Enhanced Biological Nutrient Removal Driven by Sludge Carbon Sources Extracted Using Different Mechanical Disintegration Treatments

To find an efficient way to recover and reuse carbon from biosolids for biological nutrient removal (BNR) process enhancement in wastewater treatment plants (WWTPs), the study investigated three methods for sludge treatment and obtained three types of carbon sources with different specification: mechanical disintegration carbon source (MDCS), alkaline mechanical disintegration carbon source (AMDCS), and liquid of hydrolytic acidification after alkaline mechanical disintegration (AMDHCS). After 12 h of absorption (under anaerobic conditions) of these carbon sources with the Biofilm Bio-Nutrient Removal Carbon source regulated Phosphorus Removal (BBNR-CPR) biomass, the biodegradability of humic acid in the sludge supernatant was improved, and the improvement was enhanced by alkali/hydrolytic acidification pretreatment. Carbon sources prepared by different methods were suitable for different temperature environments. At room temperature (25°C±1°C), MDCS with a short preparation time (8 min) and low specific energy consumption [10,400 KJ/kg total suspended solids (TSS)] could be reused for BNR; however, the most effective carbon source at low temperature (13°C±1°C) was AMDHCS, of which the nitrogen and phosphorus removal efficiencies were 48.6% and 100%, respectively.