title: Reverse osmosis and ultrafiltration for recovery and reuse of larval rearing water in Anopheles arabiensis mass production: Effect of water quality on larval development and fitness of emerging adults.
abstract: BACKGROUND
  Countries around the world are showing increased interest in applying the sterile insect technique against mosquito disease vectors. Many countries in which mosquitoes are endemic, and so where vector control using the sterile insect technique may be considered, are located in arid zones where water provision can be costly or unreliable. Water reuse provides an alternate form of water supply. In order to reduce the cost of mass rearing of Anopheles arabiensis mosquitoes, the possibility of recycling and reusing larval rearing water was explored.
  
  
  METHODS
  The used rearing water ('dirty water') was collected after the tilting of rearing trays for collection of larvae/pupae, and larvae/pupae separation events and underwent treatment processes consisting of ultrafiltration and reverse osmosis. First-instar An. arabiensis larvae were randomly assigned to different water-type treatments, 500 larvae per laboratory rearing tray: 'clean' dechlorinated water, routinely used in rearing; dirty water; and 'recycled' dirty water treated using reverse osmosis and ultrafiltration. Several parameters of insect quality were then compared: larval development, pupation rate, adult emergence, body size and longevity. Water quality of the samples was analyzed in terms of ammonia, nitrite, nitrate, sulphate, dissolved oxygen, chloride, and phosphate concentrations after the larvae had all pupated or died. Surface water temperatures were also recorded continuously during larval development.
  
  
  RESULTS
  Pupation rates and adult emergence were similar in all water treatments. Adult body sizes of larvae reared in recycled water were similar to those reared in clean water, but larger than those reared in the dirty larval water treatment, whereas the adult longevity of larvae reared in recycled water was significantly increased relative to both 'clean' and 'dirty' water. Dirty larval water contained significantly higher concentrations of ammonium, sulfate, phosphate and chloride and lower levels of dissolved oxygen than clean water. These parameters significantly varied during the period of larval development. After dirty water was recycled by ultrafiltration and reverse osmosis, all the parameters measured were the same as those in clean water.
  
  
  CONCLUSIONS
  This study demonstrated the potential for using recycled larval rearing water to supplement clean dechlorinated water supplies. Recycling used water improved its quality and of the reared mosquitoes. As water demands and environmental pressures grow, recycling of larval rearing water will improve the sustainability and affordability of mosquito mass-rearing.
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria; Institut de Recherche Agricole pour le Développement (IRAD), Yaoundé, Cameroon. Electronic address: mwjosephfr@yahoo.fr.
authors.forename: Wadaka
authors.initials: W
authors.lastname: Mamai
authors.affiliation: Austrian Institute of Technology, Energy Department, Environmental Resources & Technologies, Tulln, Austria. Electronic address: Rebecca.Hood@ait.ac.at.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Hood-Nowotny
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: maigahamid@yahoo.fr.
authors.forename: Hamidou
authors.initials: H
authors.lastname: Maiga
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: adel_barakat2005@yahoo.com.
authors.forename: Adel Barakat
authors.initials: AB
authors.lastname: Ali
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: nansevbis@gmail.com.
authors.forename: Nanwintoun S
authors.initials: NS
authors.lastname: Bimbile-Somda
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: dieusoma@yahoo.fr.
authors.forename: Diloma Dieudonné
authors.initials: DD
authors.lastname: Soma
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: H.Yamada@iaea.org.
authors.forename: Hanano
authors.initials: H
authors.lastname: Yamada
authors.affiliation: LITE (Liverpool Insect Testing Establishment), Vector Biology Department, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, United Kingdom. Electronic address: rosemarysusanlees@gmail.com.
authors.forename: Rosemary Susan
authors.initials: RS
authors.lastname: Lees
authors.affiliation: Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria. Electronic address: J.Gilles@iaea.org.
authors.forename: Jeremie R L
authors.initials: JRL
authors.lastname: Gilles
mesh_terms: D000818:Animals; D000852:Anopheles / Q000254:growth & development*; D049628:Body Size; D005260:Female; D007303:Insect Vectors / Q000254:growth & development*; D007814:Larva / Q000254:growth & development; D008970:Molecular Weight; D013696:Temperature; D014462:Ultrafiltration / Q000379:methods*; D018508:Water Purification / Q000379:methods*; D060753:Water Quality
keywords: Anopheles arabiensis; Chemical properties; Mass production; Reverse osmosis; Sterile insect technique; Ultrafiltration; Water recycling