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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
What does it really mean to optimize a water resource recovery facility (WRRF) for nutrient removal? Is it reducing costs? Reducing nutrient discharges? Can both objectives be simultaneously achieved? Nutrient optimization desires can stem from many causes but two main ones are permit requirements or preparation for downstream potable reuse. Increasingly stringent discharge limits typically come into play simultaneously with upgrades and expansions while transitioning from secondary treatment to advanced nutrient removal or during permit renewal. Likewise, when potable reuse is being considered, optimizing the upstream WRRFs for nutrient removal can help to minimize downstream potable reuse treatment costs.
Author(s)
Michael FalkJB NeethlingDave ReardonHolly Kennedy
SourceArticle of WE&T Magazine
Project IDWET20
SubjectNutrient Removal;Reuse;Design
Document typeMagazine article
PublisherWater Environment Federation
Print publication date Jun 2019
Volume / Issue31 / 6
Content sourceWE&T Magazine
First / last page(s)44 - 49
Copyright2019
Word count2,417
Subject keywordsWRRFCostNitrogen removalBODChemically Enhanced Primary Treatment (CEPT)

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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Defining the Costs
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Comparing WRRFs and optimization options requires defining which measures of what parameters are of interest. In this article, the unit cost metrics of interest are percent load reduction, dollars per liters per day, and dollars per kilograms of nutrient removed.
PublisherWater Environment Federation
Copyright2019
Word count112
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
WRRF Operating Cost Centers
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Figure 1 (p. 46) shows the typical operational cost distribution at WRRFs. The figure illustrates that energy and labor costs make up the highest distribution of annual cost. While chemical costs are listed as relatively low, they can be high for utilities that either routinely overdose or rely more heavily on chemicals.
PublisherWater Environment Federation
Copyright2019
Word count205
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Chemical Dose for Phosphorus Removal
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
The use of chemicals to precipitate phosphorus in primary clarifiers could have either positive or negative effects on WRRFs. The added chemicals reduce phosphorus while simultaneously capturing additional biochemical oxygen demand (BOD) and total suspended solids. These organics are redirected to solids processing where facilities with anaerobic digestion will produce additional biogas...
PublisherWater Environment Federation
Copyright2019
Word count94
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Energy and Capacity Effects by Implementing Nitrogen Removal
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Retrofitting a secondary process to a nutrient removal process is sometimes feasible. Because nitrification needs a longer solids retention time (SRT), it requires a larger basin. In addition, ammonia oxidation requires aeration (energy) and potentially an external carbon source to denitrify. Alkalinity may or may not be needed, depending on the situation. Some of the pros and cons are shown in...
PublisherWater Environment Federation
Copyright2019
Word count162
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Case Study No. 1 – Converting from Secondary Treatment to Nitrification–Denitrification
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
The Orange County Sanitation District (OCSD; Fountain Valley, Calif.) modified its P1-82 activated sludge facility (344 ML/d permitted capacity) operation from secondary treatment to nitrification–denitrification (NDN) to reduce ammonia discharged and sent to the Groundwater Replenishment System (GWRS) operated by Orange County Water District (OCWD). The facility successfully...
PublisherWater Environment Federation
Copyright2019
Word count427
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Case Study No. 2 – Regional Nutrient Assessment
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
In April 2014, the San Francisco Regional Water Quality Control Board (Water Board) issued a Regional Watershed Permit for 37 WRRFs discharging into five identified hydrologic subembayments. The permit requires that bay dischargers assess their nutrient loads and evaluate strategies for nutrient load reduction, should reductions be required in the future. The permit includes four key elements for...
PublisherWater Environment Federation
Copyright2019
Word count1,048
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Description: What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Careful Assessment
What Is the Cost for Optimizing a WRRF for Nutrient Removal?
Overall, the opportunities to reduce nutrient loads at WRRFs are wide-ranging and site specific. For WRRFs interested in optimizing their facility for nutrient removal, the listed unit cost metrics should serve as an initial guide that should be accompanied by a WRRF-specific detailed evaluation.
PublisherWater Environment Federation
Copyright2019
Word count259
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What Is the Cost for Optimizing a WRRF for Nutrient Removal?