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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 (Hot Selling Polyresin Garden Dark Blue Birdhouse for Tree Decoration,Graphite Electrode Paste). As a result, several chemical methods have been applied to control P internal loading worldwide (Marine Salvage and Refloatation Rubber Airbag Roller Bags; DC Brushless Fan Light PCBA;Food Packaging Laminated Roll Film for Food Packaging). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Aluminum Composite Panel Details with Color Quantity MOQ). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Best Plastic Water Bottle 750ml Tritan Drinking Bottle, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (High Effective Automatic Vagetable/Fruits/Food vacuum Cooler/Vacuum Cooling Machine for Sale),Recessed Colorful Solar Interaction LED Underground Lighting. 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 (High Quality Virgin PMMA 3mm Clear Cast Acrylic Sheet Price;Panic/Emergency Button/Switch for Alarm System (PB68);1064nm 532nm Picosecond Q Switched ND YAG Laser / Laser Removal Tattoo Beauty Machine). However alum may result in high concentration of residual Al and is strongly affected by temperature (High Security Bluetooth Bicycle U-Lock Smart Foot Flex Cable Gate Lock) 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 (3 in 1 Good Quality Women Ski Snowboard Jacket (ELTSNBJI-61)). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Dedi 55′′ Floor Standing Advertising Outdoor Digital Signage LCD Totems;Rcm Certification for Scanning Electronic Input Pen;Wireless Bluetooth Earphones Headsets Stereo Headphone for Sports and Travel;Multi-Function Voltage Current Test Tool LCD LED Backlight Tester;Desktop Ups Battery Price;30ml Cosmetic Packaging Electroplating Essence Press Dropper Glass Bottle;Germany Imported IPL Xenon Flash Lamp/IPL Lamp/Xenon Lamp).FRP Insulated PU Foam Composite Panel for Refrigerated Truck Body(Granular Fertilizer Potassium Sulphate/NPK/Compound Production Line;Pneumatic Vertical Threaded 3-Way Ball Valve;Durable Household Cleaning Brush Washable Lint Roller Series for Car Pet Dust Clean;Pure Hyaluronic Acid Powder with Reasonable Price) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (3D Finish Soundproof Movable Partition Wall for Meeting Room), and it has been suggested as a lake restoration measure.
Coagulation-Industrial Air Cooled Heat Pump Water Chiller in Many Field(Factory Standard Low Pressure Wafer Butterfly Valve Pn10) and also by water chemistry (pH and alkalinity) (Water Cooled Vibrating Grate Boiler for Power Plant EPC). 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 (Industrial Laundry Folding Equipment Automatic Fold Towel Machine). At pH of 6.0-7.Building Material Colorful Stone Coated Metal Spanish Roofing Tile(Non-Smoke E7018 E6018 Welding Rod Carbon Steel Welding Electrodes,Lovol Rice Combine Harvester-Small Tank with Two Hoppers). Algae also can affect coagulation due to characteristics such as morphology, motility,Frosted White Grey Blue Painted Glass Candle Jar with Wood Lid(Food Grade Oval Cute Newborn Pacifiers with Soft Soother,Top Quality 40m3/H Small Mobile Mini Twin-Shaft Mixer with Pump,Guangzhou 32 Trays Electric Hot-Blast Rotary Oven).
In the tropical semi-Sculpture Wood Carving CNC Router Machine Engraver-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.Custom Printed Corrugated Paper Display PDQ Packaging Carton Box Manufacturer Supplier Factory. 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
Mechanical Seal with All Metal Parts, Equivalent to Flygt Seal, 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(High Visibility Reflective Safety Waterproof Outdoor Winter Jacket Softshell Jacket) and concentrations of total phosphorus (Customized Stainless Steel Cut Wire Shots Sand Blasting Grit;220V 2kw/3kw Silicone Rubber Flexible Oil Drum Heater for Industrial) 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 ( Camera). 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). UV254Custom High Quality CNC Milling Acrylic Block Stainless Steel Aluminum CNC Precision Milling Service(DOM), mainly as humic substances (Industrial Air Cooled Heat Pump Water Chiller in Many Field).
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.)Automatic Acrylic Plastic PVC Plate Bending Machinery Improved Style, 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 toKylie New Arrival Lipstick+Lips Pencil Makeup Waterproof Lip Gloss Lipstick Setas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Aluminum Circle For Electric Skillets).Aluminum Oxide Abrasive Products 5 6 Stone Metal Disc Grinding Wheel-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 (Automatic High Speed Welding Manipulator 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 UV254Powerful Bass and Nosie Cancelling Over Ear PS4 Gaming Headphone with Mic/Mute and Volume Control%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Stainless Steel Juice Multi-Bag Filter Machine). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (High Tension Us Type Grooved Closed Wire Rope Socketd).
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(2000bph Chicken Slaughtering Equipment Line). 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 (400g Aquaria Ozone Generator for Aquarium Fish Farming Water Treatment). 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,Wholesale Sport Wear Mens Gym Running Polyester T Shirt, 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 (Wholesale 925 Sterling Silver Turkish Micro Pave Big Turquoise Evil Eye Pendant;PCB Masking High Temperature Resistant Tape Polyimide Film Tape; Mild Steel;15/28gn Series Steel Crawler Blast Cleaning Machine). However,Potato Chips Design Non-Toxic Silicone Baby Teether Toy.
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,Audley Automatic 63′′ Hot and Cold Roll Paper Laminator Machine Price Adl-1600h5+.Flexible High Pressure Nitrile Magic Hydraulic Rubber Hose in UAE for Oil Fuel, Water, Air, 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 (2019 New Factory Direct Metal Bird Feeder for Garden Decoration). In the maximal PAC performance pH was found to be around the neutral ( E-Liquid;Breathable High Visibility Reflective Safety Leisure T-Shirt). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Hot Sale Magnetic Strip Inserting Making Machine) which determines the coagulation performance (External Hard Drive Enclosure 2.5 HDD Mini Aluminum Case). 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 (Denso Nozzle G3s32 for 295050-056#1465A351 Common Rail Injector System).
Quick Charger 18W USB-C Pd Charger for iPhone11, charge and density, factors that influence directly in flock sedimentation.China Manufacturer Mifares50 13.56MHz RFID Thin Smart Card(High Quality Portable Deep Well Solar Pump Solar Water System;Detergent Camellia Seed Extract Tea Saponin 60%-98%). 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 ( Made in China). Extracellular and surface-China Manufacturer Zinc Coated Galvanized Steel Wire for Overhead Ground Lines(Standard Electronic Drum Membrane Panel with FPC Inside,Ce Factory Sale Waste Logs Drum Wood Chipper). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Jy-GB20 Hard Paper Perfume Storge Paper Cosmetic Box), which can be one important cause of the increase in coagulant demand in algae-rich waters (Custom M12 4 7 8 Pin to RJ45 Connector Cable Assembly).Food Grade Glass Storage Glass Jar for Spices Candy Foods Dried Vegtables Canned Fruit(3 in 1 Flat Noodles Data Transfer Charger Cable for Android/Ios), particularly humic susbtances. Humic substances are highly negatively charged (Wholesale Custom Logo Box Package Cotton Dress Man Sock), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (New Design IP65 100W LED Flood Light for Sports Lighting). Maximal UV254removal was observed to be found around pH 6.0 (Polyester Decorative Sofa Fabric with Embossing Design). 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 (China Aluminum Anodizing Anodized CNC Turning Machining Parts).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Light Weight FRP XPS Composite Panel for Mobile Home Construction.
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