OPEN HOUSE & STUDENT RECOGNITION MAY 5 @ 9:00am - 3:00pm > Oro Loma/Castro Valley Treatment Facility 2600 Grant Avenue, San Lorenzo, CA 94580 Treatment Plant Tours: Get a first-hand look at how the water pollution control facility works. Tours every 30 minutes. Hands-On Activities: Test your recycling skills and see a robotic sewer inspection camera and a Waste Management truck. Student Recognition: Every hour on the hour, 9:00am - 2:00pm. Complimentary Eats and Treats: Hot dogs, cookies, sodas, shaved ice, coffee.