By Kar Munirathinam, CH2M HILL Principal Technologist
Dr. Munirathinam will be presenting the paper “’Beyond the Fenceline’ Approach for the Industrial Water Reuse in the Ravenna Area,” co-authored by Carlo Zaffaroni, Serena Cattaneo, and Mauro Marinetti, on Monday, October 1, 4:00-4:30, in Room 345 during WEFTEC. See a full list of CH2M HILL’s WEFTEC events and participation.
Ravenna, Italy, is a city with very stringent water discharge limits. In addition, a major industrial area, including a large petrochemical site, is located nearby, which requires large quantities of different quality waters. A total of 30,000,000 cubic meters per year (m3/y) of surface water is needed for potable/industrial use. CH2M HILL was hired by the two major stakeholders in the water distribution and collection systems of Ravenna to identify possible synergies that would improve conservation of surface water, as well as provide more sustainable use of land and other resources. The team performed a study that considered different reuse factors and water sources, the different needs of the treatment plants, modifications of treatment processes retaining most of the recent units and upgrade/replacement of the older ones, and economic aspects of each option.
The study consisted of three phases:
– A first screening phase to evaluate the existing situation and define project targets
– A second process phase to evaluate energy and mass balances of water and key parameters of three viable solutions coming from the initial screening
– A third phase involving process and basic design coupled with equipment, piping and layout definition, as well as preliminary cost estimate
The initial phase examined the current available water supply (surface water, municipal treated effluent, industrial treated effluent) as well as the demand (for potable use, for industrial use in the petrochemical area, and for industrial use in the second industrial area), both in terms of amount and quality.
The outcome confirmed the viability of producing high-quality reused waters and conveying them from the treatment plants to where they would be used, and defined a reliable supply of 1,000 m3/h from the municipal wastewater treatment plant (WWTP) for producing soft and demineralized water for industrial use.
During the second phase, process calculations and mass and energy balances were developed to model both the existing system and the new proposed one. The findings were summarized in the mass balance of the new proposed configuration.
The third design phase allowed further definition of the four main subareas:
– Transformation of one train of the municipal WWTP into membrane bioreactor (MBR), and related improvement of the remaining train
– Conveyance of the permeate to the petrochemical site
– Production of soft water at the petrochemical site with UV disinfection, nanofiltration (NF), and management of concentrates
– Conveyance of part of the NF permeate to the second smaller industrial area, with related modification for storage
The results showed that a “beyond the fenceline” approach produces a solution that will save 8,000,000 m3/y of surface water, decrease nitrogen discharged by the municipal wastewater treatment plant by 50 percent, and reduce the amounts of chemicals needed for treatment and sludge produced, all while reducing the treatment cost of the soft and demineralized waters produced. The defined solution will achieve the environmental, sustainability, and economic targets of the project.
I look forward to discussing the project further during WEFTEC, and encourage you to think about how you could lend this approach to water management in your community.
Dr. Munirathinam has over 30 years of experience in feasibility evaluation, bench-scale and pilot scale treatability studies, and process design of biological and physical/chemical systems treating waters and wastewaters including recycle/reuse applications. His specific nitrogen removal experiences include municipal wastewater treatment, refinery wastewater treatment, and pharmaceutical wastewater treatment including pilot studies and full-scale plant design. His experience also includes operations consulting and oversight, operations trouble-shooting, plant capacity evaluations, existing plant process modifications and upgrades, front end engineering designs, detailed design coordination, and start-up and commissioning of plants.Tags: CH2M HILL Access Water, industrial water reuse, water blog, water reuse, WEFTEC, WEFTEC 2012