Ready-Mix Recycle Pits

Many ready-mix concrete plants struggle with stormwater runoff from their site due to the cement particulates causing a very high pH. Additionally, they strive to maintain high efficiencies with material input and output to maximize profitability. Ready-mix trucks often return to the plant after deliveries with a small amount of concrete mix left in the drum that needs to be washed out in preparation for another load. For this purpose, some concrete plants install recycle pits where the trucks can get washed out after a delivery or at the end of the day.

Commonwealth Engineers, Inc. recently completed the design of a new washout and recycle pit system for Ozinga’s Crown Point ready-mix plant. The pits were designed to receive the stormwater runoff from most of the plant site as well as any washout materials from delivery trucks. Additionally, the pits function as settling tanks to allow dust and cement particulates to settle out. The clarified water is then pumped back into the plant to be used in additional concrete mixes, as the high pH recycled water does not adversely impact the concrete mix.

The capturing of rainwater and the recycling of washout waste has provided significant savings on both the water and wastewater bill for the plant. Water demand of the utility has decreased since the use/reuse of the rainwater and runoff, and wastewater surcharges from the utility for the alkaline rich effluent have now been eliminated. For more information on this project, contact Andrew Robarge, P.E. or Ryan LaReau, P.E.

* Pictured – Ozinga’s Crown Point Plant