P18414: SOIL Composting Toilet and Urine Management

Problem Definition

Table of Contents

This webpage is an organized summary of all the work done during the first phase, Problem Definition. This page will serve as the presentation, including descriptions of each deliverable for the Problem Definition phase, image summaries of our work, and links and downloads of full versions of any relevant documents.

Team Vision for Problem Definition Phase


Project Summary

Sustainable Organic Integrated Livelihoods (SOIL) is working to alleviate the severe lack of adequate sanitation facilities in urban Haiti by means of providing a portable dry toilet, designed to separate urine from feces, to households. Current models have received a 50% satisfaction rating without being the most cost-effective to manufacture, urging SOIL to entertain improvements to the design to better the current system. Excrement buckets are collected by SOIL employees while the urine is managed by the household, often being disposed of in the surrounding environment. A seat model was developed in 2005 which, along with other tested models, is too expensive to produce, does not sustainably manage urine and is not consistently effective for all users.This product and service pairing is intended to help reduce the spread of disease, repurpose the nutrients in urine, and improve the standard of living both in homes and the overall communities involved.

The goal of this project is to review relevant alternatives, consider feedback from users and improve upon the current system to improve ergonomics, increase separator efficiency, utilize effective means of recycling the nutrients from urine, reduce cost of production, and harbor a holistically sanitary experience. The expected end result is a functional prototype which can be produced and practiced for use.

The full pdf of the Project Summary can be found here.

Use Cases

It was important to identify different use cases throughout the design process to consider many of the possible outcomes that our project could encounter. Several use cases were outlined by the team including:

A general use case can be seen below:

General Use Case

General Use Case


A more specific use case can be seen below:

Specific Use Case

Specific Use Case


The full document of our use cases can be seen here.

Project Goals and Key Deliverables

Customer Requirements (Needs)


The Customer Requirements were created with the goal of identifying desired product design elements to satisfy the end customer to the fullest extent.

When deciding upon the customer requirements, several factors were taken into consideration. An interview was conducted with a current SOIL employee. This person had personal experience in interacting with customers of the product.

The interview questions with typed notes can be found here.

From this interview, customer requirements were generated and assigned a priority of 1,3,9; 9 being a top priority, and 1 being lowest priority. These assigned priorities will be used in the House of Quality.

The table of the sorted customer requirements can be seen below.

Customer Requirements

Customer Requirements

In addition to a snapshot, a link to the live document is included here. This spreadsheet also includes our table on organized engineering metrics.

Engineering Requirements (Metrics & Specifications)


Create a contract between the engineer and the customer where indisputable satisfaction of the engineering requirements equates to customer satisfaction
Engineering Metrics

Engineering Metrics

A download link to our team's designated engineering metrics can be found here. This spreadsheet also includes our table on organized customer requirements.


House of Quality

Our House of Quality was designed with the purpose of providing insight as to what aspects of the design need to be prioritized. This was done through the process of comparing the customer requirements to the engineering metrics.

Through continued research and discussion, the initial prioritized table was expanded into the full House of Quality.

An image of our summarized HoQ can be seen below:

House of Quality

The full House of Quality document can be downloaded here.


  1. Confirm that satisfaction of the Engineering Requirements implies that all of the Customer Requirements are met.
  2. Facilitate design trade off decisions

Design Review Materials

Our Problem Definition Phase review will be held September 18, 2017 at 2:30 pm in GLE-4425.

Comments and Constructive Criticism

This section will be populated post review.


While benchmarking was done in consideration with both customer requirements and engineering metrics, for organizational purposes, it was decided that benchmarking would be included in its own section of this webpage.

Benchmarking is necessary for the design process because it draws inspiration from other similar products and notes what is successful and unsuccessful in each. This can help to optimize our own design for SOIL.

Benchmarking on customer requirements can be seen below:

Benchmarking for Customer Requirements

Benchmarking on engineering metrics can be seen below:

Benchmarking for Engineering Metrics

Additional research on benchmarking can be seen in the attachment here.

Risk Management


For planning Risk Management it was important to consider all the realistic causes of product failure. This is necessary for planning into the next phase of this project to weigh the prevalence of risk with the likelihood of occurrence.

A simplified image of the categorized risks can be seen below:

Risk Assessment

A completed table of organized risks can be downloaded here.

Plans for next phase

Systems Design Phase Project






Home | Planning & Execution | Imagine RIT

Problem Definition | Systems Design | Preliminary Detailed Design | Detailed Design

Build & Test Prep | Subsystem Build & Test | Integrated System Build & Test | Customer Handoff & Final Project Documentation

The Problem Definition Documents directory will provide a link to all uploaded documents for our team during this first phase.