Common Effluent Treatment Plants Monitoring and Process Augmentation Options to Conform Non-potable Reuse

The stringency in effluent discharge and reuse standards has made it extremely expensive to discharge the effluents safely or reuse them. Therefore, existing wastewater treatment plants should be evaluated and improved or augmented. With this aim, five existing common effluent treatment plants (CETPs) in North India were evaluated, including: the State infrastructure Development Corporation Uttrakhand Limited (SIDCUL) Haridwar, which processes 4.5 Million Liters per day (MLD); the Industrial Model Township (IMT) Manesar Gurgaon, 55 MLD (comprising two streams of 25 and 30 MLD each); the Lawrence Road Industrial Area (LRIA), Delhi, 12MLD (12MLD LRIA); Mayapuri Industrial Area (MIA), Delhi, 12MLD; and the Integrated Industrial Estate (IIE) SIDCUL Pantnagar, 4.0 MLD. These plants were designed to produce treated effluent for non-potable reuse. Results showed that the integrated efficiency (IEa) of all CETPs was 10–20% larger than standard integrated efficiency (IEs), indicating the suitability of the technology, except for 12MLD at MIA CETP where the IEa was 20% lower than IEs, due to the absence of any biological unit in the process. Combined post-treatment of secondary effluent by coagulation, Ultrafiltration (UF), followed by ozonation for CETP SIDCUL Haridwar, was also conducted for its non-potable water reuse. This process was able to reduce Biochemical Oxygen Demand (BOD) by 77%, Chemical Oxygen Demand (COD) by 76%, turbidity by 96%, and Total Suspended Solids (TSS) by 100%. All these parameters confirmed the effluent standards for non-potable reuse. The color was reduced to 4.0 from 42.0 Pt-Co units by the exposure ozone concentration of 8.3 mg/L for up to 4.0 min on the treated water from SIDCUL CETP, which reduced the color by 90% and complied with reuse standards. Hence Combined post treatment by coagulation, UF followed Ozonation of secondary treated effluent could be a better option for the potable reuse of treated water in various domestic and industrial applications.

Evaluating Fecal Indicator and Pathogen Relationships in Sewage Impacted Surface Waters to Blend with Reclaimed Water for Potable Reuse in North Carolina

Surface waters used for drinking water supply often receive upstream wastewater effluent inputs, resulting in de facto wastewater reuse for drinking water and recreation. As populations grow, demands on water supplies increase. As this trend continues, it creates the need to understand the risks associated with such reuse. In North Carolina, potable reuse has been proposed as a combination of at least 80% surface water with up to 20% tertiary-treated, dual-disinfected, reclaimed wastewater, which is then stored for 5 days and further treated using conventional drinking water treatment methods. The state of North Carolina has set standards for both intake surface water and for the reclaimed water produced by wastewater utilities, using indicator microorganisms to measure compliance. The goal of this study was to quantify fecal indicator microorganisms, specifically E. coli, coliphages, and C. perfringens as well as key pathogens, specifically Salmonella spp. bacteria, adenoviruses, noroviruses, and the protozoan parasites Cryptosporidium and Giardia, in two types of water representing potential candidates for potable reuse in North Carolina, (1) run of river surface water and (2) sewage-impacted surface waters, with the purpose of determining if there are predictive relationships between these two microorganism groups that support microbial indicator reliability.

Progress on legal and practical aspects on water reuse with emphasis on drinking water – an overview

The present study highlights the evolution, the progress and the prospects of future practices of water reuse in the world. The objective was to produce a comprehensive timeline on the global evolution and progress of water reuse. This was achieved through the analysis of the state of the art on the subject. The present study is a qualitative research, where three aspects have been considered to highlight the global evolution of water reuse: i) Regulations, Standards, Criteria or Guidelines (RSCG); ii) Indirect Potable Reuse Projects (IPR); and iii) Direct Potable Reuse Projects (DPR). The study focused on both legal and practical aspects of water reuse and considered 3 timelines in the context of RSCG, IPR and DPR: 29 RSCG instruments, institutionalized from 1918 to 2020, where only 4 instruments were solely dedicated to drinking water reuse; 10 IPR projects; 5 DPR projects. To achieve good, effective results, the regulatory framework must support the objectives of a structured water reuse policy in addition to guaranteeing legitimacy and maintaining public confidence. Integrated water and wastewater management, based on technological and scientific advances, has become a relevant aspect for implementation of more adequate measures by decision makers to address future global water challenges.