Patrick Brezonik - Academia.edu (original) (raw)

Papers by Patrick Brezonik

Journal of The American Water Resources Association, Dec 1, 1982

Journal of The American Water Resources Association, Apr 1, 1982

Water Air and Soil Pollution, Feb 1, 1985

Removal of nutrients from wastewater (effluent) by sediments in cypress swamps was studied in lab... more Removal of nutrients from wastewater (effluent) by sediments in cypress swamps was studied in laboratory leaching columns filled with wet surface sediments. Columns were leached with low-nutrient groundwater, treated wastewater, and treated wastewater amended with nitrate (20 to 30 mg N L-1) and phosphate (9.5 mg P L-1) for 21 too. From 99 to 100% of the nitrate-nitrite and P was removed from the amended wastewater eluants throughout the investigation; average concentrations of nitrate-nitrite and P in effluent from amended wastewater columns did not exceed concentrations in leachate from columns eluted with groundwater. Ammonium removal was approximately 50~ in columns receiving treated wastewater. Sediments of cypress swamps have a large capacity to remove nutrients from secondary effluent.

Water Research, Apr 1, 2002

Urban nonpoint source pollution is a significant contributor to water quality degradation. Waters... more Urban nonpoint source pollution is a significant contributor to water quality degradation. Watershed planners need to be able to estimate nonpoint source loads to lakes and streams if they are to plan effective management strategies. To meet this need for the twin cities metropolitan area, a large database of urban and suburban runoff data was compiled. Stormwater runoff loads and concentrations of 10 common constituents (six N and P forms, TSS, VSS, COD, Pb) were characterized, and effects of season and land use were analyzed. Relationships between runoff variables and storm and watershed characteristics were examined. The best regression equation to predict runoff volume for rain events was based on rainfall amount, drainage area, and percent impervious area (R 2 ¼ 0:78). Median event-mean concentrations (EMCs) tended to be higher in snowmelt runoff than in rainfall runoff, and significant seasonal differences were found in yields (kg/ha) and EMCs for most constituents. Simple correlations between explanatory variables and stormwater loads and EMCs were weak. Rainfall amount and intensity and drainage area were the most important variables in multiple linear regression models to predict event loads, but uncertainty was high in models developed with the pooled data set. The most accurate models for EMCs generally were found when sites were grouped according to common land use and size.

The Minnesota WRRI program is administered by the University of Minnesota Water Resources Center ... more The Minnesota WRRI program is administered by the University of Minnesota Water Resources Center (WRC), which is a collaborative enterprise involving several college-level units: the College of Natural Resources (CNR), College of Agricultural, Food & Environmental Sciences (COAFES), and the Minnesota Extension Service (MES), plus the University of Minnesota Graduate School, which provides funds to administer the Water Resources Science graduate program, which is housed administratively in the WRC. The WRC has co-directors, who divide the overall responsibilities for Center operations between them. Patrick Brezonik reports to the dean of CNR and is responsible for administering the WRRI program. He also is Director of Graduate Studies for the WRS Program. James L. Anderson reports to the deans of COAFES and MES and is responsible for extension operations. The co-directors share responsibilities for other outreach and research activities of the Center.

In this presentation I will provide an overview of program activities and funding opportunities f... more In this presentation I will provide an overview of program activities and funding opportunities for water research and education at NSF, focusing on (1) cross-cutting (inter-directorate) initiatives and (2) opportunities in the primary engineering and hydrologic science programs that fund water resources research. I also will present my perspectives regarding future trends in research and funding based on my experiences as program director for Environmental Engineering for the past three years. One important trend is the development of national-scale environmental observatory networks, such as NEON and WATERS Network, which will be cyber-enabled systems for large-scale interdisciplinary environmental studies. I will briefly describe these initiatives and how they are expected to transform the ways that research and education in environmental engineering and the hydrologic sciences will be done in the future

Water, Air, and Soil Pollution, 1985

Environmental Management, 1984

... (N)I = kn(1 - Rn(m))/qs = (m)i(] - Rn(m) ) (2) or (m)l/(m)/= (1 - Rn(m)) (3) where (N)i and (... more ... (N)I = kn(1 - Rn(m))/qs = (m)i(] - Rn(m) ) (2) or (m)l/(m)/= (1 - Rn(m)) (3) where (N)i and (N)I are the analogous average influent and in-lake concentrations of TN and Rn(m) is the measured nitrogen retention coefficient (= [Nin - Nout]/Nin ). ...

