Evaluation of the Newlands Mashu Anaerobic Baffled Reactor and Anaerobic Filter

Evaluation of the Newlands Mashu Anaerobic Baffled Reactor and Anaerobic Filter
M.loffe¹, N. Melgoza², F. Pinongcos¹, H. Tegley¹, A. Bigelow¹, B. Pietruschka³, M. Palomo², and N. Mladenov¹

¹San Diego State University, San Diego, California

²California Polytechnic State University, Pomona, California

³Pollution Research Group, University of KwaZulu-Natal, Durban, South Africa

Email: mwloffe@cpp.edu

Anaerobic Baffled Reactors (ABR) has been implemented by the German NGO BORDA as a standard component of Decentralized Wastewater Treatment Plants (DEWATS). BORDA has constructed more than 2 500 DEWATS plants in developing countries to treat low and medium strength domestic wastewater. The implementation of DEWATS plants is a possible option for water borne communal ablution facilities in dense informal settlements. This technology is being investigated by eThekwini Water and Sanitation in a DEWATS plant in Durban, South Africa to determine the treated wastewater quality and the expected operation and maintenance requirements.

Discussed in this paper is an analysis of the flow rate profile, movement of solids, COD determination, nutrients uptake of wetland, and biodegradability using fluorescence spectroscopy. The flow rate of the wastewater was determined by magnetic induction flow-meters readings at 60 min intervals using fluorescein and lithium-ion based tracers. The flow rate data was then used to determine the contact time between the microbial layer and the wastewater.The movement of solids within the wastewater treatment system was analysed using the conventional control volume method to approximate the total suspended solids (TSS), volatile suspended solids (VSS), total solids (TS), volatile solids (VS), and turbidity using mass balance in connection with microbial contact time. Total COD and soluble COD analysis was conducted using a titration method. Samples were taken from the first and last chambers of the ABR, effluent from the anaerobic filter, and horizontal flow planted gravel filter (PGF) by manual grab sampling. Samples (before and after centrifugation) were then digested with potassium dichromate and the excess was determined by titration with ferrous ammonium sulphate to calculate COD. In addition to these methods, spectrofluorometry was used to estimate the biodegradability occurring throughout the DEWATS system. Tryptophan-like (285 nm ex350 nm em) and coloured dissolved organic matter (325 nm ex / 470 nm em) peak intensities were measured within each chamber at 0.5 m, 1.0 m, and 1.5 m depths to assess the variation in concentration. Tryptophan-like peaks were then correlated to biodegradation rates.