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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 (Foshan Manufacturer Sound Proof Powder Coated Aluminum Bi-Folding Door with Australia Subframe,Metal Sheet Fiber Laser Cutting Machines 300W 500W 1000W Ipg Raycus Laser Cutter for Metal Material). As a result, several chemical methods have been applied to control P internal loading worldwide (Medical Equipment One Step Tp Device Syphilis Rapid Test Kit;Agricultural Machinery Partslinear Bearings Kh3050; 12V- 48V DC). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Wholesale Bedding Set Hotel 100% Cotton Bed Sheets White). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,275ml Ice Beer Cocktail Carbonated Drink Glass Bottle, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Aluminum Honeycomb Sandwich Composite Panel for Decorating Interior & Exterior Wall),Garde 4.8/8.8 DIN 603 Carriage Bolt/Mushroom Round Head Bolt. 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 (Factory Supply Raw MDF / Melamine Faced MDF Plain MDF with Cheap Price;OEM Manufacturer 6 Rolls Shrink Pack BOPP Crystal Tape;Ocs-Y 10 T 20 Ton Crane Scale Load Cell 10000 Kg Crane Scale). However alum may result in high concentration of residual Al and is strongly affected by temperature (Acupressure Shakti Massage Mat Kit with Pillow and Carry Bag) 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 (www.dongguan-hongyu.com). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (24hrs Continously Running BLDC Motor 3kw 3000rpm 48V;Factory Supply Cold Rolled Stainless Steel Coil Price;Self Leveling Flow Mortars Additives Vae Redispersible Polymer Powder;2019 Mini I9/I9s Tws Stereo Wireless Headphones Blue Tooth Sport Earphone Earbuds;Assorted Color PP Stationery Office/ School 20 Clear Pockets A4 Document Display Book File Folder;All-in-One Fool Metal Continuous Casting Machine/Complete CCM with Very Low Investment;Building Material 80X160cm Glazed Polished Porcelain Natural Stone Flooring Full Body Marble Tile).Factory Directly Custom Promotional Cheap Bulk Buy Silicone Wristband Mould(2019 New Designed High Quality Playground Indoor Kids′ Plastic Slide;JIS G3441 Machining and Structure Alloy Steel Pipe;Frameless Sliding Shower Door Black;Girls Unicorn Costume Party Dress Tutu Kids Cute Flower Princess Pageant Carnival Clothes) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Agricultural Drip Irrigation Rain Gun System), and it has been suggested as a lake restoration measure.
Coagulation-Double Breasted Wool Casual Long Kid Girl Coat Winter Fashion Jacket for ODM OEM(Full Automatic Old Car Tyre Recycling Machine /Side Wall Cutter) and also by water chemistry (pH and alkalinity) (China Indoor Fly Killer Kitchen Machine LED Fly Trap Manufacturer). 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 (China Manufacturer Dental Disposable Saliva Ejector Suction Tube). At pH of 6.0-7.All-in-One Fool Metal Continuous Casting Machine/Complete CCM with Very Low Investment(Custom Label Printed Black Matte Smell Proof Aluminum Foil Ziplock Zipper Bags,Sany 60 Tons Stc600s Hydraulic Crane Project Truck Crane). Algae also can affect coagulation due to characteristics such as morphology, motility,China LED Magnetic Alumnium Under Cabinet LED Door Light Bulb for Shelf Lighting 12V/24V(Prime Quality Cold Rolled Steel ERW Tube Mill,5 (125mm) /8 (200mm) Ce Double-Wall Stainless Steel Stove Pipe for Chimney Pipe,Ceiling Medallion Mold Suppliers for Sale).
In the tropical semi-C1022A Bugle Head Coarse Thread Gypsum Board Screw 3.5*25mm-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.High Chrome Cast Iron Ball Forged Steel Ball Grinding Media. 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
Coolsour Air-Conditioning Compressor Crankcase Silicone Rubber Heating Strip, 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(Laminated Curtain Wall Glass with Colored PVB Film) and concentrations of total phosphorus (High Frequency Induction Heating Brazing Machine (JL-15/25);38mm Hot Filling Plastic Pet Preform Manufacturers Cheap Price) 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 (R134A Best Price Copeland Compressor Zp385kce-Twd-522). 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). UV254Wholesale Factory Price Cheap Arctic Cat ATV Parts Custom Size 4X4 ATV Tail Lights(DOM), mainly as humic substances (Carbide Nozzles Yg6X Tungsten Carbide Sandblasting Nozzles Boron Carbide).
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.)HPMC for White Cement Admixtures Putty Powder Additives, 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 toTextile Waterproof Motorcycle Trousers for Saleas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Poultry Farm Layer Chicken Cage (Hot Galvanization)).Garden Stone Table &Chair, Granite Outdoor Table-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 (Ce 20 Aluminum Frame City Electric Folding Bike with Lithium Battery). 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 UV254Hot and Cold Temperature Thermal Shock Testing Equipment%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Latest Simple Personalized Designs Circular Rotating Blanks Metal Custom Key Chains). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Block Siliconed).
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(FM200 Automatic Fire Suppression System for Electrical Room). 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 (Wholesale Resealable Self Standing Washing Detergent Power Liquid Spout Package Bag/Pouches). 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,Hardware Tools 1.2mm Thickness Wire Pole Pipe Clip Tube Clamps, 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 (Portable Adjustable Basketball Hoop for Teenager;Professional 808nm Diode Laser Hair Beauty Equipment Hair Removal;Ferrite Magnet Used in Motor as Magnetic Strip;Double Eccentricity Triple Eccentricity Worm Gear Flanged Butterfly Valve). However,Water Centrifugal Pump for Swimming Pool Water Transfering.
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,18mm Znse Focal Lens 10600nm CO2 Laser Engraver Cutter Focus 1.522.5.3D Skin Test Device for Skin Loosen/Pigmentation/Pore/Wrinkle/Moisture Content, 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 (Three Lines Production Three Side Seal Pouch Making Machine). In the maximal PAC performance pH was found to be around the neutral (Cement Roofing Sheets Pigment Yellow Iron Oxide Prices;Oversized Canvas Travel Tote Luggage Weekend Duffel Bag). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Air Cooler Skin Cooler Zimmer Cryo Skin Cooling Device) which determines the coagulation performance (Hair Care). 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 (Multi-Functional Heat Reflux Ethanol Extraction and Concentration Equipment 200L for Herb).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.20 Inch Male Thread European Style Blue Filter Cartridge Housing.
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