View Public Works' open solicitations, and learn more about how to register as a supplier and submit a bid or proposal. The Allegheny County Sewer Authority (ALCOSAN) is seeking proposals, through this.A brief narrative describing the proposed project. RFPs also guide bidders on how to prepare proposals. They may outline instructions on what information the bidder must include and the desired format. Include all features, structures, cost, assistance requests from Allegheny County and any request for machine work. The following items are site specific requirements of the project. A. Contractor to install the necessary materials and labor to complete the work identified.