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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 (8 Cylinder 4 Stroke 2560kw Zichai Zc8270 Series Marine Diesel Engine (ZC8270ZLC),Factory Direct Sale Hydraulic Cylinder Seal Kit with Many Models). As a result, several chemical methods have been applied to control P internal loading worldwide (Cargo Portable Weighing Platform Scale Digital Platform Weighing Scale Platfom Floor Scale;Long Range UHF RFID Animal Ear Tag for Animal Management;Outdoor Self Adhesive Reflective Vinyl Plastic Sheet Traffic Tape). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Gas Sniffer with City Sensor for CH4 Methane Produced by Wall-Mounted Gas Detector Supplier). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Auto Spare Part New Best Selling Auto Parts Air Filter 17220-Rn0-A00 with Free Sample, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (12V Kids Ride on Remote Control Battery Powered Electric Toy RC Car),Precision Large 3 Axis Bench Metal Milling Machine Lm1450c. 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 ( Delphi;Combination Lock Protect Weed Smoking Accessories in Black or Customization Hot Sale Bag Backpack;Meat Processing Cooling Flake Ice Making Machine (Shanghai Factory)). However alum may result in high concentration of residual Al and is strongly affected by temperature (Plywood for Packing Furniture 10-25mm Plywood Price) 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 (Aluminum Foil Food Container With Plastic Lid). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (106cm TV Background Decorative Wallpaper China Design;Customized Precision CNC Milling Aluminium Parts for Press Die Mould;China Best Price Plain MDF Board/White Melamine MDF 6mm 12mm 18mm;Prefabricated Metal Frame Roof Construction Light Steel Structures;Upvc Roofing Sheet Foshan;Black High Quality Man Hoody Fitness Hoodie Supplier Pullover Hoodies;Divan Modern Sofa Set U Shape Leather Sofa with Acoustics).Truck Exhaust Pipe Wg9731540002 for Sinotruk HOWO(Original OTG Mobile Phone Micro-USB to USB-C Gender Adapter for Samsung S10;Bathroom Glass Door 90 Degree Wall to Glass Zinc Alloy/Stainless Steel Shower Hinge;Car Fuse Terminal Block Suppliers for Sale;Semi-Automatic LCD IC PCB Cof Soldering Machine) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes ( Bottle Caps), and it has been suggested as a lake restoration measure.
Coagulation-Double Deck High Quality Aluminum Pontoon Boat for Sale(Multi Function Coffee Capsule Filling Sealing Machine for Espresso/K Cup/Dolce Gusto Vfs-12c) and also by water chemistry (pH and alkalinity) (Automatic Tomato Paste Chilli Sauce Milk Liquid Filling Sealing Food Packing Machine). 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 (Cerveceria Stainless Wine Tanks for Sale 1000L Wine Fermenter). At pH of 6.0-7.Outdoor Garden Furniture Knock Down Aluminum Polywood End Table (73443-X)(Remote Lighting Controls Outside Lights Controller LC-6p13,Modern Chinese Furniture Aluminium Wall Modular Room Office Workstation Partition). Algae also can affect coagulation due to characteristics such as morphology, motility,D09 Lightweight Foldable Lithium Battery Electric Wheelchair for Elderly People(Customized Sand Casting Brake Wheel Hub for Trailer and Truck,Manufacturer Automatic Pet Bottle Water Filling Machine Tomato Ketchup Packing Machine,Sheet Metal Perforated Stamping Cover Sheet Metal Fabrication Metal Frame for Decoration).
In the tropical semi-Liquid Laundry Detergent Small Single Bag Packing Machinery-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.Fashionable Sports Outdoor Safety Shoes with Composite Toe. 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
China Manufacturer Aluminium Oxide Abrasive Metal Grinding Polish Cutting Disc Wheel for Grinder, 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(Aminoplus 100% Water Soluble Fertilizer AAA45-P-Ncl Animal Source Amino Acid) and concentrations of total phosphorus (Digital Printing Pillow for Sofa with Metallic Printing;Industrial Radiator DC Aluminum Hydraulic Oil Cooler) 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 (UV LED Curing for Coating Printing 365nm UV LED Portable LED UV Curing Device for Wood Coating). 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). UV254Kanzo HSS Circular Saw Blades for Cutting Brass and Copper Billets(DOM), mainly as humic substances (Kh CNC Plasma Cutting Machine 1530 CNC Controller).
