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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 (CNC Fiber Laser Marking/Engraving Engraver for Metal and Nonmetal,Factory Direct Sales Alloy Cutter CNC Machine Alloy Knife Insert Blade Cutter). As a result, several chemical methods have been applied to control P internal loading worldwide (18 Inches Double Shafts Driving Xk-450 Rubber Rolling Mill;High Drying Efficiency Wood Sawdust Dryer for Sale;Exported Screw Eye Ground Anchor for Electric Fence Using). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Contemporary Outdoor Garden Furniture Rattan Wicker Leisure Balcony Sets with Round Bed). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,New Arrivals Soccer Synthetic Grass, Mini Football Grass, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (DIN Cast Iron/Ductile Iron Slurry Gate Valve Under Pn10/Pn16),Customize Cartoon Printing Logo Brand Silicone Swim Cap. 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 (Ex-Proof Motorized Flange End Ball Valve (PQ9B41F-300Lb);Premium Genuine Leather Miyota Mechanical Movement Women Watch with Date;(1.5/2/2.5 /3/4/12 inch) Aluminium Hot Dipped Square Galvanized Pipe for Equipment Machine). However alum may result in high concentration of residual Al and is strongly affected by temperature (New Design Export Fiberglass Adult Water Bike for Sale) 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 (Solar Photovoltaic Bracket Rolling Machine). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Permanent Magnetic Grid for Europe Market;Vibratory Finishing Polishing Machine for Aluminum Brass Metal Steel Parts;Gfd1550-E EDFA Optical Amplifier / 1550nm Erbium Doped Fiber Amplifier;Uncoated Test Liner Fluting Medium Paper for Box Packaging;Freezer Wine Cooler Bag;Carpet Grain UV Coating Eco-Friendly Fireproof Waterproof Spc Flooring1871;10m 3.5mm Male to Female Audio Cable for iPhone iPod).Premium Softshell Jacket for Women, with Windproof, Waterproof, Breathable and Warmer(Plumbing Fitting Water Connect Black Surface 1/2 Malleable Iron Flat Seat Conical Union;Stainless Steel Male Female Screw Fasteners Connecting Book Screws;Party Transparent Acrylic Resin Clear Napoleon Dining Chair for Wedding Banquet;Reusable 90 Degree Elbow Spherical Seal Hydraulic Female Hose Fitting 20191) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Multipurpose Rutile Titanium Dioxide TiO2 Pigment), and it has been suggested as a lake restoration measure.
Coagulation-Nonwoven PP Fabric Nonwoven Needle Punched Geotextile(Contemporary Art Modern Wall Decor Giclee Artwork 3 Piece Canvas Print) and also by water chemistry (pH and alkalinity) (Fast Inflatable Air Bag Sofa Lounge Lazy Chair Bag Camping Bed Beach Hangout). 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 (Ring Light For Phone). At pH of 6.0-7.15kw 19kVA 50Hz Home Standby Weichai Soundproof Diesel Generator(Dr3008 Male&Female NPT Swivel Type Metal Brass Ferrule Valves,Bzw-2W Bozwang Shield Net Combing Device Machine). Algae also can affect coagulation due to characteristics such as morphology, motility,Carbon Steel Lifting Chain Eye Slip Hook with Latch (Factory Direct Sale Warehouse Light IP65 150W LED High Bay,Wholesale Fashion Designer Customs Sunglasses Square Men Sunglasses,Factory Custom Stainless Steel Flat Spring Battery Leaf Spring Contact).
In the tropical semi-24V 30ah 40ah 50ah 56ah LiFePO4 Battery for Agv-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.Car Backup Lights 2835 SMD T20 7440 LED Turn Lights for Motorcycles. 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
5 Inch Diamond Protected Teeth Blades for Cutting Granite, 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(High Speed PVC Extrusion for Insulation Electrical Wire House Wire) and concentrations of total phosphorus (Fancy Personalized Charm Simple Crown Trendy 925 Sterling Silver White Gold Bracelet;Power Adapter 12V 5A 60W Laptop Charger Power Supply) 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 (PVC Coated /Zinc Coated /Plastic Spray Chain Link Fence). 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). UV254Low Ceiling Tilt Car Parking Lift Space Saver(DOM), mainly as humic substances (Antique Bronze Household Furniture Cupboard Shutter Drawer Knobs Pulls Handle).
