Effects of enzyme addition on anaerobic digestion of cattle waste

Date

1995-05

Journal Title

Journal ISSN

Volume Title

Publisher

Texas Tech University

Abstract

Six 4 L capacity laboratory-scale reactors with 3 L working volume were used to study the effects of enzyme addition on anaerobic digestion of cattle waste. All the reactors were operated under similar conditions with identical level of organic loading (three percent volatile solids). One of the reactors was used as a control and the remaining five reactors were treated with five different levels of enzyme dosage. The different enzyme dosages used were 0.5, 1, 2, 5, and 10 times the suggested dosage by the manufacturer (1 gallon/18,000 gallons of waste water). Several parameters, COD, TOC, pH, total solids, and total volatile solids, were used to evaluate the effects of enzyme addition on the anaerobic digestion of cattle waste. Results from the statistical data analysis showed that there was a significant difference between the control and each test reactors with different enzyme dosages. The results also showed that there was no significant difference among the different dosages of enzyme added. There was 25% to 35% (average of 29%) more reduction in COD and 25% to 30% (average of 27%) more reduction in TOC in the test reactors compared to the control. Also, there was 16% to 28% (average of 22%) more reduction in total volatile solids and 9% to 20% (average of 14%) more reduction in total solids in the test reactors compared to the control. The conclusion is that an addition of the enzyme did enhance the anaerobic digestion of cattle waste. Further, it was concluded that there was no direct correlation between the different levels of enzyme dosage and the degree of increased anaerobic digestion.

Description

Keywords

Anaerobic bacteria, Cattle -- Manure

Citation