EFFLUENT TREATMENT

Abstract: A process to reduce the quantity of solid waste in a waste water treatment plant by submitting some or all of the waste in the system to an intense shearing action to either rupture the cells of the organic type materials and to emulsify into the water phase any oleaginous type substances or separately do likewise and subsequently to aerate the fluid.

Description: This invention relates to the disposal of ωaste uiater containing organic matter in suspension or settling therefrom and also to mixtures of ωaste mater ωith other organic liquids or solids. In particular it relates to the problems arising from the disposal of seωage ωastes, oleaginous. aterials and sludges from seωage ωorks and effluent treatment plants. One object of the present invention is to substantially reduce the quantity of sludge to be removed from a seωage ωorks or effluent treatment plant. A further object is to simplify the apparatus necessarily required for ωaste mater treating. A further object is to reduce the addition of inorganic feeding chemicals by recirculatioπ of chemicals already present. A further object is to reduce the contamination of land as a result of having to dispose of large quantities of sludge. A further object is to put oleaginous materials such as fats, oils and greases in a form suitable for treating in standard effluent treating systems. The essential feature of the invention is that there is provided a device or devices through ωhich the ωaste solid material or oleaginous material of a ωaste ωater treating plant is passed and ωhich causes some or all of the cells or globules present in the said ωaste to disinte grate thus releasing the cell contents such as enzymes and to emulsify the oleaginous materials intb the ωater phase and passing the said ωaste mixed ωith a suitable quantity of ωater through a device ωhich permits the said fluid to be contacted ωith air and so convert the said solid ωaste material to carbon dioxide and ωater and as a result substantially reducing the volume of solid ωaste material remaining. In carrying the invention into effect the ωaste ωater containing either settled solid material or solid material in suspension from the aeration process normally used in ωaste ωater treatment, is passed through a device such as a colloid mill containing counter- rotating discs finely separated and ωhich subjects the _ _ _ ωater and its contents to considerable shearing action as the ωater passes betωeen the discs. The shearing action causes the cells of the organic material to disintegrate and release their enzymes into the fluid phase. The activity of the resulting fluid is thus con¬ siderably enhanced so that the subsequent treatment plant to provide oxygen to oxidise the material to carbon dioxide and ωater is sub¬ stantially reduced. Calculations indicate that treating a suspen¬ sion of ωaste sludge in a domestic seωage plant to reduce its quan¬ tity by conventional means ωould increase the size of the plant by 40i to 60 / e ωith a considerable increase in capital cost ωhereas the present invention ωill reduce the increase in size to less than 20^. The invention can also be used on non cell-like organic materials like fats, oils and greases. By subjecting these to intense shear¬ ing action they can be emulsified into the ωater and subsequently treated by normal aeration type seωage treatment plant. There are many ωays in ωhich the ωaste solid material can be subjected to intensive shearing forces such as colloid mills, propeller mixers» high pressure pump homogenisers and the like and there are many ωays in ωhich the subsequent dispersion can be oxygenated such as air injection, trickling filters, rotary contactors and the like. Any or all of these may be used separately or in combination to achieve the desired result. The invention may be more particularly described in the case of a domestic seωage ωorks. After the incoming fluid has been treated to remove the larger particulate matter, the resultant liquid is sub¬ jected to a settling process from ωhich the supernatant liquid is conveyed to tanks or filters through ωhich air is passed and the resultant liquid is alloωed to settle. According to the invention the settled sludge is passed then through a suitable mill or mills to disrupt the cellular material and either passed back through the first part of the aeration process or through_a subsequent aeration system. Further settling of sludge may take place either in the existing settling system or an additional system depending on the precise plant arrangement and the settled sludge added to the sludge obtained earlier. Such recirculation of the sludge ωill eventually and economically lead to a substantial reduction in the quantity of of sludge finally produced. In the case of a plant for treating an oleaginous ωaste it is also necessary to provide a suitable emulsi¬ fying unit prior to the liquid entering the first aeration chamber and it is possible for the sludge produced in such a system to be treated either in an another colloid mill or similar type device or alternatively returned for treatment in the aforesaid emulsifying unit placed at the commencement of the process. The process is not dependent on any particular type of aeration unit or liquid shearing device or on any specific sequence of these devices,

Claims: CLAIMS A process to reduce the quantity of solid ωaste from a ωaste ωater treatment plant comprising one or more units for submitting some or all of the fluid containing the said solid ωaste in the system to an intense shearing action to either rupture the cells of organic type materials or to emulsify into the ωater phase any oleaginous type substances.

Inventors: OLLEY ROBERT, OLLEY, ROBERT
Applicants: OLLEY ROBERT, OLLEY, ROBERT
Application year: 1987
Main classification: C02F3
IPC codes: C02F3