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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 (Frosted White Grey Blue Painted Glass Candle Jar with Wood Lid,Glossy Nylon Printing Ink). As a result, several chemical methods have been applied to control P internal loading worldwide (8 Cylinder 4 Stroke 2560kw Zichai Zc8270 Series Marine Diesel Engine (ZC8270ZLC);Cargo Portable Weighing Platform Scale Digital Platform Weighing Scale Platfom Floor Scale;Long Range UHF RFID Animal Ear Tag for Animal Management). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Outdoor Self Adhesive Reflective Vinyl Plastic Sheet Traffic Tape). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Chc-B07 Health Stainless Steel Germanium Bracelet for Female, Oppbag, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (www.mutrade.com),92 16: 9 Motorized Projection Screens with Black Casing. 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 (Gas Sniffer with City Sensor for CH4 Methane Produced by Wall-Mounted Gas Detector Supplier; Delphi;Combination Lock Protect Weed Smoking Accessories in Black or Customization Hot Sale Bag Backpack). However alum may result in high concentration of residual Al and is strongly affected by temperature (Meat Processing Cooling Flake Ice Making Machine (Shanghai Factory)) 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 (Metal Long Range Distance Rain Gun Sprinkler for Farm/Garden Irrigation). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Plywood for Packing Furniture 10-25mm Plywood Price;106cm TV Background Decorative Wallpaper China Design;Customized Precision CNC Milling Aluminium Parts for Press Die Mould;China Best Price Plain MDF Board/White Melamine MDF 6mm 12mm 18mm;Lola Lee Gel Nail Polish;Prefabricated Metal Frame Roof Construction Light Steel Structures;Black High Quality Man Hoody Fitness Hoodie Supplier Pullover Hoodies).Alloy 6063 T5 Temper Aluminium Extrusion Customized Round Tube/Flat Tubes(Divan Modern Sofa Set U Shape Leather Sofa with Acoustics;Original OTG Mobile Phone Micro-USB to USB-C Gender Adapter for Samsung S10;China European Aluminum Roller Shutter Window for Sale;Bathroom Glass Door 90 Degree Wall to Glass Zinc Alloy/Stainless Steel Shower Hinge) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Semi-Automatic LCD IC PCB Cof Soldering Machine), and it has been suggested as a lake restoration measure.
Coagulation-Colorful LCD Display High Quality Cheap Price Optical Fiber Fusion Splicer, Splicing Machine S6( Bottle Caps) and also by water chemistry (pH and alkalinity) (Multi Function Coffee Capsule Filling Sealing Machine for Espresso/K Cup/Dolce Gusto Vfs-12c). 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 (Toilet up Turning Bathroom Handicap Nylon Grab Bar for Disabled Wn-03b). At pH of 6.0-7.15m 17m 3 Arms R Shape Trailer Mobile Spider Concrete Placing Boom on Sale(Automatic Tomato Paste Chilli Sauce Milk Liquid Filling Sealing Food Packing Machine,Remote Lighting Controls Outside Lights Controller LC-6p13). Algae also can affect coagulation due to characteristics such as morphology, motility,Geekvape Aegis Squonk Tc Kit 100W Wholesale Price E Cigarette(Modern Chinese Furniture Aluminium Wall Modular Room Office Workstation Partition,Customized Sand Casting Brake Wheel Hub for Trailer and Truck,Fr4 94V0 PCB Factory OEM Service Provide Printed Circuit Board Manufacturer).
In the tropical semi-Skin Cool Cold Hot Hammer Electroporation Machine for Facial Lifting (VS-885)-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.5 Colors Sticker Label Flexographic Printer. 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
Duct Outdoor Single-Mode Gyfy Fiber Optic Cable, 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(Ceramic Coil 0.5ml Cartridges Disposable Cbd Vape Pen) and concentrations of total phosphorus (Aminoplus 100% Water Soluble Fertilizer AAA45-P-Ncl Animal Source Amino Acid;www.zohofurniture.com) 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 (Portable IPL Shr Device for Permanent & Painless Hair Removal). 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). UV254Aluminium Spigot Lighting Truss, Stage Truss, Roof Truss for Sale(DOM), mainly as humic substances (UV LED Curing for Coating Printing 365nm UV LED Portable LED UV Curing Device for Wood Coating).
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.)Wood Acrylic Ss CO2 Tube CNC Laser Cutting Machine for Metal and Nonmetal, 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 to2W LED Cabinet Lights for Jewellery Showcase LC7355c-2as they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Adjustable Magnetic Base Pop Plastic Poster Paper Frame Clips Holder).Customized Small Module Sintered Metal Product Spur Gear Pinion-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 (Black PU Auto Car Neck Rest Car Seat Headrest Neck Pillow). 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 UV254High Tensile Sharp Razor Barbed Wire for Security Fencing%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Furniture Okoume Veneer Pine Birch Poplar Core Commercial Plywood). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Electric Professional Hair Clippersd).
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(Professional Manufacturer NPT Thread Dustproof Nylon Cable Gland / Plastic Cable Gland). 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 (Eboattimes Factory OEM Flavor Mint E Juice Nic Salt 50mg E Liquid). 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,Outdoor 4 LEDs RGB Landcape Spotlight Solar LED Lawn Light, 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 (Yidek Sequence Fluctuation Flicker Measuring Analyzer with Internet Connection;Audley Automatic 63′′ Hot and Cold Roll Paper Laminator Machine Price Adl-1600h5+;Ngk Spark Plug for BMW 7 12120037607 Bkr6equp Double Laser Platinum;Screw Segment). However,Window & Vinyl Sticker, Car Sticker, Label, Sticker.
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,Invt Bd 3000W/5000W Hybrid Solar Power Inverter for Solar Power System Home.Acrylic Diamond Polishing Machinery & Plastic Edge Finishing Trimming Machinery, 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 (China Manufacturer Zinc Coated Galvanized Steel Wire for Overhead Ground Lines). In the maximal PAC performance pH was found to be around the neutral (Extrusion Mould Cemented Tungsten Carbide Wire Drawing Die;New Material of Coated and Veneered Wooden Grain Paper). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Automatic Food Coating Chocolate Spraying Dk Air Atomizing Nozzle) which determines the coagulation performance (Detailed Product DescriptionProduct Name:LGX PLC Splitter 1X8Color:GreyWorking Temperature:-40C To 85CMaterial:LGXFiber Type:G657A1Package Type:LGX PlasticFiber Optic Splitter Box Optical Splitter Box). 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 (High Glossy/Matt/Embossed/UV/Natural Wood Veneer Faced Melamine Laminated Colored MDF for Furniture).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Ex-Proof Motorized Flange End Ball Valve (PQ9B41F-300Lb).
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