Hybrid algal photosynthesis and ion exchange (HAPIX) process for high ammonium strength wastewater treatment

Meng Wang, Karl A. Payne, Shuang Tong, Sarina J. Ergas

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


A hybrid algal photosynthesis and ion exchange (HAPIX) process was developed that uses natural zeolite (chabazite) and wild type algae to treat high ammonium (NH4+) strength wastewater. In the HAPIX process, NH4+ is temporarily adsorbed from the liquid, which reduces the free ammonia (FA) concentration below the inhibitory level for algal growth. The slow release of adsorbed NH4+ subsequently supports the continuous growth of algae. In this study, a HAPIX reactor reduced NH4+-N concentrations in centrate from an anaerobic digester from 1180 mg L−1 to below 10 mg L−1 without dilution. Chabazite doses of 60 g L−1 produced more algal biomass, with higher protein and starch contents, than doses of 150 g L−1 and 250 g L−1. Approximately 67–70% of fatty acids in the algal biomass harvested from HAPIX reactors were unsaturated. A mathematical framework that couples a homogeneous surface diffusion model with a co-limitation algal kinetic growth model reasonably predicted the algal biomass production and NH4+-N concentrations in the HAPIX reactors. The HAPIX process has the potential to serve a two-fold purpose of high NH4+-N strength wastewater treatment and agricultural or commercial biopolymer production.

Original languageEnglish (US)
Pages (from-to)65-74
Number of pages10
JournalWater Research
StatePublished - Oct 1 2018

All Science Journal Classification (ASJC) codes

  • Water Science and Technology
  • Ecological Modeling
  • Pollution
  • Waste Management and Disposal
  • Environmental Engineering
  • Civil and Structural Engineering


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