Relatively greater capillarity material layers and relatively lesser capillarity material layers are provided. These layers can be used to promote capillary wetting in capillary wetting zones to promote prolonged periods of water retention. Carbon sources present in the capillary wetting zones may exhibit prolonged use provided by limited drying and wetting cycles experienced in the capillary wetting zones. Carbon sources positioned between saturated layers may exhibit prolonged use provided by anoxic conditions created by upper and lower water seals of the saturated layers. Capillarity layers can be employed in infiltration systems handling water, such as residential wastewater.

The present invention relates to a coagulant composition comprising a coagulant and a carbon source compound, wherein the coagulant is selected from the group iron and aluminium salts, or any combination thereof. The carbon source includes methanol, ethanol or glycol. The present invention further relates to a method of treating wastewater, e.g. containing nitrogen and/or phosphate, including providing the coagulant composition to wastewater before, during and/or after a biological treatment step, and the use of the coagulant composition in wastewater treatment.

The present invention relates to a coagulant composition comprising a coagulant and a carbon source compound, wherein the coagulant is selected from the group iron and aluminium salts, or any combination thereof. The carbon source includes methanol, ethanol or glycol. The present invention further relates to a method of treating wastewater, e.g. containing nitrogen and/or phosphate, including providing the coagulant composition to wastewater before, during and/or after a biological treatment step, and the use of the coagulant composition in wastewater treatment.

Carbon sources, such as food-grade oil, present in or above infiltration fields or other areas of water leaching systems, are employed, the water leaching systems having one or more layers. Carbon sources, such as food-grade oil, whether in aerobic or anaerobic conditions or saturated and unsaturated conditions may provide denotification of water interfacing with the oil or other carbon source.

Treatment of wastewater containing contaminants is provided. More specifically, treating wastewater through capture and recirculation of percolated fluid effluent through and from one or more infiltration field systems is provided.

A system for treating nitrate nitrogen sewage by autotrophic denitrification subsurface flow constructed wetland and a method thereof. The system includes a wetland pool body, a wetland substrate, a water distribution device, a water outlet device, and plants. The wetland substrate is filled in the wetland pool body. The wetland substrate includes pyrite, volcanic rock, and biochar. The water distribution device is located at the top of the wetland pool body to distribute water into the wetland pool body, and the water outlet device is located at the bottom of the wetland pool body to collect treated sewage. The plant is planted in the wetland substrate. The dissolved oxygen concentration of the system for treating nitrate nitrogen sewage by autotrophic denitrification subsurface flow constructed wetland is maintained at 1.2?2.8 mg/L.

The present invention relates to a method for decreasing the contents of metals, metalloids, nitrate and nitrite, respectively, in raw water flowing through a basin (1), whereby water containing either oxygen, oxygen-releasing substances, naturally occurring micro-organisms and/or substrates therefore is intermittently introduced to the basin (1) through horizontally arranged infiltration/extraction means (2) above and below the injection pipes of raw water, and by alternating the withdrawal and infiltration of conditioned water between the horizontal means so that essentially a vertical flow of water is created between these means, thereby creating a reaction zone for purification of raw water before it reaches the central extraction well. The water to be purified is fed into the basin by horizontally arranged feeding pipes (5) and the extraction of purified water from said at least one extraction well (3) is such that a substantially negative pressure is created around said at least one extraction well (3). The invention relates also to an apparatus for carrying out the method.

A water treatment system receives nitrate-rich water at pressure from a source and filters that water through an upflow configured biological reactor. Upflow configuration fluidizes a bacterial population within the reactor without requiring mechanical agitation. Outflow of the biological reactor is provided as input to a recirculation loop that at least partially recirculates water back into the reactor, thereby self-blending with influent water provided as inflow to the reactor. The recirculation loop also serves as a dosing location for controlling pH, external carbon availability, and the like. Dosing within the recirculation loop ensures that the environment within the reaction volume remains stable and additives are efficiently perfused. Outflow of the recirculation loop is provided as inflow to downflow configured post filters. Outflow of the post filters can be provided as potable or non-potable denitrified water.

A rainwater garden including: a bioretention area; a rainwater collection area; and a first perforated drainage pipe. The bioretention area includes, from bottom up, a gravel layer, a transition layer, a chalcopyrite substrate layer, a biochar substrate layer, a planting layer, a cover layer, and a water storage layer. The first perforated drainage pipe is disposed in the gravel layer. The first perforated drainage pipe includes an outlet end extending to connect to the rainwater collection area; and the outlet end is flush with a top surface of the chalcopyrite substrate layer.