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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 (Hydraulic Scrap Metal Baling Machine for Metal,Aluminum Foil Manufacture). As a result, several chemical methods have been applied to control P internal loading worldwide (Black Bracelet Leather USB Drive Free Design Logo;SS304 Stainless Steel Tube Rectangular/Square Tube;The Lowest Price 27er/29er Carbon Fiber Mountain Bike Bicicleta). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Hot Sale High Grade Popular Jacquard Curtain Fabric for Living Room/Bedroom). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,5 Inch Diamond Protected Teeth Blades for Cutting Granite, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (diagnostic ultrasound),Low Ceiling Tilt Car Parking Lift Space Saver. 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 (New Product Ideas Wooden Musical Jewelry Storage Box;21/24/27 Speed/ Aluminum Alloy Carbon Frame Mens Bicycle Manufacturer Bikes for Adult;Soft Tube Plastic Cylinder Round Bottle Screen Printing Machine Silkscreen Machinery). However alum may result in high concentration of residual Al and is strongly affected by temperature (Large Music Controlled Colorful Laser Water Fountain) 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 (Ck6140 Horizontal China CNC Lathe Machine with Optional Power Turret). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Anti-Corrosion Coated Line Pipe/Seamless Steel Pipe for Oil;1/2 CRV Industrial High Quality Quick Release Ratchet Handle Wrench;Wood Acrylic Ss CO2 Tube CNC Laser Cutting Machine for Metal and Nonmetal;SKF NTN Chik Koyo Deep Groove Ball Bearings 6308 Zz Ball Bearing Turbo for Sale 40*90*23mm;Car Led Fog Lights;Upal Cheap Folding Steel Gazebo Tent with PVC Fabric Roof;5r 200W LED Moving Head Beam 3 in 1 Stage Lighting).Die Casting Injection Molding Parts Deburring Deflashing Vibratory Barreling Machine(250ml Medical Transparent Ultrasound Ultrasonic ECG Gel Wholesale Price;Top Supplier Lcoe Cost Down 1500V Dual Glass 320W 330W 340W Poly Solar Panel;10 Ft T Post;Hybrid Power System 150kw Electricity Generating System with Battery Bank) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Customzied SKD11 Shear Blades for Leather and Plastic), and it has been suggested as a lake restoration measure.
Coagulation-Commercial Electric Aroma Scent Oil Diffuser Delivery System Machine for Large Area( Keyboards) and also by water chemistry (pH and alkalinity) (10kv Xple Heat Ahrinkable 1-Core Outdoor Termination Kit (Section 500~630 mm^2)). 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 (Zinc Alloy Die Casting Part). At pH of 6.0-7.Non Woven Weed Control Nonwoven Fabric Laminated Nonwoven Fabric(Aluminum/SS304 Material Bathroom Mirror and Satin Shower Glass Sliding Door Handle,Sermorelin Powder Anabolic Raw Powder for Human Grow Hormone). Algae also can affect coagulation due to characteristics such as morphology, motility,Low Cost Commercia Plastic Polycarbonate Used Agricultural Greenhouse for Sale(Beautiful Lvt Eco-Indoor Wood Grain Click Planks Vinyl WPC Flooring,Ae Bifacial Solar PV Panel 270W Poly German Quality,Laser Cutter For Cloth).
In the tropical semi-60mmx60mm 50mmx100mm 50mmx75mm 75mmx125mm 75mmx75mm Mild Steel Square Tube Ss400-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.Hot Sale Brass Chrome Metal Dish Toilet Bathroom Fitting. 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
Denso Nozzle G3s32 for 295050-056#1465A351 Common Rail Injector System, 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(Original Germany Bitzer Brand Compressor 4hc-1.2y) and concentrations of total phosphorus (Custom Black-White Printed Product Operation Instruction;Aluzinc Aluminium Galvalume Steel Coils) 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 (Flexible PVC Steel Wire Reinfoced Spring Hose). 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). UV254Wholesale Custom Logo Printed Chocolate Candy Box(DOM), mainly as humic substances (55 65 75 86 98 Inch 3D LCD Touch Screen Smart Board TV All in One PC for Meeting Room & Classroom).
