Trace organic contaminant removal from drinking water using local char

Transcription

1 Trace organic contaminant removal from drinking water using local char or Toxic organic chemical contaminants: The biggest problem you re completely unaware of J.P. Kearns, K.K. Shimabuku, R.B. Mahoney, N.W. Reents, R.S. Summers, D.R.U. Knappe! Josh Kearns, MS, PhD student Environmental Engineering, University of Colorado Visi<ng Researcher, North Carolina State University Director of Science, Aqueous Solu<ons (+1) Skype: joshkearns

2 "I wouldn t expect that herbicide would be a big risk in most developing countries. - are Tawney, Managing Editor, Waterlines Journal, in an dated Sept. 5, >300 million tonnes of synthe<c organic contaminants (SOCs) produced annually, including >5 million tonnes of pes<cides cons;tute a major impairment to water quality on a global scale. - - Schwarzenbach et al., 2006, Science 313, 1072 Pes<cide pollu<on appears twice in the Top Ten in The World s Worst Toxic Pollu;on Problems Report - - Blacksmith Ins<tute/Green Cross Switzerland, 2011 Exposure to trace quan<<es of SOCs can lead to cancer, diseases of the endocrine and reproduc<ve systems, and damage to the liver, kidneys, or central nervous system, and other toxic effects - - Centers for Disease Control and Preven<on, 2009/2013 Around 75% of the pes<cides used in S/SE Asia are banned or heavily restricted in the West due to ecological and human health effects - - Pes<cide Ac<on Network, 1997 Addi<onally, naturally occurring algal/cyanobacterial metabolites such as 2- methylisoborneol (MIB) and disinfectants such as chlorine can adversely impact water organolep<cs. Objec<onable taste and odor has played a major role in the decline of household safe water prac<ces. Trace organic contaminants are a major blind spot and Achilles heel for the WASH sector a>emp?ng to provide safe drinking water. See our paper: Kearns, Knappe, and Summers SyntheCc organic water contaminants in developing communices: an overlooked challenge addressed by adsorpcon with locally generated char. Journal of Water, Sanita?on & Hygiene for Development, Vol. 4, Is. 3. 2

3 Micro MulC- Barrier Water Treatment Plant 2,000-3,000 L/day cost: US$ 400, local materials open- access handbooks available at aqsolucons.org English, Spanish, Thai, Burmese, and Karen transla<ons available so far This treatment system at a farm community in northern Thailand has been in continuous operation since February To-date it has produced over 2.36 million liters of treated water. Considering the typical local price for purchasing bottled water, this corresponds to a cost savings of over US$ 44,300 - for a system that has cost less than US$ 500 to install and maintain. 3

4 Nano Portable/Emergency Water Treatment Plant L/day cost: US$ 125, local materials open- access handbooks available at aqsolucons.org English, Spanish, Thai, Burmese, and Karen transla<ons available so far Since March 2012, about 25 of these systems have been installed in re m o t e c o m m u n i t i e s, t r a i n i n g centers, school and villages throughout the Thailand-Burma border region. To-date these systems have produced an estimated 2 to 3.4 million liters of treated water. 4

5 brick beehive kiln steel drum/adobe kiln gasifier cookstove gasifier drum oven 5

6 500 μm char made from longan wood accvated carbon 500 μm high temperature chars can exhibit extensive micro- porosity and large internal surface area and thereby make effec<ve adsorbents for trace organic pollutants 6

7 Sorp<on of select organic water contaminants by biochars... Probe compound selec<on criteria from a water treatment perspec<ve: environmental relevance - widely occurring nega<ve human health impact impair water aesthe<cs difficult to remove 2,4- D herbicide possible carcinogen, suspected endocrine disruptor USEPA MCL 70 μg/l WHO Guideline 30 μg/l pk a 2.7 warfarin (WFN) an<coagulant, roden<cide pk a 5.1 trihalomethanes (THMs) disinfec<on by- products (DBPs) USEPA MCL 80 μg/l total THMs (TTHMs) chloroform probable carcinogen BDCM probable carcinogen CDBM possible carcinogen sulfamethoxazole (SMX) an<bio<c (humans and livestock) pk a methyl isoborneol (MIB) cyanobacteria metabolite not a health concern musty taste & odor at >10 ng/l bromoform probable carcinogen Br 7

8 sorp9on#capacity#rela9ve#to#ac#(%)# 100# 10# 1# LT# IT# HT# LT# IT# HT# LT# IT# HT# LT# IT# HT# LT# IT# HT# Trace contaminant adsorp<on capacity rela<ve to commercial ac<vated carbon (AC) as a func<on of pyrolysis temperature for low temp (LT, 350 C), intermed. temp (IT, 625 C), and high temp. (HT, 900 C) chars. 0.1# 2,4- D 2,4,D# SMX# WFN# MIB# TTHMs# trihalomethanes (THMs) disinfec<on by- products (DBPs) chloroform 2,4- D herbicide BDCM sulfamethoxazole (SMX) an<bio<c (humans and livestock) warfarin (WFN) an<coagulant, roden<cide 2- methyl isoborneol (MIB) cyanobacteria metabolite taste & odor concern CDBM bromoform Br 8 8

9 Summary and Conclusions High temperature (900 o C) gasifier chars made from wood can have % the capacity of commercial AC for sorbing a variety of commonly occurring and difficult to treat organic contaminants of concern to the drinking water community. Intermediate and low temperature chars are substan<ally less effec<ve sorbents. Biochar in par;cular, high temperature gasifier char has great poten;al as a low- cost adsorbent for use in water treatment.

10 Summary and Conclusions The WASH sector must address harmful trace organic contaminants in safe water programming! The use of biochar can promote microbial risk reduc;on through greater acceptance of - based disinfec<on due to improved water aesthe<cs chemical risk reduc;on associated with exposure to toxic disinfec<on by- products and trace organics 10

11 Trace organic contaminant removal from drinking water using local char Ques;ons? Josh Kearns, MS, PhD student Environmental Engineering, University of Colorado Visi<ng Researcher, North Carolina State University Director of Science, Aqueous Solu<ons (+1) Skype: joshkearns 11