scholarly journals Sediment-associated organic matter sources and sediment oxygen demand in a Special Area of Conservation (SAC): A case study of the River Axe, UK

2017 ◽  
Vol 33 (10) ◽  
pp. 1539-1552 ◽  
Author(s):  
A. L. Collins ◽  
Y. Zhang ◽  
S. McMillan ◽  
E. R. Dixon ◽  
A. Stringfellow ◽  
...  
Water ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 159 ◽  
Author(s):  
Guoyu Xu ◽  
Xiaodong Ren ◽  
Zhenhua Yang ◽  
Haifei Long ◽  
Jie Xiao

Water quality is highly influenced by the composition and configuration of landscape structure, and regulated by various spatiotemporal factors. Using the Wujiang river watershed as a case study, this research assesses the influence of landscape metrics—including composition and spatial configuration—on river water quality. An understanding of the relationship between landscape metrics and water quality can be used to improve water contamination predictability and provide restoration and management strategies. For this study, eight water quality variables were collected from 32 sampling sites from 2014 through 2017. Water quality variables included nutrient pollutant indicators ammoniacal nitrogen (NH3-N), nitrogen (NO3−), and total phosphate (TP), as well as oxygen-consuming organic matter indicators COD (chemical oxygen demand), biochemical oxygen demand (BOD5), dissolved oxygen (DO), and potassium permanganate index (CODMn). Partial least squares (PLS) regression was used to quantitatively analyze the influence of landscape metrics on water quality at five buffer zone scales (extending 3, 6, 9, 12, and 15 km from the sample site) in the Wujiang river watershed. Results revealed that water quality is affected by landscape composition, landscape configuration, and precipitation. During the dry season, landscape metrics at both landscape and class levels predicted organic matter at the five buffer zone scales. During the wet season, only class-level landscape metrics predicted water contaminants, including organic matter and nutrients, at the middle three of five buffer scales. We identified the following important indicators of water quality degradation: percent of landscape, edge density, and aggregation index for built-up land; aggregation index for water; CONTAGION; COHESION; and landscape shape index. These results suggest that pollution can be mitigated by reducing natural landscape composition fragmentation, increasing the connectedness of region rivers, and minimizing human disturbance of landscape structures in the watershed area.


2016 ◽  
Vol 16 (3) ◽  
pp. 141-146
Author(s):  
Daria Mimier ◽  
Janusz Żbikowski

Abstract The main objective of this study was to characterize the muddy bottom sediments of three hydrologically different old river beds of the lower Vistula, located in the vicinity of Toruń: Port Drzewny, Martwa Wisła and Przybysz. Samples were taken at monthly intervals from April to November 2015 from two (Martwa Wisła and Przybysz) or three sampling sites (Port Drzewny) located in the central parts of the reservoirs. The bottom sediments of these water bodies were characterized by a low water content and organic matter content expressed as a percentage of dry weight, high organic matter content expressed in units of weight, as well as a high sediment oxygen demand. The most distinct reservoir was Martwa Wisła, most likely due to the lack of a connection with the River Vistula.


1995 ◽  
Vol 46 (1) ◽  
pp. 81 ◽  
Author(s):  
RK Gelda ◽  
MT Auer ◽  
SW Effler

Rates of sediment oxygen demand (SOD) were determined for hypereutrophic Onondaga Lake, New York (USA), by direct and indirect means. The direct approach, laboratory measurements made on intact sediment cores, yielded an average SOD rate of 1.68�0.56 g O2 m-2 day-1. This was essentially equivalent to that determined indirectly by estimating the sediment flux of reduced chemical species (1 .64�0.14 g O2 m-2 day-1). Sulfide, methane, ammonia, and ferrous iron contributed 50, 42, 7, and <1% of the total sediment flux of reduced species, respectively. The sulfide percentage is unusually high for freshwater systems, reflecting the sulfate-rich nature of the lake. Variability in the sediment flux of reduced species over the 3-year study was modest (12%), and rates were consistent with those measured in other systems of similar trophic state. Rates of SOD closely approximated the areal hypolimnetic oxygen deficit of the lake. More than 70% of the SOD was explained by the oxidation of reduced chemical species. These findings suggest that recovery of the oxygen resources of the lake will be mediated primarily through reductions in the delivery of particulate organic matter to the sediments and the rate at which in-place reserves of particulate organic matter are stabilized. The processes of algal respiration and aerobic mineralization of organic matter in the water column, which exhibit a more rapid response to remediation measures, will play a lesser role.


