Lime sludge, an inert material mostly composed of calcium carbonate, is the result of softening hard water before distribution as drinking water. A large city such as Des Moines, Iowa, produces about 32 000 tons of lime sludge (dry-weight basis) annually. This is about half of the lime sludge produced in Iowa per year in eight different cities, and these cities currently have 371 800 tons (dry-...

Pollutants in dye wastewater significantly vary due to the large number of dyes and other chemical compounds used in dyeing processes. The major compounds in dye wastewater are desizing and scouring agents, bleaches, reducing agents, detergents and wetting agents, finishing agents, organic acids and dyes, and fluorescent brighteners1). Physical, chemical and biological methods have been applied...

Ultrasonic technology is a promising tool for washing oily sludge to recover oil. In this study, the influence of ultrasonic conditions on the removal of different oil components from oily sludge was investigated to optimize ultrasonic washing technology. Among the three frequencies (25, 50 and 100 kHz) applied, ultrasonic washing at 25 kHz exhibited the best performance in terms of oil extract...

Biosolids are solid, semi-solid, or liquid materials resulting from the treatment of domestic sewage sludge. The term “biosolids” was introduced by the wastewater treatment industry in the early 1990’s and has been adopted by the United States Environmental Protection Agency (U.S. EPA) to distinguish high quality, treated sewage sludge from raw sewage sludge and from sewage sludge containing la...

The practical application of the Fenton-based treatment method for organic compounds-contaminated water purification is limited mainly because of the large amount of ferric sludge formed during the treatment, where ferrous iron (Fe(II)) is used as the activator of the hydrogen peroxide oxidation processes. Reuse of ferric sludge collected from clarifiers to substitute Fe(II) salts allows reduci...

An innovative and energy efficient sludge dewatering technology has been developed. The technology, impulse drying, involves briefly contacting the sludge under pressure with a heated surface. A unique feature of impulse drying is that the majority of moisture removal occurs as lipid water. A pilotand laboratory-scale demonstration was performed on low ash primary paper mill sludge. The pilot-s...

There is a major concern among scientists over the elevated levels of arsenic (As) in drinking water in Bangladesh and some parts of India. Investigating the release of As from water filter sludge in soil and its uptake by plants may provide information about the management of As contaminated filter sludge. In this macrocosm study, iron based sludge containing granular ferric hydroxide (GFH) wa...

The conventional sludge disposal options include landfill, application to farmland and forestry and incineration. However, since in the last decade sewage sludge and industrial sludge are being generated in increasing amounts due to the rapid urbanization and industrialization, a growing interest has been devoted in developing cost effective and renewable disposal alternatives. Among them, the ...

A greenhouse experiment was conducted to investigate the effect of sludge application on growth rate of three leafy vegetable spinach, celery and lettuce. Treatment design in control and 0.7 mg/kg dry weight of soil. Results showed that sludge was highly effective in celery growth compare to spinach and lettuce and increased dry and fresh weight of celery significantly. Photosynthesis rate impr...

Background & Aims of the Study: Industrial wastewater sludges must be disposed in a safe way because they have hazardous effects on the human and environment. The aim of this study is to investigate the physicochemical characteristics and disposal options of sludges from oil-water separator (OWS) and dissolved air flotation (DAF) clarifier of a Refinery wastewater treatment plant. Material...