Total Suspended Solids Loads Research Articles

SEDIMENTASI DI DELTA SUNGAI CITARUM, KECAMATAN MUARA GEMBONG, KABUPATEN BEKASI (Sedimentation at delta of Citarum River, Muara Gembong District, Bekasi Regency)

One of land use change impacts in the downstream of Citarum watershed is sedimentation. This study aimed to determine the total suspended solid and sediment load in the downstream of Citarum River. The Total Suspended Solid ( TSS ) samples were taken in three locations: the inlet of Jatiluhur reservoir, the outlet of Jatiluhur reservoir, and before the Citarum River estuary. The frequency of TSS samplings was twice a year i.e during the dry season and the rainy season at 2014. Analysis of TSS content was in accordance with SNI 06-6989.3-2004 using gravimetry method. The results showed that TSS at down stream Citarum River flow was 0.44 kg/m 3 , TSS at the inlet of Jatiluhur reservoir was 0.20 kg/m 3 , and TSS at the outlet of Jatiluhur reservoir was 0.02kg/m 3 . The total sediment in the inlet of Jatiluhur was 1.34 x 10 6 ton/year, in the outlet of Jatiluhur reservoir was 0.14 x 10 6 ton/year, and the flow sediment total to the Citarum River estuary was 1.79 x 10 6 ton/year. The Jatiluhur reservoir could reduce the potential for sediment total flowing into the sea as much as 1.20x 10 6 tons/year. Area of sedimentation at the delta of Citarum River was 3,828.26 ha.

Influence of Cattle Trails on Runoff Quantity and Quality.

Cattle trails in grazed pastures close to rivers may adversely affect surface water quality of the adjacent river by directing runoff to it. The objective of this 3-yr study (2013-2015) in southern Alberta, Canada, was to determine if cattle trails significantly increased the risk of runoff and contaminants (sediment, nutrients) compared with the adjacent grazed pasture (control). A portable rainfall simulator was used to generate artificial rainfall (140 mm h) and runoff. The runoff properties measured were time to runoff and initial abstraction (infiltration), total runoff depth and average runoff rates, as well as concentrations and mass loads of sediment, N, and P fractions. Cattle trails significantly ( ≤ 0.10) decreased time to runoff and initial abstraction (26-32%) in the 2 yr measured and increased total runoff depth, runoff coefficients, and average runoff rates (21-51%) in 2 of 3 yr. Concentrations of sediment, N, and P fractions in runoff were not significantly greater for cattle trails than for control areas. However, mass loads of total suspended solids (57-85% increase), NH-N (31-90%), and dissolved reactive P (DRP) (30-92%) were significantly greater because of increased runoff volumes. Overall, runoff quantity and loads of sediment, NH-N, and DRP were greater for cattle trails compared with the adjacent grazed pasture, and hydrologic connection with cattle-access sites on the riverbank suggests that this could adversely affect water quality in the adjacent river. Extrapolation of the study results should be tempered by the specific conditions represented by this rainfall simulation study.

Characterisation of water quality in effluents of land-based abalone farms in the Western Cape, South Africa

