E. Joe Middlebrooks

Arsenic and fluoride removal from groundwater by reverse osmosis

Abstract The reverse osmosis process was evaluated for removal of naturally occurring arsenic and fluoride from groundwater. Arsenic removal was affected by the prevalent arsenic species present in the water. Arsenic concentrations were reduced by approximately 60%–90% from nearly 80 μg/L. Fluoride concentrations were reduced by approximately 60% from nearly 1.7 mg/L.

Wastewater lagoon sludge characteristics

Abstract Biological and physical characteristics of four wastewater treatment lagoon sludges were investigated. The four lagoon sludges possessed total solids (TS), volatile solids (VS) and pH values within the range of values reported in the literature for primary sludges. The lagoon sludges VS concentrations were between 49 and 80%: relatively high values considering a possible sludge age of several months or years. In addition, heavy metal concentrations in the four lagoon sludges were reported.

Nitrogen removal in aerated lagoons

Abstract Rational and empirical models of ammonia nitrogen and total Kjeldahl nitrogen (TKN) removals were evaluated as a means of developing design relationships that can be used to estimate nitrogen removal in aerated wastewater lagoons. Plug flow, complete mix and dispersed flow hydraulic models were evaluated in conjunction with Monod growth kinetics, first order kinetics, and multiple substrate limiting relations. Polynomial equations, and multiple regression analyses were also tried. Combinations of the models were evaluated using field data from five aerated lagoon systems operating in various geographical areas of the USA. Only the plug flow model, assuming first order kinetics, of the classical approaches to biological modeling produced satisfactory results. Because of the simplicity of the plug flow model and a model based on the relationship between the fraction of nitrogen removed and the hydraulic detention time, it was recommended that these two equations be used to estimate nitrogen removal in aerated lagoons.

Indian creek reservoir sediments

Abstract Indian Creek Reservoir (ICR) was originally designed to hold the effluent from the South Tahoe Public Utility District (STPUD) advanced wastewater treatment plant during the winter months and to release the impounded water during the irrigation season. The original use of the reservoir has been modified extensively, and in addition to the agricultural uses, the reservoir has become a popular recreational facility. Changes in the use of the reservoir have resulted in changes in the standards imposed upon the STPUD and ICR. Because of the unique nature of the influent to ICR, unusual claims are frequently made about the characteristics of the water and sediments. The question is frequently asked if the sediments in ICR differ from those found in other eutrophic lakes or reservoirs. Sediment samples were collected from four diverse sites in the reservoir. The samples were analysed for phosphorus, carbon, nitrogen, volatile content, and chlorophyll content. The results of the analyses showed that the sediments are typical of those found in any eutrophic lake or reservoir.

Lime stabilization and land disposal of cold region wastewater lagoon sludge

Abstract Effects of lime [Ca(OH) 2 ] stabilization upon the pathogenic population in accumulated solids associated with the operation of two aerated wastewater lagoons in Alaska and two facultative wastewater lagoons in northern Utah were evaluated. The subsequent drying, at a temperature of 12 °C, of the lime stabilized sludges on sand and soil beds was also investigated. The lime stabilization of the lagoon sludges was evaluated by dosing the sludges with lime and applying sludges to bench scale drying beds. Lime addition produced high fecal coliform reduction, and the limed sludges readily dewatered on both sand and soil beds.