Suspended solids in combined sewer flows

Many studies have identified the first flush phenomenon as being the relatively high concentration of pollutants in the initial phases of combined sewer flow following a storm. One way of controlling the first flush is by the provision of a storage tank such that the effluent can be discharged in a controlled manner. To optimise the storage volume, both the total pollutant load discharged and the temporal variation in pollutant concentration within an event need to be predicted. Sophisticated models to predict the pollutant concentrations in urban sewer flows, for example QSIM and MOUSETRAP are already available. However, the data requirements for these models are extensive, which usually limit their application to major or environmentally sensitive schemes. This paper describes attempts to relate the peak concentration of suspended solids in combined sewer flows to observed storm characteristics. In this study, it was hypothesised that the peak concentrations of suspended solids could be related to the hydrological parameters of maximum rainfall intensity, storm duration, and antecedent dry weather period prior to the storm which are commonly used as the basic parameters for urban sewer design. Data from two sites at Great Harwood and Clayton-le-Moors in the North-west of England has been used in the study and an attempt has been made to define an upper limit of the first flush concentration of suspended solids corresponding to storms which have been categorised into bands defined by their peak rainfall intensity.

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The Upwelling in the Region between Java and Australia during the South-East Monsoon

Marine and Freshwater Research ◽

10.1071/mf9620217 ◽

1962 ◽

Vol 13 (3) ◽

pp. 217 ◽

Cited By ~ 75

Author(s):

K Wyrtki

Keyword(s):

Monsoon Season ◽

The South ◽

High Concentration ◽

North West ◽

The North ◽

Plankton Biomass ◽

Equatorial Current ◽

High Concentrations ◽

West Monsoon ◽

Upwelling Area

An examination of the oceanographic conditions in the region between Java and Australia during the south-east monsoon season shows that the main upwelling area in this region is situated along the coast of Java and Sumbawa, and not along the north-west Australian shelf, as was previously assumed. The amount of upwelling south of Java is estimated to contribute 2.4 million m3/sec to the South Equatorial Current and the upwelling velocity is of the order of 50 × 10-5 cm/sec. The region is characterized by very high concentrations of inorganic phosphate at the bottom of the euphotic layer and by a high plankton biomass. The transparency of the water in the upwelling area is low, indicating a high concentration of suspended matter. The possible development of the upwelling during the north-west monsoon season is discussed.

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Aspects of forage bushland rereclamation in the North-West of Russia

Кормопроизводство ◽

10.25685/krm.2019.2019.36013 ◽

2019 ◽

Author(s):

А. Иванов ◽

Ж. Иванова ◽

И. Соколов ◽

И. Петров ◽

А. Кудрявцев

Keyword(s):

Fertility Restoration ◽

Poultry Manure ◽

Crop Productivity ◽

Wood Products ◽

Perennial Grasses ◽

High Concentration ◽

Land Quality ◽

North West ◽

The North ◽

Annual Grasses

Земельная реформа на СевероЗападе России привела к выводу из использования значительной части сельскохозяйственных угодий. В отсутствие надлежащего мелиоративного ухода они быстро зарастают древеснокустарниковой растительностью (ДКР). На фоне увеличения потребности в высококачественных кормах возникла острая необходимость освоения закустаренных залежных земель. Целью комплексного исследования стала оценка воздействия новых технологических приёмов переработки древесины и воспроизводства почвенного плодородия на продуктивность и качество зелёной массы однолетних и многолетних трав. Методической основой исследования служил мелкоделяночный полевой опыт в звене полевого севооборота однолетние травы с подсевом многолетних трав многолетние травы . Опыт был заложен в 2017 году на базе ООО София на залежных землях Тосненской низины Ленинградской области. Почва дерновоподзолистая глееватая тяжелосуглинистая с сильнокислой реакцией среды (рНKCl 4,27), средней обеспеченностью подвижным фосфором и повышенной концентрацией обменного калия. Схема опыта двухфакторная. Фактор А продукты переработки ДКР: щепа (5 15 см) продукт фрезерной обработки машинами импортного производства в дозе 100 т/га, сечка (1 5 см) продукт переработки мульчерами в дозе 100 т/га, биоуголь продукт пиролизной переработки ДКР в дозе 10 т/га и древесная зола (1,05 т/га). Фактор Б новая система воспроизводства плодородия (НСВП) на основе комплекса химических мелиорантов: птичьего помёта в дозах 20 и 40 т/га, сыромолотого доломита в дозе 10 т/га и калийного удобрения (K70 и K140). При заделке в почву предварительно переработанной ДКР происходило резкое уменьшение урожайности и значительное снижение качественных показателей кормовой продукции первой сельскохозяйственной культуры. Только при сочетании прогрессивных мелиоративных технологий с комплексом химических мелиорантов была достигнута высокая агрономическая эффективность освоения закустаренной залежи. Это обеспечило повышение продуктивности звена севооборота в среднем на 42, а в вариантах с биоуглем на 54. При этом валовой сбор сырого протеина возрастал на 64 и 85 соответственно. Его содержание в контрольном варианте составило 1,50 т/га, а в вариантах с ДКР и НСВП 1,29 и 2,46 т/га соответственно. This investigation studied the effect of wood products applied into soil on grass productivity and green mass quality. The crop rotation included: annual grasses and overseeding with perennial crops perennial grasses. Microplot trial took place on the old Tosna river lowland in 2017 on the base of OOO Sofiya. Sodpodzolic gleyic soil had high amount of clay, рНKCl of 4.27, medium content of soluble P and high concentration of exchange K. Experimental design twofactorial. Factor A wood product: chips (5 15 cm) 100 t ha1, waste (1 5 cm) 100 t ha1, biochar 10 t ha1 and ash 1.05 t ha1. Factor B new fertility restoration system complex of chemical ameliorants: poultry manure (20 and 40 t ha1), row grinded dolomite (10 t ha1) and potassium fertilizers (K70 and K140). Wood products applied into soil sharply decreased forage quality and productivity of the first crop. Combination of modern cultivation technologies and chemicals effectively improved land quality. Crop productivity increased by 42, under the biochar treatment by 54. Gross yield of crude protein rose by 64 and 85, respectively. Its content amounted to 1.50 t ha1 in the control, 1.29 and 2.46 t ha1 for factors A and B, respectively.