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 9:87-102 (2017) - DOI: https://doi.org/10.3354/aei00217 Characterisation of water quality in effluents of land-based abalone farms in the Western Cape, South Africa T. A. Probyn1,*, M. Pretorius2, K. Seanego1, A. Bernatzeder2 1Aquaculture Research and 2Sustainable Aquaculture Management, Department of Agriculture, Forestry and Fisheries, Private Bag X2, Vlaeberg 8018, Cape Town, South Africa *Corresponding author: trevorp@daff.gov.za ABSTRACT: Effluent water quality was measured at 9 abalone (Haliotis midae) farms in 2 regional nodes (west and south) along the South African coastline. For most farms, effluent total suspended solids (TSS) exceeded the background reference level (80th percentile), and 3 did not comply with the 5 mg l-1 standard. Total ammonia nitrogen (NH4+) concentrations were mostly greater than reference levels but well below the 43 µmol N l-1 standard. Inflow-corrected concentrations of nitrate, nitrite and phosphate were low compared to NH4+ and would not pose a significant eutrophication risk. Similarly, the biochemical oxygen demand measured at 3 of the farms was low (median 1.31 mg l-1). Abalone production-specific annual loads of TSS (334 kg per metric tonne [mt]), total N (20.3-38.1 kg N mt-1) and total P (3.2-7.5 kg P mt-1) agree with what has been found for different land-based aquaculture operations. These figures translate to N-based human population equivalents of 5.4-10.6 persons mt-1 for both regions. At the broader ecosystem level, the annual TSS loads calculated from 2013 production data of 43 mt yr-1 (west) and 369 mt yr-1 (south) are, respectively, 0.35 and 2.8% of that estimated for kelp erosion. Similarly, the dissolved inorganic N loads of 1.9 mt N yr-1 (west) and 9.4 mt yr-1 (south) are trivial by comparison with nitrate advected during upwelling. Local abalone farms have a relatively high specific C footprint—conservatively ~44 kg CO2 kg-1 production. Our findings support a relatively low potential impact of farm effluents in this coastal upwelling environment. KEY WORDS: Abalone farm · Effluents · Suspended solids · Nutrients · Haliotis Full text in pdf format PreviousNextCite this article as: Probyn TA, Pretorius M, Seanego K, Bernatzeder A (2017) Characterisation of water quality in effluents of land-based abalone farms in the Western Cape, South Africa. Aquacult Environ Interact 9:87-102. https://doi.org/10.3354/aei00217 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 9. Online publication date: February 21, 2017 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2017 Inter-Research.

Field campaign on sediment transport behaviour in a pressure main from pumping station to wastewater treatment plant in Berlin.

As part of the project KURAS, the Berliner Wasserbetriebe realized a field campaign in 2015 in order to increase the process knowledge regarding the behaviour of transported sediment in the pressure main leading from the pumpstation to the wastewater treatment plant. The field campaign was conducted because of a lack of knowledge about the general condition of the pressure main due to its bad accessibility and the suspicion of deposits caused by hydraulic underload. The practical evidence of the sediment transport performance of this part of the sewer system, dependent on different load cases, should present a basis for further analysis, for example regarding flushing measures. A positive side-effect of the investigation was the description of the amount of pollutants caused by different weather conditions in combined sewer systems and the alterations of the sewage composition due to biogenic processes during transport. The concept included the parallel sampling of the inflow at the pumpstation and the outflow at the end of the pressure main during different weather conditions. By calculating the inflow to the pressure main, as well as its outflow at different flow conditions, it was possible to draw conclusions in regard to the transport behaviour of sediment and the bioprocesses within an 8.5 km section of the pressure main. The results show clearly that the effects of sedimentation and remobilization depend on the flow conditions. The balance of the total suspended solids (TSS) load during daily variations in dry weather shows that the remobilization effect during the run-off peak is not able to compensate for the period of sedimentation happening during the low flow at night. Based on the data for dry weather, an average of 238 kg of TSS deposits in the pressure main remains per day. The remobilization of sediment occurs only due to the abruptly increased delivery rates caused by precipitation events. These high pollution loads lead to a sudden strain at the wastewater treatment plant. It was found that the sediment transport behaviour is characterized by sedimentation up to a flow velocity of 0.35 m/s, while remobilization effects occur above 0.5 m/s. The assumption of bad sediment transport performance in the pressure main was confirmed. Therefore, the results can be used as a basis for further analysis, for example regarding periodical flushing as a means of cleaning the pressure main. The findings, especially regarding the methods and processes, are transferable and can be applied to other pressure mains in combined sewer systems. Besides the outlined evaluation of the sediment transport behaviour of the pressure main, the collected data were used in the project to calibrate a sewer system model, including a water quality model for the catchment area, and as a contribution towards an early physically based sediment transport modelling in InfoWorks CS.

