The present invention relates to a hydrated crystalline form of 2-acrylamido-2-methylpropane sulfonic acid having a 2-theta powder X-ray diffraction diagram comprising peaks at 10.58°, 11.2°, 12.65°, 13.66°, 16.28°, 18.45°, 20°, 20.4°, 22.5°, 25.5°, 25.88°, 26.47°, 28.52°, 30.28°, 30.8°, 34.09°, 38.19°, 40.69°, 41.82°, 43.74°, 46.04° degrees (+/−0.1°).

The present invention also relates to a production method for this form of 2-acrylamido-2-methylpropane sulfonic acid and a preparation method for an aqueous solution A of a salt of this form of 2-acrylamido-2-methylpropane sulfonic acid, and the (co)polymer of this form of -acrylamido-2-methylpropane sulfonic acid.

The present invention discloses a process of disposal of tailings in piles stemming from the iron ore processing method, replacing dams, and comprising the steps of thickening the ultra-fine tailings, thickening the sandy tailings, mixing the tailings in the proportion of 80 to 90% by weight of sandy tailings and 10 to 20% by weight of ultra-fine tailings, addition of coagulant, addition of flocculant, filtering the mixture and piling the filtered tailings. Unlike traditional processes, this invention promotes an economically and technically feasible tailing disposal process that can be added to any conventional iron ore concentration plant without the need for any change in the process flowchart.

In a system and process, sludge from a wastewater treatment plant is treated in a high solids digester, optionally a mechanically mixed wet digester. Sludge (i.e. digestate) from the anaerobic digester is thickened or dewatered. Part of the thickened or dewatered digestate is thermally hydrolysed. The hydrolysed digestate may be, or may be further treated to produce, Class A biosolids. The hydrolysed digestate can be dewatered producing a liquid fraction that is recycled to the digester. Another part of the thickened or dewatered digestate is returned to the digester. The return of thickened or dewatered digestate to the digester allows for a smaller tank to be used (compared to a system without a recycle of thickened or dewatered digestate) while maintaining the same solids residence time (SRT) and volatile solids reduction (VSR). In some examples, the hydraulic residence time (HRT) of the digester is 10 days or less.

In a system and process, sludge from a wastewater treatment plant is treated in a high solids digester, optionally a mechanically mixed wet digester. Sludge (i.e. digestate) from the anaerobic digester is thickened or dewatered. Part of the thickened or dewatered digestate is thermally hydrolysed. The hydrolysed digestate may be, or may be further treated to produce, Class A biosolids. The hydrolysed digestate can be dewatered producing a liquid fraction that is recycled to the digester. Another part of the thickened or dewatered digestate is returned to the digester. The return of thickened or dewatered digestate to the digester allows for a smaller tank to be used (compared to a system without a recycle of thickened or dewatered digestate) while maintaining the same solids residence time (SRT) and volatile solids reduction (VSR). In some examples, the hydraulic residence time (HRT) of the digester is 10 days or less.

A sludge dehydration method includes a recovery process of recovering specific material as a dewatering aid from sludge generated in a sewage treatment process and a dewatering process of performing solid-liquid separation on sludge in which the dewatering aid recovered in the recovery process and dewatering target sludge are mixed.

A sludge dehydration method includes a recovery process of recovering specific material as a dewatering aid from sludge generated in a sewage treatment process and a dewatering process of performing solid-liquid separation on sludge in which the dewatering aid recovered in the recovery process and dewatering target sludge are mixed.

An apparatus for dewatering sludge comprises a tank having an internal space divided by a dividing wall into an intake chamber and an extract chamber, an intake pipe connected to the intake chamber by an intake valve, a discharge pipe connected to the extract chamber by a discharge valve, and a transfer pipe providing fluid communication between the intake chamber and the extract chamber. The transfer pipe has first opening near the bottom of the intake chamber, and a second opening near the top of the extract chamber. A pump selectively creates positive and negative pressure within the intake chamber. A screen is positioned within the extract chamber between the second opening of the transfer pipe and the discharge pipe.

An apparatus for dewatering sludge comprises a tank having an internal space divided by a dividing wall into an intake chamber and an extract chamber, an intake pipe connected to the intake chamber by an intake valve, a discharge pipe connected to the extract chamber by a discharge valve, and a transfer pipe providing fluid communication between the intake chamber and the extract chamber. The transfer pipe has first opening near the bottom of the intake chamber, and a second opening near the top of the extract chamber. A pump selectively creates positive and negative pressure within the intake chamber. A screen is positioned within the extract chamber between the second opening of the transfer pipe and the discharge pipe.

Disclosed are filter aids for use in industrial processes such as metal ore beneficiation dewatering and filtering processes, paper and pulp dewatering processes and sludge dewatering in municipal waste treatment. The filter aid provides increased filtering efficiency, and reduced filter cake moisture levels.

Disclosed are filter aids for use in industrial processes such as metal ore beneficiation dewatering and filtering processes, paper and pulp dewatering processes and sludge dewatering in municipal waste treatment. The filter aid provides increased filtering efficiency, and reduced filter cake moisture levels.