand, anthracite, and garnet or ilmenite. All wastewater filter design standards called for backwast appurtenances complete with air scour or mechanical scour

Upgrading Aerated Lagoon Effluent with Intermittent Sand Filtration

Intermittent sand filtration was evaluated as a means of upgrading the quality of aerated lagoon effluents to satisfy the requirements of PL 92-500. The aerated lagoon in question treats the wastes from a milk and cheese factory located in northern Utah. The treatment system consists of two diffused air aeration ponds followed by a facultative settling pond, were applied to pilot scale intermittent sand filters with 0.17 mm and 0.40 mm effective size sands. The filters were loaded hydraulically from 0.25 million gallons per acre per day to 1.0 million gallons per acre per day. It was found that sand size has a profound effect on the quality of effluent produced by filtration. Also, sand size was related to the time of operation before plugging occurred. At the levels of application studied, hydraulic loading rate was found to affect BOD removal regardless of influent concentration. However, effluent suspended and volatile suspended solids concentrations reflected changes in influent concentrations regardless of hydraulic loading rate. It was found that filtration of facultative settling pond effluent provided better removals than direct filtration of aerated lagoon effluent using equivalent sand sixes and hydraulic loading rates. It was concluded that intermittent sand filtration was capable of upgrading the effluent from aerated lagoons to meet present and future discharge requirements when effluent from the facultative settling pond was applied to 0.17 mm effective size sand

A Continuous Flow Kinetic Model to Predict the Effects of Temperature on the Toxicity of Waste to Algae

A continuous flow kinetic model to describe and predict the effects of temperature on the toxicity of a specific oil refinery waste to the green alga

Bats of Skydusky Hollow, Bland County, Virginia

During the period 22 November 1999 – 11 October 2001, winter hibernacula surveys, spring staging/autumn swarming surveys, and summer surveys for bats were completed in caves of Skydusky Hollow, Bland County, Virginia. During winter, 12 caves were entered and 16,185 bats counted: 235 Myotis sodalis (Indiana bat), 14,475 Myotis lucifugus (little brown myotis), 12 Myotis septentrionalis (northern myotis), 7 Myotis leibii (eastern small-footed myotis), 1,441 Pipistrellus subflavus (eastern pipistrelle), and 15 Eptesicus fuscus (big brown bat). Myotis sodalis hibernated in thermally stable areas of 7 -9 ̊C. The largest concentration of M. lucifugus (n = 4,280) hibernated in an area that was cooler (6.5 ̊C) than areas used by M. sodalis. The remaining 6,300 M. lucifugus hibernated at temperatures similar to, or slightly cooler than, temperatures used by M. sodalis. Intra-cave (and possibly inter-cave) movements of M. lucifugus and M. sodalis during the season of hibernation concentrated bats in cooler areas of the caves. An unusually large concentration of P. subflavus (n = 920) hibernated in Coon Cave in a warm (8.6 – 9.7 ̊C, stable environment. Proportions of species of bats captured during spring staging and autumn swarming varied from proportions found during winter hibernation. Mating and perhaps other social functions affect patterns of autumn use. No concentration of bats used the caves during summer

Effects of Temperature on the Toxicity to the Aquatic Biota of Waste Discharges - A Compilation of the Literature

An extensive compiliation and general evaluation of the literature is presented which describes the temperature interaction with toxicity. Recent literature is summarized and made accessible along with a few generalized relationships such that researchers may design studies in a manner that will increase the utility of their results. A detailed indexing system is employed which makes the information contained in the report accessible by author, toxicant, and text organism. Summary tables of the most pertinent literature are also presented for easy subject retrieval. It was concluded that very little uniformity in experimental design is found between experiments on temperature-toxicity relationships, and a generalized summary of the results presented in th eliterature is essentially impossible because of the inconsistencies in experimental designs. The utilization of standard bioassay procedures is highly recommened, and these procedures should be applied to experimental designs which allow the estimation of parameters related to the theoretical effects of temperature

Design, Development, and Flight Evaluation of Pilot Displays and Long-Track Control for Wake Surfing Applications

These slides are the companion to the paper on the ACT experiment flown using a G-III autopilot and ADS-B datalink

Review paper: Evaluation of Techniques for Algae Removal from Wastewater Stabilization Ponds

Introduction: Approximately 90 percent of the wastewater lagoons in the United States are located in small communities of 5,000 people or less. These communities, many with an average daily wastewater flow of only 175,000 - 200,000 gallons, do not have the resources to keep man at the lagoon sites throughout the day (38). A high degree of technical knowhow is usually lacking in these communities. Often only periodic inspection or maintenance is carried out by the general municipal work force. Therefore, the development of a relatively inexpensive method that does not require sophisticated and constant operation or extensive maintenance is needed to polish these effluents. Most regulatory agencies are adopting more stringent water quality standards, enforcement of which will necessitate changes in present treatment methods and the philosophy of wastewater treatment. Small communities utilizing stabilization ponds will be affected most drastically by new standards. Because most communities utilizing ponds are relatively small and installed ponds primariliy to avoid operating costs, it is unlikely that modifications requiring significant increases in operation will be acceptable. Therefore, the most sophisticated alternatives for upgrading treatment must be excluded from a practicable solution to solids removal from stabilization pond effluent