Standing Column Well

This is not practicle. 

Let me see if I got this right.  You say you have 3 -- 50hp sump pumps and you are hauling 0nly 250,000 gallons a day.  Next you say your basement fills with water 4'-6' deep.  That means your basement is about 62,000 square feet.  That includes 96" lally columns every 24' O/C. 

The only basement I know of that big has to be Ground Zero in Manhattan.  Nothing else even comes close.  It is set on the East River and that empties into Jamaica Bay.  I have some idea what your geology is.  It should be really hard granite.

You can't drill drywells into that mess even if it was legal to do it.  There are subway and utility tunnels criss-crossing all over the place.  Even if you could drill, granite won't absorb water. 

Look at a few options. 

1.  Set a purifier station where you are and use that water to feed the Con-Ed steam generators a few blocks away.  NYC is in good shape for drinking water but Con Ed draws a lot of that water to generate power and they have to de-ionize the drinking water so it dosn't clog their boiler tubes.  About the only thing that will jar loose those clogs is a ten gauge shotgun and a lead slug.  Con Ed sells the excess steam the generate to assorted buildings in the Five Boroughs anyway.  That might not use up all the water in the basement but it will spare the city that much drinking water.

2.  Set the same purifier and use the water for cooling towers in Brooklyn and Manhattan.  That means they don't have to buy water from the city and that will pay for pipes to run it.  There should be room for a 9" line from GZ to Brooklyn so there is no  cost for tunneling.  It is just the cost of the schedule-80 pipe, and that will be cheaper than the power you are using to pump.

3.  Talk to Con Ed again and set up a penstock and turbine system that will generate power for peak load use.  That will generate an extra 25-35 MW for your morning and evening peak draws.  It will take half again that much power to pump the water into penstocks but your peak load makes it worth considering.