An arrangement and a method for controlling a dewatering process including measuring values representing operating parameters of the gravitational sedimentation device and using the values as input values for a predictive multivariable model for predicting an operating state of the gravitational sedimentation device. The disclosure further relates to obtaining reference values for the operating parameters, determining at least one predicted output for an operating parameter of the gravitational sedimentation device, and comparing the predicted output to at the reference values to determine control values that will affect changes in operation of the gravitational sedimentation device.

A flocculation and sedimentation apparatus has: sedimentation tank that causes flocs in raw water to be sedimented and separated; sludge concentration tank that is surrounded by sedimentation tank and that collects and concentrates the flocs; and raw water supply mechanism having center line that passes through sludge concentration tank, wherein raw water supply mechanism rotates about center line and supplies the raw water to sedimentation tank. Raw water supply mechanism includes: raw water introducing portion that is located on center line and to which the raw water is introduced, raw water supply port that is open at a lower portion of an inner space of sedimentation tank and that supplies the raw water to sedimentation tank, and pipe portion that communicates both with raw water introducing portion and with raw water supply port and that extends above sludge concentration tank in a direction away from center line.

A flocculation and sedimentation apparatus has: sedimentation tank that causes flocs in raw water to be sedimented and separated; sludge concentration tank that is surrounded by sedimentation tank and that collects and concentrates the flocs; and raw water supply mechanism having center line that passes through sludge concentration tank, wherein raw water supply mechanism rotates about center line and supplies the raw water to sedimentation tank. Raw water supply mechanism includes: raw water introducing portion that is located on center line and to which the raw water is introduced, raw water supply port that is open at a lower portion of an inner space of sedimentation tank and that supplies the raw water to sedimentation tank, and pipe portion that communicates both with raw water introducing portion and with raw water supply port and that extends above sludge concentration tank in a direction away from center line.

The present invention relates to a waste water treatment process and system for treatment of waste water utilizing a diatomite treatment agent containing about 98 to 99.9% by weight of diatomite particles, wherein the diatomite particles comprise unbalanced surface charges and is substantially free of counter ions being electrostatically coupled to the unbalanced surface charges, and wherein the diatomite treatment agent is obtained from the disclosed pre-treatment process. This diatomite treatment agent has posed several advantages in a waste water treatment process, particularly acting as a biomass carrier, physical coagulant and adsorbent in a system for treatment of waste water, the system comprising a specially designed clarifier.

The present invention relates to a waste water treatment process and system for treatment of waste water utilizing a diatomite treatment agent containing about 98 to 99.9% by weight of diatomite particles, wherein the diatomite particles comprise unbalanced surface charges and is substantially free of counter ions being electrostatically coupled to the unbalanced surface charges, and wherein the diatomite treatment agent is obtained from the disclosed pre-treatment process. This diatomite treatment agent has posed several advantages in a waste water treatment process, particularly acting as a biomass carrier, physical coagulant and adsorbent in a system for treatment of waste water, the system comprising a specially designed clarifier.

A process for producing alumina trihydrate includes a digestion step, a separation step, and a precipitation step the separation step including: b1) pretreating a slurry from the digestion step by adding a flocculant to said slurry and mixing the flocculant and the slurry, b2) settling the resulting flocculated slurry in a gravity settler vessel, b3) determining a measured value representative of the concentration of solid particles in the resulting clarified liquor, b4) comparing the measured value with a predetermined threshold, b5) feeding said clarified liquor directly to the precipitation step, while the measured value is less than said predetermined threshold, and b6) redirecting said clarified liquor to the pre-treatment step b1), when the measured value is more than said predetermined threshold. An installation may be configured for operating said process.

A process for producing alumina trihydrate includes a digestion step, a separation step, and a precipitation step the separation step including: b1) pretreating a slurry from the digestion step by adding a flocculant to said slurry and mixing the flocculant and the slurry, b2) settling the resulting flocculated slurry in a gravity settler vessel, b3) determining a measured value representative of the concentration of solid particles in the resulting clarified liquor, b4) comparing the measured value with a predetermined threshold, b5) feeding said clarified liquor directly to the precipitation step, while the measured value is less than said predetermined threshold, and b6) redirecting said clarified liquor to the pre-treatment step b1), when the measured value is more than said predetermined threshold. An installation may be configured for operating said process.

An apparatus for diffusing wastewater into a clarifier is disclosed. The apparatus has a rotationally symmetric hollow body having a plurality of flow distributors positioned about a perimeter of the rotationally symmetric hollow body and a baffle extending around a bottom end portion of the rotationally symmetric hollow body. The apparatus is dimensioned to fit within an influent well of the clarifier and be connectable to the clarifier on a top end portion of the rotationally symmetric hollow body. A wastewater treatment system including a clarifier and the apparatus is disclosed. A method of retrofitting a circular clarifier by providing the apparatus is also disclosed.

A method for separating solids from liquids is disclosed. A double-roller system is provided. A process fluid is provided to the double-roller system. The process fluid comprises a suspended solid and a process liquid. The suspended solid comprises non-fibrous solid particles. A portion of the process fluid is compressed through the double-roller system to produce a compressed portion of the suspended solid. A product stream and a dilute fluid stream are separated. The product stream comprises a compressed portion of the suspended solid and a first portion of the process liquid. The dilute fluid stream comprises a second portion of the suspended solid and a second portion of the process liquid.

A scum removal system for use with a wastewater treatment clarification tank containing wastewater is provided and includes a debris intake conduit, a debris discharge conduit, and a pump article. The pump article is configured to be in flow communication with the debris intake conduit and the debris discharge conduit, wherein the pump article and debris intake conduit are configured to generate a suction within the debris intake conduit and wherein the debris intake conduit is configured to be located proximate the wastewater. Additionally, the debris intake conduit is sloped downwardly at a debris intake conduit angle , and the second discharge conduit is sloped downwardly at a debris discharge conduit angle .