Disclosed is a method for thickening or dehydrating sludge, which includes at least: a) a step of adding flocculants to the sludge to be treated; b) a step of flocculation by agitation of the sludge with the flocculants thus added in order to form a mixture of flocks and an aqueous solution; c) a step of mechanical separation of the flocks and the aqueous solution formed during the preceding step; d) a step of recovering the aqueous solution and the flocks that make up a treated sludge; wherein: the added flocculants are made up of at least one cationic starch (S) and at least one cationic polyacrylamide (P); the cationic starch or starches (S) including a fixed weight percentage of nitrogen of at least 2%; and the weight ratio (R) w.sub.s/(w.sub.s+w.sub.p), expressed as solids, is included between 0.6 and 0.99.

In an embodiment, a circuit includes: a transformer defining an inductive footprint within a first layer; a grounded shield bounded by the inductive footprint within a second layer separate from the first layer; and a circuit component bounded by the inductive footprint within a third layer separate from the second layer, wherein: the circuit component is coupled with the transformer through the second layer, and the third layer is separated from the first layer by the second layer.

Methods to improve dewatering in industrial and municipal sludges are described. One method involves admixing sludge from a papermaking process and modified cellulose to provide modified sludge with the modified cellulose present in an effective amount to improve dewatering in the treated sludge, such as in allowing use of reduced amounts of coagulant and/or reducing dewatering times, increased dewatered volumes, and reduced sludge product moisture contents, and the like. The dewatered sludge may be formed into a dried particulate, and may be used as filler or other component of concrete, rubber, asphalt, plastics, resin-wood composite products, and other composite products.

Powder blends are described comprising blends of particulate water soluble high molecular weight polymer flocculants. The polymer flocculants can include polyethylene oxide, polyacrylamide, copolymers thereof and combinations thereof. The powder blends allows the use of fine powders while reducing potential air quality and safety issues. The powder blends can be used for waste water purification, fiber dewatering, and the like. The powder blends can be diluted by a water dilution flow prior to entering a waste water stream.

The present invention relates to a process for the purification of water, wherein a surface-reacted natural calcium carbonate is brought into contact with the water to be purified, the surface-reacted natural calcium carbonate being the reaction product of a natural calcium carbonate with an acid and carbon dioxide, which is formed in situ by the acid treatment and/or supplied externally.

The present disclosure provides compositions and methods for treating volatile fatty acids and bacteria capable of producing volatile fatty acids. The compositions can convert acid-producing bacteria environments to nitrate-reducing bacteria environments. The compositions and methods can lower the amount of acid-producing bacteria present in the environment and thereby reduce the amount of volatile fatty acids present in the environment. The control agent may also inhibit the growth of acid-producing bacteria and volatile fatty acid concentrations. The compositions and methods can be used with any aqueous industrial system.

A system and method for monitoring process water treated with a biocide is provided. The system includes a biocide feeding unit and a dissolved oxygen sensor. The dissolved oxygen sensor works in two modes, a biocide feeding mode and a background mode, and alerts an operator when the dissolved oxygen value indicates a fault in the system. A drop in dissolved oxygen during feeding can indicate faulty production of biocide or biocide degradation, both of which can lead to unwanted disinfection by-products.

A biofilm process is disclosed for treating wastewater containing readily biodegradable dissolved organic matter GP (measured as chemical oxygen demand or COD) and producing surplus biomass from the biofilm process that includes an enhanced polyhydroxyalkanoate (PHA) content. The process comprises directing a wastewater influent containing the readily biodegradable COD (RBCOD) into a biofilm unit process. The PHA content of surplus biomass is enhanced by controlling for a decreased biofilm process specific organic loading rate in combination with controlling phosphorus loading rates relative to the process RBCOD loading rates: (1) controlling the wastewater influent phosphorus loading rate to the biofilm unit process includes maintaining an average RBCOD/P ratio of the influent that is between 200 and 800 g/g; (2) decreasing the process specific organic loading rate includes producing a biofilm unit process effluent having readily separable mixed liquor volatile suspended solids (RS-MLVSS); and (3) separating a portion of the RS-MLVSS from the biofilm unit process effluent and recycling at least a portion of the separated RS-MLVSS back to the biofilm unit process. The combination of the RBCOD/P control and specific loading rate control maintains, on average, the surplus biomass with a PHA content that is greater than 30% gPHA/g VSS.

A method for treating effluent provides the effluent as an input to an apparatus having a vortex diode with aeration. The apparatus induces a cavitation assisted with aeration for the high rates of ammoniacal nitrogen in an orifice and the vortex diode with or without inserts/stabilizers to generate radicals, which reduce ammoniacal nitrogen of wastewater effectively during effluent treatments.

An external micro-interface papermaking wastewater treatment system and a wastewater treatment method are proposed. The wastewater treatment system includes a grating water collection tank, a first coagulation sedimentation tank, an inclined screen and a second coagulation sedimentation tank which are connected in sequence, a heat exchanger, a preheater and a wet oxidation reactor, wherein the heat exchanger is provided with a first inlet, a first outlet, a second inlet and a second outlet. A feed inlet is disposed on a side wall of the wet oxidation reactor, an oxidation water outlet is disposed on a top of the wet oxidation reactor, the feed inlet is connected with a micro-interface generator for dispersing and breaking gas into gas bubbles, a liquid phase inlet and a gas phase inlet are disposed on the micro-interface generator, and the gas phase inlet is connected with an air compressor.