My view of off-main sewage waste - "Submission"
Understanding treatment of waste at a sewage plant
The way a sewage treatment plant works is fairly simple and easy to explain. Most people can imagine how dirty water comes into the front gate through a series of pipes, and then exit through another pipe down in a river after having been cleaned through a series of processes, being made clean enough to be left in nature without having an important environmental impact. But few people realize how much technology and processes are involved in the removal of these substances. Once the chemical separate the clean water from extra waste, usually ending up at the bottom of a tank, what exactly happens to this waste? In reality there are a number of ways to deal with the sludge, the waste remaining after water passes through a plant. Here are some of the most common ways sludge is dealt with. For information on sewage treatment click the link to an online resource.
The first method that can be used is a fermentation process called anaerobic digestion. This is a method that uses bacterias in order to basically eat up all of the waste in the absence of oxygen. Because those bacterias have to eat in order to survive, they eat the sludge away over a period of a few days, and can reduce the total weight remaining by a large percentage. In the case of biological waste, like what most of the sewage system transports, this is a very useful and efficient solution. Another method is aerobic digestion, which uses the same principle but this time with oxygen. This costs more because for the process to be successful the right amount of air has to be balanced into the system. However under the right conditions, this process is faster than the first method, so modern plants often opt for this strategy instead. Both of those systems are fairly common in modern plants, however they cannot be applied to every type of waste.
Just like people can create compost at home in small quantities, a sewage treatment plant can also produce compost in a much larger quantity using a process called composting. This takes a lot longer, often months, but is a much more natural process. Also, after the process is done, then the result can be sold to farms and other industries who can then use this compost. Incineration is by far the cheapest and simplest way to deal with sludge, however it is also the least environmentally friendly. This is what plants used to do in the past, but modern facilities try to avoid this system because of the bad impacts it can have. Finally, sludge can also be disposed of in landfills. This is also a method that has impacts on the environment but less so than incinerating, since only a small section of soil is contaminated. In the case of some substances which cannot be consumed by bacterias or used in compost, often this is the only outcome. Those are the methods used by sewage plants these days, with new advances being applied constantly.
This article i was given by my friend in civil engineer industry, i take no ownership. He asked to put it on my blog to gain feedback for him.