Causes for the overload of the WWTWs in developing countries.

What are the causes for the overload of the WWTWs (Wastewater Treament Works) in developing countries? How many countries have constructed new WWTWs since, they have started with development?

Taxonomy

• Treatment
• Wastewater Treatment
• Wastewater Treatment Plant Design
• Water & Wastewater

6 Answers

1. No consultation taking place before, constructing new houses, mall, and garages. And IDP not followed as usual.  

2. Overloading can either be due to excessive flow, excessive organic load, or both. There could be several reasons for this. Here are a few: (i) inadequate design - for flow or organic loading (ii) power outages - might cause some or all aeration, pumping and mixing systems to go offline, leading to transient overload (iii) unmetered industrial loads (iv) absence of online sensors and meters to provide real time, or advance warning of loads (v) lack of combined sewer overflow or diversion programs for extreme weather events - e.g., wet weather flows, monsoon rains, etc, and sometimes (vi) weak operator training & certification programs
   

3. There could be several reasons (i) plants receive more sewage than they were designed for (ii) in countries with power outages, aeration systems might fail to function for periods of time (iii) indequate provision for wet weather events and extreme weather conditions (iv) unmetered industrial discharges that increase the load (v) absence of online sensors - flowmeters, probes, etc - that provide advance or realtime warning on overloads and (vi) operator training
   

4. For documentation of WWTP performance in the United States check out the US Environmental Protection (USEPA) website, http://www.epa.gov/, for information. Similar information should be available for other countries.

5. Organic material in the waste that is too high for a system component or process causing clogging of the infiltrative surface of that component (i.e., sanitary wipes blocking a media filter) or a downstream component (subsurface soil absorption system) resulting in a hydraulic failure (effluent surfacing or backing up). would result in organic overload. And as said by Chris, poor maintanace and operation is a reason as well.
   

6. Poor operation and maintenance of wastewater and sewage treatment infrastructure is a cause for overloading. Also the design estimations are done without considering population explosion at many places.