Journal of the Sanitary Engineering Division, Aug 1, 1969

Journal of the Sanitary Engineering Division, Dec 1, 1971

A series of experiments were performed with laboratory scale activated sludge units to determine ... more A series of experiments were performed with laboratory scale activated sludge units to determine the effects of various environmental conditions on the ATP content of activated sludge mixed liquor. ATP was determined by the firefly luciferin-luciferase reaction. The effect of abrupt temperature changes up to about 37°C was small. Anoxia reduced the ATP content by about 40%, but an immediate return to the original level was noted when sludge was reaerated. Complex patterns of ATP response were found for substrate (milk solids) additions and for additions of various inorganic toxicants. ATP responses to toxic heavy metals are rapid and sensitive, and ATP appears to be a good measure of sludge viability and activity.

Water, Air, & Soil Pollution, 1986

A large data base on inland lakes in the Upper Great Lakes Region (UGLR) was used to evaluate ass... more A large data base on inland lakes in the Upper Great Lakes Region (UGLR) was used to evaluate assumptions and relationships of empirical acidification models. Improved methods to calculate background alkalinity and background S042-are reported; SO42-enrichment factors indicate that terrestrial S042-sources and watershed or lake sinks must be considered for site-specific backgound S042-estimates. Significant relationships were found between lake acidification estimated as change in S042-and precipitation acidity but not between changes in lake alkalinity and precipitation acidity in this lightly impacted region.

Limnology and Oceanography, 1980

The nitrogenous organic matter from two freshwater lakes and from the filtrate of a unialgal cult... more The nitrogenous organic matter from two freshwater lakes and from the filtrate of a unialgal culture of Anabaena sp. was characterized chemically and evaluated for metal complexation ability. Proteinaceous matter was isolated from acidified samples by cellulose cation exchange columns and eluted with a basic salt solution. Isolated proteinaceous matter accounted for 14–34% of the original dissolved organic nitrogen. Gel permeation chromatography and ultrafiltration methods used to separate dissolved organic nitrogen into various size fractions yielded differing results, but most of the organic nitrogen had apparent molecular weights between 10,000 and 50,000 daltons. The copper‐complexing capacity of the proteinaceous matter was determined by differential pulse anodic stripping voltammetry. Conditional stability constants, which represent the mixed stability of all nonlabile ligands in the sample, ranged from 1.6 × 106 to 1.3 × 107 for the three samples.

JAWRA Journal of the American Water Resources Association, 1980

ABSTRACT: Direct measurements indicate that subsurface seepage in the littoral zone contributed 1... more ABSTRACT: Direct measurements indicate that subsurface seepage in the littoral zone contributed 17.5 and 2.0 percent of the total hydraulic inputs, respectively, to Lakes Conway and Apopka, Florida. Two variations of seepage measuring devices were evaluated and gave relative standard deviations of 7 and 24 percent. Measurement inaccuracies were minimized by using large diameter (0.9 cm ID) plastic tubing. For a given transect perpendicular to shore, flow patterns were reproducible over time. Seepage flows ranged from 0 to 112 1/m2‐day and most were between 4 and 30 1/m2‐day. The detection limit was about 0.2 1/m2‐day for a one‐hour collection period. Seepage occured primarily within 30 m of shore and generally decreased exponentially with distance from shore. The shape of the bottom profile influenced flow patterns; lake bottoms with steeper slopes had higher flows that were compressed within a narrower zone. After a short‐term rain event at Lake Conway, seepage flows increased rapi...

Nutrient loading rates were estimated for Anderson-Cue Lake in Florida. The lake was artificially... more Nutrient loading rates were estimated for Anderson-Cue Lake in Florida. The lake was artificially spiked with phosphorus. Nutrient budgets for the lake and other lakes were compared. Nutrient sources and sinks for lakes were identified. A partial nutrient budget for Anderson-Cue lake was prepared, and the chemical composition of the lake's water was compared to rainwater. 5 tables.

