HERE'S HOW OUR SYSTEM WORKS
We bought a marine-quality 12 Volt Macerator pump from a Marine Supply store here in Sitka .
ITS' A JABSCO DRY-RUN PUMP THAT'S AVAILABLE THROUGH BOATING SUPPLY STORES...I THINK OURS COST US AROUND $170.00

It has an Inlet that's only 1-1/2  , so in order to make it work using standard 3"RV piping ... I picked up a 'Reducer' from a plumbing supply store. One end of it is 3" and it tapers down at the other end to 1-1/2 " . Then I needed to build a set-up that would go from 1" ( which is the diameter of the pumps outlet ) down to 3/4 " ( which is the size of garden hose we'll be using ) .  I picked up a section of very heavy-duty 1" hose , 2 hose clamps , 1 -1"plastic fitting designed to have its barbs inserted into the hose and at the other end is threaded ( female) with a 1" inside diameter . I also picked up a brass Bushing that would fit into the 1" female end of the plastic fitting ...the interior threading in this Bushing is 3/4". Then I found the correct sized brass fitting designed to screw garden hoses into it , that fit into the Bushing .

We want the pump set-up to be easy to store and 'Tidy' looking too . So I picked up a hefty orange box with great hinges and a excellent snap catch on it .  I placed the macerator pump in the Box and made marks where the outlet and inlet line would go . For the inlet side I used a 2" hole-saw attachment on my drill and drilled out the plastic on the box . Next I changed over to a 1-1/2 " hole-saw and drilled out the outlet hole . Then I placed the macerator pump back in the box and pushed it forward so the inlet portion of the pump was protruding from the box 2" and using a nail made marks through the 4 pump mounting holes ( at the base of the pump ) . I drilled out the 4 holes through the bottom of the box and inserted the rubber 'feet' onto the bottom of the pump and bolted it down securely into the box ( use wing-nuts , its easier to remove the pump for servicing later ) 

Now that the pump was bolted down in the box ... I cut a section from the heavy-duty plastic hose that's approx. 4" long . Good quality plastic hose is pretty stiff stuff ...so I soaked the piece in Hot water for about 5 minutes to soften it up a bit . Then I pushed one end of it over the Pumps 1" barbed outlet and used a hose-clamp to get a nice tight seal on it ...at the other end of the hose ( which protruded about an 1" from the box ) I pushed the 1" barbed fitting onto it and hosed clamped that down . Next I used plumbers tape to get a good seal on the bushing and screwed that into the end of the plastic fitting ...then I screwed the brass 3/4 garden hose fitting into the bushing . That's all you need for the outlet side ...its ready to attach a 3/4"garden hose to it .
Next I took the Rubber Reducer and placed the 1-1/2 end over the pumps inlet port and tightened it down securely ... all I need to do now is get a small 4" long section of 3" black plastic pipe , glue a RV hose adapter to it and add the 12 volt electrical leads . Since we have a marine 12 volt receptacle on the exterior of our bus , I'll wire up the leads to be able to plug-in there. I'm also wiring it up to use battery Alligator clips too , just in case something goes wrong with the exterior outlet. I'll be able to switch over to either wiring system easily because I'm using a marine 12 volt 2 pinned male & female plug setup in the box . All I'll have to do to switch from one system to the other is un-plug one line and plug the other one into it .
We also have a cover that is designed to snap over a garden hose that we'll use to close off the outlet on the pump ... and I'll use a 'Termination cap to close off the Inlet hose . 

I was 'searching' around on the 'Net' and found a system similar to mine that used a box to store the pump and its hoses in ....I was tempted to buy it . But , The inlet & outlet hoses looked pretty Flimsy . So , I decided to build this one myself with heavy-duty parts . I can't imagine anything more miserable and embarrassing then hooking up your Macerator Pump ...turning it on and having a hose burst ....a very messy situation indeed . The whole set-up here cost us a little over $200.00 , which is well worth it we think .
The set-up measures
18" long x 10" wide x 7" high

Here's a few pics of what my set-up looks like
 

CAMPING WORLD Sells a similar Macerator Pump to the one we used in our system...for around 
$161.10
Click-Here to see more about this Macerator Pump at Camping World

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