Coagulation and Flocculation in Water and Wastewater Treatment

It is a chemical reaction where the colors of both solution and iron strip changed. It is

In reference to the analysis of anions, Table 1 shows that a precipitate was formed when our unknown was combined with HNO3 and AgNO3, thus indicating the presence of a chloride ion. Because our unknown did not form a precipitate due to HCl and BaCl2, separate, effervesce, or smell, we concluded that neither sulfate, nitrate, carbonate nor

The objective of this experiment will be to combine various substances, liquids and metals, and to observe their behavior when they are combined. The types of reactions observed shall determine the nature of these reactions: physical or chemical.

Solutions of 6M H2SO4, 6M NH3, 6M HCl, 6M NaOH, and 1.0 M of NaCl, 1M Fe(NO3)3, 1M NiSO4, 1M AgNO3, 1M KSCN, 1M Ba(NO3)2, and 1M Cu(NO3)2 were given in separate test tubes. The color of possible precipitates, ions, acid-base behaviour, odor and solubility rules were conducted and were reported in Table 1. The key information about a mixture of two solutions was

When these components are mixed with the water, this causes the tiny particles of soil to stick together or coagulate. These particles are now bigger and heavier, they are known as flocs which makes it easier to remove by settings of filtration.

In part 1, the precipitate that forms is a aluminum hydroxide and in part 2 it is magnesium hydroxide. A precipitate is an insoluble solid that emerges from a liquid solution. When the emergence of the insoluble solid from solution happens, it is called precipitation. The property change in the reactants of the lab are when the water, alum, ammonia, react and create the aluminum hydroxide. When the precipitate is formed, it is an endothermic reaction because the change in the product, aluminum hydroxide, decreases in temperature. This is a chemical reaction because different elements rearrange themselves to form a new substance and while they do so, they either absorb heat or give it

The first reaction involves pyrite rock reacting with oxygen (air) and water to produce dissolved ferrous iron, sulfate, and acidity. The second reaction oxidizes the dissolved ferrous iron in acidic conditions and produces ferric iron and water. The third reaction involves the hydrolysis of the ferric iron to form ferric hydroxide and more acid. The ferric hydroxide is the orangey-red colored solid you see in the water (Juniata College).

The main objective of this experiment is to carry out qualitative analysis to identify metal cations in unknown solution 1.

The cations in both the known and unknown samples were identified by using qualitative analysis, of which were determined to be acidic, basic, or neutral by using litmus paper. Acid-base reactions, oxidation-reduction reactions, and the formation of complex ions are often used in a systematic way for either separating ions or for determining the presence of specific ions. When white precipitate formed after adding hydroxide, aluminum ion was determined to be present in the solution. However, nickel was determined to test positive when the solution changed to a hot pink color after adding a few drops of dimethylglyoxime reagent and iron was present when the solution was a reddish brown color when sodium hydroxide was added to the mixture at the very beginning of the experiment. Qualitative analysis determines that ions will undergo specific chemical reactions with certain reagents to yield observable products to detect the presence of specific ions in an aqueous solution where precipitation reactions play a major role. The qualitative analysis of ions in a mixture must add reagents that exploit the more general properties of ions to separate major groups of ions, separate major groups into subgroups with reactions that will distinguish less general properties, and add reagents that will specifically confirm the presence of individual

The second step of water treatment process is aeration. At the aerator, raw water is mixed with air. The aeration process helps to provide oxygen to the raw water which is needed for the oxidation process of dissolved iron and manganese in order for it to precipitate and therefore enables its removal through filtration (SAJ Holdings Sdn Bhd., n.d.). Wormleaton and Tsang (2000) stated that for water treatment process and also natural streams, it is essential to maintain a high amount of dissolved oxygen. Aeration also provides the escape of dissolved gases, such as carbon dioxide and hydrogen sulphide to reduce the corrosiveness of water, thus controls the tastes and odors of the water (Shun, 2007). Groundwater with high dissolved carbon dioxide levels or high concentrations of iron and manganese commonly require aeration as well as water drawn from reservoirs that is low in dissolved oxygen.

The particles suspended in natural surface water are thermodynamically stable, meaning that the particles will remained suspended in the water indefinitely if nothing is changed. While there is the possibility of instable particles in natural water, for example a grain of sand suspended in a fast-flowing river will settle to the bottom when the current slows down, it is safe to assume that the majority of the particles in the water are stable. The cause of this stability is static electricity. Particles in natural waters are coated with macromolecules called natural organic matter(NOM), which are produced by the decomposition of organic matter such as leaves, living organisms, aquatic plants, etc. Natural organic matter has functional groups that at neutral pH’s are negatively charged, giving the overall charge of the particles. Because all of the particles are negatively charge, they are repelled by one another so that the particles cannot collide and stick together to form larger and larger particles. Therefore, the goal of the first process in drinking water treatment, coagulation, is to destabilize the particles and allow them the potential to collide and stick together.

In this investigation, the influent is domestic wastewater collected and treated at the Luggage Point (LP) Wastewater Treatment Plant (WWTP), Brisbane - Australia. Experimental trials are conducting with a stream of raw sewage, which is passing through a common inlet works where screening and coarse solids reduction occurs before treatment distribution. The inlet

During primary treatment, pretreatment is performed which involves the usage of bar screens to remove large solids from the wastewater. The water is then pumped to pre-aeration tanks where grit (sand, eggshells, etc.) is removed. Next, the wastewater is fed to a primary clarifier where suspended solids are allowed to settle (primary settlement). After the primary clarifier, the wastewater still contains high amount of organic content and should be sent to secondary treatment. During the secondary treatment, the organic content of the wastewater is degraded by microorganisms within the aeration tanks, and waste sludge is allowed to settle in the secondary clarifiers. Sludge that settles on the bottom of the primary and secondary clarifiers is pumped to a digester via a sludge thickener to produce methane and carbon dioxide [4]. However, the water leaving the secondary clarifier still contains significant amounts of nitrogen and phosphorus. Also in this process, there is no special method employed during the treatment cycle to remove heavy metals from wastewater.

The disposal of untreated wastewater coming from the industries into the water bodies will pollute the water bodies because of its high concentrations. So, the wastewater produced from the industry should be treated properly to meet the permissible limits given by central and state pollution control boards. Therefore it is necessary to treat the wastewater properly with the help of an appropriate treatment plant. However, the treatment plant even though properly planned may not work satisfactory because of several reasons. Hence, it is essential to evaluate the treatment plant considering individual treatment unit in the entire treatment flow. In the present work emphasis has been given to the study of the performance of treatment facilities because of its importance in the conventional treatment of wastewater. Hence, the literature review related to the evaluation of the entire treatment process along with biological treatment process particularly suspended growth process Activated Sludge Process (ASP), attached growth process Trickling Filter (TF) and a combination of the both suspended and attached growth process Hybrid Reactor (HR) is presented in the following sections of this chapter.

Coagulation is the process in which colloidal particles and other fine suspensions are destabilized or neutralized to agglomerate induced by addition of inorganic chemicals(Tripathy and Ranjan De 2006). Electrostatic patch mechanism is adsorption of polymers onto local sites of a particle, causing patches of local charge reversal resulting in