Long-term monitoring strategies for paper sludge landfill covers

This paper discusses the long-term monitoring strategies and field performance of paper mill sludge landfill covers. In some cases, paper sludge covers can be marginal in terms of hydraulic conductivity or slope stability, thus, a monitoring strategy should be specified to evaluate performance compliance. The unique geotechnical behavior of paper sludges includes large settlement strains or large reductions in void ratio which induce decreases in hydraulic conductivity and increases in undrained shear strength (which improve slope stability). For example, the case histories presented herein showed decreases in hydraulic conductivity about one half an order of magnitude or greater one year after construction. Furthermore, the final settlement strains for the paper sludge covers presented in this study varied from about 18% to 35%. This type of behavior is not typical of compacted clays. The recommended long-term monitoring strategy is centered around settlement, hydraulic conductivity and undrained shear strength relative to slope stability. Also, basic index properties (water content, organic content and specific gravity) can provide additional information about the general state of the paper sludge hydraulic barrier in terms of consolidation and organic decomposition.

• 1 INTRODUCTION

• 2 GEOTECHNICAL PROPERTIES

• 3 LONG-TERM MONITORING

• 4 SUMMARY AND CONCLUSIONS

• 5 REFERENCES