Environment and Community-Friendly Wastewater Treatment

EPA Grant Number: SU839486
Title: Environment and Community-Friendly Wastewater Treatment
Investigators: Weber-Shirk, Dr. Monroe
Institution: Cornell University
EPA Project Officer: Page, Angela
Phase: II
Project Period: April 1, 2019 through March 31, 2021
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2018) Recipients Lists
Research Category: P3 Challenge Area - Water , P3 Awards

Objective:

AguaClara Cornell researched a variety of bioreactor types and selected the Upflow Anaerobic Sludge Blanket (UASB) bioreactor as the most promising core technology for a distributed wastewater treatment system for small communities. The UASB was chosen because of its: (1) efficiency for organics removal, (2) low cost, (3) simplicity of design, and (4) the fact that there is a value added product (biogas for cooking, lighting, heating) that could motivate adoption of the technology. UASB reactors treat wastewater biologically, using anaerobic bacteria to break down organic matter and converting the majority of it to biogas. Methane comprises 60-70% of the resulting biogas content, and can be used as fuel for heating, lighting, or cooking. However, getting UASB designs to work robustly without electricity and at very small scales (a few households to dozens of households) is a challenge not yet well addressed by existing designs. Though large scale centralized UASB systems, such as those installed in Brazil and India, often include pumping and electronic controls, they can be designed as gravity powered systems which are much more attractive to small communities with unreliable electricity access.

We hypothesize that:

1.UASBs can be operated without electricity if designed appropriately to use gravity head to distribute influent wastewater.

2. A UASB that is treating waste for about 15 people will be able to provide cooking fuel for one household.

3.We hypothesize that UASB inlet system design (fluid velocities, manifold design, and flow intermittency) has a significant effect on the hydraulic residence time and treatment efficiency in the sludge bed.

4.We hypothesize that solid/liquid separation would be improved if it were accomplished in a zone that was free of gas bubbles.

5. We hypothesize that Fats/Oils/Grease, FOG, can be removed with a surface drain.

Approach:

The hypothesis related to improve the hydraulic residence time by reducing short circuiting provides a significant opportunity for improving UASB performance. This hypothesis will be tested initially in scale models in transparent reactors and using a tracer and simulated settled sludge beds to measure the tracer residence time of different designs. After characterization of the failure modes and dominant length scales we will first demonstrate a successful design at bench scale and then design and build pilot scale reactors.

Pilot plants will be tested and their performance compared at the Ithaca Area Wastewater Treatment Facility (IAWWTF). (IAWWTF) staff and lab workers will monitor performance and recommend design improvements. An improved design will be tested in a Honduran community in collaboration with the Honduran Water Ministry and Agua Para el Pueblo. Data collected will provide crucial insight into how these systems work in community settings, and will inform final design decisions before implementation of these reactors in communities on a larger scale.

Expected Results:

Goal #1: Improving the influent dosing system, reducing short circuiting, and improving the removal of floatables (UASB 2.0 design)

Goal #2: Characterizing startup and performance of the UASB reactors with these innovation.

Goal #3: Determining appropriate options for effluent post treatment and biogas utilization

Goal #4: Iterating designs and installing and testing a distributed UASB in Honduras

The proposed work is designed to meet the need for a higher performing and lower cost wastewater treatment system. We will build on our open source approach that we have used to create the next generation of drinking water treatment technologies. Our expertise in linking user feedback, advanced reactor design, and context specific construction methods will enable us to create innovative and useful solutions.

Supplemental Keywords:

Biogas, UASB, sustainable development, pathogens, watersheds, aquatic ecosystem, waste reduction


P3 Phase I:

Climate & Community Friendly Wastewater Treatment