There are technologies (including robots) developed by Researchers in India. They may be in the nascent stage, but the governments (centre and state) have to give fillip to these technologies via funding, help them demonstrate and improve their products so that the practice can be reduced initially and then stopped.
it looks like pockets in Delhi and Kerala are testing this. But, that is not enough. It has to be done on a massive scale and everyone who employs such scavengers, either directly or indirectly (through contractors) should go for the technology solutions.
To start with, it could as simple as putting a fishing net like thing into the drains and lifting up whatever is possible, then draining out the water using pumps or something. i am not an expert in this, but just some thoughts off the top of my head.
Also, whoever is doing this manual scavenging, their families have to be taken care of by the governments, in terms of providing quality education of their children, food at reduced prices, quality medical tests and treatment (a weekly checkup) to name a few, until the manual process is stopped.
And whoever opposes the use of technology (politicians/contractors) citing job loss, should be strongly discouraged and jobs/contractors should not be given to them. For the laborers who do the manual scavenging can be taught how to use technology. more