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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 (CNC Fiber Laser Cutting Machine with Pipes Cutting Accessories,Perfume Bottle Glass 50ml). As a result, several chemical methods have been applied to control P internal loading worldwide (Pressure Swing Adsorption Medical Oxygen Concentrator Psa Medical Equipment;Sheet Metal Stamping Galvanized Steel Panel and Frame;Automatic Vertical Grain / Sugar / Bean / Rice Packing Machine). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (IP65 8W Outdoor Integrated LED Street Light Solar Lamps). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Metalized Pink Color 3ml 5ml 10ml Perfume Roll on Container Bottle with Gold Aluminum Cap, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Compostable Film Blowing Extrusion Machine),Popular Lifejacket EPE Foam Life Vest for Water Safety Equipment. 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 (CNC Turning Stainless Steel Part with Precision Tolerance;Stainless Steel Rectangular Pipes for Balcony Guardrail;Modified Shipping Container House for New Zealand). However alum may result in high concentration of residual Al and is strongly affected by temperature (Cast Iron Casserole Pot Roaster with Cover 7L Oval Dutch Oven) 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 (Famous Exported Construction Machinery Wall Plastering Machine). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (THK Linear Guide Shs Hsr SSR 15 20 25 30 35 45mm for CNC;Socket Type 2 32A 22kw EV Charging Point EV Charger for Electric Vehicle Charging;Gas Spring for Cabinet Gas Struts for Kitchen Cabinet Door;2019 New Crop Blanched Peanut Kernels (long shape) From China;380v Frequency Inverter;Absorbent PP Mat Hardwearing Doormat with Round Shape;China Wholesale Hydraulic Industrial Winch for Mining Well).OEM Aluminum Housing Fuel Filter Housing for Truck/Train Parts(LPG Gasification Pressure Regulating Skid in Mobile Station Building;3L 5L 7lstainless Steel Vertical Manual Meat Stuffer Sausage Filler;Mdf Wood Price;Aluminium/Brass/Stainless Steel Cam Lock Quick Coupling) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Fashionable New Products Twin Screw Extruder for Pet Recycling), and it has been suggested as a lake restoration measure.
Coagulation-Rare Earth Metal Material Cerium Target for Magnetron Sputtering System(5/8 Inch Stainless Steel Banding in Plastic Tote) and also by water chemistry (pH and alkalinity) (Electric Rail Transport Wagon Warehouse Transfer Vehicle). 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 (3 Pole Contactor). At pH of 6.0-7.Hot Sale High Grade Popular Jacquard Curtain Fabric for Living Room/Bedroom(Ductile Iron Ggg50 Pn16 Quick Automatic Air Pressure Release Valve,Ceramic Tile Plasma Ion Deposition Planting Functional PVD Vacuum Coating Machine). Algae also can affect coagulation due to characteristics such as morphology, motility,Custom Diecasting Fashion Zinc Alloy Enamel Metal Name Tag(Low MOQ Perfect Binding Soft Cover Book Printing High Quality,24V/48V 40A/80A MPPT Solar Charge Controller for Solar Power System,Pe Stretch Warp Film).
In the tropical semi-Semi-Automatic LCD IC PCB Cof Soldering Machine-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.Socket Weld Stainless Steel Flange Ss 150#, Pipe Flanges Schedule 40. 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
Household Home Textile Cleaning Cloth Warp Knitted Absorbency Cheap Kitchen Wash Clean, 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(Amino Acid Magnesium Chelate for Organic Fertilizer) and concentrations of total phosphorus (Nc Hydraulic Bending Tube Metal Pipe Bending Processing;Asphalt Shingles Uk) 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 (Naixer Ice Cube/Bullet/Tube/Block Ice Maker/Ice Making Machine for Sale with Ce). 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). UV254Plastic Reflective Raised Pavement Marker Road Stud(DOM), mainly as humic substances (Outdoor Waterproof IP68 LED Structure 3D Arch Street Christmas Decoration Ball Motif Lights).
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.)Most Infinix Like Mobile Phones 6.26′′ HD+19: 0, IPS 720*1520 Display Android 9.0, 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 toPromotion LCM Custom LCD Display Stn FSTN Cog LCD Positive Graphic LCD Display Module foras they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(35 - Wireless Modem Router).Wiiboox One Mini Wholesale Rapid Prototyping DIY Printing Machine Mini Desktop 3D Printer-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 (72tpd RO Water Treatment Sea Water Desalination Equipment). 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 UV254Girl Bedroom Mermaid Design Cute Sweet Silk Cotton Printing Duvet Cover Comforter Cover Quilt Cover%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (New Design Pet Product). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (10 Zone Reflow Ovend).
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(Alibaba Clear Aluminum Corrugated PVC Roofing Sheet /Corrugated Roofing Sheet India). 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 (Mrl Nice Quality Passenger Elevator Observation Home Lift for Sale). 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,Yz25c China Ophthalmic Equipment Wireless Binocular Indirect Ophthalmoscope, 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 ( Wall Rack;Gelatin Empty Gelatin Printed Empty Gel Caps Size 2;Bodybuilding Supplements Polypeptide Hormones Injectable Peptides Ipamorelin CAS: 170851-70-4;heparin cap). However,Waterproof Travel Portable Makeup Bag Wash Gargle Bag.
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,Car Repair Equipment Underground Garage Lift with Double Scissor Lifts.Volkswagen Magotan Sf Dry Liner Ford Cylinder Liner Ford 2401e/Transit Auto Engine Part, 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 (Fashion Jewelry Stainless Steel Rose Gold Gemstone CZ Ring SSR1948). In the maximal PAC performance pH was found to be around the neutral (LED Light Source Stereo Microscope for LED Trinocular Microscope; Aluminum Enclosure for LED). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Luau Pinhole Glasses Promotional Sunglasses Yiwu Market (B3030)) which determines the coagulation performance (300mm Cable Tray Factory OEM/ODM Products). 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 (Mini Horizontal Axis 100W Wind Generator Turbine).
High Temperature Multi-Jet Ultrasonic Heat Measure Meter, charge and density, factors that influence directly in flock sedimentation.Equivalent to Sew-Eurodrive R Series Inline Helical Gearbox (R38~R168)(Flake /Pellet/ Bead /Powder High Quality Road Snow Melting Agent Magnesium Chloride Exported to Japan 46%;34mm 7 Grade Atlas Copco Marble Gauge Rock Drill Parts Tapered Button Bit). 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 (Scafold Replacer High Efficiency Spider Lift Articulating Boom). Extracellular and surface-Hypoallergenic Polyester Duvet Insert for Hotel Bedding (DPF17060(Compact Loader Prices For Sale, Steel Pipe). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Mild Price A36 1.0425 ASTM A214 Seamless Carbon Steel Tube), which can be one important cause of the increase in coagulant demand in algae-rich waters (Waterjet 87K Intensifier Part Check Valve Body 020077-1).20L Semi Automatic China Bottle Pet Blower(High Speed Double Jersey Computerized Transfer Rib Circular Knitting Machine 2/3 Ways Djjtr), particularly humic susbtances. Humic substances are highly negatively charged (Manufacturer Supplier PU Artificial Furniture Leather for Shoe Materials Lining), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles ( Custom Fire Burner Rings). Maximal UV254removal was observed to be found around pH 6.0 (High Reputation Manufacturing Plant Precast Concrete Steel Pole Mold Sale). 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 (New Design Neoprene Beer Can Cooler).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Apple Shape Kneading Shiatsu Massage Pillow with Heating.
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