Studying the pre-treatment conditions for sludge digestion in vitro

Dissertant

Nasir, Muhammad Tahir

Thesis advisor

al-Wasiti, Asawer Abd al-Rasul
al-Mukhtar, Riyad Sadiq Muhammad

University

University of Technology

Faculty

-

Department

Department of Chemical Engineering

University Country

Iraq

Degree

Master

Degree Date

2011

English Abstract

-Sludge disposal is one of the most important problems in Al-Rustumiya wastewater treatment plant (WWTP).

Anaerobic digestion (AD) is a common treating process to limit the sludge accumulation.

AD is consequence of series metabolic interactions among various groups of microorganisms.

It occurs in three stages hydrolysis, acidogenesis and methanogenesis.

In the AD, biological hydrolysis is defined as rate limiting step.

So, four pre-treatment methods (ultrasonic, chemical, thermal, and thermo-chemical) are investigated in addition to blank test (which is without pre-treating) in order to find their effect on solubilization, biogas production and total volatile solid removal efficiency.

Two frequencies of ultrasonic wave were used (30 KHz and 50 KHz) during ultrasonic pretreatment.

Sodium hydroxide was added in different amounts to give three pH levels of (9, 10 and 11) in chemical pre-treating process.

The sludge was heated with two temperature value of 60 ℃ and 80 ℃ through thermal pre-treatment experiment.

Also, the sludge was treated thermo-chemically at 80 ℃ and pH (11) prior to anaerobic digestion and finally blank test (untreated sludge) is done to compare with other experiments.

The test was done under condition of 37 ℃ and pH (7) with 14 days of retention time.

All of above suggested pre-treatment methods improved the subsequent sludge fermentation comparing to untreated digestion (blank test).

The blank test resulted in total SCOD of (18.1 gm/l) in addition to (3309 ml) of biogas production.

The overall arrangement of digestion improvement efficiencies compared with blank test, depending on solubilization increasing percentage is shown below: 30 KHz (178.34%) > pH (11) + 80 ℃ (153.6%) > pH (11) (107.1%) > 50 KHz (103.7%) > 80℃ (82.37%) > pH (10) (80%) > 60 ℃ (62%) > pH (9) (58%)

Main Subjects

Chemistry

Topics

• Water treatment
• Sanitation
• Waste water
• Anaerobic treatment

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305071