Study on the Effect of Variation of Flow in Sequencing Batch Reactor Using PCA and ANOVA

Wastewater treatment using Sequencing Batch Reactor (SBR) technology is one of the state-of-the art wastewater management systems. In this technology equalization, biological treatment and secondary clarification are performed in a single reactor in a time control sequence. SBR system is idler for the areas where the available land is limited, since it operates in less space and very cost effective even on small scales. The control of the operational parameters during the process of biological wastewater treatment is often complicated due to the dynamic change in the composition and characteristics of the raw wastewater, flow rates and other parameters influencing the complex nature of the treatment process and the process in SBR has a unique cyclic batch operation. The performance of the SBR was studied using pilot and real plant at Puducherry. The parameters considered in this study are flow, Mixed Liquor Suspended Solids (MLSS), pH, temperature, influent and effluent of Total Suspended Solids (TSS), Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD). As a part of the study, the effect of constant flow and varying flow on the organic loading of the influent TSS, BOD and COD and their influence on the organic load of the effluent parameters were examined to identify the level of significance of the parameters in relation to the flow. The impact of flow on other parameters was also examined. The experimental data obtained from pilot and real plants were analyzed using multi variate statistical analyses like correlation analysis, Principal Component Analysis (PCA) and Analysis of variance (ANOVA). The statistical analysis revealed that constant flow had no significant role and the influent parameters alone had the critical role, whereas varying flow as well as the influent parameters had the significant role on the performance of SBR.

Sediment and nutrient budgets are inherently dynamic: evidence from a long-term study of two subtropical reservoirs

Abstract. Accurate reservoir budgets are important for understanding regional fluxes of sediment and nutrients. Here we present a comprehensive budget of sediment (based on total suspended solids, TSS), total nitrogen (TN) and total phosphorus (TP) for two subtropical reservoirs on rivers with highly intermittent flow regimes. The budget is completed from July 1997 to June 2011 on the Somerset and Wivenhoe reservoirs in southeast Queensland, Australia, using a combination of monitoring data and catchment model predictions. A major flood in January 2011 accounted for more than half of the water entering and leaving both reservoirs in that year, and approximately 30 % of water delivered to and released from Wivenhoe over the 14-year study period. The flood accounted for an even larger proportion of total TSS and nutrient loads: in Wivenhoe more than one-third of TSS inputs and two-thirds of TSS outputs between 1997 and 2011 occurred during January 2011. During non-flood years, mean historical concentrations provided reasonable estimates of TSS and nutrient loads leaving the reservoirs. Calculating loads from historical mean TSS and TP concentrations during January 2011, however, would have substantially underestimated outputs over the entire study period, by up to a factor of 10. The results have important implications for sediment and nutrient budgets in catchments with highly episodic flow. First, quantifying inputs and outputs during major floods is essential for producing reliable long-term budgets. Second, sediment and nutrient budgets are dynamic, not static. Characterizing uncertainty and variability is therefore just as important for meaningful reservoir budgets as accurate quantification of loads.

Effectiveness of Livestock Exclusion in a Pasture of Central North Carolina.

Reducing the export of nitrogen (N), phosphorus (P), and sediment from agricultural land in water-supply watersheds is a continuing goal in central North Carolina. The objective of this project was to document the effectiveness of a combination of livestock exclusion fencing and nutrient management implemented on a beef cattle pasture located in the Piedmont region of North Carolina. The quantity and quality of discharge from two predominantly pasture watersheds were monitored simultaneously for 3.8 yr before and after implementation of the exclusion fencing and nutrient management in the treatment watershed; a control watershed remained unchanged. The excluded stream corridor was intentionally minimized by constructing the fence line about 3 m from the top of the streambank on either side and limiting it to the main stream channel only. Monitoring included collecting flow-proportional samples during storm events and analyzing them for total Kjeldahl N (TKN), ammonia (NH-N), and inorganic (NO-N) N as well as total P (TP) and total suspended solids (TSS). Statistically significant reductions were observed in TKN (34%), NH-N (54%), TP (47%), and TSS (60%) loads in the treatment relative to the control watershed after fencing, whereas storm discharge and NO-N loads were not significantly different. These data show that even a relatively narrow exclusion corridor implemented on only the main stream channel can significantly reduce the export of N, P, and sediment from a beef cattle pasture.

