We're constantly nagged to not put wet wipes down the bog. I think the balance of cost and benefit depends on what it's been used for. If it's reasonably clean, yes, put it in the little bin in the bathroom. But what if it's got shit on it? In that case I think it should go down the bog. Benefits: hygienic; no need to put it in a plastic nappy bag; no chance of odours. Cost: it adds to the non-soluble material that has to be fished out at the sewage works. But what's the cost per wetwipe of that? A minute amount I should think.
Giving us all this hassle about wetwipes is just the water companies trying to make out they are heroes.
Bill