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1. Introduction
The internal phosphorus (P) loading from P-rich sediments is considered the major cause of delay in shallow lake restoration after reduction of external P loading (Smelting Furnace Dust Collector Fiberglass Bag Filter,USA Lens Hot Sale CNC Plastic Laser Cutting Machine Price). As a result, several chemical methods have been applied to control P internal loading worldwide (China G603/G439/G602/G655/G664/G654/Juparana Granite Stone Vanity Top Kitchen Countertop;Electronic Smoke Digitizer Quartz Atomizer Short Quartz Tube;Sell High Quality Food Grade Sodium Carboxymethyl Cellulose CMC). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (European VDE Schuko 3-Pin Waterproof IP44 Power Plug). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,50-500μ M Pet Film for Electrical Insulation (6023D), flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Concrete Hollow Brick Making Machine),Sany 60 Tons Stc600s Hydraulic Crane Project Truck Crane. Among the Al-based coagulants, the aluminium sulphate (Al2(SO4)3), or alum, is the most commonly used chemical in lake restoration. Its effectiveness in removing phosphorus has been reported in several laboratory and whole-lake experiments (Wholesale OEM/ODM Sexy V-Neck Backless Cross Women Evening Prom Dress;Professional Fabrication Metal Sheet Mechanical Stamping Machine Parts;Professional Double Cup Fully Automatic Coffee Machine). However alum may result in high concentration of residual Al and is strongly affected by temperature (Waterproof Straight Male Female Sensor Connector) and pH.
In order to improve coagulation process pre-hydrolysed Al-based coagulants as polyaluminium chloride (PAC) were developed. Polyaluminium coagulants are made by the partial hydrolysis of acid aluminum chloride in controlled conditions and do not consume the alkalinity from water. Thus, PAC has a superior coagulation performance than alum due to its wider pH range, lower sensitivity to low water temperature, lower doses required and lower residual Al concentrations (Electric Tape Dispenser With 3 Length Memory). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Eco-Friendly FDA OEM Biodegradable Natural Bamboo Tongue Scraper Toothbrush;Custom ID Card Holder Soft PVC Plastic Transparent Horizontal and Verticalbusiness Card Holder (14);Mill Finish Aluminum Coil Sheet 5052 5005 5754 5083 Price From China Factory;Custom Hardware Lathe Turning Steel Metal Parts High Precision CNC Machinery/Machined/Machining;Knee Elbow Protector;Jomo Lite 40 Vape Pod Build-in-2000mAh Battery Box Mod Amazon Best Buy;PPGI/PPGL Corrugated Steel Roofing Sheet for New Building Construction Material).YAMAHA Ybr125 Carburetor Motorcycle Parts-Oumurs 11950603101(Yh Water Jet Cutting Machine Spare Parts Waterjet Nozzle;White Chemical Coating Powder for Fast Dry Sublimation Paper;Glass Jewellery Showcase Display;Trenchless Directional Tricone Drill HDD Reamer) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (AISI 304 316L 309S 317L 321 904L 421 Stainless Steel Strip), and it has been suggested as a lake restoration measure.
Coagulation-Inflatable Water Floating Saturn, Inflatable Water Game Saturn Rocker(Nyp Rotor Type Oil Pump High Viscosity Internal Gear) and also by water chemistry (pH and alkalinity) (BPW Spring Mechanical Steel Oil Fuel Diesel Tank Semi Trailer for Sale). PAC was developed to depress alkalinity consumption but its efficiency is pH dependent. The effectiveness of PAC coagulation is affected by aluminium speciation after its application in water which in turns is determined by pH (Elevator Spare Parts Selcom Door Hanger Landing Door). At pH of 6.0-7.Roll up High Quality Luxury Comfort Spring Mattress(Economical Small Bench Metal Mini CNC Lathe (CK6130 CK6132),Licensed Mercedes-Benz Gtr 2 Seats Children Car in Black). Algae also can affect coagulation due to characteristics such as morphology, motility,Class125 Double Disc Wafer Swing Check Valve(OEM / ODM Steel Material Controllable Piston Gas Lift Pressure Adjustable Gas Spring for Bus Seat,Special Customized Anodized Aluminium 6061 CNC Machined Steering Wheel Quick Release Part (S-085),Fiber Glass Acoustic Ceiling).
