Biological aerated filters (BAFs) can combine ammonia, carbonaceous matter, and solids removal in a single-unit process. Biological nutrient removal (N and P) can also be accomplished. Removal rates based on reactor volume for carbonaceous BOD, ammonia, and nitrates of up to 4.1 kg BOD m⁻³ day⁻¹, 1.27 kg NH3-N m⁻³ day⁻¹ and 5 kg NO3-N m⁻³ day⁻¹, respectively, are normally reported. The small footprint and adaptability of BAFs allows them to be used in upgrading established works, especially those in built up areas where space is at a premium. Although many configurations are available, including upflow and downflow, sunken, and floating media, the process still requires some optimization, especially with regard to media type, backwashing rates, and aeration control to decrease power consumption. Key words: biological aerated filter; wastewater treatment; submerged media bioreactor; carbonaceous matter removal; nitrification

The effect of the use of treated wastewater on the growth of cabernet sauvignon and merlot grapes from the Guadalupe Valley, Mexico was evaluated. Secondary advanced effluent was used to irrigate the grapevines at a rate of 66 L/vine/week. Wastewater quality results confirmed that all parameters complied with Mexican legislation for crop irrigation as well as reuse in activities in which the public would be in direct or indirect contact with the reclaimed water. Results showed that the number of leaves per shoot and the overall biomass increased in plants irrigated with wastewater and grape production per plant was 20% higher. The concentration of carbohydrates, organic acids and pH were similar in grapes from vines irrigated with wastewater to those irrigated with groundwater. Throughout the experiment, no fecal coliform bacteria were detected in the cultivated grapes. The wastewater caused an increase in the biomass of the grapevines and there was no presence of microbial indicators in the final product so a higher wine production could be achieved without an increase in health risk related problems. If 200 L/s of reclaimed wastewater would be returned to be used for grapevine irrigation in Valle de Guadalupe (the same amount that is currently being sent as drinking water to Ensenada), assuming an irrigation application of 6,000–7.500 m3/ha/year, approximately 837–1046 hectares (ha) of grapevines could be irrigated. Part of ongoing research includes an economical analysis of the best options for Ensenada and the Valle de Guadalupe in order to establish the optimum volume of water to be returned, the cost of its transportation, as well as the cost of irrigation.