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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 (Silver Reflective One Way Vision Film as Mirror Performance (SF101),Double Acting Super High Pressure Hydraulic Presses Cylinder and Cylinder Parts). As a result, several chemical methods have been applied to control P internal loading worldwide (13.56MHz Logo Printing Mini NFC Epoxy Card for Access System;PPGI/PPGL Prepainting Galvanized Steel with Ral Color;Book Matched Marble Tiles Wall Design in Hotel Hall Natural Blue Macubas Marble Slab). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Highway Outdoor Road Integrated Solar LED Street Light Price List). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,Large Music Controlled Colorful Laser Water Fountain, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Sanitary Adjustable Air Release Breath Pressure Relief Valve),Waterproof 576*576mm Outdoor Full Color P6 LED Display Advertising. 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 (Glacial Acetic Acid Tech Grade and Food Grade Glacial Acetic Acid;Light Weight Concrete AAC Brick/Block Making Machine for Wall Material;Commercial Automatic Ultrafine Air Jet Mill for Sale). However alum may result in high concentration of residual Al and is strongly affected by temperature (Thickness 140 Micron Pharmaceutical Cold Forming Blister Aluminum Foil) 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 (Welded Steel Pipe). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (Wiskind Fireproof Hydrophobic Waterproof Rock Wool/Glass Wool Sandwich Panel;Sewage Pipeline Detection Robot with Strong Driving Force;Multi-Function Solar Power Generation System for Remote Areas;Sj Good Price Plastic PE Pipe Making Extrusion Extruder Machine;HRC50-55 Tungsten Steel Carbide Square End Mill and Carbide Ball End Mill;Weight Loss Equipment with Cryolipolsis Fat Freezing 40K Cavitation Rflipo Laser;Baili Colorful Lights 500ml Aroma Scent Fragrance Diffuser).Foil Induction Sealing Machine for Glass Plastic Bottle Jar(Fully Thread Square Neck Carriage Bolts DIN603 M6X35mm 304 Stainless Steel;2 Pin Waterproof Soldering Socket Waterproof Extension Cord Connectors;High Quality Stainless Steel Architectural Ring Mesh;Auto Defrost Island Supermarket Freezer for Frozen Foods Display (RG-20)) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Kunlun Paraffin Waxes From Petroleum Made in China), and it has been suggested as a lake restoration measure.
Coagulation-Non-Mainstream Leather Retro Bracelet/ All-Match Fashionable Leather Bracelet(Ce Certificate Factory Provide Drink Water Vending Machine) and also by water chemistry (pH and alkalinity) (Down Film Rolling Bag Wrapping Big Bread Packing Machinery 450X). 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 (Mobile Phone Accessories for iPad Leather Case). At pH of 6.0-7.Good Injection Molding Service, Plastic Molding, Injection Moulding Manufacturer(CNC Machine Linear Guide Accordion Bellows Cover,Metal Wire Mesh Knitting Scourer Machine with 220V 380V Voltage). Algae also can affect coagulation due to characteristics such as morphology, motility,China Factory Hollow Pneumatic Piston Rod(Brown Shoes High Quality Strong Protection Working Shoes,100% Pure PC Suitcase Luggage Aluminum Trolley Bags for Travel,CL1C-I100G Comlom Stainless Steel Vacuum Travel Coffee Pot With Strap).
In the tropical semi-CNC Machining Duct Forging Stainless Steel Flange-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.Chemical Carbon Plastic Frames V Bank Filter Activated Carbon. 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
10/30/50ml Single Gourd Shape Amber Essential Oil Cosmetic Glass Dropper Bottle for Mushroom, 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(Bubble Cloth Seersucker Honeycomb Style Polyamide Knit Bikini Fabric) and concentrations of total phosphorus (Plastic Tpd E Juice Bottle 10ml with Colorful Cap;Digital Laser Cutting Safe) 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 (Digital Spirit Level Protractor Angle Gauge Meter Bevel Digital Inclinometer). 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). UV254Alibaba Clear Aluminum Corrugated PVC Roofing Sheet /Corrugated Roofing Sheet India(DOM), mainly as humic substances (IEC Standard FC APC PLC Splitter for Gpon Equipment).
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.)Fresh Mung Bean Filling Stand-up Pouch Packing Machine, 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 toCabinet Base Work Table with Drawers and Sliding Doorsas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Best Selling Manufacture Green House with Hydroponic Growing Systems on Sale).Custom Bracelet USB PVC Segmented Tag Wristbands No Minimum Order-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 (10inch Tire Two Wheel Self Balance Electric Scooter). 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 UV254Newest Robot Vacuum Cleaner with GPS, Camera, Built-in Virtual Wall%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Hot Dipped Galvalume Steel/Aluzinc Steel with Anty-Finger). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (m.hkymould.netd).
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(Promotion Stock Silicone Tea Infuser for Kitchenware). 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 (1.2344/AISI H13/8407 Stainleess Steeel for Thread Rolling Die). 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,Flat Screen 15 17 19 24 32 Inch Smart HD Color LCD LED TV, 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 (Outdoor Food Meal Heating Bag for Travelling and Camping;Artificial Push up Breathable and Strapless Adjustable Invisible Silicone Bra;Top Quality Vehicle GPS Tracker with Fuel Cap Sensor M508;Metal Strap for Xiaomi Mi Band 4 Milanese Watch Band). However,1616 Aluminum LED Strip Channel Surface Mount LED Extrusion.
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,600d Polyester Trolley Luggage Soft Luggage Oxford Luggage Bag.Export Quality Flavor Fresh Ramen Mixed Noodle with Turkey Sauce, 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 (430 Black Mirror Decorative Stainless Steel Sheet in Foshan). In the maximal PAC performance pH was found to be around the neutral ( Door;Square Shape Glass Perfume Bottle Refillable Glass Perfume Bottle Atomizer Mist Bottle). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Atex Approved Level Measuring Instrument Level Sensor) which determines the coagulation performance (Brewery Wholesaler Quotes & PriceList). 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 ( LPG Hose Best Choice for Home Use).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Single Head High Speed Tubular Cap Embroidery Machine (TLC901).
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