## 5 Nanoparticles with Microorganisms  
Nanoparticles have significant effects on microorganisms. NPs strain latent detrimental effects on wastewater microorganisms, according to an overview of their antimicrobial properties. Although, at present, statistical data on the NPs' effect on wastewater microorganisms during aerobic digestion are rather minimal, but it still has a remarkable effect [88; 89]. Hence, it is tough to make a particular claim regarding the harmful effect of NPs on wastewater microorganisms. However, minimized efficiency of  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Substrate** & **Iron Type** & **Dosage (g/L)** & **Temperature (\({}^{\circ}\)C)** & \begin{tabular}{c} **Increment in** \\ **CH\({}_{4}\) Yield (\%)** \\ \end{tabular} & \
\begin{tabular}{c} **Increment in COD/VSS** \\ **Removal (\%)** \\ \end{tabular} & **Reference** \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{Scrap iron} & \multirow{2}{*}{10} & \multirow{2}{*}{35} & 10.1\({}^{\text{a}}\) & \multirow{2}{*}{83.3} & [78] \\ \cline{5-6}  & & & & 21.4\({}^{\text{b}}\) & \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{Scrap iron} & \multirow{2}{*}{4} & \multirow{2}{*}{35} & 43.5 & 33.6\({}^{\text{c}}\) & [79] \\ \cline{2-6}  & & & & 145.5 & 56.2\({}^{\text{d}}\) & [80] \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{nzVI} & \multirow{2}{*}{1} & \multirow{2}{*}{37} & 25.2 & 22.0\({}^{\text{d}}\) & [81] \\ \cline{2-6}  & & & & 40.8 & 48.4\({}^{\text{d}}\) & \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{nzVI} & \multirow{2}{*}{10} & \multirow{2}{*}{35} & 131.6 & NA & [82] \\ \cline{2-6}  & & & & 46.1 & NA & \\ \hline \multirow{2}{*}{Pig manure} & \multirow{2}{*}{nzVI} & \multirow{2}{*}{20} & \multirow{2}{*}{35} & 20 & NA & [83] \\ \cline{2-6}  & & & & 159 & NA & \\ \cline{2-6}  & & & 12 & 35 & 41.7 & 105.9\({}^{\text{c}}\) & \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{Srap iron} & \multirow{2}{*}{2.385} & 35 & 38.3 & NA & [86] \\ \cline{2-6}  & & & 16.6 & 35 & 1304 & NA & \\ \hline \multirow{2}{*}{Excess sludge} & \multirow{2}{*}{Srap iron} & \multirow{2}{*}{33.3} & 35 & 25.3 & NA & [87] \\ \hline \hline \end{tabular}
\begin{tabular}{c} ZVI-Zero-valent iron; nZVI-nano scale zero-valent iron; mZVI-microscale zero-valent iron; NA-not available; \\ OFMSW-Organic fraction of municipal solid waste;\({}^{\text{a}}\) acidogenesis phase;\({}^{\text{b}}\) methanogenesis phase;\({}^{\text{c}}\) VSS;\({}^{\text{d}}\) COD. \\ \end{tabular}
\end{table}
Table 2: Summary of anaerobic digestion enhanced by nanoparticles.  
AS and AD processes, absolute collapse of treatment and environmental pollution from contaminated effluents and utilization of biosolids for changes in soil texture may result due to NPs and microbial community contact [90].  
A broad range of microorganisms are affected by the silver ion. Bacterial growth in a variety of medical treatments, including dental work, catheters, and healing burn wounds, has been controlled in recent days by silver ions [91]. Concentration and contact time influencing the mechanism of release of ions from Ag was exhibited by _Escherichia coli_. The leaking of reducing sugar and protein, enzyme inhibition, cell obstruction, and disperse vesicles, which slowly disintegrate, are the detrimental effects inhibiting cellular respiration and cell growth [92].