An apparatus for recovering nutrients or water from digestate comprises one or more solid-liquid separation units, an ammonia stripping device, and a gas scrubbing unit. In a process, digestate is separated into a solids portion and a liquid portion. Ammonia is stripped from the liquid portion and converted into an ammonium salt solution which may be sold or used as, or blended with, a fertilizer product. Optionally, at least part of the remaining liquid portion may be concentrated to produce brine. The brine is mixed with the solids portion. The mixture may be dried and used as, or blended with, a fertilizer product. Optionally, a least part of the remaining liquid portion may be re-used as dilution water in a digester. A solids portion of the digestate, and one or both of an ammonium salt solution and a brine, may be used as fertilizer without thermal drying.

Phagotrophic algae are used in connection with aerobic or anaerobic digestion of solids, especially waste activated sludge (WAS), to more efficiently digest solids and to meet, over a shorter period of time, volatile solids standards and specific oxygen uptake rate requirements as well as pathogen reduction requirements.

The present invention discloses a method of utilizing refuses in urban and rural areas. The method includes a refuses collection step, a refuse distributing step, a primary magnetic separation step, a primary crushing step, a primary elutriation and floatation step, a uniform cutting step, an acidification and anaerobic treatment step, a selection and separation step, a buffering and adjusting step, an additional anaerobic treatment step and a sludge sedimentation and concentration step. The present invention can make the anaerobic treatment method continuatively dispose the refuses, thereby thoroughly solving the problem that non-anaerobic refuses such as waste plastics, water fiber etc. can not be recycled and completely recycling resources in the refuses.

The invention relates to a method and an arrangement for wastewater treatment, in which at least portions of the sewage sludge contained in the wastewater (0) are subjected to a hydrolysis (8). The hydrolysis (8) is carried out as a thermal hydrolysis. After the hydrolysis step (8), a drying process is (19) carried out. The drying process (19) is a process operating with positive pressure in the steam region. At least parts of the steam resulting from the drying process (19), which operates with positive pressure, are fed (20) to the portions of the sewage sludge in the thermal hydrolysis (8).

This invention is a method for the processing of organic materials or organic wastes in a cost-effective and environmentally sound manner. The invention works both in the anaerobic or aerobic state. Processing organic material is accomplished by forcing the flow of gas through a pile of material, containing some organic matter, with liquids and gravity. The movement of gas and liquids through the pile results in very large increases in microorganism populations, accelerated evolution of the microorganisms, and corresponding increases in the processing provided organic materials.

The present invention discloses a composite biogenic flocculant for enhancing flocculation and dewaterability of chemically enhanced primary treatment (CEPT) sludge. The present invention also discloses method of conditioning CEPT sludge using the composite biogenic flocculant.

Methods for capture of biogas from a wastewater system are disclosed herein. The methods may include the step of collecting biogas within a collector chamber of a biogas collector formed at an elevated location in a wastewater system, the biogas being released from wastewater passing though the collector chamber. The methods may include the step of controlling the withdrawing of biogas from the collector chamber, and the step of capturing the biogas withdrawn from the collector chamber. The methods may include performing the step of collecting biogas within a collector chamber of a biogas collector by reducing a pressure within at least portions of the collector chamber. The methods may include the step of conveying biogas withdrawn from the collector chamber to a biogas disposer. Related apparatus for capture of biogas from a wastewater system are disclosed herein.

A multi-stage anaerobic digester is designed to treat a high solids, stackable feedstock. The system may also receive a pumpable feedstock such as a slurry or sludge. In a first stage, the digestate circulates in one direction around a raceway such that the digestate may pass a feed inlet multiple times before leaving the first tank. An optional side stream loop withdraws fibrous material from near the top of the reaceway and return digestate with chopped fibers, preferably lower and further along the raceway. An outlet from the raceway located near, but upstream of the feed inlet discharges partially digested substrate to a second stage, which is operated as a stirred tank reactor. The two stages may be provided in a single tank with an internal wall separating a ring shaped outer portion from a cylindrical inner portion. The digester may be operated in a thermophilic temperature range.

A waste stream is treated by anaerobic digestion. A process is described involves a step of separating solids from digestate, and returning separated solids to a digester. Optionally, there may be a step of solids separation in which larger solids are removed from the digester. A process and apparatus are described for treating waste sludge from a wastewater treatment plant in an anaerobic digester. Feed sludge is thickened or solids are separated from digestate and returned to the digester. Additional co-digestion waste may be added to the digester. The process and apparatus may be used in a retrofit of an existing wastewater treatment plant.

A method enhancing biological digestion of wastewater sludge is provided. The method uses chlorine dioxide to accelerate and improve the efficiency of aerobic or anaerobic digestion.