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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 (Quick Charger 18W USB-C Pd Charger for iPhone11,26 Lcd Panel Wholesaler Quotes & PriceList). As a result, several chemical methods have been applied to control P internal loading worldwide (75 Inch LCD Smart Interactive Whiteboard Touch Screen with 4K Screen Display;Carboxy Methyl Cellulose (CMC) for Daily Use;Fng Fgg 0b 2 3 4 5 6 7 9pins High Quality Circular Cable Connector with Release Yard). The most used technique is the precipitation and inactivation of phosphorus by coagulants, especially those based on aluminium (Al) (Outdoor LED Courtyard Solar Street Lights for Garden Path Road). When Al salts are added to water, Al+3preferable reacts with PO4-3and forms a precipitate,China Genuine Leather White Color Safety Shoes, flocculation and subsequent sedimentation. Besides this, coagulation and flocculation are also able to remove inorganic and organic suspended particles (Printing Mesh Fabric),High Precision CNC Milling Aluminum Case Electronic Spare Parts Custom Watch Housing. 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 (Equipment Auto Fire Extinguisher Ball Automatic Fire Extinguisher Ball;Black Matt Strong Metal Bag Slider Zip Pullers;3/2 Way 3h210 Airtac Hand Control Manual Pneumatic Air Valves). However alum may result in high concentration of residual Al and is strongly affected by temperature (1.2mm/1.6mm Stainless Steel SS 304 Wire for Thermal Spray Wire) 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 (2019 China Industry Production Automatic Liquid Paint Spraying Booth Use New Technology). A number of laboratory and field experimental studies has shown the superior performance of PAC in both turbidity and phosphorus removal (China Supplier Good Quality Bending U Bolts Parts;OEM Waterproof Travel Mummy Baby Changing Feeder Diaper Bag;Automatic Control Apricot Shell Charcoal Carbonization Kiln Price;304L 316L Stainless Steel Sheets From Ticso;Low Carbon Steel Pipe;Washroom Systems Wc Changing Wet Room Ensuite Shower Room Cubicles Prices;Yellow Nitrile Fully Dipped Gloves Labor Protective Safety Work Glove).Custom-Made Wild Bluebell Cologne Spray Perfume in Crystal Glass Bottle 30ml for Body(750ml Round Shape Beer Wine Liquor Glass Bottle High Quality;M-F1a1 Outdoor Rescue Aluminium Alloy Military Folding Ambulance Stretcher;m.reclining.cn;6 Head Garment Computerized Embroidery Machine Industrial Use for Sale) and turbidity even at low dose (1.5 mg Al.L-1) in shallow lakes (Carnival Rides Samba Balloon Race Happy Swing Jellyfish for Sale), and it has been suggested as a lake restoration measure.
Coagulation-Cosmetic OEM Gold Pet Foam Bottle for Cosmetic Packaging and Face Cleam(4-Way Brass Angle Valves Chrome Plated Water Supply Stop) and also by water chemistry (pH and alkalinity) (Hardware Tools 1.2mm Thickness Wire Pole Pipe Clip Tube Clamps). 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 (Comfortable Durable Cotton Large Pet Car Seat Cover with Pokets). At pH of 6.0-7.Agriculture Cultivator Springs Double Spring Tines 3.5-12mm(Hcd600 RF Wireless Remote Control Duplicator Machine for Locksmith,Wallbox Socket Type 2 16A 3.7kw Single Phase EV Charging Point EV Charger for Electricvehicles). Algae also can affect coagulation due to characteristics such as morphology, motility,Magic Mirror Facial Skin Analyzer / 3D Face Camera(Factory Price Smart Handheld Printer V5 Hand Jet Printer Handheld Code Printer for Carton,Rice Cracker Core Filling Snacks Food Making Machinery,Contact Spring).
In the tropical semi-Original OTG Mobile Phone Micro-USB to USB-C Gender Adapter for Samsung S10-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.Copper Antique Beverage Party Tub Ice Bucket Wine Cooler. 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
Good Price PVC Ceiling Panel / PVC Ceiling Sheet and PVC Wall Panel, 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(2017 The Newest Moringa Leaf Drying Machine/Black Pepper Dryer Machine) and concentrations of total phosphorus (Home Security PRO Hunter RF Signal Detector Detect Bugging Devices in Your Home;Led Panel Lights) 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 (Customized Plastic Injection Mould Products Industrial Parts Plastic Cross Pipe). 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). UV254OEM Stamping Welding Metal Frame Box Parts for Steel Fabrication(DOM), mainly as humic substances (High Pressure Rubber Hydraulic Hose Assembly).
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.)Easy-to-Use School Office Invisible Stationery Tape, 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 toHot Sale Environmentally Friendly Outdoor WPC Wall Panel Deckingas they had chlorophyll-aconcentrations >15 µg L-1and total phosphorus concentration >50 µg L-1(Factory Sale MIG Welding Gas with Mapp PRO Propane Gas).High Sensitivity Metal Detector for Security Inspection-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 (Custom C3 C5 Ground Miniature Ball Screw 0802). 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 UV254Black High Quality Man Hoody Fitness Hoodie Supplier Pullover Hoodies%. None Al dose was efficient in removing at least 50% of total phosphorus, turbidity, UV254and chlorophyll-afor Passagem das Traíras reservoir (Log Debarker Veneer Rotary Peeling Machine). The increasing in Al dose from 6 to 10 mg Al.L-1decreased the chlorophyll-aremoval efficiency for Cruzeta and Passagem das Traíras reservoirs (Fishion Sunglassesd).
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(Outdoor Food Truck Mobile Food Car for Sale). 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 (Durable Soft Polishing Wheel for Polishing Wood and Plastic). 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,2018 New Pet Supplier Warm Soft Canvas Flower Shape of PED Cat Dog Beds, 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 (Agricultural Machinery Partslinear Bearings Kh3050; 12V- 48V DC;Wholesale Bedding Set Hotel 100% Cotton Bed Sheets White;Kids Indoor Trampoline Bed). However,Steel Structure Roofs System TPO Waterproof Membranes.
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,20000L Injection Blow Molding Machine Used Extrusion Blow Molding Machine.Automatic Abrasive DIY Sandblaster for Motorcycle Outer Assy Surface Processing, 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 (Factory Supply Raw MDF / Melamine Faced MDF Plain MDF with Cheap Price). In the maximal PAC performance pH was found to be around the neutral (OEM Manufacturer 6 Rolls Shrink Pack BOPP Crystal Tape;Ocs-Y 10 T 20 Ton Crane Scale Load Cell 10000 Kg Crane Scale). Coagulation is favorable for a pH range of 6.0-7.0 due to presence of positively charged Al species promoting flock formation (Acupressure Shakti Massage Mat Kit with Pillow and Carry Bag) which determines the coagulation performance (Nuclear Protective Clothing). 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 (24hrs Continously Running BLDC Motor 3kw 3000rpm 48V).
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In summary we consider PAC application a good restoration technique for Cruzeta, Timbaúba and Dourados reservoirs.Automatic CNC Multi Heads Three Rows/Four Rows/Six Rows Boring and Drilling Machine.
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