Effect of an acidic and readily-biodegradable non-hazardous industrial process waste on refuse decomposition.
Non-hazardous industrial process wastes are receiving increased interest from landfill owners, especially with respect to bioreactor operation. These wastes could benefit bioreactors as they represent sources of liquid, nutrients, and/or substrate as well as revenue. However, landfill operators should exercise caution in accepting these wastes, as some could have detrimental effects on refuse decomposition. In this research, the use of laboratory-scale tests to evaluate the effect of one such waste on refuse decomposition is demonstrated. The waste evaluated, referred to as burnt sugar, is an acidic byproduct of corn-based polylactic acid production and represents a source of readily-biodegradable carbon. Lactic acid was the primary constituent of the BS at 0.73 g/g and the COD was measured at 1230 mg COD/g. Testing protocols were adapted to address the specific concerns surrounding the material. Abiotic dissolution tests conducted at mesophilic temperatures indicated that the majority of the waste dissolved into leachate recirculated over a layer of the waste within several days. Abiotic mixing tests suggested that the waste would acidify refuse to pH 6.41 at a loading of 21.9 g/dry kg refuse. However, in biologically active tests, the refuse was able to convert loadings as high as 196.7 g/dry kg refuse to methane. As the loadings increased toward and beyond this level, pronounced detrimental effects to the refuse ecosystem were observed, including a decrease in pH, accumulation of volatile fatty acids and COD, and lag in methane production. The results suggested that actively decomposing refuse has the potential to attenuate relatively high loading of a rapidly degradable but acidic substrate. Nonetheless, caution in the implementation of a field program to accept rapidly biodegradable acidic wastes is critical.
Sadri
Ahmad
A
Department of Environmental Services, City and County of Honolulu, 91-174 Hanua St., Kapolei, HI 96707, USA. asadri@honolulu.gov
Staley
Bryan F
BF
Barlaz
Morton A
MA
Xu
Fang
F
Hater
Gary R
GR
D000143:Acids / Q000737:chemistry*; D001673:Biodegradation, Environmental; D002241:Carbohydrates / Q000737:chemistry; D002244:Carbon / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007220:Industrial Waste; D019344:Lactic Acid / Q000737:chemistry; D008697:Methane / Q000737:chemistry; D012037:Refuse Disposal / Q000379:methods*; D013696:Temperature; D018505:Waste Management / Q000379:methods*; D014866:Waste Products
D000143:Acids; D002241:Carbohydrates; D007220:Industrial Waste; D014866:Waste Products; D019344:Lactic Acid; D002244:Carbon; D008697:Methane