Application of recycled sludge to stabilize coagulation process

2016 ◽  
Vol 16 (6) ◽  
pp. 1571-1579
Author(s):  
Jolanta Gumińska ◽  
Adam Gumiński
Keyword(s):  
Water Quality ◽  
Conventional Treatment ◽  
Fine Particles ◽  
Coagulation Process ◽  
Optimal Value ◽  
Filter Bed ◽  
Polyaluminium Chloride ◽  
Variable Quality

In conventional treatment of variable quality mountain water, an inability to immediately adjust the coagulant dose to variations in water quality causes overdose or underdose of coagulant in relation to its optimal value. The results of the research showed that the reuse of post-coagulation sludge was an effective method to maintain high and stable coagulation effectiveness under both polyaluminium chloride (PACl) overdose and underdose conditions. Recycled sludge contains a large portion of insoluble aluminium hydroxides that could be utilized in underdose PACl conditions. Post-coagulation sludge recycled to a flocculation tank enabled the reduction of a dose of low basicity PACl by 15% compared to a dose required in conventional coagulation. In periods of coagulant overdosing, sludge addition prevented an increase in the number of fine particles in an outflow from sedimentation tanks that could not be retained in a filter bed.

Particle counter as a tool to control pre-hydrolyzed coagulant dosing and rapid filtration efficiency in a conventional treatment system

2014 ◽  
Vol 71 (4) ◽  
pp. 615-621 ◽  
Author(s):  
Jolanta Gumińska ◽  
Marcin Kłos
Keyword(s):  
Water Quality ◽  
Water Treatment ◽  
Fine Particles ◽  
High Surface ◽  
Treatment Plant ◽  
Water Treatment Plant ◽  
Filtration Efficiency ◽  
Treatment System ◽  
Aluminum Speciation ◽  
Filter Bed

Filtration efficiency in a conventional water treatment system was analyzed in the context of pre-hydrolyzed coagulant overdosing. Two commercial coagulants of different aluminum speciation were tested. A study was carried out at a water treatment plant supplied with raw water of variable quality. The lack of stability of water quality caused many problems with maintaining the optimal coagulant dose. The achieved results show that the type of coagulant had a very strong influence on the effectiveness of filtration resulting from the application of an improper coagulant dose. The overdosing of high basicity coagulant (PAC85) caused a significant increase of fine particles in the outflow from the sedimentation tanks, which could not be retained in the filter bed due to high surface charge and the small size of hydrolysis products. When using a coagulant of lower basicity (PAC70), it was much easier to control the dose of coagulant and to adjust it to the changing water quality.

What Advantages Can Be Expected from the Acceptance of Variable Quality Standards for Sewage Treatment Effluents?

1988 ◽  
Vol 20 (4-5) ◽  
pp. 249-251
Author(s):  
Jacques Bernard
Keyword(s):  
Water Quality ◽  
Sewage Treatment ◽  
Quality Standards ◽  
Quality Level ◽  
Environment Protection ◽  
Economical Benefit ◽  
Quality Objective ◽  
Set Up ◽  
Variable Quality

The flow and the water quality of the rivers vary throughout the year. Very frequently the environment protection authorities set up a quality objective for the river water and this mini mum quality level is constant. So, it wou1d seem possible to accept variable quality standards for plant effluents. A first approach of the problem,by a small French task group,based on three actual cases leads to the provisory conclusion that such a regulation is suitable and presents economical benefit only in some very limit ed cases.

Control of coagulation process by dual wavelength article analyzer

1997 ◽  
Vol 36 (4) ◽  
pp. 135-142 ◽  
Author(s):  
Norihito Tambo ◽  
Yoshihiko Matsui ◽  
Ken-ichi Kurotani ◽  
Masakazu Kubota ◽  
Hirohide Akiyama ◽  
...  
Keyword(s):  
Water Quality ◽  
Control System ◽  
Predictive Control ◽  
Control Method ◽  
Feedforward Control ◽  
Raw Water ◽  
Floc Size ◽  
Coagulation Process ◽  
Series Of Experiments ◽  
Size Data

A coagulation process for water purification plants mainly uses feedforward control based on raw water quality and empirical data and requires operator's help. We developed a new floc sensor for measuring floc size in a flush mixer to be used for floc control. A control system using model predictive control was developed on the floc size data. A series of experiments was performed to confirm controllability of settled water quality by controlling flush mixer floc size. An automatic control with feedback from the coagulation process was evaluated as practical and reliable. Finally this new control method was applied for actual plant and evaluated as practical.

