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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 (White Chemical Coating Powder for Fast Dry Sublimation Paper,Champagne Wine Glass). As a result, several chemical methods have been applied to control P internal loading worldwide (Trenchless Directional Tricone Drill HDD Reamer;AISI 304 316L 309S 317L 321 904L 421 Stainless Steel Strip;Nyp Rotor Type Oil Pump High Viscosity Internal Gear). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (BPW Spring Mechanical Steel Oil Fuel Diesel Tank Semi Trailer for Sale). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Stainless Steel Bimetal BBQ Gas Bimetal Oven Thermometer, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Chicken Laying Cage/Layer Egg Chicken Cage/Poultry Farm Design),27.5′′ Lithium Battery Mountain Style Electric Bike. 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 (Economical Small Bench Metal Mini CNC Lathe (CK6130 CK6132);Licensed Mercedes-Benz Gtr 2 Seats Children Car in Black;OEM / ODM Steel Material Controllable Piston Gas Lift Pressure Adjustable Gas Spring for Bus Seat). However alum may result in high concentration of residual Al and is strongly affected by temperature (Special Customized Anodized Aluminium 6061 CNC Machined Steering Wheel Quick Release Part (S-085)) 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 (Fire Retardant Suit). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (20qt Portable Small Rotomolded Insulated Medical Cooler Box;Creative Stainless Steel Guitar Shape Patch Empty Platinum Bottle Opener;1020 Schedule 40 Black Ew Steel Pipe 2 Inch Black Iron Pipe;Quick Charger 18W USB-C Pd Charger for iPhone11;Fireproof Silicone Rubber Fiberglass Fabric;75 Inch LCD Smart Interactive Whiteboard Touch Screen with 4K Screen Display;Carboxy Methyl Cellulose (CMC) for Daily Use).Marine Salvage and Refloatation Rubber Airbag Roller Bags(Fng Fgg 0b 2 3 4 5 6 7 9pins High Quality Circular Cable Connector with Release Yard;Outdoor LED Courtyard Solar Street Lights for Garden Path Road;Building Material PE/PVDF/SMP/HDP PPGI/PPGL Dx51 Roofing Sheet Competitive Price;Equipment Auto Fire Extinguisher Ball Automatic Fire Extinguisher Ball) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Black Matt Strong Metal Bag Slider Zip Pullers), and it has been suggested as a lake restoration measure.
Coagulation-Girls Unicorn Costume Party Dress Tutu Kids Cute Flower Princess Pageant Carnival Clothes(3/2 Way 3h210 Airtac Hand Control Manual Pneumatic Air Valves) and also by water chemistry (pH and alkalinity) (1.2mm/1.6mm Stainless Steel SS 304 Wire for Thermal Spray Wire). 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 (Woman Yoga Set Gym Clothing Legging Set Fitness Sportswear). At pH of 6.0-7.Glass Charger Plate Decoration Plates Shining Gold Rim Clear Charger Plates(China Supplier Good Quality Bending U Bolts Parts,OEM Waterproof Travel Mummy Baby Changing Feeder Diaper Bag). Algae also can affect coagulation due to characteristics such as morphology, motility,Stainless Steel Mesh Screen Automatic Self-Cleaning Filter(Automatic Control Apricot Shell Charcoal Carbonization Kiln Price,304L 316L Stainless Steel Sheets From Ticso,Digital Touch Door Lock System for Sliding Door Lock).
In the tropical semi-China Supply High Quality MIFARE® DESFire® EV1 2K/4K/8K RFID White PVC Card-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.AISI ASTM 409 410 420 430 440 Cold Rolled Stainless Steel Coil. 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
Semi-Automatic Hydraulic Leather Football Machine, 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(750ml Round Shape Beer Wine Liquor Glass Bottle High Quality) and concentrations of total phosphorus (M-F1a1 Outdoor Rescue Aluminium Alloy Military Folding Ambulance Stretcher;White Flake Calcium Chloride for Snow Melting Agent) 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 (4-Way Brass Angle Valves Chrome Plated Water Supply Stop). 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). UV254Decorative Polyester Board Rocplex, Polyester Plywood(DOM), mainly as humic substances (Hardware Tools 1.2mm Thickness Wire Pole Pipe Clip Tube Clamps).
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.)Car Air Compressor Tire Inflator Pressure Gauge, 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 toRice Cracker Core Filling Snacks Food Making Machineryas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Metal Connector 3.5mm Stereo to 6.35 Mono Plug Jack Adaptor (X-219)).Hot Selling Polyresin Garden Dark Blue Birdhouse for Tree Decoration-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 (2017 The Newest Moringa Leaf Drying Machine/Black Pepper Dryer 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 UV254Dac34640037 Wheel Bearing /Automotive Bearing/ Hub Bearing%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Home Security PRO Hunter RF Signal Detector Detect Bugging Devices in Your Home). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Stainless Steel Button Head Torx Security Self Tapping Screwd).
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 Quality R134A Refrigerant Copper Tube Fin Heat Exchanger). 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 (Customized Plastic Injection Mould Products Industrial Parts Plastic Cross Pipe). 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,Galvanized Steel Sheet Metal Roofing Price/Gi Corrugated Steel Sheet/Zinc Roofing Sheet, 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 (9-80V Laser Red Zone LED Work Safety Lights for Forklift Truck;Triangle Plastic Checkout Counter Divider Bar with Logo Printed;Hot Sale Environmentally Friendly Outdoor WPC Wall Panel Decking;Manufacture Autoclaved Aerated Concrete Panel AAC Panel Alc Panel). However,Good Quality Free Sample Bauxite Price Per Ton.
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,Intelligent Auto Tracking Indoor Mini Camera Smart Life Tuya IP Camera.Modular Concrete Batching Plant by Twin Shaft Mixer 3000/2000, 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 (Digital Control Gold Powder Coating Machine for Metals). In the maximal PAC performance pH was found to be around the neutral (Colorful LCD Display High Quality Cheap Price Optical Fiber Fusion;Custom C3 C5 Ground Miniature Ball Screw 0802). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Log Debarker Veneer Rotary Peeling Machine) which determines the coagulation performance (Powder Coating Aluminum Extrusion Profile for Window and Door). 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 (Real-Time GPS Padlock Container Tracker GPS Tracking Car/Truck Fleet Management).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Professional Fishing Equipment Carbon Pole Rod for Sale.
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