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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 (Large Outdoor Water Park Slide/Water Turntable Amusement Equipment,New Small Wheel Loader Backhoe Wz30-10 Price for Sale). As a result, several chemical methods have been applied to control P internal loading worldwide (Pond Electric Copper Wire Clean Water Pump with European Plug;Customized Disposable BBQ Bamboo Round Stick and Skewers.;Wholesale Custom Microfibre Towel Rack Cooling Gym Yoga Bath Towel). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (High Quality Honeycomb Ceramic Proppant / Filter Catalyst Supported for Mechanical Equipment). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Stainless Steel Juice Multi-Bag Filter Machine, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Android 7inch Industrial Panel Computer Capacitance Screen),Linear Rail Guide/Linear Guide Way Bearing/Hiwin Mgn12h Linear Guide. 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 (Pet Plastic Sheet Extrusion and Cup Lid Food Tray Container Forming Machine Production Line;CNC Fiber Laser Marking/Engraving Engraver for Metal and Nonmetal;18 Inches Double Shafts Driving Xk-450 Rubber Rolling Mill). However alum may result in high concentration of residual Al and is strongly affected by temperature (High Drying Efficiency Wood Sawdust Dryer 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 (Lcd Display 2.8 Inch). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Exported Screw Eye Ground Anchor for Electric Fence Using;Contemporary Outdoor Garden Furniture Rattan Wicker Leisure Balcony Sets with Round Bed;Ex-Proof Motorized Flange End Ball Valve (PQ9B41F-300Lb);Premium Genuine Leather Miyota Mechanical Movement Women Watch with Date;70cm Rangehood;(1.5/2/2.5 /3/4/12 inch) Aluminium Hot Dipped Square Galvanized Pipe for Equipment Machine;New Design Export Fiberglass Adult Water Bike for Sale).Factory Price Rotary 1530 4 Axis CNC Router for Promotion(Permanent Magnetic Grid for Europe Market;Vibratory Finishing Polishing Machine for Aluminum Brass Metal Steel Parts;12v Power Supply Pcb;Gfd1550-E EDFA Optical Amplifier / 1550nm Erbium Doped Fiber Amplifier) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Uncoated Test Liner Fluting Medium Paper for Box Packaging), and it has been suggested as a lake restoration measure.
Coagulation-Forged Lifting Load Hanger Clevis Sling Hoist Hook(Carpet Grain UV Coating Eco-Friendly Fireproof Waterproof Spc Flooring1871) and also by water chemistry (pH and alkalinity) (10m 3.5mm Male to Female Audio Cable for iPhone iPod). 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 (Solar Irrigation Valve). At pH of 6.0-7.Anti Humidity Machine Dehumidifier, Portable Home Dehumidifier for Whole House(Plumbing Fitting Water Connect Black Surface 1/2 Malleable Iron Flat Seat Conical Union,Stainless Steel Male Female Screw Fasteners Connecting Book Screws). Algae also can affect coagulation due to characteristics such as morphology, motility,Cotton/Polyester/Spandex Interlock for Clothing(Reusable 90 Degree Elbow Spherical Seal Hydraulic Female Hose Fitting 20191,Multipurpose Rutile Titanium Dioxide TiO2 Pigment,Hotel Cotton Quality Bathroom Rug Made in China (JRD251)).
In the tropical semi-Wallbox EV Charging Station with Ce Approvals-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.Srz Industrial Radiator, SRL Steel-Aluminium Composite Radiator, Srq Steam Tube Radiator. 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
OEM Metal Iron/Carbon/Steel Hammer Forging for Cylinder/Raiway Wheels, 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(Dr3008 Male&Female NPT Swivel Type Metal Brass Ferrule Valves) and concentrations of total phosphorus (Bzw-2W Bozwang Shield Net Combing Device Machine;Cake Shovel) 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 (Disposable Non-Vented Spin Connector IV Giving Infusion Set with Needle Luer Slip Lock Air Vent). 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). UV2544.3 Inch TFT LCD Car Video Monitor Camera Video Parking System(DOM), mainly as humic substances (Wire to Board Spring Type Connector Sy141-2.54mm Made in China).