scholarly journals Removing Iron and Organic Substances from Water over the Course of Its Treatment with the Application of Average and Highly Alkaline Polyaluminium Chlorides

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1367
Author(s):  
Izabela Krupińska
Keyword(s):  
Water Treatment ◽  
Human Consumption ◽  
Iron Ions ◽  
Organic Substances ◽  
Iron Compounds ◽  
Polyaluminum Chloride ◽  
Coagulation Process ◽  
Lack Of Information ◽  
Organic Complexes ◽  
Polyaluminium Chloride

In topic-related literature pertaining to the treatment of water, there is a lack of information on the influence of iron ions in highly basic polyaluminum chlorides on the efficiency of purifying water with increased contents of organic substance. The aim of this work was to determine the changes in the content of organic substances as well as iron compounds in water intended for human consumption following unit treatment processes with particular attention paid to the coagulation process. As coagulants, polyaluminium chloride PAXXL10 with an alkalinity of 70%, as well as polyaluminium chloride PAXXL1911 with an alkalinity of 85% the composition of which also contained iron, were tested. The analysis of the obtained results showed that iron compounds and organic substances were removed to the greatest extent by the coagulation process, which also had a significant influence on the final efficiency of water treatment. The effectiveness of water treatment was determined by the type of tested polyaluminum chloride, which influenced the formation of iron-organic complexes. The reason behind the formation of colored iron-organic complexes during coagulation using PAXXL1911 coagulant was the high pH (approx. 8), at which the functional groups of organic substances, due to their dissociation, are more reactive in relation to iron, and possibly the fact of introducing additional iron ions along with the coagulant.

scholarly journals THE IMPACT OF THE OXIDISING AGENT TYPE AND COAGULANT TYPE ON THE EFFECTIVENESS OF COAGULATION IN THE REMOVAL OF POLLUTANTS FROM UNDERGROUND WATER WITH AN INCREASED CONTENT OF ORGANIC SUBSTANCES

2016 ◽  
Vol 24 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Izabela KRUPIŃSKA
Keyword(s):  
Hydrogen Peroxide ◽  
Underground Water ◽  
Total Iron ◽  
Pollutant Removal ◽  
Organic Substances ◽  
Aluminium Sulphate ◽  
Coagulation Process ◽  
Groundwater Samples ◽  
The Impact ◽  
Polyaluminium Chloride

The article presents the results of studies concerning the impact of the method of Fe(II) ion oxidisation on the effectiveness of coagulation in the removal of pollutants from underground water with an increased content of organic substances (TOC up to 5.338mgC/dm3). In order to oxidise the Fe (II) ions before the coagulation process, the underground water was subjected to aeration, or either potassium manganate (VII) or hydrogen peroxide were dosed in the stoichiometric amount in view of the concentration of Fe (II). The efficiencies of three coagulants were compared: that of aluminium sulphate (VI), polyaluminium chloride (PAX XL-60) and iron (III) sulphate (VI) – PIX-112. Coagulant doses expressed in mgal/dm3 or mgfe/dm3 and changed within the range of 1 to 6 mgal(Fe)/dm3. Volume coagulation was performed in 1-dm3 groundwater samples using 1-minute rapid mix (250 rpm) and 25-minute slow mix (30 rpm) followed by 2-hour sedimentation. It has been proven that the type of oxidising agent and coagulant, as well as their dose, co-determines the effectiveness of the removal of the pollutants. Among the used methods of iron (II) oxidisation, the best effects have been achieved by potassium manganate (VII) with regards to the effects of the reduction of colour, turbidity, concentration of manganese and organic substances, and with regards to the extent of total iron removal, oxidisation with dissolved oxygen was the most effective solution. Hydrogen peroxide was the least useful oxidising agent. Regardless of the oxidising agent the best results in the removal of pollutants in the coagulation process were produced by the coagulant: pre-hydrolysed polyaluminium chloride PAX XL-60, and the worst by the iron coagulant: iron (III) sulphate (VI). Analysis of the results of the studies also showed that the effectiveness of pollutant removal from the underground water in the coagulation process was decreased together with an increase in the value of the TOC/Fetot only in the case of water samples which, after aeration, differed in terms of the coefficient of organic substances and total iron (D). Such a relationship was not found when potassium manganate (VII) and hydrogen peroxide were used for oxidisation before the coagulation process.

