BACKGROUND

Clean water used by personnel performing labor at oil and gas well sites is commonly delivered and stored in water tanks at the well site. Water is also needed at well sites during drilling operations for drilling fluid, also called drilling mud. The purchase, delivery, and storage of water at well sites can be a significant part of overhead associated with drilling operations.

Many tasks and operations at oil and gas well sites, including drilling operations, require human labor. The presence of personnel at the well site and their water needs may vary. Most if not all personnel at well sites require the use of on-site restrooms. Personnel residing at well sites over multiple days require running water for drinking, cooking, cleaning dishes, and washing clothes. Consequently, human activity at oil and gas well sites commonly results in at least two types of wastewater: blackwater and greywater.

Blackwater results from restrooms and is wastewater containing feces, urine and flushwater from flush toilets or toilet paper. Greywater or sullage is generally wastewater generated in households or office buildings from streams without fecal contamination, i.e. all streams except for the wastewater from toilets. Greywater may include the wastewater resulting from cleaning dishes and washing clothes. Blackwater and greywater are to be distinguished from “produced water,” which term is used in the oil industry to describe water that is produced as a byproduct along with the oil and gas.

Generally, blackwater and greywater resulting from human activity cannot simply be disposed of at an oil or gas well site; rather, industry practice has been to collect the wastewater in holding tanks and then transport it to remote locations for treatment. Often municipal water treatment facilities are contracted to receive and treat blackwater and greywater. The cost for wastewater transport services and to compensate municipal wastewater treatment facilities can significantly increase overhead for well site operations.

There are a number of challenges with collecting and treating blackwater and greywater. Treatment of such wastewater has often had to rely on municipal water treatment facilities or other more permanent water treatment systems. Such facilities may be permanently located at great distances from remote well sites. Further, the water treatment facilities are generally not built for specific well sites or groups of well sites because of the extensive resources and costs to build them. Likewise, the tentative viability of well sites and scarcity of well sites in a given group to be served make it infeasible to build permanent water treatment facilities for specific well sites or groups of well sites. Once a water treatment facility is built, it is usually fixed to a location and cannot be transported to new sites when needed.

Also, greywater from certain greywater sources at well sites contains substantial amounts of diesel, oil, grease, cuttings, and or drilling mud. Some of these contaminants, such as diesel, kill or otherwise inhibit growth of bacteria and other microorganisms useful for the treatment of waste water.

SUMMARY

A bioreactor for a water treatment system is disclosed. The bioreactor includes an aerator tank configured to receive an influent liquid, and a clarifier positioned in the aerator tank, the clarifier having a generally conical shape and defining a downwardly-facing opening. An interior of the clarifier is in communication with the aerator tank, external to the clarifier, at least via the downwardly-facing opening, and wherein the clarifier is positioned non-concentrically with the aerator tank. The bioreactor further includes a plurality of aeration vents positioned proximal to a bottom of the tank and configured to direct air into the aerator tank, and an effluent outlet positioned in the clarifier. A relatively clean effluent liquid, in comparison to the influent liquid in the aerator tank, exits from the clarifier via the effluent outlet.

A water treatment system is also disclosed. The system includes a bioreactor including an aerator tank configured to receive an influent liquid, and a first clarifier positioned in the aerator tank, the first clarifier having a generally conical shape and defining a downwardly-facing opening. An interior of the first clarifier is in communication with the aerator tank, external to the first clarifier, at least via the downwardly-facing opening. The first clarifier is positioned non-concentrically with the aerator tank. The bioreactor also includes a plurality of aeration vents positioned proximal to a bottom of the tank and configured to direct air into the aerator tank, and an effluent outlet positioned in the clarifier. A relatively clean effluent liquid, in comparison to the influent liquid in the aerator tank, exits from the clarifier via the effluent outlet. The system further includes a second clarifier in communication with the effluent outlet of the clarifier of the bioreactor, a filter tank in fluid communication with the second clarifier, an ultraviolet (UV) filter in fluid communication with the filter tank, a chlorinator in fluid communication with the UV filter, and a transfer tank in fluid communication with the chlorinator.

