I found a report on internet about how how some volunteer helped to clean Missouri River http://www.riverrelief.org/workspace/uploads/river-clean-up-manual.pdf I am not able to upload the PDF I have given the link

Cleaning up of the Singapore River is the best practical case study we have in this regard. Please see http://cdn2.iwahq.info/all/Specialist%20groups/Clusters/Smart%20Water%20Cluster/ASPIRE%20workshop/Smart%20Water%20-%20Singapore%20Case%20Study_aik%20num.pdf http://cdn2.iwahq.info/all/Specialist%20groups/Clusters/Smart%20Water%20Cluster/ASPIRE%20workshop/Smart%20Water%20-%20Singapore%20Case%20Study_aik%20num.pdf

Global practices for clean rivers

Some of the practices could be undertaken.

Buffalo River Restoration The cleanup falls within the lower six miles of the Buffalo River and the City Ship Canal. The project was designed to minimize impact on river users. Approximately 488,000 cubic yards of contaminated sediment will be removed using a clam-shell bucket. This is equivalent to about 33,000 truck loads. Monitoring will help make sure the water flowing downstream meets water quality standards. The material will be placed into barges and disposed of at the U.S. Army Corps

Attached file is foe waste water treatment process followed in U.K, Kindly follow same or similar to protect our rivers.