A single-stage continuous aeration-batch clarification process for purifying wastewater containing pollutants includes the steps of continuously aerating the wastewater in the presence of biologically active solids and powdered absorbent in an aeration zone. A portion of the mixture of wastewater, biologically active solids and powdered absorbent is transferred to a settling zone where a settled solids phase and a clarified liquid phase are formed. During the settling step additional wastewater flows into the aeration zone. The clarified liquid phase is discharged from the settling zone while the settled solids phase may be returned to the aeration zone or sent to disposal. The process may be carried out with a single aeration basin and settling basin or with a plurality of aeration basins using a single settling basin.
A process is described for aerobically treating wastewater containing volatile compounds to degrade the volatile compounds without liberating them to the atmosphere. Influent wastewater and return sludge from an aerobic biophysical wastewater treatment system are contacted in a preaeration zone where a minimum dissolved oxygen concentration of about 1 mg/l is maintained. In this preaeration zone a significant portion of the volatile compounds are biologically degraded. The minimum oxygen concentration in the preaeration zone is attained by prior aeration of the return sludge or by adding a small amount of oxygen to the preaeration zone. The mixture of influent wastewater and biophysical solids depleted of volatile compounds then flows to an aeration zone for further removal of pollutants.
A process is described for the operation of a multiple zone batch treatment system for biological or biophysical treatment of wastewater. The system comprises two or more batch treatment zones with wastewater passing sequentially through all treatment zones. After the mix and settle batch steps occur for all zones, influent wastewater flows into the first zone and displaces clarified wastewater in a plug flow mode through each treatment zone and ultimately from the last zone. The combining of the decant and fill steps for all or most of the zones provides for shorter cycle times and greater capacity for the system.
An automated wastewater treatment miniplant intended for installation and use with individual residences. Wastewater such as raw sewage is received in a settling tank to remove suspended solids, and then flows to an intermediate tank where the sewage is aerated and churned to promote aerobic treatment of organic materials in the sewage. When the wastewater in the intermediate tank reaches a predetermined level, a batch of that wastewater is transferred to an aerator-clarifier tank where further aerobic treatment of the batch wastewater occurs under controlled conditions, without dilution with incoming wastewater. Further aerobic decomposition of the wastewater takes place in the aerator-clarifier tank. Sludge is allowed to settle in that tank, and supernatant liquid within that tank is periodically withdrawn for dispersal in a drain field. Sludge is periodically returned to the intermediate tank to augment the biomass in that tank. Some sludge is periodically wasted from the system. The wastewater treatment miniplant optionally includes a separate tank for receiving and disinfecting supernatant liquid withdrawn from the aerator-clarifier tank. That disinfected liquid is dispersed in an underground irrigation field or in a drain field. The miniplant is automated under microprocessor control, and can report faults to a central location and exchange other information with the central location.
A physical-biochemical process system and apparatus for removal of toxic volatile organic compounds (VOCs) and other organics from contaminated groundwater or wastewater is described. This process system involves influent pumping groundwater or wastewater treatment by air stripping, biological oxidation and powdered activated carbon (PAC) adsorption in an enclosed gas stripping bioreactor, air purification by granular activated carbon contactor, and recycling of GAC-purified air for further groundwater or wastewater treatment. The bioreactor effluent is processed processed by a clarifier, a filter and a disinfection unit. The clarifier sludge is partially recycled to the bioreactor and partially wasted. The process system is cost-effective and eliminates the problem of secondary air contamination caused by conventional gas stripping tower and coventional biological treatment processes.
A wastewater treatment system for treating a wastewater stream from industrial and municipal sources uses a control system to sequence and supervise the treatment steps in a batch flow mode of operation or a continuous flow mode of operation. In operation, the wastewater treatment system predominantly operates in the batch flow mode. However, the wastewater treatment system operates in a continuous flow mode when the influent wastewater stream exceeds the system's nominal design flow transition point. The control system receives an input signal, relating to the influent flow rate, and switches one or more reactors of the wastewater treatment system from the batch flow mode to a continuous flow mode according to a control algorithm.
