Waste Water and Water Treatment Process

Waste water treatment:

Today's modern society need the treatment of waste water. The first modern treatment of the waste water by sewerage system was built by Lindley in 1842. He was born in Hamburg of Germany. He had mentioned ‘’how waste water is collected and transported to the treatment area’’ in his publication. Still, till now his many principles are used in the wastewater treatment process. The process of advanced wastewater treatment makes the water potable to drink or suitable to drink. To meet the rules of discharge, wastewater is cleared up by applying the process of primary, secondary and tertiary or advanced level of treatment. Mainly in our society, there are two types of waste water in a large quantity. They are:

1: Industrial waste water

2: Municipal waste water

Industrial waste water needs pre - treatment first before it discharged to the water sources because they are very hazardous to the environment. They must be treated well to remove non-compactable substances. For the treatment of the industrial waste water, different kinds of treatment process are applied. The most significant component of the industrial waste water is suspended solids. These suspended solid are organic in nature and they can be removed by the process of biodegradation. Some of the sources and contaminants are written as follows:

1: Suspended solids (S.S):

Sources of suspended solids are domestic, industrial, cause sludge problem, Soil erosion and infiltration in a flow. The environmental significance is it cause sludge problem prevails anaerobic conditions.

2: Biodegradable organic materials:

The main source of this wastewater contaminants is domestic and industries. These contaminants prevail the BOD.

3: Pathogens:

The main source is domestic wastes. These wastes cause the transmit of communicable disease.

4: Nutrients:

The main source of this kind of wastewater contaminants is domestic and industrial wastes. It causes the Eutrophication.

5: Refractory organics:

The main source is industrial wastes. It is carcinogenic in nature.

6: Heavy metals:

The main source is the industrial waste and mining. These are toxic in nature and cause many serious problems.

Water treatment process:

1: Dilution:

The process of the solution to the pollution is referred as dilution. This process is a very powerful method to minimize the pollution especially the suspended solution, total dissolved solids, biodegradable organics etc. These substances concentration is minimized if it is present in the excess water like river body, sea, stream etc.

2: Sedimentation:

The process of settling down the heavier particles is known as sedimentation. Particles size heavier than water settles down at the bottom. Solids that is collected at the bottom of the tank may be removed manually by periodically shutting down the tank and washing out the collected sludge. The effluent from the tank is then filtered.

3: Filtration:

One of the most widely used filtration for the water treatment process is the rapid sand filter which consists of a layer of carefully sieved sand on top of a bed of graded gravels. The pore openings between grains of sand are often greater than the size of the waste particles present in the water that is to be removed.

4: Disinfection:

The process which is used to make the water pure from all of the seeing and unseeing waste particles is called disinfection. Chlorination of the treated water by using chlorine gas, sodium hypochlorite is the most commonly used method of disinfection. Chlorine is a very powerful oxidizing agent that is easy to use which is inexpensive and reliable.

Wastewater treatment:

There is mainly three processes for the treatment of waste water they are as follows:

1: Primary treatment process:

It refers to the mechanical process to removes coarse sand, suspended solid etc. before applying to a primary treatment process for the waste purification pre-treatment is required. It reduces the bulk load of pollutants.

a: Avoid the damages to the sewer system.

b: It reduces the fees for its disposal.

In primary treatment process the following process is applied:

a: Screening; This process remove the pollutants which can block V-shaped notch wire of pipes and values.

b: Girth removal: This process removes the girth from raw sewage in early stage and prevents rupturing of the pump and other mechanical equipment. It avoids accumulation of inert solid in primary sludge by removing the girth heavy particles are removed out. The diameter of girth is 0.2 mm. All such types of particles along with suspended solids are removed out.

c: Sedimentation: Settling of sewage is to remove from waste water so as to reduce the load of the biological treatment units. The setting of the stage should be in the range of 1.25mm per hour. Sedimentation process removes coarse, suspended solids, BOD, refractory organics etc. The further treatment process can be done on some sedimentation tank by adding chemical substances.

2: Secondary treatment process:

Since much of the organic material in wastewater may be colloidal or dissolved primary treatment process only is insufficient or ineffective in doing the treatment. It is done by two ways; they are

a: Activated sludge treatment system:

Here in this process the wastewater is brought into the contact with the diverse group of microorganism in the form of flocculent suspension in an aerated tank

b: Trickling filter: In this process the wastewater is brought into contact with mixed microbial population in the clean of slime attach with the surface of solid surface of solid support medium. In both these case, the organic is metabolized to move stable inorganic form. That common unit operates on thickness, digestion, conditioning, dewatering, oxidation and finally disposal.

In this process, the wastewater is brought into contact with a mixed microbial population in the clean of slime attach with the surface of a solid surface of the solid support medium. In both these case, the organic is metabolized to move stable inorganic form. That common unit operates on thickness, digestion, conditioning, dewatering, oxidation and finally disposal.

In this process, the wastewater is brought into contact with a mixed microbial population in the clean of slime attach with the surface of a solid surface of the solid support medium. In both these case, the organic is metabolized to move stable inorganic form. That common unit operates on thickness, digestion, conditioning, dewatering, oxidation and finally disposal.

In this process, the wastewater is brought into contact with a mixed microbial population in the clean of slime attach with the surface of a solid surface of the solid support medium. In both these case, the organic is metabolized to move stable inorganic form. That common unit operates on thickness, digestion, conditioning, dewatering, oxidation and finally disposal.

3: Advanced waste water treatment:

During tertiary wastewater treatment process, phosphorus is removed out from waste water. If nitrogen and phosphorus concentration is excess in waste water, eutrophication problems may create. It takes place to;

a: Removal of suspended solid.

b: Nutrient removal ( nitrogen and phosphorus removal )

c: Removal of dissolved solid

d: Removal of inorganic material

These kinds of three methods can be applied for the treatment of waste water. If the waste water is disposed into the environment after its treatment they can cause less environmental effects. Environmental consequences cannot be seen. Among these three process of waste water treatment, the primary process is most commonly used because of its less cost. Whereas advanced or tertiary process is rarely used because of its high cost.These above-mentioned treatment process must be adopted by all before discharging them to make the eco-friendly.

References:

Miller, Jr. G.T. Living in the Environment. Wadsworth Publication, 2003.

S.C., Santee. Environmental Science. India, New Center: New Center Book Agency (P) Ltd, 2004.

T., Richard. Environmental Science Towards a Sustainable Future. India: PHI (P) Ltd., 2008.