On October 17th Mr. Jay WeatherBee joined for a discussion on his 20 years of work in the wasterwater management field and his currently job at Veolia water. Mr. weatherbee currently works at a wastewater treatment facility where he is in charge of day to day activities which include mechanical upkeep and dealing with municipal politics. Mr. Weatherbee was kind enough to give us valuable information on the Treatment process which occurs in the typical plant.
Pre-treatment
The process begins when water from sink, toilets, sewers, and many other sources enters the head works building. In the head works building the first process to occur is screening, this removes roots, rags, cans and large debris from the inflow. These items are hauled to a landfill or if possible ground down and returned to the plants flow. The next step is known as grit removal, this removes sand and gravel from the flow and helps to decrease wear on machinery. The Next step is pre-aeration it is used primarily to remove grease and other oils from the waster water, as well as to further freshen the water. The last pretreatment step is flow meter, this process is essential to effective and economical use of the station in treatment.
Primary Treatment
The only step in the primary treatment is Sedimentation and Flotation, this process includes wastewater being pumped into tanks where the solids are allowed to settle. On the bottom of the tank there are usually special mechanism which push this sludge into a collection unit for further treatment, while oil and grease are allowed to rise and are skimmed off.
Secondary Treatment
The first step in secondary treatment is also the last in primary treatment its is the handling of waste solids in the tanks. In order to dispose of this solid aerobic bacteria and microbes are called into action these two combine to eat the solid and do most of the work. In order to promote bacteria production many tanks have air pumps which guarentees a plentiful oxygen supply for the bacteria. Some anaerobic digestion processes are also used these produce methane which is then pumped into boilers and used to produce electricity. This process is also known as activated sludge which refers to the activated bacteria in the sludge eating away and disposing of the solids and disolved solids thru natural processes. The last step is disinfection this step is used to kill pathogens which cause disease which may have escaped the previous processes, they include typhoy, cholera, and dissentary. There are two methods of disinfection mainly in use today they are ultraviolet light, and sodium hypochlorite. Both have advantages and disadvantages which have to be weighed before they can be choosen for use. Ultraviolet light is very effective but requires a huge amount of energy use and can be very costly, which causes many political and social issues because of its use. Sodium hypochlorite is a cheaper solution when disinfecting but can cause residual effects in recieving stream so sodium bisulfite must be added to the waste waste to neutralize any residuals. The last step in this process is the outflow of effluent into a recieving stream or out through disfusers. These release points are regulated by the EPA/DEM and each plant has to remove different things from influent based upon location of release. The level are regulated by state and federal departments.
Conclusion th
Mr. Weatherbees discussion discussed some very interesting point in the process of wastewater treatment from beginning to end. His discussion on the use of biological process was especially interesting, showing us how understanding and taking advantage of chemical reaction can be very beneficial. The next point i found very interesting was Mr. Weatherbees discussion of the politics behind building a waste water treatment facility to its function and its discharge. Throughout the process the issue of money hinders activity and the bureaucracy of dealing with organizations at the state and federal levels can cause some real troubles. Lastly Jay’s discussion of Permitting was very interesting but did make a lot of sense, each station had to remove certain compounds, or materials this was based on their location and was very important based on where the outflow was being released so it would as little effect on the environment there as possible.