Table of Contents
What is jar test used for?
Jar test is a pilot-scale laboratory test that simulates coagulation or flocculation with differing chemical doses. The purpose of the jar test is to estimate the minimum coagulant dose required to achieve certain water quality goals.
What are the two objectives of jar tests?
The objectives of the jar test experiment are to estimate the optimum concentration of aluminum sulfate for the removal of suspended matter and to investigate the change in alkalinity as a result of aluminum sulfate addition.
When doing a jar test how long should you let the mixture set to determine how it may react in the tank?
Let the solution stand 15 minutes after the last shaking. Shake again and observe the results. If the materials are physically compatible, the jar will be cool to the touch and there will be no separation of materials or forming of clumps or emulsions.
What two chemicals are commonly used as water coagulants?
Aluminum sulfate (alum) is the most common coagulant used for water purification. Other chemicals, such as ferric sulfate or sodium aluminate, may also be used.
How is BOD removed from wastewater?
Some BOD is removed in the septic tank by anaerobic digestion and by solids which settle to the bottom of the septic tank, but much of the BOD present in sewage (especially detergents and oils) flows to the leaching field. The bacteria in a healthy biomat also digest most of the remaining BOD in the sewage.
What is the purpose of rapid mixing?
Rapid mixing aims to instantly and efficiently disperse coagulant species into raw water, before flocculation, sedimentation, and filtration processes. Mechanical mixing with a longer retention time cannot guarantee an instantaneous and uniform coagulant dispersion.
What happens during coagulation?
Blood clots and coagulation Blood vessels shrink so that less blood will leak out. Tiny cells in the blood called platelets stick together around the wound to patch the leak. Blood proteins and platelets come together and form what is known as a fibrin clot. The clot acts like a mesh to stop the bleeding.
Why is alum added to the water?
In a typical water treatment process: Alum is used to coagulate suspended particles, algae, protozoa, viruses, bacteria, and some metal ions (such as iron and manganese) into larger particles. Chlorine is added to kill bacteria that may have entered the water during the filtration process.
What are the 4 steps of water treatment?
These include: (1) Collection ; (2) Screening and Straining ; (3) Chemical Addition ; (4) Coagulation and Flocculation ; (5) Sedimentation and Clarification ; (6) Filtration ; (7) Disinfection ; (8) Storage ; (9) and finally Distribution. Let’s examine these steps in more detail.
What is a secondary or biological treatment?
Secondary wastewater treatment processes use microorganisms to biologically remove contaminants from wastewater. Secondary biological processes can be aerobic or anaerobic, each process utilizing a different type of bacterial community.
Is procedure for water analysis?
pH Testing Procedure Rinse each test tube with the water sample. Fill the tube to the 5mL line with sample water. While holding a dropper bottle vertically, add 10 drops of Wide Range Indicator Solution. Cap and invert several times to mix. Insert the tube into the Wide Range pH Comparator. Record the pH value.
Is FeCl3 a coagulant?
Ferric chloride (FeCl3) is the most common iron salt used to achieve coagulation. Its reactions in the coagulation process are similar to those of alum, but its relative solubility and pH range differ significantly from those of alum. Both alum and ferric chloride can be used to generate inorganic polymeric coagulants.
What is the process of flocculation?
Flocculation is a process by which a chemical coagulant added to the water acts to facilitate bonding between particles, creating larger aggregates which are easier to separate. The method is widely used in water treatment plants and can also be applied to sample processing for monitoring applications.
How the coagulant works in jar test?
The jar test involves exposing same volume samples of the water to be treated to different doses of the coagulant and then simultaneously mixing the samples at a constant rapid mixing time. The microfloc formed after coagulation further undergoes flocculation and is allowed to settle.
What full scale processes are stimulated when conducting the jar?
n the drinking water field, the jar test is described as a “bench-scale” simulation of full-scale coagulation/flocculation/ sedimentation water treatment processes.
Which is the biological treatment unit?
Biological treatments rely on bacteria, nematodes, or other small organisms to break down organic wastes using normal cellular processes. Wastewater typically contains a buffet of organic matter, such as garbage, wastes, and partially digested foods. It also may contain pathogenic organisms, heavy metals, and toxins.
How do you calculate chemical consumption?
Chemical Feeding Chemical used, lbs per day = Flow rate, MGD x chemical dosage, mg/L x 8.34 lbs per gallon. Chemical, lbs/day = (Flow rate, MGD)(chemical dosage, mg/L)(8.34 lbs/gal) Chemical dosage, mg/L = (Chemical, lbs/day)/(Flow rate, MGD)(8.34 lbs/gal).
What are the side effects of biological therapy?
Side effects of biological therapy Skin rash, redness, itching and dryness. Fever. Chills. Nausea. Vomiting. Loss of appetite. Extreme tiredness (fatigue).
What is the difference between flocculant and coagulant?
Flocculants differ from coagulants in that they are often polymers, whereas coagulants are typically salts. Generally speaking, anionic flocculants are used to catch mineral particles while cationic flocculants can capture organic particles.
How is jar test calculated?
0.1 gram and dissolve in 1000 ml distilled water. Calculate the volume of a 1 % Ferric Chloride solution that would be added to get the dosage required. A jar test indicates that the required amount of phosphorus removal can be achieved using a dosage of 3 ml of a 1% ferric chloride solution in a liter of wastewater.
What is coagulation of water?
Coagulation is the chemical water treatment process used to remove solids from water, by manipulating electrostatic charges of particles suspended in water. This process introduces small, highly charged molecules into water to destabilize the charges on particles, colloids, or oily materials in suspension.