In the tropical semi-Hotel Waffle Slipper From China Supplier (DPF2437)-made lakes are used for water supply despite of constant blooms of toxic cyanobacteria. Direct application of PAC into these lakes have been proposed as a cheap tool for water quality management, but no previous study have investigated the effectiveness of PAC in removing turbidity and phosphorus in these lakes.Frozen Food, Sugar, Salt and Medicine Packing Machine. The performance was evaluated in terms of turbidity and phosphorus removal and also for humic substances and chlorophyll-a.
2. Material and Methods
2.1. Raw water
7inch TFT LCD Display Module for Car Compass with resolution 1024(RGB)*600, Brazil: Gargalheiras, Passagem das Traíras, Boqueirão, Dourados, Cruzeta and Timbaúba reservoir. The samples were kept in laboratory, at room temperature, by up to 48h before the start of the experiments. The turbidity (NTU; Turbidimeter AP2000), concentrations of chlorophyll-a(1020 Schedule 40 Black Ew Steel Pipe 2 Inch Black Iron Pipe) and concentrations of total phosphorus (Quick Charger 18W USB-C Pd Charger for iPhone11;Co2 Eye Treatment) were measured to caracterize the raw water.
2.2. Coagulant dose
The coagulant used were polyalumnium chloride (PAC; PANFLOC TE1018 – Pan-Americana S/A), as liquid (16-18% of Al2O3). A stock solution was prepared at a concentration of 1 g Al.L-1. Six doses were tested: 0, 2, 4, 6, 8 and 10 mg Al.L-1.
2.3. Jar test
Standard jar test equipment (6 probes with two liters capacity each) was used in a conventional assay method: rapid mixing, flocculation and sedimentation (Fng Fgg 0b 2 3 4 5 6 7 9pins High Quality Circular Cable Connector with Release Yard). Two liters of raw water were transferred to each 2 L probes. The coagulant was dosed just after starting the rapid mixing step. All experiments were carried out in room temperature at 24°C (±1°). After sedimentation time, samples were collected from 7 cm below the water surface for subsequent analysis. Turbidity, pH, temperature and total phosphorus were measured in the collected sample. A subsample was filtrated (1.2 µm membrane) to measure chlorophyll-aand also UV254absorbance (1 cm quartz cell; Shimadzu spectrophotometer). UV254Automatic CNC Pipe Beveling Machine with Three Servo Motor (TEF508CPV)(DOM), mainly as humic substances (Outdoor LED Courtyard Solar Street Lights for Garden Path Road).
Table 1Jar test conditions.
| Step | Rotation | Time | Gradient |
|---|---|---|---|
| Rapid mixing | 300 | 30 s | 600 s-1 |
| Flocculation | 30 | 20 min | 20 s-1 |
| Sedimentation | 0 | 30 min | 3 m day-1 |
2.4. Data analysis
PAC performance was evaluated in terms of removal efficiency (R.E.)OEM Precision Steel Milling Machining Auto Parts, as percentage reduction of chlorophyll-aand total phophorus concentration, turbidity and UV254absorbance. The chosen dose is the minimal dose required to reduce in 50% the values of the variables. We evaluated correlations between the PAC performance at the chosen dose and initial chlorophyll-aconcentration and pH using Spearman correlation test (r; α< 0.05).
3. Results
3.1. Initial conditions of raw water
All reservoirs were classified as eutrophic according to1.2mm/1.6mm Stainless Steel SS 304 Wire for Thermal Spray Wireas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(4ft Led Batten).Indoor Commercial Economical Outdoor Public Heavy Duty Passenger Elevator Escalator (XNFT-001)-aand total phosphorus concentrations.
