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Mass Balance Model for Sustainable Phosphorus Recovery in a US Wastewater Treatment Plant
Author(s) -
Venkatesan Arjun K.,
Hamdan AbdulHakeem M.,
Chavez Vanessa M.,
Brown Jasmine D.,
Halden Rolf U.
Publication year - 2016
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2014.11.0504
Subject(s) - biosolids , struvite , sewage treatment , environmental science , phosphorus , wastewater , enhanced biological phosphorus removal , sewage sludge , fertilizer , sewage , environmental engineering , waste management , activated sludge , chemistry , engineering , ecology , biology , organic chemistry
In response to limited phosphorus (P) reserves worldwide, several countries have demonstrated the prospect of recovering significant amounts of P from wastewater treatment plants (WWTPs). This technique uses enhanced biological P removal (EBPR) to concentrate P in sludge followed by chemical precipitation of P as struvite, a usable phosphate mineral. The present study models the feasibility of this enhanced removal and recovery technique in a WWTP in Arizona with design parameters typical of infrastructure in the United States. A mass balance was performed for existing treatment processes and modifications proposed to estimate the quantity of P that could be recovered under current and future flow conditions. Modeling results show that about 71 to 96% of the P being lost potentially could be recovered as struvite. About 491 ± 64 t yr −1 of struvite may be recovered after process modification, which corresponds to $150,000 ± $20,000 yr −1 in P sales to fertilizer industries. The process was projected to be economically feasible, with a payback period of 45 ± 30 yr in the studied WWTP and a much shorter duration of 3 ± 1 yr for WWTPs already using an EBPR process. Furthermore, modeling results suggest that P recovery can improve the quality of biosolids by favorably reducing the P:N ratio. Implementation of this strategy at US WWTPs may increase national security by reducing dependence of limited P resources. Considering all aspects of the recovery process with respect to environmental, economic, and social implications, the examined technique is concluded to represent a cost‐attractive and sustainable method for P management in US WWTPs. Core Ideas Mass balance model shows feasibility of sustainable P recovery in a US wastewater treatment plant. 491 tonnes/yr of P can be recovered as struvite from a single sewage treatment plant. Estimated P sales to fertilizer industries are valued at $150,000 per year. Estimated payback period as low as 3 yr for WWTP with existing enhanced biological P removal system. On a national scale, model predicts 16% potential reduction in P mining needs.