Viability of combining microalgae and macroalgae cultures for treating anaerobically digested piggery effluent

Area of Science:

• Environmental Science
• Biotechnology
• Aquatic Ecology

Background:

• Anaerobically digested piggery effluent (ADPE) presents a significant waste management challenge.
• Algal phytoremediation offers a sustainable approach to treat ADPE, reducing nutrient pollution.
• Investigating the combined potential of microalgae and macroalgae for ADPE treatment is crucial.

Purpose of the Study:

• To evaluate the efficacy of microalgae and macroalgae, individually and in combination, for treating ADPE.
• To assess the growth performance and ammonium removal capabilities of selected algal species in ADPE.
• To determine the viability of co-cultivation systems for enhanced ADPE phytoremediation.

Main Methods:

• Bioprospecting of locally isolated macroalgae species, including Cladophora sp.
• Cultivation of a microalgae consortium (Chlorella sp. and Scenedesmus sp.).
• Evaluation of individual and combined algal treatments in different cultivation systems for ADPE.

Main Results:

• Cladophora sp. demonstrated effective ADPE treatment with a biomass productivity of 0.13 g/(L·day) and ammonium removal rate of 10.23 mg/(L·day).
• The microalgae consortium effectively treated undiluted ADPE (up to 525 mg/L NH4+) with an ammonium removal rate of 25 mg/(L·day).
• Microalgae and macroalgae failed to co-exist in combined systems, showing inversely related growth due to resource competition and physical interactions.

Conclusions:

• Individual algal species show promise for ADPE phytoremediation.
• Co-cultivation of microalgae and macroalgae is not viable for ADPE treatment under the studied conditions.
• Further research is needed to optimize conditions for potential mixed algal systems or to focus on single-species treatments.