Floating faeces: Effects on solid removal and particle size distribution in RAS

The removal of solid wastes originating from faecal matter is one of the decisive challenges for future fish farming, in particular given the current emphasis on water reuse in aquaculture. This study compared solid waste removal performance in replicate recirculating systems in which the only difference was the removal concept being deployed. Rainbow trout (Oncorhynchus mykiss) of the test group were fed an innovative diet supplemented with 2.5% cork granules (0.5–1mm) resulting in buoyant faecal casts (density values below 1.00gcm−3). These were removed directly from the tank by a low cost slotted pipe at the water surface. The control group was fed a conventional diet, identical to the experimental feed except that it lacked the cork additive. The resulting solids in both systems were removed by sedimentation in a classic manure pit, which was drained to the drum filter twice a day. Wastewater from both treatments was mechanically cleaned by a drum filter and biologically treated by a moving bed bioreactor before being returned to the tanks.The cork treatment led to a substantially higher solid load being delivered to the drum filter via the wastewater outflow than in the control system. The average removal efficiency of cork-treated wastes was more than twice that achieved in the control system (59% vs. 25%). Total suspended solid (TSS) in the backwash stream of the drum filter was about five times greater in the cork diet treatment. There was no significant difference in the particle size distribution or TSS load of water passing the 100μm gauze of the drum filter in the two systems. Cork supplementation did not affect growth or mortality of rainbow trout. The present study shows that the application of floating faeces is an exciting prospect in recirculating aquaculture systems, offering significant improvements in solid removal efficiency.

Assessing cost-effectiveness of bioretention on stormwater in response to climate change and urbanization for future scenarios

Bioretention,as a popular low impact development practice,has become more important to mitigate adverse impacts on urban stormwater. However, there is very limited information regarding ensuring the effectiveness of bioretention response to uncertain future challenges, especially when takinginto considerationclimate change and urbanization. The main objective of this paper isto identify the cost-effectiveness of bioretention by assessing the hydrology performance under future scenarios modeling. First, the hydrology model was used to obtain peak runoff and TSS loads of bioretention with variable scales under different scenarios,i.e., different Representative Concentration Pathways (RCPs) and Shared Socio-economic reference Pathways (SSPs) for 2-year and 10-year design storms in Singapore. Then, life cycle costing (LCC) and life cycle assessment (LCA) were estimated for bioretention, and the cost-effectiveness was identified under different scenarios. Our finding showed that there were different degree of responses to 2-year and 10-year design storms but the general patterns and insights deduced were similar. The performance of bioretenion was more sensitive to urbanization than that for climate change in the urban catchment. In addition, it was noted that the methodology used in this study was generic and the findings could be useful as reference for other LID practices in response to climate change and urbanization.

A spatially distributed model for assessment of the effects of changing land use and climate on urban stream quality

