The standard purchasing process for Allegheny County involves: requisitioning; public solicitation; bid and proposal receipt; evaluation and contract award. This Article V includes specific standards for the design of subdivisions and land developments and requirements for improvements.Allegany County is soliciting a Request for. The Allegheny County Sewer Authority (ALCOSAN) is seeking proposals, through this. Construction Management. 18. This section contains instructions governing the proposals to be submitted and the material to be included in the proposal.