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Characterization and first flush analysis in road and roof runoff in Shenyang, China

Water Science & Technology ◽

10.2166/wst.2014.203 ◽

2014 ◽

Vol 70 (3) ◽

pp. 397-406 ◽

Cited By ~ 10

Author(s):

Chunlin Li ◽

Miao Liu ◽

Yuanman Hu ◽

Jiping Gong ◽

Fengyun Sun ◽

...

Keyword(s):

Heavy Metals ◽

Rainfall Intensity ◽

Urban Runoff ◽

First Flush ◽

Roof Runoff ◽

Maximum Rainfall ◽

Rainfall Duration ◽

Pearson's R ◽

Mean Concentration ◽

Pearson’S R

As urbanization increases, urban runoff is an increasingly important component of total urban non-point source pollution. In this study, the properties of urban runoff were examined in Shenyang, in northeastern China. Runoff samples from a tiled roof, a concrete roof and a main road were analyzed for key pollutants (total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), chemical oxygen demand (COD), Pb, Cd, Cr, Cu, Ni, and Zn). The event mean concentration, site mean concentration, M(V) curves (dimensionless cumulative curve of pollutant load with runoff volume), and mass first flush ratio (MFF30) were used to analyze the characteristics of pollutant discharge and first flush (FF) effect. For all events, the pollutant concentration peaks occurred in the first half-hour after the runoff appeared and preceded the flow peaks. TN is the main pollutant in roof runoff. TSS, TN, TP, Pb, and Cr are the main pollutants in road runoff in Shenyang. There was a significant correlation between TSS and other pollutants except TN in runoff, which illustrated that TSS was an important carrier of organic matter and heavy metals. TN had strong positive correlations with total rainfall (Pearson's r = 0.927), average rainfall (Pearson's r = 0.995), and maximum rainfall intensity (Pearson's r = 0.991). TP had a strong correlation with rainfall intensity (Pearson's r = 0.940). A significant positive correlation between COD and rainfall duration (Pearson's r = 0.902, significance level = 0.05) was found. The order of FF intensity in different surfaces was concrete roof > tile roof > road. Rainfall duration and the length of the antecedent dry period were positively correlated with the FF. TN tended to exhibit strong flush for some events. Heavy metals showed a substantially stronger FF than other pollutant.

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Rainfall Intensity-Duration-Frequency Relationships for Risk Analysis in the Region of Matopiba, Brazil

Revista Brasileira de Meteorologia ◽

10.1590/0102-77863340239 ◽

2019 ◽

Vol 34 (2) ◽

pp. 247-254

Author(s):

Luciele Vaz da Silva ◽

Derblai Casaroli ◽

Adão Wagner Pêgo Evangelista ◽

José Alves Júnior ◽

Rafael Battisti

Keyword(s):

Rainfall Intensity ◽

Frequency Function ◽

Annual Rainfall ◽

Frequency Model ◽

Maximum Rainfall ◽

Rainfall Duration ◽

The North ◽

Gumbel Model ◽

Intensity Duration Frequency ◽

Agricultural Areas

Abstract The region of study was MATOPIBA, located in the north of Brazilian Savanna biome (Cerrado), encompassing part of north/northeast of Brazil. The region has been gaining prominence in the last years due to the expansion of agricultural over this area. The aims of this study were: to adjust parameters for rainfall intensity-duration-frequency; and to identify the most vulnerable agricultural areas to erosion based on erosivity and erodibility. The rainfall intensity-duration-frequency function were adjusted using series of maximum annual rainfall event from 105 rainfall gauges. Gumbel model was the most efficient to simulate the maximum rainfall intensity, where these data were used to adjusted the rainfall intensity-duration-frequency model based on K, a, b and c parameters. The most rainfall gauges showed intensity between 51 and 80 mm h-1 and 81 and 120 mm h-1, respectively, for return period of 2 and 100 years with rainfall duration of 30 minutes. The higher rainfall intensity was observed mainly in the central-north of the region associated with rainfall systems. The rainfall intensity showed a huge capacity to cause soil erosion based on the erosivity energy, while the moderate erodibility was observed for areas with Ferralsols and Leptosols and low erodibility for areas with Arenosols.