Flue gas fine treatment by ejecting technology

2018 ◽  
Vol 233 (12) ◽  
pp. 4311-4318
Author(s):  
Junyou Zhao ◽  
Chongning Liu ◽  
Yafei Dong ◽  
Qingqiang He ◽  
Fawei Wan ◽  
...  
Keyword(s):  
Sulfur Dioxide ◽  
Flue Gas ◽  
Fine Particles ◽  
Dust Particles ◽  
Gas Emissions ◽  
Gas Processing ◽  
Optimal Value ◽  
Simulation Results ◽  
Main Components ◽  
Processing Device

PM2.5 refers to fine particles with a diameter of 2.5 µm or less in the air. With PM2.5 continuously impacting people's lives, researchers are starting to pay more attention on the treatment of flue gas emitted from coal-fired boilers. This paper introduces a treatment device for ejected fine flue gas. The device uses ejectors to effectively remove acid substances and large dust particles contained in flue gas, and uses air dynamic ultrasonic atomizer to eliminate micro dust particles effectively. The overall scheme of the flue gas processing device is designed, the principle and simulation results of the main components of the ejector are studied, and the optimal value of the ejector ratio is determined by experiments. Finally, the efficiency of processing dust and sulfur dioxide in the flue gas is tested during experiments on the industrial worksite. For the gas emissions from domestic small- and medium-sized coal-fired boilers, this device is more efficient and costs less energy.

Upgrading conventional treatment processes for water quality improvement - a pilot study

2002 ◽  
Vol 2 (5-6) ◽  
pp. 165-171
Author(s):  
J.-J. Chen ◽  
H.-H. Yeh ◽  
I.-C. Tseng ◽  
T.-F. Lin ◽  
W.-L. Lai
Keyword(s):  
Water Quality ◽  
Conventional Treatment ◽  
Profile Analysis ◽  
Eutrophic Lake ◽  
Total Hardness ◽  
The Third ◽  
Treatment Processes ◽  
Taste And Odor ◽  
Pilot Plant Test ◽  
Plant Test

Cheng Ching Lake Water Works (CCLWW), located in southern Taiwan, draws its raw water from a eutrophic lake, which is treated by conventional processes, including pre-chlorination, coagulation, sedimentation, filtration, and disinfection. As the taste- and odor-causing compounds from algae cannot be completely removed by conventional treatment processes, and the hardness is high, there are complaints about water quality. In searching for suitable processes to upgrade the existing facilities, a two-year pilot plant test was conducted. In total 13 processes were tested, which could be divided into three groups. The main feature of the first group was the modification of the existing conventional treatment processes, which included eliminating pre-chlorination and incorporating GAC. The second group incorporated pre- and post-ozonation, GAC bed, with or without pellet softening, into the conventional processes. The third group featured membrane processes, mainly nanofiltration (NF) and its various pretreatment processes, such as microfiltration (MF) or ultrafiltration (UF). The results show that although the first group has higher removal rates of dissolved organic and disinfection by-product precursors, as measured by NPDOC and THMFP, respectively, than those from the existing full-scale plants, the improvement in taste and odour was not adequate. For the second group, the dissolved organic parameters and biostability of the finished water were further improved, and half of the total hardness could be removed by pellet softening. However, earthy and fishy odours still could be detected occasionally by flavour profile analysis. Generally speaking, the third group with processes involving NF could produce the highest quality finished water: no matter organic, inorganic, organoleptic parameters, or biostability were concerned.

Potential of sediment reuse for soil fertilization and water conservation in drylands

2020 ◽  
Author(s):  
Pedro Medeiros ◽  
Brennda Braga ◽  
Camila Lira ◽  
Arlena Brosinsky ◽  
Saskia Foerster ◽  
...  
Keyword(s):  
Water Quality ◽  
Water Conservation ◽  
Crop Production ◽  
Fine Particles ◽  
Small Scale ◽  
Soil Fertilization ◽  
Study Region ◽  
Water Quality Simulation ◽  
Nutritional Deficit ◽  
Maize Cultivation

