Influent COD Concentration Research Articles

回転円板法による有機物除去に及ぼす負荷変動の影響

Laboratory scale rotating biological contactors were operated with synthetic wastewater to study the effects of the daily fluctuation of hydraulic and/or organic loadings as observed in wastewater treatment plants for small communities on the removal of organic substrates. The following results were obtained. 1) Daily average effluent COD values observed in operations with varying inflow rate and strength of wastewater (variable loading) were higher than those of constant loading (no daily fluctuation of inflow rate nor strength of wastewater) with equivalent daily BOD and hydraulic loadings. 2) Little fluctuation in effluent COD was noted by the fluctuation of influent COD concentration under smaller constant flow rate, whereas the fluctuation increased with the increase in hydraulic loading. 3) Attached biomass observed in operations with variable loadings were smaller than those observed in constant loading operations with equivalent daily BOD and hydraulic loadings to high loading period of variable loading. This fact, i.e. the shortage of attached biomass, seemed to result in the higher effluent COD values during high loading period in variable loading operations and, as a consequence, the higher daily average effluent COD values.

Aerobic Bio-Treatment of a High-Strength Leachate

The potential adverse environmental effects of landfill leachates have been well documented and their control and treatment is currently the subject of considerable research. This study investigated aerobic biological treatment of a high-strength leachate, without any prior removal of heavy metals or toxic substances. Using high MLVSS concentrations (8000 ppm-16,000 ppm), along with the combination of air and mechanical mixing, to control foaming, digester stability was achieved with sludge ages ranging from 10 days-60 days. With influent COD concentrations between 44,000 ppm and 52,000 ppm, settled effluent COD removal efficiencies greater than 97% were obtained. Increasing the sludge age from 10 days to 20 days, significantly improved the quality of the settled effluent. In addition, the leachate contained such heavy metals as aluminum, cadmium, chromium, copper, lead, nickel, and zinc. Zinc exhibited the highest influent concentration at greater than 200 ppm.

Biological and Physical-Chemical Treatment of Leachate From Sanitary Landfills

Abstract This research was undertaken to study the treatability of leachate from sanitary landfills using aerobic biological processes and physical-chemical treatment methods. Treatment for polishing effluents from aerobic biological systems was also evaluated. To ensure uniform characteristics throughout these treatability studies, leachate was collected from a laboratory lysimeter in the Water Resources Laboratory at the University of Waterloo. The effectiveness of aerobic biological treatment was investigated using both batch and continuous flow bench-scale reactors for COD concentrations in the range of 8000 to 12000 mg/l. Removal of COD efficiencies greater than 95% was achieved. The mean hydraulic residence time was of the order of 10 days and mixed liquor suspended solids ranged from 2500 to 5500 mg/1. Phosphorus was found to be deficient and supplements were required to promote sludge growth. Design parameters were developed to model process performance and unit costs were estimated for a range of flow rates and influent COD concentrations. Physical-chemical treatment studies were performed using a conventional jar test apparatus. Lime and alum were found to be ineffective in treating raw leachate. Lime, used in conjunction with polyelectrolyte coagulant aids, was effective for removal of suspended solids from the effluents of the biological reactor. Activated carbon adsorption was evaluated as a tertiary process for polishing biological effluents and was shown to be effective for removing residual concentrations of COD, colour, suspended solids and trace concentrations of metallic ions.