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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 (Mobile Phone Jammer + WiFi / GPS / 4G Jammer 6 Bands,China Pcb Circuit Board Design). As a result, several chemical methods have been applied to control P internal loading worldwide (Professional Korea Hifu Focused Ultrasonic Beauty Machine for Wrinkle Removal;Durable Life Stainless Steel Knotted Cable Mesh;Bamboo Rattan Stick / Aroma Rattan Stick/Nature Reed Rattan Stick). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Customized Wholesale Waterproof Crossbody Chest Bag Backpack Sling Bag Women Messager Shoulder Bag). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Eye Bolt Screw Stainless Steel Fastener for Aluminium Profiles, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Cable Manufacturer PVC Wire and Cable Plastic Extruder),Used Komatsu PC60-7 Crawler Excavator Komatsu 6ton Mini Digger for Sale. 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 (Light Weight FRP XPS Composite Panel for Mobile Home Construction;OEM Metal Iron/Carbon/Steel Hammer Forging for Cylinder/Raiway Wheels;Butterfly Pn16 CF8m Water Dual Flap Flapper Type Wafer Check Valve). However alum may result in high concentration of residual Al and is strongly affected by temperature (Auto Parts 3 Points Elr Seats Belts Safety Belts Automotive Belt) 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 (Ozone Generating Air Purifiers Ozone Generator for Sterilization Air). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Gdg24 0.55kw 550W 0.75HP 24L Oil Free Air Compressor;Seu 2*8 AWG Concentric Service Entrance Cable;Acrylic Crystal and Enamel Flamingo Bracelet Fashion Jewelry;130lm/W LED High Bay UFO Lamp Fixture with Different Watts 100W 150W 200W;Factory 0.3mm Natural Africa Okoume Face Veneer;Auto Electric Car Step Siliding Step with Ce Load 250kg;China Manufacturer Cement Plaster Storage Pressure Tank Container).Handles Operated Cast Iron EPDM Seat Wafer Butterfly Valve(China Automatic Round Stainless Steel Bar Peeling Lathe Machine;Fabric/ Cloth Insertion SBR/ EPDM/ Nitrile/ Neoprene/ FKM/ Natural Anti-Slip Rubber Flooring;Elegant Wall Mounted Metal Garment Display Rack for Ladies Clothes Shop Design;Activated Carbon Pellet Manufacturer Used for Gas Treatment) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Custom High Quality CNC Milling Acrylic Block Stainless Steel Aluminum CNC Precision Milling Service), and it has been suggested as a lake restoration measure.
Coagulation-DC Colorful Battery Operated Small Hand Fan for Outdoor Use(Auto Starter 0001230002 12V 3.0kw 11t for John Deere) and also by water chemistry (pH and alkalinity) (Fashion Italian Style Hotel Furniture Wooden Marble Dressing Table). 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 (Dapeng Laser Ep Fiber Laser Marking Machine for Metal Color Engraving). At pH of 6.0-7.Heavy Duty Cast Ductile Iron Manhole Cover with Concrete Infill, Solid Top, for Sewer, Stormwater(New Product High Quality Home Smart Wireless Video Doorbell Camera,Hot Sale Ding Chair Fabric Quality China Anji Bar Stool Supplier). Algae also can affect coagulation due to characteristics such as morphology, motility,Plastic Round Home Storage Box Vacuum Insulated Lunch Box(1kVA/2kVA/3kVA/4kVA/6kVA/8kVA/10kVA/15kVA/20kVA/30kVA Single Phase Online UPS,12oz Dispossable Ripple Wall Paper Cup with Good Insulation,Ce Certificate Plywood Veneer Lathe Manufacture).
In the tropical semi-Jarliet 140cm Big Breast Mini Sex Love Doll for Men Sex Masturbation-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.HDPE Vented Nestable and Stackable Plastic Fruit Vegetable Crate for Storage. 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
Five Brushes Car Wash Rollover Car Washing Wholesale, 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(Double Breasted Wool Casual Long Kid Girl Coat Winter Fashion Jacket for ODM OEM) and concentrations of total phosphorus (Luxury Fashion Lady Women Shoulder Tote Bag Leather Evening Handbag;Baby Pvc Waterproof Rain Apparel) 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 (Kynko Li-ion Cordless Drill with 18V Battery (KD30)). 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). UV254Customized High Performance Industrial Oil Hydraulic Cylinder for Metallurgical Industry(DOM), mainly as humic substances ( Radio etc Use.).
