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      The Characterization of Feces and Urine: A Review of the Literature to Inform Advanced Treatment Technology

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          Abstract

          The safe disposal of human excreta is of paramount importance for the health and welfare of populations living in low income countries as well as the prevention of pollution to the surrounding environment. On-site sanitation (OSS) systems are the most numerous means of treating excreta in low income countries, these facilities aim at treating human waste at source and can provide a hygienic and affordable method of waste disposal. However, current OSS systems need improvement and require further research and development. Development of OSS facilities that treat excreta at, or close to, its source require knowledge of the waste stream entering the system. Data regarding the generation rate and the chemical and physical composition of fresh feces and urine was collected from the medical literature as well as the treatability sector. The data were summarized and statistical analysis was used to quantify the major factors that were a significant cause of variability. The impact of this data on biological processes, thermal processes, physical separators, and chemical processes was then assessed. Results showed that the median fecal wet mass production was 128 g/cap/day, with a median dry mass of 29 g/cap/day. Fecal output in healthy individuals was 1.20 defecations per 24 hr period and the main factor affecting fecal mass was the fiber intake of the population. Fecal wet mass values were increased by a factor of 2 in low income countries (high fiber intakes) in comparison to values found in high income countries (low fiber intakes). Feces had a median pH of 6.64 and were composed of 74.6% water. Bacterial biomass is the major component (25–54% of dry solids) of the organic fraction of the feces. Undigested carbohydrate, fiber, protein, and fat comprise the remainder and the amounts depend on diet and diarrhea prevalence in the population. The inorganic component of the feces is primarily undigested dietary elements that also depend on dietary supply. Median urine generation rates were 1.42 L/cap/day with a dry solids content of 59 g/cap/day. Variation in the volume and composition of urine is caused by differences in physical exertion, environmental conditions, as well as water, salt, and high protein intakes. Urine has a pH 6.2 and contains the largest fractions of nitrogen, phosphorus, and potassium released from the body. The urinary excretion of nitrogen was significant (10.98 g/cap/day) with urea the most predominant constituent making up over 50% of total organic solids. The dietary intake of food and fluid is the major cause of variation in both the fecal and urine composition and these variables should always be considered if the generation rate, physical, and chemical composition of feces and urine is to be accurately predicted.

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          Impact of pyrolysis temperature and manure source on physicochemical characteristics of biochar.

          While pyrolysis of livestock manures generates nutrient-rich biochars with potential agronomic uses, studies are needed to clarify biochar properties across manure varieties under similar controlled conditions. This paper reports selected physicochemical results for five manure-based biochars pyrolyzed at 350 and 700°C: swine separated-solids; paved-feedlot manure; dairy manure; poultry litter; and turkey litter. Elemental and FTIR analyses of these alkaline biochars demonstrated variations and similarities in physicochemical characteristics. The FTIR spectra were similar for (1) turkey and poultry and (2) feedlot and dairy, but were distinct for swine biochars. Dairy biochars contained the greatest volatile matter, C, and energy content and lowest ash, N, and S contents. Swine biochars had the greatest P, N, and S contents alongside the lowest pH and EC values. Poultry litter biochars exhibited the greatest EC values. With the greatest ash contents, turkey litter biochars had the greatest biochar mass recoveries, whereas feedlot biochars demonstrated the lowest. Published by Elsevier Ltd.
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            Converting nitrogen into protein--beyond 6.25 and Jones' factors.

            The protein content in foodstuffs is estimated by multiplying the determined nitrogen content by a nitrogen-to-protein conversion factor. Jones' factors for a series of foodstuffs, including 6.25 as the standard, default conversion factor, have now been used for 75 years. This review provides a brief history of these factors and their underlying paradigm, with an insight into what is meant by "protein." We also review other compelling data on specific conversion factors which may have been overlooked. On the one hand, when 6.25 is used irrespective of the foodstuff, "protein" is simply nitrogen expressed using a different unit and says little about protein (s.s.). On the other hand, conversion factors specific to foodstuffs, such as those provided by Jones, are scientifically flawed. However, the nitrogen:protein ratio does vary according to the foodstuff considered. Therefore, from a scientific point of view, it would be reasonable not to apply current specific factors any longer, but they have continued to be used because scientists fear opening the Pandora's box. But because conversion factors are critical to enabling the simple conversion of determined nitrogen values into protein values and thus accurately evaluating the quantity and the quality of protein in foodstuffs, we propose a set of specific conversion factors for different foodstuffs, together with a default conversion factor (5.6). This would be far more accurate and scientifically sound, and preferable when specifically expressing nitrogen as protein. These factors are of particular importance when "protein" basically means "amino acids," this being the principal nutritional viewpoint.
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              Epidemiology of constipation in North America: a systematic review.

              The aim of this study was to systematically review the published literature regarding prevalence, risk factors, incidence, natural history, and the effect on quality of life of constipation in North America. A computer-assisted search of MEDLINE, EMBASE, and Current Contents databases was performed independently by two investigators. Study selection criteria included the following: (1) North American population-based sample of adults with constipation; (2) publication in full manuscript form in English; and (3) report on the prevalence, incidence, and natural history of constipation or impact of constipation on quality of life. Eligible articles were reviewed in a duplicate, independent manner. Data extracted were compiled in tables and presented in descriptive form. The estimates of the prevalence of constipation in North America ranged from 1.9% to 27.2%, with most estimates from 12% to 19%. Prevalence estimates by gender support a female-to-male ratio of 2.2:1. Constipation appears to increase with increasing age, particularly after age 65. No true population-based incidence studies or natural history studies were identified. In one cohort, 89% of patients with constipation still reported constipation at 14.7 months follow-up. From limited data, quality of life appears to be diminished by constipation, but the clinical significance of this is unclear. Constipation is very common, as approximately 63 million people in North America meet the Rome II criteria for constipation. Minimal data are available regarding incidence, natural history, and quality of life in patients with constipation. Effort should be expended toward the study of these topics, particularly in the elderly, who are disproportionately affected by this condition.
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                Author and article information

                Journal
                Crit Rev Environ Sci Technol
                Crit Rev Environ Sci Technol
                BEST
                best20
                Critical Reviews in Environmental Science and Technology
                Taylor & Francis
                1064-3389
                1547-6537
                2 September 2015
                29 May 2015
                : 45
                : 17
                : 1827-1879
                Affiliations
                [ a ]Cranfield Water Science Institute, Cranfield University , Cranfield, Bedfordshire, United Kingdom
                Author notes
                Address correspondence to A. Parker, Cranfield Water Science Institute, Cranfield University , Cranfield, Bedfordshire MK43 0AL, United Kingdom. E-mail: a.parker@ 123456cranfield.ac.uk
                Article
                1000761
                10.1080/10643389.2014.1000761
                4500995
                26246784
                396903ae-7bc6-4225-8abb-aa4724f8219e
                © 2015 The Author(s). Published with license by Taylor & Francis© C. Rose, A. Parker, B. Jefferson, E. Cartmell

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The moral rights of the named author(s) have been asserted.

                History
                Page count
                Figures: 6, Tables: 12, References: 236, Pages: 53
                Categories
                Original Articles

                General environmental science
                fecal characteristics,feces,feces treatment,human excreta,urine,urine characteristics

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