Page 229 - Materials Chemistry, Second Edition

210 Life Cycle Assessment of Wastewater Treatment

Eutropic water / Phosphorus
containing waste water
Reused for removal of phosphorus from waste water Regeneration using water/acids/bases Eluting agent adsorbent Filtration Treated water
Appropriate green and eco Adsorption process
friendly material
Filtration
Phosphorus loaded

Recovered adsorbent Desorption Fertilizer industries
Phosphate solution
Precipitation / crystallization Detergent manufacturing
Phosphorus Banking powder, food additives,
match sticks and tooth pastes
Cement industries, anti
corrosion applicant

FIGURE 10.1 Schematic diagram of simultaneous removal and recovery of phosphorus
from waste water via adsorption process

while removing heavy metals. The phosphorus can be used on agricultural fields.
A significant increase in the bioavailability of phosphorus was noticed with the
introduction of new mineral phases such as chlorapatite, farringtonite, and stanfield-
ite during the treatment process (Adam et al., 2009). Liao et al. (2005) developed
a novel microwave treatment for sewage sludge to recover phosphorus discharged
from municipal wastes. About 76% of total phosphorus was recovered from the
sludge and could be reused on agricultural fields. The rapid disappearance of phos-
phorus from the environment motivated scientists to search for the recovery and
recycling of phosphorus compounds from waste materials. Blocher and his research
team proposed a novel concept of low-pressure wet oxidation for the decontami-
nation of sewage sludge followed by phosphorus dissolution. Additionally, heavy
metals from the sludge were removed using a nanofiltration method (Blocher et al.,
2012). In a different study, phosphorus was recovered from sludge ash through stru-
vite precipitation. Ninety-five percent of phosphorus was extracted, accompanied
by leaching of heavy metals, which was overcome by employing a cation exchange
resin (Xu et al., 2012).
In the past half century, humans have massively intervened in the global phosphorus
cycle, resulting in the mobilization of about half a billion tonnes of limited phospho-
rus into the hydrosphere. Moreover, enhanced pollution due to excessive phosphorus
content has been the motivating factor for the sustainable use of phosphorus, including
recovery and recycling approaches. This challenge has been tackled by the adoption of
green and eco-friendly materials for phosphorus-contaminated waste. Cordell in his
extensive work demonstrated 30 different kinds of methods for the recovery of phos-
phorus (Cordell et al., 2011). The drawback of the old strategies for phosphorus recovery
was their inability to manage the complex waste materials and residues produced during
the treatment method, while some had inappropriate designs along with a high cost.