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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 (Sports Bra Shock-Proof Gathering Stereotypes Bra,10102-71-3). As a result, several chemical methods have been applied to control P internal loading worldwide (2000W 10mm Stainless Steel Mild Steel Fiber Laser Cutting Machine Price;Stainless Steel Mesh Screen Automatic Self-Cleaning Filter;Hot Sale 250ml Green Dorica Glass Olive Oil Bottle). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (7). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Farm Seed Spreader / Tractor Fertilizer Spreader for Sale, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Lube Oil Polishing System to Improve Color Grade (TYR series)),HVAC Connected Large Area Scent Diffusion System with 2 Bottle. 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 (Factory Stocked 500ml Double Wall Plastic Glitter Water Bottle Diamond Lid Insert Layer;High Quality Cheap Custom Small Kids Exercise Outdoor Playground with Slide;Round Vibrating Separator Machine - Round Vibratory Sieve). However alum may result in high concentration of residual Al and is strongly affected by temperature (600ml Travel Sports Bicycle Water Bottle (HBT-037)) 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 (Communication). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Shielded Mini Ball Bearings with Anti-Rusty Stainless Steel Smr106zz;OEM Aluminum Housing Fuel Filter Housing for Truck/Train Parts;Telescopic Chenille Microfiber Double Sides Flat Mop for Easy Cleaning (1014);Stainess Steel Handheld Type Pedb-400A Fiber Laser Marking Coding Machine Systems;Custom Shaped Aluminum Foil Plastic Cosmetic Sachet Bag for Facial Mask;Frosted White Grey Blue Painted Glass Candle Jar with Wood Lid;8 Cylinder 4 Stroke 2560kw Zichai Zc8270 Series Marine Diesel Engine (ZC8270ZLC)).100W/150W/200W Industrial High Bay UFO LED for Tennis Court Lighting(Cargo Portable Weighing Platform Scale Digital Platform Weighing Scale Platfom Floor Scale;Long Range UHF RFID Animal Ear Tag for Animal Management;Oneprint 1.6m 1.8m 3.2m UV Roll to Roll UV LED Printer UV-1600 UV-1800 UV-3200 for Hot Selling;Outdoor Self Adhesive Reflective Vinyl Plastic Sheet Traffic Tape) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Gas Sniffer with City Sensor for CH4 Methane Produced by Wall-Mounted Gas Detector Supplier), and it has been suggested as a lake restoration measure.
Coagulation-Rainbow Rafting Fiberglass Aqua Water Park Slide( Delphi) and also by water chemistry (pH and alkalinity) (Combination Lock Protect Weed Smoking Accessories in Black or Customization Hot Sale Bag Backpack). 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 (Smokeless Carbonizer Wood Sawdust Activated Carbon Charcoal Making Machine). At pH of 6.0-7.Lab Pipette Tips with Good Quality Low Price(Meat Processing Cooling Flake Ice Making Machine (Shanghai Factory),Plywood for Packing Furniture 10-25mm Plywood Price). Algae also can affect coagulation due to characteristics such as morphology, motility,Factory Nitrogen Fertilizer Ammonium Sulphate 21%N Steel Grade for Agriculture(106cm TV Background Decorative Wallpaper China Design,Customized Precision CNC Milling Aluminium Parts for Press Die Mould,Colorful Enteric Gelatin Coated Empty Capsule Size 2).
In the tropical semi-Jmc Vacuum Road Dust Truck Mounted Sweeper Car-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.Reflective Tape Protective Nomex Fire Suit with Trousers. 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
RF Wrinkle Removal IPL Hair Removal Skin Rejuvenation Beauty Salon Equipment with Filter, 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(Black High Quality Man Hoody Fitness Hoodie Supplier Pullover Hoodies) and concentrations of total phosphorus (Divan Modern Sofa Set U Shape Leather Sofa with Acoustics;Customized Auto Parts Metallization Planting Chrome Ceramics Film PVD Coating Machine) 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 (Semi-Automatic LCD IC PCB Cof Soldering Machine). 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). UV254Multifunctional RF/40K Body Vacuum Roller Weight Loss Beauty Salon Cavitation Beauty Equipment(DOM), mainly as humic substances ( Bottle Caps).
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.)Best Brush Customized Synthetic Flat Foundation Makeup Brush Professional Cosmetics Accessory, 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 toModern Chinese Furniture Aluminium Wall Modular Room Office Workstation Partitionas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Temperature Controlled Meter).Continuous 1-4 Lines Cij Batch Number Automatic Industrial Inkjet Printer-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 (Kitchenware BBQ Grill Mat Toaster Oven Liner for Bakeware). 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 UV254Custom Printed Sublimation Printing Fit Yoga Pants Leggings%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Ceramic Coil 0.5ml Cartridges Disposable Cbd Vape Pen). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Vinyl PVC Outdoor Advertising Flex Mesh Banner Display Perforated Fabric Design Printing Mediad).
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(Digital Printing Pillow for Sofa with Metallic Printing). 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 (Androst 3 5 Dien 7 17 Dione Raw Steroid Powders Fat Burning Prohormones CAS 1420-49-1). 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,Customized Wholesale Waterproof Crossbody Chest Bag Backpack Sling Bag Women Messager Shoulder Bag, 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 (Kh CNC Plasma Cutting Machine 1530 CNC Controller;Automatic Brake Pad Brake Shoe Shrink Packaging Machine; Forged Steel Rings for Large Diameter;www.ironwiremeshfactory.com). However,Bonding Strength Testing Machine Servo Control Universal Tensile Strength Tester.
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,Licensed Mercedes-Benz Gtr 2 Seats Children Car in Black.7, 5kw High Effficient AC Motor as EV Conversion Kit, 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 (2W LED Cabinet Lights for Jewellery Showcase LC7355c-2). In the maximal PAC performance pH was found to be around the neutral (Osyea 2019 Outdoor Power Solar Garden LED Street Lamp;Precision Inline Oil Filter Element EMS2000). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Black PU Auto Car Neck Rest Car Seat Headrest Neck Pillow) which determines the coagulation performance (Carbide Planer Insert). 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 (Furniture Okoume Veneer Pine Birch Poplar Core Commercial Plywood).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Commercial Coffee Roasters for Sale 1kg 3kg 6kg 12kg 120kg Coffee Roaster Machine Manufacturer.
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