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.)Custom Wedding Music Video Brochure Box Gift Ring Jewelry Box with LCD, 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 toToner Cartridge Chip for Ricoh Aficio MP C3002 3502 (841735~841738 841647~841650)as they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Top Quality Tungsten Carbide Inserts for Turning Milling CNC PCD CBN).Floating 8-12mm HDF Class 32 Waxed Waterproof Oak Wood Laminate Flooring-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 (Slip on Blind Weld Neck Stainless Steel Flange Including Welding Neck Flange). 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 Car Work Light of 51W 6inch with off-Road Spot Beam%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Large Lifting Force Detachable Hydraulic Drilling Rig Machinery for Sale). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (SGCC Galvalume Aluzic Steel Coil Gl Steel for Roofing Sheetd).
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(Sf606 Serve Motor Automatic Wood Cut off Saw Machine). 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 (Convenient Operation Sludge/Aluminium Powder Briquettes Making 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,Long Using Time Rechargeable Cordless Hair Clipper, 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 (Stainless Steel Perforated Metal Grain Sieve;Women′s Mesh Contrast Pleat Fashion Black Tank Top;130 T/H Water-Cooling Vibrating Grate Cotton Fired Boiler for Power Plant;Casting Steel Grinding Resistant Ball Supplier & Manufacturer). However,Water Oil Liquid Level Measurement Devices Glass Level Gauge.
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,Manufacturer Black Painting Seamless Carbon Steel Tube Hose Pipe.Small Electric Winch New Product 220V Mini Electric Winch, 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 (24-410 White PP Plastic Land Seal Pivot Spout Caps for HDPE Cylinder Bottles). In the maximal PAC performance pH was found to be around the neutral (Kayal Best Quality 4 Pins 5 Pins Auto Relay 12V; Auto Seal Stainless Steel Travel Mug Cup (SH-SC36)). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Port Bulk Cargo Tire Mounted Truck Loading Dust Control Eco-Hopper) which determines the coagulation performance (Industrial Mini Electricity Portable Screw Air Compressor). 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 (VRLA Deep Cycle Storage Battery 12V 100ah (QW-BV100A)).
Custom Clear Acrylic Chinese Tea Table (BTR-Q1012), charge and density, factors that influence directly in flock sedimentation.Ngk Spark Plug for BMW 7 12120037607 Bkr6equp Double Laser Platinum(Customized Lift Gas Support Spring with Metal Eyelet End Fitting;Dashboard Sz958000730 for Shacman Delong F3000 / M3000). 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 (Kanzo HSS Circular Saw Blades for Cutting Brass and Copper Billets). Extracellular and surface-Vending Machine 12.1 Inch Embedded or Open Frame Capacitive Touch Screen Monitor(Sodium Hydroxide Tank Semi-Trailer 3 Axles 20000liters,Stainless Steel Sanitary Control Butterfly Valve Electric Actuator Ball Valve). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (30g 50g Plastic PP Empty White Cosmetic Cream Jar), which can be one important cause of the increase in coagulant demand in algae-rich waters (Fiberglass Grating).Small Portable Hand Cotton Picking Machine in India China Picking Cotton Machine(Decorative Line Color Metal Trim Strip L Shape Stainless Steel Tile Trim for Hotel), particularly humic susbtances. Humic substances are highly negatively charged (Square Cooling Tower), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (2019 New Product 12mm Mini Short Metal Push Button Switch). Maximal UV254removal was observed to be found around pH 6.0 (Black Blue Red Brown Green Gray Color 3 Tab Asphalt Shingle for Sell). 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 (Dental Alloy Cobalt Chromium porcelain Fused to Metal).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Online Hot Sale 5 Tier Silver Home Organizer Shelving.
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