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An improved Victorian erosivity map

Soil Research ◽

10.1071/sr02030 ◽

2003 ◽

Vol 41 (1) ◽

pp. 141 ◽

Cited By ~ 12

Author(s):

G. J. Sheridan ◽

C. J. Rosewell

Keyword(s):

Rainfall Intensity ◽

Soil Surface ◽

Water Runoff ◽

Contour Map ◽

North West ◽

Erosion Processes ◽

The North ◽

Forested Areas ◽

The Individual ◽

The Impact

The impact of raindrops on the soil surface and surface water runoff are two of the agents of soil detachment and sediment transport. The magnitude of these erosion processes is a function of the erosive potential, or erosivity of a rainstorm. The erosivity of rainfall is commonly quantified using the R factor developed for the universal soil loss equation. R is the average of the annual sum of the individual storm erosivity values and can be estimated from published relationships between the storm energy and the rainfall intensity. Currently the most likely source of R-values in Victoria is a hand-drawn contour map produced more than 20 years ago by an expert panel and published in an out-of-print handbook. A new R-value contour map for Victoria is presented, developed from current empirical relationships between rainfall intensity–frequency–duration and R. The R contours vary in value across the state by about a factor of 4, from <800 MJ.mm/ha.h.year in the north-west, to >2700 MJ.mm/ha.h.year in the eastern ranges. The new map improves the resolution and accuracy of erosivity values for Victoria, especially in steeper, forested areas, and will assist in the prediction and modelling of erosion and water quality.

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Morphometric Analysis of Pluto’s Impact Craters

Remote Sensing ◽

10.3390/rs13030377 ◽

2021 ◽

Vol 13 (3) ◽

pp. 377

Author(s):

Caio Vidaurre Nassif Villaça ◽

Alvaro Penteado Crósta ◽

Carlos Henrique Grohmann

Keyword(s):

Morphometric Analysis ◽

Target Surface ◽

Impact Craters ◽

Morphometric Data ◽

High Concentration ◽

Software Environment ◽

North West ◽

The North ◽

The Difference ◽

The Impact

The scope of this work is to carry out a morphometric analysis of Pluto’s impact craters. A global Pluto digital elevation model (DEM) with a resolution of 300 m/px, created from stereoscopic pairs obtained by the New Horizons Mission, was used to extract the morphometric data of craters. Pluto’s surface was divided according to different morphometric characteristics in order to analyze possible differences in the impact dynamics and modification rate in each region. A Python code was developed, within the QGIS 3× software environment, to automate the process of crater outlining and collection of morphometric data: diameter (D), depth (d), depth variation, slope of the inner wall (Sw), diameter of the base (Db), and the width of the wall (Ww). Data have been successfully obtained for 237 impact craters on five distinct terrains over the west side of Sputnik Planitia on Pluto. With the collected data, it was possible to observe that craters near the equator (areas 3 and 4) are deeper than craters above 35°N (areas 1 and 2). Craters on the western regions (areas 2 and 3) contain the lowest depth values for a given diameter. The transition diameter from simple to complex crater morphology was found to change throughout the areas of study. Craters within areas 1 and 4 exhibit a transition diameter (Dt) of approximately 10 km, while Dt for craters within areas 3 and 5 the transitions occurs at 15 km approximately. The presence of volatile ices in the north and north-west regions may be the reason for the difference of morphometry between these two terrains of Pluto. Two hypotheses are presented to explain these differences: (1) The presence of volatile ices can affect the formation of craters by making the target surface weaker and more susceptible to major changes (e.g., mass waste and collapse of the walls) during the formation process until its final stage; (2) The high concentration of volatiles can affect the depth of the craters by atmospheric decantation, considering that these elements undergo seasonal decantation and sublimation cycles.

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SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157838 ◽

1990 ◽

Vol 48 (3) ◽

pp. 58-59

Author(s):

Daryl A. Cornish ◽

George L. Smit

Keyword(s):

Morphological Characteristics ◽

Oreochromis Mossambicus ◽

Breeding Cycle ◽

Limited Information ◽

North West ◽

The North ◽

Sem And Tem ◽

Sperm Development ◽

Ultrastructural Characteristics ◽

The University

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.

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