Waste should not be your problem except for stuff used during cleaning. If the dealer doesn't take, you don't want it. IMO you should make that clear from the start.
I think this would be the way to go, ask users to remove gralloch, h&l, head, feet etc. before arriving at the larder. Most people will already have a way to dispose of this, on the stalking ground if remote and permitted, dog food and/or its easier to secrete into the black bin if in small quantities. Bulk waste disposal would be a nightmare and expensive.
But the whole things going to be expensive and risky.
@Dan Newcombe I think you should consider the cost in a simpler way that gets the thing up and running and leaves you as owner/organiser far less exposed financially. I'd forget about annual membership fees and cost per deer etc. Venison revenue should be a direct pass through, unless the member misbehaves then it can be forfeited.
For example if you recon it will cost £10k, allow for £15k of capital to allow for a slush fund for the first year's outgoings. Maybe you can get a grant of £5k? Apologies, just making up numbers here, I do not know if you have buildings already or would get a plug and play unit. Make it abundantly clear to prospective users that unless the cash is raised the thing won't go ahead. So at say 20 members/key holders, they would need to cough up £500 each to get to £10k.
At the end of the year, present the running costs and what is left in the slush fund, forecast what the costs will be next year and ask for each member to cough up 1/20th. You need to think of the process if a member wants to quit or be replaced. Like a shooting syndicate you'd need rules, a constitution and some form of dispute resolution procedure, maybe a local BDS rep or a retired lawyer.
If you are the owner/organiser, it will involve a lot of time, so it wouldn't be unreasonable for you to get free ongoing use. I know some game syndicates operate like this, where one person does most of the keepering.
Just ideas to consider.