A waste treatment process utilizes a two-stage digestion process with a thermophilic digester, a heat exchanger, and a mesophilic digester. The pH of the thermophilic digestate is increased by removal of carbon dioxide with an air stripper, or by adding a pH increasing reagent upstream of the heat exchanger. The pH adjustment of the digestate protects the heat exchanger and downstream equipment and processes from struvite formation. A struvite reactor may be located in various locations downstream of the heat exchanger to produce a treated digestate or effluent that contains struvite, which can optionally be recovered for beneficial use.

Disclosed herein is a process for the treatment of wastewater for biosolids reduction and biogas (i.e. methane) generation where a wastewater is provided to a first reactor which is operated under anaerobic conditions, a hydraulic/solids retention time of from 0.1 to 1 day, a temperature of from 30 to 70° C. and a pH of from 6.5 to 10, with the effluent of the first reactor passing to a second reactor which is operated under anaerobic conditions, a hydraulic/solids retention time of from 3 to 10 days and a temperature of from 30 to 70° C. The process may further comprise feeding an effluent produced from the second reactor to a third reactor operated under anaerobic conditions, a hydraulic/solids retention time of from 3 to 20 days and a temperature of from 30 to 70° C.

A system and method for treatment of wastewater, in which the system includes a blackwater reactor configured to receive a stream of blackwater influent, to contain the blackwater therein during treatment of the blackwater, to facilitate recovery of methane and nutrient precipitates therefrom, and to output partially treated blackwater, and a greywater reactor configured to receive a stream of greywater influent and the partially treated blackwater output from the blackwater reactor, to contain the greywater and the partially treated blackwater therein during greywater treatment, and to output greywater treatment discharge. The process includes inputting a stream of blackwater into the blackwater reactor; treating the blackwater in the blackwater reactor with an anaerobic digestion process; controlling a pH level of the blackwater within the blackwater reactor; recovering nutrient precipitates from the blackwater reactor, optionally independent of chemical additives; and recovering methane from the blackwater reactor.

The disclosure relates to anaerobic digestion of liquid waste streams. In one embodiment, the system for treating liquid waste comprises: an acid forming chamber; a plug-flow methanic chamber downstream from the acid forming chamber; and a weir structure provided between the acid forming chamber and the methanic chamber.

The invention relates to a method for treating organic waste, in particular to a method for treating sludge from wastewater treatment plants, in order to produce power and/or hygienized organic matter, including a first step of mesophilic or thermophilic digestion (13) of at least one fraction of a stream of organic waste, and comprising the following steps: dehydrating (15) all of the digested and non-digested waste; aerated thermal hydrolysis (16) of the dehydrated waste, including an injection of an oxidizing agent in a quantity lower than the stoichiometric quantity for oxidizing organic matter, and setting to the required temperature by a heating means; and a second mesophilic or thermophilic digestion (17) of the stream of hydrolyzed waste.

A solid waste treatment method includes the steps of: degradation and sterilization via chlorination of the solid waste, stabilization of the solid waste and regeneration of biomass to reduce or eliminate solid waste. The solid waste treatment method may be utilized in agricultural, industrial or municipal settings.

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.

Sludge, for example primary sludge or waste activated sludge or both from a wastewater treatment plant, is pre-treated prior to anaerobic digestion. The pre-treatment includes an optional mechanical treatment to reduce the viscosity of the sludge and a biological hydrolysis treatment. The biological hydrolysis treatment may be performed in a series of reactors some of which are maintained at a temperature in the range of 50 to 70° C. The reactors provide a combined residence time in the range of 0.5 to 6 days. Optionally, measurements of the pH of the sludge during or after biological hydrolysis, or the production of biogas from a downstream anaerobic digester, may be considered in adjusting the temperature of one or more of the biological hydrolysis reactors.

Methods and systems are described for treating a fluid that includes a particulate fraction and a soluble fraction, such as wastewater fluid including biosolids. The treatment includes biochemically transforming solids in the particulate fraction of the fluid in a biochemical process while simultaneously subjecting the fluid to a vacuum pressure, and evaporating off at least a portion of the soluble fraction of the fluid and thereby thickening a remaining portion of the fluid. A residence time of the particulate fraction can be controlled to be at least 25% greater than a residence time of the soluble fraction, for example. A solids content of the particulate fraction can be controlled to be in a range of from 2% to 99%, for example.

A process for reducing the production of sludge by municipal or industrial wastewater purification plants, comprising a step of mesophilic or thermophilic anaerobic digestion (20), or anaerobic digestion combining these two operating modes, of a stream of sludge to be treated (1), and at least one biological solubilization anaerobic treatment step (30); the process comprises, upstream of the anaerobic digestion step, a step of dehydration (10) of the sludge to be treated, followed by a step of mixing (15) the dehydrated sludge with a recirculated fraction of sludge that is more liquid, originating from recycling of the digestion (20), and/or from the anaerobic treatment step (30), and/or centrates originating from a final dehydration (50) of the treated sludge, wherein the recirculation rate is chosen such that the mixture has a dryness suitable for digestion, this mixture then being directed towards the digestion.