AbstractWhile the effects of land use change in urban areas have been widely examined, the combined effects of climate and land use change on the quality of urban and urbanizing streams have received much less attention. We describe a modelling framework that is applicable to the evaluation of potential changes in urban water quality and associated hydrologic changes in response to ongoing climate and landscape alteration. The grid‐based spatially distributed model, Distributed Hydrology Soil Vegetation Model‐Water Quality (DHSVM‐WQ), is an outgrowth of DHSVM that incorporates modules for assessing hydrology and water quality in urbanized watersheds at a high‐spatial and high‐temporal resolution. DHSVM‐WQ simulates surface run‐off quality and in‐stream processes that control the transport of non‐point source pollutants into urban streams. We configure DHSVM‐WQ for three partially urbanized catchments in the Puget Sound region to evaluate the water quality responses to current conditions and projected changes in climate and/or land use over the next century. Here, we focus on total suspended solids (TSS) and total phosphorus (TP) from non‐point sources (run‐off), as well as stream temperature. The projection of future land use is characterized by a combination of densification in existing urban or partially urban areas and expansion of the urban footprint. The climate change scenarios consist of individual and concurrent changes in temperature and precipitation. Future precipitation is projected to increase in winter and decrease in summer, while future temperature is projected to increase throughout the year. Our results show that urbanization has a much greater effect than climate change on both the magnitude and seasonal variability of streamflow, TSS and TP loads largely because of substantially increased streamflow and particularly winter flow peaks. Water temperature is more sensitive to climate warming scenarios than to urbanization and precipitation changes. Future urbanization and climate change together are predicted to significantly increase annual mean streamflow (up to 55%), water temperature (up to 1.9 °C), TSS load (up to 182%) and TP load (up to 74%). Copyright © 2016 John Wiley & Sons, Ltd.

Stormwater Pollutant Process Analysis with Long-Term Online Monitoring Data at Micro-Scale Sites

Stormwater runoff quality was measured with online turbidity sensors at four common types of small urban subcatchments: (i) a flat roof; (ii) a parking lot; (iii) a residential catchment; and (iv) a high-traffic street. Samples were taken to estimate site-specific correlations between total suspended solids (TSS) and turbidity. Continuous TSS time series were derived from online turbidity measurements and were used to estimate event loads and event mean concentrations. Rainfall runoff event characteristics were subjected to correlation analysis to TSS loads. Significant correlations were found for rainfall intensities at sites with high imperviousness and decrease with increasing catchment size. Antecedent dry weather periods are only correlated at the parking lot site. Intra-event TSS load distributions were studied with M (V)-curves. M (V)-curves are grouped at runoff quantiles and statistically described with boxplots. All sites show, in general, a more pronounced first-flush effect. While wash-off of the flat roof tends to be source-limited, the parking lot and high-traffic street sites show a more transport-limited behavior. Wash-off process of the residential catchment appears to be influenced by a composition of different subcatchments.

Significant Reduction of Fecal Bacteria and Suspended Solids Loading by Coastal Best Management Practices

ABSTRACT Mallin, M.A.; Turner, M.I.H.; McIver, M.R.; Toothman, B.R., and Freeman, H.C., 2016. Significant reduction of fecal bacteria and suspended solids loading by coastal best management practices. The Town of Wrightsville Beach, North Carolina, is a resort island that has periodic stormwater runoff problems, affecting local swimming and shellfishing waters from excessive fecal bacteria loading. In 2013–15, the planning, installation, and before-and-after monitoring of several types of best management practices (BMPs) designed to reduce pollutant loading to estuarine waters occurred. A straight pipe carrying runoff directly into estuarine Banks Channel was replaced by a buried infiltration chamber. The infiltration chamber did not reduce fecal bacteria concentrations but caused 93% stormwater discharge reduction, 96% fecal bacteria, 90% Enterococcus load reductions, and a 99% total suspended solids (TSS) load reduction to Banks Channel. Near the town's municipal area a number of curb cuts, reversed sto...

Particulate carbon and nitrogen dynamics in a headwater catchment in Northern Thailand: hysteresis, high yields, and hot spots