2020 ◽  
Vol 21 (1) ◽  
pp. 86-94
Author(s):  
Andri Warsa ◽  
Lismining Pujiyani Astuti

ABSTRACTIr. H. Djuanda or Jatiluhur reservoir as a multifunction water body with one of utilization as fish cultivation activity. Uneaten feed and fish excretion were organic matter sources. The number of floating net cages was increasing and it caused increasing in organic matter load. The objective of the research was to known organic matter load and decomposition rate (k) and BOD (Biochemical oxygen demand) ultimate (Lo) at Jatiluhur Reservoir. The research was done in February and August 2018 at three locations were Astap, Pasir Canar and Pulau Aki. The result of the research shown was organic load from cultivation activity was 70,595 tons/year. The decomposition rate of organic matter around 0.10-0.25 per day with BOD ultimate around 6.80-8.11 mg/L. The value of Lo was affected by organic matter concentration.Keywords: Ir. H. Djuanda Reservoir, organic matter, decomposition rate, BOD ultimateABSTRAKWaduk Ir. H. Djuanda atau yang dikenal dengan Waduk Jatiluhur merupakan waduk multifungsi yang salah satu pemanfaatannya untuk kegiatan budidaya ikan. Sisa pakan yang terbuang dan ekresi ikan merupakan sumber masukkan bahan organik. Jumlah keramba jaring apung (KJA) yang semakin bertambah akan menyebabkan beban masukkan bahan organik meningkat. Tujuan penelitian ini adalah untuk mengetahui beban masukkan bahan organik dari kegiatan budidaya dan laju dekomposisi bahan organik (k) serta BOD (Biochemical oxygen demand) ultimate (Lo) di Waduk Jatiluhur. Penelitian dilakukan pada bulan Februari dan Agustus 2018 pada tiga lokasi yaitu Astap, Pasir Canar dan Pulau Aki. Pendekatan yang digunakan dalam penentuan nilai k dan Lo adalah metode Grafik Thomas. Hasil penelitian menunjukkan bahwa beban masukkan bahan organik dari kegiatan budidaya sebesar 70.595 ton/tahun. Beban masukkan bahan organik telah melebihi daya dukung perairan. Nilai k untuk dekomposisi bahan organik di Waduk Jatiluhur berkisar 0,10-0,25 per hari dengan nilai Lo berkisar 6,80-8,11 mg/L. Nilai Lo dipengaruhi oleh konsentrasi bahan organik di perairan.    Kata kunci: Waduk Ir. H. Djuanda, bahan organik, laju peluruhan, BOD ultimate 


2012 ◽  
Vol 7 (1) ◽  
Author(s):  
Yanjin Liu ◽  
Giraldo Eugenio

Cultured bacteria addition is one of the technologies used for odor control and FOG (fat, oil, and grease) removal in wastewater collection systems. This study investigated the efficiency of bacterial addition on wastewater odor control by conducting a set of full scale trials in a 60,000 cubic meter per day system for a period of two years. The objectives of this study were: (i) to identify factors that could impact wastewater treatment plant (WWTP) operations due to the effect of bacterial addition in the collection system, (ii) to estimate/understand the level of those impacts, and (iii) to present some interesting findings from the completed case study. The plant operation data before and during the bacterial addition were reviewed. The application of the cultured bacteria presented in the study was found to have significant impacts on the operation of the WWTP in terms of influent biological oxygen demand (BOD) and total suspended solids (TSS) loading, primary settling, sludge production, energy use, dissolved sulfides concentration, and methane production.


1998 ◽  
Vol 38 (10) ◽  
pp. 23-30
Author(s):  
Sarah Jubb ◽  
Philip Hulme ◽  
Ian Guymer ◽  
John Martin

This paper describes a preliminary investigation that identified factors important in the prediction of river water quality, especially regarding dissolved oxygen (DO) concentration. Intermittent discharges from combined sewer overflows (CSOs) within the sewerage, and overflows at water reclamation works (WRW) cause dynamic conditions with respect to both river hydraulics and water quality. The impact of such discharges has been investigated under both wet and dry weather flow conditions. Data collected from the River Maun, UK, has shown that an immediate, transient oxygen demand exists downstream of an outfall during storm conditions. The presence of a delayed oxygen demand has also been identified. With regard to modelling, initial investigations used a simplified channel and the Streeter-Phelps (1925) dissolved oxygen sag curve equation. Later, a model taking into account hydrodynamic, transport and dispersion processes was used. This suggested that processes other than water phase degradation of organic matter significantly affect the dissolved oxygen concentration downstream of the location of an intermittent discharge. It is proposed that the dynamic rate of reaeration and the sediment oxygen demand should be the focus of further investigation.


2000 ◽  
Vol 42 (3-4) ◽  
pp. 265-272 ◽  
Author(s):  
T. Inoue ◽  
Y. Nakamura ◽  
Y. Adachi

A dynamic model, which predicts non-steady variations in the sediment oxygen demand (SOD) and phosphate release rate, has been designed. This theoretical model consists of three diffusion equations with biochemical reactions for dissolved oxygen (DO), phosphate and ferrous iron. According to this model, step changes in the DO concentration and flow velocity produce drastic changes in the SOD and phosphate release rate within 10 minutes. The vigorous response of the SOD and phosphate release rate is caused by the difference in the time scale of diffusion in the water boundary layer and that of the biochemical reactions in the sediment. Secondly, a negative phosphate transfer from water to sediment can even occur under aerobic conditions. This is caused by the decrease in phosphate concentration in the aerobic layer due to adsorption.


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