Water and wastewater industry members must always prepare for the future. WWD Associate Editor Kristin Muckerheide recently discussed wastewater expansion planning for nutrients and flood mitigation with Jay M. Brady, P.E., principal environmental engineer at Stanley Consultants Inc.
Kristin Muckerheide: How can wastewater treatment facilities stay on top of uncertain and ever-changing nutrient requirements?
Jay M. Brady: Facilities need to stay aware of the nutrient policy and regulatory changes that seem to be frequently occurring. Facilities should consider studying nutrient removal alternatives for differing levels of nutrient removal requirements to give a full picture of what their potential upgrades and associate costs will be for a given effluent requirement. This level of service planning is especially important for those facilities in the process of planning an upgrade. Even if nutrient removal is not added to a current upgrade, a plan should be in place that allows for building and incorporating nutrient removal facilities into the existing plant.
Muckerheide: What goes into planning a plant expansion such as the one you recently spoke about in a presentation at Watercon 2012?
Brady: Planning an expansion such as Iowa City requires the planning team to gain a very good understanding of the owner’s needs, desires and constraints. A plan is the most successful when the owner’s requirements are integrated into the plan and the owner’s staff understands why decisions are made and the rationale behind the plan. A transparent planning process allows the owner to take ownership of the plan.
Muckerheide: What have been your greatest challenges on similar projects?
Brady: Resolving division within an owner’s planning team can be a significant challenge on any project. Using a transparent planning process will generally illuminate any major divisions, hopefully allowing resolution in a constructive way. Not everyone will always be pleased or in agreement with a planning outcome, but generally they will accept the plan if they fully understand the rationale behind [it]. Revisiting decisions can be another frustrating and challenging aspect of any project. Utilizing open decisionmaking processes that utilize mutually developed criteria with appropriate technical information can help minimize second-guessing decisions.
Muckerheide: How do you model a collection system or plant expansion to meet ammonia- and nutrient- removal objectives while considering emerging concerns?
Brady: Plant process modeling is an important component to determining a cost-effective and flexible plan for meeting near-term effluent requirements and anticipated emerging concerns. Plant process modeling allows various configurations to be efficiently sized and evaluated for process performance. “What if” scenarios can be examined to consider emerging concerns.
Muckerheide: How can facilities identify key concerns regarding flood inundation, and how can they develop a strategy to mitigate them?
Brady: I believe we are just beginning to recognize that our probabilistic-based flood prediction process has likely given us a false security in an age of climate change. Climate models are predicting— and we are likely seeing—more frequent and extreme storm events resulting in extreme flooding. Water and wastewater treatment plants are especially vulnera- ble to extreme flood events because they are often located on low-lying ground along streams and rivers. These facilities are critical to our cities and citizens and also are very expensive. As such, treatment facilities should be reviewed to verify their design flood levels and their components most vulnerable to flood.
Design flood levels should be revised as necessary based on the best available information. Consideration should be given to providing protection to the 500-year event plus 1 ft or to the 100-year event plus 3 ft to adequately safeguard this critical infrastructure. Multiple strategies are available for mitigating flood concerns, including barriers, raising critical mechanical/electrical equipment, sealing building/structure openings and raising walls.
Jay M. Brady, P.E., is a principal environmental engineer at Stanley Consultants Inc. Brady can be reached at [email protected] or 563.264.6322.
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