AbstractRivers of South and Southeast Asia disgorge large suspended sediment loads, reflecting exceptionally high rates of erosion promoted by natural processes (tectonic and climatic) and anthropogenic (land‐use change) activities that are characteristic of the region. While particulate carbon and nitrogen fluxes have been characterized in some large Asian rivers, less is known about the headwater systems where much sediment and organic material are initially mobilized. This study, conducted in the 74‐km2 Mae Sa Experimental Catchment in northern Thailand, shows that the Sa River is an important source for particulate organic carbon (POC) and particulate organic nitrogen (PON) transported to larger river systems and downstream reservoirs. However, the yields during three years of investigation varied greatly: 5.0–22.3 Mg POC km−2 y−1 and 0.48–2.02 Mg PON km−2 y−1. The 22.3 Mg POC km−2 y−1 yield is the highest reported for any river on the Asian continent. Stream samples collected during 12 storms showed that almost 3% of the total suspended solid load is POC 0.7 µm to 2.0 mm in size. This percentage is higher than other values for most large rivers on the continent. Further, we documented a strong pulse hysteretic behaviour in the stream, whereby peak fluxes of POC and PON are often delayed (anticlockwise hysteresis) or accelerated (clockwise hysteresis) relative to stream flow peaks (or are complex), complicating the prediction of storm‐based or annual particulate carbon and nitrogen fluxes. Stream turbidity and total suspended sediment are reasonable proxies for POC and PON concentrations, while stream discharge is not a good predictor variable. Observed C:N ratios for measured particulate samples range from 3 to 83, with the high‐end values likely associated with fresh (non‐decomposed) vegetative material greater than 2 mm in diameter. The C:N ratio (weighted based on three sediment sizes) for 12 events ranges from 7.5 to 15.3. These modest values reflect the relatively low C:N ratios for small size fractions (0.7–0.63 µm) that comprise 50–90% of the TSS load in the events. Overall, organic material <0.63 µm contribute about 75% of the total POC load and 80% of the PON load. The annual C:N ratio for the river is approximately 10–11. Collectively, our findings indicate the occasionally high yields make the Sa River—and potentially other similar headwater rivers—a hot spot for POC and PON transported to downstream water bodies. Complex hysteresis patterns and high year‐to‐year variability hinders our ability to calculate and predict these yields without continuous, automated monitoring of discharge and turbidity. Copyright © 2016 John Wiley & Sons, Ltd.

Source-Based Modeling Of Urban Stormwater Quality Response to the Selected Scenarios Combining Future Changes in Climate and Socio-Economic Factors.

The assessment of future trends in urban stormwater quality should be most helpful for ensuring the effectiveness of the existing stormwater quality infrastructure in the future and mitigating the associated impacts on receiving waters. Combined effects of expected changes in climate and socio-economic factors on stormwater quality were examined in two urban test catchments by applying a source-based computer model (WinSLAMM) for TSS and three heavy metals (copper, lead, and zinc) for various future scenarios. Generally, both catchments showed similar responses to the future scenarios and pollutant loads were generally more sensitive to changes in socio-economic factors (i.e., increasing traffic intensities, growth and intensification of the individual land-uses) than in the climate. Specifically, for the selected Intermediate socio-economic scenario and two climate change scenarios (RSP=2.6 and 8.5), the TSS loads from both catchments increased by about 10% on average, but when applying the Intermediate climate change scenario (RCP=4.5) for two SSPs, the Sustainability and Security scenarios (SSP1 and SSP3), the TSS loads increased on average by 70%. Furthermore, it was observed that well-designed and maintained stormwater treatment facilities targeting local pollution hotspots exhibited the potential to significantly improve stormwater quality, however, at potentially high costs. In fact, it was possible to reduce pollutant loads from both catchments under the future Sustainability scenario (on average, e.g., TSS were reduced by 20%), compared to the current conditions. The methodology developed in this study was found useful for planning climate change adaptation strategies in the context of local conditions.

Coincident patterns of waste water suspended solids reduction, water transparency increase and chlorophyll decline in Narragansett Bay

Dramatic changes occurred in Narragansett Bay during the 1980s: water clarity increased, while phytoplankton abundance and chlorophyll concentration decreased. We examine how changes in total suspended solids (TSS) loading from wastewater treatment plants may have influenced this decline in phytoplankton chlorophyll. TSS loading, light and phytoplankton observations were compiled and a light- and temperature-dependent Skeletonema-based phytoplankton growth model was applied to evaluate chlorophyll supported by TSS nitrogen during 1983–1995. TSS loading declined 75% from ~0.60×106kgmonth−1 to ~0.15×106kgmonth−1 during 1983–1995. Model results indicate that nitrogen reduction related to TSS reduction was minor and explained a small fraction (~15%) of the long-term chlorophyll decline. The decline in NBay TSS loading appears to have increased water clarity and in situ irradiance and contributed to the long-term chlorophyll decline by inducing a physiological response of a ~20% reduction in chlorophyll per cell.

