scholarly journals Spray Irrigation of Citrus Waste

Author(s):  
Henry P. Morrell

Land application of wastewater is an old practice — it was used by the Greeks in Athens and was begun in the United States over 100 years ago. Hundreds of communities throughout the nation currently use one form or another of land application with varying degrees of success. The application of wastewater to the land brings into play elements of climate, air, land, irrigation and water so that understanding and analysis of its many aspects requires a multi-disciplinary approach. There are three generally accepted approaches to land application. These are: 1. Irrigation 2. Overland Flow 3. Infiltration Percolation Paper published with permission.

1994 ◽  
Vol 2 (1) ◽  
pp. 108-118 ◽  
Author(s):  
S. P. McGrath ◽  
A. C. Chang ◽  
A. L. Page ◽  
E. Witter

Heavy metals in sewage sludges accumulate in soils after successive sludge applications and can be toxic to plants, soil organisms, as well as humans and animals along the food chain. Because of this potential threat, many countries have set limits to the additions of metals in sludges to agricultural land, based on (i) the concentrations of metals in sludge itself, (ii) the loading, or total amount, of metal that can be added and often how quickly this can be applied, and (iii) the maximum concentrations of metals in soil which are allowed to build up after sludge applications. This review, based on regulations in the United States and some west European countries, shows that at present three basic approaches to setting limits can be distinguished: (i) a comprehensive analysis of the pathways of pollutant transfer to selected target organisms and an assessment of the likely harmful effects that metals may have on the target; (ii) setting limits consistent with the lowest observed adverse effect concentrations, which are actual cases of effects due to metals, but not necessarily derived from studies that involved land application of sewage sludge; and (iii) attempting to match the metal inputs to soil to the small losses of metals due to crop removal, soil erosion, and leaching ("metal balance approach"). These approaches are shown to result in widely different numerical limits being set for the same constituent, which is creating unease among the regulatory authorities worldwide. These differences appear to arise from at least two main sources. The first is whether, by a policy decision, zero impact is desired. This leads to very low limits, and is the philosophy behind the metal balance approach. The second is that those approaches that allow some increase in metal concentrations in soils often adopt different target organisms and these models suffer from the limited supply of relevant toxicity data, particularly information obtained from metals applied in sewage sludge. Differences in the philosophy behind environmental protection and in the choices of which organisms to protect explain the different metal limits for sewage sludge which have been adopted in the countries examined.Key words: zinc, cadmium, copper, chromium, nickel, lead, mercury, soil microbes, ecotoxicology, soil protection.


2017 ◽  
Vol 25 (4) ◽  
pp. 452-462 ◽  
Author(s):  
Anne T. Pollard ◽  
Matthew J. Morra

In 2012 there were 63% fewer dairies in the United States than there were in 1997 as a result of conglomeration of the dairy industry into concentrated animal feeding operations at the expense of smaller farms. Today, 60% of all milk produced in the United States comes from 5% of the nation’s dairies (operations with ≥ 500 cows). Concentrated animal feeding operations are touted as economically efficient agricultural business models, hailed for their increased milk yields. Yet, with an average daily manure production of over 27 000 kg for a 500-head dairy farm, manure storage and disposal are serious management and environmental concerns. A common economical mode of manure disposal is application to nearby agricultural fields. However, a major concern with land application of dairy manure is the fate of manure-borne hormones, compounds considered chemicals of emerging concern, and the potential threat these hormones pose to humans and the environment. The fate of these chemicals in the soil environment is complicated by multiple edaphic variables including pH, mineralogy, organic matter, microbial activity, and redox status. Estrogens are sorbed by soil organic matter and transformed to nonbioactive, highly soluble conjugated forms or to metabolites that exhibit yet additional properties distinct from their parent compounds. However, deconjugation frequently occurs, regenerating endocrine-disrupting free estrogen compounds. It is challenging to fully understand the behavior and predict the fate of estrogenic compounds from dairy manure in soils because of variable and complex interactions with soil factors, as well as possible interactions among the different chemicals of emerging concern. This review focuses on the behavior of naturally occurring estrogen hormones present in dairy manure in the soil environment. Heightened understanding of the fate of these compounds in soil will enhance our ability to reduce their potential risks.


Author(s):  
David L. Lewis ◽  
David K. Gattie ◽  
Marc E. Novak ◽  
Susan Sanchez ◽  
Charles Pumphrey