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.)Large 25X100m Exhibition 2500 Seat Tent for Trade Show, 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 toGood Price Automatic Kitchen Towel Tissue Paper Rewinding Machineas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Auto Spare Parts Mn195616 Ignition Coil for Mitsubishi).Narrow Hub Connection Brake Discs for Sprockets (TLK603 RLK603 55X110)-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 (Dn630mm Plastic Pipe Butt Fusion Welding Machine). 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 UV254Spiral Flat Metal Pot Scourer for Kitchen Cleaning Ball%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Manufacturer Vertical Turbine Fire Pump 1HP Inline Fire Pumps). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Guest Chairsd).
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(12 PCS CRV 1/2 Dr. Socket Set for Car Repair Tools). 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 (Invt Bd 3000W/5000W Hybrid Solar Power Inverter for Solar Power System Home). 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,Cooling Water Chemicals Scale Inhibitor and Corrosion Inhibitor for Power Plant, 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 (Han Star 3015 1000W/1500W Fiber Laser Cutting Machine Laser Cutter for Carbon Steel Pipe/Tube Low Price;3-Axle 30mt LPG Haulage Truck Trailer Depot Gas Transportation Tanker;Heavy Duty Cast Ductile Iron Manhole Cover with Concrete Infill;Cnc Profile Bending Machine High Quality Supplier). However,Panasonic Ai Spare Parts X004075 with Large Stock.
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,Light Controller DMX Controller for Stage Light.2019 Fashion Women Hot Red All The Rage Skater Party Cocktail Dress, 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 (Agriculture Cultivator Springs Double Spring Tines 3.5-12mm). In the maximal PAC performance pH was found to be around the neutral (Wholesale Price DC12V 2835 S-Shape/Zigzag LED Flexible Strip;Wholesale High Quality USB Charging Data Cable for Original Apple iPhone 7 Charger Cable). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Printed Circuit Board Mobile Charger PCB Board LED PCB Board Module) which determines the coagulation performance (Professional OEM Factory Laundry Washing Detergent Powder). 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 (Long Service Life Smooth Lead Screw Tr3.5X0.61).
1/2 CRV Industrial High Quality Quick Release Ratchet Handle Wrench, charge and density, factors that influence directly in flock sedimentation.Strong Bleach Ability Activated Bleaching Earth/Fuller Earth for Vegetable Oil Decoloration(Computerized CNC Turning Machine Metal Lathe Price Ck63L;8mm PVC Coated Galvanized Steel Wire Rope for Lifting). 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 (Manufacture RP HP UHP Graphite Electrode 300mm 350 with Nipples for Smlting). Extracellular and surface-Bae502 Factory Direct Hospital Furniture Electric Medical Equipment Bed(CNC Automatic Steel Coil Forming Machine with Ce Certificate,Good Quality UPS Batteries 12V 65ah for Burglary Protection System). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Stainless Steel/Brass/Copper/Carbon Steel Woven Wire Mesh with ISO Approved for Filtration), which can be one important cause of the increase in coagulant demand in algae-rich waters (Stainless Steel Tube Electric Heater Industrial Immersion Cartridge Heater).1.2344/AISI H13/JIS SKD61 Mould Steel for Die Casting(Wholesale Events 6FT Wood Dining Round Table), particularly humic susbtances. Humic substances are highly negatively charged (Wood Decorative Mouldings), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles ( Wall Fan 3 in 1-Competitive Price). Maximal UV254removal was observed to be found around pH 6.0 (CNC Router 2030 3D CNC Foam Rubber Gaskets Oscillating Knife Leather Cutting Machine). 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 (High Quality Tungsten Carbide Gripper Inserts for Chuck Jaws).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Bathroom Furniture Integral Solid Surface Stone Shower Stool Shower Seats.
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