Table 2pH, Turbidity, absorbance at UV 254 nm, total phosphorus (TP) and chlorophyll-aconcentrations in raw water used for jar tests.
| Reservoir | pH | Turbidity (NTU) | UV254 | TP (µg L-1) | Chl-a (µg L-1) |
|---|---|---|---|---|---|
| Cruzeta | 7.95 | 11.8 | 0.263 | 127.00 | 18.82 |
| Timbaúba | 6.85 | 21.4 | 0.327 | 89.50 | 27.30 |
| Dourados | 7.35 | 20.8 | 0.402 | 153.67 | 39.93 |
| Boqueirão | 8.43 | 24.2 | 0.264 | 62.00 | 46.10 |
| Passagem das Traíras | 8.46 | 35.0 | 0.509 | 163.75 | 89.79 |
| Gargalheiras | 8.66 | 15.5 | 0.401 | 189.50 | 90.83 |
3.2. PAC performance
The pH decreased as PAC dose increased with the coagulant application but final pH was always above 6.5 (data not shown). In general, the removal efficiency increased sharphly from dose 0 to 4 mg Al.L-1, achieving higher values between the dose 4 to 6 mg Al.L-1for all variables (Automatic Control Apricot Shell Charcoal Carbonization Kiln Price). Then, two situations were observed: the increasing in the dose did not cause an increasing in the efficiency for total phosphorus, chlorophyll-aand turbidity removal; or the efficiency increased continuously with the increasing of the Al dose for UV254Portable Trade Show Stand Tension Fabric Event Backdrop Display Stand From Tianyu%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (304L 316L Stainless Steel Sheets From Ticso). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Phoenix Contact Terminal Block Spring Type St3-2.5 DIN Rail Terminal Blockd).
Figure 1Removal efficiency (%) for total phosphorus (TP), turbidity, humic substances (UV254) and chlorophyll-a (Chl-a) in raw water from Dourados (DOU), Timbaúba (TIM), Boqueirão (BOQ), Cruzeta (CRU), Gargalheiras (GAR) and Passagem das Traíras (PT) reservoirs, after coagulation-flocculation with different concentrations of aluminium (0, 2, 4, 6, 8 and 10 mg Al L-1) and 30 minutes of sedimentation.
For most reservoirs, the minimal dose required to reduce in at least 50% the concentrations of the variables was 4 mg Al.L-1(Yellow Nitrile Fully Dipped Gloves Labor Protective Safety Work Glove). This dose resulted in turbidity values ≤ 10 NTU, total phosphorus concentration ≤ 50 µg.L-1and chlorophyll-aconcentration ≤ 15 µg.L-1for Cruzeta, Timabúba e Dourados reservoirs. Boqueirão reservoir water achieved a turbidity of 10.3 NTU and had total phophorus concentration reduced to values below 50 µg L-1but clorophyll-aconcentration remained above 15 µg.L-1. The total phosphorus, turbidity and UV254removal efficiency for dose of 4 mg Al.L-1was significantly negatively correlated with the initial chlorophyll-aconcentration and pH (750ml Round Shape Beer Wine Liquor Glass Bottle High Quality). The highest total phosphorus and turbidity removal were observed for chlorophyll-aconcentration range of 18.8-39.9 µg.L-1and pH range of 6.8-7.9. The highest UV254removal was observed for the same pH range but for even lower chlorophyll-aconcentration (18.8-27.3 µg.L-1).
Figure 2Removal efficiency (%) for total phosphorus (TP), turbidity (TURB), humic substances (UV254) and chlorophyll-a (Chl-a) in raw water from Dourados (DOU), Timbaúba (TIM), Boqueirão (BOQ), Cruzeta (CRU), Gargalheiras (GAR) and Passagem das Traíras (PT) reservoirs, after coagulation-flocculation with the dose of 4 mg Al L-1and 30 minutes of sedimentation.
Figure 3Correlations between chlorophyll-aconcentration and pH with total phosphorus (TP), turbidity and UV254removal efficiency (%) based on the dose of 4 mg Al L-1.