Fertilization of land with processed sewage sludges, which often contain low levels of pathogens, endotoxins, and trace amounts of industrial and household chemicals, has become common practice in Western Europe, the United States, and Canada. Local governments, however, are increasingly restricting or banning the practice in response to residents reporting adverse health effects. These self-reported illnesses have not been studied and methods for assessing exposures of residential communities to contaminants from processed sewage sludges need to be developed. Methods: To describe and document adverse effects reported by residents, 48 individuals at ten sites in the United States and Canada were questioned about their environmental exposures and symptoms. Information was obtained on five additional cases where an outbreak of staphylococcal infections occurred near a land application site in Robesonia, Pennsylvania. Medical records were reviewed in cases involving hospitalization or other medical treatment. Since most complaints were associated with airborne contaminants, an air dispersion model was used as a means for potentially ruling out exposure to sludge as the cause of adverse effects. Results: Affected residents lived within approximately 1 km of land-application sites and generally complained of irritation (e.g., skin rashes and burning of the eyes, throat, and lungs) after exposure to winds blowing from treated fields. A prevalence of Staphylococcus aureus infections of the skin and respiratory tract was found. Approximately one in four of 54 individuals were infected, including two mortalities (septicemia, pneumonia). This result was consistent with the prevalence of S. aureus infections accompanying diaper rashes in which the organism, which is occasionally found in the lower human colon, tends to invade irritated or inflamed tissue. Conclusions: When assessing public health risks from applying sewage sludges in residential areas, potential interactions of chemical contaminants with low levels of pathogens should be considered. An increased risk of infection may occur when allergic and non-allergic reactions to endotoxins and other chemical components irritate skin and mucous membranes and thereby compromise normal barriers to infection.


2021 ◽  
Vol 13 (7) ◽  
pp. 3263-3279
Author(s):  
Jun Zhang ◽  
Laura E. Condon ◽  
Hoang Tran ◽  
Reed M. Maxwell

Abstract. Topography is a fundamental input to hydrologic models critical for generating realistic streamflow networks as well as infiltration and groundwater flow. Although there exist several national topographic datasets for the United States, they may not be compatible with gridded models that require hydrologically consistent digital elevation models (DEMs). Here, we present a national topographic dataset developed to support gridded hydrologic simulations at 1 km and 250 m spatial resolution over the contiguous United States. The workflow is described step by step in two parts: (a) DEM processing using a Priority Flood algorithm to ensure hydrologically consistent drainage networks and (b) slope calculation and smoothing to improve drainage performance. The accuracy of the derived stream network is evaluated by comparing the derived drainage area to drainage areas reported by the national stream gage network. The slope smoothing steps are evaluated using the runoff simulations with an integrated hydrologic model. Our DEM product started from the National Water Model DEM to ensure our final datasets will be as consistent as possible with this existing national framework. Our analysis shows that the additional processing we provide improves the consistency of simulated drainage areas and the runoff simulations that simulate gridded overland flow (as opposed to a network routing scheme). The workflow uses an open-source R package, and all output datasets and processing scripts are available and fully documented. All of the output datasets and scripts for processing are published through CyVerse at 250 m and 1 km resolution. The DOI link for the dataset is https://doi.org/10.25739/e1ps-qy48 (Zhang and Condon, 2020).


Author(s):  
Robert C. Hale ◽  
Mark J. La Guardia

Land application has become the dominant means for sewage sludge disposal in the United States. In 1993, the EPA concluded that synthetic organics therein posed an insignificant risk, based on the results of the 1988 National Sewage Sludge Survey, the view that most persistent organics are no longer in commerce and that industrial pretreatment further reduces their release to municipal treatment plants. However, we detected high concentrations of several problematic compounds in biosolids that were overlooked in the risk assessment, including persistent, bioaccumulative polybrominated diphenyl ethers and estrogenic nonylphenols. These results and other findings call into question the assessment's certainty.


Author(s):  
A. Hakam ◽  
J.T. Gau ◽  
M.L. Grove ◽  
B.A. Evans ◽  
M. Shuman ◽  
...  

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.


Author(s):  
Vinod K. Berry ◽  
Xiao Zhang

In recent years it became apparent that we needed to improve productivity and efficiency in the Microscopy Laboratories in GE Plastics. It was realized that digital image acquisition, archiving, processing, analysis, and transmission over a network would be the best way to achieve this goal. Also, the capabilities of quantitative image analysis, image transmission etc. available with this approach would help us to increase our efficiency. Although the advantages of digital image acquisition, processing, archiving, etc. have been described and are being practiced in many SEM, laboratories, they have not been generally applied in microscopy laboratories (TEM, Optical, SEM and others) and impact on increased productivity has not been yet exploited as well.In order to attain our objective we have acquired a SEMICAPS imaging workstation for each of the GE Plastic sites in the United States. We have integrated the workstation with the microscopes and their peripherals as shown in Figure 1.


2001 ◽  
Vol 15 (01) ◽  
pp. 53-87 ◽  
Author(s):  
Andrew Rehfeld

Every ten years, the United States “constructs” itself politically. On a decennial basis, U.S. Congressional districts are quite literally drawn, physically constructing political representation in the House of Representatives on the basis of where one lives. Why does the United States do it this way? What justifies domicile as the sole criteria of constituency construction? These are the questions raised in this article. Contrary to many contemporary understandings of representation at the founding, I argue that there were no principled reasons for using domicile as the method of organizing for political representation. Even in 1787, the Congressional district was expected to be far too large to map onto existing communities of interest. Instead, territory should be understood as forming a habit of mind for the founders, even while it was necessary to achieve other democratic aims of representative government.


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