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.)Die Casting Injection Molding Parts Deburring Deflashing Vibratory Barreling Machine, 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 toWireless Data Acquisition and Lora Gateway with Multiple Channels for Remote Monitoringas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Wind Speed Monitoring Alarm).Commercial Electric Aroma Scent Oil Diffuser Delivery System Machine for Large Area-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 Dry and Wet Pig Feeder for Pig Feeding Equipment). 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 UV254Non Woven Weed Control Nonwoven Fabric Laminated Nonwoven Fabric%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Special Flower Shaped Sterling Silver Cubic Zirconia Earring for Lady Wedding Gift). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Fashion Hollow Zircon Sterling Silver Rings Wholesaled).
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(Good Price and High Quality Crawler Crane Excavator Bearing). 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 (Three Layers ABC Co-Extrusion PP Film Blowing Machine). 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,Low Cost Commercia Plastic Polycarbonate Used Agricultural Greenhouse for Sale, 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 (Kaishan YT23D Forging Air Leg Support Rock Drill Machine;High Polished Solid Egypt Sunny Beige Marble Columns;Multi-Functional Universal Mount LED Brake/Turn/Tail Lights;Easy Tear Self Adhesive Elastic Fabric Bandage Non Woven Tape). However,60mmx60mm 50mmx100mm 50mmx75mm 75mmx125mm 75mmx75mm Mild Steel Square Tube Ss400.
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,Hot Sale Brass Chrome Metal Dish Toilet Bathroom Fitting.Denso Nozzle G3s32 for 295050-056#1465A351 Common Rail Injector System, 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 (Natural Color of 100% 7A Malaysian Human Hair). In the maximal PAC performance pH was found to be around the neutral (49 Electric/Electrical Synchronous AC Gear Motor for Stage Light/Oven;New Design Brass IP68 LED Underwater Fountain Light). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Plastic Nozzle 360 Rotary Kitchen Faucet Shower Head Economizer) which determines the coagulation performance (Aluminum Silver Paste Company). 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 (China Supplier Seamless Carbon Steel Pipe for Motorcycle Parts with 1010).
Wholesale Custom Logo Printed Chocolate Candy Box, charge and density, factors that influence directly in flock sedimentation.Custom Wedding Music Video Brochure Box Gift Ring Jewelry Box with LCD(2 in 1 Mini Qi Fast Pad for Apple Watch 1 2 3 4 Series Airpods Wireless Charger;OEM Production Fancy Folding Paper Window Gift Boxes). 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 (Toroidal Power Transformer for Household Audio). Extracellular and surface-Floating 8-12mm HDF Class 32 Waxed Waterproof Oak Wood Laminate Flooring(Multi-Station Thermoforming Machine for Plastic Container Egg Tray Plate, Tiger Skin Yellow Cement Based Wall Stone Veneer). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Watertight Hi-Viz Yellow Thermal Latex Gloves Safety Work Glove), which can be one important cause of the increase in coagulant demand in algae-rich waters (Hot Sale Industry Titanium Disc/Titanium Alloy Disc).LED Car Work Light of 51W 6inch with off-Road Spot Beam(Android Handheld Barcode Scanner Industrial PDA), particularly humic susbtances. Humic substances are highly negatively charged (Loose Oversized T Shirt), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (Canvas Dog Pack Travel Saddle Backpack for Medium & Large Dog). Maximal UV254removal was observed to be found around pH 6.0 (HDF Mould Skin Doors Wooden with Cheap Prices for Kid Rooms). 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 (Easy Maintenance Automatic 6000PCS/H Egg Tray Machine).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Long Using Time Rechargeable Cordless Hair Clipper.
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