Controlling of wastewater is really important. The control of water treatment includes sewage treatment and domestic wastewater treatment and it is referred to as the process of removing all contaminants from the wastewater. It includes chemical, physical and biological contaminants. The main objective is to create a waste stream also referred to as treated affluent and solid sludge or wastes that are suitable for reuse or discharge back into the environment. The wastewater is inadvertently contaminated with so many inorganic and organic toxic compounds.
The controlling of wastewater helps in pollution prevention. Through chemical reactions, physical and biological agents, the wastewater pollution could be minimized to very low levels. Wastewater causes so much pollution to air, other clean water and pollutes environment. The pollution caused by the wastewater has caused threat to health of people and also to wildlife. The wastewater control helps in controlling effluents and emissions into the air, soil or water. These effluents degrade the environment (Khopkar, 2004).
The raw sewage or influents include household waste liquid from baths, showers, sinks, toilets and kitchens. The sewage may also include wastes from commerce and industry. The draining and separation of the household waste into black water and grey water is much more common among the developing and developed countries. The grey water is then recycled and reused for watering plants or is used for flushing toilets. The surface water from hard-standing or from roofs is also known to be waste water. Some treatment processes that are used for storm water include wetlands, sedimentation basins, buried concrete vaults that has different kinds of votex separators and filters which help in the removal of the coarse solids. The process of wastewater treatment has three steps. In the first step, also called the primary treatment involves holding the waste water in the quiescent basin and all the heavy solids are allowed to settle at the bottom. The floating and settled materials are taken from the liquid and the liquid that remains is taken to the next step. In the secondary treatment the suspended and dissolved biological matter are removed (Hillman 1988).
This is performed by water-borne micro-organisms in a managed condition. The final step is the tertiary treatment where the water is disinfected physically or chemically by the use of microfiltration and lagoons before they are discharged into a river, bay, wetland, or stream. This water could also be used for irrigation of various and specified green way, golf course or a given park. This is a good example of how the waste water treatment helps reused again. This is another advantage of treating the water that is viewed and termed as waste. The water could also be clean enough such that it could be used for agricultural purposes or groundwater recharge (The straight dope 2001).
The major objective of treatment of wastewater is usually to allow industrial effluents and human effluents to be disposed off without any danger or pollution to human health or undesirable damage to the beautiful natural environment. The irrigation done with wastewater is both utilization and disposal and in fact it is an effective type of wastewater disposal meaning slow-rate land treatment. Nevertheless, varying degree of treatment should always be provided to the raw municipal wastewater even before it could be used for the landscape or agricultural irrigation or even for aquaculture. The good quality of the treated effluent that is used in the agricultural means has an enormous influence on the performance and operation of the aquaculture system or wastewater-soil-plant system. In regard to the case of irrigation, the necessary quality of the effluent depends on the crop or many crops to be irrigated, the system of the effluent distribution that is adopted, and the soil conditions. Crop selection and restriction of irrigation systems minimize the health risk, and also there is reduction in the degree of pre-application wastewater treatment. An analogous approach is not recommended and is not practicable in aquaculture systems and more reliance on control through wastewater treatment is encouraged (Khopkar, 2004).
The most suitable wastewater treatment that can be applied before the effluent can be used in agriculture is that it produces an effluent meeting that is recommended chemical and microbiological quality strategy both at low cost and with negligible maintenance and operational requirements (Arar 1988). Taking the low level of treatment should be as minimum as possible because it is especially desirable in the developing countries, not only from the point of view of cost but also in acknowledgement of the difficulty of operating complex systems reliably. In many places it will be necessary to design reuse system to recognize a low-grade of effluent other than to rely on the complex treatment processes that help to get a reclaimed effluent which usually continues to meet the stringent quality standard that is acceptable (Arar 1988).
Nevertheless, there are some locations where the effluent of higher-grade that is necessary and it is necessary that has adequate and necessary information on performance of an extensive range of wastewater treatment technology that is available. The design of the wastewater treatment plants is typically based on the requirement to reduce suspended solids and organic loads to reduce and limit pollution of the environment at large. Removal of pathogen has not been considered adequately as an objective but, could be used for reuse of effluents in the agriculture sector, this must however be of principal processes and concern and should be designed and selected accordingly (Hillman 1988). The treatment to remove the wastewater ingredients which may be harmful or toxic to aquatic plants (macrophytes), to crops and fish is theoretically possible but it is not usually economically feasible. Few performance data on the wastewater treatment plants more often in the developing countries are readily available and do not actually include the effluent quality parameters of significance to agricultural use (The straight dope 2001).
The short-term disparities in the wastewater flows that are observed at all the municipal wastewater treatment plants and they usually follow a diurnal pattern. Flow of the wastewater is characteristically low during the wee early morning hours of days, when the water consumption is at the lowest level. The base flows usually consist of very small quantities of the sanitary wastewater and infiltration inflow. The first peak of the flow usually occurs in the late morning hours, when the waste water from the peak morning water level use reaches the wastewater treatment plant and the second peak flow frequently occur in the late afternoon (Hillman 1988).
The relative magnitude of the various peaks and the frequent times at which they occur usually vary from nation to nation and with the length of the various sewers and also depends on the size of the community. The small communities with few sewer systems have an advanced ratio of peak flow to mean and average flow than the large communities. Even though the magnitude of peaks is accelerated as wastewater passes throughout a treatment plant, the day to day variations in the flow from a community treatment plant make it very impracticable, in most cases, to irrigate the lands with the effluent from the treated wastewater directly from the treatment plant. Most of the forms of short-term storage or flow equalization of the treated effluent is quite necessary to give a relatively constant supply of the reclaimed water for effective and efficient irrigation, even though additional profit results from storage (The straight dope 2001).