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381.
Enhanced removal of heavy metals in primary treatment using coagulation and flocculation. 总被引:1,自引:0,他引:1
Pauline D Johnson Padmanabhan Girinathannair Kurt N Ohlinger Stephen Ritchie Leah Teuber Jason Kirby 《Water environment research》2008,80(5):472-479
The goal of this study was to determine the removal efficiencies of chromium, copper, lead, nickel, and zinc from raw wastewater by chemically enhanced primary treatment (CEPT) and to attain a total suspended solids removal goal of 80%. Operating parameters and chemical doses were optimized by bench-scale tests. Locally obtained raw wastewater samples were spiked with heavy metal solutions to obtain representative concentrations of metals in wastewater. Jar tests were conducted to compare the metals removal efficiencies of the chemical treatment options using ferric chloride, alum, and anionic polymer. The results obtained were compared with those from other studies. It was concluded that CEPT using ferric chloride and anionic polymer is more effective than CEPT using alum for metals removal. The CEPT dosing of 40 mg/L ferric chloride and 0.5 mg/L polymer enhanced heavy metals removal efficiencies by over 200% for chromium, copper, zinc, and nickel and 475% for lead, compared with traditional primary treatment. Efficient metals capture during CEPT can result in increased allowable headworks loadings or lower metal levels in the outfall. 相似文献
382.
Gonullu MT Avsar Y Apaydin O Bayhan H Kurt U 《Environmental monitoring and assessment》2006,121(1-3):559-567
Golden Horn is an estuary in Istanbul. It has connection with Marmara Sea directly and with Black Sea via Bosphorus, and was polluted by different kinds of industrial plants up to 1999. In addition to this, municipal wastewater of around one million people has been discharged to here. Greater part of the estuary was almost blocked off by sediment islands. Extensive effort was spent to dredge sediment in 1999. This created quite a convenient condition for aquatic medium in the estuary.In this research, the variations of chemical compositions of sediment bed were investigated to get clue about ecological conditions of the estuary. For that purpose, sediment samples were taken from 6 stations along the estuary in 2001, 2003 and 2004. The sediment samples were analyzed for inorganic and organic constituents. Meanwhile, water samples (from the surface and just above benthic mass) were also taken from the same 6 places and they were analyzed to verify the data from sediment samples. By this way, correlations between sediment mass and water body were determined. 相似文献
383.
384.
Perceptions of Species Abundance,Distribution, and Diversity: Lessons from Four Decades of Sampling on a Government-Managed Reserve 总被引:2,自引:0,他引:2
J. Whitfield Gibbons
Author to whom correspondence should be addressed. Vincent J. Burke Jeffrey E. Lovich Raymond D. Semlitsch Tracey D. Tuberville J. Russell Bodie Judith L. Greene Peter H. Niewiarowski Howard H. Whiteman David E. Scott Joseph H. K. Pechmann Christopher R. Harrison Stephen H. Bennett John D. Krenz Mark S. Mills Kurt A. Buhlmann John R. Lee Richard A. Seigel Anton D. Tucker Tony M. Mills Trip Lamb Michael E. Dorcas Justin D. Congdon Michael H. Smith David H. Nelson M. Barbara Dietsch Hugh G. Hanlin Jeannine A. Ott Deno J. Karapatakis 《Environmental management》1997,21(2):259-268
/ We examined data relative to species abundance, distribution, anddiversity patterns of reptiles and amphibians to determine how perceptionschange over time and with level of sampling effort. Location data werecompiled on more than one million individual captures or observations of 98species during a 44-year study period on the US Department of Energy's(DOE) Savannah River Site National Environmental Research Park (SRS-NERP) inSouth Carolina. We suggest that perceptions of herpetofaunal speciesdiversity are strongly dependent on level of effort and that land managementdecisions based on short-term data bases for some faunal groups could resultin serious errors in environmental management. We provide evidence thatacquiring information on biodiversity distribution patterns is compatiblewith multiyear spatially extensive research programs and also provide aperspective of what might be achieved if long-term, coordinated researchefforts were instituted nationwide.To conduct biotic surveys on government-managed lands, we recommend revisionsin the methods used by government agencies to acquire and report biodiversitydata. We suggest that government and industry employees engaged inbiodiversity survey efforts develop proficiency in field identification forone or more major taxonomic groups and be encouraged to measure the status ofpopulations quantitatively with consistent and reliable methodologies. Wealso suggest that widespread academic cooperation in the dissemination ofinformation on regional patterns of biodiversity could result byestablishment of a peer-reviewed, scientifically rigorous journal concernedwith status and trends of the biota of the United States. KEY WORDS: Abundance; Amphibian; Biodiversity; Distribution; Landmanagement; Reptile 相似文献
385.
