ABSTRACT
<p><b>OBJECTIVE</b>To explore the process of refuse decomposition in hybrid bioreactor landfill.</p><p><b>METHODS</b>The bioreactor landfill was operated in sequencing of facultative-anaerobic and aerobic conditions with leachate recirculation, pH, COD, and ammonia in the leachate and pH, biodegradable organic matter (BDM), and cation exchange capacity (CEC) in refuse were detected.</p><p><b>RESULTS</b>CEC increased gradually with the degradation of refuse, which was negatively correlated with BDM. COD and ammonia in the leachate was declined to 399.2 mg L(-1) and 20.6 mg N L(-1), respectively, during the 357-day operation. The respective concentrations of ammonia and COD were below the second and the third levels of current discharge standards in China.</p><p><b>CONCLUSION</b>The refuse is relatively stable at the end of hybrid bioreactor landfill operation. Most of the readily biodegradable organic matter is mineralized in the initial phase of refuse degradation, whereas the hard-biodegradable organic matter is mainly humidified in the maturity phase of refuse degradation.</p>
Subject(s)
Ammonia , Biodegradation, Environmental , Bioreactors , Cations , Hydrogen-Ion Concentration , Methane , Organic Chemicals , Oxygen , Regression Analysis , Time Factors , Waste Disposal, Fluid , Water Pollutants, ChemicalABSTRACT
<p><b>OBJECTIVE</b>To examine the effect of hydraulic residence time (HRT) on the performance and stability, to treat dilute wastewater at different operational temperatures in a carrier anaerobic baffled reactor (CABR), and hence to gain a deeper insight into microbial responses to hydraulic shocks on the base of the relationships among macroscopic performance, catabolic intermediate, and microcosmic alternation.</p><p><b>METHODS</b>COD, VFAs, and microbial activity were detected with constant feed strength (300 mg/L) at different HRTs (9-18 h) and temperatures (10 degrees C-28 degrees C) in a CABR.</p><p><b>RESULTS</b>The removal efficiencies declined with the decreases of HRTs and temperatures. However, the COD removal load was still higher at short HRT than at long HRT. Devastating reactor performance happened at temperature of 10 degrees C and at HRT of 9 h. HRTs had effect on the VFAs in the reactor slightly both at high and low temperatures, but the reasons differed from each other. Microbial activity was sensitive to indicate changes of environmental and operational parameters in the reactor.</p><p><b>CONCLUSION</b>The CABR offers to certain extent an application to treat dilute wastewater under a hydraulic-shock at temperatures from 10 degrees C to 28 degrees C.</p>