1. Toilets, Urinals, and Primary Waste Management

Toilets, Urinals, and Primary Waste Management


Overview

The majority of space within the facility will be allotted to toilet stalls, which address the largest sanitation deficit and expressed desire for services in the Redevelopment Seed and across the Park (Granfone et al, 2008). The main ideas include composting as a water-free sanitation solution, diverting urine to speed composting while also creating two separate resources in the form of urine as fertilizer and composted feces as soil amendment for urban agriculture. In addition the management of odors will be considered as this is a key to social acceptability.

 

 Toilets


System Components

  • Urine Divergent Toilet
    • Purchase urine divergent inserts similar to SEP Insert
    • Design a lever that directs the flow to separate pipes
  • Urine Collection
    • Use 200L drums to collect urine
    • Piping from all toilets to single barrel
    • Shutoff or alarm to signal full urine barrel
  • Solid Waste Collection
    • Use 200L drums to collect solids
  • Ventilation control
    • Direct the flow of air using carefully designed passive and electric powered fans
  • Waste Transportation
    • Low profile drum carts similar to Beacon Drum Hand Cart
    • One cart per drum plus cart or dolly for moving urine barrels


Design Considerations and Specifications

  • Target Usage: 200 users
  • Expected Daily Volume: Feces 24 Kilograms, Urine 220 Litres 
  • Number of Stalls: 5 of our design, 1 Enviro-loo for Handicap access, and 1 EcoSan for clinic use
  • Facility Height: Stalls on raised platform of approximately 1.5 metres for sublevel access
  • Stall Dimensions: 0.9 metres in width x 1.7 metres in length
  • Front Walkway Width: Approximately 1 metre
  • Facility Dimensions: Five Stalls, Approximately 5 metres x 2 metres
  • Stall Classifications: Easily cleanable surfaces. Appealing and clean looking.


Operational Plan

  • Maintenance:
    • Stalls cleaned and stocked with toilet paper daily by caretaker
    • Carbon source added to toilets daily as bulking and drying agent, and to achieve appropriate C:N ratio. Carbon source ideally to be plant matter grown in grey water biofilter, or alternatively wood shavings
    • Waste and carbon material may need to be mixed occasionally by caretaker
  • Waste Removal and Monitoring: 
    • Volume levels observed daily
    • Barrels moved to composting area when they reach desired volume


Experimental Research Recommendations

  • Testing
    • Define need for urine divergence.
      • Examine the effect of urine on the composting process to determine if urine helps composting. For each case evaluate amount of carbon additive needed, changes in compost time, changes in compost temperature quality of compost, and volume reduction or increase. 
    • Experiment with container design
      • Examine the effect of container design on the composting process to determine the most effective design.
      • Evaluate cost, compost temperature, compost quality and ease of use. 
    • Define ideal volume of compost in container
      • Examine the effect of airspace in the composting container on the composting process to determine the ideal fill volume.
      • Evaluate compost quality, compost time, and compost temperature.


  • Data Collected
    • Volume of Solid Waste
    • Volume of Liquid Waste


Background Research & Discussion

In order to determine the number of toilet stalls and urinals required for the Sanitation Centre, their gender or age specifications, and their individual dimensions, a combination of professional specifications and case study examples were considered.

The Dutch MobiSan Project precedent for dry sanitation designs was equipped with 13 toilet stalls and 12 urinals for a load of 500 community members. Due to its experimental nature, our facility was designed to handle a user load of 200 people with seven toilet stalls, while expressed uncertainty surrounding the resident’s use of urinals limited our allocations to two men’s urinals.

The MobiSan further allotted its stalls to specific genders and ages with some success. There were stalls designed specifically as women’s urinals, ordinary women’s stalls, men’s stalls, and children stalls containing potty seats and steps for the younger residents. Our sanitation facility would also seek to employ this division by designing a children’s stall with stairs and a child-friendly seat, two ordinary women’s stalls, two ordinary men’s stalls, a handicap-accessible stall, and a clinic stall – all employing urine divergent toilet schemes.

Based on a consultation with EcoBeam project manager Robert Taylor, the standard spatial requirements for toilet stalls are approximately 0.9 metres in width and 1.7 metres in length. This provided length is also expected to accommodate inward-swinging stall doors, which Robert assured to be absolutely necessary in Monwabisi’s extremely windy environment. At these estimations, we can fit five toilet stalls within the identified five metre section of wall abutting the Community Centre with potential expansion capacity of two to four more, which would require modification of the windows in the medical clinic.

Odor control within these stalls is also a major design consideration. The collection containers will be located in an airflow-controlled environment to assure no foul odors advance into the stall. Vent pipes are to be located close to the drop of each toilet and run up the community centre wall to be vented above the highest roof point, about 9 metres above the ground. A combination of wind-driven and electrically powered exhaust fans will be used to minimize electricity use while assuring adequate ventilation during low wind conditions. The dual fan system also allows the wind powered fans to keep the odor controlled in the event of a power shortage. One possible scheme to ensure proper ventilation would be to direct the vent pipes from each stall to a single common pipe that is then ventilated using a series of both fans.

The solid waste passing through these toilets will be collected within individual sublevel containers, while urine will be collected in similar containers and stored a short distance from the toilet stalls. According to a study done at the University of Connecticut, the average per capita human excrement per day was recorded to be 120 grams or 4.4 oz of feces and 1.1 liter or 2.3 pints of urine. A more recent study was performed in Thailand that found the same waste quantities confirming that, although there can be fluctuations in these values based on age and diet, the average remains fairly constant. Thus the use of 200 litre drums has been proposed for the accommodation of these substantial volumes of waste due to their availability and relative mobility.

To read more about the MobiSan Project, click here.

 

– Toilets, Urinals, and Primary Waste Management – Composting & Pasteurization – Improved Taps – Hand Washing Station – Laundry Station – Grey Water Management Scheme– Caretaker Office – Facility Perimeter –