## 3 Decentralized Treatment Systems
### Aquaculture Effluent Treatment

Table 3: _Cont._
A box system containing 6 layers (15 cm thickness, 0.45 m\({}^{2}\)) and calcium hypochlorite was tested for 3 months, obtaining average reduction in turbidity 60%, color 59% and microorganisms 100% from collected rain. Blanket saturation occurred after 6500 L. According to Brazil legislation, water does not comply for reuse because color and pH values. A 16 m\({}^{2}\) prototype, the collected water showed reduced suspended solid and heavy metal content (no treatment needed) with respect to rain from roofs. pH and conductivity were also OK, but too high COD value, no reuse. After COD reduction, suitable for domestic non-drinking uses. _Taliparti tililacemun_ and _Sterculia macrophylla_ trees improve stormwater runoff quality, removing TSS, TP, Zn, Cu, Cd and Pb >90% in tropical environment. Floating wetland bioaugmented by addition of bacteria carrying the alkane hydroxylase gene were employed to treat crude oil pollution. After 36 days, 300 mg L\({}^{-1}\) crude oil were reduced to 16 mg L\({}^{-1}\) with bacteria and 56 mg L\({}^{-1}\) without. Treated water lost 85-95% crude oil content and toxicity on fish. After settling, CW planted with _T. angustifolia_ with enhanced aeration, HLR of 1000 L m\({}^{-2}\)/d and 4-6 h HRT, turbidity removal 95.3%, BODs 83%, NH4-N 99.3%, TN 70.8%, TP 66.7%, W.Q. : Egypt national discharge limits. Natural water treated in compound parabolic collectors (80 L) by 2.5 mg L\({}^{-1}\) free chlorine, which degraded in 10 min \(\approx\)80% of microcontaminants and reduced bacterial count to 1 CFU/100 mL in 1 min, without \(\text{ClO}_{3}\)\({}^{-}\) generation and bacteria regrowth after 6 days, residual chlorine 0.5 mg L\({}^{-1}\). At a pilot- and full-scale treatment of lake water to produce drinking water by Filtrasorb 400 and Norit 1240, W was tested for 1 year for the removal of micropollutants and organic matter with and without ozonation. Ozonated water lost > 70% of its organic MP content. Organochlorine pesticide-contaminated groundwater was remediated in situ by creating a permeable reactive barrier (two cartridge 140 L total) and monitored for 112 days. Hexachlorocyclohexanes were reduced by 82% and chlorobenzenes by 60% Efficiency was reduced over time because of saturation and iron inactivation. At full scale, drinking water TP PFAS removal by GAC was evaluated according to filter age and flow rate. Removal efficiency: 67-100%. Old GAC life can be prolonged of -% reducing flow rate (from 39 to 18 L) with water treatment goal of 50 \(\mu\)g L\({}^{-1}\). Cost: 0.058 EUR/m\({}^{-3}\) for WTG 25 \(\mu\)g L\({}^{-1}\)  
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**Process and Methods** & **Notes** & **Ref. ** \\ \hline \multirow{6}{*}{MBR + UV} & A mobile sewer mining unit employed in urban environment produced & \\  & 25 m\({}^{3}\) d\({}^{-1}\) of treated water eliminating organic carbon, pathogens and TSS & \\  & from WW. W.Q. : suitable for urban reuse, irrigation and aquifer recharge & \\  & according to Greek legislation. & \\ \cline{3-3}  & Real-scale plant for WW, 1-year test. EC tank of 7.5 m\({}^{3}\), system treated & \\ EC + band filter + sand filter & 2400 m\({}^{3}\) d\({}^{-1}\), HRT 5-6 min. Because of low removal of TN and TP, water can & \\  & be reused only in non-sensitive environment. Cost: 0.24-0.28 EUR/m\({}^{-3}\). & \\  & TADOX\({}^{\text{\textregistered}}\) system in situ treated water in open drains, 5 h HRT, obtaining: & \\ UV/TiO\({}_{2}\) AOP & COD-63\%, BOD-99\%, TP-96\%, TN-61\%, _E coli_-3 Log, total coliforms-4 Log and reduction of micropollutants \(\sim\)93\%. W.Q. : similar to Class A for pathogens & \\  & content (Indian legislation).