BIOLOGICAL METHODS:
Wastewater derived from domestic, industrial and other activities is mostly hazardous to human beings,animals and plants so they must be treated prior to disposal . However conventional waste water treatment technologies are not effective, due to the high operational cost of the treatment processes and highly skilled technicians are required which adds to the cost. Current pre-discharge treatments of industrial waste water are routinely performed using energy intensive ,unsustainable low performance treatment technologies which utilize physical, chemical and partly biological treatment processes. Due to the presence of these compounds such as phosphorus,carbon, nitrogen and metal ions in waste water the treatment using conventional methods becomes ineffective and partially treated waste water remains undesirable for discharge. Chemical treatments involves the addition of high
Algal cells and some microbes use some metals by incorporating them into their which are used for various metabolic pathways.
Water hyacinth is a common inhabitant in lakes and ponds. This plant has been studied to have high levels of detoxification effects in water. It is capable of reducing heavy metals like cadmium, lead, mercury and nickel. It is also capable of degrading naphthalene in water biodies.
Algal sewage treatment : Employing algae for removing excess nutrient load from wastewater by construction of lagoons is an effective method. This method can be used in a very effective manner to treat sewage water and gradually decrease the amount of pollutants. In addition, micro- algae can be used in tests for toxicity and in the study of microbial ecology as they have indicators that are sensitive to minute changes that can be used to monitor ecological changes of water bodies.
Use of a series of these techniques in an orderly manner in such a way that the toxicity in