A review of literature during calendar year 2013 focused on environmental policies and sustainable development, and economic policies. This review is divided into these sections: sustainable development, irrigation, ecosystems and watershed management, climate change and disaster risk management, environmental policies management, economic growth, water supply policies, water consumption, water price regulation, and valuation.

A review of literature in the calendar year 2015 dedicated to environmental policies and sustainable development, and economic policies. This review is divided into these sections: sustainable development, irrigation, ecosystems and water management, climate change and disaster risk management, economic growth, water supply policies, water consumption, water price regulation, and water price valuation.

A review of literature during calendar year 2011 focused on environmental policies and sustainable development, and economic policies. This review is divided into these sections: sustainable development, irrigation, ecosystems and watershed management, climate change and disaster risk management, environmental policies management, economic growth, water supply policies, water consumption, water price regulation, and valuation.

No abstract

The effects of chitosan characteristics (i.e., degree of deacetylation [DD] and molecular weight) and environmental conditions (i.e., ionic strength and pH) on the flocculation of anaerobic sludge were investigated. The results showed that chitosan enhanced the flocculation of sludge, and the flocculation efficiency depended on both the degree of deacetylation and molecular weight. Chitosan with 85%DD was more effective than that with 70%DD, as the former required a lower dose to obtain 90% flocculation at all studied pH values. In addition, low molecular weight chitosan enhanced the flocculation better than high molecular weight chitosan. The increase in ionic strength (up to 0.1 M) of the suspension helped reduce restabilization that occurred when chitosan was overdosed. In general, chitosan has potential to be used as an effective cationic bioflocculant, which is able to function either in acidic or neutral conditions, and very small amounts of chitosan (less than 4 mg/g dried sludge) are required.