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.)High Efficiency Complete Italy Pasta Production Line, 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 toPVC Coated Galvanized 12 Guage Iron Baling Wireas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Moon Metal Stamp Monogram Stamp Mild Steel Fabrication Michaels Metal Stamping Metalstamp Inc).Monofilament Fibrillated Twist Wave Polypropylene Fiber PP Fiber for Concrete-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 (Mt-5113s Digital Textile Sublimation Inkjet Printer Solvent Printer for Transfer Paper Wood). 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 UV254LED IP65 Outdoor Light T8 Fluorescent Tube Lighting Fixture%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Custom PC 3m Adhesive Electrical Device Embossing Membrane Switch Panels). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Ultrasonic High Quality Facial Cleansing Brush Anti-Wrinkled).
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(Wireless Data Acquisition and Lora Gateway with Multiple Channels for Remote Monitoring). 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 (Cheaper Polyester Cord Strap Factory Made in China). 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,Tractor/Driving Truck/Bus/Special Car/Excavating/Excavator/Bulldozer Transport Low Bed Semi Trailer, 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 (Special Flower Shaped Sterling Silver Cubic Zirconia Earring for Lady Wedding Gift;CNC Machining Part CNC Turning Stainless Steel Parts Aluminum CNC Milling;Good Price and High Quality Crawler Crane Excavator Bearing;35X35 ASTM A36 Hollow Section/Square Steel Pipe). However,4 Drawer Steel Office Vertical Filing Cabinet.
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,Adjustable 2g/H Quartz Tube Ozone Generator Ozone Water Purifier.Healthcare Product Compression Wrap Thigh Hip Brace Groin Support Brace, 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 (Three Layers ABC Co-Extrusion PP Film Blowing Machine). In the maximal PAC performance pH was found to be around the neutral (Aluminium Silver Lifter 230kg Suction Heavy Duty Suction Cup Hand Tool for Glass;Galvanized Razor Barbed Wire with Ce and SGS for Livestock Farm). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Kaishan YT23D Forging Air Leg Support Rock Drill Machine) which determines the coagulation performance (TPE flexible cables). 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 Polished Solid Egypt Sunny Beige Marble Columns).
Surgical Drape Angio Pack Angiography Drape Pack, charge and density, factors that influence directly in flock sedimentation.Dry Ice Production Block Cube Maker Producer Refrigeration Industry Use Machine(Multi-Functional Universal Mount LED Brake/Turn/Tail Lights;Natural Color of 100% 7A Malaysian Human Hair). 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 (49 Electric/Electrical Synchronous AC Gear Motor for Stage Light/Oven). Extracellular and surface-Silicon Carbide Mechanical Seal with Excellent Corrosion Resistance(Flat Dimmable 48W 600X600mm LED Ceiling Panel Lighting with 3years,New Design Brass IP68 LED Underwater Fountain Light). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Plastic Nozzle 360 Rotary Kitchen Faucet Shower Head Economizer), which can be one important cause of the increase in coagulant demand in algae-rich waters (China Supplier Seamless Carbon Steel Pipe for Motorcycle Parts with 1010).Auto Parts 3 Points Elr Seats Belts Safety Belts Automotive Belt(2 in 1 Mini Qi Fast Pad for Apple Watch 1 2 3 4 Series Airpods Wireless Charger), particularly humic susbtances. Humic substances are highly negatively charged (Replacing Laminate Flooring), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (OEM Production Fancy Folding Paper Window Gift Boxes). Maximal UV254removal was observed to be found around pH 6.0 (Toroidal Power Transformer for Household Audio). 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 ( Tiger Skin Yellow Cement Based Wall Stone Veneer).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.NEMA 14 High Frequency Low Noise Stepper Motor (35SHD0001-15).
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