Timothy J. Stohner, PE

Mr. Stohner is an MBA-educated licensed Professional Engineer with more than twenty-five years of environmental engineering consulting experience primarily in the Midwest and Mid-Atlantic regions. Mr. Stohner has managed and directed a wide range of projects, including air permitting; due diligence; soil, soil vapor, and groundwater remediation; and risk-based closures for real estate redevelopment. His clients include those in the Legal, Real Estate, Chemical, Industrial, Power Generation, Pipeline, and Public sectors. He is the current chair of the Environmental Committee of the Illinois Ready Mix Concrete Association.

• At an active hand tool and socket manufacturing facility, Mr. Stohner managed the troubleshooting and failure analysis of a chromium plating line after repeated upsets caused elevated total chromium concentrations in sanitary sewer discharge samples. He designed a new industrial pre-treatment system to receive oxalic acid-infused wastewater, batch-treat accumulated liquids from vibrating bowls, and then transfer liquids to a polymer injection system, clarifier, and (sludge) filter press. The system included pH adjustment using sulfuric acid and a mechanical mixer to prevent suspended particles from settling, which provided for uniform mixing. The chromium reduction occurred through sodium bisulfite addition controlled by oxidation reduction potential (ORP) monitoring to reach trivalent chromium levels. The resulting trivalent chromic sulfate was removed from solution by raising the pH to 8 by adding sodium hydroxide. The tank was then pumped out with an air diaphragm pump to the clarifier. The Ohio Environmental Protection Agency (OEPA) approved Mr. Stohner’s system design and issued the permit to install.
• At a now-closed and demolished foundry that used chlorinated solvents, Mr. Stohner planned and implemented a soil vapor extraction pilot test and analyzed the resulting data. He designed and installed a soil vapor extraction system with a 300-foot horizontal extraction pipe running parallel to the property boundary. He conducted emissions calculations and obtained a Wisconsin Department of Natural Resources (WDNR) air permit. Mr. Stohner’s system design uses an electric motor to extract soil vapors, which are treated with activated carbon prior to atmospheric discharge. A knockout tank is used to collect condensate, which is permitted to discharge to the sanitary sewers. The system has operated successfully for several years and is demonstrating a progressive source reduction.
• Mr. Stohner managed the remediation of an 11-acre former embossed cardboard box manufacturing site to be redeveloped into a multi-tenant retail center. As part of this multi-phase project, Mr. Stohner conducted a Phase I Environmental Site Assessment, supervised the removal of three 20,000-gallon heating oil underground storage tanks (USTs), and directed the removal of petroleum- and urban fill-impacted soils and the off-site stabilization of soils with hazardous levels of metals. Mr. Stohner directed site investigation and reporting activities and conducted risk-based modeling. Mr. Stohner’s analysis allowed for the installation of engineered barriers, including concrete floor slabs, asphalt pavement, geomembranes in landscaped areas, and areas of permeable pavers. The Illinois Environmental Protection Agency (IEPA) approved Mr. Stohner’s work and issued leaking underground storage tank (LUST) and Site Remediation Program (SRP) No Further Remediation (NFR) letters.
• Mr. Stohner managed the comprehensive site investigation, remediation, and risk-based modeling that allowed the transformation of a 35.5-acre site that housed manufacturing, research, and development facilities for an electrical component manufacturer into the site of new multi-family and single-family housing. As part of this project, Mr. Stohner directed the removal and recycling of former concrete floor and foundation segments and the disposal of over 1,000 tons of semi-volatile organic compound (SVOC)-impacted soils. Mr. Stohner conducted Tier 2 and Tier 3 modeling that resulted in an on-site groundwater use restriction, but also permitted the unencumbered construction of residential structures with concrete floor slabs and full basements. The IEPA approved Mr. Stohner’s work and issued a comprehensive NFR letter to allow for the residential construction to commence.
• Mr. Stohner has successfully designed, planned, and implemented multiple interim remedial actions across an over 200-acre active chemical terminal for an ongoing project subject to an IEPA Consent Order. This Site has had multiple historical releases of chlorinated solvents and petroleum products under prior management. These measures have included chemical injections and chemical/soil mixing to address soil saturation limit exceedances, excavations adjacent to bulk aboveground storage tanks and an active high-pressure jet fuel underground pipeline, and single- and dual-phase groundwater extraction and treatment systems. All soil treatment measures implemented by Mr. Stohner have been successful and approved by IEPA. Groundwater measures are demonstrating progress and are ongoing.