Situation and Novel Approach for Sustainable Phosphorus Recovery: A Case Study of Thailand

摘要

Phosphorous (P) is an essential nutrient for plant growth. Natural P reserves are being exhausted at an alarming rate due to the intensive use of P as a fertilizer. Globally, 170 million tons of P fertilizer is used each year, with 0.41 million tons (P 2 O 5 ) of that being used annually in Thailand. The extent of P use is ever rising since food production needs to be increased to feed the ever-increasing the world population. Since P is a finite resource, its sustainable use has become imperative and remains a major challenge these days. Domestic wastewaters are rich in P levels, which are usually not recycled due to the absence of appropriate P recovery techniques. It is estimated that more than 40,000 tons of P could possibly be recovered yearly from domestic wastewater in Thailand. P recovery has been discussed for decades, but actual application of technology is still lacking. Among various reasons, P-recovery technology development has mainly focused on sewers and centralized wastewater treatment systems which are not equally suitable in the context of developing coun- tries, where non-sewer or onsite sanitation systems predominate. Electrochemical methods are being devel- oped to recover P from effluents of onsite and small-scale waste water treatment systems. Furthermore, the current practice of draining domestic greywater directly into ditches or water bodies in Thailand, as well as in other developing countries, needs to be changed since it contains significant amounts of P. We recommend draining greywater through onsite treatment systems fitted with P recovery units before discharging it.