Development and adoption of wastewater treatment system for peri-urban agriculture in Multan, Pakistan

Abstract

The present research was conducted to assess the feasibility of biological treatment of a typical wastewater (WW) stream in Multan, Pakistan, using daily trends of WW characteristics and to design a wastewater treatment (WWT) system for that stream. The pH (5.8–6.2), temperature (24–30 °C), biological oxygen demand (BOD5: 128–265 mg/L), ultimate BOD (BODu: 227–438 mg/L), BOD/total Kjeldahl nitrogen (BOD5/TKN:5.9–11.2), BODu/BOD5 (1.6–2.0), carbonaceous BODu/nitrogenous BODu (CBODu/NBODu:1.6–2.8) of the WW was found to support the biological WWT. The inclusion of NBOD also indicated the need for nitrification-denitrification. The linear regression analysis of volatile suspended solids (VSS) with total suspended solids (TSS) indicated the high content of organic solids, which also made the WW suitable for biological treatment. The BOD/COD (chemical oxygen demand) <0.8 indicated the requirement for biomass acclimation. The major process units of the WWT system developed included a primary clarifier, cascade aeration, trickling filter, adsorption filter and chlorination contact tank. During the validation of design procedures, considerable removal of TSS (91%), TDS (46%), BOD5 (88%), COD (87%) was observed over the 15 week operational period of the secondary WWT system. The WWT system developed was appropriate as a sustainable WWT system that consumed less energy and had lower operational costs.

Modeling-based performance evaluation of novel cascade cum trickling filter wastewater treatment system

“…The influent pH was observed between 7.2 ± 1.8 to 8.1 ± 0.2 while the effluent pH ranged from 6.9 ± 1.7 to 7.9 ± 0.3. The obtained pH range indicated the feasibility of good biological treatment, effective nitrification and optimum operation of trickling filter (Kanwar et al 2019;Khan et al 2019a, b).…”

“…As cascade aeration is considered as the simple, zero-energy demanding and having less maintenance cost. So, the power consumption of both CTF and CCTF was estimated as 0.3-0.6 kWh/m 3 that was found considerably less than for anaerobic (0.03-3.572 kWh/m 3 ) and aerobic (2 kWh/ m3) membrane bioreactors (Martin et al 2011;Rasool et al 2017;Kanwar et al 2019). The power consumption of CTF and CCTF is generally related to the pumping and recirculation that can be decreased by constructing the systems on a slope.…”

“…Cascade aeration contains 11 steps, and the height of each step was of 0.75 m. The dimensions of cascade aeration system were determined by guidelines of Metcalf and Eddy (2013). These designated dimensions were provided by Kanwar et al (2019). The associated cascade settler having length, width and depth of 3.1 × 3.1 × 1.5 m, respectively, was constructed to settle down the suspended solids.…”

An energy‐efficient two‐stage passively aerated trickling filter for high‐strength wastewater treatment and reuse

“…DO concentration above 1 mg/L is essential for the nitrification process, whereas with low concentrations, both ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) growth rates are reduced (Ma et al, 2016;Wang et al, 2021). In the present treatment system, the natural ventilation through the aeration During the operating period, the pH of the influent varies between 7.2 and 8.5, which is within the optimum range for proper biological treatment and effective nitrification (Kanwar et al, 2019;Khan et al, 2019). The pH of treated UWW decreased significantly (pH = 6.5-7.4), indicating normal biological nitrification inside the trickling filter.…”

“…Kanwar et al (2022) found that the power consumption of both conventional and cascade cum trickling filters was in the range of 0.3-0.6 kWh/m 3 . m 3 ) membrane bioreactors (Garfí et al, 2017;Kanwar et al, 2019;Martin et al, 2011). The power consumption of the developed trickling filter is only related to the pumping and recirculation of water.…”