**6.1 Sampling and storage of microbial material**

Microbial materials utilized for the present study have been collected from two wastewater treatment plants, notably:


Acerra wastewater undergoes a traditional activated sludge treatment process, following preliminary removal of gross materials and primary settlement. Activated sludge produced is split between 98% recirculated fraction and 2% fed to thickening and stabilization processes. Colonies populating the sludge flocs have been included in **Table 7**. Samples associated sludge parameters are B.O.D.5 = 20 mg/l and active mass concentration = 2600 mg/l. Solofra plant implements a biological/physical– chemical process over a C.O.D of 7000-8000 mg/l. After a preliminary phase of precipitation with limestone, polyelectrolyte and ferric chloride/aluminum sulphate, wastewater is supplied to a biological plant, with a final activated carbon adsorption stage for the removal or coloring and residual organic matter. Activated sludges of Solofra plant are composed predominantly of proteobacteria, Bacteroidetes, firmicutes with a presence of actinobacteria, planctomycetes and chloroflexi [36].


#### **Table 7.** *Microorganisms of activated sludges.*

Inventory of bacterial matters consisted of 1.5 ml 300 Eppendorf, of which 100 of sludge, 100 of untreated water and 100 of physically-chemically treated water. Also, No. 105 50 ml Falcon tubes, of which 35 of sludge, 100 of untreated water and 100 of physically-chemically treated water. Biodegradative inherent capacity of Acerra sludges in a suspended lab scale bioreactor about a specific substrate such as ethyl acetate had preliminarily been tested by the author [37].
