11/21/11
A. Robert Rubin
Professor Emeritus
Biological & Agricultural Engineering
North Carolina State University
In a global perspective, wastewater reuse is a fledgling supply, but an important emerging source of supply. Only a very small portion of water is planned reuse – all water is returned to the water cycle and ultimately reused, but planned reuse is small. Legislation like California Title 22, the North Carolina 2U standards, EU standards and standards like those proposed as NSF 350 are helping raise the bar for reuse. A decentralized system allows recycle and reuse as close to potential users as possible and this reduces the energy required in a system. That can mean significant savings because the energy demands associated with moving water are quite significant. A distributed or decentralized approach reduces the disruption necessary to supply water, and can mine water from a collection system and use it through small, appropriately sized systems. The greatest challenge for us working with reuse is to create a vision where we cultivate building owners, operators, managers, and officials with an idea of how the future infrastructure of reuse can look.
rubin@ncsu.edu
Dr. Rubin gav everyone homework. Go to the EPA website and then email the answer to 3 questions. Please share your questions and his responses here so your classmates can see as he has been giving you good leads for follow up. Dr. T
ReplyDeleteTopic: "Corrosion in wastewater treatment plant"
ReplyDeleteQ:
It is estimated that the annual operation and maintenance costs associated with wastewater infrastructure to be in excess of $25 billion. Corrosion targets steel piping, tanks, concrete, transfer lines and pumps.
The most important mechanism in corrosion of component in wastewater treatment plant is Microbiologically Induced Corrosion (MIC) by hydrogen sulfide.
R:
Yes corrosion is a very costly issue, both in the treatment works and in the collection system. H2S is the culprit...Some interesting work on-going to control corrosion with new materials (plastic and fiber-glass).
According to the US EPA, onsite/decentralized WWTPs serve approximately 25% of the US population and 40% of new development. While the function of these systems are important, on the other hand, the current failure rate of the onsite/decentralized WWTPs is also very high, which makes them significant contributors of pathogens and nutrients. Nevertheless, the EPA determined that the decentralized systems can be promising for public health and environment with the current technology development and adequate management. Dr. Rubin’s talk has been focused mainly on introducing the benefits and current developments of the onsite/decentralized systems. The decentralized systems can improve energy efficiency of water conveyance and delivery, and also enable onsite water reuse. However, they may need more materials for system construction and operation. There is definitely a tradeoff between the centralized and the decentralized systems, but there is a lack of studies looking at this tradeoff in terms of life cycle environmental impacts. There is a gap to be filled in here in the future.
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