Common Problems Occurring In Sewage Treatment Plants And Their Solutions

The population is rising rapidly across the globe and rural areas to urban areas migration is also very high at present. This has put a lot of pressure on the sewage system that we have and now, there is this concept of Decentralised Sewage Treatment Plants. This is a great system that has helped a lot in solving this problem related to sewage, but at the same time, this is also a fact that maintenance related demands are always high. In the lack of proper and timely maintenance, they can face a number of problems and here in this article, we have discussed some of them along with their solutions. 

Downstream Equipment Failure Due To A Build Of Large Solids, Hairs And Fibres

Large solids and hair have always been the biggest issue for sewages and drains and at a large scale; this problem can be eradicated using the process of screening. The benefit of screening is that large screens can remove large particles, dirt, hair, debris, etc. that are basically non-biodegradable and floating. These large particles mainly include names like rags, paper, plastic, tin, containers and wood.

Timely and efficient removal of these particles is very helpful, as this will offer protection to the downstream plants and equipments from any possible damage, wear and tear and so on.

Treated Effluent Not Meeting Total Nitrogen (Tn) Targets

If this problem is occurring in your home sewage treatment plant, the first step you need to take is to determine the amount of ammonia present there along with nitrite and nitrate. This will let you know the areas, where you need to put in your efforts to make sewage treatment plant compliant to the local sewage related laws. This problem basically occurs because of high levels of ammonia present in there of high levels of nitrites both of them contribute towards high total nitrogen level.

High Ammonia

If the ammonia is high in the sewage treatment plant, you need to look for the following. 

• Nitrification occurs only under aerobic conditions at dissolved oxygen levels of more than 1.0 mg/L
• Nitrification requires a long retention time
• A low food to microorganism ratio (F:M)
• A high mean cell residence time (measured as MCRT or Sludge Age)
• Adequate pH buffering (alkalinity)

High Nitrate

If the nitrate levels are high, it is worth understanding that this happens due to the presence of bacteria that are capable of living in a low oxygen environment.

In this case, you will have to correct the following parameters, as they will bring nitrate at the right level in your sewage treatment plant.

• Adequate carbon source
• Ensure that the nitrification process is working
• Ensure that the anoxic tank has a DO = 0.0mg/l

Your Treated Effluent Is Not Meeting Total Phosphorus (Tp) Targets

According to the experts, to reduce the amount of total phosphorous in your sewage treatment plant, you will have to go for a number of chemical dosing options. However, all of them are possible only if jar testing has been performed that happens to be a critical step in terms of phosphorous measurement.  This jar testing will help you determine the most effective chemical needed for your process (e.g., alum or ferric chloride).