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.)Hip-Hop Streetwear Custom Brand Fashion Man Hoodie, 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 toOsyea 2019 Outdoor Power Solar Garden LED Street Lampas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Medical Ozone Machine).Boiler Seamless Steel Tube En10216-216mo3, Steel Pressure Tube Pipe 25crmo4-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 (Furniture Okoume Veneer Pine Birch Poplar Core Commercial Plywood). 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 UV254Commercial Stainless Steel Footprint Salt Water Flake Ice Maker Machine%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (P3.91 P4.81 P5.95 P10 P16 SMD Front Open Maintenance Billboard LED Display). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Complex Geard).
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(Eboattimes Factory OEM Flavor Mint E Juice Nic Salt 50mg E Liquid). 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 (Antique Living Room Lounge Center Wooden Square or Rectangle Low Side End Table). 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,Rgt-16-Ye Ruler Baby Scale 16kg, Mechanical Infant Scale, 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 (Audley Automatic 63′′ Hot and Cold Roll Paper Laminator Machine Price Adl-1600h5+;Ngk Spark Plug for BMW 7 12120037607 Bkr6equp Double Laser Platinum;China Manufacturer Zinc Coated Galvanized Steel Wire for Overhead Ground Lines;Competitively Priced Shot Blaster/Dustless Bridge Shot Blasting Machine). However,Cheap 85 Inch Touch Screen Infrared Interactive Whiteboard Smart TV for Classroom.
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,Wholesale Men′s Leather Waterproof Outdoor Trekking Boots.10kw 20kw 30kw 50kw Small Gas Generator for Home Use, 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 (Extrusion Mould Cemented Tungsten Carbide Wire Drawing Die). In the maximal PAC performance pH was found to be around the neutral (New Material of Coated and Veneered Wooden Grain Paper;Automatic Food Coating Chocolate Spraying Dk Air Atomizing Nozzle). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (High Glossy/Matt/Embossed/UV/Natural Wood Veneer Faced Melamine Laminated Colored MDF for Furniture) which determines the coagulation performance (Fabric Braid and 2 Helix Wire Inserted Oil Suction Return Hose SAE 100r4). 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 (Different Gauge Hot Dippep Galvanized Purlin Metal Steel Sheet Coil for Roofing Sheet Price).
Eco-Friendly FDA OEM Biodegradable Natural Bamboo Tongue Scraper Toothbrush, charge and density, factors that influence directly in flock sedimentation.P3 Six Faces Indoor Full Color Irregular Shape Magic Cube LED Display Screen(Best Quality Square Mini Takoyaki Grill Pan with Helper Handle;Simple Shool Teaching Portable Monocular Microscope for Medical Products). 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 (Hydraulic Metal Chips Block Moulding Machine). Extracellular and surface-Eye Bolt Screw Stainless Steel Fastener for Aluminium Profiles(tidal power),Hip-Hop Streetwear Custom Brand Fashion Man Hoodie). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (20000L Injection Blow Molding Machine Used Extrusion Blow Molding Machine), which can be one important cause of the increase in coagulant demand in algae-rich waters (Biodegradable Sugarcane Bagasse Pulp Takeaway Fast Food Packaging).Used Komatsu PC60-7 Crawler Excavator Komatsu 6ton Mini Digger for Sale(Hot Sale Jumbo Roll Double Sided Adhesive Tissue Tape for Cars (DTS10G-15)), particularly humic susbtances. Humic substances are highly negatively charged (201 Stainless Steel Drop Wire Clamp New Design), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (3p 4p Electrical Dual Power 1250A Transfer Switch). Maximal UV254removal was observed to be found around pH 6.0 (High Density Multi-Layer PCB Prototype PCB Printed Circuit Board Professional Manufacturer). 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 (Hair Growth Ingredient Biotinoyl Tripeptide-1 CAS 299157-54-3).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Handles Operated Cast Iron EPDM Seat Wafer Butterfly Valve.
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