Environmental Management

, Volume 20, Issue 3, pp 361–374

Sludge-grown algae for culturing aquatic organisms: Part I. Algal growth in sludge extracts

Authors

  • K. M. Hung
    • Department of Biology & Centre for Waste Recycling and Environmental BiotechnologyHong Kong Baptist University
  • S. T. Chiu
    • Department of Biology & Centre for Waste Recycling and Environmental BiotechnologyHong Kong Baptist University
  • M. H. Wong
    • Department of Biology & Centre for Waste Recycling and Environmental BiotechnologyHong Kong Baptist University
Research

DOI: 10.1007/BF01203844

Cite this article as:
Hung, K.M., Chiu, S.T. & Wong, M.H. Environmental Management (1996) 20: 361. doi:10.1007/BF01203844

Abstract

This project is aimed at studying the feasibility of using sewage sludge to prepare culture media for microalgae (Chlorella-HKBU) and the use of the sludge-grown algae as a feed for some aquatic organisms. Part I of the project included results on preparing sludge extracts and their use on algal culture. By comparing two culturing techniques, “aeration” and “shaking,” it was noted that both lag and log phases were shortened in the aeration system. A subsequent experiment noted that algal growth subject to aeration rates of 1.0 and 1.5 liters/min had similar lag and log phases. In addition, both aeration rates had a significantly higher (P < 0.05) final cell density than that of 0.5 liters/min. A detailed study on the variation of growth conditions on the algal growth was done. The results indicated that pH values of all the cultures declined below 5 at day 12. The removal rates of ammonia N ranged from 62% to 70%. The sludge-grown algae contained a rather substantial amount of heavy metals (µg/g): Zn 289–581, Cu 443–682, Ni 310–963, Mn 96–126, Cr 25–118, and Fe 438–653. This implied that the rather high levels of heavy metals may impose adverse effects on higher trophic organisms.

Key words

Algal growthChlorellaHeavy metalsSludge extracts

Copyright information

© Springer-Verlag New York Inc. 1996