Organic Waste Recycling

Algal production 225

Figure 5.3 Spirulina “jeejibai”, showing tapering of end turns, (magnification × 600)

Contamination of toxic materials and pathogens

Possible contamination of algae with toxic substances (heavy metals, pesticides)
and pathogens, which are common in wastewater, will reduce the potential value
of the algal production.

5.2 ALGAL PRODUCTION AND HIGH-RATE ALGAL

POND

There are three possible algal cultivation and processing systems, depending on
the raw material used and the utilization of the obtained biomass (Becker 1981):

• System in which selected algal strain is grown using fresh water,
  mineral nutrients and additional carbon sources. The algae produced
  in such systems are utilized mainly as human food.


• System in which sewage or industrial wastewater is used as culture
  medium without addition of minerals and external carbon. In such
  system algal population consists of several species in the presence
  of high amount of bacteria. The main purpose of this system is
  wastewater treatment and biomass produced as feed for animals or
  as substrate for energy production.


• System where cultivation of algae in an enclosed system (fermenter)
  under sunlight or artificial light, with cells being grown in a
  completely autotrophic medium.