Seasonal Variability in Stormwater Quality Treatment of Permeable Pavements Situated Over Heavy Clay and in a Cold Climate

Permeable pavements mitigate the impacts of urbanization on surface waters through pollutant load reduction, both by sequestration of pollutants and stormwater volume reduction through exfiltration. This study examined the non-winter water quality performance of two side-by-side permeable pavements in the Ohio snowbelt. The permeable interlocking concrete pavements were designed to drain impervious catchments 2.2 (large) and 7.2 (small) times larger than their surface area, were located over clay soils, and incorporated the internal water storage design feature. Nutrient reduction was similar to past studies—organic nitrogen and particulate phosphorus were removed through filtration and settling, while dissolved constituents received little treatment. Because of 16 and 32 % volume reductions in the small and large installations, respectively, nutrient loads were often significantly reduced but generally by less than 50 %. Aluminum, calcium, iron, magnesium, lead, chloride, and total suspended solids (TSS) concentrations and loads often increased after passing through the permeable pavements; effluent TSS loads were three- to five-fold higher than influent TSS loads. This was apparently due to seasonal release of clay- and silt-sized particles from the soils underlying the permeable pavement and inversely related to elapsed time since winter. The application of de-icing salt is thought to have caused deflocculation of the underlying soils, allowing particulates to exit with stormwater as it discharged from the underdrain of the permeable pavements. By autumn, both permeable pavements discharged metals and TSS concentrations similar to others in the literature, suggesting the de-icing effects lasted 3–6 months post-winter. Sodium may substantially affect the performance of permeable pavements following winter de-icing salt application, particularly when 2:1 clay minerals, such as vermiculites and smectites, predominate.

Production and Investigation of Biochemical and Organoleptic Changes of Mixed Fruit Juice during Storage Period

A blend of different fruits has a great specialty on its splendid color, flavor, taste and nutritional contents. The purpose of this study was to explore the acceptable formulation of mixed fruit juice with better storage stability. The mixed fruit juice samples were prepared in four formulations incorporating pineapple, papaya, banana and orange with the addition of sugar (10%) and sodium benzoate (0.08%). Then the juices were heated for 5 minutes at 65oC, bottled in air tight plastic bottle and stored at 4oC for 180 days and 25oC for 120 days. It was found that TSS, acidity, total sugar, and bacterial load increased slightly, but vitamin C and pH decreased gradually during the storage periods. Fading of color and off flavor was found at the end of storage period. The storage temperature of 4oC was more effective to hold the quality of juice samples against biochemical changes. T 4 sample showed better retention of vitamin C, pH, acidity and total sugar than other samples both at 4oC and 25oC. Panelists preferred the T4 sample most, which showed maximum hedonic scale ‘8’ point on sensory properties. It is also observed that T 4 ensured the better shelf life to preserve the color, flavor and taste until 150 days at 4oC and 105 days at 25oC.

A multi-stakeholder framework for urban runoff quality management: Application of social choice and bargaining techniques

