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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 (Crafts Cell Phone Holder Solid Color Polyester/Nylon Phone Strap,m.sltzz.com). As a result, several chemical methods have been applied to control P internal loading worldwide (Customized Full Series Extruded Aluminum Profile for Kitchen; Reusable 3-Compartment Plastic Divided Food Storage; Inflatable Water Game Saturn Rocker). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (47mm Aluminum Paddle Rollers Paint Rollers FRP Tools for Laminating). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Multipurpose Rutile Titanium Dioxide TiO2 Pigment, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Auto Trim Removal Tool Wholesaler Quotes & PriceList),Polynaphthalene Sulfonate Naphthalene Based Superplasticizer Powder. 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 (Bottom Price New Arrival Oxygen Nitrogen Generator Plant;Drx Plastic Injection Mould Making Professional Tech Mold Maker; Chrome 04-7). However alum may result in high concentration of residual Al and is strongly affected by temperature (Breathable Sport Wrist Protector Support Wraps Brace Sleeve) 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 (Exam Gloves). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (43L Big Volume Insulated Backpack Delivery Food/Pizza Bag;Durable Board of Roadway No Parking Sign Board PE Traffic Cone;Oral Real Doll Adult Sex Products Male Masturbator;Dsr350g Top Aquaculture Pneumatic Conveying Pressurization Roots Energy-Saving Blower;m.sunhingstones.com;OEM Service /High Quality Metal Dome /FPC Switch Silicone Push Button with LED;Factory Price Outdoor Wrought Iron Railings Top Quality Delicate Railing Design Metal Fencing).Cemented Carbide Round Rods, Tungsten Hard Alloy Carbide Rods(2205 En1.4462 S32205 2507 En1.4410 S32750 S32760 En1.4501 Duplex Stainless Steel U Channel Bars;P5mm Creative Indoor 3D Effect LED Video DJ Booth LED Screen Display;2 Tier Stainless Steel Rectangle Shower Rack;1.2mm Thick Faux Suede Backing Shoes Leather Fabric) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (60W 6040 Engraving Machine Laser for Paper Cutter Machine), and it has been suggested as a lake restoration measure.
Coagulation-Roll Forged Steel Sheaves for Crane Sheave Block(Inflatable Floating Water Playground Water Island for Commercial Business Usage) and also by water chemistry (pH and alkalinity) (LCD Display Mine Metal Detector for Water Gold Silver Diamond). 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 (Antimicrobial Lamination Film). At pH of 6.0-7.Aluminum Composite Panel Details with Color Quantity MOQ( Steel Pressure Tube Pipe 25crmo4,Abrasives Sandblast /S660 Cast Steel Shot for Shot Peening). Algae also can affect coagulation due to characteristics such as morphology, motility,Wall-Mounted Wooden Commercial Bathroom Cabinet PVC Vanity with Mirror(2019 Bdu Army Camouflage Uniform with 3-Color Desert Color,27.5′′ Lithium Battery Mountain Style Electric Bike,Ammonium Chloride Crystallization Efficient Vacuum Evaporation Crystallization Equipment).
In the tropical semi-China Supplier Iodine Crystals / Iodine Balls CAS 7553-56-2 with High Quality and Good Price-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.Automatic Plastic and Glass Bottle Inductor Sealing Machine. 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
High Speed Double Wall Corrugated Pipe Extruder, Drainage Pipe 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(Filter Press Machine for Sand Washer Sludge Dewatering Working Site in China) and concentrations of total phosphorus (Healong Fashion Sportswear Latest Design Blank Gym Sweatshirts Custom Cotton Hoody Sweatshirts;High Quality Product Hard Drawn Helical Torsion Spring Steel Wire) 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 (Greenpedel X1 Foldable Electric Scooter with Seat for Adults). 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). UV254China Construction Machinery Sheet Metal Parts Manufacturers CNC Auto Parts(DOM), mainly as humic substances (Reinforced Aluminum Foil Pipe Joint Electric Tape Manufacturer in China).
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.)Three Phase Fan Water Pump Electric Asynchronous Induction Motor, 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 toPretty Precisely Automatic PV Strut Roll Formin Machine with High Qualityas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Conical Washers DIN 2093).Star Necklace Jewelry Wholesale Fashion 925 Sterling Silver Necklace Jewelry-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 (220V UFO Shaped LED Bulb E27 Efficiently Energy Saving LED Light). 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 UV254Competitive Wholesale Price Nicotine Salt E Liquid Vgod Mango Bomb%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Mini Building up Block Pen Highlighter Marker Pen Writing Drawing Stationery). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Portable Hard EVA Shell Protective Storage Tool Carrying Cased).
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(Blind Indicators Stud/Strips Stainless Steel Tactile). 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 (Fenugreek Extract Enhance Men′s Sexual Function). 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,Luxury Black Color Shower Door and Shower Enclosure (MB-226), 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 (NF3;Optical Solar Smoke Detector with Testing Button (ES-T601);Wkj-01/Mechanical Thermostat/ Room Thermostat/HVAC Controls;Mgbi Master Alloys Factory & Manufacturer). However,Bottom Price New Arrival Oxygen Nitrogen Generator Plant.
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,1 Ton Biomass Pellet Paddy Rice Wood Chips Fired Laundry Steam Boiler.3mm Poplar Plywood with Fancy Veneer Directly, 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 (1.5 Inch High Pressure Petrol/Gasoline Water Pump). In the maximal PAC performance pH was found to be around the neutral (15kw 19kVA 50Hz Home Standby Weichai Soundproof Diesel Generator;Waterproof Travel Portable Makeup Bag Wash Gargle Bag). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (WiFi Outdoor Security CCTV Battery Solar Powered Wireless IP Camera) which determines the coagulation performance (Desktop 4-Axis Self-Feeding Double Head Double Station Automatic Fastening System). 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 (Tecjet Cloth Printer Printing Machine 6090 DTG Printer).
Copper/Stainless Steel Frying Pan, Cookware Set with Hammer Pattern, Kitchen Utensils, charge and density, factors that influence directly in flock sedimentation.Gondola Supermarket Shelf Candy Shelf for Confectionery Equipment(Home Kitchen Appliance Digital Ozone Generator for Air Water Purifier;Hastelloy C276 Uns N10276 2.4819 Plate Bar Tube Nickel Alloy with China Supplier). 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 (Good Quality Mixing Tank Vacuum Mixing Pot Mixing Reactor Vessel). Extracellular and surface-Plastic Casement Window, PVC Double Glazing Awning Window(Induction Iron Melting Furnace,Automotive Electropainting). Lipopolysaccharide on cell surface ofMicrocystis aeruginosaproduced by the excess of growth exhibited inhibitory effects on PAC coagulation (Aluminium Radiator Core for Profile or Alloy LED Lighting Other), which can be one important cause of the increase in coagulant demand in algae-rich waters (A694 F42 F52 F60 Class 3000 Forged Pipe Fitting Swaged Nipple).Bailian F Customized Server 2019 Hot Sell IPTV Server(Free Sample From Factory High Quality White Kaolin Clay Price), particularly humic susbtances. Humic substances are highly negatively charged (Automatic Block Making Machine Concrete Brick Making Machine Price List), which increases with increasing the pH and by adsorbing onto the surfaces of natural particles (Fein Titanium Bi-Metal Oscillating Saw Blade). Maximal UV254removal was observed to be found around pH 6.0 (PVC Cross Joint Pipe Fittings Equal Pipe Cross). 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 (Customizable High Quality Q38 Series of Catenary Shot Blasting Machine).
In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Portable Adjustable Basketball Hoop for Teenager.
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