Environmental conditions and pathogen removal in macrophyte- and algal-based domestic wastewater treatment systems.
The environmental conditions and pathogen removal in macrophyte (Pistia stratiotes and Lemna paucicostata) and algal-based wastewater treatment systems were determined over a period of 29 days under tropical conditions. The experiment was conducted on a batch scale in 4.5 plastic containers immersed in moist sand beds. A control of raw sewage stored under dark conditions was included. Environmental conditions such as pH, temperature DO and conductivity and heterotrophic and faecal enterococci populations were monitored five times a week at 8, 12 and 20 GMT. BOD was monitored once a week for five weeks. Average temperatures within the systems ranged between 28.3 degrees C in the control to 30.6 degrees C in the algal-based system. Low pH levels of pH of 4.5 and DO levels of 3 mg/L were recorded in the water lettuce treatment systems. High pH levels around 10.5 and DO levels of about 20 mg/L were observed in the algal-based system. The control and duckweed system remained neutral. All treatment systems performed equally well in pathogen removal and BOD reduction. The BOD decreased from 130 mg/L to 5.0, 7.5, 10 and 15 mg/L in the duckweed, water lettuce, control and algal based treatment systems respectively. The faecal enterococci population decreased from 1.18 x 10(5) /ml to values below 100/ml in all treatment systems.
Awuah
E
E
Department of Civil Engineering, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Anohene
F
F
Asante
K
K
Lubberding
H
H
Gijzen
H
H
D029064:Araceae / Q000502:physiology*; D004755:Enterobacteriaceae; D056890:Eukaryota; D006863:Hydrogen-Ion Concentration; D010100:Oxygen / Q000378:metabolism*; D012722:Sewage; D013696:Temperature; D014865:Waste Disposal, Fluid / Q000379:methods*; D014871:Water Microbiology
D012722:Sewage; D010100:Oxygen