<p>In dry environments, society has long implemented infrastructure to adapt to water scarcity, but unanticipated feedbacks have threatened the supply-demand balance. For instance, construction of dams increases the water residence time in highly impounded basins, causing sediment and nutrient accumulation in water supply reservoirs. Reuse of reservoirs’ sediment as fertilizer sustainably benefits agricultural and water systems by: replacing fine particles and nutrients to soils, previously lost by erosion; recovering water quantity and quality by the removal of nutrient-enriched sediments from reservoirs. In the last 5 years we have assessed the potential of the sediment reuse technique for soil fertilization and water conservation in the semiarid Ceará State (149 000 km²), Brazil, where there is a dense network of more than 20 000 dams with considerable silting and eutrophication. Our previous studies demonstrated that:</p><ul><li>Local features contribute to the adoption of the proposed technique: (i) small reservoirs fall dry frequently, exposing the sediments for excavation without the need for dredging; (ii) in general, soils present nutritional deficit and, under natural conditions, crop production is limited to patches of fertile soils; (iii) small scale agriculture plays a major role for livelihood of the rural population;</li> <li>Recycling of nutrients from sediments is technically feasible: an experiment with a mixture of soil and sediment as substrate produced statistically higher growth and enzymes’ activity of sunflower plants, compared to the cultivation directly in the soil or with addition of synthetic fertilizers;</li> <li>Sediment reuse is economically feasible: soil fertilization through sediments for maize cultivation may reduce costs by up to 29 % compared to traditional fertilization;</li> <li>Removal of sediment from reservoirs may improve the water quality: simulation of annual removal of sediments when a reservoir of the study region is completely empty indicates a change on the trophic level, from eutrophic or higher to mesotrophic or lower, in 10 % of the time.</li> </ul><p>In spite of the recent advances, sediment recycling must go through some phases in order to be included in the public policy agenda. Our ongoing and planned studies focus on the generation of basic data, real-scale testing, simulations under diverse environmental contexts, elaboration of guidelines and disclosure. Spectroscopy has been successfully applied to characterize sediment and soil properties and reduce the costly laboratory analysis. Additionally, data acquisition will be supported by remote sensing approaches based on hyperspectral satellite images that will become available in the near future (Prisma, EnMAP). Such data will be used to estimate nutrient availability in sediments and deficit in the soils to generate a map of the sediment reuse potential in Ceará. Field scale growth experiments are to be conducted for the main crops cultivated in the study region, in contrast to the indoor controlled conditions of our previous assessment. Furthermore, we are developing a modelling tool to quantify the impacts of the sediment reuse practice on water quality, enabling us to expand our previous study to other reservoirs and to test its effectiveness to water conservation.</p>

scholarly journals Effective Monitoring of Small River Basins

2002 ◽  
Vol 2 ◽  
pp. 1017-1021
Author(s):  
W. Symader ◽  
R. Bierl ◽  
A. Krein
Keyword(s):  
Water Quality ◽  
Fine Particles ◽  
River Basins ◽  
Small River ◽  
Chemical Data ◽  
Quality Data ◽  
Monitoring Station ◽  
Small Rivers ◽  
Water Quality Data ◽  
Short Pulses

As the transport of many pollutants occurs during high floods monitoring programs must focus on these intermittent events. In small rivers the pollutants start their travel as short pulses often associated with fine particles, but disperse on their way downstreams. Therefore the chemical data of a flood event are only representative of a small part of the basin adjacent to the monitoring station. This is usually not taken into account by evaluating water quality data.

Fractal Dimension of Floc Growth in Micro-Coagulation Stage I: Using to Forecast Water Quality of Settled Water

2011 ◽  
Vol 243-249 ◽  
pp. 4831-4834 ◽  
Author(s):  
Jun Nan ◽  
Hao Yu Li ◽  
Wei Peng He
Keyword(s):  
Water Quality ◽  
Particle Size ◽  
Fractal Dimension ◽  
Particle Number ◽  
Coagulation Process ◽  
Total Particle Number ◽  
Total Particle ◽  
On Line ◽  
Line Detector

The coagulation experiments, with Kaolin as objects, aluminum chloride (PAC) as coagulant, were accomplished under different conditions. In the experiment, the particle size distribution and turbidity in water were detected by on-line detector. Result showed that all floc changed in speed in the first 5 min of the coagulation process and the fractal dimension of floc growth in the first 4 min of coagulation process had best linear relation (R2 was biggest and more than 0.92 )with turbidity, total particle number and the number of particle size <5µm of settled water. The fractal dimension had a direct ratio relation with water quality of settled water and could be used as a factor to forecast water quality of settled water.

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