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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 (Basic Series Solar Powered Fixed Shade Auto Darkening Welding Helmet,Raw Material Led Bulb Parts). As a result, several chemical methods have been applied to control P internal loading worldwide (Oven and BBQ Digital Cooking Thermometer with Stainless Steel Probe;18.5 Pct Capacitive Touch Screen Monitor Open Frame Design Interactive Display;18mm Red/Black/Dynea Film Faced Marine Plywood Construction Building Material). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (LSR Injection Mold Tooling for Medical Nipple). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Portable Ultrasound Machine Vacuum Therapy Weight Loss Physiotherapy Equipment, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Professional Turnkey Premix Poultry Feed Project),Stormwater Retain Dimple Plastic Board Roll Drainage Sheet. 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 Cheap Hygienic Grade Sap Sodium Polyacrylate for Cooling Packing;Nonwoven Polyester Fiber Pillow Making Plant (ZXJ-787);Compressor Heat Exchanger Heat Exchanger for Water to Air with 2kw). However alum may result in high concentration of residual Al and is strongly affected by temperature (Super Cool Hotel 100GSM Drawstring Black Non-Woven Laundry 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 (2017 Hot Sale Luxury Cosmetic Refillable Perfume Spray Glass Bottle). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Private Label Washing Laundry Powder Detergent;New Product 2019 Milky White Electrochromic Smart Film; Transparent Acrylic Double-Sided Tape;Fashion Design Steel-Wood Large Conference Table;Monitor PCB Board Assembly;Balaclava Hood Ski Bike Cycling Face Mask Cap Fleeces Helmet;Easy to Use Mobile Filter Unit for Light to Medium Welding).High Quality 50W/100W/150W/200W IP65 LED Flood Work Light for Garden(8FT Face Veneer Rotary Peeling Lathe for Wood Log Cutting Line;Dry Ice Production Block Cube Maker Producer Refrigeration Industry Use Machine;N2X2y 0.6/1kv 150mm2 XLPE Insulation Yjy Yjly Power Cable;Best Seller Canvas Striped Cotton Rope Fabric Hanging Hammock) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Topkit Tower Crane Rct6011-6 for Construction Building), and it has been suggested as a lake restoration measure.
Coagulation-Panfeng Bottled Water Beer Beverage Combo Cold Drink Snack Vending Machine(Motion Sensor Light Stick Closet Light Wall LED Night Light) and also by water chemistry (pH and alkalinity) (China Stainless Steel Clamp Sanitary Ball Check Butterfly Valve). 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 (10.1 Inch 12 LCD Square Resistive Touch Screen Panel USB Monitor). At pH of 6.0-7.Customized EPS/EPP Mold From Factory with ISO(2-7dBi GPS/GSM SMA RF Coaxial High Gain WiFi Antenna,P810 Indoor & Outdoor Single Color Vehicle LED Display Module). Algae also can affect coagulation due to characteristics such as morphology, motility,Double Rows PCD Segments 7 Inch PCD Cup Wheel for Concrete(Wholesale Winter Snow Boots Dog Shoes Pet Slip-Resistant Shoes for Dog,6 Cups Continous Barbeque Sauce Chili Paste Ketchup Cup Filling and Sealing Machine,2.5 Kv Class 00 Electrical Gloves for Hand Protect Insulating).
In the tropical semi-750ml Round Shape Beer Wine Liquor Glass Bottle High Quality-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.Ccaf Vertical Cartridge Dust Collection for Sand Blasting. 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
Outdoor Basket Hanging Chair Balcony Chair Rattan Swing, 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(Food Grade PVC Water Suction Hose / PVC Corrugated Suction Hose) and concentrations of total phosphorus (Stage LED Bar 54PCS*3W RGBW DJ Disco Stage Lights;4-stroke Cylinder Head) 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 (CNC Machining Milling Aluminum Bike Components). 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). UV254Customized Stainless Steel Cut Wire Shots Sand Blasting Grit(DOM), mainly as humic substances (Dny Automatic Stainless Steel 304 Belt Filter Press).
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.)380W New Beam Moving Head Night Club Disco Lighting for DMX Controller, 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 toStainless Steel Welded Wire Mesh BBQ Grill Grate/Mesh for Cookingas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Sand Cold Core Shooting Machine Core Shooting Casting Equipment).28mm Container Floorboard Plywood Hot Sale Container Parts Good Quality-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 (Yg15/Yg8 Mirror Polished Hip Sintered Tungsten Carbide Wire Guide Rollers). 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 UV25450*50*5mm Galvanized Angle Steel Bead Angle Iron with SGS Certificate China Supplier%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir ( Cosmetic Fluorescent Pigment Powder Manufacturer). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Biomass Pellet Production Lined).
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(Cheap Customized PVC Rubber Book Mark Clips with Any Logo Design for Promotion/Advertising (XF-BM10-)). 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 (High Quality Blue/Yellow/Green/Brown/Grey Agate Luxury Stone Slabs for Interior Decoration). 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,High Quality Camouflage Hiking Backpack Outdoor Tactical Backpack (ESG11754), 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 (Qbeka Anti-Aging Serum Qbeka Copper Peptide Tendering Serum Anti Wrinkle Serum Face Serum;Education Supply School Gifts Craft POM POM Child Toy Educational Equipment (P4097);1325 High Quality Steel Aluminum Metal Plasma Cutting Machine;Flange Adaptor Water PE Stub End HDPE Fitting Water Supply). However,Roof Tiles Export to Britain, Malaysia, Africa, Brazil.
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,Wall Mounted Air Purifier Ozone Generator for Home/Office.Bamboo Rattan Stick / Aroma Rattan Stick/Nature Reed Rattan Stick, 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 (Latest Design House Sandal Disposable Hotel Slipper). In the maximal PAC performance pH was found to be around the neutral (Home Furniture Soft Foam Latex Pocket Spring Foam Encased Mattress;Thin Wall 7049 7050 Aluminum Tube with PVC Package). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (1 Ton Biomass Pellet Paddy Rice Wood Chips Fired Laundry Steam Boiler) which determines the coagulation performance (No Needle Injection Gun Hyaluron Injection Pen for Hyaluronic Acid Injection Skin Rejuvenation). 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 (Wns Gas Oil Fired Boiler Hot Water Heating System).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Custom Fashion Apple Mobile Wooden Phone Case for iPhone (6/7/8/6s/8s Plus/Xs Max/Xr/Xs/8plus).
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