In this paper, an integrated framework is proposed for urban runoff management. To control and improve runoff quality and quantity, Low Impact Development (LID) practices are utilized. In order to determine the LIDs' areas and locations, the Non-dominated Sorting Genetic Algorithm-II (NSGA-II), which considers three objective functions of minimizing runoff volume, runoff pollution and implementation cost of LIDs, is utilized. In this framework, the Storm Water Management Model (SWMM) is used for stream flow simulation. The non-dominated solutions provided by the NSGA-II are considered as management scenarios. To select the most preferred scenario, interactions among the main stakeholders in the study area with conflicting utilities are incorporated by utilizing bargaining models including a non-cooperative game, Nash model and social choice procedures of Borda count and approval voting. Moreover, a new social choice procedure, named pairwise voting method, is proposed and applied. Based on each conflict resolution approach, a scenario is identified as the ideal solution providing the LIDs' areas, locations and implementation cost. The proposed framework is applied for urban water quality and quantity management in the northern part of Tehran metropolitan city, Iran. Results show that the proposed pairwise voting method tends to select a scenario with a higher percentage of reduction in TSS (Total Suspended Solid) load and runoff volume, in comparison with the Borda count and approval voting methods. Besides, the Nash method presents a management scenario with the highest cost for LIDs' implementation and the maximum values for percentage of runoff volume reduction and TSS removal. The results also signify that selection of an appropriate management scenario by stakeholders in the study area depends on the available financial resources and the relative importance of runoff quality improvement in comparison with reducing the runoff volume.

Water quality in the St. Louis River Area of Concern, Lake Superior: Historical and current conditions and delisting implications

Abstract Water quality in the St. Louis River Area of Concern (AOC) was assessed at two stations over a 60 year period (1953–2013) and system-wide for 2012–2013 to determine if the AOC beneficial use impairment (BUI) of “Excessive loading of sediment and nutrients” should be considered for removal. Based on the time-series analysis, concentration and loading of total suspended solids and total phosphorus to Lake Superior from the St. Louis River have decreased over time, and episodic hypoxia in the mainstem of the estuary was eliminated after 1975. Detection of temporal patterns in nitrogen concentration and loading, particularly in the lower estuary, were complicated by Lake Superior nitrogen inputs and changes in wastewater treatment practices. For the system-wide assessment, sample locations were based on a probabilistic survey design. In 2012 and 2013, there was significant monthly (May–October) variability in water quality constituents. Based on area-weighted estimates, 60–85% of the estuary surface area was below BUI criterion for total phosphorus, total suspended solids, and chlorophyll a . Water quality in the western arm of Lake Superior in 2013 was indicative of oligotrophic conditions, satisfying delisting requirements. The long-term improvements in water quality followed improvements in watershed land-use practices and treatment of wastewater. The stratified system-wide survey provided unbiased estimates of spatial and temporal condition and identified some outlier sites. The data from this study supports the BUI removal process for the St. Louis River AOC.

Evaluation of stormwater runoff quality during monsoon and inter-monsoon seasons at tropical urban catchments

ABSTRACTInformation on pollution level and the influence of a hydrologic regime on stormwater pollutant loading in tropical urban areas remains scarce. More local data is still required, as rainfall and runoff generation processes in tropical environment differ greatly from temperate regions. This study compares the stormwater runoff quality from urban catchments during monsoon and inter-monsoon seasons in the south of Peninsular Malaysia. Stormwater samples and flow rate data were collected from 38 storm events at three individual sites. Samples were analysed for total suspended solids (TSS), 5-day biochemical oxygen demand (BOD), chemical oxygen demand (COD), oil and grease (O&G), nitrate nitrogen (NO3-N), ammoniacal nitrogen (NH3-N), and total phosphorus (TP). Event mean concentration (EMC) was calculated for each pollutant for every monitored storm event at all study sites. The Mann–Whitney test was used to test for significance (p < 5%) in differences between the median EMCs of the pollutants. The results revealed that EMCs for stormwater runoff during the monsoon season were lower than that during the inter-monsoon season. Significant differences (p < .05) were found for EMC values for TSS, oil and grease, NH3-N, and TP but not for BOD, COD, and NO3-N. Stormwater pollutant loading of TSS, NH3-N, and TP is higher during the inter-monsoon season while BOD, COD, and NO3-N show higher loadings during the monsoon season. A better understanding of pollutant transport mechanisms will aid in formulating an effective stormwater management measures to control the urban stormwater pollution in the tropics.