Proceedings, 1990

SynopsisIn experiments lakes 223 (L223) and 302 South (L302S) in the Experimental Lakes Area in n... more SynopsisIn experiments lakes 223 (L223) and 302 South (L302S) in the Experimental Lakes Area in north-western Ontario, and Little Rock Lake (LRL) in northern Wisconsin, were progressively acidified with sulphuric acid from original pH values of 6.1–6.8 to 4.7–5.1. Although the lakes were at different locations with different physical settings and assemblages of plants and animals including fish, there were remarkable similarities in their responses, particularly in regard to biogeochemical processes and effects on biota at lower trophic levels.All three lakes generated an important part of their buffering capacity internally b\ the reduction of sulphate, and to a lesser extent by the reduction of nitrate. Alkalinity production increased as concentrations of biologically-active strong acid anions increased. Models relating the residence times of sulphate and nitrate to water renewal, or first-order kinetics, effectively predicted events.Acidification disrupted nitrogen cycling in all three lakes. Nitrification was inhibited in L223 and L302S, while in LRL, nitrogen fixation was greatly decreased at low pH.The phytoplankton communities of all three lakes were originally dominated by chrysophyceans and cryptophyceans. However acidification changed the dominant species and decreased diversity. Acidification tended to increase phytoplankton production and standing crop slightly, probably because light penetration was increased.Littoral zones of all three lakes became increasingly dominated by a few species of filamentous green algae, which created nuisance blooms by pH 5.6. Mats or clouds of algae changed the entire character of the littoral zone.Acidification of L223 and L302S caused the loss of several species of large benthic crustaceans as pH changed from 6 to 5.6. Large, acid-sensitive littoral crustaceans were absent from LRL before acidification, probably because the lake was already too acidic.As acidity increased, the dominance of cladocerans within zooplankton communities increased.Daphnia catawbaappeared at pH values near 5.6 and became more abundant at lower pHs as the lakes were acidified. Its appearance coincided with a decline in otherDaphniaspecies: another cladoceran,Bosmina longirostris, increased in the experimentally-acidified lakes as didKeratella taurocephala: they became the dominant rotifers. Several sensitive zooplankton species declined or disappeared as the lakes were acidified, most notablyDaphnia galeata mendotae, Epischura lacustris, Diaptomus sicilisandKeratella cochlearis.The responses of different fish varied; they appeared to depend on the sensitivity of key organisms in the food chain. The ability of key fish species to reproduce was impaired as early as pH 5.8; their reproduction, except for yellow perch in LRL, had ceased at pH 5.0 in all the three lakes.Acidification consistently reduced the diversity and richness of species in taxonomic groups studied, these effects resulting from losses of species and the increased dominance of a few acidophilic taxa.Responses of experimentally-acidified lakes in north-western Ontario and atmospherically-acidified lakes in eastern Ontario were similar in most respects where records allowed comparisons to be made, notably in relation to biogeochemical processes and the disappearance of acid-sensitive biota.When the acidification of L223 was reversed, several biotic components recovered quickly. Fish resumed reproduction at pHs similar to those at which it ceased when the lake was being acidified. The condition of lake trout improved as a result of greatly increased populations of small fish, their prey. Many species of insects and crustaceans that had been extirpated by acidification returned. Assemblages of phytoplankton and chironomids have retained an acidophilic character, although their diversity during recovery is similar to that at comparable pHs during progressive acidification. As their chemistry recovered, atmospherically-acidified lakes in the Sudbury area were able to sustain recruitment by species offish, including lake trout and white sucker, with rapid increases in the diversity of invertebrate taxa. Results from both L223 and lakes near Sudbury suggest a rapid partial recovery of lacustrine communities when acidification is reversed.It is concluded that the experimental lakes responded similarly to acidification, and that experimental acidification can reliably indicate the effects of acidification attributable to acidic precipitation.

CRC Press eBooks, Nov 25, 2020