Gönüllü MT Avşar Y Bayhan H Sakar S Arslankaya E Apaydin O Kurt U 《Environmental monitoring and assessment》2005,109(1-3):57-64
The shores of the Golden Horn—once most important seaport of the region—represented throughout history a romantic and recreational
venue. This tributary to the Bosphorus, however, became seriously polluted with the extensive industrialization and rapid
population growth in Istanbul over the past century. Two main tributaries, the Alibeykoy and the Kagithane, dumped both liquid
and solid waste from residential areas and industry (small and large-scale) into the Golden Horn. As a result of this pollution,
the landward three to four kilometers of the estuary became swamped with sediment. The dominance of anaerobic activity resulted
in a highly unpleasant smell, and the shallow depth as one progressed up the bay restricted navigation. In early 1997 The
Istanbul Metropolitan Municipality began a dredging operation and gradually diverted all domestic and industrial wastewater
discharge from the Golden Horn. Since then there have been remarkable improvements in water quality.
This paper presents the state of eutrophication through the water body of the Golden Horn; parameters such as DO, TKN, NH3-N, NO3-N, the total phosphorus (TP) and dissolved phosphorus (PO4-P), phytoplankton and chlorophyll-a have been were analyzed in samples of water taken from various points in the Golden Horn. The presence of DO and the phytoplankton,
both indicators of primary productivity in an aquatic body, has been evaluated in relation to former conditions. 相似文献
386.
In the spring of 1989, an experimental study of the spawning behaviour of Calanus finmarchicus was carried out in Malangen, northern Norway. Here, a single cohort of females reproduce from mid-March to May, approximately coinciding with the wax and wane of the spring phytoplankton bloom. An evaluation of population characteristics such as the proportion of adults, sex ratio, as well as gonad maturation and daily productivity of the females clearly reveals three phases within the population's reproductive period. In between incline and decline, the highest spawning rates (on average >20 eggs female-1 d-1, equivalent to 5.7% body C d-1) occur after the males have disappeared from the population and almost all females have mature gonads. During this period, the ratio of adults to copepodid Stage Vs changes from dominance of adults to that of CVs. Although first egg production was observed prior to the phytoplankton increase, it is suggested that the onset of the phytoplankton spring bloom in the first few days of April enhances the final maturation of ovaries in the females and therefore triggers the onset of the main spawning period. The clutch sizes (max. 95 eggs clutch-1) vary with the age of the females, while the spawning frequencies depend on the available food quantities. The overlap of an estimated minimal 4 wk spawning period for the individuals leads to a main reproductive phase for the population of ca. 3 wk, during which time mean clutch sizes and spawning frequencies are maximal (highest average clutch size: 70 eggs female-1 clutch-1, 100 to 60% of the females spawning). This period ends before the end of the phytoplankton bloom. Calculated by stepwise interpolation and summation of the mean daily egg production in the population, an average female produced ca. 600 eggs during the spring bloom in Malangen 1989. We suggest that reproduction and population development of C. finmarchicus in spring follows a reproducible pattern for a given temperature regime and non-limiting food conditions. In the case of clearly identifiable cohorts, it seems possible to trace the state of reproduction by evaluating population parameters. 相似文献
387.
388.
Kurt Noack 《Die Naturwissenschaften》1926,14(18):383-389
389.
390.