Medium Temperature Belt Dryer in Wisconsin to Produce Class A Biosolids from Anaerobic Digested Sludge containing High Strength Waste – Case Study

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).

Download Full-text

Planning Your Class A Biosolids Program: Design Considerations and Lessons Learned in Pierce County, Washington

Proceedings of the Water Environment Federation ◽

10.2175/193864717821495960 ◽

2017 ◽

Vol 2017 (1) ◽

pp. 905-910

Author(s):

Melissa Newell

Keyword(s):

Program Design ◽

Lessons Learned ◽

Design Considerations ◽

Class A ◽

Class A Biosolids

Download Full-text

Design Optimization of Explosion-Resistant System Consisting of Steel Slab and CFRP Frame

Materials ◽

10.3390/ma14102589 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2589

Author(s):

Jung J. Kim

Keyword(s):

Hybrid System ◽

Impact Load ◽

Load Condition ◽

High Strength ◽

Dynamic Responses ◽

Elastoplastic Behavior ◽

Reinforced Polymer ◽

Steel Slab ◽

Strength Material

This study presents an explosion-resistant hybrid system containing a steel slab and a carbon fiber-reinforced polymer (CFRP) frame. CFRP, which is a high-strength material, acts as an impact reflection part. Steel slab, which is a high-ductility material, plays a role as an impact energy absorption part. Based on the elastoplastic behavior of steel, a numerical model is proposed to simulate the dynamic responses of the hybrid system under the air pressure from an explosion. Based on this, a case study is conducted to analyze and identify the optimal design of the proposed hybrid system, which is subjected to an impact load condition. The observations from the case study show the optimal thicknesses of 8.2 and 7 mm for a steel slab and a ϕ100 mm CFRP pipe for the hybrid system, respectively. In addition, the ability of the proposed hybrid system to resist an uncertain explosion is demonstrated in the case study based on the reliability methodology.

Download Full-text