05-11-2012, 05:57 PM
QUENCHING THE THIRST OF MILLIONS IN THE WORLD- APPLICATION OF PROCESSED MORINGA OLEIFERA SEEDS IN DRINKING WATER TREATMENT
QUENCHING THE THIRST.ppt (Size: 329 KB / Downloads: 105)
INTRODUCTION
Drinking water which should be palatable and potable is essential to the health and welfare of a community and water from all sources must have some form of purification before consumption.
About 1.2 billion people still lack safe drinking water and more than 6 million children die from diarrhea in developing countries every year.
Water borne diseases still kill on the average 25,000 people every day in developing countries while millions suffer the debilitating effects of these diseases.
About 75% of the present world population live in the developing countries of the world.
About 80 % of all illnesses in developing countries are water related e.g. cholera, dysentery, diarrhea etc.
WATER TREATMENT OVERVIEW
Various methods are used to make water safe and attractive to the consumer.
The method employed depends on the character and source of the raw water e.g. surface water, groundwater.
For surface water, coagulation-flocculation followed by sedimentation, filtration and disinfection, often by chlorine, is used worldwide in the water treatment industry before distribution of the treated water to consumers.
Groundwater if too hard will have to be softened by using lime, soda ash, ion-exchange etc. to treat it.
WATER TREATMENT PROBLEMS
Water treatment companies in in developing countries face a myriad of problems
Some of these are:
Large seasonal variation in raw water quality e.g. turbidity.
Water treatment chemicals are imported with scarce foreign currency.
High cost of water treatment chemicals which constitute between 35% to 70% of recurrent expenditure.
Inadequate supply of chemicals for water treatment
Inadequate laboratory facilities to monitor process performances required to operate the plants.
Inadequate funding
Low revenue base
Water supply considered as a social commodity rather than an economic resource
Inadequate skilled manpower,
Poor operational and maintenance schedules,
Adoption of inappropriate technology.
Inadequate supply to meet growing demand
Underdosing of chemicals leading supply of poor quality water.
PROBLEMS FACED IN THE USE OF CHEMICAL COAGULANTS
There is also the problem of reaction of alum with natural alkalinity present in water leading to reduction of pH and a low efficiency in coagulation of cold waters.
Under-dosing of chemicals so as to meet the increasing water demand leading to production of poor quality drinking water.
Using alum as well as other metallic salt coagulants produces large sludge volumes which are also non-biodegradable.
Ferric salts and synthetic polymers have also been used as coagulants but with limited success because of the same disadvantages manifested in the use of aluminum salts