Integrated natural treatment systems for developing communities: low-tech N-removal through the fluctuating microbial pathways.
Integration of natural treatment systems (NTS) (WSP, wetlands etc.) with each other as well as with advanced unit processes (biofiltration) offers a second lease of life to NTS. Long-term full and pilot cale experience in South Africa and Thailand have shown that contrary to a common view, a low tech N-removal from municipal and light industrial wastewater is a reality for a developing community The high treatment efficiency is ascribed to interplay of N-related processes complementing each other. The present FISH-based (Fluorescence In Situ Hybridization) approach to microbial community structure is a pioneering effort in the field of NTS. It establishes interrelationships between major N-removing groups (aerobic and anaerobic ammonia oxidizers (ANAMMOX), denitrifiers) within integrated systems and links them to the high treatment performance. Seasonally fluctuating presence of the ANAMMOX bacteria (0-2.5% of total bacterial numbers) in the NTS (free surface flow wetland) is reported for the first time. Their numbers correlate with metabolically dependent ammonia-oxidizers (2.0-3.0%) but not with stable overall Planctomycetes population (4.5-5.1%). As a result of the flexible microbial structure the robust low cost removal down to TN < 10 mg/L is routinely feasible at the loading rates ranging from 0.005 to 0.08 TN kg/m3/day.
Shipin
O
O
Environmental Engineering and Management Program, School of Environment, Resources and Management, Asian Institute of Technology, P.O. Box 4, Pathumthani, 12120, Thailand. oshipin@ait.ac.th
Koottatep
T
T
Khanh
N T T
NT
Polprasert
C
C
D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D001420:Bacteria, Aerobic / Q000502:physiology; D001421:Bacteria, Anaerobic / Q000502:physiology; D019149:Bioreactors; D004784:Environmental Monitoring; D017404:In Situ Hybridization, Fluorescence; D009573:Nitrites / Q000737:chemistry / Q000378:metabolism; D009584:Nitrogen / Q000302:isolation & purification*; D011157:Population Dynamics; D012621:Seasons; D012722:Sewage / Q000737:chemistry / Q000382:microbiology*; D014865:Waste Disposal, Fluid / Q000379:methods*; D018508:Water Purification / Q000379:methods*
D009573:Nitrites; D012722:Sewage; D000641:Ammonia; D009584:Nitrogen