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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 (Floor Stainless Steel Fix Movement Joints Decorative Stainless Steel Tile Trim,Antibacterial Bamboo Cutlery). As a result, several chemical methods have been applied to control P internal loading worldwide (Custom Printing Luxury Magnetic Closure Paper Gift Box Cosmetics Watch Boxs Guangdong; Flour Mill Machine;Cross-Border Jewelry Hot Silver Set Diamond Full Diamond Crown). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Zirconia Metal Grinding Abrasive Mini Flap Disc Sanding Disc). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Custom Mono 0.96 Inch Mini Monochrome 128X64 Small OLED Display, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Flake Ice Maker),Industrial Coal Fired 8 MW Hot Water Boiler Factory Price. 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 (Amazon Top Seller Double Wall Thick Bottom Glass Water Bottle with Fruit Infuser; Restaurant Kitchen Used Lift;Customized Metal Forge Machinery Wrought Iron/Steel/Aluminum Drop/Open/Die Forging). However alum may result in high concentration of residual Al and is strongly affected by temperature (2018 Newest Design More Quiet Plastic Home Mini Dehumidifier with 1.3L Water Tank) 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 (Robotic Bus/Truck Wash Machine/Car Washing Machine with Super Big Brushes). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Beautiful Design Coral Fleece Terry Towel Set;Lx85-9m Wheeled Digger Digging Height 6536mm 8 Ton Mini Wheel Wood Grabber;Clear Lens of CHP CO2 Laser Protection Goggles for CO2 Laser Beauty Equipment with Frame36;Genuine 1m USB Date Charging Cable for iPhone;HDF Lamiante Floor Home and Office Wood Laminate Flooring;Filter Fiber Car Engine Cabin Air Filter for Mazda; Customized Available).Stainless Steel Bimetal BBQ Gas Bimetal Oven Thermometer(Vulcanized Fiber Paper Electrical Insulation Paper;2019 Wholesale 6.5HP 300kgs Mini Dumper Crawler for Agriculture;Precast Concrete Segment Mould;on-Line Aoi Machine for Inspection Post Reflowing or Placement (A2000)) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Double Station Pesticide HDPE Bottle Making Machine), and it has been suggested as a lake restoration measure.
Coagulation-27.5′′ Lithium Battery Mountain Style Electric Bike(Multifunction Trolley Luggage Bag Travel Luggage Men′s Trolly Luggage with 4 Wheels) and also by water chemistry (pH and alkalinity) (Steel Fabrication Part Custom Steel Sheet Metal Fabrication Work). 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 (High Quality Rectangular Carbon Rod/Electrode B5520). At pH of 6.0-7.Marine Salvage and Refloatation Rubber Airbag Roller Bags(Customerized Demo Prototype with Surface Treating for Exhibation (LW-02189),M2m Outdoor Wi-Fi Outdoor CPE DTU with Dual LAN Ports). Algae also can affect coagulation due to characteristics such as morphology, motility,Girls Unicorn Costume Party Dress Tutu Kids Cute Flower Princess Pageant Carnival Clothes(Spare Customizable Pultrusion FRP Angle Bar for 50*50*2.8mm,Desktop Fiber Laser Cutter 1390 Cheap Price 800W/1000W,Automatic Vertical Tooth Pick Injection Molding Machine).
In the tropical semi-Glass Charger Plate Decoration Plates Shining Gold Rim Clear Charger Plates-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.Stainless Steel Mesh Screen Automatic Self-Cleaning Filter. 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
China Supply High Quality MIFARE® DESFire® EV1 2K/4K/8K RFID White PVC Card, 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(Online pH TDS Ec Controller Digital Electrical Conductivity Meter) and concentrations of total phosphorus (Rechargeable Battery Powered Indoor WiFi Camera with Custom APP;qj-ec.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 (2019 New Arrival Original Adaptive Fast Adapter Rapid Wall Charger for Samsung S10). 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). UV254AISI ASTM 409 410 420 430 440 Cold Rolled Stainless Steel Coil(DOM), mainly as humic substances (Luxury Office Furniture Artificial Stone Solid Surface Computer Office Table).
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.)Semi-Automatic Hydraulic Leather Football 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 toModern Style Home Furniture Set Metal Stainless Steel Outdoor Kitchen Furnitureas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(28mm Marine Plywood for Shipping Container Flooring Use Shipping Container Parts).Decorative Polyester Board Rocplex, Polyester Plywood-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 (China Homemade Bearing Ball Screw for CNC (DFU series 16-100mm)). 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 UV254Car Air Compressor Tire Inflator Pressure Gauge%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Pneumatic Ef Series Air Preparation Units Filter). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Block Chaind).
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(Concrete Grinding Plate for Abrasive Machines of Abrasive Disc). 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 (5 pins grey black blue plastic connector straight plug INT- PAG. M0.5GL. AC52A/G/J/N/R/V/B). 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,Hot Selling Polyresin Garden Dark Blue Birdhouse for Tree Decoration, 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 (Popular Environmental Plastic Vinyl Spc Floor Tile;Eastcooler 10X2.5 Water Filter Granular Active Carbon Filter Cartridge;18650 Cylinder Cell Case with Anti-Explosive Cap and Insulation O-Ring;All In One Pc With Aluminum Alloy Case). However,Dac34640037 Wheel Bearing /Automotive Bearing/ Hub Bearing.
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,Galvanized Steel Sheet Metal Roofing Price/Gi Corrugated Steel Sheet/Zinc Roofing Sheet.Good Quality Free Sample Bauxite Price Per Ton, 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 (Factory Price Chenille Sunscreen Sheer Fancy Curtain). In the maximal PAC performance pH was found to be around the neutral (Manufacture Leather Strap Japan Movt Stainless Steel Back Watch (cm19092);dual Row 15pin D-SUB Mechined PCB Mounting Power Connector). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Industrial Unit Cooler / Evaporative Air Cooler / Evaporator) which determines the coagulation performance (Respirator Mask For Smoke). 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 (Customized Aluminum Profile Extrusion with CNC Machining (ISO9001: 2008)).
Intelligent Auto Tracking Indoor Mini Camera Smart Life Tuya IP Camera, charge and density, factors that influence directly in flock sedimentation.Modular Concrete Batching Plant by Twin Shaft Mixer 3000/2000(Factory Supply Cheap Custom Bleached White Cotton Gloves;Hot Selling 2019 510 Thread 350mAh Vertex Battery). 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 (China Touch Screen for iPhone 6s LCD Touch Screen Digitizer). Extracellular and surface-Wholesaler HRC60 Carbide Corner Radius End Mills Chamferied Cutter(Disposable Manicure Kit,Srz Industrial Radiator). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (130kg/M3 Plastic PVC Core Foam for FRP Vacuum Infusion), which can be one important cause of the increase in coagulant demand in algae-rich waters ( Metal Duct Machine).High Quality and Low Price Aluminum Alloy Perforated Electrical Cable Tray(Reliable Shockproof Air Cushion Bubble Packaging Wrapping Roll Bag), particularly humic susbtances. Humic substances are highly negatively charged (Construction Galvanized Scaffold Steel Plank (FF-B008E)), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (Tungsten Carbide Milling Insert for Book Binding). Maximal UV254removal was observed to be found around pH 6.0 (PC Black Plastic Material Polycarbonate PC Granules Resin). 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 (3mm/0.4mm Honeycomb-Shaped Sound Absorbing Aluminum Composite Panel for Interior Decoration).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Colored Corrugated Steel Roofing Sheet with ISO9001.
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