Aerobic Bio-Composting Toilet An affordable toilet solution to sustain ODF - Bimal Tandukar, Rural Sanitation Specialist (PIC) Second Rural Water Supply and Sanitation Sector Project (AF), Ministry of Rural Development/ADB, Cambodia. bimal.tandukar@gmail.com Theme: Hi- and low-tech solutions in urban/rural environment Global Dry Toilet Conference, Tampere, Finland 22-24 August 2018
Aerobic Bio-Composting (ABC) Digester: How it works? Solid and liquid are separated by graded filter medium. Feces converted into compost by micro and macro oganisms, fungus etc. under aerobic condition. Filtered effluent soaked underground or used for irrigation. Compost (approx. 4-5 lit/per/yr) produced can be treated using hydrated lime (CaOH 2 ) for agriculture use.
AEROBIC BIO-COMPOSTING (ABC) DIGESTER Two cases Installation of ABC with graded filter media and proper ventilation in digester, Pursat. September 2015. HH : 4 Users Concrete factory: 8 users. Kampot. Nov 2015 Inside digester: Fungus and micorizers, December 2015 Digested fecal sludge inside ABC Digester, Pursat, June 2017 Maggots were observed in ABC, Kampot, July 2017.
Undigested sludge Inside Digester Maggots Odourless digested compost within 7 hrs of use
Lab test results of Compost from ABC, April 2018, Pursat Province (Sep 2015 Apr 2018) PARAMETERS UNIT TEST RESULT TEST METHOD 1. NITRATE (NO3) (mg/l) 5.17 Spectrophotometry 2. PHOSPHATE (PO4) (mg/l) 1.26 Spectrophotometry, AOAC 3. BOD5 (mg/l) 310 Manometry, Wagtech UK 4. E-COLI (cfu/g) 2.9x10 3 Rapid E-Coli 2 media 5. HELMINTH EGG (Eggs/gm) Not Seen Microscopic Observation Note: Samples were tested in Research and Innovation Centre, Phnom Penh, Cambodia, April 2018
Post ODF Challenges
Case from Banteay Meas District (1 st ODF District in Cambodia), Kampot Province. SNV-IRC 2015 92% FS from emptied toilet pit disposed in open environment without treatment
CAMBODIA Area: 181,035 square kilometers Population: 16 million (approx.) National Sanitation Coverage: 49% Open Defecation: 41% Urban Population: 21% (Source: JMP 2017 as of data 2015) Flood prone area + Floating village: 43-49% population (WSP 2011)
Sanitation in Challenging Environment HHs in Flood Prone Area Floating village
FLOOD PRONE AREA August 2017 School building February 2018
Application of the concept in Lake based communities: Boat based Aerobic Bio-Composting (BABC) Digester Typical toilet in floating community. Government Officials observing different floating toilet models ready to be tested in Cambodia, December 2017. Demonstration of BABC, Mar 2018.
Lab test results of effluent from boat based digesters and lake water, Pursat Province Toilets installed in March 2018, lab test conducted in May 2018 PARAMETERS 1. TOTAL SUSPENDED SOLIDS UNIT EFFLUENT BABC HYB EFFLUENT BABC mg/l 95 135 85 2. BOD mg/l 378 825 45 3. COD mg/l 540 1300 110 4. NITRATE (NO3) mg/l 2.35 5.45 3.65 5. PHOSPHATE (PO4) mg/l 15.5 45 0.6 6. E-COLI MPN/ 100ml 9.2x10 4 8x10 5 2.5x10 4 WATER 20M OFFSHORE GOC standard for waste water disposal <120 <80 <100 <20 <6 NA
ABC Digester :Comparative Advantages AFFORDABLE: Low cost digester (US$ 30-70 for land based and US$ 100-150 for lake based), avoids cost of pit emptying in the long run. Low maintenance cost. CONVENIENT: Easy to install. Odourless compost 4-5 lit/per/yr. ENVIRONMENT FRIENDLY: Onsite treatment. Compost can be used for agriculture with simple lime treatment at HH level, no emission of Green House Gas (methane). Nutrients recovery. REPLICABLE: Used locally available materials in rural market, can easily modify conventional concrete pit latrine into ABC. Can be retrofitted in existing toilet. INNOVATIVE: Only the available potential sanitation solution for floating and flood prone area, where conventional sanitation options do not work.
Potential of vegetables farming and nutrient recovery from BABC on Boat
ACKNOWLEDGEMENTS TO: Ministry of Rural Development, Royal Government of Cambodia Asian Development Bank Bill and Melinda Gates Foundation EGIS EAU SNV Netherlands Development Organisation Thank you