A method for enhancing in situ bioremediation of a volume containing groundwater and a quantity of contaminant, the method comprising the steps of: quantifying the mass of the contaminant; and amending the volume by adding thereto a compound that provides a source of NO.sub.3.sup.−. The method is characterized in that the compound is added such that the mass of the NO.sub.3.sup.− source is provided at the ratio of about 1 mg NO.sub.3.sup.− per 0.21 mg contaminant. The contaminant can be BTEX or petroleum-related VOC.

A method for enhancing in situ bioremediation of a volume containing groundwater and a quantity of contaminant, the method comprising the steps of: quantifying the mass of the contaminant; and amending the volume by adding thereto a compound that provides a source of NO.sub.3.sup.−. The method is characterized in that the compound is added such that the mass of the NO.sub.3.sup.− source is provided at the ratio of about 1 mg NO.sub.3.sup.− per 0.21 mg contaminant. The contaminant can be BTEX or petroleum-related VOC.

The present disclosure provides an in-situ method for removing sulfates. The method comprises delivering at least one low molecular weight organic compound (LMWOC) to soil or groundwater to attain a concentration of the LMWOC of 750-3000 mg/L, such as 1000-2000 mg/L, or about 1500 mg/L, especially whereby sulfate is reduced to below 250 mg/L in the soil or groundwater. The method may further comprise contacting the soil or groundwater with an oxidizer, such as hydrogen peroxide, whereby the concentration of metals or metalloids is reduced in the soil or groundwater.

The present disclosure provides an in-situ method for removing sulfates. The method comprises delivering at least one low molecular weight organic compound (LMWOC) to soil or groundwater to attain a concentration of the LMWOC of 750-3000 mg/L, such as 1000-2000 mg/L, or about 1500 mg/L, especially whereby sulfate is reduced to below 250 mg/L in the soil or groundwater. The method may further comprise contacting the soil or groundwater with an oxidizer, such as hydrogen peroxide, whereby the concentration of metals or metalloids is reduced in the soil or groundwater.

Integrated methanogenic anaerobic reactor and membrane bioreactor, and method for eliminating organic matter and nitrogen in urban or industrial wastewater, preferably with COD concentrations between 150 and 5000 mg/L and where the eliminations of total nitrogen that occur are between 15 and 50 mg/L, at temperatures above 15° C. The wastewater treatment takes place thanks to three stages of treatment: methanogenic anaerobic stage, anoxic stage with biofilms and suspended biomass and aerobic filtration stage with biofilms and suspended biomass.

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.

A modular liquid waste treatment system is disclosed. In accordance with some embodiments, the system includes a central distribution unit and one or more treatment fins in flow communication therewith. The distribution unit may be configured to receive liquid waste from a given source and distribute that waste, at least in part, to one or more treatment fins. In turn, bacteria present in a given treatment fin treat the liquid waste, and the resultant treated liquid may drain from the fin to the surrounding environment. In some embodiments, a given treatment fin may include porous media providing a large surface area on which bacteria may grow to facilitate treatment. The system may be installed in and/or above the ground, and in some cases may be surrounded, at least in part, with treatment sand and/or other treatment media. The system may be used in aerobic and/or anaerobic processing of liquid waste.

A modular liquid waste treatment system is disclosed. In accordance with some embodiments, the system includes a central distribution unit and one or more treatment fins in flow communication therewith. The distribution unit may be configured to receive liquid waste from a given source and distribute that waste, at least in part, to one or more treatment fins. In turn, bacteria present in a given treatment fin treat the liquid waste, and the resultant treated liquid may drain from the fin to the surrounding environment. In some embodiments, a given treatment fin may include porous media providing a large surface area on which bacteria may grow to facilitate treatment. The system may be installed in and/or above the ground, and in some cases may be surrounded, at least in part, with treatment sand and/or other treatment media. The system may be used in aerobic and/or anaerobic processing of liquid waste.

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.

Systems and method for treating wastewater including a vessel having an inlet and an outlet, a pump in fluid communication with the outlet of the vessel, the pump configured to pump wastewater out of the vessel, a separator in fluid communication with the pump, the separator configured to separate grit from the wastewater, the separator having a first outlet for discharging a grit stream and a second outlet for discharging a wastewater stream, a grit washing system in fluid communication with a source of washing fluid and the first outlet of the separator, the grit washing system configured to wash and dewater grit from the grit stream, the grit washing system having an outlet for discharging a wash wastewater stream, and a return conduit configured to recycle the wastewater stream discharged from the separator to one of the inlet of the vessel and an inlet to the pump.