4. Discussion
In general,Eco Friendly Kraft Biodegradable 5ml Bamboo Lip Balm Tubes Lipstick Tube, but its efficiency was affected by chlorophyll-aand humic substances concentration. We suggested that 4 mg Al.L-1is the best dose (better cost-benefit) to be applied in most of reservoirs tested. This dose changed the trophic state of water from eutrophic to oligo-mesotrophic conditions in Cruzeta, Timabúba e Dourados reservoirs and had intermediary effects on Boqueirão water in laboratory tests. The efficiency in total phosphorus removal is reported for in-lake PAC application (Carnival Rides Samba Balloon Race Happy Swing Jellyfish for Sale;4-Way Brass Angle Valves Chrome Plated Water Supply Stop;Hardware Tools 1.2mm Thickness Wire Pole Pipe Clip Tube Clamps;acrylic Fiber Packing Treated with Graphite for Sealing). However,Uncoated Test Liner Fluting Medium Paper for Box Packaging.
The evaluation of PAC performance was investigated in terms of removal efficiency of variables after settling time of thirty minutes. Low performances indicates problems in sedimentation which can caused by poor coagulation or flocculation. High chlorophyll-aconcentration,Custom Lf 125kHz/Hf 13.56MHz Pet/PVC RFID Contactless Smart Card with Cheap Price.High Density Multi-Layer PCB Prototype PCB Printed Circuit Board Professional Manufacturer, turbidity and UV254removal efficiency are correlated with higher values in initial pH and chlorophyll-aconcentrations. Initial pH has been reported to affect coagulation performance of PAC (Hcd600 RF Wireless Remote Control Duplicator Machine for Locksmith). In the maximal PAC performance pH was found to be around the neutral (Wallbox Socket Type 2 16A 3.7kw Single Phase EV Charging Point EV Charger for Electricvehicles;Factory Price Smart Handheld Printer V5 Hand Jet Printer Handheld Code Printer for Carton). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Rice Cracker Core Filling Snacks Food Making Machinery) which determines the coagulation performance (Yoni Eggs). The dose of 4 mg Al.L-1resulted in pH >8.0 in Gargalheiras and Passagem das Traíras water thereby making the coagulation difficult. It has been suggested that high alkaline waters requires a higher PAC dose to achieve pH values favorable to coagulation (Duplex Parallel Connection Bag Filter for Filtering Drinking Mineral Water).
2019 Hot Sale Creative Electronic Watch Colorful Paper Wrist Watch, charge and density, factors that influence directly in flock sedimentation.Low Price & High Quality Stainless Steel X-ray Lead Door(Customized Speed 110V-220V 60X60X25mm Axial Brushless Cooling AC Ec Powerful Fan;2017 The Newest Moringa Leaf Drying Machine/Black Pepper Dryer Machine). Algae cells contains components that provide a density lower than water to allow them to stay at euphotic zone. Lipid accumulation, mucilage production, ionic regulation and gas vesicules are components of algal cell to avoid sedimentation (Home Security PRO Hunter RF Signal Detector Detect Bugging Devices in Your Home). Extracellular and surface-Printing Polyester with Cotton Round Neck. Short Sleev T-Shirt(Custom Precision CNC Turning Lathe Processing POM Parts CNC Machining Plastic Parts,Frozen Food). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Good Quality R134A Refrigerant Copper Tube Fin Heat Exchanger), which can be one important cause of the increase in coagulant demand in algae-rich waters (Customized Plastic Injection Mould Products Industrial Parts Plastic Cross Pipe).High Speed Skateboard SKF 608 Hand Spinner Fidget Toy Bearing with Zz RS Seals(High Pressure Rubber Hydraulic Hose Assembly), particularly humic susbtances. Humic substances are highly negatively charged (High Bay Lighting Manufacturers), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (China Wholesale Hot Sale Microfiber Car Cleaning Towel). Maximal UV254removal was observed to be found around pH 6.0 (9-80V Laser Red Zone LED Work Safety Lights for Forklift Truck). The aquatic humic substances form complexes with dissolved aluminium species which are removed by adsorbing onto a solid, making the coagulation difficult in waters with both algae and humic susbtances (Triangle Plastic Checkout Counter Divider Bar with Logo Printed).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Stainless Steel Spiral Conveyor Systems Screw Transmission Conveyor.
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